3554.     VELDE, H.  [Methods for Working Up the Primary Products of the Synthesis Process and Their Application to the Treatment of Petroleum.]  Oel u. Kohle, vol. 37, 1941, pp. 143-148; British Abs., 1948, B, I, p. 280; Chem. Abs., vol. 35, 1941, p. 8268.

        Special refining method worked up by Ruhrchemie is similar to ordinary vapor-phase refining.  Raw gasoline before or, preferably, after final stabilization is heated to a high temperature below the cracking temperature and led over a special catalyst, unnamed, after which the vapors are cooled and passed over the same catalyst in a 2d step at a lower temperature.  Octane no. was improved by 8-24 points, the increase being independent of the original octane no.  It is indicated that this effect results from an isomerization of the original material, including both branching and a change in the position of the double bond.  A gasoline of 35% olefin content had an octane no. of 44, whereas, of 55% olefin content had an octane number of 41, other properties being substantially the same.  The octane nos. were increased to 52 and 61, respectively, by the method discussed.  The method increased the octane no. of a cracked gasoline from petroleum from 66 to 71.5.  Other methods, polymerization, aromatization, and cracking are briefly discussed.