Category Archives: Chemistry

The American gold rush and relativistic electrons

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Exactly why do people value gold? Is all of the allure of gold due to its color? What if gold metal did not have the golden color? Instead, what if it had a silver luster like its neighbors on the periodic table of elements? Would we find it quite so appealing?

There are many reasons why people might desire gold.  The motivation to possess gold would surely vary based upon where in the value chain the metal was encountered.  Gold prospectors might value gold because it was an item of trade. Artisans would value gold for more pragmatic reasons relating workability.  Rulers would value gold because it was an asset that could be put in the treasury and later used to buy influence or fund military adventures. Thieves and plunderers valued gold owing its high value per unit volume  and the ability to offer it in trade virtually anywhere.  

Here is what we can say for sure about gold.  It’s high degree of inertness means that it can retain its golden luster indefinitely and bestow an everlasting aspect. Its malleability and ductility means that metalsmithing with fairly primitive tools was feasible. Gold could be hammered into thin sheets that could be cut, punctured, and otherwise worked by artisans to produce impressive art objects. Gold could be worked to produce all manner of ornamentation for the sake of religiosity, as an ostentatious display of wealth and power, or for coinage. Whatever the context, gold leaves an impression on people, aesthetic or otherwise.

Here is where it all gets interesting. You see, one of the consequences of Einstein’s theory of relativity is that as an object approaches the speed of light, c, its mass increases by an amount defined by a fairly simple mathematical relationship. An object’s rest mass is less than its mass appreciably near lightspeed.  The term “relativistic” refers to effects relating to objects traveling near lightspeed.

It turns out that some of the outer electrons around heavy atoms like gold and mercury are moving at an appreciable fraction of the speed of light- they are relativistic electrons.  If these relativistic electrons are at the outer, valence level, then aspects or behaviors affected by relativity may become apparent by how the atom interacts with light or other atoms. 

Chemistry is about the behavior of electrons confined to the space in the immediate vicinity of nuclei, or bound electrons. In particular, the electrons outer, valence, electrons. This is the realm of chemistry.  Chemists go about their business manipulating these electrons for fun and profit. Virtually our entire material experience of life is dictated by the manner in which these electrons interact.

In the case of gold, the 6s electrons are moving at a significant fraction of the speed of light. The magnitude is 58 % of c, according to one internet reference. At this velocity, the electron mass has increased by a factor of 1.22 times its rest mass. This being the case, the Bohr radius of the orbital is contracted by 22 %. 

The implication of this perturbation in orbital size is that an electronic transition between the 5d and 6s orbitals shifts out of the UV range and into the visible band. The molar extinction from the UV cutoff to about 500 nm is high enough that metallic gold takes on its characteristic golden hue from the reflected light.

Gold is not the only element to be affected at the valence level by relativistic effects. Mercury is also affected. The contraction of the 6s orbital results in relative inertness of the 6s^2 lone pair and poor interatomic (metallic) bonding, resulting in the unusually low melting point of mercury.  Indeed it is likely that most of the interatomic attraction is due to van der Waals forces, which is notably weak.

The inertness of the 6s lone pair reveals itself in the oxidation states of bismuth, which has stable oxidation states at +3 and +5. Like other pnictogens, bismuth (III) compounds have a lone pair. But unlike nitrogen and phosphorus lone pairs which are reactive and an important part of their ordinary chemistry, bismuth’s 6s lone pair is rather inert and not significantly hybridized. Triarylbismuth (III) compounds are trigonal planar with the lone pair taking spherical s-orbital symmetry.  UV-Vis experiments will show that for some simple BiAr3 compounds, the n->pi* transition has a very low extinction coefficient, unlike the analogous Ph3P.  Exposure to Pd(II), for instance, will show scant indication of coordination in the UV spectrum, again unlike Ph3P.

This is quantum chemistry stuff that the reader can run down later. What is of interest to me in this post is the fact that, without knowing it, gold prospectors, miners, and mill operators of the 19th century took full advantage of certain relativistic effects in their search for gold.

The first relativistic effect the early miners took advantage of was the simple fact that gold is a colored and relatively inert metal. It could be spotted by simple inspection in streams and quartz veins. The color of gold made it impossible to confuse with other metals. Ofcourse, iron pyrite was always a problem, but there were simple ways to test for pyrite.

