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PtSn/SiO2 catalysts prepared by controlled surface reactions for citral hydrogenation in liquid phase

Paper ID Volume ID Publish Year Pages File Format Full-Text
44327 46015 2007 11 PDF Available
Title
PtSn/SiO2 catalysts prepared by controlled surface reactions for citral hydrogenation in liquid phase
Abstract

Bimetallic PtSn/SiO2 catalysts with broad Sn/Pt atomic ratios were prepared by an organometallic method using a controlled surface reactions (CSRs) between hydrogen adsorbed on silica-supported Pt and tin tetraethyl. The catalytic behavior of these catalysts was studied in citral hydrogenation in liquid phase carried out at 70 °C and atmospheric pressure. The catalysts were characterized by test reactions of the metallic phase (cyclohexane dehydrogenation (CHD), and cyclopentane hydrogenolysis (CPH)), CO chemisorption and Mössbauer spectroscopy. All these results clearly showed that tin was introduced exclusively into platinum. Results of citral hydrogenation show that the contribution of different reaction routes strongly depends on the metallic loading of both Pt and Sn, thus giving either a high selectivity to citronellal (CAL) or to unsaturated alcohols nerol + geraniol (UA), for monometallic and bimetallic catalysts, respectively. The citronellal cyclization resulting in the formation of isopulegol, was almost negligible because of the low concentration of acidic sites of the support. It was observed that the higher the Pt loading, the lower the Sn/Pt atomic ratio required to get higher UA selectivities. Products of undesirable side reactions were detected in trace amount. The results of CO chemisorption and CHD test reaction provided unambiguous prove that, due to the addition of tin, the catalytic properties of the metallic phase have been modified. Thus, results show that modified catalysts are highly selective for the hydrogenation of the carbonyl group.

Graphical abstractBimetallic PtSn/SiO2 catalysts with broad Sn/Pt atomic ratios were prepared by controlled surface reactions (CSRs). The catalytic behavior of these catalysts was studied in citral hydrogenation in liquid phase carried out at 70 °C and atmospheric pressure. Results of citral hydrogenation show that the contribution of different reaction routes strongly depends on the metallic loading of both Pt and Sn, thus giving either a high selectivity to citronellal (CAL) or to unsaturated alcohols nerol + geraniol (UA), for monometallic and bimetallic catalysts, respectively.Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
PtSn/SiO2 catalysts; Selective hydrogenation; Citral hydrogenation; Controlled surface reactions
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PtSn/SiO2 catalysts prepared by controlled surface reactions for citral hydrogenation in liquid phase
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 326, Issue 1, 30 June 2007, Pages 37–47
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us