Sy mposium From the chemistry of responsible environmentalism to environmentally responsible chemistry
Environmentally Sustainable Growth in the 21st Century The Role of Catalytic Science and Technology James A. Cusumano Catalytica, Inc., 430 Ferguson Drive, Mountain View, CA 94043
Nations of the world face an unprecedented and daunting challenge. They aggressively seek to stimulate their economies, to create new jobs, to increase the accessibility of products and technologies that enhance the quality of life-and a t the same time they desperately pursue the reversal of a perceived global environmental crisis. Resolution of this apparent paradox can be addressed to a significant degree by new developments i n catalytic science. With the recent advent of molecular design techniques, the modernized form of this broadly applicable technological tool has the potential to change the face of the four fundamental needs of humanity-health care, food supply, energy, and materials-and to do so in a way that provides a path to environmentally sustainable development for all citizens of the planet. The Challenge Sir Winston Churchill, admiring the power and potential of science, once exclaimed:
Humanitv stands todav at its most fateful milestone On the one hard wenre opens up a chasm of self-destructron beyond Iirolira O r , rhcorhcr hand ~hcdisplqso\.ision ofplenty a n d corntun o f w h i c h rhc rnnsscr of no mot- h a w rvrr known or even dreamed Never have these words had more to say than today, a s we prepare to enter the next century. With the close of the 20th millennium, we have come face to face with the paradox envisioned by the great English Statesman. On one hand, society, governments, and industry seek economic growth to create greater value, newjobs, and a more enjoyable and fulfilling lifestyle. Yet, on the other, regulators, environmentalists, and citizens of the globe demand t h a t we do so with sustainable development-meeting today's global economic and environmental needs while preserving the options of future generations to meet theirs. How do nations resolve these potentially conflicting goals? By the middle of the next century, the worldwide Gross Domestic Product (GDP), which is a measure of prosperity and ~roductivitv.is nroiected to be five times lareer than i t is toiay. From the b&ning of recorded history ;ntil1900, i t grew to $600 billion. I t now grows this much every two years ( I ) . Today, it is a t $16 trillion and climbing ( 2 ) . Society h a s exacted marvelous benefits during t h i s growth. In the United States, life expectancy has increased from 50 years of age in 1900 to almost 80, today (3). This achievement of greater longevity, a s many other achievements during this period of explosive growth, is due in large measure to advances in science. Specifically, contributions from the disciplines of physics, chemistry, and biology have enabled the design, synthesis, and manufacture of therapeu-
tic molecules that have nermitted u s to successfullv, address moat of the physiolu~:cal threats of the 20th century Even meetine the challcmar of the AIDS virus is within reach. ~ e s u l t have i been remarkably similar in other areas that impact our quest for a higher quality of life. Ironically, we have paid an environmental price for this progress. I n 1993, in the United States, the chemical industry produced more t h a n 350 million tons of toxic waste-more than 10 pounds per person per day-which was safely disposed of a t a cost of $20 billion ( 4 ) . Even with waste minimization methods, this annual level of toxic waste is projected to grow to more than 500 million tons by the year 2000 and will cost more than $40 billion for proper disposition. I n other areas, we have not been as effective i n remediation. We have experienced a significant increase in airborne NOx, SOx, COz, and tropospheric (surface) 03. These emissions have led to parallel increases i n ground-level smog and acid rain. In China, more than a half million sauare miles of forest is under assault bv acid rain ( I ) . I t is not surprising that by the year 2000, the annual U. S.exnend~turcfor clwn un of'S02as a means ofcontrollincrac~d ;sin will reach more 'than $7 billion. By the middle of the 21st century, the population of our planet is projected to douhle to more than 10 billion people, and the corresponding GDP will reach some $80 trillion (5). The reality of these projections may be appreciated when one recognizes that every second there is a net increase of three persons on the planet (5).This is approximately 250 thousand people per day or 94 million per year-equivalent to reproducing the population of Mexico, the 11th largest country, every year. About 90 million of these 94 million people are from less developed countries, and for the most part they expect to achieve the same standard of living a s those of us living in developed nations-and why shouldn't they? The question is, how do we reconcile these two apparently disparate factors: economic growth and sustainable development? This may be the most critical technological issue we face as the human race. I t is no longer simply an economic question, nor is i t just a n environmental question. It is an enviro-economicquestion. And it is one that can be addressed by the science and technology of catalysis.
