Abstract
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 °C and the soaked consistency of H2SO4 was 1.0 mol·L−1. Under the conditions that the ratio of methanol to acid(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 Hammett 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 Brψnsted, and its surface structure changed after esterification. The zirconia crystal was mainly tetragonal and silica crystal was not found.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: Journal of Wuhan University of Technology-Mater. Sci. Ed.
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.