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Methoxylation of α-pinene over heteropolyacids immobilized in silica

Paper ID Volume ID Publish Year Pages File Format Full-Text
42235 45916 2010 7 PDF Available
Title
Methoxylation of α-pinene over heteropolyacids immobilized in silica
Abstract

The methoxylation of α-pinene was studied using heteropolyacids immobilized on silica as catalysts, at 60 °C, being the α-terpinyl methyl ether the main product. Tungstophosphoric acid (PW), molybdophosphoric acid (PMo), tungstosilicic acid (SiW) and molybdosilicic acid (SiMo) were immobilized on silica by sol–gel method. It was observed that the catalytic activity of the silica-supported heteropolyacids decreases in the series: PW2_S > SiW_S > PMo_S > SiMo_S.A series of PW immobilized on silica with different PW loading were prepared. It was observed that the catalytic activity increases with the amount of PW immobilized on silica. However, at high amount of PW on silica, a decrease of the catalytic activity was observed.Good values of selectivity to α-terpinyl methyl ether (about 60% near complete conversion) were obtained with all catalysts.Catalytic stability of the PW2_S was evaluated by performing consecutive batch runs with the same catalyst sample. After the third batch it was observed a stabilisation of the initial activity.A kinetic model was developed assuming that the α-pinene is consumed according to the parallel reaction network. It was observed that the kinetic model fits the experimental concentration data quite well.

Graphical abstractThe methoxylation of α-pinene was studied using heteropolyacids immobilized on silica as catalysts, at 60 °C, being the α-terpinyl methyl ether the main product. Tungstophosphoric acid (PW), molybdophosphoric acid (PMo), tungstosilicic acid (SiW) and molybdosilicic acid (SiMo) were immobilized on silica by sol–gel method. It was observed that the catalytic activity of the silica-supported heteropolyacids decreases in the series: PW2_S > SiW_S > PMo_S > SiMo_S.Figure optionsDownload full-size imageDownload high-quality image (51 K)Download as PowerPoint slide

Keywords
Methoxylation; α-Pinene; Heteropolyacids; Silica
First Page Preview
Methoxylation of α-pinene over heteropolyacids immobilized in silica
Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 373, Issues 1–2, 31 January 2010, Pages 140–146
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis