1029.    FISCHER, F., AND WEINROTTER, F.  [Thermal Cracking of Kogasin to Gaseous Olefinic Hydrocarbons.]   Brennstoff-Chem., vol. 21, 1940, pp. 209-217; Chem. Abs., vol. 35, 1941, p. 8253.

        Previous work is reviewed briefly.  The work of Fischer with Peters and Winzer is continued, and it is shown that at low-glow temperatures, with Pt wire spirals electrically heated, over 50% by weight of Kogasin II can be cracked into higher olefins.  Including C₂H₄, the content of the cracked gases is around 90% of unsaturated hydrocarbons.  Lowering of the glow-element temperatures does not increase the olefinic yield but increases the proportion of saturated hydrocarbons.  At higher temperatures about 70% olefinic yield is obtained but with more C₂H₄ at the expense of the higher members.  Similar results were obtained with a Pythagoras tube at 675°-760°, but only part of the Kogasin vapor was cracked in the recirculatory system, thereby interfering with further cracking of the initially formed olefins.  Cracking in vacuo gave no different results with the wire spiral.  A low-temperature fractionating column for analyzing the gas mixture is described in detail with operating procedure.  The Podbielniak dephlegmator for automatically maintaining desired temperatures with liquid air was employed.  Analytical curves are presented of the operation.  Sharp separations of the C₂, C₃, C₄ hydrocarbons were obtained.  Saturated and unsaturated hydrocarbons were separated by absorption of the latter in Hg(NO₃)₂ solution, the H₂ and CH₄ being separated previously and subjected to combustion analysis.  13 refs.