范文编号:HG129 范文字数:12669,页数:28 摘 要:本文采用沉淀-浸渍法,通过改变硅锆原子量比、焙烧温度及焙烧时间三个变量制备一系列S2O82-/ZrO2-SiO2固体超强酸催化剂。通过单因素实验,考察了硅锆原子量比、焙烧温度及焙烧时间对蔗糖制备乙酰丙酸的影响。实验结果显示:随着硅锆比从3增加到5,乙酰丙酸的收率一直降低;随着焙烧温度从500℃升高到600℃,乙酰丙酸的收率开始时降低,到550℃以后升高;随着焙烧时间从2h增加到4h,乙酰丙酸的收率开始时升高,到3h以后降低。采用红外光谱仪及比表面仪对固体酸的结构和比表面积进行表征。实验结果显示:焙烧温度为500℃,焙烧时间为4h,硅锆比为4时,制备的催化剂的比表面积最大,催化活性最高;将该条件下制备的催化剂用于蔗糖及糠的水解反应,乙酰丙酸的收率分别17.4%和0.31%。 关键词:S2O82-/ZrO2-SiO2固体酸;乙酰丙酸;表征 Abstract: A series of S2O82-/ZrO2-SiO2 solid acid catalysts were prepared successfully by the method of precipitation-impregnation at different Si/Zr atom ratio, different roasting temperatures and different roasting times. Through the single factor test, we researched the effects of different Si/Zr atom ratio, roasting temperature and roasting time on the yield of Levulinic acid by sucrose and found that with the Si/Zr atom ratio improved from 3 to 5, the yield of LA was descend; with the roasting temperature improved from 500℃ to 600℃, the yield of LA was descend in the beginning, after 550℃ the yield was improved; with the roasting time improved from 2h to 4h, the yield of LA was improved in the beginning, after 3h the yield was descend. And solid superacid catalysts were characterized by means of IR and BET. The result indicate that:when the roasting temperature was 500℃, the roasting temperature was 4h, the Si/Zr atom ratio was 4, this kind of catalyst’s BET was the biggest, and its catalytic activity was the highest; this kind of catalyst for the hydrolysis of sucrose and bran, the yield of LA were 17.4% and 0.31%. Keywords:S2O82-/ZrO2-SiO2 Solid acid; Levulinic acid; Characterization
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