US President Donald J, Trump has declared that the illicit synthetic opioid Fentanyl has been declared a weapon of mass destruction, WMD. Fentanyl precursors have been added to the Convention against Illicit Traffic in Narcotic Drugs and Psychotropic Substances of 1988. This WMD status is from casting about for justifications to be at war with Venezuela or other countries.
When you are in control of the world’s most powerful military, there must be tremendous temptation to use it to clobber someone. When you’re a hammer, everything looks like a nail.
Intermediates added to the Convention against Illicit Traffic in Narcotic Drugs and Psychotropic Substances of 1988:
“In 2017, two main precursors namely N-Phenethyl-4-piperidone (NPP) and 4-anilino-N-phenethylpiperidine (ANPP) were placed under international control. Since that time, traffickers have adapted their approach to use alternative precursor chemicals for fentanyl manufacture. Three of these precursor chemicals, norfentanyl, 4-AP and 1-boc-4-AP, have now been placed under international control.
The WMD designation is clearly about legally mobilizing the military to interdict transport of fentanyl into the USA. The choice of fentanyl as a drug to manufacture by the cartels comes down to the extremely high potency and the relative ease of manufacture. The high potency, 2 milligrams for a lethal dose, means that it can be highly diluted with another drug and add to the overall potency. The high potency also means that a great many doses can be transported in small containers that may be easier to disguise and transport.
The obvious downside to fentanyl distribution is for the user. How careful are the people who spike intermediate quantities of substances, e.g., heroin or coke, so as not to provide a toxic product when repackaged for individual doses? Fentanyl should be redesignated as a highly potent toxic substance outside of the health care industry. As a drug distributor you probably don’t want your customers falling over dead from your product. That’s bad for repeat business. Regardless, user safety is unlikely to be a major concern to the distribution chain.
Sodium borohydride (NaBH4) can be used in the synthesis of fentanyl, so it is on the DEA Special Surveillance List. Sodium borohydride is a very useful and relatively safe hydride reducing agent that I and hundreds of thousands of others have used over the years in chemical synthesis. Sorry to see possible restrictions on its use.
The problem with this “designation of fentanyl and precursors” is that making a designer drug not cited in some list based the structure of fentanyl is that potent analogs can be dreamt up and produced if the right raw materials are available. Any organic or medicinal chemist should be able to come up with a list of candidates. Using existing drugs as a rough guide, producing obscure analogs is a skill set used by pharma companies frequently: Methyl, ethyl, butyl, futile … as the saying goes.
Wouldn’t it be nice to make some headway on the demand side too?
Fentanyl anecdote-
A few months ago I had surgery that involved my being anesthetized with fentanyl. I’ve been dosed with fentanyl several times and can report that it works well. What I didn’t note until the last instance was that it caused my face to itch badly for about 1 hour after surgery. Turns out this is a normal side effect and is not harmful. I had to wonder if addicts whose heroin was spiked with fentanyl had to suffer from both opioid-caused constipation and an itchy face. They have my sympathies there.
On CNBC today there was a report describing a looming shortage of trinitrotoluene, TNT, in the USA. According to this report, the USA quit manufacturing TNT in favor of importing it around 1986. Weapons-related consumption of TNT occurs both in military explosives for US stockpiles and for exported munitions. With Putin’s ridiculous war against Ukraine, America’s export of TNT-related munitions has increased, depleting the national inventory.
According to CNBC, the USA has been importing TNT from countries like Poland, Turkey, South Korea, Australia, and India. Recently, the price of TNT has increased to $20 per pound, increasing the cost of blowing rock, tanks and people to smithereens.
Some business considerations
If the competitive price for TNT is $20 per pound, then you want to ship it at a cost of at least $10 per pound. Even better would be $5-$8 per pound. This would be wonderful, but the fact is that the commodity chemical business is a high volume, low margin business. A margin squeeze is to be expected. Margins of a few dollars per pound wouldn’t be unusual for commodity chemicals.
Product below specifications can either be reworked or sold as a lower grade of product if there is demand. Commonly, below spec product can be blended with above spec product to pass QA. A TNT production plant coming online will increase the amount of product in the market, leading to depressed prices. What I’ve just said applies to the chemical industry at large, not just for explosives like TNT.
Unlike products such as bulldozers and trucks that leave the plant and go to work to create wealth, military armaments are not tools for wealth creation when used. They are consumables made for offensive or defensive destruction. Mining explosives are used to create wealth, but artillery shells are spent in conflict.
In the meantime, in Kentucky
In response to the precarious dependence on foreign vendors, the US government has awarded a contract to Repkon USA to construct a TNT manufacturing facility in Graham, KY. None other than the elderly Kentucky Senator Mitch “Grandpa” McConnell was present for the ceremony in Kentucky.
A bit of nitroaromatic history
TNT was first synthesized in 1863 by German chemist Julius Wilbrand during research in the area of synthetic yellow dyes. It wasn’t until 1891 that the explosive properties of TNT were discovered by German chemist Carl Häussermann. The earliest reported use of TNT as a military explosive was in 1902 and was used to fill artillery shells. As luck would have it, TNT is relatively insensitive and can be safely melted and poured into artillery shells or other munitions. According to Wikipedia, unlike the British explosive Lyddite, aka picric acid, TNT-filled artillery shells would not explode in contact with ships. Rather, TNT could withstand penetration of armor and then detonate internally. Artillery shells filled with the more sensitive picric acid would explode on contact with armor and explode externally, wasting its energy.
The older cousin of TNT, Picric acid, was used in the Battle of Omdurman, the Second Boer War, the Russo-Japanese War, and World War I. Picric acid was first synthesized from indigo by Peter Woulfe in 1771. It was synthesized purposely in 1841 by French chemist Jean-Baptiste Dumas. Of interest is the fact that the synthesis of indigo and other dyes was a target of much experimentation in Germany in the 1800’s.
Nitroglycerin
A quote from Wikipedia “The nitration of glycerin in 1846 by Ascanio Sobrero. He initially called it ‘pyroglycerine‘, and warned vigorously against its use. In fact, he was so frightened by what he created that he kept it a secret for over a year” (Wikipedia). Nitroglycerin is a nitrate ester wherein the three carbon atoms of glycerin are connected to the nitrogen through an oxygen atom. while TNT is a nitro compound with the nitrogen is connected to carbon atoms of toluene. The great sensitivity of nitroglycerin lies in the C-O-N connections while TNT and picric acid have C-N connections. Nitroglycerin is classified as a “nitro ester” while TNT and picric acid are “nitro aromatics.” The nitro ester functionality is much more susceptible to rapid disassembly by a stimulus like mechanical shock or heat.
The nitration of aromatic substances like benzene, phenol and toluene led to the introduction of powerful and relatively easy to manufacture explosives. Naturally, substances that are explosive attract great attention and have undergone a high degree of practical use to perfect.
People routinely disregard the ills of society, but when it comes to developing weapons of war, we become freaking Leonardo Di Vinci.
WWI saw the wide use of picric-acid-filled artillery shells that produced a new degree of violent destruction where used. At the same time the gas automatic machine gun, invented by Hiram Maxim, was introduced into warfare. WWI set the standard for violent death with the introduction of the Maxim machine gun and high explosives.
Interestingly, there is a medical use for nitroglycerin. It is used to treat angina. I have some at home myself, though I’ve never had to use it, thankfully.
Some words about nitration
Nitration of alcohols and aromatic compounds requires a source of -NO2, usually it’s nitric acid. However, the nitrating ability of nitric acid alone is weak, rather it must be activated to produce a more reactive form of nitrate. Sulfuric acid is a stronger acid than nitric acid and consequently is able to remove an oxygen atom by dehydration of the O-H group of nitrate anion producing water and affording a highly reactive (NO2)+ cation. The 6 electrons sandwiching the carbon skeleton of aromatic rings as with TNT, etc., are susceptible to attack by positively charged species and the (NO2)+ cation does the job. The advantage of nitric acid in all practicality is that a hydrogen atom, H+, is already attached producing a water molecule that will easily detach from the nitrogen to form the reactive species, (NO2)+. [As an aside, in chemical processing, liquids are easier and safer to transfer by pumps and piping as opposed to solid addition.]
Formation of nitro esters and nitro aromatics. Graphics by Buford Pusser.
The production of TNT might seem fairly simple- all that is needed are the cheap commodity chemicals toluene, sulfuric acid and nitric acid plus reactors and other process equipment that can resist strongly corrosive acids. The scale of the process will need to be large enough to capture the economies of scale in accordance with capital costs. Utilities like heating and chilling will be needed as well as possible on-site water treatment if allowed. And don’t forget an idiot-proof written procedure and EHS staff as well as talented management. A properly equipped analytical lab will be required for QA/QC.
More fundamentally you’ll need a remote site on which to build a plant that is supplied with sufficient electrical power as well as water and sewer. The state, county and nearby towns will insist on iron-clad assurances of worker safety and proper hazardous waste management. The state will be watching air emissions closely. Then there is finding an insurer to cover the plant and operations.
If you start a nitration operation, why not plan for products in addition to TNT? It can be unwise to operate a 1 act pony. What if the pony dies?
Today I have a slightly different demographic of readers of this blog than in the past, so I’ve been dredging up old posts into the light of day. This is a renamed post from September 3, 2011. I’ve changed some wording to be a bit more mellifluous if that’s even possible.
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I’ve had this notion (a conceit, really) that as someone from both academia and industry, I should reach out to my colleagues in academia in order to bring some awareness of how chemistry is conducted off-campus. After many, many conversations, an accumulating pile of work in local ACS section activities, and visits to schools, what I’ve found is not what I expected. I expected a bit more academic curiosity about how large-scale chemical manufacturing and commerce works and perhaps what life is like at a chemical plant. I’d guessed that my academic associates might be intrigued by the marvels of the global chemical manufacturing complex and product process development. Many academics would rather not get all grubby with filthy lucre. Not surprisingly, though, they already have enough to stay on top of.
What I’ve found is more along the lines of polite disinterest. I’ve sensed this all along, but I’d been trying to sustain the hope that if only I could use the right words, I might elicit some interest in how manufacturing works- that I could strike some kind of spark. But what I’ve found is just how insular the magisterium of academia really is. The walls of the fortress are very thick. I’m on a reductionist jsg right now so I’ll declare that chemistry curricula is firmly in place on the three pillars of chemistry- theory, synthesis, and analysis. In truth, textbooks often set the structure of courses. A four-year ACS certified chemistry curriculum spares only a tiny bit of room for applied science. I certainly cannot begrudge departments for structuring around that format. Professors who can include much outside the usual range of academic chemistry seem scarce.
