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chem I fupplement
MICHAEL R. SLABAUGH Weber State College Ogden, Utah 84408
Chemicals from Wood and Other Biomass Part I: Future Supply of Organic Chemicals David W. Goheen Pioneering Research Group, Central Research Division, Crown Zellerbach Corporation, Camas. WA 98607 The Organic Chemical Industry Industrial organic chemistry, which forms the basis for modern industries of great size, influences the lives and welfare of people virtually everywhere in the world. People have generally come to take for granted synthetic fibers, plastics, dyes, adhesives, drugs, and a host of other products. A world without these products would, for the present generation, be difficult to imagine. I t is thus, a t once, sobering and even disturbing to contemplate the development of thk industry, its present position, and the world's resources of organic materials. Taken in toto the organic chemical industry is a petrochemical industry utilizing almost entirely raw materials derived from fossil reserves of carbonaceous gases and liquids extracted from relatively accessihle deposits in the Earth's crust. Exploitation of these reserves has been a bonanza for everyone and has built mankind's living standards to heights unimaginable only a few generations ago. Accumulation of fossil reserves while undoubtedly still continuing, is painfully slow. The reserves, which we are now consuming, took millions of years to accumulate. Their depletion, in very marked conle will he comtrast, has been and for the f ~ r ~ s e e a b future paratively rapid. The development of the industrial organic chemical industry up to very recent times has heen orderly and can he traced as a rational progression from modest beginnings. During the period immediately following the onset of the industrial revolution early in the nineteenth century, organic chemistry became recognized as a distinct division of chemistry, unique hecause of carbon's ahility to bond to itself to produce myriad combinations. However, even as late as 1856, little was known of structures of even the most simple organic compounds, although the existence of isomers was recognized. Empirical formulas were the only tools available for characterization of complex molecules. Uses for organic chemicals were virtually non-existent. Coal tar from heating of coal was known hut about its only practical use was for fuel. Benzene was known as a product that could be produced from coal tar hut even its structure was uncertain. it was extracted only in small amounts and was consumed to a slight extent as a solvent and as an illuminant in oil burnine limns. The heginnings of industrial organic chemistry can he traced to a chance remark of the ereat oreanic chemist. A. W. Hofmann, who was a professor Englah's newly fomded Roval Collene of Chemistrv. Earlv in the decade from 1850-60. duiing oneof his lectures; ~ o f k a n remarked n on the possi: bility of preparing quinine from an aromatic amine. One of his students, William Henry Perkin, was a young man of 18 at the time. At the tender age of 15,vounn . - Perkin had entered the college and progressedto the point where by the time he was 17, he had hecome an assistant to the nreat Professor. With an amazing combination of confidknce and naivete, "
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Perkin set about to synthesize quinine by the oxidation of allyltoluidine, which according to its empirical formula could be converted to quinine by the loss of one water molecule from two molecules of toluidine. Needless to sav, auinine was not obtained by the oxidative reaction. undaunted by this failure, Perkin decided to investigate the oxidation of the simpler amine, aniline. This gave a black precipitate from which a few percent of a purple material was isolated. Recognizing the purple compound's possible value as a dye, he sent it to a fabric establishment who sent hack a report with favorable comments on the new dye's fastness andiight stability. This more or less serendipitous discovery of the first synthetic dve was the event whichled to the establishment of an aniline dye industry. In the years following the discovery of synthetic dyes, both Perkin and the synthetic organic chemical industry prospered and flourished. Perkin achieved Knighthood and recognition of his contributions to industrial development. The industry grew and other synthetics were added to the list of products that could he made for an ever expanding market. Feedstocks, which a t first were based on coal tar, became more diversified and for a long time both fossil reserves (coal and petroleum) and renewable materials (wood, cellulose. starch) were used to supply organic molecules necessary for conversion to factory-made products. Coal tar played a prominent role, and for many years coal tar chemistry was virtually synonymous with synthetic chemistry. Destructive distillation of wood was also a major industrial chemical process. In this way, acetic acid, methanol, wood creosote, and charcoal were produced. As the industry grew, it became apparent that nature had
This feature presents relevant applications of chemistry to everyday life. The information presented might be used directly in class. posted on bulletin boards or otherwise used to stimulate student involvement in activities related to chemistrv. Contributions should be sent to the feature editor. Mike Slabaugh received his BS degree in chemistry at Purdue University in 1965 and his dgctorate in organic chemistry at Iowa State University in 1970. His interest in biochemistry and natural products research (alkaloids) led to a year of postdoctorai study in biochemistry at Texas ABM Universily in 1971 Dr. Slabaugh is now Professor of Chemistry at Weber State College. where in 1979 he was i recognized as the "Professor of the Year." His professionai interests and goals are directed toward chemical education and community involvement in science activities. He has been particularly active in directing regionai science fairs.
