PROCESS FOR SEPARATING LIQUID MIXTURE.

摘要

This improved process for removing water from a liq mixt is specified to be pervaporation using a copolyimide diaphragm. The structural material of the diaphragm is a copolyimide having repeat units of general formula (I) in which 10-30 mol% of the repeat units have Ia as R and 90 to 70 mol% of the repeat units have Ib and/or Ic as R. In the other specified copolyamidoimide 90 to 10 mol% of the repeat units have structure (II) and 10 to 90 mol% of the repeat units have structure (III). This copolyimide diaphragm is specified to be anti-symmetric. It should be heat-treated at250 deg C or higher (most prefd 280-500 deg C). The copolyimide diaphragm is specified to contain 1 wt% or more with it at 25 deg C for 24 hrs. The liq mixt can be a mixt of organic cpds contg oxygen, of organic cpds contg nitrogen, of inorganic cpds such as inorganic acids, or mixts of these.