Stability and pervaporation characteristics of PVA and its blend with PVAm membranes in a ternary feed mixture containing highly reactive epichlorohydrin

Abstract

In order to find an alternative for classical distillation in the recovery of ECH/IPA from azeotropic ECH/IPA/water (50/30/20 w/w, %) mixtures, a pervaporation process has been applied.

Ultra-dehydration of a reactive epichlorohydrin-containing organic mixture using a defect-free thin carbon molecular sieve composite membrane

“…This is attributed to the stronger polar property of ECH, which allows stronger interactions with the hydrophilic membrane. 7 However, ECH flux was not detected in the CMS membrane carbonized at temperatures higher than 700 1C. It is believed that the penetration of ECH (which has the largest molecule size) is restricted by the ultra-micropores of the CMS membrane (a dominant pore size of o3.64 Å, as shown in Fig.…”

“…[23][24][25][26] Recently, for the dehydration of water/IPA/ ECH mixtures, Chaudhari et al studied the stability and separation efficiency of PVA/PVAm (polyvinyl amine) blended membranes. 7 This membrane was stable for up to 15 days in the reactive ECH-containing mixture solution, but it was relatively less stable than a crosslinked PVA membrane. Furthermore, they modified the surface of PVA/TEOS (tetraethyl orthosilicate) membranes with PVAm/STA (silicotungstic acid).…”

“…For the separation of ECH-containing mixtures using a polymeric membrane, the stability of the membrane is one of the main problems to be solved. 7,27 Moreover, polymeric membranes undergo swelling, which can cause reduction of the separation factor. In contrast, such problems did not occur with the CMS membrane due to its high chemical and thermal stability and rigid pores.…”

“…This causes a gradual reduction in the reaction efficiency and eventually demands disposal because the composition becomes inadequate for reuse. 7 Therefore, if water (high heat capacity) is preferentially removed through a membrane process, and the IPA/ECH components are separated and purified through a distillation process, the energy efficiency of the epoxy-resin manufacturing process can be improved by reusing unreacted materials. In addition, it is possible to implement an environment-friendly epoxy-resin production process by preventing the emission of ECH, which is an environmentally harmful material.…”

Hydrophilic and organophilic pervaporation of industrially important α,β and α,ω-diols

“…Therefore, membranes prepared with PVA must be post crosslinked using agents such as glutaraldehyde at relatively low temperatures. 26,27 Because the molecular size of water is much less than that of 1,2-HDO and because of the hydrophilic nature of PVA, it is likely to have a higher affinity (via hydrogen bonds and dipole-dipole interactions) for water than 1,2-HDO.…”