Solvent-free enzymatic esterification of pentyl propionate. Comparison of results using two types of reactors: BSTR and PBR

Abstract

This paper addresses the solvent-free esterification of pentan-1-ol with propionic acid to produce pentyl propionate, using Lipozyme®435 as catalyst. A batch stirred tank reactor (BSTR) and a packed bed continuous reactor (PBR) are tested and compared in technical and economic terms. The effect of some variables such as temperature, reagents proportion, catalyst load and flow rate is analyzed. High conversions can be achieved in both reactors, evidencing the technical feasibility of the solvent-free reaction in both batch and continuous operation. Enzyme deactivation occurs as a result of the synergic effect of high temperatures (>70 °C) and low alcohol/acid ratio. At equal reaction conditions, enzyme deactivation is much stronger in the batch reactor, indicating a higher enzyme stability in the packed bed reactor.