Preparation, Characterization of Superacid SO_4^(2-)/ZrO_2-SiO_2 and Its Activity on Catalytic Synthesis of Methyl p-Nitrobenzoate  

作　　者：王刚 TAO Liya HOU Xin CAO Hi DONG Cheng NIE Wo XU Jun 张立庆 

机构地区：[1]College of Biological and Chemical Engineering, Zhe Jiang University of Science and Technology

出　　处：《Journal of Wuhan University of Technology(Materials Science)》2014年第5期895-899,共5页武汉理工大学学报（材料科学英文版）

基　　金：Supported by Natural Science Foundation of Zhejiang Province(No.Y404082)

摘　　要：Solid superacid SO42-/ZrO2-SiO2 was prepared by dip-impregnation method, and its catalytic activity was tested with esterification of p-nitrobenzoic acid and methanol. The optimum conditions were also found, that is, the molar ratio between silica and zirconia was 10：1, the calcination temperature was 550 ℃ and the soaked consistency of H2SO4 was 1.0 mol.L-1. Under the conditions that the ratio of methanol to aeid（mL/ g） was 12：1, the amount of catalyst was 0.5 g, the reaction time was 5 h and the stirring speed was 800 r.min-1, the yield of methyl p-nitrobenzoate could reach up to 90.5%. Then the characterizations of cataslyst, including the acidity and types of acidic centers, specific surface area and surface structure was respectively examined by Hammer indicator, in-situ pyridine IR, BET method, FT-IR（KBr）, transmission electron microscope （TEM）, and X-ray diffraction （XRD）. The results showed that the catalyst SO42-/ZrO2-SiO2 was superacid with high specific surface area due to Ho〈-12.70. It contained acidic sites of Lewis and BrФnsted, and its surface structure changed after esterification. The zirconia crystal was mainly tetragonal and silica crystal was not found.Solid superacid SO42-/ZrO2-SiO2 was prepared by dip-impregnation method, and its catalytic activity was tested with esterification of p-nitrobenzoic acid and methanol. The optimum conditions were also found, that is, the molar ratio between silica and zirconia was 10：1, the calcination temperature was 550 ℃ and the soaked consistency of H2SO4 was 1.0 mol.L-1. Under the conditions that the ratio of methanol to aeid（mL/ g） was 12：1, the amount of catalyst was 0.5 g, the reaction time was 5 h and the stirring speed was 800 r.min-1, the yield of methyl p-nitrobenzoate could reach up to 90.5%. Then the characterizations of cataslyst, including the acidity and types of acidic centers, specific surface area and surface structure was respectively examined by Hammer indicator, in-situ pyridine IR, BET method, FT-IR（KBr）, transmission electron microscope （TEM）, and X-ray diffraction （XRD）. The results showed that the catalyst SO42-/ZrO2-SiO2 was superacid with high specific surface area due to Ho〈-12.70. It contained acidic sites of Lewis and BrФnsted, and its surface structure changed after esterification. The zirconia crystal was mainly tetragonal and silica crystal was not found.

关 键 词：solid superacid methyl p-nitrobenzoate in-situ pyridine IR X-ray diffraction 

分 类 号：O643.36[理学—物理化学] TQ241.15[理学—化学]