ABSTRACT
At a very early stage in the development of a new chemical process, some thought must be given to phase equilibrium issues. The chemist, if running a liquid phase or gas-liquid reaction, must usually give at least some consideration to the pressure and temperature relationships. In 1985 a theoretical framework for assessment of reactive distillation was published. It includes as an example the separation of meta-xylene from paraxylene using organosodium compounds with crown ether chelating agents. A modest attempt to demonstrate the predictions experimentally also was reported. Activity coefficients exceed unity when the molecules are dissimilar and tend to aggregate more with each other than with the dissimilar molecules. Thus, pockets of high concentration of one component or the other are created on a molecular level. Occasionally, the forces attracting unlike pairs of molecules are stronger than forces between like molecules.
