Category Archives: Chemical Industry

BLEVE- Boiling Liquid Expanding Vapor Explosion

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There is kind of fire behaviour called a BLEVE– Boiling Liquid Expanding Vapor Explosion.  A BLEVE is what happens, for instance, when a closed container of flammable liquid is exposed to strong heating.  It can be caused by an external source, like a pool of burning liquid around the container, or it can result from a runaway reaction within a drum, cylinder, or tank.  The internal pressure builds up more rapidly than it can be vented and the containment fails, often explosively. It is interesting to note from the above link that boiling action of the liquid phase in the container absorbs energy and has a cooling effect, but there may come a point where the vapor pressure rise above the liquid exceeds the capacity of the relief discharge capacity and the vessel fails, discharging liquid and vapor across the burn zone.  At minimum, discharge and ignition will lead to a large flare, or if conditions are right, an actual detonation of the fuel/air mix could happen over a relatively large space.

These things often begin with some kind of tank or tanker accident (link updated 6/10/16) resulting in a discharge and ignition of flammable liquid.  As responders arrive they find a burning pool under or next to the tank(er).  Naturally, firemen and bystanders try to help those who may be hurt. As the minutes tick away and the fire becomes more aggressive and the tank gets hotter, the firefighters get their equipment in place and attempt to cool the tanker and suppress the fire.  Suddenly the tank fails and there is a prompt bulk discharge of liquid and vapor yielding a large fireball which may include an explosive shock, flying metal debris and a dangerous heat pulse.  It is at this point that the surviving bystanders and responders see the error of their ways.

Containers of flammable liquids rarely explode in a symmetric fashion so the container or its fragments are likely to be sent flying at high velocity, possibly spewing flammable material as it moves.  Even a relatively small volume of flammable liquid dispersed explosively can fill a large surrounding space with a fireball.

All chemical plants have their protocols for emergency response.  It is important for those in charge to recognize an incipient BLEVE and respond accordingly.  But even academic chemists should familiarize themselves with the phenomenon.  A fire in the lab engulfing closed containers of flammable solvents is extremely dangerous and very quickly firefighting may become your last earthly act, especially without personal protective equipment.  It is easy to under estimate the violence of these things.

Every lab person needs to look inward and decide what their personal limit is for dropping the fire extinguisher and running for the exit.  In my sophomore organic labs, the seed I planted in the students mind was this: The main purpose of a fire extinguisher was to fight your way to an exit.

Mixing and Unmixing

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Today was take-your-kid-to-work-day.  In honor of this we put on a chemistry show in one of the labs.  Burned some Mg ribbon, shrunk some balloons in LN2, blew up some balloons with dry ice, reduced iodine with ascorbic acid, and we unmixed some NaCl and carbon black. 

One of the barriers to teaching chemistry is a level of physical abstraction that is hard to get around.  It is hard to get around trivial explanations when the audience is not ready to discuss electrons.  Many of the really insightful concepts in chemistry are inherently abstract and age inappropriate for the younger crowd, so to compensate, chemistry demonstrations are often heavy in the whizbang components.  That’s fine.  It should be fun and visually appealing, especially for K-6. 

I like to do mixing and unmixing because it demonstrates something about materials handling.  It also represents an activity that occupies much of our time.  Separation science is not commonly called “unmixing”, but for chemistry demonstrations it causes kids to ponder the problem for a bit.  They all have experience in mixing things- we talk about that.  Then I ask the question “What if I asked you to unmix that KoolAid”?  A few of the more worldly ones might suggest boiling off the water.  But most kids seem to be stumped- they will admit that they would have never considered the possibility of unmixing. 

So we dissolve some NaCl in water and make a solution.  The use of a magnetic stirrer and stirbar makes way for a minor diversion with magnets and iron filings. Then we blend in a bit of carbon black. Using a Buchner Filter, filter paper, and Celite, we do the vacuum filtration, showing the remains of the carbon in the Celite.  The filtrate is then treated with some “Anti-Solvent” like acetone and the salt comes crashing out. 

