超声辅助SiW_(12)/SiO_2催化合成乙酸苄酯及动力学

Ultrasound assisted heteropoly acid catalyst SiW_(12)/SiO_2 for synthesis of benzyl acetate and kinetics

制备负载型硅钨酸(SiW12/SiO2)催化剂,并在超声条件下将催化剂应用于乙酸苄酯的合成中。采用红外光谱仪(IR)和X线衍射仪(XRD)对催化剂进行表征。考察反应温度、催化剂用量、醇酸摩尔比和反应时间对酯化率的影响,并建立了动力学方程。结果表明:所制备的催化剂具有Keggin的结构;在超声频率10 kHz、超声声强1.0 W/cm2的条件下,得到最适宜的反应条件为反应温度110℃、催化剂用量1.5 g、醇酸摩尔比值1.5、反应时间75 min。在最优条件下,酯化率可达95.3%。

Under ultrasonic radiation,the benzyl acetate was synthesized from benzyl alcohol and glacial acetic acid in the presence of SiW12/SiO2 catalyst.The catalyst was characterized by infrared spectrometry（IR） and X-ray diffraction（XRD）.Effects of reaction temperature,the amount of catalyst,molar ratio of benzyl alcohol to glacial acetic acid,and reaction time on the esterification yield were discussed,and the kinetics of benzyl acetate was investigated.Results showed that heteropolyacid retained the Keggin-type structure.The optimum conditions for the reaction were as follows： reaction temperature of 110 ℃,amount of catalyst of 1.5 g,molar ratio of benzyl alcohol to glacial acetic acid of 1.5,and the reaction time of 75 min at 10 kHz ultrasound frequency with 1.0 W/cm2 of supplied ultrasound intensity.Under the conditions,the esterification yield of the reaction reached 95.3%.