Abstract: A semipermeable membrane is described which comprises a homogeneously miscible polymer blend of an aromatic polyamide and polyvinylpyrrolidone. The aromatic polyamide is in particular formed of recurrent units of the formula I: ##STR1## wherein E.sup.1 and E.sup.2 are identical or different and are selected from the groupings ##STR2## --AR.sup.1 --, and --AR.sup.1 --X--AR.sup.2,where AR.sup.1 and Ar.sup.2 are the same or different 1,2-phenylene, 1,3-phenylene or 1,4-phenylene groups which may be substituted by (C.sub.1 -C.sub.6)-alkyl, (C.sub.1 -C.sub.6)-alkoxy, --CF.sub.3 or halogen and X denotesa) a direct bond or one of the following divalent groups: --O--, --C(CF.sub.3).sub.2 --, --SO.sub.2 --, --C(R.sup.1).sub.2 --, with R.sup.1 being hydrogen, (C.sub.1 -C.sub.6)-alkyl or fluoroalkyl having from 1 to 4 carbon atoms in the alkyl group or--Z--AR.sup.1 --Z--, where Z is one of the groups --O-- and --C(CH.sub.3).sub.2 or--O--Ar.sup.1 --Y--Ar.sup.2 --O--, where Y has the meaning given under Xa) above.

Abstract: A process for the preparation of 4-halo-3-oxo-2-alkoxyiminobutyric esters.A process for the preparation of 4-halo-3-oxo-2-alkoxyiminobutyric esters by solvent-free halogenation of the liquid substrate of a 3-oxo-2-alkoxyaiminobutyric ester with elemental halogen.

Abstract: A macrophorous, asymmetric, hydrophilic membrane containing polyaramid is described. The characterizing features are that it contains a copolyamide which has at least the following recurring structural units:(A) --OC--Ar--CO--(B) --NH--Ar'--NH(C) ##STR1## (D) ##STR2## where Ar and Ar' denote divalent aromatic radicals in which the valence bonds ar in the para or comparable coaxial or parallel position,denotes a lower alkyl radical or a lower alkoxy radical, in each case having up to 4 carbon atoms, or a halogen radical, and denotes an unsubstituted or substituted methylene radical or an --O--Ar--O-- group where Ar has the same structure as given above.