3659.     WENZEL, -----.  [State of the Synol Problem.]  TOM Reel 134, sec. II, No. 10; Rept. 326, Apr. 10, 1942, 33 pp.

        Since the Synol process was devised for producing high-molecular alcohols from CO and H₂, the problem has been to place it on an operating, commercial basis, 10,000 tons per yr., find the proper conditions for the synthesis, discover usable and economical methods for separating the hydrocarbons and alcohols in a pure enough state, and find applications for the products.  These problems appear to have been solved.  Alcohols can be obtained from synthesis or water gas of composition CO:H₂=1 : 0.75 or 1:1.  For best results, overheating of the catalyst should be avoided.  Pressures above 25 atm. are inadvisable.  Four stages of gas conversion are best, care being taken that the formation of CO₂ does not exceed 10% in order to produce the best yield of alcohol.  Temperature of conversion is about 190°-195° in the 1^st stage, and not exceeding 210°-225° in the other stages.  The layout for a Synol-synthesis plant with provision for a change over to diesel oil and gasoline production is described.  A plate converter was the most efficient for heat removal.  The best catalyst for the process appears to be the Leuna NH₃ fused Fe catalyst WK 17 of grain size 1-2 mm. reduced at 450° for 48 hr., with a H₂-load of 1:3,000 per hr.  It was found that this catalyst during the conversion forms hexagonal Fe carbide, Fe₂C, which at temperatures above 290° is transformed into inactive Hägg Fe₂C.  The 2d choice is a precipitation catalyst, No. 2643, with 3.7% Al₂O₃, 1% K₂O, and the remainder Fe.  Recently an Fe catalyst of high activity has been developed at Leuna containing small additions, 0.1% Sb, Ni, which may surpass the precipitation catalyst previously obtained.  The working up of the products is discussed at length to remove undesired impurities as acids, esters, aldehydes, and ketones.  Alcohols up to C₆ are separated by washing with water or MeOH solutions, the higher alcohols by the boric acid method.  Alcohols up to C₂₂ have been obtained.  The alcohols are thought to be mainly straight-chain and primary alcohols with the double bond at the end of the chain.  The products are believed to be suitable for making detergents, solvents, softeners for plastics, and varnish solvents.  Several patent applications listed.