UNIT IX SECTION 7 COAL HAS BECOME A PROLIFIC SOURCE OF "BETTER THINGS FOR BETTER LIVING THROUGH CHEMISTRY" Introduction. There's hardly a thing that a man can name Of use or beauty in life's small game But you can extract in alembic or jar From the "physical basis" of black coal tar— Oil and ointment, and wax and wine, And the lovely colors called aniline; You can make anything from salve to a star, If you only know how, from black coal tar. — Punch, London. In 1919 the United States Senate Finance Committee held hearings on the serious question: Should the United States Government "promote the establishment of the manufacture of coal-tar products in the United States?" Marston Taylor Bogert, Professor of Chemistry at Columbia University, testified before the committee that " a well-developed synthetic dye-stuffs industry is absolutely necessary for the security of our country." Twenty years later, as the result of an intensive program of chemical research, we find the United States one of the leaders in the production of a host of new synthetic dyes, pharmaceuticals, flavors, perfumes, and other products which have caused some people to designate the present as the Chemical Age. cent of our dyes, while in In 1914 we made only 10 per 1940 we produced about 95 per cent of our dyes and exported more than 25,000,000 pounds. Among the outstanding better things for better living which are made from coal through chemistry are the synthetic plastics, discussed in Section 6. The other types of products made from coal will be discussed in this Section. Coal Tar Is the Main Raw Material for Many Synthetic P>roducts. When soft (bituminous) coal is heated in the absence of air to produce coke, tar is one of the by-products. 688 Previous to the World War
"BETTER THINGS" FROM COAL 689 of 1914—1918 much of this tar produced in the United States was thrown away. Germany, to be sure, had learned how to use coal tar, but it required the World War to teach the rest of the world that coal tar is one of the most useful things in the world. When coal tar is fractionally distilled, a number of materials are obtained which form the starting-point for the synthesis of dyes, drugs, perfumes, flavors, high explosives, and photographic developers. Figure 302 shows only a few of the products that may be obtained from benzene, for example, by well-understood chemical reactions. As an example of the ramifications of the coal-tar industry, let consider phenol (carbolic acid). Phenol, an antiseptic itself, may be treated with nitric and sulfuric acids to produce picric acid, which is not only an excellent disinfectant but also a brilliant yellow dye as well as a high explosive. A study of Fig. 302 will show how phenol is converted into such important drugs as aspirin, salicylic acid, phenacetin, and "Salvarsan." us Sjmthetic Perfumes and Flavors Now Replace Natural Products.^ Centuries ago adventurous merchants braved unknown deserts and uncharted seas to search the world for rare perfumes, spices, and drugs because of the high prices they would bring. The chemist has analyzed perfumes and flavoring materials and can consequently duplicate, although still imperfectly, most of the natural products at a much lower cost. At the same time he has produced a large number of perfumes previously unknown. Thus wintergreen flavor can be prepared before your eyes in five minutes by simply heating salicylic acid and methyl alcohol with sulfuric acid. Isoamyl acetate is known to be the principal constituent of pear flavor, while ethyl butyrate is the principal constituent of pineapple flavor. Such essential oils as jasmine, orange blossom, musk, heliotrope, tuberose, and ylang-ylang can now be synthesized from coal-tar compounds. Coumarin, which is used in perfumes having the "new-mown hay" odor and as a substitute for vanilla in cheap extracts, can now be synthesized. Vanillin, the chief flavoring ingredient of vanilla beans, is synthesized today on a large scale. Originally all perfumes were powders, gums, scented oils, or water or wine in which flowers had been steeped. In the tenth century, the Arabian doctor Avicenna first introduced distillation to concentrate ' The average annual increase in flavors and perfumes between 1919 and 1937 was 29 per cent; in photographic chemicals, 22 per cent. Total coal-tar finished products showed an average annual rise of 18 per cent. . . . Compare this with the average annual increase in automobile production of 9.6 per cent.