Long Live the Intermediate!
What’s in between in a reaction matters just as much as what sets it off
Of Myths and Money
The catalyst’s hold on our imagination is not, of course, solely a matter of laziness. I see several reasons that it may fascinate us more than its paired reaction intermediate.
Magic: In the workings of a catalyst there seems to be something special, even mythological. The catalyst, often precious, is lost—and then returns. The phenomenology here connects with the archetypal cycles of the Earth, as expressed in our mythologies and religions. Think of Phoenix rising from the ashes, of Persephone’s sojourn in Hades and her periodic return, of reincarnation, of resurrection. Indeed, it took some decades to move from the alchemical conception of catalysis in the 19th century to the mechanisms we know today. Still, the wonder remains. A catalyst is magical, and loses none of its magic if we know how it works. How could a reaction intermediate compete? It is not resurrected; it just fades away. Its detection, no matter how ingenious, has at best the feeling of a satisfying detective story.
Lucre: Part of the wonder of catalysis—like that of alchemy in earlier centuries—is the promise of riches. If a catalyst can make go a desired yet recalcitrant reaction—a reaction that is essential for the production of a compound with a market—and if it makes that synthesis more efficient than that of competing companies, that catalyst is valuable. Most, if not all, industrial processes involve catalysis, and one tries to protect these compounds with patents. They are essential intellectual property. But I have a feeling that not every important catalyst is patented. Because small amounts of matter can be catalytic, and their action so specific, it may be simpler to keep the real catalyst as an unpatented trade secret—with the attendant dangers of it being stolen, or worse, discovered independently and patented by a competitor. You can wait to find the intermediate after you discover and patent the catalyst. Actually, could you even patent an intermediate if you wanted to?
Serving humanity: Humans are moved by selfishness and altruism both. The fact that half of the nitrogen atoms in our bodies have seen the inside of a Haber-Bosch factory is not only certification of profit for the companies involved; it is also a statement that twice as many people are alive today as would be if there were no such factories producing ammonia fertilizer. Organic agriculture could take up some of the difference, but in my opinion, not close to what is needed. Catalysis feeds the world.
We usually think of catalysts as good because they give us more of what we want (such as fertilizer). But the world doesn’t care for our values. In its natural or unnatural processes, it catalyzes reactions we don’t want (decomposing ozone, spoiling meat), just as often as those we do.