Yeah, I know. It is pretty tame.  But it can be done cheaply in 45 minutes and the kids can see their parents actually doing something. 

Along Came ChemSpider

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There is a new resource out there called ChemSpider.  In the few searches I’ve had a chance to do, it seems to be pretty efficient at separating a lot of the wheat from the chaff that you’d get just using Google.  It would be interesting to hear what others think of it.  According to the informative FAQ page, ChemSpider is a highly specialized chemistry search engine.  And, did I mention it’s free?  Yeah baby.

To begin you enter a name, CASRN, tradename, synonym or SMILES. This generates a report of hits. Click on an ID number or a structure and another page brings up hotlinks to various resources on the web. Click on the Data Sources link and another page will come up with a variety of data sources and their unique external ID numbers. Click on the molecular formula link and it pops off a Google search of the formula.

Obviously, this isn’t the same as a SciFinder search- you don’t get access to journal downloads and article bibliographies.  It connects you to a variety of public access sites that appear to be data repositories and collections of commercial suppliers.  But it is a real improvement over a raw Google search.  You don’t get the rats nest of links to publishers (i.e., Wiley, Elsevier, etc), expired colloquium notices, or literature citations from curriculum vitae on faculty websites.  

It will convert names to structures and, using ACD/Labs software, generate calculated physical properties.  I would be hesitant to enter the identities of confidential materials just yet. I do not know if they compile entries into a database or not.  I’m not convinced that I would enter a sensitive confidential material on it until I had a chat with an attorney about the question of disclosure.

All in all, it seems to be a useful tool for web searches.  I have only scratched the surface of what this thing will do.  Give it a try and see what you think.

First Class Tickets to Stockholm

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The buzz has begun for the 2007 Nobel Prize in Chemistry.  Over at ChemBark a list of fields and potential awardees is presented.  Odds are offered.  It is interesting to ponder.  In case you were wondering, the identities of the awards committee for 2007 is actually published.

When the committee calls for my opinion, I’ll have to set ’em straight.  First I’ll scold a bit about the snub of some early workers in asymmetic synthesis and how they were overlooked in 2001. People like Henri Kagan for C2 symmetric ligands among other things and Kurt Mislow for basic contributions to stereochemistry.  The guys who won in 2001 were deserving, but the omission of Kagan and Mislow is a shame.

I would like to see some organometallikkers like Suzuki, Heck, and Sonogashira get the recognition for their contributions to coupling chemistry, but I’m not sure it is a Nobel Prize body work.  I would prefer to see Bergman , Whitesides , or Harry Gray get the trip to Sweden for their fundamental contributions to organometallic and bioinorganic mechanism work. 

There is my free advice to the commitee.

Chemical Plant Production Managers

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I have known a few plant production managers at several facilities in my career and they seem to share particular attributes. No doubt they fall into a particular Myers-Briggs type.  I can say without a doubt that I am personally disqualified from such activity because I tend to be more of the absentminded professor type.   It takes a certain breed of cat to manage any kind of production facility.  Indeed, your average construction site superintendant is probably better suited to manage a chemical plant than is a chemist. 

Well, OK. That was a bit harsh.  Many chemists could do it if they had to. But if you owned a chemical company and were looking for a new plant manager, you’d probably find that the pool of candidates didn’t include many chemists. There, that is more polite.  Chemists are often tweakers by nature and a chemical plant is not a place for experiments. Plant managers live by the production schedule. They are both masters of and slaves to this schedule.  Their whole careers are about the coordination of material flows- the arrival of raw materials, processing, and the logistics of shipping.

A chemical plant is a big machine through which flows a large stream of money.  Money flows in one side of this machine and out the other side.  Jets of cash flow outward to payroll and raw material vendors. The production manager never forgets that the inflowing stream must always be bigger than the outflowing stream.  Customers insist on just-in-time delivery of products, but they also want 60 days net with a lot of other strings.  The relationship between the controller and the plant manager may be chronically strained.

