1809. ---------------. [KOCH, H.] [Some Properties of Synthetic Lubricants From Kogasin.] Brennstoff-Chem., vol. 18, 1937, pp. 121-127; British Chem. Abs., 1937, B, p. 408; Chem. Abs., vol. 32, 1938, p. 8756.

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Literature Abstracts

Previous work reviewed briefly. Essential differences from petroleum lubricants such as higher H₂ content and lower specific gravity are discussed. Various Kogasin products, a number of American and European petroleum products, and a polymerization product of 2-pentene are compared for specific gravity, average molecular weight, kinematic viscosity at 20° and 50°, and viscosity-temperature index. The first named with viscosity-temperature characteristics improved over those previously reported are residual distillation fractions boiling >200° and 250° at 15 mm. Hg. The 2-pentene product gave a very steep viscosity-temperature curve. At corresponding viscosities, Kogasin molecular weights are higher than those of the petroleum products. A wide range, 355-1,029, of average molecular weights is encountered. The Wijs I numbers increase with viscosity and for the better lubricating fractions are similar to those of petroleum products. Mild and strong hydrogenations of Kogasin lubricants with Co and Ni catalysts beginning with 100 atm. at 180° show corresponding decrease in I number with increase in absolute viscosity but with slight increase in viscosity-temperature index. Comparisons of two Pennsylvania oils, three Kogasin oils (one hydrogenated), and a commercial transformer oil for aging effects, light, and air treatment, showed sludge in the last after 8 days, considerable sludge in the winter-grade motor oil, but none in the summer-grade or Kogasin products even after 8 mo. Acid and saponification numbers show somewhat less increase in the synthetic products. Aging was greatly accelerated in the parallel tests by the presence of H₂O, even the summer oil formed sludge. Asphalt could not be precipitated from aged Kogasin oils by addition of petroleum ether, in contrast tot he natural oils; S is absent in the former. Subjected to the British Air Ministry test (2 6-hr. periods at 200° in air current) the aged Kogasin oils remained clear but colored, free from asphalt, doubled in viscosity (fourfold for the hydrogenated oil). In contrast, the aged petroleum oils became darker, cloudy, contained much asphalt, and increased to 8 times in viscosity. For both types of oils, the viscosity-temperature indexes increased slightly, the average molecular weight increased 10%, and Conradson C increased but remained lower in the Kogasin oils. Hydrogenation at 190°-200° with Ni catalyst after aging by this method restored the original properties of the Kogasin products. Practical motor tests showed 10% increase in viscosity after 3,800 km. acid and saponification numbers increased to 2.5 times. Conradson C increased from 0.125 to 0.22%, viscosity-temperature index changed from 1.85 to 1.83. Tests of low-viscosity oils, as transformer oils, show no depreciation in properties, the original Kogasin oil falling far within tolerances as to saponification and acid numbers, H₂SO₄ test, and with electrical breakdown of 180 kv. per cm. 15 refs.