It could easily be argued that the other magisteria of industry and government are the same way. Well, except for one niggling detail. Academia supplies educated people to the other great domains comprising society. We seem to be left with the standard academic image of what a chemical scientist should look like going deeply into the next 50 years. Professors are scholars and they produce what they best understand- more scholars in their own image. This is only natural. I’ve done a bit of it myself.
Here is my sweeping claim (imagine waving hands overhead)- on a number’s basis, chemists apparently aren’t that aware of industrial chemical synthesis as they come out of a BA/BS program. That is my conclusion based on interviewing many fresh chemistry graduates. I’ve interviewed BA/BS chemists who have had undergraduate research experience in nanomaterials and atomic force microscopy but could not draw a reaction scheme for the Fisher esterification to form ethyl acetate, much less identify the peaks on 1HNMR. As a former organic assistant prof, I find it sobering and a little unexpected.
A mechanistic understanding of carbon chemistry is one of the keepsakes of a year of sophomore organic chemistry. It is a window into the Ångstrom-scale machinations of nature. The good news is that the forgetful job candidate usually can be coached into remembering the chemistry. After a year of sophomore Orgo, most students are just glad the ordeal is over and they still may not be out of the running for medical school.
I think the apparent lack of interest in industry is because few have even the slightest idea of what is done in a chemical plant and how chemists are woven into operations.
To a large extent, the chemical industry is concerned with making stuff. So perhaps it is only natural that most academic chemists (in my limited sample set) aren’t that keen on anything greater than a superficial view of the manufacturing world. I understand this and acknowledge reality. But it is a shame that institutional inertia is so large in magnitude in this. Chemical industry needs chemists of all sorts who are willing to help rebuild and sustain manufacturing in North America. We need startups with cutting edge technology, but we also need companies who are able to produce the fine chemical items of commerce. Have you tried to find a company willing and able to do bromination in the USA lately? A great deal of small molecule manufacture has moved offshore.
Offshoring of chemical manufacturing was not led by chemists. It was conceived of by spreadsheeting MBAs, C-suite engineers and boards of directors. It has been a cost saving measure that mathematically made sense on spreadsheets and PowerPoint slide decks. The capital costs of expansion of capacity could be borne by others in exchange for supply contracts. There is nothing mathematically wrong with this idea. Afterall, corporate officers have a fiduciary responsibility to their shareholders. Allowing profit opportunities to pass by is not the way to climb the corporate ladder.
We have become dependent on foreign suppliers in key areas who have control over our raw material supply. Part of control is having manufacturing capacity and closer access to basic feedstocks.
The gap between academia and industry is mainly cultural. But it is a big gap that may not be surmountable, and I’m not sure that the parties want to mix. But, I’ll keep trying.
[Note: This post is about replacing the hydrogen atoms along the carbon backbone of a polyolefin polymer with fluorine atoms to produce a fluorocarbon surface on a finished good. Here “finished good” refers to anything from polyolefin pellets, powders, components or blow molded articles such as HDPE bottles.]
Recent news has highlighted the use of fluorinated High-Density Polyethylene (HDPE) packaging for pesticides and other products, bringing more attention to the issue of PFAS/PFOS contamination.
What we’re not talking about is a polymer made from fluorinated monomers or comonomers. This refers to a hydrocarbon HDPE bottle made from ethylene (H2C=CH2) monomer that is fluorinated after the bottle is manufactured.
What’s more, the HDPE fluorination process is said to produce PFAS/PFOS (how?) substances that can migrate. Although this technology is not new, and fluorinated hydrocarbon bottles have been around well before the widespread concern over PFAS/PFOS residues, the significance of such contamination was not fully anticipated. As a chemist, the extensive release of fluorinated low molecular weight alkyl derivatives like PFAS/PFOS came as a surprise to me despite knowing that an analogous situation with fluorinated pharmaceuticals that are getting through wastewater plants due to their resistance to microbiological decomposition. For myself only, very little concern for PFAS/PFOS pollution has been noted. You might suppose that chemists could have led the way to understanding. But, not to my knowledge.
The perfluorinated alkyl materials in question bear a close resemblance to TeflonTM which is known for its chemical inertness and lubricity. In chemistry, Teflon is usually ignored as unreactive with most chemicals, except perhaps molten alkali metals. Strategically placed fluorinated features on a molecule can lend the property of greater hydrophobicity or lipophobicity with increased electron withdrawing properties. The high electronegativity of fluorine pulls electron density towards the fluorine atoms through the sigma bonds of a molecular skeleton. Fluorinated organic acids very often have dramatically increased acidity like triflic acid, CF3SO3H, or increased alkylating reactivity like magic methyl, F-SO2(OCH3). By contrast, fluorinated carbon chains themselves are fairly unreactive and quite hydrophobic, as in water repellant. The water repellency of fluorinated hydrocarbons is a very attractive property commercially.
Below are images of the hydrocarbon hexane in ball and stick form and below in a space filling rendering. To the right is perfluorohexane and below that is its space filling rendering. Hexane is just an example of an “ordinary” hydrocarbon that could be perfluorinated.
Graphics by Sam Hill. Hexane (left) and perfluorohexane (right). As can be seen on the right, the green fluorine atoms are rendered larger than the corresponding white hydrogen atoms because fluorine atoms are larger than hydrogen atoms. In some rendering software, the space filling structures are adjusted to show where some percentage (i.e., 95 %) of the electron density is located. These renderings are by ChemSketch so God only knows how atoms are scaled.
A brief interlude on molecular polarity
Before we go on, there is the matter of polarity, dipolarity, dipolar chemical bonds and dipolar molecules. A dipolar polar chemical bond is one in which the distribution of electrons is lop-sided. That is, one atom of a chemical bond has a bit more negative charge than the other, which is thereby deficient in negative charge, or by default carrying a partial positive charge. Chemical bonds, functional groups and entire molecules can be dipolar.
But charge comes in whole numbers, so how can we talk about partial charge? A covalent chemical bond consisting of 2 atoms, same or different, will hold together because the two atoms share a pair of outer electrons. If one of the two atoms in the bond has a greater affinity for negative charge, then the cloud of 2 bonding electrons will spend a bit more time near the more electronegative atom. This shift leaves the other nucleus slightly deficient of negative charge averaged over time meaning that the positive charge of the nucleus is slightly more exposed to the world.
Graphics by Jed Klampett. Polar and nonpolar molecules.
In chemistry there is a saying- “likes dissolve likes”. This means that a polar solvent like water can more readily dissolve polar solids and may mix freely with other polar liquids. Nonpolar liquids like hydrocarbons can dissolve nonpolar solids and may mix freely with other nonpolar liquids. Amphiphilic substances have both polar and non-polar features allowing them to compatibilize polar and nonpolar molecules together. Soaps and detergents are in this category.
We should be careful here. The polar-polar and nonpolar-nonpolar solubility generalizations above are really just bookends across a vast open shelf of partial solubilities between them. Nonetheless, it is a useful rule of thumb.
So, if likes dissolve likes, and the fluorine atoms on a molecule accumulate a bit of negative charge, then why doesn’t a fully fluorinated organic molecule freely dissolve in water owing to fluorine’s negative polarity via hydrogen bonding with water’s positively polarized hydrogen atoms?
Carbon atoms can form bonds with itself or other atoms in several ways that give rise to different overall shapes.
Back to our regularly scheduled content
In situ fluorinated packaging, a niche within the packaging industry, was not something I was fully cognizant of until recently. I have come to understand that HDPE, along with numerous other polymers, can undergo treatment with elemental fluorine or fluorinated reagents to alter the hydrocarbon polymer’s C-H groups and convert them into C-F groups. This alteration gives the HDPE surface properties similar to a perfluorocarbon like Teflon™. For HDPE pesticide packaging, this fluorocarbon layer reduces the product’s permeability to the pesticide’s components. Package fluorination is all about reducing permeability of the container.
Definition: Hydrocarbon. A category of substances composed only of hydrogen (H) and carbon (C). There are 4 main sub-categories: Alkanes, alkenes, alkynes, and aromatics. A hydrocarbon can be composed of any combination of the 4. The principal mineral sources of hydrocarbons are coal, petroleum and natural gas. A hydrocarbon may also be called an organic substance, where organic refers to a carbon-based substance.
HDPE, high density polyethylene, is a hydrocarbon polymer of ethylene gas and often with various hydrocarbon comonomers. Hydrocarbon polymers, also called polyolefins, are notable for their considerably inert chemical properties. Inertness is the resistance to chemical change. However, contact with certain fluorinating agents like F2, ClF3, NF3, etc., diluted in an inert gas can, at relatively low temperatures, exchange the H atoms of HDPE with F atoms. Eventually, all or most of the H atoms on the polymer surface will be exchanged. A carbon molecule that has F atoms replacing all H atoms is said to be perfluorinated.
Pesticides are meant to be spread over selected parts of the environment to do their trick. A great many pesticides are synthetic organic chemicals so naturally there is the possibility of any given pesticide or solvent to diffuse through a hydrocarbon-based container. Migration of product molecules into the polyolefin packaging, in this case (HDPE), can result in the release of the hazardous contents and compromise the overall containment, possibly resulting in exposure to the public and the environment.
It should be possible to slow the rate of diffusion of any given hazardous material through a non-fluorinated container by simply making the container walls thicker. The polyolefin manufacturers would be in favor of this, but the converters who buy the plastic pellets to blow mold the containers may balk. Their raw material costs would rise and they would have to pass the costs to customers, who will resist the cost increase. Then with the increase in mass flow of polymer melt necessary, perhaps the throughput or required extruder torque might change unfavorably. Hard to say.
Some of the small-molecule bad actors
On March 5, 2021, EPA published the list below of PFAS/PFOS compounds found in the 20-50 ppb level in fluorinated HDPE containers used to store and transport a mosquito control pesticide product.
Abbreviated
Full Name
PFBA
Perfluoro-butanoic acid
PFPeA
Perfluoro-pentanoic acid
PFHxA
Perfluoro-hexanoic acid
PFHpA
Perfluoro-heptanoic acid
PFOA
Perfluoro-octanoic acid
PFNA
Perfluoro-nananoic acid
PFDA
Perfluoro-decanoic acid
PFUdA
Perfluoro-undecanoic acid
These are all perfluoroalkyl carboxylic acids listed by increasing chain length. Notably the terminal carbon is fully oxidized to the carboxylic acid and is not fluorinated. This acidic end gives a chemically reactive handle for further manipulation of the PFAS/PFOS if desired.
