Indirect Hydration Of Cyclohexene For The Synthesis Of Cyclohexanol

Cyclohexanol is an important basic chemical material,mainly used in the production of adipic acid,hexanediamine,cyclohexanone,caprolactam,etc.Currently,there are three main methods for synthesizing cyclohexanol: phenol hydrogenation,cyclohexane oxidation,and cyclohexene hydration.Among them,cyclohexene hydration has the advantages of low energy consumption and high safety performance,and is currently the most widely used method for preparing cyclohexanol.The cyclohexene hydration method is divided into the direct hydration and the indirect hydration,the indirect hydration process route for the production of cyclohexanol was carried out involving the initial esterification reaction of cyclohexene with carboxylic acid and the hydrolysis of ester,two steps,in which the indirect hydration process performances high conversion of cyclohexene and yield of cyclohexanol in stark contrast to the direct hydration.Highly active catalysts are essential for both the esterification of cyclohexene with carboxylic acid and ester hydrolysis.In this thesis,a silica-sulfonic acid catalyst was synthesized and its catalytic performance was investigated in the preparation of cyclohexanol by indirect hydration of cyclohexene.The main contents of this thesis include the following two parts:(1)A silica-sulfonic acid catalyst was prepared and characterized,followed by an investigation into its catalytic performance in the preparation of cyclohexanol by indirect hydration of cyclohexene via cyclohexyl formate.The results showed that 98.0%conversion of cyclohexene and 98.0% selectivity of cyclohexyl formate were obtained during esterification under optimal conditions.During hydrolysis,the conversion rate of cyclohexene was 90.5% and the selectivity toward cyclohexanol was 99.8%.(2)The catalyst’s performance was investigated for the production of cyclohexanol via indirect hydration of cyclohexene with cyclohexyl acetate.A 57.5% conversion rate of cyclohexene and 96.7% selectivity of cyclohexyl acetate were achieved,which were lightly less than the esterification of cyclohexene with formic acid.The conversion of cyclohexene was 80.4% and the selectivity of cyclohexanol was 92.9% during hydrolysis.