Coal-tar derivatives

Qumones are colored p benzoqumone for example is yellow Many occur natu rally and have been used as dyes Alizarin is a red pigment extracted from the roots of the madder plant Its preparation from anthracene a coal tar derivative m 1868 was a significant step m the development of the synthetic dyestuff industry... 

Saccharin was discovered at Johns Hopkins Uni versity in 1879 in the course of research on coal tar derivatives and is the oldest artificial sweetener In spite of Its name which comes from the Latin word for sugar saccharin bears no structural relationship to any sugar Nor is saccharin itself very soluble in wa ter The proton bonded to nitrogen however is fairly acidic and saccharin is normally marketed as its water soluble sodium or calcium salt Its earliest applications were not in weight control but as a... 

Many valuable chemicals can be recovered from the volatile fractions produced in coke ovens. Eor many years coal tar was the primary source for chemicals such as naphthalene [91-20-3] anthracene [120-12-7] and other aromatic and heterocycHc hydrocarbons. The routes to production of important coal-tar derivatives are shown in Eigure 1. Much of the production of these chemicals, especially tar bases such as the pyridines and picolines, is based on synthesis from petroleum feedstocks. Nevertheless, a number of important materials continue to be derived from coal tar. 

Triaryl phosphates are produced from the corresponding phenols (usually mixtures) by reaction with phosphoms oxychloride, usually in the presence of a catalyst (94—96). They are subsequently distilled and usually washed with aqueous bases to the desired level of purity. Tricresyl phosphate was originally made from petroleum-derived or coal-tar-derived cresyflc acids, ie, cresols, variously admixed with phenol and xylenols. Discovery of the toxicity of the ortho-cresyl isomers led manufacturers to select cresols having very Httle ortho-isomer. 

One of the research projects that von Hoffman suggested to his students was an investigation of the possibility of producing quinine from coal tar. Quinine is a valuable drug for the treatment of malaria. Perkin decided to take on this task and tried to convert both allyl toluidine and aniline (coal tar derivatives) into quinine. His experiments failed, but he noticed that an ugly black sludge was left behind on the bottom of the reaction flask in the aniline experiment. Curious about the residue, he added ethanol (ethyl alcohol) to the flask. A beautiful, deep purple solution formed when the sludge dissolved in the alcohol. 

The oil furnace process uses aromatic petroleum oils and residues as feedstock and in the oil furnace process (Fig. 1), a highly aromatic feedstock oil (usually a refinery catalytic cracker residue or coal tar-derived material) is converted to the desired grade of carbon black by partial combustion and pyrolysis at 1400 to 1650°C in a refractory (mainly alumina) -lined steel reactor. 

Polynuclear aromatic hydrocarbons (PAH s) are produced in most incomplete combustion processes. Examples are internal combustion engines, effluents from coal fired electricity generating plants, tobacco smoke, and from coking operations in steel and aluminum refineries, PAH s are also present in coal tar derived and coal tar containing products such as creosote and roofing pitch. They are found in the water we drink and the air we breathe, and are a ubiquitous component of our environment. 

The formation of gas was low. From the carbon balance, only 3% of the total carbon formed gaseous products. The hydrogen consumption was approximately 3100 scf/bbl, of which nearly 80% was consumed in liquid hydrogenation. This preliminary result demonstrated that the flash pyrolysis coal tar derived from a subbituminous coal is amenable to hydrorefining. 

Ivan Levinstein, Observations and Suggestions on the Present Position of the British Chemical Industries, with Special Reference to Coal-Tar Derivatives, J. Soc. Chem. Ind. 5, 351-359 and 414 (1886). 

The import of benzene into the United States is dependent on domestic production and demand. Imports of benzene (both petroleum and coal tar derived) into the United States were approximately 200 million L (387 million pounds) in 1990, 305 million L (591 million pounds) in 1991, 272 million L (528 million pounds) in 1992, 376 million L (729 million pounds) in 1993, and 304 million L (589 million pounds) in... 

The most common types of damage caused by chemicals in workers is probably to the lungs and to the skin. These are the main sites of the body that are exposed to chemicals. The most common industrial disease is dermatitis, which accounts for more working days lost than all the other industrial diseases together. If solvents or chemicals that workers handle come into contact with their hands, this can lead to irritation. More serious is contact dermatitis which results from repeated exposure over time. Sometimes serious allergic dermatitis occurs, where the chemical acts to sensitize the skin. Workers in the paper and printing industry are prone to skin diseases, and photographic chemicals, metals, resins, and coal tar derivatives can all sensitize the skin. As we have seen, certain chemicals, such as dioxins, can cause a particularly severe form of acne, chloracne. 

Nearly every girl in this school wears a dress that has many colors upon it. But how many know where those dyes come from. They are coal tar derivatives. 

Shampoos are also formulated with antidandruff agents. Water-insoluble antidandruff agents, such as zinc pyrithione (ZPT), selenium sulfide, climbazole, coal tar derivatives, and sulfur, have been used in many products for treating dandruff. In the last decade there have been many new developments in this kind of product providing improved antidandruff efficacy. Three-in-one shampoos are also available, which provide cleaning, conditioning, and antidandruff benefits in one product. 

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