This paper reports on the removal of trace water from mixtures of n-butyl acetate, n-butanol, and acetic acid by pervaporation using a polyvinyl alcohol (PVA) membrane. The separations of binary (i.e., n-butyl acetate and water) and quaternary (n-butyl acetate, n-butanol, acetic acid, and water) mixtures were investigated. The quaternary mixtures are relevant to n-butyl acetate production by esterification via reactive distillation. A series of pervaporation experiments were performed, including a simulated production process in which the relationship between pervaporation time and water content in the feed was studied. The results show that the PVA membrane has very high permselectivity for water and maintains significant selectivity for a considerable period of time even when the water concentration is present at relatively high concentrations of water in organic mixtures.