Abstract: Disclosed is a catalytic reaction process in which a substance in a liquid reaction system is catalytically reacted with a gaseous substance which is hardly soluble in the liquid reaction system in the presence of a solid catalyst of a non-electroconductive, hydrophobic polymeric material, a part of the surface of which is non-compatible with the liquid reaction system or with the liquid reaction system and a product formed by the catalytic reaction.According to this process, mild reaction conditions can be selected and adopted and separation or recovery of the catalyst can be remarkably facilitated. This catalytic reaction process can be applied to various liquid-gas reactions and can be applied especially advantageously to oxidation and reduction of organic substances and inorganic ions for disposal of waste waters and recovery of valuable substances.