PFOA, perfluorooctanoic acid, has been industrially produced by what is now 3M since the mid-1940s. It has been used to place TeflonTM coatings on frying pans. It was originally prepared by the electrochemical fluorination (ECF) of octanoyl (ock TAN oh ill) chloride, the hydrogen saturated 8-carbon acid chloride. ECF produces the perfluorooctanoyl fluoride which is then hydrolyzed to the acid chloride liberating HF.
Perfluorination of HDPE bottles relies on the most electronegative element, diatomic fluorine gas, F2, or other similarly reactive fluorinating reagents, and does chemistry on a solid polyolefin surface. Fluorine gas is diluted in a suitably noninterfering gas like nitrogen, argon or CO2 and then exposed to the polymer of interest at a prescribed pressure, temperature and exposure time. Fluorine atoms replace hydrogen atoms on the polymer chain. According to one source, the rate of fluorination is diffusion limited. This means that the fluorination reaction is very fast. The presence of molecular oxygen with molecular fluorine had a retarding effect on fluorination proportional to the concentration of oxygen gas. The presence of oxygen led to it being incorporated onto the polymer.
Given the advantage of impermeability provided by fluorinated polyolefin articles, it is clear that there are many excellent applications of in situ fluorinated polyolefins. The replacement of glass and metal with lighter fluorinated HDPE containers may save on transportation costs on a weight basis. Whether or not the economics favor fluorinated polyolefins over glass or metal manufacturing costs kg for kg is unclear.
The range of application categories listed above is quite large. Each entry in the list has many individual components that may be subject to fluorination as well. It is no wonder that PFAS contaminants are spread widely around the world. The US EPA has issued a letter (below) to companies fluorinating HDPE to beware of accidentally producing PFAS/PFOS in their operations. Specifically warning about the connection of PFAS formation caused by the inclusion of oxygen in the fluorination process. The letter specifically cites “EPA’s 2020 long-chain perfluoroalkyl carboxylate (LCPFAC) Significant New Use Rule (SNUR) (40CFR § 721.10536), that are found to be present in or on fluorinated polyolefins may be subject to TSCA regulations and enforcement.”
“It is during certain types of fluorination (e.g., the presence of oxygen) that the manufacture of PFAS has occurred. Manufacturers (including importers), processors, distributors, users, and those that dispose of fluorinated HDPE containers should be reminded of this potential for manufacturing PFAS and comply with any applicable regulations under TSCA, as described in the next section.“
“EPA is aware of alternative fluorination processes that use fluorine gas in the presence of gaseous inerting (e.g., nitrogen) without the presence of oxygen that could reduce the potential for unintentional manufacture of PFAS. These alternative processes for fluorination of polyethylene are highlighted in the U.S. Food and Drug Administration’s (FDA) August 2021 letter on this issue as it relates to food contact articles.”
“Requirements under TSCA PFAS Significant New Use Rules. Certain PFAS, including long-chain PFAS as defined in EPA’s 2020 long-chain perfluoroalkyl carboxylate (LCPFAC) Significant New Use Rule (SNUR) (40 CFR § 721.10536), that are found to be present in or on fluorinated polyolefins may be subject to TSCA regulations and enforcement. EPA considers the manufacturing of certain PFAS from the fluorination of polyolefins to be a significant new use under TSCA. LCPFAC chemical substances present in polyolefins due to the fluorination process would be considered byproducts of the manufacturing process because they are produced during the manufacture of the fluorinated polyolefins and do not have a separate commercial intent (40 CFR § 720.3(d)). LCPFAC chemical substances that are byproducts of the manufacturing process for fluorinated polyolefins do not meet the requirements of the byproducts exemption at 40 CFR § 721.45(e)5 and are subject to significant new use notice requirements. Significant new use rules require industry to notify EPA at least 90 days before commencing the manufacturer including import or processing of subject chemical substances for a significant new use. The required significant new use notification (SNUN) initiates EPA’s evaluation of the conditions of use associated with the significant new use. Entities may not commence manufacturing (including import) or processing for the significant new use until EPA has conducted a review of the notice, made an appropriate determination on the notice, and taken such actions as are required in association with that determination. Tala R. Henry, Ph.D., Deputy Director Office of Pollution Prevention & Toxics 2022/03/24.”
Fluorination and fluoridation. What’s the difference?
So we do not make people worried about their fluoride toothpaste or their fluoridated drinking water, let’s sort this out. Toothpaste and drinking water have a soluble ionic fluoride salt like sodium fluoride, NaF, or sodium monofluorophosphate, sodium MFP or chemically Na2PO3F. Sodium MFP is water soluble but not stable in water. It hydrolyzes to release fluoride by displacement by water to form dibasic phosphate. The MFP hydrolysis reaction is: PO3F2− + HO– → HPO42− + F−. The fluoride anion, F–, is not nearly the same as fluorine gas, F2. The F– ion bumps into tooth enamel where it binds tightly with calcium in the tooth: Ca5(PO4)3+(aq) + F−(aq) → Ca5(PO4)3F(s). This is the context in which the word “fluoridation” is used. Fluoride ions bond tightly to calcium++ ions in general. Fluoridation is just a specialized variety of fluorination and is mostly confined to the area of water treatment and toothpaste.
Fluorination is a chemical process wherein fluorine atoms are added to chemical compounds. Contact between organic substances and pure elemental fluorine gas is extremely exothermic and sometimes explosive. The dilution of F2 gas with an inert gas like nitrogen, helium or argon has a thermal safety component as well.
Polymer fluorinationout in the world- Patents
One source of manufacturing information about proprietary articles and processes is the US Patent and Trademark Office, USPTO. In order to secure your legal right to a patent, the patent applicant must disclose the exact art that is being claimed. This is because the world must have a fair chance to avoid infringement. Google Patents provides the exact text of individual patents, US and others. It also provides a timeline showing the ownership of the patent and whether or not the patent is active, expired or abandoned. Google patents also provide links to patents cited in the patent and patents that have cited the instant example.
Being a Google product, Google Patents has extensive and flexible search capacity. Rather than attempt to make a list, it is a better use of the reader’s time to go to the site yourselves and explore. Note that a search will find patents from all over the world as well as patent applications. Google patent provides a English translated version of the patent.
In searching for patents claiming compositions and methods around the fluorination of polymers, more than a few patents can be found. One can search for patents using the USPTO website (obviously) or from Google Patents.
Another good place to look for relevant art is from a patent you have already pulled up in Google Patents. Near the bottom of the patent from Google Patents is a section labeled “Patent Citations.” This section list prior art patents disclosed by the assignee and those found by the patent examiner in the course of the examination process. Prior art is disclosed by the assignee in the granted patent as well, but in Google Patents there are hotlinks to patents to aid the convenience factor.
In situ fluorination
There are companies who will fluorinate the surface(s) of High-Density PolyEthylene (HDPE) and PolyPropylene (PP) containers. HDPE and PP are especially of interest owing to their utility in packaging liquids. These two polymer classes have great rigidity and strength and are in wide use. However, they share certain weaknesses such as air permeability and permeability of the contents. Air permeability is highly undesired in food packaging as it allows for reduced shelf life or customer satisfaction with the contents. Food and drugs may be susceptible to air degradation and possible reduction of shelf life.
Note: The expiration date on a product does not necessarily mean that the product will go bad when that date arrives. The day after the expiration date is that date at which the manufacturer/seller will no longer guarantee “freshness” or some other type of quality. For instance, normal pasteurized milk is not sterile. Pasteurized milk should be good up to 1 week past the code date as long as it has not been allowed to warm up or been contaminated. Once the milk has warmed to room temperature, the normal bacteria loading will enter log-phase growth and could spoil within 1 day.
In situ fluorination is process wherein hydrocarbon polymer containers are exposed to diluted fluorine gas at a specified temperature for a specified time. At the surface hydrogen atoms along the length of the polymer are replaced with fluorine atoms. The result is a polymer along the surface which resembles TeflonTM to some extent. Some of the desirable properties of TeflonTM are then taken on by the HDPE or PP surface. This H/F exchange at the surface does not affect the properties of the base polymer.
There is one caveat, however. The fluorination must be performed with the exclusion of oxygen. One source says that the vacuum chamber in which the fluorination will take place must be pumped down to 0.1 Torr of residual air prior to exposure to fluorene gas.
Fluorination patents
Below us from the description in US5274049A Filing date 1991-07-19, Application filed by SHAMBAN WILLIAM S, W S SHAMBAN AND Co.
A method for the direct fluorination of elastomers “in order to reduce the static and dynamic friction characteristics and to increase the wear life and abrasion resistance of the elastomers. The invention also relates to elastomeric articles modified by the fluorination method.”
“What is claimed is:
1. A method of producing fluorinated elastomeric articles, consisting essentially of the following steps:
providing an elastomeric article, said elastomeric article comprising an elastomeric polymer having a backbone chain having a plurality of hydrogen atoms attached thereto;and
exposing said elastomeric article to gaseous fluorine under conditions sufficient to reduce the friction coefficient of said article without promoting degradation of the tensile properties of said article.”
Claim 8 claims a method using a hydrogen fluoride scavenger …
“8. A method for producing a fluorinated elastomeric article having a reduced coefficient of friction, comprising the steps of:
placing a thermoset elastomeric article and a hydrogen fluoride scavenger in a closed reactor vessel, said thermoset elastomeric article comprising an elastomeric base polymer having a backbone chain, said backbone chain including sufficient carbon atoms having replaceable aliphatic carbon-hydrogen bonds so that a fluorinated matrix of said fluorinated elastomeric article reduces said coefficient of friction;”
In the description the patent cites sodium fluoride, NaF, as an HF scavenger wherein NaF + HF => Na[HF2], sodium bifluoride.
Inhance Technologies LLC filed application US20190040219A1, but it was later it was abandoned due to failure to respond to an office action. The application claimed a multistep method for fluorinating elastomeric workpieces with 20 % F2 in nitrogen and “altering certain mechanical properties such as tensile property [and] the elastic modulus, an impact property, a wear property, etc.“
Systems and methods for processing fluoropolymer materials and related workpieces, US11879025, filed 2021-04-23, Current Assignee: Inhance Technologies LLC. Claims method of removing perfluorinated compounds from fluoropolymers. The core of the art involves placing a fluoropolymer work piece in a thoroughly deoxygenated chamber, heated from 25 C to 300 C and exposed to a fluorinating atmosphere such as F2/N2 for specified time period. This treatment is claimed to remove fluorocarbons like PFOA to non-detectable levels. There is no mention of where the PFOA goes afterwards, but it looks promising if accurate. However, the granted patent is off-limits for 20 years unless a license is obtained or some other arrangement is made.
