稀土固体超强酸SO_4~(2-)/SnO_2-Nd_2O_3催化剂的软模板剂法制备及表征

以十二烷基苯磺酸钠(SDBS)为软模板剂,制备稀土固体超强酸催化剂SO~(2-)_4/SnO~2-Nd_2O_3。通过探针反应乙酸丁酯合成,得到该催化剂的最优制备条件为:SnCl_4浓度0.1mol/L,溶液与SDBS的质量比500,陈化时间24h,陈化时加入4%的Nd_2O_3(相对SnO_2),促进剂硫酸浸渍浓度3.0mol/L,焙烧温度550℃,焙烧时间3.0h。对该催化剂进行FTIR,TG-DTA,XRD表征,结果表明,稀土氧化物Nd_2O_3具有延缓SnO_2的晶化、固化SO~(2-)_4的作用,稀土改性后的催化剂稳定性有所提高;模板剂SDBS具有控制颗粒增长、调控颗粒形貌的作用,有利于产生较多酸活性位。

PREPARATION AND CHARACTERIZATION OF RARE EARTH SOLID SUPER ACID CATALYST SO42-/SnO2-Nd2O3 USING SOFT TEMPLATE AGENT

A rare earth solid super acid catalyst SO42-/SnO2-Nd2O3 was prepared using SDBS as soft template agent. The catalytic performance of the prepared catalyst was evaluated by esterification of acetic acid and n-butanol. The optimum conditions for the preparation of solid super acid SO42-/SnO2-Nd2O3 are as follows: a SnCl4 concentration of 0.1 mol/L, a mass ratio of solution to SDBS of 500, an aging time of 24 h, a Nd2O3 content of 4% (based on SnO2 content), an impregnating solution concentration of 3 mol/L, a calcination temperature of 550 ℃ and a calcination time of 3 h. The physicochemical properties of the catalysts were characterized by FT-IR, TG-DTA and XRD. The existence of Nd2O3 during aging could delay the crystallization of SnO2 and help the solidification of SO42- on the catalyst, thus the stability of the catalyst was improved by rear earth modification. Using SDBS template during catalyst preparation was helpful to adjust the catalyst particle feature for having more active acid sites.