The world would be a greener place if we derived all the chemicals our industries need from plants. These so-called agrochemicals are generally biodegradable and far less toxic than chemicals derived from oil (petrochemicals), and they are renewable, which means we'd never run out. Unfortunately, agrochemicals cost too much to produce.
Rathin Datta, a chemical engineer at Argonne National Laboratory, has taken a small step toward bringing costs down, at least for one type of agrochemical. Lactate esters, solvents made from cornstarch or sugar, could be widely used in semiconductor chip manufacturing, in stripping paint and de-inking paper for recycling, and in household cleaners and degreasers if only researchers could find a way to make them cheaper than their present price of $1.60 to $2 a pound. The problem has been that conventional processes for making the lactate esters are very inefficient, largely because they lack a good means of separating out the by-products and keeping them from interfering with the reactions.
Then Datta heard about "pervaporation" membranes, which can be used to separate chemicals with small molecules from those with big molecules. After experimenting for two years, he found that with these membranes he could effectively derive his agrochemicals from a broth of fermented cornstarch rich in ammonium lactate. Using heat and catalysts, he first breaks down the mixture into ammonia and lactic acid. Ethanol already present in his brew then reacts with the lactic acid to form the lactate ester. All this time, the membrane lets the water and ammonia by-products escape but keeps the other, active ingredients together in the chamber.