The other relativistic tool used by miners was amalgamation of gold (and silver). Mercury, being a metallic liquid by virtue of relativistic valence electrons, could be intimately contacted with gold dust or larger particles to form a solution that would remain liquid up to some modest fraction of gold. Mercury, being quite dense, would naturally seek the low points where the gold would also be found. This dissolution could be affected by simple sloshing or by grinding the mercury with the ore in an arrastra or an amalgamation pan.  After agitation, the mercury would pool and could be easily collected.

Later amalgamation techniques would combine aqueous cyanidation of the ore in the presence of mercury in hopes of better gold and silver  recovery. Reduction of gold or silver chloride occured in-situ to provide amalgam.  Amalgamation of ore that had been chlorinated by roasting in the presence of NaCl was a common solution to the serious problem of sulphuretted auriferous or argentiferous ore.

The miners of the 19th century American gold rush certainly didn’t know that their task of extracting gold would be aided by the effects of high velocity electrons. Most people walking around today don’t know or even care about this more than 55 years after the passing of Albert Einstein.  But it goes to show how subtle effects of nature can affect our lives in unexpected ways. And this is just one of many such nuances of physics.

Process development and struggle

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One of the hazards of having a degree in chemistry is the appealing idea that you can explain everything and predict everything on the basis of textbook notions on solubility, electronegativity, pKa’s, or molecular orbitals. These are important things to be sure. But in the field, the recall of knowledge isn’t always enough. More often than not you have to collect data and generate new knowledge.

Rationale of a result on the basis of hand waving and a few reference points can seem compelling in a meeting or brainstorming with a colleague to understand a problem. But in the end, nothing can top having solid data from well conceived experiments.

My chemical “intuition” have proven wrong enough times now that I am deeply skeptical of it. After prolonged periods of absence from the lab I find myself resorting to a few cherished rules of thumb in trying to predict the outcome or explain the off-normal result of a process.

In chemical process development there is no substitute for running experiments under well controlled conditions and capturing solid results from trustworthy analytical methods. It is hard work. You may have to prepare calibration standards for chromatographic methods rather than the preferred single-transient nmr spectrum  in deuterochloroform.

We’re all tempted to do the convincing quick and dirty single experiment to finesse the endpoint. Certainly time constraints in the manufacturing environnment produce an inexorable tilt towards shortcuts. But in the end, depth of knowledge is only had by hard work and lots of struggle in the lab. The most important part of science seems to be to frame the most insightful questions.The best questions lead to the best experimental results.

Process Intensification and the Chemical Marketplace

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Somewhere along the timeline of a given chemical plant process a manager will (or at least should) ask the question: “can we run this process in a more efficient and safer manner”?  Chemists and engineers may be set to work finding ways to extract more profit from a process.

There are numerous ways any given process may be improved. How that is done specifically depends on the process, obviously. But certain generalities can be made that serve as a guideline in thinking through the process.

In this essay I will limit my comments to batch or semi-batch processing and to specialty and fine chemicals. Continuous processes and commoditized products are out of the scope of this essay.

Batch and Semi-Batch

A batch process is one in which a vessel is charged with raw materials which are allowed to react to form a desired product. A semi-batch process is one in which raw materials are metered into the vessel over the course of the reaction. From a process safety perspective, the big difference between the two is that the batch reaction is the one with all of the reaction energy contained in the vessel from the start. A semi-batch process is one in which the energy is metered in based on the limitations of heat transfer capacity.

Commodity Chemicals

Some chemicals are commodity products and others are specialty or fine products. A commodity chemical is a product which is produced at a large (relative) scale, commonly in a continuous process, and is subject to price pressures generated by national or global scale competition. There are exceptions, naturally. Generic drugs or semiconductor chemicals may be commoditized but manufactured by relatively small scale batch processing though still subject to commodity market dynamics.

A commodity chemical product is one which has numerous producers offering similar specifications and varying mostly by price, often resulting in strong competition. As a result of the large scale and the great competition, commodity chemicals are often priced at low dollar-per-unit levels. Owing to the basic nature of commodity chemicals in manufacturing, it is not uncommon for commodity chemical sales volume to be an economic indicator.

