磺酸基键合硅胶的制备及其酸催化性能研究

Synthesis and acid catalytic activity of HSO_3-functionalized silica

以氯丙基氯硅烷和苯基氯硅烷为偶联剂对硅胶进行表面改性,进一步磺化得到以磺酸基为活性中心的固体酸,磺化剂分别为硫酸和亚硫酸铵。以BET、红外光谱、总有机碳对固体酸及其前驱体进行了表征并测定了固体酸酸密度;利用总有机碳计算前驱体的键合量,苯基、氯丙基硅胶键合量分别为1.40 mmol/g,1.95 mmol/g;以这两种前驱体制得的固体酸酸密度分别为0.32 mmol/g,0.26 mmol/g;BET数据表明键合反应发生后苯基磺酸和丙基磺酸样品的比表面积由521 m2/g降至406 m2/g,432 m2/g。将制得固体酸应用于乙酸丁酯的合成,经五次使用仍保持较高转化率。

The phenyl and chloropropyl silica derived from chlorosilane were applied to synthesize HSO3-functionalized silica by using H2SO4 or （NH4）2SO3 as sulfonation agents. The solid acid and their precursors were characterized by BET, IR, TOC （total organic carbon）. The surface coverage density of phenyl-silica and chloropropyl-silica are 1.40 mmol/g and 1.95 mmol/g, while the acid exchange capacities are 0.32 mmol/g and 0.26 mmol/g, respectively. The specific surface area of phenyl-silica and chloropmpyl-silica respectively decreased slightly from 521 m2/g to 406 m^2/g and 432 m^2/g. The solid acids were used as catalysts in the synthesis of acetic acid butylester. The results indicate that the catalysts can be reused 5 times with a high conversion ratio.