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The Motivation
The U. S. chemical industry is typical of the large waste generators i n the world technology markets. I t releases approximately 1.5 billion pounds of Toxic Release Inventory into the environment each year (6).In 1990, total emissions of about 4.8 billion pounds were released into the air, water, and land by all manufacturers i n the United States. Volume 72 Number 11 November 1995
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Although these amounts are lower than the corresponding 1987 amounts, the chemical industry remains the largest single source of pollutants. The cost to this industry iucreases substantiallv each vear. I t should, therefore, not be surprising that the chemical industrv i n the United States bears one of the lareest shares of total pollution control expenditures-approximately $4 billion in 1992 (6).One fifth of its new capital expenditures is allocated to pollution abatement or control. Decreasing these exoenditures bv the use of cleaner more cost-effective catalytic technolo"gies would address the issue of sustainable development as well a s provide a definitive competitive advantage to those companies practicing these technologies.
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Proposed Strategy The reduction of chemical waste in the U. S. chemical industry has leveled off, partly because industry has made the most of the easier, low-cost changes. Most of these approaches have used "end-of-pipe" strategies. This has been recognized by industry and government alike a s not sufficiently effective, to reverse the current environmental trends of concern. Instead, industry is moving to pollution orevention. This is bv far the most economic strateev and the technological pa&digm necessary to enable nat& of the world to increase economic growth while maintaining environmentally sustainable development. Catalysis will be central to this strategy as it enables society to address its four basic needs-health care, food supply, energy, and materials-with cost-effective methods that encompass a commitment to environmental sustainability (2).The reasons for this are twofold. First, catalytic science and technology are pervasive in our society and necessary to produce critical goods of commerce. I n t h e United States, approximately 20 percent of its GDP, or $1trillion worth of goods, require catalytic processes for production. This encompasses foodstuffs (e.g., artificial sweeteners, margarine), pharmaceuticals (e.g., I-dopa, vitamin C), energy (e.g., gasoline, fuel cells) and materials (e.g., plastics, fibers). The second. and eauallv im~ortant.factor derives from major developm&ts over tlcrafts catalysts such a s AIC13 will"provide imp&ant economic and environmental benefits. The development of a new process for the production of 2,6-diisopropylnaphthalene(2,6 DIPN) provides a good example (22). The 2,6 DIPN, formed by alkylation of naphthalene with propylene, is a n intermediate that i s oxidized t o t h e corresponding 2,6 dicarboxylic acid a n d subsequently polymerized with ethylene glycol to form hightemperature engineering elastomers-called liquid crystal polymers. The older process used AlC13 a s the catalyst of choice. Unfortunately, it is just as easy to form the undesirable 2,7 isomer as well a s waste tri- and tetra-alkylated naphthalenes, all of which must be separated and disposed of a t a cost. Furthermore, spent AIC4 also forms large volumes of waste that are costly to treat. The catalyst is not regenerable and is corrosive. New orocesses use crvstalline.. shaoe-selective zeolites . such a s molecularly engineered mordenite that acts a s a sha~e-constraining"molecular reactor." The zeolite Dermits primarily theiormation of 2,6 DIPN that can be selectivelv discriminated bv its size. even though i t is onlv tenths of an Bngstrorn B m a ~ ~than e r the larger 2,7 isome; The new process easily doubled the vield of 2.6 DIPN from 35 to more than 70 percent. This catalytic requires less expensive product/catalyst separations, produces lower amounts of waste, fewer byproducts, and is a catalyst that is regenerable and non-corrosive. The enviro-economic consequences are significant.