Here is an important economic point in thinking about commodity vs non-commodity chemicals. Commodity chemicals typically have a cost structure featuring large raw material or energy costs. Commodity processing is all about the dilution of overhead into high volume. Commodity cost structures may be quite immobilized by fixed raw material and/or energy costs.

Commodity chemicals are commonly used for mass production of other goods. Examples of commodity chemicals include NaOH, soda ash, potash, sulfur, sulfuric acid, HCl, chlorine, BTX, ethylene, propylene, butanol, ethanol, methanol, naphtha, methane, hydrogen, ammonia, etc. These are materials bought and sold by the railcar and whose sales volumes indicate the health and vigor of entire nations. Other, lower volume, chemicals are commoditized as well. Additives and treatment chemicals for commodity consumer goods like pigments, solvents, plasticizers, dyes, food processing additives, lubricants, polymer additives, metal treatment chemicals, agrichemicals, etc. These goods are sold on the large scale for their performance modification or other properties.

Specialty and Fine Chemicals

Specialty and fine chemical products are commonly sold in lower volumes for a broad range of manufacturing and formulation activity. There is no sharp line of demarcation between commodity and high volume  fine chemicals. Commoditization is less a manufacturing phenomenon and more of a market phenomenon. The same is true for specialty and fine chemicals.

Specialty and fine chemicals are an important part of the total chemicals market sector. There are tens of thousands of chemical entities on the market. Most are deeply obscure, in demand only by a few researchers. A common growth strategy of  catalog companies is to increase the number of catalog offerings, thus snagging new customers by providing specialized precursors to those who do not want to make a science project out of starting materials. This business strategy has helped to grow the well known chemical catalogs to their immense size.

A specialty chemical is a material that feeds into a particular use, or is valuable or usable only to a particular end user. Commonly, a specialty chemical may be used for a single application by a single customer or a few narrow applications for a few customers. A specialty chemical is often part of an intellectual property package whose use and identity is highly controlled. The specialty chemical, like a fine chemical, may be covered under process patents that limit manufacturing practices.

A specialty chemical may be of technical grade (i.e., 60 to 95 % purity) or it may be highly purified. It might be of a complex composition and specifiable only under bulk properties like viscosity, flash point, or color. Or a specialty chemical might be highly purified and have sharply defined specs requiring spectroscopy, chromatography, XRD, % ee, or elemental analysis. A specialty chemical might also be a fine chemical in the sense that its composition is in the public domain, but its application is just obscure or covered by a patent.

Generally, a fine chemical is a substance whose composition is in the public domain and is refined to some commercially viable level. A fine chemical may be a reagent or a substrate and may be  used by anyone technically qualified to handle it. Very often, the composition of a fine chemical is understood to a high level. Fine chemicals may be starting materials for the manufacture of other substances, or may be used directly in an application where it remains chemically intact at the retail level.  An example would be an emulsion stabilizer or some polymer additive.

Specialty and fine chemicals are not mathematically distinct definitions. The differeces are based on market behavior and intellectual property. Examples exist which may find a home under both definitions. For the most part, a specialty chemicals manufacturer is a producer of customized materials with a limited base of potential customers.

The Prime Directive

Here is the central business imperative of any chemical plant- we want to run the reaction as fast as possible without taking undue risks. Labor costs and other overhead accumulate with process time, Δt. Any given batch fine or specialty plant has x gallons of capacity available for use 24 x 7 every year. The key to profitable operation is to get maximum product output per unit time. That means maximum space yield and/or maximum rate. Decreasing production time is equivalent to increasing plant capacity.

Production risk divides into two principal domains: 1) safety and 2) economic. While it is possible to have an economic risk without a significant safety risk, the practical fact is that all safety risks are also economic risks. So in the execution of a process improvement, very practical thinking has to guide the work.

Cost Drivers

Commoditized chemicals are often disproportionately raw material or energy cost intensive relative to specialty and fine chemicals. High volume, low margin products that have been in a competitive market a while have most likely been optimized such that the labor contribution to overhead has long been minimized. For a given plant, significant improvements to the cost structure may not be easily found in the labor column if the major costs are raw mats. Except as follows. Relocating a plant to a country with lower labor and/or tax costs. Commodity production follows the labor cost gradient from a high-cost labor pool to a lower-cost labor pool.

