2672.     ---------------.  [PICHLER, H.]  [Discovery and Synthesis of New Paraffins of Very High Molecular Weight.]  Brennstoff-Chem., vol. 19, 1938, pp. 226-230; Petrol. Ztschr., vol. 34, No. 38, 1938, pp. 1-5; Chem. Abs., vol. 33, 1939, p. 120.

        In preliminary pressure hydrogenations with noble-metal catalysts, mixtures of 1:2 CO:H₂ heated to 140° in contact with reduced Ru oxide at 150 atm., while paraffins accumulate upon the catalyst.  These are completely soluble only in boiling ether, C₆H₆, or toluene and are separated with boiling toluene or xylene into fractions, the highest m. 120°-132°.  Repeated hydrogenation is made with 3 gm. catalyst in a heated-steel tube with continuous flow of the gas mixture exhausted at 1 l./hr. and starting at 15 atm. and 140°, the temperature is increased 10° each 24 hr.  Conversion begins at 160°, with 7% contraction in gas volume at 180°, increasing to 24% at 240°.  The solid and liquid reaction products, melting clear at 111°, are recovered in maximum yield at over 70% contraction at optimum conditions of 200° and 100 atm.  At 50-100 atm., over 90% of the O₂ in the CO forms H₂O; only below 50 atm. and above 200° are appreciable amounts of CO₂ formed.  Small amounts of fatty acids are formed with the reaction H₂O.  No decrease in catalyst activity is observed in 26 wk. of continuous use.  The oil-free solid paraffins constitute 60-70% of the product by the butanone method and m. 118°-119°.  Of these, 13% are insoluble in boiling C₆H₆ and m. 126°-128°.  The 53% soluble in boiling C₆H_6, m. 113°.  Subsequent extraction of the Ru catalyst with boiling toluene yields a paraffin m. 132°.  All the paraffins recovered, recrystallized, and washed with MeOH and distilled ether have the composition C_nH_2n+2.  Determination of molecular weight by boiling point elevation, mostly in toluene, show a range of 2,100-8,000, or 170-670 C atoms, for the 5 paraffins m. 123.5°-131.5° extracted from the catalyst.  These are situated upon the upper extension of the hyperbolic C atom; melting point curve of n-paraffins.  The 1:1 addition of kieselguhr to the Ru is without effect.  At atmospheric pressure, Pt produces no solid or liquid products, whereas Os and the remaining noble metals, beginning at 215°, produce small amounts of gaseous hydrocarbons other than CH₄ becoming inactive at 315° to produce only CH₄.  Under pressure, considerable yields are obtained with Rh and Os, the first giving contractions similar to Ru but with O-containing compounds, the latter reaching an activity at 220° to produce gaseous hydrocarbons.  Pt is even less active while only traces of hydrocarbons are obtained with Pd and Ir.