Volume 58
Number 6
June 1981
465
stored a nlentiful s u.. n ~-l vof versatile omanic - molecules in huae . pools of petroleum. In certain countries, and particularly the IJnited States. these fossil accumulations were easily accessible geographically, easy to reach by relatively shallow drilling and were accompanied by immense quantities of natural gas that was even easier to convert to fuel and chemical products than was liquid petroleum. Thus, just prior to World War 11, the petrochemical industry came of age. Ways of producing a host of products from fossil gas and oil sources were investigated, and these developme& continued a t an accelerated pace during the War years. Following the war, pent-up consumer demand for chemical ~ r o d u c t screated an enormous market. T h e demand was met by construction of huge petrochemical plants which utilized nlentiful, cheap, . . and easyto-convert oil and natural gas. As the cost benefits from construction of ever larger petrochemical plants were realized, the use of feedstock fr>m&ul and renewahle hinmasssources dwindled. Hy 1970, almost all solvents, plastics, and adhesives, and amajoi portion of fibers for conversion to fabrics were produced from either natural feedstocks. Truly, there seemed to be no end gas or to the hounty that nature had provided All duringthe period of conversion of chemical feedstocks from coal and biomass to a petroleum and natural gas base, society was deve! ping an even more voracious apetite for conversion of the same materials to energy. Space heating, industrial Dower. consumer electrical demands. and internal ~.~ combustion engines required enormous amounts of clean, low oollutine combustible materials. Maior shifts in enerev -- pro. duction occurred so that coal, with all of its environmental problems both in its production and its combustion, assumed a much diminished role as an energy source. Low prices for natural gas and petroleum were taken for granted and encouraged the shift. The low prices also discouraged development of alternate enerav sources. As one looks hack (only a decade or so!) to this period during which petroleum became so ruthlessly exploited, it is difficult to wmprehend that most of society either ignored or was unaware of the simile attributed to the famous nineteenth century chemist, Mendeleyev. He has been reported to have stated that burning petroleum for energy could he likened to burning bank notes in a stove to keep warm. Many years ago, he, a t least, recognized that petroleum should he much more valuable for its content of ihemicals than for its content of energy obtained in an irreversible manner by combustion. The chanee over to an enerw and materials economv based almost exclusively on gas and petroleum, in a historical sense, took place rapidly. Whole lifestyles, which required ever increasing amounts of energy and materials came about in the developed countries in a few decades. Indications of future troubles were present but, strangely enough, received only small consideration. Little attention was paid to the fact that US. consumption of petroleum exceeded U S . production for the first time in 1966-67. T h e difference was made up by importation so that by 1971, 25% of U S . requirementswere imported.' The figure increased by about 5% each year so that by 1973-74, nearly 40% of the oil used in the U S . was imported. I t should he remembered that this was still inexpensive oil, although i t should also he remembered that OPEC had been organized some years earlier and had already tried to initiate some very modest crude oil price increases.
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Goheen. D. W.. Paper Presented at the 73rd National Meeting. AIChE. Auaust 27-30. 1972. Minneaooiis. MN. ~ditorh."Facts and Figures of ihe Seventies,'' Chem. andEng.
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Shapro. I. S.. "Resouces of Organic M e r faUw Futue." (Edifor St. Pmre. L E I . Multi Science PublicationsLtd Monbeal. Canada. 1978. p. 27. Hubbeft. M. King, in "Resources of Organic Matter fathe Fuhre." (Editor: St. Piwre, L.E.), Multi Science Publications Ltd.. Montreal. Canada. 1978, pp. 58-98.
