Industrial Synthesis and Processing

Chemical synthesis is one important aspect of the application of radiation-chemical reactions in industry. Various kinds of radiation-induced syntheses are available, some of which will be described here. There are also nonsynthetic applications including, but not limited to, food irradiation, waste treatment, and sterilization by irradiation. Some of these will be taken up in the next section. 

It is clear from this discussion that the dose requirement and unit cost will be lower if the material has a higher molar mass M and the reaction has a high G value. Thus, the best candidates will be a polymeric material and a chain reaction. Quite often, a free-radical irradiation is used. The radiation source of choice is usually a 60Co - y facility, although electron beam irradiation is also used. Since most radiation-chemical reactions used in industry can also be brought about by other conventional means such as thermal, or photochemical processes, the processing cost must be below 10 t. kg-1 to be competitive, since it is unlikely that the cost of irradiation will come down in future. It should remembered that in figuring the irradiation cost one has to include the cost of operation, maintenance, and the like. (Danno, 1960). 

Various industrial pilot plants and full-scale operations, using radiation-chemical processing have been reported, with production rates -50 to -1000 tons per year (Spinks and Woods, 1990 Chutny and Kucera, 1974). Production rates less than -50 tons per year are not considered viable. These operations are or have been conducted in countries such as the United States, the former U.S.S.R., Japan, and France. However, some operations have also been reported in the former Czechoslovakia and Romania, especially in connection with petroleum industry. In the United States, chlorination of benzene to gammexane (hexachlorocyclohexane) was hotly pursued at one time by radiation or photoinitiation. Since the early seventies the activity has dwindled, presumably due to lack of demand and environmental considerations. 

The numerous radiation-chemical reactions used or proposed for industrial processing include, but are not limited to, the following  

Oxidation of hydrocarbons. Paraffin wax in the petroleum industry was oxidized in a gamma field at a higher temperature to produce higher alcohols and fatty acids. The yield envisaged was as a few thousand tons per year. 

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In this chapter we will consider the following as examples of radiation chemical applications (1) dosimetry, (2) industrial synthesis and processing, (3) irradiation of food, waste, and medical equipment, and (4) low-energy ion interaction with matter. Dosimetry is of fundamental importance for yield calculations and also for personnel exposure. Industrial processing would include... 

Shock-compression science, which has developed and matured since its inception in 1955. has never before been documented in book form. Over this period, shock-compression research has provided numerous major contributions to scientific and industrial technology. As a result, our knowledge of geophysics, planetary physics, and astrophysics has substantially improved, and shock processes have become standard industrial methods in materials synthesis and processing. Characterizations of shock-compressed matter have been broadened and enriched with involvements of the fields of physics, electrical engineering, solid mechanics, metallurgy, geophysics, and materials science... 

In particular, the industry survey revealed a serious weakness in U.S. research efforts involving the synthesis and processing of materials. Moreover, industry has the major responsibility for maintaining the competitiveness of its products and product operations. Collaboration with... 

Transition metal complexes with metal-carbon -bonds are key intermediates in many important industrial processes, in biochemical reactions, organic synthesis, and processes involving aliphatic radicals. Of special interest are those complexes, which are short-lived intermediates in catalytic processes. However due to the high reactivity of the latter complexes, the study of their properties is difficult as their steady state concentration is in most cases far below the detection limit. 

Novel synthesis often unlocks the door to novel materials, phenomena and applications. Materials processing in the laboratory and its transfer to the factory is the key to high quality, high yield, low cost materials. Indeed materials synthesis and processing were identified in the recent National Research Council "Materials Science and Engineering Study"(7) as key to U.S. industrial competitiveness in the 1990 s. 

Interest in the synthesis and processing of mesoporous silica materials has grown extensively since their discovery in 1992, and the exciting potential that these films hold in low-k dielectrics, sensors, nanowire fabrication, catalysis, membrane separations, and many other applications will continue to fuel academic and industrial interest in these films. While there are many new synthesis routes for processing mesoporous silica thin films, spin coating and dip coating remain the most facile methods available. These methods deliver high quality reproducible films that can be used for any of the variety of applications. 

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