3043. ----- [RUHRCHEMIE, A. G.] [Process for Obtaining Unsaturated Hydrocarbons by the Catalytic Hydrogenation of Carbon Monoxide.] German Patent Appl. R 109,864, R 567, filed Apr. 17, 1941 (Cl. IV d-12 o). TOM Reel 177, frames 1,728-1,730; Meyer Tran

PATENTS

3043. ----- [RUHRCHEMIE, A. G.] [Process for Obtaining Unsaturated Hydrocarbons by the Catalytic Hydrogenation of Carbon Monoxide.] German Patent Appl. R 109,864, R 567, filed Apr. 17, 1941 (Cl. IV d-12 o). TOM Reel 177, frames 1,728-1,730; Meyer Transl. PC-S-II, Fischer-Tropsch, vol. 1, chap. 55, 1948, p. 140.

The main patent specifies a synthesis gas mixture of 1 vol. each of CO and H₂ and then circulating 1 vol. of fresh gas with 2.5-4.0 vol. of recycle gas, at the same time shortening the period of gas contact with the catalyst as much as possible. This method reduces considerably the quantity of olefins in the reaction gas and has the further disadvantage that the olefins obtained have an unfavorable structure in that the terminal double bonds are replaced by those in the middle position. These disadvantages can be avoided, according to the addition patent, by gradually increasing the CO content in the gas mixture, by starting the operation with water gas and gradually allowing the dilution with inert gas to subside, or by beginning the synthesis with a synthesis gas having a CO:H₂ ratio of 1:1 and then gradually increasing the CO content. In these manners it is possible to prevent the reduction in the olefin content and the reversion of the terminal bonds. Furthermore, by increasing the operating time as the CO;H₂ ration is increased (from 1:1 to 1.3:1, for example), a corresponding increase in the olefin content of the product is obtained. Addition to German Patent Appl. R 108,263.