Category Archives: Chemistry

Bleaches and in-process checks of the enlightenment

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In his 1736 publication Smegmatalogia, or the Art of Making Potashes and Soap, and Bleaching of Linens, James Dunbar describes a process for the preparation of potash.  The intended user of the process was the common Scottish farmer. Dunbar was anxious to imbue the common Scot with the ability to “bleach” his own linens.  It is important to realize that the meaning of the word bleach in the early 18th century is different from contemporary use.  The modern use comprises notions of decolorization through oxidation of color bodies to produce a white appearance.  The 18th century concept involves the apparent cleansing and subsequent lightening of a fabric.

The book begins by detailing the preparation of a solution or extract from ashes called Lee.  To obtain this solution, the “Country-Man” would carefully collect Scottish vegetables such as the wood of oak, ash, beech, “thorns”, juniper trees, and “whins”. Suitable herbs included fern, breckens (or brackens), wormwood, thistles, stinking weed, and hemlock. 

Dunbar is careful to instruct that the vegetation should be burned in the shelter of a house but in such a way as to avoid burning down the house. The purpose of burning the vegatation in a shelter is to avoid having rainwater come into contact with the ashes.  My interpretation of this is that runoff carries away soluble potash.

The ashes are placed in a container and covered with water. The ashes are soaked in water until such time that the Lee “carries an egg on its surface”.  What Dunbar is telling us is that the extraction of the ashes needs to go until the worker obtains in the solution a particular specific gravity- this is a specification. There is some minimum specific gravity of the Lee that will float an egg.  And the higher the specific gravity, the more volume of the egg rises from surface of the Lee. The specification herein is required for the next operation.  In order to carry out a successful saponification of tallow, the Lee solution must be sufficiently concentrated. 

Dunbar then describes steps where the Lee is combined with the ashes of ash, beech, or fern followed by boiling the water off to afford “thickens of pottage“.  The residue is shaped into balls which are then calcined in a fire to afford a substance that may be stored in a dry container for the purpose of making soap. 

The discovery of chlorine in 1774 by Scheele and the subsequent of discovery of chlorine bleaching by Berthollet gave us our modern conceptual notion of bleach and bleaching. The develoment of bleaching powder was made by Scottish chemist Charles Tennant who took a patent in 1799.  Tennant’s associate, Charles MacIntosh, is thought to be a contributor to this invention.  Bleaching liquors and powders soon became an important raw material for the bleaching of paper and fabric.

The procedure described by Dunbar is a chemical process.  It tells the user when the extraction is complete, qualitatively at least, by a folksy means of specific gravity determination. This is really very clever- it uses a common object to do the test and the result is readily apparent.  Bleaching in the early 18th century involved the use of soaps and of urine treatment and bleaching fields- a far cry from what we now think of as bleaching.

Oil Well Torpedoes and Grubbin’ Stumps

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We tend to think of some things as being relatively new. I’m thinking of the gas and oil extraction technique of fracturing, or fracking.  In the 1884 third edition of The Modern High Explosives, Nitro-glycerine and Dynamite by Manuel Eissler, p 311, there is a mention of the practice of exploding nitroglycerine charges at the bottom of oil and water wells to renew or increase the flow. The author states that this is a popular technique in Pennsylvania at the time of writing.

On p 318 of the same book, Eissler describes the economics of blasting stumps. In general, the process of removing stumps was called “grubbing”. Enterprising fellows knowledgeable with nitroglycerine took little time in applying the explosive power of this oily liquid to clearing the land of stumps.  

Eissler describes the economics of explosive grubbing as follows:  Three pounds of No. 1 dynamite cost $1.50, labor cost 20 cents per hour, 25 ft of fuse cost 1 cent per foot, and 17 percussion caps cost 1 cent each.  Grubbing 17 oak stumps cost $22.52 with 99 man hours for chopping and piling the pieces.  Grubbing with an axe took 142 man hours and cost $28.40.  No. 1 dynamite was comprised of 75 % nitroglycerin and 25 % absorbent.

Bertholet’s discovery of potassium chlorate (oxygenized muriate of potash) happened in 1785. He observed

“that it appears to include the elements of thunder in its particles; and Nature seems to have concentrated all her powers of detonation, fulmination, and inflammation in this terrible compound”. 

Eissler goes on to say that attempts to prepare gunpowder or blasting powder with potassium chlorate lead only to loss of life and limb for the luckless experimenters with this compound.  Two of Bertholet’s artisans employed to do experiments with this material were killed in 1788.  The hazards associated with both manufacture and use of compositions of potassium chlorate were too great to allow this substance to see much commercial application by the 1880’s.

