The Parable of Adipic Acid

But I can’t believe that any group which is rooted in the principles of freedom and service can have gone very wrong.

C. M. Kornbluth, The Syndic, 1953

Pantyhose, whose semi-ethereal protein-like* substance had the ringing name nylon 6,6, was derived from two chemicals: hexamethylene diamine and adipic acid. Let us briefly consider the latter:—a water-soluble, sour-tasting crystalline white solid with a melting point of 303.8° Fahrenheit. (Reader, I hope that your mean surface temperatures remain below any such figure.) Have you heard of that inconspicuously influential substance? Sometimes we called it hexanedioic acid. Each molecule contained 10 hydrogen atoms, four oxygen atoms and six carbon atoms.

Being a peachy-keen feedstock for synthetic lubricants, urethane foams, plasticizers, you name it, it sprang into commercial importance in the 1940s. Food grade adipic acid is used to provide some foods with a “tangy” flavor, and justifiably so: After all, its aqueous solution could corrode certain steels.—In the mid-1990s, 3,500 tons a year went for “food acidulant” in American jams, jellies and gelatins.* It must have been good for us, being one of the purest materials produced on a large scale.

Now, what else could we do with it? (In other words, how could we muck up some ecosystem somewhere?) Heating it comprised the best route to cyclopentane and its derivatives, whose profitable uses I shall spare you. In that process, clouds of carbon dioxide got “lost”—but only to our atmosphere. As our decider President used to say, “Bring it on!”

Most of it was destined for nylon. What a treat to watch adipic acid* combining with the hexamethylene diamine so that we could see a pallid syrup forming, settling out into something resembling melted cheddar cheese! Making use of the way that carbon links to itself, and even joins chains to chains, thereby thickening into those long strands which, as pantyhose should, resist oxidation and bacteria, industrial magicians deployed what they called “the nylon rope trick”: Polyamide produced at the interface may be pulled continuously from the open vessel in a startling demonstration of polymerization chemistry.

Each pound of nylon cost “only” 18,700 BTUs of power or heat—awfully close to the innate energy of a pound of fuel oil—but, as I keep on reciting, our power plants had to burn three pounds to do each pound’s worth of thermodynamic work. So, a pound of nylon required three pounds of heavy heating oil, which sent up 10 and a half pounds of carbon dioxide. That was just the beginning.

There was nylon in the hose of my air compressor, nylon in my father’s fishing line. The 1956 Sears, Roebuck catalogue couldn’t stop pimping it out! Reader, would you like a Cordtex brassiere? Nylon styles are lined with beautiful nylon sheer and stitched with nylon thread. This lining in underbust offers extra support. (How lovely!) And for outerwear, why not Gleaming Rayon Velvet?

NOTHING STARS in the firmament of evening fashions like the glowing loveliness of jet black velvet . . . it’s the epitome of glamour when topped with an exotic hood and lined in immaculate white—the body of the lining in nylon fleece, the sleeve lining in rayon and acetate velvet.

In short, we had no choice but to continue making adipic acid.

I once met an elegant high-ranking Japanese geisha whose wardrobe largely consisted of her grandmother’s handwoven silk kimonos. The fabric looked new; the designs were unfailingly beautiful.—Rarely did nylon “intimates” show any such durability, either of style or of physical integrity. The panties in the photo below were fading more with each wash. Their owner had begun to tire of them. That was as it was supposed to be. As an article in Resources, Conservation and Recycling concluded:

All current economic systems are predicated on growth and . . . it is almost impossible to imagine a different system emerging . . . [B]usiness models in production companies are oriented towards growing sales volumes, so are strongly motivated to . . . build in “planned obsolescence” to product designs. Thus, material efficiency . . . will . . . be opposed by . . . businesses unless they can reclaim value through some other activity.

Undies made in Thailand and sold in U.S.A. (82% nylon)

To be sure, this might have been bad news for our climate—but, reader, don’t glare at me like that! It was wonderful news for adipic acid.

We made so much of the stuff that it sometimes got shipped in 200,000-pound hopper cars. (Don’t you call that success?) By 1990 a 130,000-ton manufacturing plant had been announced for Western Siberia. Another was up and coming in South Korea. The continued buildup of capacity in nylon-6,6 intermediates, especially in the Far East, attests to the confidence in continued growth by the major participants.

Adipic acid was another of those marvel-chemicals which not only offered myriad profit-making applications but could be produced in any number of ways—from cyclohexane, or cyclohexene, phenol, butadiene, whatever, as dictated by shifts in hydrocarbon markets. (It also emerged in automobile exhaust, but since we had not yet figured out how to collect and sell that form of it, we simply emitted it, mile after mile, entirely gratis—and up it went. Fortunately, it was invisible.)

In our chemical factories, no matter how or from what we made our adipic acid, there came a moment when we needed to oxidize its hydrocarbon precursor in nitric acid.

As you have read,* producing that already generated nitrous oxide. Now the nitric acid must be put to work.—Adipic acid manufacture reduced it to nitrogen dioxide and nitrogen oxide—which could both be captured and reconverted to nitric acid—and to pure nitrogen—which was harmless—and, most relevantly, to what has been called “considerable” nitrous oxide. Up it rose.

In 2007, adipic acid production emitted (in carbon dioxide equivalents) 0.55% of Germany’s greenhouse gases.*

Once again, any reasonable know-nothing might protest that 0.55% of a nation’s environmental misdemeanors was so trivial that our attention should have been spent on more conspicuous culprits such as fuel combustion. (In the Appalachian chapter you will hear a lobbyist say: “You can shut all 12 hundred coal-fired power plants down in this country today and you will effectively reduce less than 4% of CO2 emissions.”)*—One might argue that since Germany’s manufactures of adipic acid had released three times more nitrous oxide in 1990 than in 2007, the latter figure should even be celebrated. At first, even I believed that, back when I was alive. Any decrease in waste, or increase in efficiency, which to my mind comes close to the same thing, is inherently good—and round about 1993, German chemists had invented two new ways of decomposing almost all the nitrous oxide into oxygen and nitrogen. Why not be glad when anything got done? To be honest, I could not blame that coal lobbyist for expressing frustration toward government and environmental “activists.” “That’s where I have a disconnect with the President and the EPA,” he told me. “I do not buy the statement that the U.S. must demonstrate leadership. I think we have been providing leadership throughout my entire adult life!”*—And so I felt grateful to Germany for “providing leadership” in decreasing adipic acid’s nitrous oxide emissions. It had not even been 20 years yet since the most progressive nations (not mine) had signed the Kyoto Protocol, and this fable promised well: In one country, for one category of activity, one kind of greenhouse pollution had been reduced.

Now for the sad part: Considering industrial process emissions as a whole, Germany admitted defeat, as a result of “economic trends.” And what could anyone do about those? To date, a counter-trend has been achieved only in the case of N2O emissions. It is the result of emissions-reduction measures by adipic acid producers, measures that took effect as of 1997. And yet that trend as well is being increasingly offset by production increases.