Last August, the comments on this page saluted recent achievements of BASF Corp., Merck, Archer Daniels Midland and other winners of the U.S.’s 2005 Presidential Green Chemistry Challenge Program, administered by the Environmental Protection Agency (Green-chemistry feats bring in the gold, CE, August 2005, p. 7). In light of today’s high interest in, and the clear desirability of, such usage of chemistry and chemical engineering for pollution prevention, it makes sense to complement those well-merited salutes by also glancing at several green-chemistry/engineering goals that still remain to be widely met. At a Philadelphia meeting of the Chemical Heritage Foundation’s Joseph Priestley Soc. late last year, a challenging review of such goals was presented by Paul Anastsas, director of the American Chemical Society’s Green Chemistry Institute.
Up to now, he points out, companies’ typical response to environmental regulation has been of the circumstantial variety — for instance, lessening the human exposure to a dangerous substance. But an approach that is instead intrinsic, (for instance, employing molecular design) can be not only more reliable but also less costly. Anastas cited several goals and targets in this vein. Among them are these:
• Can, and will, we design molecules and synthesis paths whereby as much as possible of the raw material(s) end up in the final-product molecule?
•Can we employ solvents that also serve as catalysts, and that can be easily separated downstream?
• Can we design molecules that remain unreactive until they arrive at a moment and place of our choosing?
•Can we harness relatively weak forces, such as hydrogen bonding and pi interactions, to become design tools to impart product-performance capabilities and to control the reaction pathways?
•Can we employ single instruments for carrying out nondestructive multiple analyses?
•Will we ensure that chemistry and chemical engineering students learn the importance and value of targets and goals such as these?
Encouragingly, numerous green-technology issues are currently emerging, Anasatas added. Among these are ones that relate to nanotechnology, to solvent systems (for detailed guidelines on solvent selection, see pp. 30–43 in this issue), to process intensification, to workforce training, and to green-chemistry metrics and protocols.
In perhaps another indicator of green-chemistry momentum, the 2005 Nobel Prize in chemistry went to three persons (among them the honorary research director at the Institut Français du Pétrole) for application of the metathesis chemical-reaction concept to organic syntheses (CE, November 2005, p. 18), The prize committee noted that metathesis is efficient, simple and environmentally friendly, and represents “a great step forward for ‘green chemistry’.”
Aside from minimizing pollution during production, green chemistry can be a weapon for firms aiming to innovate their products so as to fend off commoditization. An example cited by Anastas involves producing pigmentfree color via light refraction.
Contrary to what is sometimes believed, the number of environmental regulations is not tailing off, notes Anastas. But, he adds, green chemistry can render those regulations irrelevant.