People who run production plants are really engineers, irrespective of whether or not they hold a diploma in engineering.  Scientists find the thread between cause and effect.  Engineers take that thread and figure out how to use it for fun and profit. Sure, some scientists have engineering sense and some engineers have scientific sense.  But a plant manager is all about running the plant at full speed. When they make tweaks, it is usually on the engineering side.  Usually they are loath to alter chemistry.

In the Navy they have a saying- Fight the Ship.  Use every part of the boat to your advantage.  Slap ’em with the rudder if it comes to that.  A good production manager is crafty, thrifty, and when needed, a brutal task master.  He knows his crew and can and will push them to the edge when needed. 

A really smart plant manager will find and keep the best maintenance people he/she can find.  In fact, a savvy plant manager will always vote to throw a chemist overboard rather than let a maintenance person go.  One of the least acknowledged groups at a chemical plant is the maintenance crew.  To keep the plant up and running you need the skill sets of plumbers, welders, pipefitters, machinists, electricians, iron workers, carpenters, tinners, and a bunch of general handymen and gofers.  Usually you hire people with multiple skill sets.

The best plant managers are steely-eyed SOB’s who speak softly and command respect and maybe a little fear. A plant manager must be able to work effectively with arrogant executives, stubborn accountants, egghead scientists, angry admin staff, defensive production people, and sly construction contractors.  The people skills are as important as the technical skills.

If I were going to hire people for key management positions in a plant, I would hire people from the nuclear Navy. As a group, they have already been screened for many attributes useful to a chemical plant. They tend to be high achievers, have good quantitative skills, have been highly trained for work in hazardous environments, and they understand the importance of following protocol.

GD vs ICP Mass Spec

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I wonder if there are any mass spec jockeys out there who can comment on the relative accuracy of Glow Discharge Mass Spec (GDMS) with ICP Mass Spec (ICPMS)  at the ppm level?  In other words, if one has data taken from each and compares them side by side, which should one side with? I have results from both analyses on a metal oxide and I’m puzzled as to which I should stand behind. 

If you have one clock, you know what time it is. If you have two, you’re never sure.

One lab breathlessly proclaims that GDMS is linear over 9 orders of magnitude, but is subject to 20 to 30 % error owing to a lack of a valid standard (??!@#?). The same fellow says that ICPMS is accurate to 5 % at 100 ppm, but the error is considerably higher at 1 ppm. Good gravy.

No doubt, the answer will contain the words “it depends”.  But I wonder what the issues are. 

The Zen of Hazardous Materials

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My first experience with truly hazardous materials was in 1981.  It was a sophomore organic lab and we were making sulfanilamide.  Using chlorosulfonic acid, we attached a ClSO2 group in the para position of acetanilide.  Pedagogically, it was a very rich experience because it validated the idea of O,P-directors, protecting groups, medicinal chemistry, and offered real experience in the handling of hazardous materials.  And, at least as corrosive materials go, they don’t get much more obnoxious than chlorosulfonic acid.

The preparation of sulfanilamide was an excellent lab experience because it brought home some fundamental truths about nature.  Namely, that physical and chemical properties of matter can be “tuned” and tweaked by people to give a desired outcome.  For students, this lab experience connects the inorganic, inanimate world of the periodic table to something closer and more personal.  It gets to the very nanomachinery of life itself.  It is a glimse of how drugs work. It gets right to the pointy end of the stick- Drugs are about selective toxicity. 

Once you have taken the time to gain some understanding of how drugs work at the molecular level, you are forever changed.  One begins to realize that biochemical “mistakes” can happen naturally and are part of the game.  Suddenly, the world is full of rogue “isosteres” and “pharmacophores“.  You can no longer accept blithe generalizations about toxicity and chemical hazards.  There is truth in the First Law of Toxicology- Dose makes the poison.  Your working definition of toxicity takes on new forms, like the notion of endocrine disrupters. 

As time goes on and my view of the natural world becomes increasingly molecular in scope, I find that my working definition of what constitutes “hazardous” has skewed a bit as well. Hazardous does not automatically equal “bad”. The modern material world is now a swirl of substances synthetic and substances natural.  Industry has given us dioxin and nature has given us aflatoxin.  But at worst nature is indifferent; human activity can be negligent or even malevolent. 

A mature view of hazardous materials must simultaneously accomodate physical/chemical reality with certain norms of conduct, with prompt and delayed biological effects of hazardous materials, and with consequences to the biosphere.  In truth, modern society must use hazardous materials to produce goods and services vital for healthy living.  But we chemists must find ways to limit the number of moles of hazardous waste we generate. Especially the persistant substances- metal salts, halogenated hydrocarbons, etc.

Synthetic chemistry relies on reactive materials in order to do bond making and bond breaking.  There really is no getting around the need for reactive materials. But we can find ways to generate reactive materials in situ.  Reactive intermediates are generated in a catalytic cycle and used on the spot.  More pervasive use of catalysis could be a contributor to lower generation of haz waste or a greener chemistry.  This is just a corollary to Trost’s Atom Efficiency concept.

Hazardous materials have a utility that is similar to a knife.  A knife is a tool that does a very useful thing- it cuts. Every single time you pick it up you have to be wary of the edge and the point.  It is a persistant hazard.  But we continue to use it because of it’s utility.  In a way, chemicals are the just like that.

Professors and Their Patents

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I had the occasion to have a conversation with a very prominent chemistry professor this week.  He has many hundreds of publications and many, many patents.  The fellow’s name would be familiar to many.  As such characters tend to be, he was overflowing with ideas and enthusiasm. His energy was evident from the precocious stream of insights and commentary that flowed from his gurgling fountain of knowledge.  

But something he said in passing caught my attention and for a moment halted my petit mal seizures resulting from overexposure to his relentless rhapsody of intellection and hypercogency.  He chimed that not so long ago his University had been passively collecting a stack of patents generated by its faculty. They had been in no particular hurry to do anything with the IP and had only recently started to take an interest in it. He made a furtive attempt to strike a spark of interest in his patents and when met with silence, quickly retracted it back into its sheath.

In my travels I have encountered professors who have made faint reference to their patents, say, during a poster session, in the manner of weary gentry casually mentioning an obscure parcel of prairie in Oklahoma.  Interesting, but yesterday’s news.  Sort of a publication, but … not really. Not all profs have such a casual view of patents, however. 

<<<<<< A snarky sentence was removed>>>>>>> …  Apparently he was patenting most everything that spewed from his labs.  Every permutation- methyl, ethyl, butyl, … futyl- was carefully covered by complex Markush claims so as to anticipate even the most clever work-around.  It makes one wonder how such research groups are properly managed. Do you have an IP group and a public domain group? Should people doing the IP work be paid more?

What raises my hackles about university patents is this: As a result of the Bayh-Dole act, universities can be assigned patents to inventions that were funded by federal tax money.  Superficially, it sounds like a decent idea.  It sounds like it might facilitate technology transfer. What’s wrong with that?

Well, let’s see.  A patent confers 20 year monopoly rights to the assignee (rarely the inventor) for a process and/or composition of matter.  One obtains a patent in order to enjoy protection from infringement, or unauthorized use. In the case of a university, just who do they need protection from?? The public who paid for the research leading to the invention? 

What kind of public policy is this?  Public monies are disbursed competitively in the form of research grants which funds the research.  The public pays for the bricks and mortar to keep the wind and rain off that new 600 MHz NMR in the new wing and for the journal subscriptions in the library.  The public has to pay for the patent prosecution and the trips to ACS meetings to give a talk about the work (though rarely is there a mention that a patent is pending).

