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采用浸渍法和混烧法,以γ-Al2O3或Al-MCM-41为载体分别负载B2O3和WO3活性组分,制备了可用于环己酮催化氧化合成ε-己内酯的固体酸催化剂,通过XRD、N2吸附-脱附、SEM和TEM等技术对催化剂进行了表征,并利用ε-己内酯合成实验评价了催化剂的性能。实验结果表明,混烧法制备的B2O3/γ-Al2O3催化剂对环己酮氧化合成ε-己内酯具有较高的活性。在B2O3/γ-Al2O3催化剂用量为0.8 g,第一步反应中丙酸65.19 g、双氧水25.00 g、48.13 kPa、3 h,第二步反应中环己酮5.40 g、50℃、常压、2 h的条件下,ε-己内酯的选择性和收率分别达95.80%和85.97%。在该催化反应中,催化剂的比表面积、孔径及孔体积等结构参数对催化活性影响不大,而高温焙烧过程中B2O3进入γ-Al2O3晶相后产生的晶格缺陷是该催化剂高活性的关键。
The solid acid catalysts which can be used for the catalytic oxidation of cyclohexanone to ε-caprolactone were prepared by impregnation method and mixed-calcination method, respectively, using γ-Al2O3 or Al-MCM-41 as carriers to support B2O3 and WO3 respectively. XRD, N2 adsorption-desorption, SEM and TEM were used to characterize the catalyst. The performance of the catalyst was evaluated by the synthesis of ε-caprolactone. The experimental results show that the B2O3 / γ-Al2O3 catalyst prepared by the mixed combustion method has high activity for the oxidation of cyclohexanone to ε-caprolactone. When the amount of B2O3 / γ-Al2O3 catalyst was 0.8 g, the first step reaction was 65.19 g of propionic acid, 25.00 g of hydrogen peroxide and 48.13 kPa for 3 h, and the second step was 5.40 g of cyclohexanone, 50 ℃ and atmospheric pressure for 2 h The selectivity and yield of ε-caprolactone reached 95.80% and 85.97% respectively. In the catalytic reaction, the structural parameters such as specific surface area, pore size and pore volume of the catalyst have little effect on the catalytic activity, and the lattice defects caused by the B2O3 entering the γ-Al2O3 crystal phase during high-temperature calcination are the key to the high activity of the catalyst .