Chlorination, hydrocarbon cores

Chisso-Asahi uses a spouted bed process for the production of their coated materials (12). A 12,000 t/yr faciHty is located in Japan. The semicontinuous process consists of two batch fluid-bed coaters. A dilute polymer solution is prepared by dissolving 5% polymer and release controlling agent into a chlorinated hydrocarbon solvent such as trichloroethylene. The solution is metered into the spouted bed where it is appHed to the fertilizer core. Hot air, used to fluidize the granules, evaporates the solvent which is recovered and reintroduced into the process. Mineral talc, when used, is either slurried into the polymer solution or introduced into the fluidizing air. 

Sediment pollution. The concentrations of pollutants in the dated sediment cores have been determined in our laboratory by atomic absorption spectrophotometry (AAS). Donazzolo et al. (15) and Pavoni et al. (16) reported mainly heavy metal concentrations. Marcomini et al. (17) and Pavoni et al. (18) discussed the concentration profiles of organic pollutants such as chlorinated hydrocarbons and polycyclic aromatic hydrocarbons. 

With the objective of oxidizing the fullerene core, radiolysis of any chlorinated hydrocarbon solvent provides the means of forming strongly oxidizing radical species [71]. For example, the radiation-induced ionization of dichloroethane (DCE) yields the short-lived and highly reactive solvent radical cation. In general, the electron affinity of [DCE] + is sufficient to initiate one-electron oxidation of the fullerene moiety (Eq. 6) [72-76]. 

Venkatesan MI, de Leon RP, van Geen A, Luoma SN (1999) Chlorinated hydrocarbon pesticides and polychlorinated biphenyls in sediment cores from San Francisco Bay. Marine Chem 64, 85-97. 

The foams, marketed by Rohm as Rohacell, are stable at room temperature to hydrocarbons, ketones, chlorinated solvents and 10% sulphuric acid. They may be used under load at temperature up to 160°C. Uses quoted for these materials include bus engine covers, aircraft landing gear doors, radar domes, domes, ski cores and tennis racket cores. Their potential is in applications demanding a level of heat deformation resistance, solvent resistance and stiffness not exhibited by more well-known cellular polymers such as expanded polystyrene and the polyurethane foams. 

Hydrocarbons. In other publications the historical trend of organic pollutant concentrations, namely polychlorinated biphenys (PCBs), chlorinated pesticides DDT and metabolites DDE, DDD, and polycyclic aromatic hydrocarbons (PAHs), have been reconstructed. For this purpose the sediments of the core sampled in the Lagoon area close to the industrial district were employed (16,17). 

Any increase of polarity of the hydrocarbon, for example by substitution with chlorine or by replacing CH2 groups by ether oxygens, also increases incompatibility with perfluoroalkanes as polar interactions become more important [89, 96]. Polar groups are fundamental constituents of the mesogenic cores, especially as linking units and as substituents at aromatic moieties, and these groups increase the incompatibility between the aromatic cores and Rp-chains. 

The gas-phase chemistry reviewed in this chapter shows how the pattern of substitution of chlorine and fluorine atoms on the parent hydrocarbon affects its atmospheric degradation. Although numerous reaction details need to be investigated and some discrepancies resolved, a core of reliable data is available from which one can deduce which HFC or HCFC may have deleterious atmospheric consequences and which potential substitute appears environmentally acceptable. However, the work is not finished. This work has dealt only with the gas-phase chemistry. Research is still needed into the heterogeneous chemistry of HFC and HCFC degradation products and into the biological effects that they may have. It is then up to the atmospheric modelers to combine this scientific information with emission scenarios and meterology to ascertain the feasibility of a particular CFC substitute. 

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