Study On GAS Phase Conversion Of Carbon Trtrachloride To Methyl Chloride

Tetrachloride Carbon (CTC) is an ozone depleting substance (ODS). It is mainly used as feedstock of chlorofluorocarbons (CFC), chemical process agent and cleaning solvent. The consumption of CTC should be reduced to 15% of that in 1999 by January 1 2005. However, The CTC output as a byproduct in the production of chloromethane is about 3~5%. In contrast, the feedstock use of CTC in producing non-ODS products is not restricted; hence the development of CTC conversion technology is an urgent subject.Methyl chloride is an important chemical mainly used as raw material to produce organic silicon, silicone polymer, methyl cellulose, pesticides, Pharmaceuticals and some fine chemicals. It can be chlorinated to produce dichloromethane and chloroform which fit the bill with the national economy development demand. Hence, converting CTC to methyl chloride is feasible for its wide spectrum applications and good market prospect.With active carbon supported ZnCl2 catalyst, the reaction was conducted in liquid phase. The results show a low conversion with the maximum yield being lower than 80%. In order to raise the yield of Methyl chloride, it is better to remove the product instantly so as to drive the equilibrium toward the formation of product.With A1C13 catalyst supported on active carbon, such influencing factors as temperature, mole ratio of reactants, residence time and the catalyst content, on the yield of methyl chloride have been investigated experimentally, and the optimum conditions are determined. The results show that the yield and selectivity of methyl chloride can reach 90-95% and 93% respectively under reaction temperature of 200 —300 degree, at theoretical mole ratio of reactants, and residence time of 20-60s. The reactivity of the used catalyst can be recovered basically after a washing with petroleum ether or CTC The feasibility of this conversion reaction has been proved by a pilot scale experiment in a 10 litter tubular reactor.In chapter 3, effects of different catalyst and the catalyst carriers on the conversion of CTC into methyl chloride were studied experimentally. The result shows that the best conversion can be achieved with alumina or aluminum chloride/C catalyst within experiment ranges investigated. The performance of the catalyst and carrier adopted follows the order: alumina/active carbon, aluminum chloride/active carbon, zinc phosphate/active carbon, tin chloride/active carbon, active alumina, zinc chloride/molecular sieve, zinc sulfate/active carbon , iron chloride/active carbon, and zinc chloride/silicon dioxide. By analyzing the...