Process intensification on chemical products that have been commoditized for a long time is difficult. Besides relocation of the manufacturing site, a step change in processing technology may be needed to improve process economics. Fundamentally new chemistry (or catalyst!) or reactor type or in materials handling may be needed to justify a change.

Whereas commoditized chemical costs may be driven by raw material or energy costs, specialty and fine chemicals are most likely to have a cost structure driven by labor and overhead. A dominance by labor cost contribution will be especially true early in the life of the chemical product. The early developmental period in the market life of a fine or specialty product is the time when competition is likely to be minimal and price pressures lowest.

Early in the life of a fine or specialty chemical product is the time when the end user is struggling to understand the market picture. This is the commercial development period. While the end user (customer) is certainly trying to contain costs, low volume may cause the buyer to rely on a single supplier for a time. This gives the vendor a chance to log enough process iterations to bring the production costs more in line with expectations.

When pricing smaller volume products, every effort should be made to pad the costs in anticipation of process upsets and low yields. And for high margin. R&D and scaleup costs are typically highest early in the life of a product. Margins should be high enough early on so that the early production pays for the development. Customers will not be enthused about this. They’ll want you to “partner” with them and get some skin in the game early. Try to avoid this, politely.

A small volume fine or specialty product should be heavy in labor costs. Over time, and as price pressure from customers mount, the vendor should be able to accept price concessions through improvements in labor contribution. This is wiggle room. A smart vendor will never price a new product too close to raw mat cost since the inevitable movement of price is downward.

Low volume specialty or fine chemicals are often not subject to the same sort of pricing dynamiocs as the commodity chemicals. This category of chemical manufacture is more obscure and the products may not be manufactured constantly or in large lots.

Importantly, lower volume fine and specialty chemicals are commonly purchased on a spot buy basis rather than a supply contract. Owing to the lack of long term certainty of cash flow, spot buy prices are always higher than contract prices.

Process Intensification. The benefits.

The business of making a reaction execute in a shorter time or in a higher batch space yield or batch chemical yield is called process intensification. The idea of intensification is to produce more product per unit batch volume of processing equipment and/or per unit batch time. Every chemical plant has a fixed number of operable reactor gallon hours per year.  Given that conventional chemical batch reactors are fixtures that are very expensive to modify or change out, it is desirable to focus effort on getting the maximum product out of those limited reactor gallon hours.

In a competitive market, one way to grow is to find advantageous economies of scale and pass some of that improvement along in the form of more attractive pricing.  The ability to maximize the throughput of product in fixed equipment is the ability to dilute overhead expenses into a greater number of kgs of product and direct more cash into the profit column.

Process intensification almost always involves doing something faster, hotter, at higher pressure, or in increased concentration. That is the intensification part. An exception might be an alternate process that affords a higher chemical or space yield, or faster rxn rate without undue risks.  One should always be on the lookout for these plums.

Process Intensification. The down side.

The attactive part of process intensification is quite plain. But there is a down side that may or may not be apparent in any given intensification project. It is a change that could bring plant operations closer to the release of hazardous energy.

The question that any process intensification project should squarely address is the matter of the accumulation of hazardous energy. This can be manifested in many ways.

For example, you increase the concentration of your reaction mixture in your process. This is a space yield intensifying improvement that has the benefit of advantageous bimolecular kinetics. You get more product per batch and you increase the reaction rate by increasing the reagent concentrations.  Reagent feed times are nominally increased, but probably not to a deleterious extent.

Naturally, there are consequences to consider. Is there an induction period to look out for? The thermal consequences of this may be magnified at higher space yields.

Does the intensified process produce excessive and unwanted side products?

Does the process generate a precipitate or increase the viscosity of the reaction mass? Increased viscosity has a deleterious effect on heat transfer and mixing efficiency. Slurry formation may be enhanced and consequently produce problems with discharge and pumping of the reactor contents. Filtration may be problematic as well.

Furthermore, as a result of reagent addition the reaction mixture may have a greater density that the initial solution in the vessel, diminishing power transfer efficiency in agitation. Effectively you may end up vortexing an inner band of reaction mass with poor flow along heat transfer surfaces.

