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Direct addition of acetic acid to ethylene to form ethyl acetate in the presence of H4SiW12O40/SiO2

Paper ID Volume ID Publish Year Pages File Format Full-Text
43100 45955 2008 6 PDF Available
Title
Direct addition of acetic acid to ethylene to form ethyl acetate in the presence of H4SiW12O40/SiO2
Abstract

The direct addition of acetic acid to ethylene to form ethyl acetate over H4SiW12O40/SiO2 using SiO2 with various surface areas and mesopore sizes was studied. H4SiW12O40/SiO2 was superior in activity to conventional solid acids including H3PO4/SiO2, Nafion–SiO2, WO3–ZrO2, and unsupported H4SiW12O40. While the selectivity for ethyl acetate was more than 98% regardless of the catalyst, the activities were significantly different. Maximum activity was obtained when SiO2 having a high surface area and moderate pore size (ave. 6 nm) was utilized. The temperature-programmed desorption of benzonitrile technique and XRD both confirmed that this catalyst had a large amount of acid sites located on the outermost surface due to the high dispersion of H4SiW12O40. In contrast, H4SiW12O40/SiO2, with SiO2 of very small mesopores (3 nm) showed a very low activity, despite having the largest amount of acid sites located on the outermost surfaces. On this catalyst, diffusion of the reactant and product were slow due to the very small-sized mesopores. This limited diffusion rate results in its low activity.

Graphical abstractH4SiW12O40 supported on SiO2 was highly active for the direct addition of acetic acid to ethylene to form ethyl acetate. When SiO2 having a high surface area and moderate pore size (ave. 6 nm) was utilized, the maximum activity was obtained because of a large amount of acid sites located on the outermost surfaces.Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Benzonitrile-TPD; Heteropolyacid; Ethyl acetate
First Page Preview
Direct addition of acetic acid to ethylene to form ethyl acetate in the presence of H4SiW12O40/SiO2
Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 344, Issues 1–2, 15 July 2008, Pages 55–60
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis