Monthly Archives: August 2011

ACS Denver Last Day

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I’ve spent much of my time at the Denver meeting talking to vendors in the exposition.  There were some very good pieces of equipment at the show. One company had a GC the size of a sub sandwhich.  Pretty cool. It’s for on-site work and actually comes in Army green and camo. I wish I could remember the name.

The Agilent ICP/MS is truly amazing.  Sub part per trillion capability.  The system uses something called the “helium collision mode” to exclude polyatomic cations from the mass analyzer.  You know those pesky argon chloride cations from sample plasma, right?  The argon polyatomic cations can mimic heavier elements by virtue of their combined atomic mass.  The instrument has an octapole chamber with helium in it that serves to impede the larger polyatomic cations. Clever monkeys.

 

Confessions of a Country Boy

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After much thought I have decided to come clean on the matter of the supposed inherent goodness of growing up rural. I was born to Iowa corn and hog farmers in the late 1950’s.  This business of supposing that growing up on a farm magically confers a kind of wholesomeness is based on some faulty assumptions:  1) Farms are wholesome environments untread upon by people corrupted by the incessant Bacchanalian orgy of wanton excess found in the city. This is plainly wrong. Farms and farmers are just isolated. Modern conveniences get to farms later because of the isolation. Farmers are exposed to pathogens and insecticides in the course of their work. They often get mangled in unspeakable ways by their equipment. Farmers would party like brain-damaged test monkeys with everyone else if it wasn’t such a long ride into town.

Misperception 2) Growing up on a farm brings one into better harmony with nature.  This is wrong as well.  Farming is about the conquest of nature. Farmers know alot about nature, but take it from me, people who plow the ground, churn in soil amendments, and neutron bomb the insect population are not nature lovers. They are nature conquerors.  Farming is about return on investment. Just watch Ag PhD if you don’t believe me. Hey, I watch this show- it’s pretty interesting.

Misperception 3) Growing up on a farm is peaceful and soothes the soul. Well, it seems outwardly peaceful. This is true. And that can soothe the soul. But consider that the prolonged lack of intellectual stimulation has a dulling and isolating effect that prevents people from finding a whole spread of achievement that is possible in the modern world.

Misperception 4) rural life is good because people know each other. You know the guy who owns the CO-OP and the family who sells the home grown eggs. Folks pull together when times are tough.  Well, maybe. The Gaussian distribution of saints and knuckleheads applies everywhere. In a rural community you just know the saints and knuckleheads who farm. Farms have produced Ed Gein and Dwight Eisenhower. Less pathologically, people in rural communities are just as frequently unhappy with their lives as those in the city.  It’s faulty thinking to conclude that the farming or rural life imbues some special merit to a person.  As always, your life story is about what you put into it. I would offer that rural life is less than good because people know each other.

The notion that a politician with a rural history, or one displaying an outward appearance, is invested with a more nuanced sensibility than some city slicker is also faulty thinking.  You can manipulate people with the “aw shucks, ma’am” act as effectively as with the tools of a cosmopolitan confidence man.  In fact, the country boy approach may be more persuasive.

Denver ACS Meeting

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Just back from Day 1 at the Denver ACS meeting.  Spent the afternoon at the INORG session celebrating the 50th anniversary of the journal Inorganic Chemistry.  As usual, Harry Gray stole the show with his talk- today it was on oxo complexes. What I like about Gray is that he shows the younger members that being socially constipated is not manditory for success in chemistry.  Maybe it’s his delivery, but after a Gray talk I leave feeling like I have gotten a glimpse of the future.

Attendance is down a bit due to hurricane Irene.  Looks like the Atlantic coast dodged the bullet. Earth quakes, hurricanes … what next? Cane toads?

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.

Astronomers talking about matter again

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I’m always a little skeptical when I hear astronomers talking about specific compositions of matter out in the universe.  The recent gushing press release from Reuters about a diamond planet orbiting a neutron star just adds to my burden of disbelief. 

I truly hope there is more evidence than that revealed in the press release. That is, the assignment of the diamond allotrope of carbon based on density (3.53 g/cm3).  The report seems to express amazement that the planet is “so dense”.  A specific gravity of 3.53 is not that high. Many other compositions are possible.  Perhaps Reuters should look at high density objects closer to home.

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.

Unfortunate trigonometry and dynamic blind spots.

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Near miss on the highway last night. I averted a high speed T-bone impact by a meter or two as Music from the Hearts of Space played on the radio. Good gravy- I was crashing to space music.  My Cherokee is quite stable in an emergency braking maneuver moving straight forward. But if swerving is required, then vehicle sway begins to couple into the steering. Never thought of this control problem before.

Imagine you are sitting at a stop sign waiting to turn left onto a 4 lane highway. To your left is a deceleration lane for traffic moving left to right.  Now, imagine your line of sight as a line extending from your eyes across your left shoulder and into the distance.  Got that?

Now, imagine a car in the deceleration lane on your left slowing to make a right turn at your intersection. A line can be drawn from your eyes to that car. As the car moves toward you, the line extending from your eyes to that car sweeps clockwise across the landscape. Still with me?

Now consider this.  There exists a third vehicle (me) moving from left to right exactly along your line of sight, but behind and eclipsed by the vehicle in the turn lane. As the turn lane vehicle slows down in preparation for a turn, the third vehicle is at a distance and speed such that it continues to remain along the sight line yet remain eclipsed by the turning vehicle.  As the turning vehicle approaches, it’s angular size increases, obstructing even more space behind it.

That is the condition I was in last night. The perversity of trigonometry allows for a set of velocities and alignments that presents a dynamic obstruction of view to evolve.  If the driver at the stop sign grows impatient and attempts to cross the two lanes of traffic before the vehicle in the turn lane completes the turn, he is doing so on the assumption that the blind space is clear. Last night I was in that blind space while an impatient driver pulled in front of me. 

As the driver pulled out, he saw me and hesitated in my (right) lane, causing me to apply heavy braking and to swerve around his rear and away from oncoming traffic. Fortunately for all of us, he stepped on the gas and got out of the way. With the sway of my vehicle with the maneuvering loads, I was on the verge of a loss of control and may have hit him anyway. 

It is interesting how a steady state cruise along the highway can evolve into a complex set of events in just seconds.  In fact, I had anticipated this problem of visibility as I approached the intersection. I disengaged the cruise control and began to decelerate when I saw that the waiting vehicle could not see me. I now think that my deceleration kept me in the blind spot even longer, aggravating and tightening the coupling of the event.  I was barely able to avoid this failure mode even though I was aware of it.  That is scary.

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.