In praise of polyolefins

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Being a person nestled in the dark and humid recesses of industry, I find myself boggling at certain things out in the bright and sunny world.  Truly, it boggles my mind how little appreciation people have for polyolefin resins. That is to say, polyethylene, polypropylene and all the myriad copolymers and formulations found thereto.  Ok, let’s throw PVC and polystyrene in the mix as well.

Why do I boggle at this? What makes my head spin in puzzlement? I’m so glad someone asked.  Polyolefin films look innocent enough to be ignored. In their uncompounded state they are clear and colorless or they may be white.  Polyolefin films and extruded components are ubiquitous in packaging and thus are not normally an object of desire. They serve the object of desire. They occupy a lesser state interest in nearly all contexts.   They are made inexpensively enough to be torn asunder from the desired object and tossed wantonly to the side for later clean up.

But if the uneducated user of polyolefins only knew the extent to which modern science and engineering had been carefully applied to the lowly stretch wrap or the roll of 1 mil PE film. If they only knew the scientists and engineers who carefully devised the ethylene crackers to produce high purity ethylene, or if they knew the highly educated people who devise the polymerization process, they might have heard an account of the long march to produce water white films with properties matched to the end use.

Puncture resistance, elongation, fish-eyes, haze, modulus, crystallinity, glass transition temperatures, melt points, low volatiles, melt viscosity and strength- all attributes carefully tended to so that the film appears invisible to the consumer. High gloss, low haze films to make the product look even better.  Low volatiles and residues for food contact use.  Polyolefins engineered for specific densities for the global market.

All of the attributes above to attend to with a continuous polymerization loop that spews 50,000 to 80,000 lbs per hour of pellets into silos and rail cars. Pellets that will eventually go to converters who will blow films and extrude widgets all day long.  All so the consumer product can arrive at its destination wrapped unscuffed and free of dust.

Polyolefin materials are incredibly useful and amazing in their own right. We should have more appreciation for these materials and how they serve our needs.

Seeking simplicity in process scale-up

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My graduate school mentor use to say that you could synthesize anything if you had the right precursors. With enough clever reagent artistry, most small molecules can be assembled, though if only enough for an NMR spectrum.  With chromatography and small glassware, it is not unreasonable to do a few reactions on 1 mg of material and recover enough mass to get a proton and carbon NMR.  Yes, I know that with microfluidics and labs on a chip, much lower quantities can be handled. But I refer to getting your hands on enough material to see.

What most of us who came through graduate chemistry have learned is that there are enough acids, bases, protecting groups, oxidants, reducers, latent functionalities, and catalysts out there to choose from so that some combination should get you to an endpoint in your synthesis.  If not, then  NMR, mass spec, IR, and imagination (with ample hand waving) should at least give an idea of why something won’t work.

Reaction chemistry (not including biochemical transformations!!) can be thought to occupy two broad domains- 1) low temperature, ambient pressure transformations with highly reactive species (preferably named after dead chemists), and 2) high pressure, high temperature transformations with lower reactive species. Most chemists fresh out of school know the former better than the latter. And that drives our problem solving strategies: Finding reactive intermediates that will react between -30 C and 150 C with a 5 lb nitrogen sweep in a kettle reactor.

Sometimes, the dumber brute force approach is worth considering.  What can be done under pressure and at elevated temperature?  Or, what can be done at high temperature and short contact time?  That dusty Parr reactor sitting in the corner may be capable of a goodly bit of magic.  Behind a shield. It is good to visit the high temperature, high pressure world now and then. Of course, our engineering friends already know this.

As far as the search for simplicity goes, consider what merits there may be in thermally driven transformations. Every once in a while it may be a viable avenue for something useful. Try thinking of heat as a kind of reagent. Chemical plants are good at producing heat.

 

The Quicksilver Monopoly

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Hydrargyrum, also known as mercury (Hg) or more colloquially as quicksilver, was in the 19th century the object of monopolistic desire by a large banking concern. In 1835 the Rothschilds acquired the rights from the Spanish monarchy to manage the production of quicksilver in the village of Almaden, located approximately halfway between Seville and Madrid.

The Rothschilds, being ever more interested in controlling their bullion trade, understood that the key to the control of the silver market lay in the disposition of quicksilver. The liquid metal was crucial in the extraction and refining of silver. Silver was purified by amalgamation with quicksilver. Control over the distribution and price of quicksilver in America would put the market in their pocket. They were monopolists- it’s what they do.

