1079.    ---------------.  [FRANCIS, A. W.] Free Energies of Some Hydrocarbons.  Ind. Eng. Chem., vol. 20, 1928, pp. 277-282; Chem. Abs., vol. 22, 1928, p. 1131.

        From equations derived for the free energies of formation of CH₄, C₂H₆, octane, C₂H₄, C₂H₃, C₆H₆, PhMe, C₁₀H₈ and cyclohexane as functions of temperature it is shown that production of higher-paraffin hydrocarbons from lower ones is impossible, except with simultaneous production of still lower ones in at least equivalent amounts.  The catalytic formation of C₂H₄ in more than traces is impossible.  The direct removal of H from a paraffin to form an olefin with the same number of C atoms is possible only at high temperatures and to a very limited extent.  Synthesis of gasoline from water gas can take place only below about 450°.  Isomerization of olefins to naphthenes require temperatures below about 430°, while the production of aromatics requires 550°-900°.  In the Fischer synthesis of gasoline 8CO+17H₂→C₈H₁₈+8H₂O; ∆F=-338740+479.4T, which is negative up to 700° K. or 427° C.  The operating temperature for gasoline is 275°-300°.  Higher temperatures give lower hydrocarbons, especially CH₄, as should be expected.