Date of Award
Master of Science in Chemical Engineering - (M.S.)
Chemical Engineering, Chemistry and Environmental Science
Joseph W. Bozzelli
The primary objective of this study was to evaluate the viability for conversion of chlorocarbon wastes solvents into useful hydrocarbons and HCl by catalytic reduction. The second objective was to investigate the pathways for these hydrodechlorination reactions over the chosen alumina supported Palladium and nickel catalysts as well as determine selectivities, product distribution, and deactivation mechanism.
Reactions of trichloroethylene with hydrogen over alumina supported palladium catalyst was studied in temperature range 40°C to 57°C at one atmosphere total pressure. The major products observed were ethane and (cis) 1,2 dichloroethylene with trace products chloroethylene, chloroethane and (trans) 1,2 dichloroethylene. At the increased temperature, increased conversion to useful hydrocarbon ethane with decrease in conversion to lower chlorine content hydrocarbons was observed. The activity of catalyst decreased 40 % after one hour of reaction. The activation energy was found to be 12.1 kcal/mole for hydrodechlorination of trichloroethylene.
Hydrodechlorination of 1,1,1 trichloroethane with hydrogen over alumina supported palladium catalyst was studied in temperature range of 57°C to 77°C at one atmosphere total pressure. A free radical mechanism involving formation of three intermediate and concerted addition of hydrogen to the intermediate was proposed as the mechanism for the formation of ethane as a terminal product. The activation energy was found to be 12.75 kcal/mole for reactions of 1,1,1 trichloroethane with hydrogen.
Hydrodechlorination of trichloroethylene with hydrogen over nickel catalyst was studied in the temperature range of 165 to 189°C at one atmosphere total pressure. Higher conversion (95 %) to low molecular weight hydrocarbons methane, ethylene, ethane and propyne was observed along with traces of chloroethane. In the temperature range studied, selectivity is 65 % to ethane and at higher temperatures, increased conversion to methane was observed. The activation energy was found to be 7 kcal/mole for hydrodechlorination over nickel catalysts.
Shah, Atul R., "Hydrodechlorination reactions of trichloroethylene and 1,1 1, trichloroethane over alumina supported palladium catalysts, and, trichloroethylene over nickel catalyst" (1988). Theses. 2008.