کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5142140 1496026 2017 11 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Some physico-chemical properties and catalytic activity of sulfate ion supported on WO3/SnO2 catalyst
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی (عمومی)
پیش نمایش صفحه اول مقاله
Some physico-chemical properties and catalytic activity of sulfate ion supported on WO3/SnO2 catalyst
چکیده انگلیسی
Solid acid catalyst 15 wt%WO3/SnO2 was synthesized and loaded with 15 wt%SO4. The obtained catalyst was calcined at 400, 500, 650 and 800 °C. The prepared catalysts were characterized by TG-DTA, XRD, FTIR and N2 adsorption at −196 °C. The surface acidity was measured by non aqueous potentiometric titration and FT-IR spectra of chemisorbed pyridine. The catalytic performance was evaluated on the esterification of propionic acid with n-butanol in liquid phase. The TG-DTA analysis shows that the decomposition of sulfate species occurred at >500 °C. XRD measurements showed that WO3 dispersed completely on the surface of SnO2 and that the sulfating of WO3/SnO2 tends to hinder the crystallization of SnO2. The specific surface area, total pore volume and micropore volume are increased with increasing thermal treatment up to 500 °C, and then decreased gradually with a further increase in calcination temperature. The prepared catalysts possess very strong acid sites and contain both Brønsted and Lewis acid sites. The total surface acidity decreased with raising of the calcination temperature. The highest conversion of propionic acid was for 400 °C product, and decreased with an increase in calcination temperature. The effect of the reaction parameters, i.e., time of reaction, reaction temperature, and reactant molar ratio and the weight of the catalyst were also studied. The reaction obeys the second order kinetic equation with respect to propionic acid concentration. Brønsted and Lewis acid sites appeared to be needed for catalytic activity in n-butyl propionate formation.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Arabian Journal of Chemistry - Volume 10, Supplement 1, February 2017, Pages S439-S449
نویسندگان
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