Pervaporation of the quaternary mixture present during the esterification of lactic acid with ethanol

Pervaporation of the quaternary mixture involved in the synthesis of ethyl lactate, water/ethanol/ethyl lactate/lactic acid, has been investigated. Pervaporation experiments were performed with the commercial hydrophilic membrane PERVAP® 2201 at 327.15 and 348.15 K. PERVAP® 2201 membrane was previously tested for some of the binary mixtures present in the quaternary mixture showing high water selectivity. The effects of pervaporation temperature and water and lactic acid feed concentration on pervaporation performance have been studied in terms of permeation flux and permeance. The concentration range covered in this work was 12–63 wt% for water and 9–30 wt% for lactic acid. The permeation flux was found to increase with water feed concentration and temperature. However, the permeation flux was nearly constant when varying lactic acid concentration in the feed. Water permeance increased with water feed concentration but a slight dependence on temperature was observed.