THERMAL CHLORINOLYSIS OF 1,1-DICHLOROETHANE - CO-PRODUCTION OF 1,1,1-TRICHLOROETHANE AND VINYLIDENE-CHLORIDE

Thermal chlorinolysis of 1, l-dichloroethane (ED) was carried out by means of the labboratory ancl pilot plant scale experiments. 1,1, l-Trichloroethane (MC) and vinylidene chloride (VD) could be co-produced in fairly broad formation ratios by controlling the reaction conditions. Furthermore, if the chlorinolysis was conducted by feeding ED with MC, VD was formed in high yield. On the other hand, MC was also produced in high selectivity by recycling VD with VC to the hydrochlorination section. That is to say, MC and VD could be produced with an optional ratio by combining thermal chlorinolysis with liquid phase hydrochlorination. The results obtained from the laboratory experiments are summarized as follows. (1) While the conversion of ED increased with increasing the molar ratio (C12/ED), the selectivity into MC and VD decreased. (2) The yield of MC and VD (MD Yield) had a maximum at 0.9 of the molar ratio. (3) The product composition could not be affected with the feed rates of ED and chlorine. (4) The split ratio [100×VD/(MC-HVD)] was changed in broad range with the reaction temperature. In case of pilot plant experiments, the thermal chlorinolysis of ED proceeded adiabatically according to the balance of exothermic chlorination with endothermic dehydrochlorination. Consequently, the reaction temperature was uncontrollable and was maintained at 460~480°C throughout the reaction. The chlorinolysis of ED with the tubular reactor gave higher MD yield than the vessel reactor. The split ratio showed the reverse relation. These results are explained on the basis of piston flow for the tubular reactor and perfect mixing for the vessel reactor. The MD yield was increased with increase of the molar ratio and was decreased by increasing the reaction pressure. On the contary, the split ratio was increased with increase of the reaction pressure. It seemed to be reasonable that ED was more favorably converted into dichloroethylenes such as VD than trichloroethanes by reacting ED with chlorine radicals generated more under higher reaction pressure. © 1990, The Chemical Society of Japan. All rights reserved.