Fluorination is imbedded deeply into the design of a great many articles of commerce. The water repellency of perfluorinated polymers in fabrics is one of the chief applications of fluorinated organic materials. The inherent lubricity of PTFE, its built-in chemical inertness and its hydrophobicity have ingratiated millions of consumers and have met performance expectations world wide.
Perfluorinated foams for fire protection in aircraft hangers and industrial spaces are valuable for their ability to float on the surface of burning liquid fuels, blanketing the surface as a vapor and oxygen barrier. The suppression of flammable volatiles in a fire by a layer of protective foam can inhibit flashover of the fire, reducing the overall damage of a fire. The fire retardancy of perfluorinated substances inhibits their combustion and discourages continued burning when the flame source is removed. Halogens as a group have been used for fire retardancy and with bromine in particular.
The chemical origin of the fire retardancy properties of perfluorinated organic materials lies in the low reactivity of the -CF2– fluorine atoms with oxygen. In the combustion of hydrocarbons, hydrogen atoms are readily removed by oxygen or radical species to form water. The C-F bond is one of the strongest bonds in organic chemistry and is slow to be removed by oxygen.
Drug molecules are frequently fluorinated in particular locations on the drug molecule. A C-F bond resists catabolic degradation and enhances the local hydrophobicity of the drug allowing for greater half-life and enhanced drug potency. The down side is the resistance to catabolic degradation and excretion. Many drug molecules are released intact into sewage treatment facilities where they also resist degradation, possibly due in part to the fluorinated features. The effect is that fish and other organisms are exposed to the drug. As with humans, fish and other creatures of the waterways and soil did not evolve with biochemical mechanisms to deal with fluorinated organics.
In the in situ fluorination process, PFAS/PFOS side products can form, especially when oxygen is present. This can be monitored by quality control but companies will comply with recommended PFAS/PFOS best practices only if there are regulations or the threat of them. Nations regulating PFAS/PFOS contamination will have to compete with nations who do not impose regulations. This is the usual scenario for nations with heavy reliance on imported articles but uneven regulation.
The state of Nevada is quickly becoming the leading source of lithium in the USA and beyond. In the state there will soon be three major types of lithium ore beneficiation- Brine evaporation, hard rock extraction and lithium clay extraction. Nevada already has in excess of 180,000 active mining claims amounting to 49 % of the total BLM national inventory. In addition to this, Nevada has “198 authorized mining plans of operations, and 282 active exploration notices.” Nevada has a long history of fruitful gold and silver mining.
Nevada had earlier won the gold deposit lottery with the Carlin Trend occupying much of the northwestern section of the state. The Carlin Trend has become an archetype in gold mining. These deposits are often described as Carlin-type “invisible gold” ore deposits. Such a deposit is characterized as sediment hosted and disseminated [Editor: disseminated seems like a bummer]. Gold in such deposits are typically invisible and often only detected by lab analysis. According to Wikipedia, most of the gold mines in the Great Basin of the western US are of the Carlin-type.
But, enough about gold and on to lithium
After 6 years of regulatory scrutiny, a new lithium-boron open-pit mining operation in Nevada operated by Australian mining company ioneer has just been approved by the Bureau of Land Management, BLM, for Rhyolite Ridge. The mine is located in the Basin and Range Province near the southwest border of Nevada and California.
The old joke used to be that a mine is a hole in the ground with a liar standing at the top. With the independent economic evaluations available today as part of the disclosure to investors, the likelihood of being duped by fake or salted deposits has dropped considerably. However, the market value of the ore in the future is still subject rapid and unpredictable change.
If you find yourself flying over Nevada on a clear day, you can easily see the basin and range features of the terrain. Nevada occupies only a small part of the total area. The basin and range province extends north to the Columbia Plateau and south into the Central Mexican Plateau.
A very small part of Nevada’s basin and range landscape as viewed from above the Rhyolite Ridge area in Nevada. Image from Google Maps.
The Basin and Range Province of North America. Image from Wikipedia.
Rhyolite Ridge Lithium-Boron Project
The BLM approval opened up $1.19 billion of potential funding of which $700 million is from a US government loan. According to Mining.com, Rhyolite Ridge is the first new lithium mine in 60 years and the first new boron mine in the last century in the US. [Note: I have to assume “new” means new hard rock mineas opposed to brines or evaporites] While the approval by BLM has opened some doors to funds, not everyone is convinced of the major investor’s liquidity.
So, what is rhyolite?
I can’t improve on the definition found in Wikipedia, so I’ll just quote it with the links intact-
If you have ever seen molten glass and noticed its high viscosity, this gives an idea of what high silica content does to lava. The higher viscosity provided by the silica component suppresses the release of gases until nearer the surface where they are released as bubbles with vigor. It is very much like a comparison between boiling pasta water and boiling marinara sauce. The marinara sauce spatters badly due to its viscosity but the pasta water just does a rolling boil.
Source: Mashed.com. Spattering is a universal behavior of hot, gassy fluids. In this case the gas is steam. Magma also contains steam.
The Rhyolite Ridge lithium-boron (LiB) deposit is said by some to be the only known LiB deposit in the US and only one of two known in the world.
“The Rhyolite Ridge mine will run for 22 years. It will produce 22,000 tonnes of lithium carbonate a year. That’s enough to power 370,000 electric vehicles. It will also produce 170,000 tonnes of boric acid, according to the company. The boron contributes 30% to 40% of the mine’s revenue, providing a buffer against lithium market volatility.” –Mining.com
Around the world new economic lithium deposits are being discovered now and then, and a few are being readied for mining. It was announced recently that BLM has approved operations at the Rhyolite Ridge Lithium-Boron Project in southwestern Nevada.
What is interesting about this Rhyolite Ridge project is that it aims to produce both lithium and boron. I’m not an engineer so maybe I’m overly impressed, but the processing plant they propose seems very clever. They will produce their own sulfuric acid from sulfur and extract waste heat for use in generating steam for evaporation of the extracts and electricity. They are completely off the energy grid.
The extracted ore, now called ROM or run-of-mine, is transported to the plant straight from the mine and sized by crushing to 20 mm pieces. The crushed ROM is then taken to a series of sulfuric acid extraction vats and leached for ~ 7 days. The pregnant leach solution containing the lithium, boron and soluble impurities is then taken to evaporators with repeated crystallizations and, using differential solubility, separates the lithium component from the boric acid. In the end they produce lithium carbonate. The video does show a soda ash (sodium carbonate), Na2CO3, silo so I assume that is where the carbonate comes from to produce lithium carbonate, Li2CO3 and to neutralize residual sulfuric acid.
Silver Peak Lithium Brine
Of interest is the nearby Silver Peak lithium brine operation operated by Albemarle just a few miles to the north of Rhyolite Ridge. The Google Maps image below shows the evaporation ponds at the Silver Peak lithium operation. Silver Peak produces both technical grade lithium carbonate and lithium hydroxide.
Image from the Operational Land Imager-2 (OLI-2) on NASAs Landsat 9. A view from space of the Silver Peak lithium brine evaporation ponds in SW Nevada.
McDermitt Caldera: Thacker pass
Another large lithium deposit was discovered in the McDermitt Caldera along the Nevada-Oregon border. Within the caldera is the Thacker Pass Lithium Mine. This lithium deposit was approved for open-pit mining by BLM on January 15, 2021, though it has been plagued by protests and an injunction. As with the rest of the McDermitt Caldera lithium, the Thacker Pass lithium is described as a lithium rich clay deposit. This is unique for lithium mines since brine extraction and hard rock mining of spodumene have been the norm. Thacker Pass’ lithium deposit is the largest known volcano sedimentary deposit in the US at an average grade of 0.22 %.
In 2023 GM invested $650 million in the Canadian Lithium Americas Corp. The Thacker pass operation is through its wholly owned subsidiary Nevada Lithium, LLC, which is responsible for production. Car giant GM’s investment gives them exclusive access through the first phase of production. Lithium Americans has received a conditional approval for a $2.2 billion loan from the US Department of Energy.
The Thacker Pass measured and indicated lithium resources are 13.7 million tons of lithium carbonate equivalent. Lithium Americas calculates that the recoverable lithium is worth $3.9 billion.
Interestingly, the McDermitt Caldera is possibly the oldest of a sequence of calderas produced by the Yellowstone Hotspot. The McDermitt Caldera amounts to a lava dome that collapsed ~16.4 million years ago forming a large caldera within which several smaller calderas have formed and in which later filled with water forming a lake over the tuffaceous ash. Over time the lake produced sediments that were deposited on the floor of the lake. The source rock is rhyolite which is usually the case in the state.
The Yellowstone hotspot stays relatively constant while the crust moves over it, leaving a trail of calderas and a record of volcanic activity on the surface behind. The McDermitt caldera is labeled ’16’. Source: National Park Service.
Briefly, the lithium clay is excavated, gravel and rocks are removed, and the clay is suspended in water to form a slurry. The slurry is leached by adding sulfuric acid that is produced on-site and the lithium in the ore is extracted into the acidic liquor. Finally, the dissolved lithium is recovered as lithium carbonate and lithium hydroxide. Gangue material is deposited back into the excavated sections of the mine.
The McDermitt caldera contains many breccia and fracture zones and associated with these are deposits of other metal ores. Specifically, mercury from cinnabar ore bodies and uranium from autunite (uranyl, U6+) (Ca(UO2)2(PO4)2·10–12H2O) and pitchblende (uranate, UO2, U4+) ore bodies. Mercury reserves in the caldera, according to USGS, are estimated to be 400,000 flasks.
A Mercurial Rambling
Mercury has been packaged (and still is) at 76 pounds to the flask. This measure got its name from the mining and smelting of cinnabar in the mountains of Peru. One site was particularly rich- Huancavelica, Peru. The Spaniards had known prior to their arrival to the New World that liquid mercury could dissolve gold from ore to produce what we now know as a mercury amalgam. With very strong heating the mercury could be driven off as vapor to recover the precious metal.
Spain had its own cinnabar mine in what is now Almadén, Spain, which produced over 250,000 tonnes of mercury. The Spaniards had considerable experience with mining, refining and using mercury prior to discovery of it in the new world. Mercury was quite valuable to the Spaniards but they were faced with transporting it from, say, Huancavelica, Peru, to the Carribean coast where their ships could load the mercury and distribute elsewhere. Anecdotally, it has been estimated that for every ounce of gold produced in the new world, ten ounces of mercury were consumed.
