Fe_2O_3-ZnO/SiO_2催化氧化异戊醇一步合成异戊酸异戊酯

Catalytic Oxidation of Isoamyl Alcohol to Isoamyl Isovalerate Directly on Fe_2O_3-ZnO/SiO_2

采用浸渍法制备了系列不同Fe2O3、ZnO负载量的Fe2O3-ZnO/SiO2催化剂,并用XRD、BET、SEM等对催化剂进行了表征;考察了以分子氧为氧化剂时,该系列催化剂对异戊醇一步合成异戊酸异戊酯的催化性能,并初步探讨了其反应机理。结果表明,在Fe2O3/SiO2催化剂上引入适量ZnO后,提高了Fe2O3在SiO2上的分散度,减小了Fe2O3的粒径,所制得的Fe2O3-ZnO/SiO2催化剂有较大的比表面积、孔体积、孔径,催化性能优于Fe2O3/SiO2。其中,在Fe2O3与ZnO的协同作用下,6%Fe2O3-4%ZnO/SiO2催化性能最佳,常压下当催化剂用量为0.9 g(占反应物质量的3.5%),反应温度120℃,反应时间9 h,异戊醇一步合成异戊酸异戊酯的选择性达54.5%,收率达31.4%。对该合成机理的初步探讨表明,只有催化剂与分子氧的共同作用下,异戊醇才能高效的合成异戊酸异戊酯。

A series of FeEO3-ZnO/SiO2 catalysts with different Fe：O3 and ZnO loading was prepared by impregnation method. The catalyst samples were characterized by XRD, BET, and SEM techniques. It is reported that the catalytic performance of FeEOa-ZnO/SiO2 catalysts for the direct synthesis of isoamyl isovalerate from isoamyl alcohol with dioxygen. The reaction mechanism of synthesis was also explored. The result indicates that the dispersion of Fe203 on the SiO2 was enhanced and the particle size of Fe203 was reduced after the ZnO had been introduced into the catalyst. The FeEO3-ZnO/SiO2 catalysts had big Specific surface area, Mesopore volume and Mean pore diameter, which had the better catalytic performance than the FezO3/SiO2. Thereinto, The 6% Fe203-4% ZnO/SiO2 catalyst exhibited the best catalytic performance, the selectivity and yield of isoamyl isovalerate up to 54.5%, 31.4% respectively were achieved due to the cooperation between Fe203 and ZnO. The reaction condition was listed as follows at atmospheric pressure： catalyst dosage was 0.9 g, reaction temperature was 120℃, and reaction time was 9 h. As to the reaction mechanism, the isoamyl alcohol can transform into isoamyl isovalerate efficiently only if the catalyst cooperates with the dioxygen.