Quicksilver has been known for more than 2000 years.  Since Roman times it has been known that everything but gold will float on a pool of quicksilver.  Artisans in Idria, an important old-world reserve of cinnabar in what is now Slovenia, observed quicksilver in its native form in1497.  Quicksilver was mined in earnest in Almaden, Spain, since perhaps the 4th century BC or earlier, according to Pliny. 

Alternating conquests transferred control of Almaden from the Romans to the Visigoths to the Moors and to the crown of Spain, among others.  Having been the seat of mercurial desire for two thousand years, the Almaden cinnabar mines have only recently shut down in the name of public health. Spain’s epic quest for silver and gold in the new world was made feasible through it’s own natural abundance of quicksilver.

Quicksilver was discovered in California in 1845. The New Almaden and subsequently the New Idria mines were quickly pressed into production. The smelting of cinnabar (HgS) into fluid quicksilver is simple in concept and relatively uncomplicated in practice.  A stream of hot flue gases are played over a bed of crushed cinnabar. Oxidation of the sulfide to oxide and subsequent thermal decomposition produces mercury vapor which flows to a condenser surface (brick) where it is knocked down into the liquid state and collected.  Simple technology to perform in undeveloped territory.  Quicksilver was sold in 76 pound lots called a flask. This is thought by some to represent what a laborer (or slave) could reasonably carry.

Within a short time the Californian supply of quicksilver robbed the Rothschilds of their monopoly, resulting in strong price pressure on the European suppliers.  For a few decades, the American quicksilver dominated the Pacific rim. Chinese demand for quicksilver or cinnabar for vermilion was strong.  Silver mining in Mexico and the Andean districts to the south was dependent on quicksilver, most of which was controlled by Spain and later Mexico after its independence. Eventually, the Rothschilds regained control of the market, but at a time when cyanidation and chlorination were playing a larger role in gold extraction. The Rothschilds relenquished their hold on Almaden in 1921.

It is interesting to note that quicksilver, so crucial to the isolation and refinement of gold and silver, was discovered a few years before the discovery of placer gold at Sutters Mill. This happy circumstance surely facilitated the prompt extraction of wealth from the gold and silver mining districts that opened up in the west.

Adiabatic Delta T

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We ran our first experiments in the reaction calorimeter today. They were very elementary, involving only the metering one reactant into another at constant reaction temperature.  The results suggested strongly that the reactants were consumed promptly and that good control of temperature is obtained by adjustment of the feed rate. Halt the feed and Qr falls off promptly. This is a very desirable attribute in semi-batch processing. 

From the data workup we determined the adiabatic ΔT, or ΔTad, and were able to follow the heat evolution measured in several ways, but most interestingly in watts per liter. It is desirable to know how many watts of heat evolution your reactor is capable of removing. Engineers think in terms of heat evolution as watts per unit volume. Calibration of a reaction vessel can tell you how many watts of heat the reactor can remove at a defined level of fill and agitator speed.  RC1 data can tell engineering how many watts per liter the reaction mass is capable of. 

Next we ran the reactor in adiabatic mode where the jacket temperature is programmed to follow the reaction mass temperature. The idea is to exert dynamic temperature control via the jacket to make the vessel behave as a Dewar.  We predicted the maximum reaction temperature  by simply adding the ΔTad to the initial temperature. We allowed the reaction enthalpy to ramp the temperature.

The actual endpoint temperature was within two degrees of the predicted temperature and below the bp of THF. This is a measure of the potential for runaway.  If the Maximum Temperature of the Synthetic Reaction (MTSR) is below the solvent bp, then you are in a lesser hazard zone. This temperature would be achieved in an adiabatic system.

A few observations- the heat capacity, Cp, is not constant over the course of a reaction. A little reflection should suggest this.  But it does not automatically follow that the Cp increases in magnitude over the reaction progress, which would offer some thermal buffering capacity.

A Fine Caloric

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I’m getting to know the RTCal software that animates my RC1.  Thinking about reactions in terms of their enthalpy profile continues to provide deeper insights for an organikker like me.  It is yet another indication that P-Chem is the central pillar of the central science.  

Our culture is driven foreward by exothermicity. We energize the machines of progress and of war by harnessing the exothermic drivers, be they nuclear or chemical.  

Our exothermic sun pumps a global weather machine that provides the motive force to spin the wind turbines to energize our iPads. The sun evaporates water for it’s eventual depostion at high gravitational potential for the release of hydroelectrically accelerated electrons.  Hydroelectric power is an expression of stellar nuclear exothermicity.

The thermal web of our world is an eternal equilibrium of latent and sensible heat flows.  Water’s latent heat of condensation helps to ramp up thunderstorm formation with the result of flowers and high fructose corn syrup and tornados.  The metabolic heat of formation of water and CO2 warms our bodies and provides animation for our desires and our many methods of locomotion.   Dancing and laughter and lust thrive because of exothermicity.

