Patent ID: 9266058
Filing Date: 2016-02-23
CPC Classification: B01D,Y02C

Claim Text:
1. A process for separating at least one gas from a mixture of gases using a polyimide membrane comprising a polyimide polymer with hydroxyl and acetoxy functional groups the molar ratio of said hydroxyl functional groups to said acetoxy functional groups is in a range of 1:1 to 8:1, said process comprising: (a) providing said polyimide membrane comprising said polyimide polymer with hydroxyl and acetoxy functional groups which is permeable to said at least one gas; (b) contacting the mixture on one side of the polyimide membrane to cause said at least one gas to permeate the membrane; and (c) removing from the opposite side of the membrane a permeate gas composition comprising a portion of said at least one gas which permeated said polyimide membrane; wherein said polyimide polymer comprises a plurality of repeating units of formula (I), wherein formula (I) is wherein n and m are independent integers from 20 to 500; wherein n:m is in a range of 1:1 to 8:1.