The public has to pay Chemical Abstracts Service for access to bibliographic information and copy fees or journal subscriptions or download fees to access the information.  For a business to use the invention, a license agreement has to be negotiated and in all likelihood, will have to pay a fee upfront, well in advance of the first dollar of sales, and submit to annual audits.  With any given patent, the University Tech Transfer Office may have already issued an exclusive license to someone else. In that case, tough luck.

Granted, some of the more IP savvy schools reap decent royalties from some fraction of their patents, i.e., MIT & CalTech.  But I would say that they are in the minority. Most patents just consume money, not generate it.  These unexploited patents merely serve as a barrier to the public who are trying to get product to market.  It is quite easy for a chemist to reinvent a compound or process that has been claimed by someone else already.  It is bad enough when it is your competition. It really stings when you are barred from practicing art that you unwittingly helped to pay for.

Let me sponge up the bile and make room for others to comment. What do you think about this issue?  I’m probably just full of hot air.

Note: This is a revised post, with minor content editing. 

Chemists and Chemical Engineers

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What an awkard pair, these chemists and chemical engineers.  To strangers from a distance they might appear almost interchangeable.  Someone from another field might assume that the differences could be as inconsequential as minor variations in accent or hair style are between neighbors.  A simple matter of preference for the practical or the arcane. But that someone would be wrong.

Chemists and Chem E’s are really quite different by training and by disposition.  We chemists think of our field as resting upon the three pillars- Theory, Synthesis, and Analysis.  Chem E’s will agree, but they’ll point out that there is a 4th pillar- Economics. 

Here is an act of convulsive reductionism:  Atomic and Molecular Chemistry (as opposed to Nuclear Chemistry), the science we normally think of when we use the word “Chemistry”, really concerns itself with the behavior of electrons near positive point charges. When we cause a chemical change we are perturbing the disposition of electrons somewhere. In doing so, ensembles of nuclei and their electrons connect, disconnect, or otherwise alter the disposition of the electrons.  Chemists make and break bonds, transfer electrons, or promote electrons to particular energy states.  This work is limited to the outermost layers of the onion. We rarely ever have to consider the inner layers of electrons and we never monkey with the nucleus.

Chemistry is very much an electronic activity. It is the realm of electronic quantum mechanical formalism and machinations at the Angstrom scale. Virtually every chemical change we do involves the twiddling of electrons somewhere.

Chem E’s, on the other hand, practice applied classical physical chemistry.  Unlike organikkers such as myself, they took a serious fancy to P-chem. Their quantum unit is the dollar. These folks can actually put thermo to use for fun and profit. They understand the sacred and profane applications of the gas laws. Chem E’s can specify what sort of pump you need to move whatever variety of hellbroth you care to convey and they can probably estimate the Reynolds number of the rainwater running off your nose.  A Chem E can tell you what kind of materials of construction and seals you need to reflux thionyl chloride in your reactor and what kind of chiller capacity you need to condense it. 

And as engineers, they can plan a construction schedule, work up a cost estimate, and supervise the construction of whatever kind of process equipment you care to specify from the dirt up.  A chemist could probably do it as well, but it would look like a chemist did it.  I have personal experience here.

You probably wouldn’t ask a Chem E to synthesize vitamin B-12.  But they wouldn’t ask a chemist to design a continuous fractional distillation column either.

Chemical Blogometrics

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I see that according to Chemical Blogspace, my Gunning-Fog index has gone up a notch- from Al Gore to Thomas Pynchon.  Oh, good gawd.  Now I have to worry about that as well…?

Forty thousand years ago all you had to worry about was a sabre tooth tiger dropping out of a tree on you, or those nasty Neanderthals up the river raiding your camp, killing your women and raping the men. Today we have secretive organizations applying these odd metrics from the dark recesses of the blogosphere. Who are these people? And, what do they want? 

Actually, what they are doing is quite interesting. It provides good feedback for bloggers. Once we wipe away the tears we can improve our “product”.

All this talk coming from a guy who writes under a pseudonym \;-)