WO_3/SBA-15催化剂的制备及其氧化脱硫性能

以介孔SBA-15分子筛为载体,采用两种不同钨源(H_2WO_4和H_2C_2O_4、H_2WO_4和H_2O_2)通过浸渍法制备了WO_3/SBA-15催化剂;采用X射线衍射和傅里叶变换红外光谱法对介孔SBA-15分子筛和WO_3/SBA-15催化剂进行了表征;以硫含量为500μg/g的模拟汽油为原料进行氧化脱硫反应,反应后油相用1-甲基-2-吡咯烷酮萃取,考察了萃取剂用量、催化剂用量、氧化反应温度和反应时间对脱硫率的影响。表征结果显示,WO_3/SBA-15催化剂有规则的二维六方介孔结构,WO_3在载体上高度分散。实验结果表明,以H_2WO_4和H_2C_2O_4为钨源制备的WO_3/SBA-15催化剂的脱硫效果较好,在反应温度320 K、反应时间120 min、模拟汽油60 mL、催化剂用量0 12 g、双氧水0.57 mL、萃取剂与模拟汽油体积比0.50、萃取时间5 min的条件下,脱硫率可达94.05%。

Preparation and Oxidative Desulfurization Performance of WO_3/SBA-15 Catalyst

WO_3/SBA-15 catalysts were prepared by impregnation from two alternative tungsten sources(tungstic acid, oxalic acid and tungstic acid, hydrogen peroxide) with mesoporous SBA-15 molecular sieves as support. The catalysts were characterized by means of XRD and FTIR. Oxidative desulfurization of model gasoline(sulfur content 500 μg/g) was catalyzed by the two WO_3/SBA-15 catalysts separately and the oil phase was extracted by 1-methyl-2-pyrrolidone after reaction. Effects of extractant dosage, catalyst amount, reaction temperature and time on the desulfurization rate were investigated. WO_3/SBA-15 catalysts still kept ordered two-dimensional hexagonal mesoporous structure of the support, and WO3 species was highly dispersed on it. The catalyst prepared from tungstic acid and oxalic acid showed higher activity in oxidative desulfurization than the counterpart. The optimized oxidative desulfurization conditions were: reaction temperature 320 K, reaction time 120 min, model gasoline 60 mL,catalyst dosage 0.12 g and 30%(w)H_2O_2 solution 0.57 mL. After seperation of catalyst,desulfurization rate of gasoline was determined by extraction with 1-methyl-2-pyrrolidone as extractant, volume ratio of extractant to model gasoline 0.50, extraction time 5 min, the desulfurization rate was 94.05%.