A general approach for the calculation of thermodynamic equilibria of nonreactive and reactive multiphase systems is introduced. This method is based in the simulation of the dynamic evolution of a mixture from an arbitrary non-equilibrium state into the thermodynamic equilibrium. The advantage of the proposed method is that it is able to deal with complex multicomponent systems without numerical difficulties. The application of the method is shown at different equilibrium situations in the context of the butyl acetate synthesis.