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Brandeis University's Community Newspaper — Waltham, Mass.

Nonlinear chemi-what?

Published: March 3, 2006
Section: Opinions

Yes, its that time again. Time for another Jeremy Heyman column, and yes, Im going with a Chemistry topic again this time. From past experience Ive learned not to focus on one professor for too long, so no Ozerov or Foxman involved this week. My apologies to the Inorganic Chemists in the audience.

In recent times there have been cases of groundbreaking scientists who are subsequently accused of fabricating their data. As with other types news, the depressing, sad stuff seems to draw all the hype, with the feel-good stories seemingly nonexistent. Yes, we all know of historic cases of scientists whose ideas were cast away during and after their lives, only to be accepted as veritable theory hundreds of years later. Alternately, research directed at a given problem may be found fruitless in that area but extremely important to a completely different scientific discipline. Professor Irving Epsteins (Chemistry) 1998 Introduction to Nonlinear Chemical Dynamics offers a fine example of these phenomena. ( and Wikipedia were also used in constructing this article.)

Alfred James Lotka was born in 1880 in Lemberg (a city in Austria-Hungary, not to be confused with the childrens center or academic hall at Brandeis). His scientific genius erupted in the 1910s and 1920s as he wrote a number of papers about the theory behind chemical oscillations. If that sounds Greek to you, have no fear. It did to me, too, a couple weeks ago. (It always helps a writer when the inspiration from an article comes from ones coursework.) Lotka showed that a series of successive chemical reactions could display oscillatory behavior en route to chemical equilibrium. He also searched for oscillations that obey the Law of Mass Action. (The Law of Mass Action is obeyed by reactions in which the coefficients and order of the reactants are the same.)

Unfortunately for the chemists, the theories Lotka developed in searching for oscillatory behavior from mass action kinetics does not have any applications in Chemistry. The ecology and statistics buffs among us would give an unassuming Chemistry major a harsh slap if (s)he let Lotka go that easily. Ends up that work he did with mass action is a pretty big deal in modeling predator-prey relationships in ecology (as seen in the out-of-phase wavelike variations of lynx and rabbit populations versus time). Perhaps Lotka got tired of his work, however, as he permanently left science to be a statistician for Metropolitan Life Insurance in the mid-1920s.

If you think science lost out with Lotkas exit to the insurance world, allows me to borrow some slangyou aint seen nothin yet. In the 1950s, Boris Belousov mixed bromate and ceric (Ce4+) ions and citric acid together in solution and observed a cycle of yellow Ce4+ converted to colorless Ce3+ converted back to yellow Ce4+. If left unstirred, the solution showed traveling waves of yellow color. He tried publishing his intriguing work in 1951. The editor replied that what he reported was impossible. It cant feel good to have an editor tell you that you made up your results, that your work is impossible based on fundamental scientific principles.
The chemistry community basically thought Belousov was a lunatic. Chemists thought this chemical oscillation work was the stuff of legends. The prevailing idea was that chemical reactions could not oscillate back and forth because this would be the equivalent of a perpetual motion machine, which violates the Second Law of Thermodynamicsthe change in total entropy of any isolated system or of the universe must increase (Δ

Stotal > 0) for any given change of state. Chemists argued that dust particles or bubbles were causing the oscillatory behavior, not a homogeneous (single-phase) chemical reaction. In fact, chemical reactions can oscillatechemical concentrations can oscillate back and forth as long as the reaction is constantly on the way to equilibrium (the free energy of the reaction is decreasing monatomically).

I know were at a liberal arts school here at Brandeis, but this is a case in which we should have listened to the chemical engineers. The engineers knew that homogeneous chemical oscillators were possible based on their work with continuous flow reactors. Too bad the chemists did not have word of this in the early 1950sBelousov worked for six more years on his chemical oscillations paper, only to have it turned down by another editor on the grounds that it was too long. Belousov gave up on publishing, and his manuscript floated freely around the scientific community in Moscow.

The year is 1961. Enter MSU graduate student Anatol Zhabotinsky. Thats Moscow State, by the way, not the school in Lansing, Michigan. Zhabotinsky continued Belousovs work, and ten Russian papers about the Belousov-Zhabotinsky (BZ) reaction would appear by 1967. Zhabotinsky and Belousov were among those honored in 1980 with the Lenin prize for work on this now-famous reaction.

Zhabotinsky is now a professor of Chemistry here at Brandeis. He works with Professor Epstein;

in fact, in the 1970s Epstein and his undergrads were key players in putting some method to the madness of finding chemical oscillators.

The chemist dekes once, twice, Brandeis Chemistryyyy shoooooots and scores!