Preparation Of Heteropoly Acid Composites And Catalytic Synthesis Of 2-(1-Cyclohexenyl) Cyclohexanone

In this work, we studied preparation of 12-tungstophosphoric acid composites, and then composites were employed as catalysts to synthesize 2-(1-cyclohexenyl)cyclohexanone in this paper. A series of 12-tungstophosphoric acid composites were prepared by two typical methods, namely reflux adsorption method and impregnation method. The composites were characterized by XRD,TG-DTA, IR etc. The optimum reaction conditions and longevity of catalysts were investigate.First of all, active carbons were selected as supports to prepare 12-tungstophosphoric acid composites (PW12/C) by reflux adsorption method. The results of TG-DTA and other different analysis indicated that 12-tungstophosphoric acids decomposed gradually through analysis of samples calcined composites under the different temperatures. From the infrared spectrometry, we known the Keggin structure of 12-tungstophosphoric acid decomposed at the 600℃. The PW₁₂/C were used as catalysts for the synthesis of 2-(1-cyclohexenyl)cyclohexanone. The optimum reaction conditions were as follows:amount of 12-tungstophosphoric acid supported on active carbon 25%, amount of the catalyst used in the reactants 3.0%, reaction time 2.5h, reaction temperature 150℃.Secondly, The molecular sieve SBA-15 has more good characters, such as higher specific surface, uniform porous channels. It is regarded as an excellent support. The molecular sieve SBA-15 itself does not has acidity. In this paper 12-tungstophosphoric acids were introduced in the mesoporous molecular sieve by impregnation method. The 12-tungstophosphoric acids also highly dispersed in the molecular sieve and kept Keggin structure. In the composites there are strong mutual interaction between the support SBA-15 and 12-tungstophosphoric acid, the hydrothermal stability of support and acid all dropped.Finally, Phosphotungstic acid and phosphomolybdic acid were mixed in 1:1 proportion, The Catalytic activity was good when it was supported by Impregnation method, During the synthesis of 2-(1-cyclohexenyl)cyclohexanone, Conversion of cyclohexanone could reach 86.5%,The catalyst had favorable Industrial prospect.