Production, Characterization and Use of Sulfonated Polystyrene and Polysulfone Membranes as Catalysts in the Esterification Reaction of Oleic Acid

Abstract

Biodiesel is a renewable and non-toxic biofuel that can be produced by the esterification reaction. In this reaction, acid catalysts are used and, due to the numerous advantages, heterogeneous catalysts are gaining space. Polysulfone (PSF) and sulfonated polystyrene (PSS) membranes were prepared to catalyze the esterification reaction of oleic acid with methanol, producing biodiesel. Several morphological types of membranes were obtained: dense, porous and electrospun. The reaction conditions were: temperature of 100 °C, molar ratio of 10:1 (methanol:oleic acid), 5% catalyst and time of 2 hours. By means of the BET and BJH methods it was possible to obtain the surface area of the membranes, volume and pore size. The consumption of oleic acid and the formation of the ester were confirmed by the analyzes of CGMS and the FTIR bands, respectively. For the membranes that presented the PSS, 2 hours of reaction were enough for almost total consumption of oleic acid, except for the dense membrane.

Incorporation of graphene oxide and reduced graphene oxide on the performance of hybrid polysulfone membranes for gas permeation

“…Lima et al [27] reported a similar behavior for PSU membranes. According to the authors, up to 132 °C there was a loss of water that was physically adsorbed on the membranes; from 132 °C to approx.…”

“…Close to 100 °C, there was a small loss of mass probably related to the evaporated water that was physically adsorbed on the surface of the membranes. The first considerable mass loss (T ≈ 170 °C) may have been the result of thermolysis of the bonds of the sulfonic groups, which occur in this temperature range [27]. The second mass loss occurred at approx.…”

“…According to the authors, up to 132 °C there was a loss of water that was physically adsorbed on the membranes; from 132 °C to approx. 230 °C, there was the loss of mass attributed to the breaking of the bonds involving the sulfonic groups, and, at approximately 500 °C, the degradation of the main polymer chain began [27][28][29].…”