Distillation near-isothermal process

Theoretically, catalytic distillation can overcome limitations in a typical two-step process consisting of reaction followed by distillation or separation. Often, a two-step process is limited by chemical equilibrium, heat transfer, mass transfer, or some combination of these. Catalytic distillation can overcome many of these constraints by simultaneously separating products from reactants, maintaining nearly isothermal operation and lowering the external ratio of reaction diluents. 

The argument is sometimes advanced that isobaric VLE data are more useful for process design, because separation processes are more nearly isobaric than Isothermal. This argument Ignores the fact that pressure drops in distillation columns can be substantial, and that they are accounted for in modern design procedures. The best thermodynamic tool for low-pressure distillation column design is an expression for in terms of T and x, with values for the parameters determined from carefully executed Isothermal VLE experiments. 

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