HYDROGEN-DEUTERIUM EQUILIBRATION REACTION OVER PLATINUM SUPPORTED ON POLYAMIDE-6

Catalysis by platinum supported on polyamide-6 was examined for the H//2-D//2 equilibration reaction at 0 degree C in the pressure range of 5-20 Torr (1 Torr equals 133. 3 Pa). Three kinds of polyamides with different molecular weights were prepared as support; the concentration of platinum varied from 0. 5 to 2. 7 wt%. With preadsorption of hydrogen at 0 degree C, the rate of the reaction was found to increase up to 10 times as high as the original level. The rate k//m (HD molecule s** minus **1Pt atom** minus **1) showed a maximum, depending on surface area of the polyamides used, in the range 0. 8-1. 0 wt% of Pt content and its dependence on total pressure is represented by k//m equals K//1P/(1 plus K//2 ROOT P)**2 irrespective of Pt content. No significant isotope effect was observed at 0 degree C. It was found that a linear relationship exists between the enhancement of k//m and the amount of hydrogen preadsorbed, indicating an important role of the preadsorbed hydrogen in activation of the catalysts.