CARLA S.M. PEREIRA, ALÍRIO E. RODRIGUES*
*Corresponding author
Universidade do Porto, LSRE – Laboratory of Separation and Reaction Engineering – Associate Laboratory LSRE/LCM Faculdade de Engenharia, Rua Dr. Roberto Frias, 4200-465 Porto, Portuga

Abstract

Chromatographic reactors, where reaction and separation processes are combined into single equipment, are a way of achieving better energy efficiency, productivity improvement and lower solvent consumption. In this perspective two innovative technologies are presented: the Simulated Moving Bed Reactor (SMBR) and the recently developed Simulated Moving Bed Membrane Reactor (PermSMBR). Potential applications for these technologies are addressed and their performance for the synthesis of some important oxygenates, such as acetals (1,1-diethoxyethane, 1,1-dibutoxyethane, 1,1-dimethoxyethane) used on diesel blends and ethyl lactate used as green solvent. Future challenges are highlighted.

INTRODUCTION

Traditionally, compounds involving equilibrium limited reactions (as acetals, esters, ethers, among others) are synthesized in a batch reactor fed with excess of one of the reactants and followed by various separation units (mainly energy-intensive distillation steps) in order to recover the desired product, to remove the by-product(s), and to recycle the unconverted reactants to the reactor, which represents high costs (Figure 1). Process intensification, regarding the integration of reaction and separation steps into a single unit, provides the most feasible engineering solution for sustainable synthesis of this type of compounds since the products are separated as they are formed overcoming by this way the equilibrium conversion, leading to higher yields and purities of the final products. In particular, chromatographic reactors have arisen substantial interest in the chemical engineering research and industry. The simplest way of operating a chromatographic reactor is in batch mode, which was patented in the early 1960s (1, 2). However, due to the drawbacks associated with a batch process such as low yields and high product dilution, ove ...