Catalytic hydrodechlorination of 1,1-dichlorotetrafluoroethane by Pd/Al{sub 2}O{sub 3}
- Univ. of Pittsburgh, PA (United States)
Palladium supported on {gamma}-alumina displays high activity for the hydrodechlorination of 1,1-dichlorotetrafluoroethane. High H{sub 2} partial pressures are needed to avoid deactivation, and steady state is obtained after {approximately}5 h time on stream. Under these conditions (H{sub 2}/CFC feed ratio = 20) the reaction is zero order in H{sub 2} partial pressure and positive (0.65) order in 1,1-dichlorotetrafluoroethane partial pressure. 1-chloro-1,2,2,2-tetrafluoroethane, and 1,1,1-trifluoroethane, with approximately 85% selectivity toward the desired CF{sub 3}CFH{sub 2}. The apparent activation energies associated with the formation of each product range from 52 to 68 kJ/mol. All three major products have a nonzero rate of formation in the limit of zero conversion, the implication of which is that all are primary products. The kinetics results are consistent with a reaction mechanism involving a carbene intermediate. Variation of the temperature at which the catalyst is prereduced from 300 to 600 C results in an increase in particle size from 11-53 nm and in an increase in the hydrodechlorination TOF from 2.3 to 5.0 s{sup {minus}1} 25 refs., 8 figs., 4 tabs.
- OSTI ID:
- 468689
- Journal Information:
- Journal of Catalysis, Journal Name: Journal of Catalysis Journal Issue: 2 Vol. 164; ISSN 0021-9517; ISSN JCTLA5
- Country of Publication:
- United States
- Language:
- English
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