Unpromoted and K2O-Promoted Cobalt Molybdate as Catalysts for the Decomposition of Acetic Acid

Summary.  Unpromoted cobalt molybdate was prepared from Co(NO₃)₂·6H₂O and (NH₄)₆Mo₇O₂₄·4H₂O, then calcined between 350 and 600°C for 5 h. K₂O (10 w%), as a promoter, was added to the calcined sample at 350°C from two different sources (i.e. KOH and KNO₃) and was subjected to further calcination at 350°C for 5 h. The catalytic activity of unpromoted catalysts towards the vapour phase decomposition of CH₃COOH was greatly influenced by the increase in the calcination temperature. This is attributed to the diminution of both S _BET and their dual acidic–basic characters. The promoted sample from the KOH source was found to be the most active of the catalysts studied. This is due to its high population of both acidic–basic surface sites and the formation of two new phases. XRD and FTIR analyses of the used catalysts, after the decomposition reaction of acetic acid, showed a remarkable change in its structure compared with the parent samples. E-mail: shalawy99@yahoo.com Received May 8, 2002; accepted (revised) July 9, 2002