fulltext.study @t Gmail

Supported Pt-Rh bimetallic catalysts as efficient systems for methylcyclohexane ring opening

Paper ID Volume ID Publish Year Pages File Format Full-Text
41142 45878 2012 9 PDF Available
Title
Supported Pt-Rh bimetallic catalysts as efficient systems for methylcyclohexane ring opening
Abstract

A series of supported Pt-Rh bimetallic systems was prepared either (i) by the refilling method (a surface redox reaction), or (ii) by the classical coimpregnation or (ii) by mechanical mixture of supported monometallic Pt and Rh catalysts and acidic support (chlorinated alumina). Two oxide supports were used for these preparations, i.e. alumina and silica. All these systems, largely characterized in a previous work dedicated to methylcyclopentane (MCP) hydrogenolysis, were studied for the methylcyclohexane (MCH) ring opening (RO) performed under high pressure (39.5 bar). During MCH transformation, synergetic performances were observed with some supported Pt-Rh bimetallic catalysts, since better performances in terms of activity and RO selectivity were obtained compared to those of monometallic Pt and Rh systems. The metallic particle size acts as a determining parameter modulating the catalytic properties, since the best RO performances were obtained on bimetallic catalysts presenting the largest particle sizes, for which a Pt surface enrichment and the presence of a Pt-Rh alloy were previously detected. On these bimetallic catalysts, the ring opening occurs mainly according to a bifunctional mechanism, the chlorinated alumina support bringing the required acidic function for the first isomerization step of C6 ring to alkylcyclopentanes further opened on the metallic function. The acidic function and the metal sites should not be necessarily in close vicinity since the mechanical mixture of non-acidic Pt-Rh/SiO2 catalyst with chlorinated alumina leads also to high RO selectivities. Finally, as for MCP ring opening, the refilling method allows synthesizing supported bimetallic Pt-Rh catalysts particularly efficient in terms of activity and RO selectivity.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (127 K)Download as PowerPoint slideHighlights► Supported Pt-Rh catalysts were prepared by refilling or coimpregnation method. ► Pt-Rh catalyst can be selective in MCH ring-opening (RO). ► The Pt-Rh particle size is a determining parameter modulating the RO selectivity. ► Chlorinated alumina brings the acidity sufficient for the isomerization step. ► Synergetic performances observed for Pt-Rh catalysts depending on particle size.

Keywords
Bimetallic catalysts; Ring opening; Methylcyclohexane; Platinum; Rhodium
First Page Preview
Supported Pt-Rh bimetallic catalysts as efficient systems for methylcyclohexane ring opening
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
Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volumes 415–416, 16 February 2012, Pages 80–88
Authors
, , , , , , , ,
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