Preparation and Properties of a Nano-catalyst for Synthesizing Chlorine-free Benzaldehyde

运用共沉淀法制备了系列锌锰复合纳米催化剂,并用于气相催化加氢苯甲酸合成无氯苯甲醛。经XRD,TEM,BET,IR等表征技术表明,其主要物相为ZnMnO3、ZnO和MnO2,粒径范围在80~200 nm.实验室及单管小试结果表明,该纳米催化剂不但具有很高的催化选择性,而且降低了反应温度。当反应温度为370±10℃、酸液时空速0.1 h-1、氢气时空速650±50 h-1时,苯甲酸的转化率高达99.0%,苯甲醛的选择性为94.5%。同样条件下,取140 kg的催化剂在厦门涌泉集团做了中试,得到苯甲酸的转化率为98%,苯甲醛的选择性为83.2%。A series of industrial catalysts for hydrogenation of benzoic acid to chlorine-free benzaldehyde were prepared by co-precipitation method.Characterization with XRD,TEM,BET and IR shows that,the main phase is ZnMnO_3 accompanied with ZnO and MnO_2 and the particle size ranges from 80 nm to 200 nm.The hydrogenation reaction temperature over this catalyst is considerably lowered as compared with that on traditional catalyst.In hydrogenation reaction of benzoic acid,99.0% conversion and 94.5% selectivity to benzaldehyde were achieved under the conditions that reaction temperature,gas hourly space velocity(GHSV) and liquid hourly space velocity(LHSV) were controlled at 370±10 ℃,0.1 h~(-1),and 650±50 h~(-1) respectively.At Xiamen Yongquan Spice Company,the catalyst weighed 140 kg was applied in pilot plant scale under similar conditions described above,and the selectivity to benzaldehyde was 83.2%,while conversion of benzoic acid reached nearly 98%.福建省重点科技项目(99-Z-53)~