Chemical synthetically important organic

The chemistry of the three most important chemical classes of organic colorants, the azo, carbonyl and phthalocyanine classes, has been dealt with individually in Chapters 3-5 respectively. In this chapter, the chemistry of a further five chemical classes which are of some importance for specific applications is discussed. These classes are the polymethines, arylcarbonium ion colorants, dioxazines, sulfur dyes and nitro dyes. A section of this chapter is devoted to each of these, each individual section contains a description of the principal structural features which characterise the particular colorant type, together with an outline of the chemistry of the main synthetic routes. There are many other chemical types of dyes and pigments that do not fall into the categories previously mentioned, but which are neglected in this text either because they are commercially of little importance or because they have been less extensively investigated. 

A number of years ago. coal tar was the primary, if not the sole, source lor hundreds of important organic chemicals and derivatives, notably the phenols, cresols, naphthalene, and anthracene, as well as other important coal lar end-prralucls, such as solvent naphtha and pitch. In recent years, synthetic processes Tor the production of phenol, the cresols and later the xylcnols. have been developed and thus, to a large extent, have pushed coal lar into the background as a source of feedstocks for (he chemical industry. 

The margins are partly supported by a sustainable share of imports, allowing for import parity pricing. In 2003, approximately 21 percent of China s total chemicals consumption was covered by net imports, mainly commodities. For example, at least half of the consumption of synthetic rubber (69%), plastics (55%), and organic chemicals (50%) was met by net imports. Even at production growth forecasts of 9.6 percent p.a., Chinese capacity levels will not meet demand in the foreseeable future and the country is expected to remain a chemicals net importer beyond 2020. 

C-l Chemistry (Syn Gas). Many important organic chemicals can be produced from the CO and H2 mixture known as syn gas. They range from simple molecules, such as methanol, to high-grade synthetic crude oil. 

Organic derivatives of silicon compounds particularly those involving Si-O-C and Si-N( )-C bonds are of great synthetic importance as intermediates which, when suitably reacted (usually via solvolysis), lead to the desired organic fine chemicals [ 146a]. These classes of compounds may be effectively synthe-... 

Catal5i ic reactions are commonly used in environmental technologies with applications ranging from pollution abatement to pollution prevention. Examples include complex hiocatalytic pathways embedded into natural microbial communities for the bioremediation of toxic compounds into harmless end products, and new and cleaner catalytic synthetic routes for the production of bulk and fine chemicals [1]. The Organization for Economic Cooperation and Development (OECD) has recognized enzyme technology as an important component of sustainable industrial development [2,3]. 

As in the case of pure p-cresol, a number of important organic chemicals are now S3mthesized from m-cresol. For instance, synthetic pyrethroids from m-phenoxy benzalde-hyde obtained from m-cresol are already produced by Sumitomo Chemical Co. of Japan. Similarly 2,3,6-trimethyl phenol (TMP), a vital raw material for manufacture of synthetic Vitamin-E, the fastest growing vitamin, is now made from m-cresol by a number of companies. Slowly, but steadily, m-cresol network is expanding. 

Tariff Commission, Synthetic Organic Chemicals—U. S. Production and Sales, annual, 1917 to date (except 1931-1932). Production, sales, and unit values of dyes, lakes, and toners, medicinal chemicals, flavor and perfume chemicals, plastics and resins, elastomers, rubber-processing chemicals, plasticizers, surface active agents, pesticides, and many individual organic chemicals. Lists producers of all commercially important organic chemicals. Formerly Dyes and Other Synthetic Organic Chemicals (1917-1937). 

Coal tar contains an estimated 10,000 compounds, many of which are important organic chemicals. The use of coal tar as a source of these compounds has been largely relegated to a position below numerous synthetic processes, primarily based on petroleum. Fractionation of coal tar yields the following (approximate temperatures and yields given) ... 

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