Development of a catalyst for conversion of syngas-derived materials to isobutylene. Quarterly technical report No. 13, April 1, 1994--June 30, 1994

Abstract

The goals of this project are to develop a catalyst and process for the conversion of syngas to isobutanol. The research will identify and optimize key catalyst and process characteristics. In addition, the commercial potential of the new process will be evaluated by an economic analysis. This report describes the preparation and testing of a variety of potential higher alcohols synthesis catalysts based on a bifunctional formulation consisting of a noble metal dehydrogenation function on a basic mixed metal oxide support. A pilot plant catalyst screening test using a 10/1 methanol/ethanol feed blend has been used to identify a new class of catalysts that afford higher selectivities and productivities. of the desired isobutanol and other C{sub 4+}, products than the Cu/Zn/Al oxide methanol synthesis catalyst that is being used as a baseline for this work. 2% Pd or Pt on a Zn/Mn/Zr oxide support and 2% Pd on a Zn/Mn/Cr support have given the best performances to date. In addition to isobutanol, these catalysts afford significant quantities of isobutyraldehyde and methyl isobutyrate. In order to elucidate the reaction pathway occurring with this class of catalyst, the 2%Pd on Zn/Mn/Zr oxide catalyst has been evaluated over a range of space velocities. It has been found that isobutanol and higher oxygenates yields increase with decreasing space velocity at ethanol conversions greater than 90%. This suggests that this catalyst is capable of converting methanol alone to higher alcohols. This is different from the result obtained with the Cu/Zn/Al oxide baseline catalyst, which showed no change in product yields at high ethanol conversions. Therefore, further effort will be focussed on the development of these noble metal/basic metal oxide catalysts for this application.