It has been found that the hydrogenation rate of diene hydrocarbons depends on the adsorption coefficient of diene on palladium alloy membrane catalyst. The composition of the reaction products proved to be different during hydrogen introduction through the membrane catalyst and during the supply of hydrogen-hydrocarbon mixture. The reaction rate increased as a result of hydrogen transfer through the membrane catalyst especially in the case of liquid-phase hydrogenation of different organic substances. The withdrawal through the membrane catalyst of hydrogen formed in the process of dehydrogenation improved the yield of this reaction products. The selectivity of hydrogenation and dehydrogenation on palladium membrane catalysts was higher than on other heterogeneous catalysts. The coupling of hydrogenation and dehydrogenation on the membrane catalyst increased the reaction rate and selectivity. The conditions of the reactions coupling by hydrogen transfer through the membrane catalyst have been found as a result of mathematical simulation. © 1981, Elsevier Science & Technology. All rights reserved.