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Journal of Chemical Education
Few events in modern times can be pinpointed more preciselv in their effects on our industrialized societies than the oil embargo imposed by the petroleum producing countries of the Middle East. Within a matter of a few weeks during and following the so-called Yom Kippur war of October 1973, as industrialized countries realized their dependence on lmported petroleum, long-standing downward trends in energy and chemical feedstock costs were abruptly reversed. Petroleum costs began to rise rapidly, and have continued to do so with resulting confusion, hesitation, and alternating periods of growth and economic recession combined with inflationary price increases. Despite the huge price increases for petroleum feedstocks, the chemical industry has managed to grow and, at times, even prosper. During the decade from 1970 to 1980, the output of chemicals and synthetic materials in the United States nearly d o ~ h l e dThis . ~ haooened even thoueh crude oetroleum ~ r i c e s during the same &;iod rose a t least i5-fold. w h a t can bekade of this seemingly incongruous hehavior of the industry? Part of the answer, and perhaps the whole answer, is the value added to the raw material hv chemical technoloev. As I. S. Shapiro, President of the ~ u ~ bcompany, n t has p&ted out. oil is worth five times its crude orice when converted to polymers and plastics, ten times as much when made into fihers, and one hundred times as much if converted to aaricultural chemicals or photosensitive materials such a s x - r a y films? Fossil Chemical Reserves
Utilization of the finite fossil chemical reserves then represents a dichotomy that has presented a real dilemma to the industrialized world. On the one hand is the oreanic chemical industry which is a mainstay of modern society. On a worldwide basis, i t gives employment directly to hundreds of thousands of people, and its sales amount to several hundred billion dollars anuuallv. On the other hand is the enormous world appetite for energy for countless endeavors. Of the total annual eas and ~ e t r o l e u mnroduction. less than 10% is required & the chemical industry for all df its raw material and energy conversion needs. Based only on the requirements of this industry, there should be little concern about feedstock futures and the proven reserves could last for a lona- time. perhaps a thousand years or more. Unfortunately, the bank notes are still being stuffed into the stove for heat. Reserves are being consumed a t an alarming rate. Future feedstock availability is therefore of much concern. As supplies dwindle and exploration and production costs mount, feedstock costs will continue to soar. By extrapolation of present trends in the petroleum industries, it is estimated that the world's production of petroleum should peak sometime between 1990 and 1995. At this point, worldwide demand should exceed production and the inevitahle decline of the petroleum age should set i n 4 Even if the emphasis for fuel and feedstocks is returned to the other fossil oreanic reserves stored in coal. shale. and tar sands. the " eventual depletion will still occur a t a reasonably forecastable oeriod in the future. A most eleeant analvsis of the world's initial and remaining recoverable resources of fossil organic raw materials has been made. In this analvsis. the brevitvof the time during which these materials wili beconsumed;assuming that present exploitation practices are continued, is emphatically shown by a graph plotting their use on a time scale from 6004) years in the past to 5000 years in the future4 (see Fig. 1). On this graph, the exhaustion of the fossil reserves is represented by a narrow peak of some 300-400 years (about 3.5% of the 10,000 year period!). If mankind is to maintain an industrial civilization comparable to what has been developed so far, this graph tells us that such a civilization has a limited future unless huge and inexhaustible energy sources are developed. An assessment of future chemical feedstock supplies must bank very heavily on the world's energy picture and must
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Figure 1. Graph showing predicted consumption of recoverable resources of organic raw materials based on present practices.
distinguish between the near-term (1980-2000) and the long-term (beyond 2000). Fortunately, petroleum depletion will not occur catastrophically, so there is a lead-time during which other options can he developed. Near-Term Outlook
In the next 10-20 years, the most important contribution will, undoubtedly, be development of alternate fossil energy sources. This can increase the supply of petroleum to sustain . petrochemical operation and maintain productivity and pay hack for huge capital expenditures already made in petrochemical What must not happen is complete transference of the petroleum appetite to the more abundant hut still finite cod, shale, and heavy oil reserves. These latter need to be exploited but prudence demands and survival may depend on concurrent development of renewable biomass sources for both materials and energy. Aside from the fact that continued combustion of fossil carbon ultimately will lead to exhaustion of the non-renewable resource, an even more impellinr reason for shifting awav from I U V ~ 11urnin:: rc.\sil resrrws i c ~ ~ . I ~ I I I :rtm
