PURPOSE: To obtain an olefin adsorbent adsorbing an extremely large amt. of olefin by supporting palladium chloride and copper chloride on a carrier formed by calcining and stabilizing zirconium hydroxide and/or titanium hydroxide after treatment with sulfuric acid.

CONSTITUTION: Palladium chloride and copper chloride are supported on a carrier formed by calcining and stabilizing zirconium hydroxide and/or titanium hydroxide after treatment with about 0.01-10N sulfuric acid to obtain an olefin adsorbent. Though the adsorption reaction of this adsorbent is a known reaction by which acetaldehyde is produced from ethylene, it is accelerated at ordinary temp. with high performance because sulfuric acid as a hyperstrong acid is present in this adsorbent and ethylene is adsorbed by bonding to H+ on the surface of the sulfuric acid. Since this adsorbent requires the presence of water, unlike the conventional adsorbent this adsorbent does not undergo the deterioration of the olefin adsorbing ability due to the coadsorption of water. Since ZrO2 and/or TiO2 treated with sulfuric acid is used as the carrier, an extremely large amt. of olefin is adsorbed.