ACTIVATION OF PLATINUM-ALUMINA CATALYSTS FOR THE HYDROGENATION OF AROMATIC HYDROCARBONS.

A white spirit fraction was hydrogenated in a continuous flow microreactor unit, using 0. 35% platinum-alumina catalysts. These catalysts contained 0. 0, 0. 40 or 0. 87% chlorine. Chlorination of the catalysts carried out during the process of platinum impregnation was found to enhance significantly their hydrogenation activity. Increasing the reduction temperature from 200 to 500 degree C considerably increased the catalytic activity. The variation in activation energy with the Arrhenius pre-exponential factor, as a function of the catalyst reduction temperature, indicates that catalysts containing 0. 40 and 0. 87% chlorine follow the equation k//o equals exp( minus 3. 25 plus 0. 001E), and hence their surface uniformity would be identical. However, unchlorinated catalysts, both calcinated before reduction or uncalcinated, exhibit considerably different surface uniformity.