Effect of dead-space on the kinetics of gaseous association reactions

Abstract

A theoretical account is given of the detailed kinetic behaviour of a generalized gaseous association reaction in an experimental system with dead-space. Expressions are derived for the partial pressures of the reactants in the reaction vessel at any time, and it is shown that integrated function plots using these pressures should be accurately linear. This is in distinct contrast to a decomposition reaction, where function plots using the actual reactant pressure are curved. If the reactant pressures are approximated by ideal expressions without allowance for dead-space the function plots will be curved, probably to a marked extent. This practice is therefore not recommended, especially since the calculation of the exact reactant pressures is simple. For stoichiometric mixtures, or for the association reactions of a single gas, linear plots can also be obtained by using approximate reactant concentrations calculated from expressions involving the final pressure.