Separating aromatics from non-aromatics by polyimide-polyester membrane
AssigneeExxon Research & Engineering Co.
InventorsWin-Sow Winston Ho, Guido Sartori, Warren A. Thaler, David C. Dalrymple
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Abstract
A copolymer composition comprising the hard segment of a polyimide, the soft segment of an oligomeric aliphatic polyester, and a diepoxide for crosslinking and esterification. The diepoxide polyimide copolymer membranes have exhibited high selectivity and flux for separation of an aromatic/saturate mixture. These membranes have shown much better stability in soaking with an aromatic/saturate feed than the copolymer membranes without a diepoxide.
Claims9
A process for the separation of aromatics from non-aromatics by selectively permeating the aromatics through a thin membrane including a copolymer comprising a diepoxide crosslinked/esterified polyimide-aliphatic polyester copolymer comprising hard polyimide segments having a glass-transition temperature (Tg) higher than 130.degree. C. and soft polyester segments having a Tg lower than that of the hard segments wherein, said copolymer is cross-linked through the carboxylic acid group adjacent to the ester.
Dependencies are inferred from the claim text.