Cavitation at the impeller tips may occur and attenuate the efficiency of heat transfer. Heating a viscous two phase reaction mass may lead to localized overheating along the reactor  jacket if it is rigged for heat. I have seen this lead to flash boiling of volatile solvents along the jacket surface with an increase in pot pressure.

Another form of process intensifiaction is through the application of higher reaction temperature and/or pressure. Increasing the reaction temperature could be as easy as using a higher boiling s0lvent. Or it could entail higher pressure as well. Whereas most operations can easily accommodate a higher boiling solvent, higher pressure will require specialized pressure vessels. These are less common, in fact, they are part of a manufacturing subspecialty in their own right.

To summarize, intensify a commodity chemical process is more likely to involve  addressing raw materials, energy inputs, and material handling.  Conversely, while specialty and fine chemical processing could benefit from the above areas of concern, unit labor cost is likely to be a target for process improvement. Labor cost is something that can be minimized most easily by process intensification and quite likely without fundamental equipment changes.

From time to time, all processes should be re-examined for efficiency and safety improvements. But the operator should expect consequences in any process change.

A chemist’s encounter with boneheads and the disreputable

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One of the things that happens to a chemist in the sales department is the business of taking odd phone calls. Someone out there will scan the internets for information on some particular substance or product and find the number of your company switchboard. The person at the front desk  will spend a moment with the caller and then connect them with someone like myself.

During my business development time I have been amused, surprised, pestered, annoyed, and yes, a little frightened.  I have fielded calls from a prisoner wanting expert witnessing (his planned appeal was based on a false premise), illicit drug makers wanting bulk intermediates sent to their motorcycle or chrome shops, and crooked characters wanting items on the MCA list sent to their garage operations.

I am not a member of the law enforcement fraternity. God knows these characters have never asked for my help.  There is precious little I can personally do in the fight against drug crime. But foiling those who would profit from poisoning the nervous systems of our citizens is something that can be done by chemists.

I have spoken with misguided people on the dark side of chemistry who are on the fast track to prison. And, I have taken calls from parents of K-12 students wanting energetic or otherwise hazardous materials for their science fair project. In this case, we’ll have a polite discussion about safety and I’ll offer some alternatives.

I have been yelled at by frustrated foreign nationals for my refusal to quote on items on the munitions list or the State Department’s official shit list of bad actors. Some were persistant buggers, but I extracted satisfaction in interfering with their sourcing plans. The front lines in illegal technology transfer or illegal synthetic drugs is not in the offices of the authorities. It is on the phones and emails messages of companies who sell materials or devices that facilitate the activity.

It turns out that knowingly selling substances to suspicious characters is not only morally wrong or makes you an accessory, but it is just plain bad business. Long term stability for you and your company requires compliance with the code. Selling materials that may be used for illicit purposes by unqualified buyers is only an open invitation for trouble.

Trolling for organizational weaknesses happens all of the time and all over the business world. Industrial espionage, attempts at illegal export/import of controlled materials, and raw material sourcing attempts for illicit or controlled substances. You have to keep your head on a swivel and qualify your customers.  

Trade shows are particularly bad for spying and competitive intelligence gathering. Companies who can afford large trade show booths will have an enclosed room to meet privately with potential customers. That way watchful eyes will have a harder time figuring out what they’re up to.

Few experienced business development people are shy about asking questions, especially yukking it up over a business dinner and drinks. When in doubt about giving information, just shut your yap, shrug your shoulders, and grin.

Always be up front and honest when it comes to withholding confidential information. Even, or perhaps especially, when you have an NDA in place.  You do not want to get in the habit of discussing sensitive topics in social settings. Leave that for meetings in the conference room where your cohorts can participate and everyone can hear what was disclosed. Savvy business people on either side will halt conversation on the spot if they believe that proprietary information is being divulged inappropriately.

As to the matter of gaming the system, I’ll offer that it’s always better in the long run to avoid planting misinformation. It is better to be regarded as uninformed or unhelpful rather than as a liar in the sales world. You can eventually slough off the reputation of being a bit uninformed or rude. But once branded as a liar, even in a field of liars, it is a stink that will follow you for the rest of your career in sales.

Homestake Mine Visit

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The town of Lead, SD, pronounced “leed”, is home to the Homestake gold mine. The mine was purchased and subsequently developed by George Hearst, father of William Randolph Hearst, and partners ca 1876.

