2794.     ---------------.  [REICHL, E. H.]  Synthesis of Hydrocarbons and Chemicals From Carbon Monoxide and Hydrogen.  Isosynthesis.  U. S. Naval Tech. Mission in Europe Rept. 248-45, 1945, pp. 96-102; PB 22,841; TOM Reel 200.

        Synthesis of low-boiling isoparaffins, as discovered in the laboratories of the Kaiser Wilhelm Institute, is a variation of the MeOH or the isobutyl synthesis.  It operates at temperatures above those used in MeOH synthesis; although MeOH is believed to be an intermediate product.  The upper temperature range is limited by the decomposition of CO at about 550°; this limit is constant for all pressures.  The lower temperature limit is a function of the operating pressure; at 1,000 atm. the isosynthesis may be carried out at 400°; at 100 atm. a minimum of 450° required.  The kinetics of the synthesis is assumed to be as follows:  (1) Formation of MeOH from CO and H₂; (2) dehydration of alcohol and immediate reaction with additional CO and H₂ to isobutylene and higher isoparaffins; (3) polymerization of isobutylene possibly followed by hydrogenation of alkylate, or formation of dimethylether from MeOH through addition of CO and H₂.  At very high pressure the reaction proceeds as follows:  CH₃OH+CO+2 H₂→CH₃OCH₃+H₂O.  The catalyst is pure ThO₂ or better combined with a dehydrating catalyst such as Al₂O₃; the % of Al₂O₃ based on ThO₂ varies 30-40%.  A ThO₂-ZnO (1:1) catalyst does not give yields comparable to those with ThO₂-Al₂O₃; only 100 gm. per m.³, as compared to 130 gm. per m.³  The ThO₂ catalysts are virtually insensitive to S poisoning and their long life is remarkable.  The synthesis is carried out in a single pass with the feed gas containing CO-H₂ in the ratio 1:1.2; 70-75% conversion is obtained at average space velocities of about 1,350, 150 atm., and 450°.  The products obtained are mostly low-boiling isoparaffins with isobutane the largest individual component.