Appeal No. 1998-1175
Application No. 08/374,462
contacting the mixture with a multilayer composite membrane
comprising a first polymeric support layer and an active
separating layer comprising a blend of a water soluble polymer
and one-half equivalent or more of an acid gas reactive salt
wherein the membrane separates the acid gas from the gaseous
mixture by selectively permeating the acid gas. Further
details of this appealed subject matter are set forth in
representative independent claim 1 which reads as follows:
1. A process for separating acid gas from a gaseous
mixture containing acid gas and at least one non-acid gas, the
process comprising contacting the gaseous mixture with a
multilayer composite membrane comprising a first polymeric
support layer and an active separating layer comprising a
blend of a water soluble polymer and one-half equivalent or
more of an acid gas reactive salt based upon the repeating
unit of the water soluble polymer, the acid gas reactive salt
which is represented by the formula A B • nH O wherein A is ax y 2
monovalent cation and B is a monovalent anion wherein x and y
are integers such that the salt remains charge neutral, n
represents the number of moles of bound water per mole of
salt, and the pKa of the conjugate acid of the monovalent
anion is greater than 3, wherein the multilayer composite
membrane separates the acid gas from the gaseous mixture by
selectively permeating the acid gas.
The references relied upon by the examiner as evidence of
obviousness are:
Quinn et al. (Quinn ‘114) 4,780,114 Oct. 25, 1988
Van Wijk et al. (Van Wijk) 4,913,818 Apr. 3, 1990
Quinn et al. (Quinn ‘456) 4,973,456 Nov. 27, 1990
Quinn et al. (Quinn ‘298) 5,336,298 Aug. 9, 1994
2
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