Patent ID: 8496831

Claim:
A process for separating water from organic compounds comprising: (a) providing a composite membrane having a feed side and a permeate side, the composite membrane comprising: (i) a microporous support layer; (ii) a first dense selective layer of a hydrophilic polymer; and (iii) a second dense selective layer of a dioxole-based polymer having the structure wherein R 1 and R 2 are fluorine or CF 3 R 3 is fluorine or —O—CF 3 , and x and y represent the relative proportions of the dioxole and the tetrafluoroethylene blocks, such that x+y=1; the first dense selective layer being positioned between the microporous support layer and the second dense selective layer; (b) passing a feed solution comprising at least 10 wt % water and an organic compound across the feed side; (c) withdrawing from the feed side a dehydrated solution having a lower water content than that of the feed solution; (d) withdrawing from the permeate side a permeate vapor having a higher water content than that of the feed solution, wherein the composite membrane provides a water permeance of at least about 500 gpu when in operation in the process.