Luckily for the 49er gold rush miners, cinnabar had previously been discovered in California. You can actually visit the old New Almaden mine museum south of the Bay Area. It is worth a trip if you are in the area.
The Spaniards figured that a man could carry what turned out to be as much as 76 lbs of mercury through difficult terrain to the Caribbean coast. Even better for the Spaniards, they knew how much gold could be extracted per pound (or whatever unit) of the mercury they dispensed. This gave them an idea of how much gold to expect and closer control of the mines. By controlling mercury, they controlled who could use it for mining and how much gold they could recover.
Back to lithium
As of this writing, Albemarle is the largest producer of lithium in the US. But the largest known deposit in the US is at Thacker Pass. The Albemarle Silver Peak lithium brine operation is legally defined as placer mining whereas the Thacker Pass operation is lode mining. The word ‘legally’ is used because any claims filed are restricted to placer or lode mining- one does not transfer to the other.
A Word or Two About Rhyolite
Rhyolite is a type of volcanic rock characterized as a ‘fine-grained extrusive igneous rock‘. Its color can vary from pale light grey to pinkish when composed of mainly quartz and feldspar or dark when of a mafic, low silicate composition was present. A quiet eruption of lava gives a solid, denser rhyolite whereas in an explosive eruption can produce the vesicular pumice. The lower density of pumice allows it to float on water. Erupting volcanic islands can produce floating rafts of pumice in the nearby waters. As magma rises in the throat of a volcano, the pressure drops and dissolved gases can form bubbles which, if they fail to disengage from the magma completely, can be ejected into the cooler air and freeze into ‘foamy’ structure. [Note: the word ‘foamy’ is my own and earth science people cannot be blamedfor this.]
A Bit More About McDermitt Caldera
The United States Geological Survey (USGS) published open-file report 76-535 in 1976 titled Geology and Ore Deposits of the McDermitt Caldera, Nevada-Oregon. A 1978 USGS open-file report by Newmont Exploration, Ltd., 78-926, James J. Rytuba and Richard K. Glanzman, Relation of Mercury, Uranium and Lithium Deposits to the McDermitt Caldera Complex, Nevada-Oregon, goes into greater detail on the three minerals.
Summary: This essay addresses the important role the federal government has played in promoting the American march of progress. The old saying that “Necessity is the Mother of Invention” has a large element of truth to it. It is not enough to identify a problem or challenge. For a person, group or organization to solve a technological problem or challenge, the goal must be understood completely, resources acquired, a plan must be constructed and approved by those who control the purse strings, and skilled people must be organized and set to work on the matter at hand.
The federal government can provide the Necessity needed for attention and resources put to play in achieving a goal. For instance, NASA will set a goal and is able to open a project up for bid. The gov’t can provide seed money to the contractor for prototype equipment to present with their bid. Government grants provide the necessity to stimulate invention, hopefully on a competitive basis.
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I have been a lifelong aerospace enthusiast from Project Mercury forward to the present day. What I’m realizing, however, is that I’m increasingly skeptical of the value of further manned space flight by NASA. Whatever the 6 successful manned Apollo landing missions on the moon may have found tramping around the regolith up there, evidently not enough value was found to compel the USA to go back. Obviously, the Apollo program was partially a geopolitical stunt to rival the USSR for prestige and by many measures the USA won. But what did we win? Prestige and a great many valuable technological spin-offs.
In the early 1960’s the US government financed and organized JFK’s challenge of landing a man on the moon and returning him safely to Earth by the end of the decade. Our government allocated considerable national treasure to the moon landing project and put lives on the line. Arguably, of greater importance than a round trip to the moon was the powerful boost to aerospace, computer, and other technologies. The technology-push advances funded by the government would soon become important economic drivers for industry.
In fulfilling Kennedy’s challenge there was both popular excitement about the space program and more than a little skepticism. The USA was increasingly bogged down with the Viet Nam war. Into the early 1970s, the western geopolitical argument about the advances of communism, the Domino Theory, was still cited, but it was gradually weakened by lack of popular support for the war and the loss of American blood and treasure invested in keeping communist influences out of southeast Asia. By the mid 1970’s, the US had pulled out of Viet Nam leaving behind millions of casualties and little to show for the effort. Added to Southeast Asia was the self-destructive meddling with the Cuban communist state. Castro died of old age in his communist bed.
There is an old saying that went “He’d complain if they hung him with a brand-new rope”. The suggestion was that some folks would complain about simply anything. Beyond the geopolitical and apparent military threat of the USSR beating the US into space were the much-ballyhooed technological benefits of the program. One of the oft-cited spin-offs was a Teflon coating for frying pans. It was an example that most citizens would understand and appreciate. Many incorrectly believed that NASA invented Teflon. Actually, Teflon was discovered unexpectedly in 1938 by the DuPont chemist Roy Plunkett.
Libertarians have argued (to my face) that if we wanted non-stick Teflon frying pans, why not just invent it? The introduction of any new and revolutionary product by a corporation carries financial risk and possible loss of reputation. The vaunted contribution of NASA to perfluorocarbon (PTFE) polymers was to push forward projects that required PTFE specifications. Industry did the rest by finely developing technology for PTFE production to meet the demand. Once there was an inkling of demand, industry kicked into gear. It was market-pull by that time.
NASA is very much in the technology-push world whereas many businesses are more safely oriented to market-pull. Technology-push is about invention of leading-edge vehicles, equipment, substances, instrumentation or services. Technology-push requires early adopters willing to wager that the new tech will give them a competitive edge. Government provides a ready-made early adopter.
Market-pull is where a manufacturer produces known or existing products and services. They compete by offering better availability, price and quality than their competitors.
Technology-push is the world of the tech startup. A start-up founder has a product or service that is sure to be a hit if only their products could get manufactured and pushed into the market. Tech investors will examine the startup’s business and financial plans and take a closer look at the technology or service to be offered. Is there a prototype? Is valuable intellectual property protected under patent? How stable is the supply chain or is there one? Will the company be sustained on the tech product only or will consumables be produced as well.
Importantly, is the technology-push startup looking to produce just a single product or is the technology expandible across a spectrum of applications? What if the product performs below acceptable tolerances or simply fails in the field? A startup with everything invested in a single product model is a “One-Act Pony”. Wonderful though the One-Act Pony may be, it can get sick and die in the marketplace. It can grow old and obsolete, giving way to falling sales and the mad scramble to develop a replacement product. I’ve been a part of 2 startups hoping to produce one-act ponies. The ponies died and we hit the streets.
Investors can analyze market-pull business plans by looking at the economics of demand as well as distribution of existing or similar products. Annual sales can be estimated, EBITDAs calculated, and profit margins uncovered. If the profit picture fits the general business model and timeline of the investors, they can release funding rounds to the startup with benchmarks to be met.
Necessity as the mother of invention?
In normal circumstances, industry operated by ambitious people may be motivated to advance their technology skillset to realize entry into new and promising markets. However, that said, an industry that only acts to match technological advances set by competitors is not showing the mettle required to launch a new paradigm in the technology-push manifold. Merely matching the competition does not quite describe a technology-pusher.
A technology-pusher is likely to find that they must walk the manufacturing highwire without a net and perhaps for a long time. Unless you are quite wealthy, launching a startup will likely hold personal financial risk. Commonly, external funding means that some percentage of ownership or shares will be given to the investors. By the time the product or service hits the market, the founders may find themselves as minority stockholders. Their dreams of grand wealth and influence is tempered by reality.
A naïve book-end view of technology pushers. Scientists are by nature more interested in phenomenology and naturally may see a two-dimensional universe of space and time. Scientists may gravitate to precision and accuracy while the engineer is also interested in not just precision and accuracy but also costs. When developing an engineering design, the engineers will constantly consider costs within the boundaries of space and time. Graphics by Arnold Ziffel.
A technology-push company is often started by engineers or scientists with experience in a particular subfield. Scientists commonly receive little or no business education as a degree requirement. Their role is the science guru. Engineers, on the other hand, fully understand the cost imperatives of a project and are able to design to remain within tight cost constraints.
In science, scientists are the main honchos. In business, engineers are the princes of the kingdom. They design projects, lead them, and come in on budget on time. A CEO with an engineering background is not at all unusual. They understand money part.
Ask yourself this- will your descendants in the year 2125 share in the creature comforts coming from the extravagant consumption of resources that we presently enjoy? Shouldn’t the concept of “sustainability” include the needs of 4-5 generations down the line?
The word ‘sustainability’ is used in several contexts and in contemporary use remains a fuzzy concept with few sharp edges. In this post I will refer to the sustainability of raw materials, fully recognizing that it covers numerous aspects of civilization.
There are wants and there are needs. For the lucky among us in 21st century developed nations, our needs are more than satisfied leaving surplus income to satisfy many of our wants. Will our descendants a century from now even have enough resources to meet their needs after our historical wanton and extravagant consumption of resources dating to the beginning of the industrial age? Our technology stemming from the earth’s economically attainable resources has done much to soften the jagged edges of nature’s continual attempts to kill us. After each wave of nature’s threats to life itself, survivors get back up only to face yet more natural disasters, starvation and disease. This is where someone usually offers the phrase “survival of the fittest”, though I would add ” … and the luckiest”.
What will descendants in 100 or 200 years require to fend off the harshness of nature and our fellow man? Pharmaceuticals? Medical science? Fuels for heat and transportation? Will citizens in the 22nd century have enough helium for the operation of magnetic resonance imagers or quantum computers? Will there be enough economic raw materials for batteries? Will there be operable infrastructure for electric power generation and distribution? Lots of questions that are easy to ask but hard to answer because it requires predicting the future.
Come to think about it, does anyone worry this far in advance? The tiny piece of the future called “next year” is as much as most of us can manage.
Humans would do well to remember that a great many of the articles that we rely on are manufactured goods, such as: automobiles, aerospace-anything, pharmaceuticals, oil & gas, metals, glass, synthetic polymers (i.e., polyethylene, polypropylene, PVC, polystyrene etc.), medical technology and electrical devices of all sorts. Each of these categories split off into subcategories all the way back to a farm or a mine. And let’s remember that both mining and farming are both reliant on big, expensive machinery and lots of water.
The point is that nearly everything we have come to rely on sits at the super apex of many foundational apex technologies.
