Gas Phase Hydrogen Spillover and Oxygen Content

A specially constructed all-glass reaction system was used to reinvestigate hydrogen spillover through the gas phase with extremely purified hydrogen, using alkene hydrogenations in the gas phase as test reactions. The spillover reaction could be observed even with hydrogen - with less than 0.01 ppm O2 - which additionally was passed over the same type of Pt/Al2O3 catalyst at the beginning of the line. In a second group of experiments the effect of oxygen traces was investigated, which were added to the hydrogen stream. Small oxygen contents (≤50 ppm) did not influence the reaction, higher contents (≥100 ppm) caused reduced conversion.