Unique selectivity for the dimerization of propene on RhSn SiO2 catalysts: implications on the mechanism of CC bond formation and cleavage on bimetallic catalysts

Jamil Toyir, Michel Leconte, Gerald P. Niccolai, Jean Pierre Candy, Jean-Marie Maurice Basset*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

A series of bimetallic catalysts RhSnx SiO2 (x = 0.4, 0.7, 0.9, and 1.4) were synthesized by the reaction of the monometallic catalyst Rh SiO2 with Sn(n-butyl)4 under hydrogen. Various chemical and spectroscopic methods indicated that the metals present were fully reduced, and that tin atoms rest on the surface, very slightly increasing particle size and producing isolated rhodium sites. The catalytic reactions of propylene/hydrogen mixtures in the presence of these bimetallic catalysts are compared with those of the monometallic Rh SiO2 catalysts. The mechanistically interesting reactions observed are those of carbon-carbon bond formation and cleavage. For the monometallic catalyst, olefin homologation and hydrogenolysis were observed, reactions which invoked the transfer of C1 fragments from one olefin to another. For the bimetallic catalysts, a marked increase in the selectivity for C6 products was observed. The presence of hydrogen is necessary to this reaction but selectivity for C6 is enhanced when hydrogen is in deficit with respect to propylene. Selectivity for C6 increases with the surface rhodium to tin, Rhs Sn, ratio to a maximum at 0.9. Low temperature favors the formation of C6 and C2 products.

Original languageEnglish (US)
Pages (from-to)61-73
Number of pages13
JournalJournal of Molecular Catalysis. A, Chemical
Volume100
Issue number1-3
DOIs
StatePublished - Nov 23 1995

Keywords

  • Bimetallic catalysts
  • Dimerization
  • Propylene
  • Rhodium
  • Silica
  • Supported catalysts
  • Tin

ASJC Scopus subject areas

  • Catalysis
  • Process Chemistry and Technology
  • Physical and Theoretical Chemistry

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