Each of the contributing technologies holding up any given apex technology were new and wondrous at one time. Think of a modern multicore microprocessor chip. Follow the chip’s raw materials back to the mines and oil & gas wells where the raw materials originated. Once you’ve done that, consider all of the people and inputs necessary in each step getting from the mine to the assembly of a working microprocessor. Each device, intermediate component or refined substance is at or near the apex of some other technology pyramid. To keep moving forward, people need to connect each apex technology input in a way to get to their own apex endpoint.
We mustn’t forget all of the machinery and components, energy to power them, transportation and trained personnel needed to manufacture any given widget. Skilled hands must be found to make everything work.
A given technology using manufactured goods is a house of cards kept upright by constant attention, maintenance, quality control and assurance, continuous improvement and hard work by sometimes educated and trained people. Then, there is a stable society with institutions, regulations and a justice system that must support the population. The technology driving our lifestyles does not derive from sole proprietor workshops in a corrugated iron Quonset building along the rail spur east of town. The highly advanced technology that is driving economic growth and the comfortable lives we enjoy comes from investors and factories and international commerce. A great many products we are dependent on like cell phones are affordable only because of the economies of large-scale production.
So, what is the point of this? Sustainability must also include some level of throttle back in consumption without upsetting the apple cart.
A plug for climate change
For a moment, let’s step away from the notion that the atmosphere is so vast that we cannot possibly budge it into a runaway warming trend. The atmosphere covers the entire surface of the planet with all of its nooks and crannies, but its depth is not correspondingly large. In fact, the earth’s atmosphere is rather thin.
At 18,000 feet the atmospheric pressure drops to half that at sea level. The 500 millibar level varies a bit but is generally near this altitude. This means that half of the molecules in the atmosphere are at or below 18,000 feet. This altitude, the 500 millibar line, isn’t so far away from the surface. From the summits if the 58 Fourteeners in Colorado, it is only 4000 ft up. That is less than a mile. The Andes and the Himalayan mountains easily pierce the 500 millibar line.
Our breathable, inhabitable atmosphere is actually quite thin. The Earth’s atmosphere tapers off into the vacuum of space over say 100 km, the Kármán line. Kármán calculated that 100 km is the altitude at which an aircraft could no longer achieve enough lift to remain flying. While this is more of an aerodynamics based altitude than a physical boundary between the atmosphere and space, the bulk of the atmosphere is well below this altitude. With the shallow depth of the atmosphere in mind, perhaps it seems more plausible that humans could adversely affect the atmosphere.
The lowest distinct layer of the atmosphere is the troposphere beginning as the planetary boundary layer. This is where most weather happens. In the lower troposphere, the atmospheric temperature begins to drop by 9.8 °C per kilometer or 5.8 oF per 1000 ft of altitude. This is called the dry adiabatic lapse rate. (With increasing altitude the temperature gradient decreases to about 2 oC per kilometer at ~30,000 ft in the mid-latitudes where the tropopause is found. The tropopause is where the lapse rate reaches a minimum then the temperature remains relatively constant with altitude. This is the stratosphere.)
Over the last 200 years in some parts of the world, advances in medicine, electrical devices, motor vehicles, aerospace, nuclear energy, agriculture and warfare have contributed to what we both enjoy and despise in contemporary civilization. The evolving mastery of energy, chemistry and machines has replaced a great deal of sudden death, suffering and drudgery that was “normal” affording a longer, healthier lives free of many of the harmful and selective pressures of nature. Let’s be clear though, continuous progress relieving people of drudgery can also mean that they may be involuntarily removed from their livelihoods.
It is quintessentially American to sing high praises to capitalism. It is even regarded as an essential element of patriotism by many. On the interwebs capitalism is defined as below-
Capitalism is an economic system based on the private ownership of the means of production and their operation for profit.
As I began this post I was going to cynically suggest that capitalism is like a penis- has no brain. It only knows that it wants more. Well, wanting and acquiring more are brain functions, after all. Many questions stand out, but I’m asking this one today. How fully should essential resources be subject to raw capital markets? It has been said half in jest that capitalism is the worst economic system around, except for all of the others.
I begin with the assumption that it is wise that certain resources should be conserved. Should it necessarily be that a laissez faire approach be the highest and only path available? Must it necessarily be that, for the greater good, access to essential resources be controlled by those with the greatest wealth? And, who says that “the greater good” is everybody’s problem? People are naturally acquisitive- some much more than others. People naturally seek control of what they perceive as valuable. These attributes are part of what makes up greed.
Obvious stuff, right?
The narrow point I’d like to suggest is that laissez faire may not be fundamentally equipped to plan for the conservation and wise allocation of certain resources, at least as it is currently practiced in the US. Businesses can conserve scarce resources if they want by choosing and staying with high prices, thereby reducing demand and consumption. However, conservation is not in the DNA of business leaders in general. The long-held metrics of good business leadership rest on the pillars of growth in market share and margins. Profitable growth is an important indicator of successful management and a key performance indicator for management.
First, a broader adoption of resource conservation ideals is necessary. Previous generations have indeed practiced it, with the U.S. national park system serving as a notable example. However, the scarcity of elements like Helium, Neodymium, Dysprosium, Antimony and Indium, which are vital to industry and modern life, this raises concerns. The reliance of Magnetic Resonance Imaging (MRI) operations on liquid helium for their superconducting magnets poses the question of whether such critical resources should be subject to the whims of unregulated laissez-faire capitalism. While some MRI operators utilize helium recovery systems, not all do, leading to further debate on whether the use of helium for frivolity should continue, given its wasteful nature.
Ever since the European settlement of North America began, settlers have been staking off claims for all sorts of natural resources. Crop farmland, minerals, land for grazing, rights to water, oil and gas, patents, etc. Farmers in America as a rule care about conserving the viability of their topsoil and have in the past acted to stabilize it. But, agribusiness keeps making products available to maximize crop yields, forcing farmers to walk a narrower line with soil conservation. Soil amendments can be precisely formulated with micronutrients, nitrogen and phosphate fertilizers to reconstitute the soil to provide for higher yields. Herbicides and pesticides are designed to control a wide variety of weeds, insect and nematode pests. Equipment manufacturers have pitched in with efficient, though expensive, machinery to help extract the last possible dollars’ worth of yield. Still other improvements are in the form of genetically modified organism (GMO) crops that have desirable traits allowing them to withstand herbicides (e.g., Roundup), drought or a variety of insect, bacterial, or fungal blights. The wrench in the gears here is that the merits of GMO crops have not been universally accepted.
Livestock production is an advanced technology using detailed knowledge of animal biology. It includes animal husbandry, nutrition, medicines, meat production, wool, dairy, gelatin, fats and oils, and pet food production. There has been no small amount of pushback on GMO-based foods in these areas, though. I don’t follow this in detail, so I won’t comment on GMO.
The point of the above paragraphs is to highlight a particular trait of modern humans- we are demons for maximizing profits. It comes to us as naturally as falling down. And maximizing profits usually means that we maximize throughput and sales with ever greater economies of scale. Industry not only scales to meet current demand, but scales to meet projected future demand.
Extracting a mineral resource to its exhaustion has been prevalent in history. The question is, is it inevitable or can or should it be throttled back?But who will do that in the face of market demand?
Essentially everyone will likely have descendants living 100 years from now. Won’t they want the rich spread of comforts and consumer goods that we enjoy today? Today we are producing consumer goods that are not made for efficient economic resource recovery. Batteries of all sorts are complex in their construction and composition. Spent batteries may have residual energy left in them and have chemically hazardous components like lithium metal. New sources of lithium are opening up in various places in the world, but it is still a nonrenewable and scarce resource. This applies to cobalt as well.
Helium is another nonrenewable and scarce resource that in the US comes from a select few enriched natural gas wells. At present we have an ever-increasing volume of liquid helium consumption in superconducting magnets across the country that need to remain topped off. This helium is used in all of the many superconducting magnetic resonance imagers (MRI) and nuclear magnetic resonance (NMR) spectrometers in operation worldwide. Quantum computing will also consume considerable liquid helium as it scales up since temperatures below the helium boiling point of 4.22 Kelvin are required.
As suggested above, today’s MR imagers can be equipped with helium boil off recovery devices that recondense helium venting out of the cryostat and direct it back into a reservoir. One company claims that their cold head condensers are so efficient that users do not even have to top off with helium for 7-10 years. That seems a bit fantastic, but that has been claimed. Helium recovery is a good thing. Hopefully it is affordable for most consumers of MRI liquid helium.
In the history of mining in the US and elsewhere, it has been the practice of mine owners to maximize the “recovery” of run-of-mill product when prices are high. Recovery always proceeds to the exhaustion of the economical ore or the exhaustion of financial backing of the mining company. Uneconomical ore will remain in the ground, possibly for recovery when prices are more favorable. It is much the same for oil and gas. As with everything, investors want to get in and get out quickly with the maximum return and minimum risk. They don’t want their investment dollars to sit in the ground waiting for the distant future in order to satisfy some pointy headed futurist and their concern for future generations.
It is not normally in the nature of for-profit corporate C-suite executives to aim for resource conservation. People answerable to a board of directors have a fiduciary responsibility to maximize wealth generation for the shareholders. The world of industry is the world of growth. The world of “let’s make enough to get by” is not the world of people who rise to the C-suite. Unfortunate perhaps, but true.
What is needed in today’s world is the ability to conserve resources for our descendants. It requires caring for the future along with a good deal of self-control. Conservation means recycling and reduced consumption of goods. But it also means tempering expectations for extreme wealth generation, especially for those who aim for large scale production. While large scale production yields the economies of scale, it nevertheless means large scale consumption as well. In reality, this is contrary to the way most capitalism is currently practiced around the world.
Sustainability
The libertarian ideal of applying market control to everything is alleged to be sustainable because in appealing to everyone’s self-interest, future economic security is in everyone’s interest. If high consumption of scarce resources is not in our long-term self-interest, then will the market find a way to prolong it? As prices rise in response to scarcity, consumption should drop. ECON-101 right? Well, what isn’t mentioned is that it’s today’s self-interest. What about the availability of scarce resources for future generations? Will the market provide for that?
What does “sustainability” really mean? Does it mean that today’s high consumption is sustained, or does it mean resource conservation by reduced consumption?
Is the goal of energy sustainability to maintain the present cost of consumption but through alternative means? Reduced consumption will occur when prices get high enough. As the cost of necessities rises, the cash available for the discretionary articles will dry up. How much of the economy is built on non-essential, discretionary goods and services? The question is, does diminished consumption have to be an economic hard landing or can it be softened a bit?
Where does technological triumphalism take us?
