Synthesis of ethanol from syngas over Rh/MCM-41 Catalyst: Effect of water on product selectivity

Luis Lopez, Jorge Velasco, Vicente Montes, Alberto Marinas, Saul Cabrera, Magali Boutonnet, Sven Järås

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

The thermochemical processing of biomass is an alternative route for the manufacture of fuel-grade ethanol, in which the catalytic conversion of syngas to ethanol is a key step. The search for novel catalyst formulations, active sites and types of support is of current interest. In this work, the catalytic performance of an Rh/MCM-41 catalyst has been evaluated and compared with a typical Rh/SiO2 catalyst. They have been compared at identical reaction conditions (280 °C and 20 bar), at low syngas conversion (2.8%) and at same metal dispersion (H/Rh = 22%). Under these conditions, the catalysts showed different product selectivities. The differences have been attributed to the concentration of water vapor in the pores of Rh/MCM-41. The concentration of water vapor could promote the water-gas-shift-reaction generating some extra carbon dioxide and hydrogen, which in turn can induce side reactions and change the product selectivity. The extra hydrogen generated could facilitate the hydrogenation of a C2-oxygenated intermediate to ethanol, thus resulting in a higher ethanol selectivity over the Rh/MCM-41 catalyst as compared to the typical Rh/SiO2 catalyst; 24% and 8%, respectively. The catalysts have been characterized, before and after reaction, by N2-physisorption, X-ray photoelectron spectroscopy, X-ray diffraction, H2-chemisorption, transmission electron microscopy and temperature programmed reduction.

Original languageEnglish
Article numberA08
Pages (from-to)1737-1755
Number of pages19
JournalCatalysts
Volume5
Issue number4
DOIs
StatePublished - 2015

Bibliographical note

Publisher Copyright:
© 2015 by the authors; licensee MDPI, Basel, Switzerland.

Keywords

  • Ethanol
  • Rh/MCM-41 catalyst
  • Syngas
  • Water vapor

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