Abstract: Weakly basic anion exchangers of the poly(meth)acrylamide type which have been prepared by aminolysis of poly(meth)acrylonitrile or poly(meth)acrylate with polyamines of defined composition have an improved absorption capacity for sulphate ions and are suitable for selectively removing sulphate ions from aqueous liquids, in particular from sodium chloride brine and from waste waters.

Abstract: Weakly basic anion exchangers of the poly(meth)acrylamide type which have been prepared by aminolysis of poly(meth)acrylonitrile or poly(meth)acrylate with polyamines of defined composition have an improved absorption capacity for sulphate ions and are suitable for selectively removing sulphate ions from aqueous liquids, in particular from sodium chloride brine and from waste waters.

Abstract: The invention relates to a process for preparing anion exchangers based on crosslinked, water-insoluble organic polymers containing aromatic nuclei, in which, in the first step, N-hydroxymethylphthalimide is produced by reaction of phthalimide with aqueous formaldehyde solution in swelling agents in the presence of bases; if desired, this N-hydroxymethylphthalimide is converted in a 2nd step to the bis)phthalimidomethyl)ether or an ester of N-hydroxymethylphthalimide; said polymers are aminomethylated wtih N-hydroxy-methylphthalimide, bis)phthalimidomethyl) ether or an ester of N-hydroxymethylphthalimide in the presence of Friedel-Craft catalysts and swelling agents and the amidomethylated polymers are finally saponified to form the aminomethylated polymers, wherein, in the first reaction step, the base used for producing N-hy-droxymethylphthalimide is sodium hydroxide solution and this sodium hydroxide solution is added in such an amount and at such a rate that the reaction of phthalimide with formaldehyde t

Abstract: Azo dyes are obtained by diazotizing an aromatic amine and combining the resulting diazonium salt solution with a sulpho-containing coupling component when the sole acid donor used for the diazotization reaction--instead of the otherwise customary mineral or fatty acids--is a low molecular weight, nonsurfactantlike aromatic sulphonic acid.

Abstract: A new method of diazotization consists in using as the diazotizing agent in an aqueous, aqueous organic or organic medium the system comprising salt of nitrous acid+acid insoluble in the reaction medium, in particular organic or inorganic cation exchangers having acid groups. The diazonium salt solutions thus prepared are immediately reacted with coupling components to give azo dyestuffs, the insoluble acid and/or its salt being separated off before or after the coupling.

Abstract: Stable, concentrated aqueous solutions of, in particular, anionic reactive dyestuffs are obtained in a comparatively simple manner by freeing from salts, preferably by means of membrane separation processes, solutions of these substances just as they are obtained in the course of synthesis, and by replacing, with the aid of ion exchangers, the cations which cause sparing solubility.