SOLID CATALYST TREATED WITH ANION .19. SYNTHESIS OF THE SOLID SUPERACID CATALYST OF TIN OXIDE TREATED WITH SULFATE ION

A solid superacid catalyst with an acid strength of Ho ≤ -16.04 was synthesized from tin hydroxide, which was obtained from the solution of pH 10, by exposing to 3 M H2SO4 followed by calcination in air at 823 K; the catalyst, SO2-4/SnO2, was active for the skeletal isomerization of butane to isobutane at room temperature. The specific surface area of SO2-4/SnO2 was much larger than that of SnO2 without the sulfate treatment; by X-ray diffraction (XRD) analysis the degree of crystallization of the former material was much lower than that of the latter. Infrared (IR) spectra showed the catalyst to possess a bidentate sulfate ion coordinated to the metal. The present superacid showed the catalytic action of oxidation at elevated temperatures of >450 K; acetaldehyde and acetone were obtained as products from the hydration of ethene, and high selectivity of >95% for the formation of cyclohexanone from cyclohexanol was observed in the presence of water. © 1990.