2191.     MATIGNON, C.  [Physicochemical Study of Some Organic Syntheses.]  Bull. soc. chim., vol. 37, 1925, pp. 825-836; Chem. Abs., vol. 20, 1926, p. 38.

        It is readily possible to decide from the heats of reaction and van’t Hoff’s equation and the principles of equilibrium whether certain synthetic reactions, starting with simple gaseous substances, could be realized, granted a suitable catalyst, or would be entirely unattainable without the introduction of energy in some form.  For example, CO+2 H₂=MeOH+27.2 cal. K=(p₁Xp₂²)/x, where p₁, p₂ and x are the pressures of the substances concerned in atmospheres.  K can be calculated for any other temperature by the relation log K=-27,200/457 T+3.5 log T+4.3.  Then for assumed, but possible, values for p₁=p₂=50 atm., x=1.8X10³.  At p₁=p₂=1, x=1/70.  At 327°, the equilibrium is less favorable but still possible, while at 427° it would be virtually useless.  Similar calculations are used to show that primary aliphatic alcohols, AcOH and EtCO₂H could be made from CO and H₂ but that C₂O could not be.  From C₂H₄ and H₂ the saturated hydrocarbons could be formed, also Me₂CO and PrOH from C₂H₄, CO, and H₂.  From CH₄ and H₂O, CO and H₂ might be made at a rather high temperature, but CH₄ and CO and H₂ could not give EtOH nor could CH₄ alone give C₂H₆, etc.  Since in general any catalyst that assists a reaction toward equilibrium also assists the opposite reaction toward equilibrium, the search by catalysts for reactions shown by the above methods to be possible can be simplified by searching for decomposition catalysts for the final substances desired.  For example, find catalysts for the decomposition of AcOH to CO and H₂, and the same catalysts will serve for the synthesis of AcOH from CO and H₂.