2414.     NEGISHI, R., KIMURA, O., AND KAMIIKE, O.  Hydrocarbons From Carbide.  Rev. Phys. Chem. Japan, vol. 15, 1941, pp. 31-41; Chem. Abs., vol. 35, 1941, p. 6501.

        Many hydrocarbons can be synthesized directly from CaC2, without first preparing C2H2 to be polymerized later.  The free energy of formation is calculated for a number of chain hydrocarbons and cyclic hydrocarbons, both from CaC2 and H2O to produce hydrocarbon and CaO and also from CaC2, CO, and H2 to form hydrocarbon and CaCO3.  The free-energy changes are very large, especially for the hydrocarbons with the greater number of C atoms.  The ∆F at 300 is 83.5 kg.-cal. greater for the preparation of benzene from CaC2 and H2O, than from C2H2, and the increase in ∆F is even larger for similar syntheses of 1,3-butadiene or n-octane.  The affinity of CaC2 for H2O, and of CaO formed during the reaction for CO2, may increase the reaction rate by effectively removing these reaction products.  The temperature coefficients of the reactions in which CaCO3 is formed are greater than those in which CaO is formed.  The addition of CaC2 and the greater reactivity of nascent C2H2 molecules result experimentally in a faster rate and greater yield of polymerized C2H2 than is obtained by catalytic polymerization with a Co-Ni-Cr2O3 clay catalyst or a Fe-Ni-kieselguhr catalyst.