Initial study of heterogeneous catalysts behaviour and carrier gas permeation with catalytic inorganic ceramic membrane for lactic acid esterification applications.

Inorganic membranes continue to attract a lot of attention in various fields including industry and academia, due to the great potential they have shown in various applications. Recently, some studies have focused on the water -permeable metallic membrane reactor involving liquid-phase reversible reactions including esterification reactions. Among the membranes considered, inorganic membrane have been found to be the perfect membrane for the esterification reaction process because they can allow heterogeneous catalysts to be deposited easily on the surface of the membrane; this results in increase in the yield of products. The use of inorganic ceramic to selectively eliminate water from the reaction product during esterification of lactic acid is yet another important application that has attracted a lot of attention. In this work, the initial study of heterogeneous catalyst behaviour and carrier gas permeation with inorganic ceramic membrane for lactic acid esterification applications was carried out. Dowex 50W8x, Amberlyst 36, Amberlyst 15 and Amberlyst 16 cation-exchange resins were used as heterogeneous catalysts. The SEM/EDXA of the resin catalyst was investigated in order to determine the surface morphology of the resin. The EDXA of the catalysts showed the presence of sulphur which confirms the sulfonic acid group in the structure of the polymeric compound. The permeation properties of inorganic ceramic membrane with the carrier gases were also analysed between the gauge pressures of 0.01-1.00 bar at the temperature of 60oC (333 K). The membrane was coated twice using silica solution before the permeation experiments. The carrier gas permeance of the silica membrane showed a linear dependence on the inverse square root of the gas molecular weight indicating Knudsen mechanism of transport. Gases with highest viscosity value exhibited the least permeance indicating viscous flow contribution. It was concluded that Knudsen and viscous mechanisms plays a major role in the carrier gas permeation with inorganic ceramic membrane