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Catalysis in Fine Chemicals and Pharmaceuticals The opportunity for catalysis i n fine chemicals stems from several changes i n the dynamics of the pharmaceutical industry. First, there is increasing economic and politi-
cal pressure on pharmaceutical companies to lower the prices of their products. I n part, this means lowering manufacturing costs by increasing the yield of the desired Droduct i n a manner that is environmentally' acceptable. The environmental challenges are great iecaus;, i n the ~ a s tthis . industrial sector was not com~elledto be as efflcient a s other chemical sectors such as*petrochemicals or petroleum refining. In the latter two markets, i t is common to minimize waste to less than 0.1 lh per pound of product. This i s critical because of the large volumes of materials processed i n these commodity areas. But in pharmaceuticals, because of multistep batch processing and a generally more forgiving economic situation, i t is not unusual to produce more t h a n 100 l b of waste per pound of products, clearlv room for sienificant environmental imnrovement. Interestingly, the primary reason for the relatively higher environmental efficiency i n petrochemicals compared to ~harmaceuticalsi s the much greater use of catalytic proc. . issing i n the former. An example of how catalysis can cut the cost and environmental waste i n a fine chemical synthesis is exemplified hv new technolow -" (23)to oroduce the anti-inflammatory, ihuprofen. Until recently, the prevalent technology started with p-isohutlyacetophenone and required three major steps using hazardous reagents. The p-isohutlyacetopheneone i s reacted with HCN and AlEt3 to form the cyanohydrin t h a t then i s reacted with CH30H a n d suhsequently hydrogenated in NaOH to form the sodium salt of R,S ihuprofen. R,S ibuprofen is formed hy the reaction of the sodium salt with HCI. The new technolow -" starts with the same raw material hut eliminates the hazardous reagents and cuts the nnmber of steps in half, from four to two. The p-isobutlyacetophenone i s hydrogenated over a Pdlcarhon t o p-isobutlyphenyl-alpha-ethanol. In the second step the alcohol is catalvticallv carhonvlated with a Pd(I1) catalvst directly to R,S ibuprofen. ~ h enviro-economic k benefits are i k roved sienificantlv over the older technolow. -" There is also a growing need for optically pure drugs, ~articularlvwhen one recoenizes t h a t 88 Dercent of all svnthetic optically active drugs are sold a s racemic mixtures. In a real way, ingestion of a racemic drug may he viewed a s in uiuo "isomeric" pollution because only one isomer is therapeutic and generally the other is, a t best, neutral and sometimes toxic. This was notablv the case for thalidomide, a drug prescribed in Europe during 1959-1960 a s a sedative for .rea an ant women. Unfortunatelv. .. when ingested during the early stages of pregnancy, the drug resulted i n severe birth defects due to the teratogenic characteristics of one of its isomers, S-thalidomide. The Food and Drug Administration (FDA) continues to develop increasingly stronger guidelines for optically pure products.
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Creating Environmental Sustainability through Catalysis Through the application of catalytic science i t is possible to envision a vast array of future catalytic products and nrocesses. Although orornostication is eenerallv the mobus operandi of astrologists and soothsayers, Lelow the author has hazard a listing uroducts and orocu of soecific . esses, important to address the critical needs of society for environmental sustainahility, and which, i n his view, are achievable through the methods of modern catalytic science within the stated time frames. Ten.. 20- a n d 50-vear milestones have been chosen against which to measure progress. These products and orocesses. either directlv or indirectlv. address the comhihation of'economic growth and environmentally sustainable development. Though not complete, this list is meant to stimulate thinking as to what could be achieve if desired
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and if adequately supported by a n effective partnership of government, industry, and academia.
2000 AD
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Catalvtic combustion aoolied . . to stationam. and mobile sources tor pollurion-free power l%~ocotnlvtic rcmo\nl ofsulfur, nitrogen, and mctals from pcrrolrum 1'~nctinns Exlmsvr ";it. uf vstalyiu in fine rhemruals producuonftmnat~anifootwallv uure chml unrductj and mlnlmmmun of hazardous caw m&&ials and toxic byproducts Large pore molecular sieves for shape-selective chemicals synthesis New environmentally benign CFC substitutes Alkene-to-alkanefeedstock transition for petrochemicals [extensivecommercial use of selective alkane functionalizatianl In-situ techniques for observing catalysts "in action" and user-friendly molecular graphics and quantum mechanical programs, bath powerful new methods to support the molecular design of practical catalysts Safe solid catalysts to replace hazardous liquid acids such as HF, HzSO,, and HNO, Extensive use of fuel cells as stationam Dower sources
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metallocene catalysts
Commercialization of an economic, direct methane-to-liouids~ .lant Economically viable photocatalytic splitting of water to Hzand 0, Synergistic multifunctional catalysi-nzymes, inorganic and organometallic catalysts in the same system Therapeutics from small molecule catalysts; engineered enzvmes and catalvtic antibodies used commerciallv in chemicals production High-temperatureinorganic-organic polymers Use of COz as a raw material for chemicals production Extensive use of membrane and other multifunctional catalytic reactors for mare enviro-economic combination of reaction with maduet seoarations Supr~nmleculurcatalysis, ndrcdlar imprirniug, and mdrl recognition sysrems i n pharrnoccuricnls Advanced pdyulrh mater~ulscontamn,: pdar monomeric units Protein engineering of enzymeb in microbes (pathway engineering of cascades of linked reactions) for chemicals oroduction
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Broad penetration of the hydrogen economy-fuels and chemicals Composite polymers to replace mast metals and alloys Shift from alkanes to renewable bio-feedstocks for chemicals Chemicals produced in living plants
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Summary The chemical industry will undergo a paradigm shift in which the cost of the environment will he included more included in the process and project economics for a new product. Society will invoke the concept of enviro-economics. Economically superior processes will he based on pollution prevention. I t i s this approach that will resolve the current paradox of apparent conflict between the simultaneous drive of nations of the world for economic growth and their quest for sustainable development.