The generation and mastery of electric current has been one of the most consequential triumphs of human ingenuity of all time. It is hard to find manufactured goods that have not been touched by electric power somewhere in the long path from raw materials to finished article. As of the date of this writing, we are already down the timeline by many decades as far as the R&D into alternative electrification. What we are faced with is the need to continue rapid and large scaling-up of renewable electric power generation, transmission and storage for the anticipated growth in renewable electric power consumption for electric vehicles.
Our technological triumphalism has taken us to where we are today. The conveniences of contemporary life are noticed by every succeeding generation who, naturally, want it to continue. This necessitates that the whole production and transportation apparatus for goods and services already in place must continue. We have both efficient and inefficient processes in operation, so there is still room for more triumph. But eventually resources will become thin and scarcity of strategic minerals becomes rate limiting. Economies may or may not shift to bypass all scarcity of particular articles.
Perhaps a transition from technological triumphalism to minimalist triumphalism could take place. The main barrier there is to figure out how to make reduced consumption profitable. Yes, operate by a low volume, high margin business model. That already works for Rolls Royce, but what about cell phones and sofas?
Something else that stymies attempts at reduced consumption is price elasticity. This is where an increase in price fails to result in a drop in demand. Necessary or highly desirable goods and services may not drop in demand if the price increases at least to some level. As with the price of gasoline, people will grumble endlessly about gas prices as they stand there filling their tanks with expensive gasoline or diesel. Conservation of resources has to overcome the phenomenon of price elasticity in order to make a dent without shortages.
A meaningful and greater conservation of resources will require that people be satisfied with lesser quantities of many things. In history, people have faced a greatly diminished supply of many things, but not by choice. Economic depression, war and famine have imposed reduced consumption on whole populations and often for decades. When the restriction is released, people naturally return to consumption as high as they can afford.
The technological triumph reflex of civilization has allowed us to paint ourselves into a resource scarcity corner.
I’d like to believe that humanity could stave off the enviable conflict that would spark from numerous critical resource shortages, but I doubt the people and nations of the world can do it.
After 26 2/3 years on the job, I’m being let go. Actually, my position and director title are being eliminated as of December 24, 2024, and nothing else is there for me. My company is 4 years into the new ownership, a venture capital company, and it’s likely that thoughts of the big payoff are in the air. In preparation for this the CEO, just back from a board meeting, is cutting costs and polishing up the balance sheet for an impending sale. Or so some believe. The mighty and all-knowing overlords of Oz are looking to cash in their chips.
Anecdote
Early after the buyout I had the occasion to speak with one of the board members before their first on-site meeting. This fellow was the retired founder of a chemical company and owned a personal business jet which he flew to the meeting himself. It was an Embraer Phenom 100 which can be flown by a single pilot and under instrument conditions. Both he and his wife were instrument rated and signed off to fly the twin engine jet as a single pilot. As we got to the meeting room, he was greeted by the board chairman whereupon they began to compare notes on their business jets- a Phenom and a Gulfstream. I left since I had no jet of my own to discuss. I was not dejected but merely amused at the different existence these kings of the world occupy.
Back to the story
Having joined the company in 1998 when it was a family operation and coming from a small liberal arts college teaching background, I adapted well to the isolated, almost tribal, company life. Outside influence was scarce. We were inbred and operating on a remote desert island. I got to wear many interesting hats in the organization, and it made for an interesting job despite the lack of structure. Many years later though and with new ownership, the problem became one of wearing too many hats. My job description got overloaded with diverse activities and defied any orthodox job description. My career had become the kitchen junk drawer. I was warned by a friend and boss not to do this. His counsel was to leave and find a more orthodox corporation, but it was just too interesting. In the end he was right. I should have left about 2004.
These days job descriptions are built to exacting standards. None of the cross-disciplinary general chemist stuff that I was used to. I think this is part of what did me in. Early on I had traveled much of the northern hemisphere on sales and sourcing trips. I managed the sales and marketing department for 6 years, did patent analysis and IP due diligence, wrote and submitted a patent application, did some R&D, led accident investigations, conducted R&D on the pyro- and hydrometallurgy of several rare earth minerals, started a process safety department, conducted reaction calorimetry experiments for over 12 years, and finally jumped into TSCA regulatory compliance when we were short staffed. After 3 years I’m still in regulatory compliance.
I have no interest in retirement and halting all chemistry-related activity and doddering into my retirement years because I really dig chemistry. Sitting on the porch whittling a stick and telling stories is not what I want. But a chemist without an organization is hard pressed to continue being involved with actual chemistry. It is true that for everything there is a season. The transition to the next season has begun.
9/11/24. At present numerous oil production platforms in the Gulf of Mexico have been evacuated because of Hurricane Francine. One of them is the “Who Dat” O&G field. The Who Dat field produces O&G with low wax content and no asphaltene flocculation. The origin of the phrase “Who Dat” comes from the Acadiana region of Louisiana. There are numerous claims to the origin of the phrase and there have been legal spats as to the trademark ownership of the phrase. The NFL in particular has thrown its ponderous weight around in the matter. The reader is encouraged dive into ‘controversy’ for themselves.
The low asphaltene-flocculation of the Who Dat field is fortuitous since asphaltenes can accumulate and choke the well bore or downstream piping, interfering with recovery. The graphic below is borrowed from a book chapter by Abdullah Hussein, Essentials of Flow Assurance Solids in Oil and Gas Operation, published by ScienceDirect in 2023. Fouling by asphaltenes can be removed by dissolution in aromatic hydrocarbons or detergents.
As asphaltene-bearing oil rises in the wellbore, it will begin to depressurize and cool causing the asphaltenes to precipitate out of solution and aggregate, resulting in flocculation and fouling of the wellbore, downstream equipment and pipelines.
Graphic: Note that the higher the boiling point (heavies), the lower on the column a fraction is drawn from. In particular the asphalt fraction must remain quite hot to assure that it can flow away. The low boiling point fractions (lights) are vented off and sent elsewhere for processing. The graphic is sourced from here under the Fair Use Doctrine.
The simplified cartoon of a distillation column above shows that used in petroleum refining to isolate hydrocarbon components (fractions) in broad groupings by boiling point. These columns are quite tall and can be spotted easily as you drive by a refinery. Crude oil has suspended solids that are removed by water extraction which is then vaporized in a separate furnace under pressure. This hot, crude vapor is then pumped into the bottom of the distillation tower. For the non-industrial chemists out there who are accustomed to heating a reaction or distillation vessel directly nested in a heating mantle, this offset heat exchange approach is quite common. The fuel for the furnace can be several in-house sources.
Crude oil is a highly complex mixture of hydrocarbons and NSOs (nitrogen, sulfur, oxygen and heavy metals) with a broad range of structures and boiling points. These petroleum hydrocarbons contain a bit of nitrogen, sulfur and oxygen, produced water, natural gas, and inorganics. The hydrocarbons are further divided into linear, branched, aromatic/nonaromatic and cyclic carbon skeletons in which each can be subdivided again into differing molecular formulas and degrees of unsaturation. At this point the reader may need to take a cool refreshing dip into the pool of chemical bonding and the covalent bond in particular because this has a direct bearing on degrees of unsaturation.
A swerve into the weeds of chemical bonding
Here is the long and short of how the different types of chemical bonds affect the formula and structure of a molecule. Carbon atoms make up the skeleton of a molecule and are connected through the sharing of electron pairs. The shared electrons in a bond spend some fraction of their time in orbit between the two carbon nuclei and as such continue to screen out some of the mutual repulsion of the two nuclei. But that is not all. It turns out that this is where quantum mechanics rises from the murky depths of reality. The two bonding electrons are each able to occupy more space than what is available in the individual atoms and so drop in overall energy just a bit. This energy drop is manifested as heat which diffuses into the local environment. The amount of energy lost consists of a discrete quantity of electron orbital energy and occurs in a stepwise manner. This discrete step change is a “quantum jump”. [Note: a ‘quantum jump’ is often portrayed in the popular media as some type of Disneyesque dramatic and abrupt big shift in something or other. In reality it refers to a discrete step change in energy at the sub-nanometer scale.]
Graphics by Fred Ziffel. Each line between the Carbon atoms represents one pair of bonding electrons.
The number of bonds between the carbon atoms has consequences in the 3D shape of the molecule. In the 3 ball and stick representations below, only skeletal single bonds are shown (for reasons known only to ChemSketch).
Graphics by Arnold Ziffel. Bonds number 2 and 3 are omitted in Ethylene and Acetylene to emphasize the shapes. Note the flat planar shape of Ethylene compared to Ethane.
But what do you mean by ‘aromatic’?
The aromatic feature of a molecule is very special. It has a unique type of pi-bonding involving ‘special’ numbers of bonding electrons arranged in a ring and limited by the formula (4n + 2), where n is a counting integer. For n = 0, 1 2, etc., the numbers of electrons involved will be 2, 6 and 10 bonding electrons alternating in a ring. The most frequent ‘special’ number of electrons is 6, as in 3 alternating pairs of 2 electrons. Here, aromatic does not refer to fragrance, although many aromatic compounds like vanillin do have a fragrance. A cyclic group of 3 alternating bonding pairs of electrons will spontaneously ‘delocalize’ and occupy a lower energy level- a much-favored situation. That is, they will circulate around in a continuous ring and occupy a space above and below the ring atoms in a ‘sandwich’ fashion. Okay, we’re drifting a little too far into the weeds.
Graphics by Arnold Ziffel. Organic chemists draw a lot of chemical structures and, frankly, it can become tedious. To make life easier, certain graphical norms have arisen to stem the tedium.
Knowing full well that I am presenting a highly truncated explanation of aromaticity, I have borrowed 3 representations below of the aromatic compound benzene. Given that single C-C bonds are longer than double C=C bonds, one might expect to find that with both C-C and C=C bonds present, 3 bonds would be longer than the other 3. But this isn’t what’s observed. Measurements show that all 6 CC bonds are of the same length, 1.397 Angstroms. And the CC bond angles are all 120 degrees, again different from C-C bond angles. These observations tell us that all 6 CC bonds are equivalent yet different from isolated CC bonds. Note in the upper right structure the 2 blue rings situated above and below the carbon skeleton. These rings represent delocalized electrons that are off-axis to the C-C bonds. They sandwich the carbon skeleton of C-C bonds. The blue rings show the space where the 6 C=C bonding electrons may be found. The bottom structure is a space filling model showing approximately the space occupied by the electron cloud. Think of it as the location of where another molecule will collide with it.