Our lives are spent in the semi-fluid atomic matrix of our bodies while a continual stream of energy flows through them, energizing  metabolism through the magic of ATP and then diffusing into the surroundings.  This energy has resulted in the universe becoming self-aware through the sentience of material beings.

Eventually, because of the disorder accumulated by the large number of exothermic transformations inherent to continuous metabolism, our legs will stiffen and our jaws will lock shut in death as the stream of energy ceases to issue from us. The transience of sentience is rooted in thermodynamics.  How this can be is still quite mysterious.

Ways to be a chemical entrepreneur

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I had a discussion with some professor friends recently about the subject of entrepreneurialism among chemists.  I made my usual points about how people become captains of industry. Be more like an engineer. Preferably one with an MBA.  Naturally, my professorly friends were unmoved. Having spent their entire careers in academia, they just didn’t know about this. I didn’t expect them to.

After I made a gross generalization about the lack of entrepreneurialism among chemists, one prof pointed out that in her field of research, there were indeed people who were starting ventures.  I do not doubt this. But it made me think.  People, perhaps especially those in higher education or just advanced technology, naturally conclude that an entrepreneurial venture has to be based on new technology.  Yes, we need people to start businesses in nanotechnology or what ever you call the latest iteration of biochemistry. We need to have a constant churn of people trying to put new products and capabilities on the table.

But we also need businesses who are able to make polysubstituted phenols, anilines, pyridines, alcohols, ketones, aldehydes, halides, and all of the other “ordinary” raw materials and intermediates that are now largely made in Asia. We need companies who will make 100 kg or 1 MT of some obscure organic material.  Entrepreneurialism isn’t just about the bleeding edge. It is about having a dream and seizing opportunity.  It can be cookies or chemicals.

For the most part, intermediates have moved to Asia because of the economics of batch processing fine chemicals. And a moribund approach to chemical manufacturing in the USA. Chemical manufacturing in the USA is complicated. There are environmental permits, TSCA, high waste disposal costs, high labor costs, expensive processing equipment, and layers of business structure to manufacture safely and with high quality. A chemist faced with navigating the maze of regulations, engineering details, and business operations is a busy person indeed.  Few people can do all of it alone.

There are two fundamental approaches to starting a technology company- Market pull and technology push.  Market pull is an activity where one builds manufacturing capacity with the intent of filling it by making exsting items of commerce. Technology push is where one intends to construct a new kind of technology in the form of a service or widget. Market pull is an approach wherein customers buy known technology. Technology push is the activity where the customer is asked to buy into a new product or service. In this case, you’re necessarily asking customers to be first adopters or to find new forms of value.

I’ve seen startups fail because their one-act pony didn’t work. Instead of trying to make a go of it with a one-act pony, a whole circus of acts should be going at once.  A batch reactor is capable of making many things. A plant built around one product is entirely dependent on that one product.  Batch reactors occupied with products from many market segments are batch reactors that will remain busy over a variety of market conditions.

Pharmaceutical intermediate manufacturing is a business weighed down with substantial overhead and structural immobility.  It is not automatically a great place to start. The GMP world is very complex and peppered with many operational land mines. Many early intermediates are not covered under GMP. That is a good place to start. 

ISO certification is another area where I take issue. While ISO certification brings good business practices, it also brings layers of administrative structure. It is possible to mimic this structure without formally adopting it. The ISO label on you advertising will impress some buyers, but a surprising niumber will be indifferent. If you want to be in pharma intermediates, this will be necessary.  What an ISO certification says is that you will do what you say you are going to do. That is a good idea regardless.

What has to change is the economics of manufacturing in the USA. One way to do this is automated synthesis.  A good example of a problem:  How would one automate the synthesis of an OLED chemical like 1 MT of 8-hydroxyquinoline? This is an existing item of commerce, so entry into the market means taking share from someone else. You’ll probably have to best the market price by 10 % at minimum to induce someone to switch vendors. 

The chemistry isn’t cutting edge, but the processing economics may be. This is an example of how entrepreneurialism can and should  tackle manufacturing problems and gain a competitive edge. Since labor cost is a huge driver, find a way to shave off labor. An entrepreneur’s competitive edge may be process cost savings alone. You don’t have to wait for a scientific paradigm shift.

Part of success is just showing up. Just having capacity and a knack for a particular transformation can attract buyers. If you are handy with borylation and are flexible, somebody will call and want a quote. And maybe a sample. Pretty soon you have a PO and a deadline.

