The last 20 % of the reaction

It’s common for a kinetics study of a reaction to focus on the first 5 % to say, 20 %, of reaction completion. Usually the study is done at high dilution as well. There are good reasons for this. Ideal solutions are best approximated at high dilution and interferences are not nearly so pronounced. The basic science behind the interaction between reactants can be teased out from the early course of the reaction.

For those of us in the chemical synthesis business the imperative is somewhat different. Our concern relates to the extent to which the reactants go to completion.  In commercial synthesis the desired outcome is to maximize the space yield of a process in the available equipment.  That means that work goes into determining the maximum concentration of reactants and getting the highest yield in the shortest time. The material state in the reactor near the end of a commercial run is quite far away from the conditions one would choose for a kinetic study.

Getting to reaction completion is sometimes rather difficult and may involve whiling away plant hours for the reaction yield to get just a bit closer to the asymptote.  The problem is that the remaining 5, 10, or 15 % reaction completion may consume considerable plant time and bring opportunity costs. Near the end of the reaction the reactants all trend to infinite dilution, so of course the reaction slows down.

Often reaction completion is not simply about getting higher yield. Purification may be greatly complicated by a reaction mass that contains remaining reactant. If chromatography is not an option then one is left with the usual methods of bulk purification. As we all know, some materials crystallize poorly out of a messy solution. This is where the plant chemist has to cancel all appointments and grind through the workup scheme.

I would say that semi-batch reaction completion problems can be a serious matter for a process chemist or engineer.  This is especially true with new processes but older processes can surprise you. My advice is to throw resources at it early. There is a tendency to get the run behind you and move on.  It’s best to work out a detailed analytical profile of the reaction mixture and strive to understand what the components are and what causes their appearance or disappearance. Sometimes changing the stoichiometry helps. Getting to completion and finding a clean work up is where the plant chemist really earns his pay.

Nehru Lab Wear

It seems that my idea of flame retardant Nehru lab coat has gotten absolutely no traction at work. It’s a pity.

Nehru lab coat with breathing apparatus.

A few sentences relating to Power

Power is as power does, or the fact of power is the act of power.

Just a reminder. In the fable of the emperor’s new clothes, what is important to understand is not that an emperor can be highly delusional. The real lesson directs your attention to the ease with which those around him facilitate his delusion.  This is an insidious condition that creeps in silently like a fog that soon envelops everyone. It takes a child-like innocence of perspective to see through it. Regrettably, child-like innocence is rarely encouraged in organizations.

Power is in the ability to allocate resources. A successful business person must excel at accumulating and centralizing the power of resource allocation.

Business power stems from centralized control by a few. Representative democratic power is granted by voters.  What is behind the fascination with setting up a businessman in a legislative or executive power position? Business is inherently non-democratic.

The 2012 Albert I. and Joan Meyers Symposium

The 2012 Albert I. and Joan Meyers Symposium will be held on the campus of Colorado State University in the Behavioral Sciences Building, Room 131, on Saturday, October 27, 2012, beginning at 8:00 AM.  Details can be found at the website.

What a Meth Lab is Not

It is time that someone questions the use of the phrase “meth lab”. Just as a cook would object to the phrase ”meth kitchen”,  those of us who spend our careers in the laboratory should push back on the use of the word “lab” in this manner.  The use of this word confers the notion that a workspace is fitted for chemical handling activity and is operated by someone who knows what they are doing. Dubbing a meth operation as laboratory surrenders too much credit to the operator. These people are moonshiners skulking around on the periphery of society.

A meth lab is not a lab. It is the workshop of a criminal enterprise where unscrupulous people manufacture a dangerous substance. Its sole purpose is to profit from the uncontrollable neurological train wreck of methamphetamine addiction. This is not laboratory work. It’s just crime.

Fulminating Belief and the Drake Equation

It seems to me that the character(s) who produced the YouTube video that has caused so much religious fulmination in the sandy parts of the world ought to be parachuted into Cairo to answer for their actions. Surely they can give the best explanation of what their movie represents.

Another thing has occured to me. Perhaps we should make a minor adjustment to the Drake Equation which describes the number of civilizations in our galaxy with which communication might be possible. The equation can be found at this link.  The L factor defines the length of time a civilization releases detectable [radio] signals into space. Given the self destructive behaviours of beings capable of generating radio signals on at least one planet, maybe it is time to define L*.

L* = L(1 – P*/P) where P = average number of intelligent inhabitants of a planet and P* = average number of intelligent inhabitants willing to die/kill for their magical or political beliefs.

Perhaps the reader has a better modification.  Here is the Drake equation copied straight from Wikipedia:

where:

N = the number of civilizations in our galaxy with which communication might be possible;

and

R^* = the average rate of star formation per year in our galaxy

f_p = the fraction of those stars that have planets

n_e = the average number of planets that can potentially support life per star that has planets

f_ℓ = the fraction of the above that actually go on to develop life at some point

f_i = the fraction of the above that actually go on to develop intelligent life

f_c = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space

L = the length of time for which such civilizations release detectable signals into space

Good science requires testing

I found this cartoon over at High Power Rocketry.