Homestake Open Cut from Yates Hoist House

 The photo above shows one ground view of the large open cut found on the north end of town. The pit is approximately 1/2 mile across and 1200 ft in depth from the highest elevation.

The pit exposes the ore body which is comprised of inhomogeneous igneous rock with gold bearing veins. In the photo below the vein structure can be seen. The buff colored rhyolite bands seen below are not associated with value.

Homestake Open Cut, Lead, SD.

Gold was discovered at a surface exposure, called a “lead”, which became the namesake for the town of Lead. Mining activity was halted in 2002, in part due to the low price of gold at the time. By that time the underground workings had reached a depth of 8000 ft, which puts it at ca 3000 ft below sea level. The rock temperature at the 8000 ft level was reported to be 130 degrees F, requiring substantial air conditioning for the workers and equipment.

Hoist Cable

The (poor quality) photo above shows the hoist equipment in the Yates head works. Of interest is the conical cable spool used to provide lift for hoisting operations at the Homestake mine. The purpose of the variable diameter feature of the hoist was to provide maximum mechanical advantage when the cable was at the end of its reach, presumably when it was ready to lift a heavy load of ore from the bottom of the shaft.

Homestake Honey Wagon

The “ore cart” in the photo above was the toilet facility for the miners. It featured a seat on top which could be sealed, a thoughtfully placed foot platform, and railings so the user could hang on for those rough rides.

The surface tour of the mine consists of a trolly ride around town with a stop at the Yates hoist. Warning: It is quite superficial in content, but is the only type of tour available. Our tour guide was student on summer break with near-zero knowledge of the geology or the engineering. He was accustomed to entertaining the barely interested.  If you are keen on the particulars of Homestake history, I recommend Nuggets to Neutrinos, by Steven T. Mitchell.

Homestake was one of the very richest loads of gold in the western hemisphere. Reportedly, some 40 million oz of gold were extracted from the mine.

Today, the Homestake mine is being converted to an underground nuclear physics lab facility under a program called DUSEL. On a side note, it is interesting to listen to the townsfolk talk about the new labs. I could tell they are trying to be enthusiastic, but the reality of neutrinos is very hard to get your arms around.

A bit of sympathy for BP

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I can’t help but have some sympathy for the folks at BP just now. They are not the evil empire and despite their poor safety history, say, the recent Texas City refinery explosion, they do in fact rack up a good many safe operating hours doing very hazardous work. They handle and process flammable materials on the gigantic scale.  And, they respond to market pull for petroleum products.

I have been to meetings in their facilities in the UK and discussed new technology platforms that they wanted to bring on stream. I have listen to a few of their scientists describe their technology and marveled at the new things they have found for molecules to do. They are smart, competent, and well meaning people and we should not lose sight of this.

BP helps to provide the petroleum that we use to conduct out busy modern lives.  We gladly consume every bit of their output. In fact, their contribution to the supply picture helps to keep hydrocarbon prices low. The same is true of all the producers.

The now famous spill in the gulf is clearly a bad thing and it happened to them for several reasons.  But consumers have not responded to this in what you might call a philosophical manner. Nobody seems to be jolted into wakefulness by the depth that producers have to drill to find oil or the fact that these guys are resorting to drilling way out on the continental shelf.  We just plug along expecting demanding that they keep producing at the same price.

If the critics of BP can drill better or operate distillation towers or cat crackers better than BP, then they should get off their duffs and do it. Put up or shut up. The chronic condition we are all subject to is the truism that we can do better.  If you think you can be a better driller, then try it. It’s harder than it looks and it doesn’t look easy.

Needlessly invoking clathrates. BP’s underwater ice machine.

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In the news reporting on the BP oil spill, there is talk of methane/water forming a special ice composition that defeated the previous attempt to channel oil to the surface.  I think folks are referring to clathrate formation. This ice blocked the flow of petroleum from the concrete structure that was lowered over the well head.

But, here is the deal. Wouldn’t you expect cooling of a compressed gas as it exits the well pipe and into the sea water? Isn’t this just an example of the Joule-Thompson effect?  As the natural gas component of the petroleum discharge exits the pipe, it is going to expand somewhat, even at a one mile depth, and cool the surrounding water. If this occurs in unconfined, open water, the jet of petroleum will entrain water in the flow and be warmed by the continuous flow of heat from the water.

