CATALYST FOR REDUCING CARBOXYLIC ACID OR ESTER THEREOF TO ALDEHYDE COMPOUND

摘要

PURPOSE:To easily and inexpensively recover a formed aldehyde compound without generating harmful waste, by using hydrous metal oxide as a catalyst and bringing carboxylic acid or ester thereof into contact with a reducing agent composed of formic acid. CONSTITUTION:A pref. catalyst is hydrous zirconium oxide or hydrous tin oxide and this hydrous metal oxide is crushed so as to obtain a proper particle size to be used as it is or supported by alumina or activated carbon before use. For example, when carboxylic acid or ester thereof is reduced to a gaseous phase, a reaction tube is packed with the above-mentioned catalyst and a liquid mixture of carboxylic acid or ester thereof and formic acid being a reducing agent is sent into the formed catalyst bed as it is or by the use of inert carrier gas such as nitrogen or helium while the reaction pipe is heated to reducing temp. The reaction product flowing out from the reaction pipe is condensed and water is removed from the condensate while the residue is distilled to isolate an aldehyde compound.