<text><span class="style10">hemicals and Biotechnology (1 of 3)</span><span class="style7">The chemical industry turns readily available raw materials into thousands of useful products. Principally from coal, oil, natural gas, air, water, limestone, salt and sulfur, the industry manufactures drugs, fertilizers and pesticides, soap and detergents, cosmetics, plastics, acids and alkalis, dyes, solvents, paints, explosives and gases.Biotechnology also produces useful products, but by biological rather than chemical methods. Living organisms - or substances produced from them - are used to make drugs, to improve crops, to brew alcohols, and even to extract minerals. Some of its methods, such as fermentation, are ancient, while others are so new that they are barely out of the research laboratory.</span><span class="style10">The birth of the chemical industry</span><span class="style7">The first chemical to be produced on a large scale was </span><span class="style19">soda</span><span class="style7"> (sodium carbonate), which was needed primarily in glass and soap manufacture. In 1787 the French chemist Nicolas Leblanc (?1742-1806) devised a method of mixing common salt (sodium chloride) with sulfuric acid to produce sodium sulfate, which was then mixed with coal and limestone and roasted. The resultant 'black ash' was dissolved in water and then evaporated to extract the soda. Subsequently the Leblanc process was replaced by a process using salt, carbon dioxide and ammonia. Soda is typical of most products manufactured by the chemical industry in that it requires further processing to make useful products.Other important landmarks in the growth of the chemical industry were the production of bleaching powder (a bleaching agent and disinfectant) in 1799, and the invention of synthetic dyes, beginning with Perkin's mauve in 1856. The production of artificial fertilizers, which supply plants with nitrogen, potassium and phosphorus, was also significant. The first of these was </span><span class="style19">superphosphate</span><span class="style7">, manufactured from 1834 onwards by mixing phosphates with sulfuric acid. The use of electrolysis to extract valuable chemicals by passing electrical currents through salt solutions began in 1894 with the Castner-Kellner process for making pure caustic soda.</span></text>
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<text><span class="style10">nlike other manufacturing industries,</span><span class="style7"> where several raw materials are typically required to make a single product, the chemical industry derives thousands of useful products from a smaller number of raw materials.For example, ethylene - a product of the refinement of crude oil - is used to form a few major chemicals, which in turn spawn hundreds of derivative products.</span></text>
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<text>ΓÇó CHEMISTRYΓÇó MEDICAL TECHNOLOGYΓÇó THREATS TO THE ENVIRONMENTΓÇó OIL AND GASΓÇó RUBBER AND PLASTICSΓÇó TEXTILES</text>
