SELECTIVE LIQUID-PHASE HYDROGENATION OF ALPHA, BETA-UNSATURATED CARBONYL COMPOUND

摘要

PROBLEM TO BE SOLVED: To carry out the hydrogenation of especially citral to citronellal at a low cost by an economical process having improved space-time yield and reduced investment cost by hydrogenating anα,β-unsaturated carbonyl compound in liquid phase under specific condition. SOLUTION: A compound of formula II is produced by the hydrogenation of anα,β-unsaturated carbonyl compound of formula I (R1 is H or an organic group; R2 to R4 are each H or a 1-4C alkyl) with hydrogen in the presence of powdery palladium and/or rhodium and an organic group while performing the regeneration of the product and the circulation of hydrogen gas in a bubble packed column reactor. The packing material in the bubble column reactor preferably has a hydraulic diameter of 0.5-20 mm and a surface roughness of 0.1 to 10 times the average particle diameter of the powdery catalyst particles at the opening or the channel wall part of the packing material and is made of a metallic material, a plastic material, etc.