Semi-permeable membranes consisting predominantly of polycarbonates derived from tetrahalobisphenols
US4818254A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 6, 1988 |
| Grant date | Apr 4, 1989 |
| Priority date | — |
| Expiry date | Jan 6, 2008 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01B2210/0046
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
The invention is an improved gas separation membrane comprising a thin, discriminating layer consisting predominantly of a carbonate polymer derived from a bisphenol corresponding to Formula I ##STR1## wherein R at each occurrence is independently H, Cl, Br, or C.sub.1 -C.sub.4 alkyl and R.sup.1 is ##STR2## --S--, --SO.sub.2 --, --O--, or a C.sub.1 -C.sub.6 divalent hydrocarbon or a C.sub.1 -C.sub.6 divalent fluorocarbon radical or inertly substituted hydrocarbon radical, with the proviso that at least 25 weight percent of the moieties derived from the bisphenol of Formula I present in the discriminating layer bear R groups which are exclusively Br or Cl, the gas separation membrane exhibiting a separation factor for oxygen and nitrogen at 24.degree. C. of at least 6.1. In another aspect this invention relates to a process for separating oxygen from nitrogen, or a nitrogen-containing gas.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.