It is good to consider that an advance may be in the form of processing economics, not just the science.

Thoughts on Process Development. Outsourcing.

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I have not put pen to paper (Okay. Fingers to keys) on process development lately. I can’t discuss much in the way of specifics. But there are some generalizations that can be put on the table for discussion.

When should you outsource a raw material? Depends. Does the process for the raw material match your skill set? Namely, does it require, say, bromination of an olefin or an aromatic ring? This can be deceptively troublesome. It is easy to scribble down a reaction mechanism for a bromination. It can seem like a no-brainer to say “yeah, we can do that”. Same is true for a Sandmeyer or a Friedel-Crafts reaction or some oxidation reaction for instance.

You may not do much of a particular kind of transformation or handle certain reagents enough to have an institutional expertise to safely handle some materials. You may have safety kingpins who will nix some reagents because they don’t like the looks of the MSDS.  Or, your pots and pans may be booked well into the future and you have no opportunity to make the raw material.

The trouble with outsourcing a raw material is that the supplier’s price is your cost which must be passed along to your customer. You may or may not have the margin to play with to do much outsourcing.  If you suddenly need to outsource a raw material, you will have to find a shop that will make the stuff.  Preliminaries include doing a secrecy agreement, a disclosure of the desired material, and possibly disclosing a technology package.  After the disclosures it might transpire that the vendor isn’t interested, they can’t do the job in the desired time frame, or they want too high of a price. Lots of things can go wrong.  Meanwhile, you’re relentlessly screaming down the timeline towards you’re own delivery date. You should be planning your outsourcing 6 to 12 months in advance. Or even 18 months.  Outsourcing always involves the discovery of new failure modes.

Let’s say that they agree to work up a quote. There is the matter of specifications. They’ll need to know some specifications even before they quote a price.  What kind of purity are you needing? Be reasonable now. There is what you want and what you can get by with. OK, you can live with “97 % purity”. What does that mean? Does it include solvent residuals? What about color and haze or mesh size and appearance? If it comes in at 96.8 %, are you sure you want to reject it?  If it can be easily reworked, and you have the time to spare, rejecting the material might be the best choice. But if they are late and you are late, you may have to take the material on waiver.

Apart from the mere chemistry is the matter of TSCA regulations and/or import restrictions. Will your vendor have to file for an LVE (low volume exemption) or is the material already on TSCA?  An LVE will take time even if everything goes well. Need to put these regulatory filings into the timeline.  Want to import bulk Hazardous When Wet materials? Plan on a boat ride across the ocean.

Asking a company to develop a new product for you requires good communication, person to person relationships, and lots of patience.  Your custom vendor may be smaller than you are and may have considerable resources tied up in your order. They’re taking some risks as well. Shoot for win-win.

Retro NMR

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We received our picoSpin 45 MHz NMR last week. It’s the size of a toaster and sits on the benchtop next to the computer. We brought in a bunch of chemists to see a demonstration. Most of them were fresh PhD’s on their first job out of grad school. I think they were non-plussed. What on God’s green earth would someone accustomed to using 300-500 MHz NMR want with a low field FT instrument like this?

Let me say that I am a fan of this thing and the company. Yes, it is retro in some ways. It lacks the sensitivity and features many of us are used to. However, it is an FT instrument and can be used to examine a great many substances. In a high field instrument, it seems like everything  is a doublet of doublets. Not in this instrument. For routine analysis of reaction completion, for instance, you may already know the spectrum of your product or starting materials. One or two reasonably isolated diagnostic peaks is all you need to gauge the state of your reaction. You almost never need coupling constants and fancy 2-D spectra at this point. Often, high resolution amounts to excess capacity. And you can have picoSpin in the lab with you. No need to trudge to the NMR room for a routine spectrum. Oh yes, it’s $20,000 for the unit.

We have a high field instrument, but not at my location. Between the GCMS and the picoSpin, I have a good bit of analytical capability.  What I like about this is that the picoSpin offers a lot of analysis per dollar. Of course a high field instrument offers superior capability. But the fact is that most instrumentation on the market today provides considerable excess capacity. For instance, how much of the capability of Microsoft Excel or Word do you actually use? Perhaps 10 %?  I’d offer that a large fraction of the total dollar amount spent on scientific instrumentation worldwide amounts to excess capacity.  People are easily dazzled by the possibilites in a list of features. Sales people know this and actually depend on it.

So, I’m exploring how this miniature marvel can be integrated into daily use in a chemical manufacturing plant. Chemists are a stubborn lot and it may be that I can’t crack this nut. We’ll see.