[There was no citation for the art work.]

General remarks

I wish to make a few remarks on current news items of interest.

Country singer Randy Travis was found in a ditch in north Texas allegedly drunk, naked, and belligerent following an apparent one car accident.  Crimony! It’s that awful Nashville music that he sings. If I sang that twangy, mornful, depressing stuff all the time, I guess I’d be sloppy drunk in a ditch too. He should dry out and switch to show tunes or something a bit more cheerful.

It seems that while the televisions and internets of the world are busily dulling enchanting us into the delusion that our ever accelerating consumption of resources and expansion into wild spaces are having no effect on the “natural world”, the global ecosystems are actually in trouble. I emphasize natural world only because so many of us are preoccupied with the on-line world. In fact, many are worried about a “state change” in the global ecosystems.

In Approaching a state-shift in Earth’s biosphere, a paper just published in Nature, the authors, whose expertise spans a multitude of disciplines, suggest our planet’s ecosystems are careening towards an imminent, irreversible collapse.

Earth’s accelerating loss of biodiversity, its climate’s increasingly extreme fluctuations, its ecosystems’ growing connectedness and its radically changing total energy budget are precursors to reaching a planetary state threshold or tipping point. [ The Automatic Earth, August 6, 2012. ]

I know, I know. Sounds like Chicken Little. But we should pay more attention to our small planet. The atmosphere is thinner than most people think, the fisheries are stressed, desertification is happening in Africa, and human population pressures are mounting in many locations.  We can’t keep the extractive industries going forever. We need to find an economic model or culture that allows us to do with less mass. Reduced consumption per capita. Look, it’ll happen anyway as key resources dwindle.

We should be aggressively recycling lithium, gallium, tellurium, indium, and the rare earth elements in particular.  These are key elements in our much beloved electronic devices. There are other materials to watch, including hydrocarbons in general.  A society with infrastructure causing one to hop in the SUV and drive 5 miles from their isolated subdivision to buy cigarettes and beer is a society that is on a rendezvous with destiny.

Thoughts on crystals, symmetry, and perfection

Bismuth crystals on my desk

Nothing too unusual here. Just some bismuth crystals sitting on my desk. A metallurgist friend died recently and his family passed along some of his samples to me. Virg was a great guy. He knew how to conduct himself with decorum like a civilized human being. I don’t confer this praise on everyone.

Bismuth City

I think many people find some kind of solace in the orderliness of crystals. Nature has seemingly betrayed the prevalent trend of disorderliness to produce a latticework of pristine stuff in appealing shapes. Crystals appeal to our innate desire for symmetry and rectilinearity. We subconsciously associate symmetry with goodness and calm. Properly stacked goods in your basement suggest orderliness. Shoes lined up in the closet or socks neatly arranged in the drawer provide a reassurance that something in life is at least predictable.

Crystallinity infers a repetitive array of subunits asssembled under the austere constraints of efficient stacking. It represents subunits held in confinement and subject to limits on motion.

Crystallinity is in a sense sterile and lacking in diversity. Living things are not crystalline for the most part. Crystallinity is static and devoid of the many necessary degrees of freedom needed for life.  Living things often have superficial symmetries, though on closer inspection something inevitably cracks the symmetry. Humans have a bilateral symmetry across a line taken from the head to between the feet, as do butterflies and hippos. Internally, though, the symmetry is less than obvious.  Our genetic polymers of DNA have a gross secondary helical symmetry as do some peptides, but even that yields to partial symmetry when the monomeric units are accounted for.  Sure, there are instances of crystallinity in living things. But living things require a fluid internal environment to allow molecules to collide and react.

If you take crystallinity as an allegory of perfection in the sense of a way of being- that is, orderliness and freedom from defects- then you might conclude that a perfect being would be constrained by symmetry or the attributes of perfection.  It would seem that the attribution of perfection in a being might pose the possibility of limitation.

Instead of getting wrapped around the axel philosophically, perhaps we should gladly rejoice in the lack of perfection in ourselves and the ultimate absurdity of perfection in the fanciful dieties whom we imagine control the vibration of every molecule in the fleas that ride on the tailfeathers of every sparrow.

Curiosity on Mars

Photo of Curiosity during descent phase, taken from orbit. This shot is amazing all by itself.

Curiosity in descent phase. Photo taken by NASA’s Mars Reconnaissance Orbiter. Credit: NASA/JPL-Caltech/Univ. of Arizona.

Curiosity is powered by a Pu-238 oxide thermoelectric generator. The Multi-Mission Radiosiotope Thermoelectric Generator, MMRTG, has an output of 2000 watts thermal and 100-120 watts electric. The MMRTG unit sits in the aft end of the rover enclosed by a finned heat exchanger.