Two routes to 1,2-cyclohexanediol catalyzed by zeolites under solvent-free condition
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Two routes to 1,2-cyclohexanediol were studied. Specifically: (a) the hydrolysis of cyclohexene oxide and (b) the direct dihydroxylation of cyclohexene with aqueous hydrogen peroxide. Both reactions were carried out with zeolites as catalysts under solvent-free conditions, aiming to establish green routes for the synthesis of 1,2-cyclohexanediol. In the first route, H-Beta and H-ZSM-5 zeolites were used as catalysts, respectively. According to the results, H-ZSM-5 was a suitable catalyst for the hydrolysis of cyclohexene oxide. A 88.6 % yield of 1,2-cyclohexanediol could be obtained at a 96.2 % conversion of cyclohexene oxide under mild conditions, and the catalyst could be reused for three times. Compared with H-ZSM-5, H-Beta gave a much lower selectivity (63 %), although it was more active. In the second route, Ti-Beta zeolites with three different Ti loadings prepared via a simple two-step strategy were characterized and used. The results indicated that it was the framework Ti species which was responsible for the catalytic activity. The resultant Ti-Beta-3 % could give a 90.2 % cyclohexene conversion at a 66.2 % selectivity of 1,2-cyclohexanediol.
Keywords1, 2-Cyclohexanediol Hydrolysis Dihydroxylation Zeolites Solvent-free
- 9.H.Y. Tian, Y.D. Zhang, Z.X. Wang, Spec. Petrochem. 26, 37 (2009)Google Scholar