Trifunctional Catalysts for Conversion of Syngas to Alcohols. Third Quarterly Report, March 1-May 31, 1985

摘要

An exploratory series of prepared and purchased rhodium catalysts have been tested for CO hydrogenation with interesting results. The results are summarized in tabular form for typical test conditions, 250 exp 0 C, 30 atmospheres pressure, 2 H sub 2 /CO at 4000 GHSV. Rhodium-alumina catalysts are moderately active, e.g., 6% CO conversion. Selectivity of CO to oxygenates is typically 30% with the balance mostly methane. An important feature is that 75% of the oxygenates are C/sub 2+/, including ethanol, acetic acid and methyl and ethyl acetates. The addition of sodium or potassium lowered the activity considerably. However for the highest Na level tested, (2% wt. Na) selectivity to oxygenates increased to 55 to 75%, though CO conversion was only about 1% to 2.5%. The addition of 1% Mn to Rh-Al sub 2 O sub 3 decreased activity with no increase in selectivity. A higher Mn loading decreased activity further without affecting selectivity. This is quite contrary to previous observations on the effect of Mn on SiO sub 2 -based Rh catalysts. Two catalysts containing SiO sub 2 gave relatively high selectivity. One, a Rh-Mn-Mo-SiO sub 2 catalyst, similar to the Van den Berg catalyst, gave 6% conversion and 50 to 70% selectivity to oxygenates. Another catalyst, Rh-Mn-Mo- Florisil (SiO sub 2 -MgO), gave the highest selectivity found so far, 93%, though at low conversion. A Pd-active carbon catalyst produced only methanol (no CH sub 4 or C sub 2 H sub 5 OH). The above catalysts now provide a basis for experiments relating composition to performance, to provide samples for study by instrumental techniques, and to provide a rational basis for additional catalyst preparations. 3 figs., 6 tabs. (ERA citation 10:033418)