But, if the gas/oil mixture of petroleum is ejected in a confined space that interferes with heat transfer, then one would expect the expansion cooling of the gas phase to predominate and cool the water in the confining space, possibly to the freezing point. Clathrates may be formed, but the simplest explanation is from good old thermodynamics.

Minnesota’s fabulous Cu-Ni-Pt-Pd-Au Nokomis deposit

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A world class non-ferrous mineral deposit in Minnesota is on the cusp of opening.  Duluth Metals, a Canadian mining company, has been engaged since at least 2006 in developing its Nokomis property in northern Minnesota along the north shore of Lake Superior. The magnitude of the find is stunning and Minnesota will eventually be synonymous with non-ferrous metals like copper, nickel, platinum group metals, and Norwegian bachelor farmers.  The Duluth complex is part of the second largest mafic intrusion in the world, second only to the Bushveld complex in South Africa.

Mining people are accustomed to looking at these reports and the accompanying prospectus. But it is interesting for we sheltered, begloved, and begoggled chemists to view the birth of a new mining district from the protected confines of our air conditioned laboratories. Perhaps in a few years Minnesota palladium will catalyze your Suzuki coupling.

BP oil spill. What are the merits of using dispersants?

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BP Oil Spill Image, May 4, 2010 (NASA Earth Observatory)

Oil Spill near Mississippi delta. Vegetation, red; Oil, silver. MA 24, 2010. (NASA Earth Observatory photo)

Eventually, BP will find a way to block the discharge of petroleum into the Gulf of Mexico.  And, eventually, the effectiveness of how the relevant parties responded to the incident will be analyzed and findings posted.

I hope that some effort will be put into an analysis of the merits of using dispersants in general and Corexit in particular. What sparks my comment is the finding that considerable subsurface petroleum has been found. This material is evidently close to neutral buoyancy and is drifting with the currents.

Question 1: Is there a connection between the dispersant use and the presence of this subsurface body of petroleum?  

Question 2: What is the desired outcome of dispersant use?  Where did the planners think the petroleum would go?

Question 3: Is there any advantage in encouraging petroleum to remain below the surface, if that is even possible?

At some point, a decision was made to use dispersants on this massive discharge. Is there a scientifically supported rationale for this, or was it palliative treatment intended to mask the surface effects of the release?

Whither Diethyl Ether?

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Diethyl ether seems to be in short supply in North America these days. Suppliers have customers under allocation constraints.  Yes Virginia, people still use Et2O in certain kinds of chemical processing. Sometimes Et2O is prized for its solvent effects and sometimes for its volatility. Sometimes the only way to solubilize some  inorganic compounds is as the metal etherate.  Solvent residues in fine chemicals are often a problem and volatile process solvents can be a big help in ameliorating that issue.  You can purchase 5,000 gallon tanker loads of Et2O if the supplier has qualified you. Another reason not to swerve in front of trucks on the highway. 

Part of the problem with Et2O availability is the considerable reduced demand for it these days.  Many companies have banned the use of Et2O on their site for any purpose. It is easy to understand why. The insane vapor pressure and low autodecomposition temperature are problematic for plant safety. The low boiling point of Et2O means that plant utilities can heat a vessel of ethereal soln rapidly and blow a rupture disk at reasonably low pot temps.  Naturally, the safetly department gets surly about this kind of thing.

Tetrahydrofuran is not always a suitable process stand-in for Et2O. Reactivity behaviors may be quite different from Et2O solns.  THF’s sensitivity to butyllithium, for instance, forces one to keep the processing conditions at low temp with a chiller. Lower pot temperatures increase the thermal margin of safety, but may have a deleterious effect on activation of a transformation once BuLi has done its job. 

I have studied the decomposition of methyl tetrahydrofuran with BuLi and have determined that it decomposes in the low 30’s °C range, somewhat higher than THF. MeTHF is not an exact stand-in for THF or Et2O either.  But it is definitely worth having in the stockroom for development work. It will surprise you in regard to how different it can be from THF.

While MeTHF is touted for its ability to phase separate with water, it will hold appreciable amounts of water.