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Catalysis will be a key to meeting this challenge. I t will play a central role in enabling sustainable development in the 21st century. If properly supported, catalytic science can bring about significant developments over the next several decades. These developments can address the critical needs of society in health care, food supply, energy, and materials. If properly executed, they will profoundly immove our overall aualitv of life. Catalvtic science and techLology has the potentid to bring about these changes in a wav that addresses the concern of Count Antoine de Saint~ x u ~ eauthor r ~ , of "The Littie Prince", who said, We have not inherited the land of our ancestors;we are borrowing the land of our children.
To move in this direction, as scientists we must first imasine a world where pollution is never formed-and then we must create such a world.
6. Cusumano, J. A. CHEMTECH August 1992, p 482. 7. Cusumano, J. A. 'Creating the Future of the Chemical InduptwyCatalysts by Molecular Design" in Chemistry for , l i p 21st Cenfury-Persp&iuss in catalysis: Thomas, J. M.:zamaraey K I., E d s ; Blackwell scientific Puhlicatians: landon. 1992, p 1. 6. Seherer. V.; G r i f f h T. ASME Joint International Power Generation Conference, Phoenix, AZ,October 2-5, 1994, paper 94JPGC-GT-1. 9. Quick, L. M.; Kamitomai, S. Promdings of Inlrrnofionol Workshop on Cukdyl~c Combustion; Chemisfw Hall, Tokyo, Japan, April 18-20, 1994, Arai. H..Ed. 10. Dalla Betta. R. A.; Schlatter, J. C.; Nickolas, S. G.; Yee,D. K ASME. lnternstionsl Gas Turbine and Aeroengine Congress and Exposition, The Hague. Nethedands, June 13-16.1994, P a p r 94-GT-260. 11. periana. R.A.;Taube.D. J.; Eritt,E. R.;Lomer D. J.:Pa"l R. Wenfreek. P R.:Voss, G.: Maouda, T Scienes 1993,259,340. 12. Petiana. R. A.:Taube. D.J.;Taube,H.;Evitt, E. R.U. S. Patent5.306.655 1994. 13. Esposito. A,Ne" C.; Buonomo, F. European Patent 0,102,655, 1984. 14. Romano, U.; Eaposito, A ; Maspero. E: Neri C.:Cletid, M. G. Lo Chim, ondL'lnd. lsBO,72.610. 15. Dmoni. D. P.; Pielii, D.; Tnfim. I?; Tvaruzkova.2.:Haberrherger. H.: Jim. P C d d . Lett. 1991.11.285. 16, Kreage, C. T.; Izonwicz, M. E.; Roth, W J.; Vsrtuli, J. C.; Beck, J. S. Nature 1994,
Literature Cited 1. Heaton. G.; R. Repetto. R.: Sobin, R. Tmnsfonning l k h m l o g y An A w t d o f o r E ~ ~ i mnmrnrolly Sustainable Gmlufh in the 2lsr Ceniuly: World Resources Institute, April 1991. 2. The 1992 lnfwmofion Please Enuimnmanfal Almame, Hammond, A, Ed.; World Resources Institute. 3. The U n i u m a Almonoc; Wright. J . W., Ed.;Andrews and MeMeel: New York. 1992,
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