Analytic expressions for equilibrium distributions of isomer groups in homologous series of alkanes, alkenes, and alkynes at a specified partial pressure of molecular hydrogen

摘要

The chemical equilibrium distributions of isomer groups in a homologous series of hydrocarbons can be calculated at a specified temperature, total pressure, and partial pressure of molecular hydrogen. If the standard Gibbs energies of formation of the successive isomer groups in the homologous series are given byA+Bn, wherenis the carbon number of the isomer group andAandBare functions of temperature only, the equilibrium distribution is given by an analytic function that depends only onAfor ideal gases. The analytic functions for the equilibrium mole fraction distributionsynand equilibrium mass fraction distributionswnare derived for the alkanes, alkenes, and alkynes. Equations for the mean carbon numbernmacr;, standard deviation sgr;, the carbon numbernmaxat whichwnis a maximum, and the masshyphen;average carbon numbernmacr;mare also derived.