Vapor phase esterification using a CHA type of zeolite membrane

• CHA zeolite membrane showed a high water permeance of 2 × 10−7 mol/(m2 s Pa) at 130° C.
• CHA membrane showed a selectivity as high as 2850 for H2O/EtOH at 130° C.
• Conversion in vapor-phase esterification using a CHA membrane increased over the equilibrium.

Vapor phase esterification in a chabazite (CHA) zeolite membrane reactor was attempted not only to improve the productivity but also to avoid the use of liquid strong acid. CHA zeolite membrane was successfully prepared on a porous alumina tube by hydrothermal synthesis, showing a water permeance of ca. 2 × 10−7mol/(m2·s·Pa) and a selectivity of 2850 for H2O/EtOH at 130° C. As the alternate of the liquid acid, proton exchanged mordenite (H-MOR) was selected as a solid catalyst, where the esterification was found to be explained according to the Eley-Rideal mechanism. When vapor-phase esterification was carried out in a double tube type membrane reactor, some equilibrium shift was observed; this was achieved by continuous and selective water removal along the reactor length. Further, it was demonstrated that a simulation model for the membrane reactor, established on the assumption that the ideal conditions could be applied, described the reactor performance well.

The difference between AcOEt and H2O becomes large with W/F; this is because the water in the reaction side is selectively removed.Figure optionsDownload high-quality image (117 K)Download as PowerPoint slide