The pervaporation process is an energy efficient and more environmentally friendly way of separating low molecular liquid components compared to traditional methods. In this work microsecond trajectories of molecular dynamics simulations with full-atomistic resolution model are used to study the behavior of benzene/methanol and cyclohexane/methanol mixtures in homopolymer (poly-m-phenylene isophthalamide) and its composite with MOF UiO-66 (NH2) for pervaporation separation. The equilibrium and dynamic properties of liquids molecules in polymer and composite systems are analyzed. We establish that the mobility of benzene and cyclohexane is significantly lower than that of methanol. However, these effects are caused by different reasons, namely, lyophilic and lyophobic interactions of benzene and cyclohexane with the polymer, respectively. According to our data, the inclusion of MOF in the polymer leads to an improvement of the pervaporation characteristics.