Promoter Modifications of Catalytic Activity and Selectivity. Progress Report, April 1, 1982-March 31, 1983

摘要

The influence of alkali promoters on CO hydrogenation was studied as a function of catalyst support (Al sub 2 O sub 3 , SiO sub 2 , SiO sub 2 .Al sub 2 O sub 3 and TiO sub 2 ). Temperature-programmed reaction was used to study the specific rates of CO and carbon hydrogenation, and temperature-programmed desorption studied the change in H sub 2 and CO desorption rates. The role of the support was separately studied for comparison. Specific-activity and product distributions were also studied in a differential reactor with gas-chromatography detection. On all catalysts the selectivity for higher hydrocarbons, particularly olefins, was increased by addition of Na or K promoters. On all catalysts but Ni/SiO sub 2 .Al sub 2 O sub 3 , however, the specific activity decreased; on Ni/SiO sub 2 .Al sub 2 O sub 3 , a slight increase in specific activity was seen. Similarly, significant changes in methanation activation energies were observed for the addition of promoters. Good agreement was obtained between differential reactor studies and temperature-programmed reaction. The role of the promotor is significantly influenced by the oxide support. 12 figures, 4 tables. (ERA citation 08:029288)