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Title: Improved Fischer-Tropsch synthesis catalysts for indirect coal liquefaction: Final quarterly technical progress report No. 4 for the period 1 July to 30 September 1986

Technical Report ·
OSTI ID:6956188

We have made significant progress in developing novel catalysts for the Fischer-Tropsch synthesis (FTS). The stoichiometries of the cluster synthesis and surface-confining reactions on an alumina support for aluminum tetra- and aluminum hexa-ruthenium hydridocarbonyl cluster catalysts were determined by gas evolution measurements. Characterization with FTIR and NMR spectroscopy of the cluster intermediates is also consistent with the observed cluster catalyst stoichiometry, Al/sub 2/O/sub 3/-Al(C/sub 2/H/sub 5/)-Ru/sub 4/H/sub 3/(CO)/sub 12/ and Al/sub 2/O/sub 3/-Al(C/sub 2/H/sub 5/)-Ru/sub 6/H(CO)/sub 18/. Activation of the surface-confined supported cluster complex by heating to 573 K in inert gas or hydrogen is likely to produce a stabilized cluster catalyst due to affinity of aluminum for alumina and the strength of the aluminum-ruthenium bonds relative to ruthenium-ligand bonds. The cluster catalysts were tested for FTS in 2:1 H/sub 2/:CO syngas at 523 K and 1 atm. The 0.6 wt % Ru/sub 4/ catalyst had superior activity and about the same selectivity through C/sub 8/ hydrocarbons as a commercial alumina-supported 0.5 wt % Ru catalyst. The 1.2 wt % Ru/sub 6/ catalyst was less active but had similar selectivity. Substantial changes in selectivity of standard-fused iron catalysts were found following treatment to uniformly chemisorb submonolayer quantities of sulfur. Approximately 40% of a monolayer of sulfur was slowly adsorbed at 473 K on the potassium-promoted fused iron catalyst following reduction and passivation by accumulation of a surface layer of carbon and CO. The passivating layer was removed and the sulfur was locally dispersed by heating to 1000 K in hydrogen. The treated catalyst had a three-fold reduction in methane selectivity-relative to untreated reduced fused iron at 573 K, and the C/sub 2/ olefin yield approached 100%. 7 refs., 1 fig., 3 tabs.

Research Organization:
SRI International, Menlo Park, CA (USA)
DOE Contract Number:
AC22-85PC80016
OSTI ID:
6956188
Report Number(s):
DOE/PC/80016-T2; ON: DE87005037
Resource Relation:
Other Information: Portions of this document are illegible in microfiche products
Country of Publication:
United States
Language:
English