Wasserbehandlungsverfahren zur Verhinderung von Erdkalisalzniederschlagsbildung

摘要

Chelating polymers are made which comprise wholly aliphatic polymer chains containing no lateral aromatic groups having a molecular weight of 1,000 to 1,000,000 and carrying a number of chelating ligand groups of the formula in which n is 0 or an integer from 1 to 5, R is -(CH2)mCOOH, R1 is -(CH2)mCOOH or H, m being an integer from 1 to 4 and p is 1 to 3, each ligand group being bonded to a carbon atom of the valency chain by a link comprising a valency bond or a divalent group comprising one or more methylene, carbonyl or thiocarbonyl groups. Such polymers may be made by the polymerization of vinyl ethylenediaminetrimethylacetate, N - allyl, N1 - hydroxyethyl-diethylenetriaminetrimethyl acetate, the methacrylamide of ethylenediaminetrimethylacetate, N-allylethylenediaminetetramethylacetate quaternary ammonium iodide, iminodipropionitrile acrylamide, N - methacrylamide - nitrilodiacetic acid methyl ester, N-vinyltriethylenetetraminetetraacetic acid methyl ester, the monoallylamide of nitrilotriacetic acid dimethyl ester, N,N - dihydroxyethylglycineallylamide, vinyl thiourea, vinyl dithiooxamide and N-vinyltriethylenetetraminephosphonic acid methyl ester. The required polymers may also be made by carboxymethylating polyacrylamide and polyallylamine and by other aftertreatments of polymers. The examples describe making chelating polymers by (1) carboxymethylating polyacrylamide by treating it with formaldehyde and sodium cyanide; (2) reacting polyacrylyl chloride with iminodiacetonitrile; (3) carboxymethylating polyallylamine by treating it with formaldehyde and sodium cyanide; (4) polymerizing the acrylic ester of hydroxyethylenediamine triacetic acid; and (5) by treating polyallylamine with acrylonitrile under alkaline conditions.ALSO:Sequestering agents for metals in water comprise aliphatic polymers containing ligand groups which are in their simplest form -NH(CH2)COOH Exemplified are polymers of vinyl ethylenediaminetrimethylacetate N - allyl N - hydroxyethyldiethylenetriaminetrimethylacetate the methacrylamide of ethylenediaminetrimethylacetate, N-allylethylene diaminetetramethylacetate quaternary ammonium iodide, iminodipropionitrile acrylamide, N-methylacrylamidenitrilodiaceti acid methyl ester, N-vinyltriethylene tetraminetetracetic acid methyl ester, the monoallylamide of nitrilotriacetic acid dimethyl ester, N,N-dihydroxy ethylglycineallylamide vinylthiourea, vinyl dithiooxamide and N - vinyltriethylenetetramine phosphonic acid methyl ester or by carboxymethylating polyacrylamide and polyallylamine.