ADSORPTION OF ACETYLENE AND WATER ON ZEOLITES RESULTING IN HYDRATION TO ACETALDEHYDE

Adsorption of water and acetylene on Cd forms of LTA, X-, and Y,FAU, E RI, CHA, PHI, MOR, MFI, and clinoptilolite active in the catalytic hyd ration of acetylene at 453 K and the adsorption of acetylene on inacti ve H, Na, Co, and La forms of Y,FAU were studied with i.r. spectroscop y at 298 K. Acetylene (1) adsorbs on acidic OH groups; (2) is weakly b ound to cations (nu(C=C) = 1,958 cm(-1)); (3) forms cadmium acetylide (nu(C=C) = 1,947 cm(-1)); and (4) is linked in side-on configuration t o Cd2+ (nu(C=C) = 1,930 cm(-1)). Water dissociated heterolytically was found to react with adsorbed acetylene. Formation of adsorbed acetald ehyde was observed on Cd zeolite catalysts as well as on catalytically inactive forms of faujasite but not on H-F,FAU. (C) Elsevier Science Inc. 1996