1239.    ---------------.  [GREAT BRITAIN FUEL RESEARCH BOARD.] Synthesis of Hydrocarbons From Carbon Monoxide and Hydrogen.  Rept. for the Year Ended Mar. 31, 1937, pp. 141-147.

        Laboratory investigation on the synthesis of hydrocarbons from CO and H₂ has been directed mainly to determine the influence of the % of ThO₂ promoter on the activity of the Co catalyst, and the effect on the yield of hydrocarbons of changing the ratio CO:H₂.  No conclusions have been reached.  As to the mechanism of the synthesis reaction, the evidence points toward the Fischer carbide theory, although an alternative theory is postulated that the CO molecules are first linked to the catalyst surface, forming a bond similar to that existing in a Co carbonyl molecule, except that the metal atom is not detached from the lattice.  The H₂ absorbed on adjacent Co atoms may then react with the absorbed CO, attacking either the O₂ or the C atom.  In the latter case, HCHO would be formed as an intermediate product.  Neither of the above hypotheses explains how the methylene or other radicals first formed link up to give the long hydrocarbon chains.  A plant, large enough to convert 100-150 cu. ft. of a mixture of H₂ and CO per hr. into hydrocarbons has been designed and constructed.  A flow diagram of the plant is shown.  Catalyst cooling is accomplished by circulating hot water under pressure through horizontal tubes in the catalyst bed.  Details of catalyst preparation are presented, and the importance of washing the precipitated catalyst with boiling H₂O is emphasized.  With the unwashed catalyst no contraction took place, even at a temperature of 238°, whereas with the washed catalyst a contraction of 65% at 198° took place and was maintained for 24 hr.  At an equivalent gas rate per gm. of catalyst, the catalyst that had been washed and electrodialyzed brought about a contraction of 71% at 193°.  Some difficulty was found in transferring the catalyst preparation from the laboratory to the larger scale, the causative variables have not been determined.