The imaginary large molecule shown below consists of a central region that is flat and two domains that are kinked and bristling with hydrogen atoms. The structure is shown stationary but in reality, it is vibrating vigorously, tumbling in solution, being battered by adjacent molecules and mashing its way through any liquid that may be around it. You know, the usual liquid scenario. The cyclic alkyl groups on the left are locked in space allowing only limited wagging motion, but the alkyl group on the right is free to rotate about all of the C-C bonds allowing the chain to writhe and snake around in its immediate 3D space.
Graphics by Sam Hill. 3D and 2D structures of an imaginary asphaltene. The aromatic section of the molecule is flat while the alkyl parts are kinked and bristly.
Above I referred to “… the sharing of a pair of electrons.” This is only just 1 part in a story of several kinds of chemical bonding. One carbon atom can bond to another carbon atom with 1, 2 or 3 pairs of electrons, producing 1, 2 or 3 chemical bonds. Carbon can also bond by sharing electrons (covalent bonding) with other atoms like nitrogen, oxygen and sulfur to form single or multiple covalent bonds. Atoms like hydrogen, boron, fluorine, chlorine, silicon, phosphorus, bromine and iodine bond well with carbon but with only a single bond. In general, as we move to the left and down on the periodic table the sharing of electron pairs becomes more and more one sided favoring the atom nearest to the upper right of the table. [Note to the purists: we are going to ignore carbanions, carbocations and carbenes in this post.]
Back to our regularly scheduled program
So what does all this bonding jazz have to do with asphaltenes? The type of chemical bond that makes aromatic rings flat, the pi-bond, is very abundant in asphaltenes. An aromatic ring of 6 carbon atoms has 3 alternating pi-bonds. Such compounds are commonly referred to ‘unsaturated’ meaning they have multiple bonds between carbon atoms rather than bonds with hydrogen- they are unsaturated with hydrogen atoms. These molecules consisting of hexagonal arrays, sharing edges like a thin honeycomb and are able to stack on one another- sometimes called pi-stacking.
Graphics by Arnold Ziffel. Agglomeration is when stacks of asphaltene begin to form. Flocculation is when groups of agglomerated asphaltenes mass together.
The asphaltene component of asphaltene (!?!) has been defined as that fraction which is soluble in aromatic solvents like benzene, toluene and xylene, etc., but not in alkane solvents. From this link, “Asphaltenes are referred to [as] the poly-dispersed distribution of the heaviest and most polarizable fraction of the crude oil.” This property derives from the large fraction of aromatic structures in the asphaltene.
Asphaltenes are a complex mixture of hydrocarbons containing variable amounts of nitrogen and sulfur atoms built into the structures. As a category, asphaltenes are substantially aromatic in nature with rather high molecular weights but may have cyclic and acyclic saturated hydrocarbon, or alkyl, fragments attached. These alkyl fragments lend solubility of individual asphaltene components in saturated hydrocarbon solvents (alkanes) and thus offer a means of semi-selective isolation. Maltenes are asphaltene components that are viscous liquids soluble in n-alkane solvents. Maltenes provide the adhesive qualities in asphalt. Asphaltene is divided into 2 fractions: Asphaltene and Maltene.
The words asphalt and bitumen are sometimes used interchangeably, both referring to the same material. Asphalt is the American English version. To help avoid confusion, the terms “liquid asphalt”, “asphalt binder” or “asphalt cement” are used in the U.S. to distinguish it from asphalt concrete. We recall that concrete is comprised of aggregate held together by cement.
Colloquially, various forms of bitumen are sometimes incorrectly referred to as “tar“. Asphalt or bitumen occurs naturally or can be manufactured. The roadbeds we drive on are “asphalt concrete” where stone aggregate is mixed with hot liquid asphalt as a binder that upon cooling forms a hard, durable surface. In common usage “asphalt concrete” is shortened to asphalt while the British call it tarmac.
Thus far, we have been talking about crude oil-based asphalt. Roughly similar materials like tar or coal tars are derived from sources other than petroleum. Generally, the words tar and pitch are used interchangeably but each can be considered specific to separate starting materials. Tar is a dark brown or black viscous liquid and is the result of the destructive distillation of a wide range of organic materials like wood, peat, coal. or petroleum. Pitch derives just from plant material.
In the early 1960’s, Dr. Fritz Rostler and coworkers of the Golden Bear Oil Company, now Tricor Refining LLC, discovered the cause of asphalt deterioration. He found that during the heat treatment used in asphalt processing and/or under prolonged exposure to sunlight in the presence of oxygen, the maltenes are degraded and their adhesive attribute is diminished, allowing the asphalt/aggregate components to crumble.
The Environmental Protection Agency announced on August 6th, 2024 there would be an emergency suspension on all registrations of the preemergent herbicide chlorthal-dimethyl, or dimethyl tetrachloroterephthalate (DCPA or Dacthal). It has been 40 years since the US EPA has issued such an emergency suspension of registrations. This order has immediate effect.
US patent US2923634A was granted to Diamond Shamrock 1960-02-02 with a single claim-
1. THE METHOD OF CONTROLLING UNDESIRABLE PLANT GROWTH WHICH COMPRISES CONTACTING SAID PLANT GROWTH WITH AN ACTIVE AMOUNT OF DIMETHYL 2,3,5,6-TETRAHALOTEREPHTHALATE.
An early patent claiming the use of DCPA, but not the composition.
Graphic and physicochemical data. PubChem. DCPA structure tilted just a bit for clarity. Octanol/water partition coefficient: log KOW = 4.40 @ 25 °C, water solubility = 0.5 mg/l @ 25 °C, Vapor pressure: 2.5 x 10-6 mm Hg at 25 °C
The octanol/water partition coefficient, log KOW, sometimes called Log P, is a measure of how a substance will partition itself between 2 phases, a hydrophilic phase and lipophilic phase. This logarithm is used to give some insight into the type of living tissues a substance will tend to accumulate in on exposure or dosing. A log KOH of 4.40 represents a ratio (antilog) of 25,119 to 1 favoring the octanol. This indicates considerable lipophilicity.
The industrial manufacture of DCPA is neither complicated nor difficult. The terephthaloyl chloride (pronounced: terra THAL oh illchloride, soft TH as in “thing”) raw material is used in the manufacture of Kevlar and is readily made in several ways. Whether or not the DCPA manufacturer makes their own or outsources it is not available information. In either case, the terephthaloyl chloride is chlorinated to exhaustion (fully chlorinated) and then the methyl ester is prepared by contacting the chloride with methanol to form the diester (pronounced: DYE ester).
Why does DCPA have 4 chlorine atoms on it? Hard to say exactly what the thinking was, but from the process chemistry perspective forcing 4 chlorine atoms on the ring rather than just 1, 2, or 3 solves the problem of ending up with a dog’s lunch of mono-, di-, tri- and tetrachlorinated compounds in the product mix. Individually, each may have differing potency, selectivity, biochemical mechanisms, and human or environmental toxicological properties. Subsequent environmental and tox studies would be complicated by the potential of 4 analogs each possibly requiring individual testing at some point. Another thing to consider is that single component solids are much more easily purified by crystallization than a solution of solid components. A solution of mixed components can be quickly precipitated by cooling or concentrating, but pulling out one pure solid among many solid close analogs can be difficult and low yielding. Single component products are almost always better for ease of processing.
Graphics by John Jacob Jungleheimer Schmidt. The “oyl” fragment of the name indicates the presence of the acid chloride group.
DCPA is a selective non-systemic, or contact, herbicide used for pre-emergence control of annual grasses and some annual broad-leaved weeds. Coverage rates of 6-14 kg/hectare are common.
From PubChem: “/IT IS/ PRESENTLY APPROVED FOR USE ON TURF, ORNAMENTALS, STRAWBERRIES, AND AGRONOMIC CROPS INCLUDING COTTON, SOYBEANS, AND FIELD BEANS. /IT IS/ EFFECTIVE AGAINST SMOOTH & HAIRY CRABGRASS, WITCHGRASS, GREEN & YELLOW FOXTAILS, FALL PANICUM & OTHER ANNUAL GRASSES. /IT IS/ ALSO USEFUL AGAINST CERTAIN BROAD-LEAVED WEEDS SUCH AS CARPET WEED…PURSLANE & COMMON CHICKWEED. /IT IS/ TOLERATED BY MANY CROP PLANTS.”
DCPA is a relatively simple small molecule that is made from cheap and abundant early feedstocks like para-Xylene, Chlorine and Methanol. It has good potency and desirable selectivity in its ability to kill crabgrass in the presence of turf grass. The chemical process steps are well understood, each with a long history of successful use. It can be sold in solid form or in liquid form and may be applied by a large variety of methods. It can be applied for pre-emergence or folial use.
According to EPA “DCPA is a chlorinated benzoic acid herbicide which inhibits cell division of root tips in target plants. It controls many annual grasses and broadleaf weeds in a variety of agricultural crops and ornamental varieties (e.g., broccoli, onions, tomatoes, cabbage, cauliflower, dogwood, azalea). Annual agricultural use from 1998 through 2008 averaged approximately 500,000 pounds over 100,000 acres with broccoli and onions accounting for 79 percent of that use (Ratnayake, 2011). Information also suggests that on average 50 percent of broccoli is treated and 15 percent of onions (SLUA).“
As useful of an herbicide as it may be, it has a dark side that spooked the US EPA into issuing an unusual emergency suspension on August 6, 2024. In particular is the potential toxicity to the unborn and the risk to “post-application workers involved in tasks such as transplanting, weeding and harvesting.” Female farmworkers are at high risk since DCPA has been shown to be toxic to the fetus producing lifelong health problems. The reader is invited to read the link for details in the toxicology. The successive degradation of DCPA is shown below. In addition to hydrolysis, it is also subject to photodegradation in sunlight.
Graphics by John Jacob Jingleheimer Schmidt.
Why wasn’t this discovered earlier? I’m not an EPA pesticide guy, but discovering the specific toxicity of herbicides registered many years previously requires some kind of trigger to get an investigation started. Today, other than an overt incidence of toxic effects making the news, that trigger can be the Registration Review Overview conducted by EPA every 15 years for each registered pesticide.
Having interacted with a certain division of the USEPA for the last 3 years, I can say that there are many intelligent and knowledgeable scientists, engineers and other professionals who try to get things done in a very constricted space bounded by layers upon layers of federal laws converted into regulations. They are about as loved as the Internal Revenue Service and, like IRS, are forced to work wildly understaffed and with an IT system that is decades out of date. A doff of the hat to EPA.
Lamentations on Chemistry 