Manufacturing of chemicals

This example illustrates a subtle control of a chemical reaction by a delicate manipulation of tire stereochemical environment around a metal centre dictated by tire selection of tire ligands. This example hints at tire subtlety of nature s catalysts, tire enzymes, which are also typically stereochemically selective. Chiral catalysis is important in biology and in tire manufacture of chemicals to regulate biological functions, i.e., phannaceuticals. 

D. F. W. Hardie, Electrolytic Manufacture of Chemicals from Salt, The Chlorine Institute, Inc., New York, 1975. 

Other Organic Processes. Solvent extraction has found appHcation in the coal-tar industry for many years, as for example in the recovery of phenols from coal-tar distillates by washing with caustic soda solution. Solvent extraction of fatty and resimic acid from tall oil has been reported (250). Dissociation extraction is used to separate y -cresol fromT -cresol (251) and 2,4-x5lenol from 2,5-x5lenol (252). Solvent extraction can play a role in the direct manufacture of chemicals from coal (253) (see Eeedstocks, coal chemicals). 

Bleaching. The largest single use for hydrogen peroxide in the United States and North America is wood pulp bleaching, but consumption for the manufacture of chemicals, environmental appHcations, and for bleaching cotton (qv), wool (qv), and other textiles (qv) is significant. 

C -Chemisty. A great deal of research has been undertaken on the development of PGM catalysts for the manufacture of chemicals and fuels from syngas, a mixture of CO and H2 obtained from coal gasification (see Coal conversion processes). 

The predominant use of arsenic ia the United States is ia the manufacture of chemicals. During the 1980s, the market for arsenic chemicals had shifted from cotton farming, where its use is now restricted because of environmental considerations, to wood (qv) preservatives for the protection of lumber and other wood products. Arsenic trioxide is the basic commodity of commerce from which a number of important chemicals are manufactured. 

Meta-phenylenediamine, a crystalline solid with a melting point of about 60°C, gives cured resins with a heat distortion temperature of 150°C and very good chemical resistance. It has a pot life of six hours for a 200 g batch at room temperature whilst complete cures require cure times of four to six hours at 150°C. About 14 pts phr are used with the liquid epoxies. The main disadvantages are the need to heat the components in order to mix them, the irritating nature of the amine and persistent yellow staining that can occur on skin and clothing. The hardener finds use in the manufacture of chemical-resistant laminates. 

Laminates have been prepared for the manufacture of chemical plant. They have better heat and chemical resistance than the polyester- epoxide- phenolic- or aminoplastic-based laminates but because of the low viscosity of the resins were not easy to handle. Because they were also somewhat brittle, furan-based laminates have been limited in their applications. 

There is a wide range of conversion levels. The term maximum conversion type has no precise definition but is often used to describe a level of conversion, where there is no net fuel oil manufactured. A fuel products refinery with specialities may manufacture lubricating oils, asphalts, greases, solvents, waxes and chemical feed stocks in addition to the primary fuel products. The number and diversity of products will naturally vary from one refinery to another. Refineries produce chemical feed stocks for sale to the chemical affiliates and do not have responsibility for the manufacture of chemical products directly. Both operations may be carried out at the same physical location but the corporate product responsibilities are usually separate. 

Refineries produce chemical feed stocks for sale to the chemical affiliates and do not have responsibility for the manufacture of chemical products directly. Both operations may be carried out at the same physical location but the corporate product responsibilities are usually separate. 

Crystallization continues to be the most widely used method of separating or resolving enantiomers (optical resolutions). The manufacture of chemicals and pharmaceuticals as purified optical isomers, or enantiomers, has taken on a pivotal importance in the pharmaceutical, agricultural and fine chemicals industries over the past 15-20 years. Crystallization has been and continues to be the most widely used method of separating or resolving enantiomers (optical resolutions), and is particularly well suited to separations at large scale in manufacturing processes (Jacques etal., 1981 Roth etai, 1988 Wood, 1997 Cains, 1999). 

Vessels in which steam is generated by the use of heat resulting from operation of a processing system containing a number of pressure vessels such as used in the manufacturer of chemical and petrochemical products [1]... 

The history of the development of a wide range of catalytic processes illustrates the generality of the points we have made in the previous sections to such an extent that we can sum up with a set of precepts for the improvement of routes to, and of processes for, the manufacture of chemical products. 

Selection of polymers used in the manufacture of chemical protective clothing (CPC) is a complex task. It involves evaluating breakthrough times and permeation rates in conjunction with such task requirements as tactility and resistance to cuts and abrasion. But, it involves a more basic problem — that of deciding which polymer(s), in the absence of test data, might be most likely to resist permeation by a specific chemical. These decisions are faced not only by users of CPC (e.g., industrial hygienists), but also by poljnner chemists and CPC manufacturers. 

Local ones are listed in the yellow pages of the telephone directory. The laboratory operator should contact more than one for suggestions and estimates. In such discussions, a disposal service vdll ask detailed questions as to the exact nature of the waste and quantities involved. An agreement will be made about the types of shipping containers to be used. These are non-returnable. The disposal service may sell suitable containers and require these for certain types of waste. In other cases, the laboratory may provide its own. If drums are needed, they are available from companies engaged in drum reconditioning. Manufacturers of chemicals may have used drums available at reasonable prices, but since these wdll contain residues of their former contents, a check for compatibility must be made before using them. 

There is no continuity in sizing of chemical equipment. There are discrete changes in capacities of chemical equipment of all kinds, either due to state and international standards or due to internal standards of individual manufacturers of chemical equipment. For instance, according to DIN standards, the volumes of glass-lined reactors increase in... 

Most of the materials used in the manufacture of chemicals are poisonous, to some extent. The potential hazard will depend on the inherent toxicity of the material and the frequency and duration of any exposure. It is usual to distinguish between the short-term effects (acute) and the long-term effects (chronic). A highly toxic material that causes immediate injury, such as phosgene or chlorine, would be classified as a safety hazard. Whereas a material whose effect was only apparent after long exposure at low concentrations, for instance, carcinogenic materials, such as vinyl chloride, would be classified as industrial... 

When considering the design of processes for the manufacture of chemical products, the market into which they are being sold fundamentally influences the objectives and priorities in the design. Chemical products can be divided into three broad classes ... 

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