US 4,784,774 AGranted

Compositions containing phosphonoalkane carboxylic acid for scale inhibition

AssigneeThe B. F. Goodrich Company

InventorsZahid Amjad, William F. Masler, III

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Abstract

An antiscalant admixture is disclosed of a homopolymer of maleic acid or a copolymer and a phosphonoalkane carboxylic acid for reducing scaling in an aqueous system wherein the weight ratio of said copolymer to said phosphonic acid is 5:1 to 1:5, wherein molecular weight of said copolymer is 2,000 to 20,000, and wherein said polymer is composed of at least two of the comonomers selected from monounsaturated monocarboxylic and dicarboxylic acids of 3 to 5 carbon atoms, water-soluble salts thereof, and alkyl esters thereof of 1 to 6 carbon atoms in said alkyl groups; substituted acrylamides; acrylamidoalkane sulfonic acids and water-soluble salts thereof; vinyl sulfonic acid and water-soluble salts thereof; hydroxyalkyl acrylates with 2 to 4 carbons in the alkylene group; styrene sulfonic acids and water-soluble salts thereof; allyloxyhydroxyalkane sulfonic acids and water-soluble salts; vinyl carboxylates; polymerized vinyl alcohols and water-soluble salts thereof; and mixtures of such comonomers.

Claims16

Dependent claims

An admixture useful for inhibiting formation of scale-forming salts in an aqueous medium comprising at least one copolymer having weight average molecular weight of 1,000 to 50,000 and at least one phosphonoalkane carboxylic acid or a water-soluble salt thereof;

wherein weight ratio of said copolymer to said phosphonoalkane carboxylic acid or its salt is 10:1 to 1:10;
wherein said phosphonoalkane carboxylic acid and salts thereof contain 1 to 2 phosphono groups and 2 to 6 carbon atoms in the alkane group;
wherein said copolymer consists essentially of at least one polymerized carboxyl monomer in amount of 50 to 90% by weight and at least one polymerized comonomer in amount of at least 5% by weight;
wherein said carboxyl monomer is selected from acrylic acid, methacrylic acid, itaconic acid, maleic acid or its anhydride, salts of such acids, and mixtures thereof, and wherein said comonomer is selected from alkyl esters, substituted acrylamides, alkoxyalkyl acrylates, vinyl alcohol, and mixtures of such comonomers;
wherein said alkyl esters are alkyl esters of itaconic acid and maleic acid containing 1 to 6 carbon atoms in each alkyl group;
wherein repeating units of said substituted acrylamides are defined as follows:
##STR17## where R is hydrogen or methyl and R.sup.1 and R.sup.2 are individually selected from hydrogen and alkyl groups of 1 to 12 carbon atoms provided that at least R.sup.1 or R.sup.2 is other than hydrogen;
wherein repeating units of said alkoxyalkyl acrylates are defined as follows:
##STR18## where R is hydrogen or methyl, R.sup.1 is an alkylene group of 2 to 4 carbon atoms, R.sup.2 is an alkyl group of 1 to 10 carbon atoms, and n is an integer of 1 to 5;
and wherein repeating units of said vinyl alcohols are defined as follows:
##STR19## where R is hydrogen or an alkyl group of 1 to 6 carbon atoms.

8 more elements

Method for inhibiting precipitation of scale-forming salts, including calcium sulfate, in an aqueous medium comprising the step of adding to said aqueous medium an effective amount of at least one copolymer and at least one phosphonoalkane carboxylic acid or a water-soluble salt thereof;

wherein weight ratio of said copolymer to said phosphonoalkane carobyxlic acid or its salt is 10:1 to 1:10;
wherein said phosphonoalkane carboxylic acid and salts thereof contain 1 to 2 phosphono groups and 2 to 6 carbon atoms in the alkane group;
wherein said copolymer is a copolymer consisting essentially of at least one polymerized carboxyl monomer in amount of 50 to 90% by weight and at least one polymerized comonomer in amount of least 5% by weight;
wherein said carboxyl monomer selected from acrylic acid, methacrylic acid, itaconic acid, maleic acid or its anhydride, salts of such acids, and mixtures thereof, and wherein said comonomer is selected from alkyl esters, substituted acrylamides, alkoxyalkyl acrylates, vinyl alcohol, and mixtures of such comonomers;
wherein said alkyl esters are alkyl esters of itaconic acid and maleic acid containing 1 to 6 carbon atoms in each alkyl group;
wherein repeating units of said substituted acrylamides are defined as follows:
##STR20## where R is hydrogen or methyl and R.sup.1 and R.sup.2 are individually selected from hydrogen and alkyl groups of 1 to 12 carbon atoms provided that at least R.sup.1 or R.sup.2 is other than hydrogen;
wherein repeating units of said alkoxyalkyl acrylates are defined as follows:
##STR21## where R is hydrogen or methyl, R.sup.1 is an alkylene group of 2 to 4 carbon atoms, R.sup.2 is an alkyl group of 1 to 10 carbon atoms, and n is an integer of 1 to 5;
and wherein repeating units of said vinyl alcohols are defined as follows:
##STR22## where R is hydrogen or an alkyl group of 1 to 6 carbon atoms.

8 more elements

Dependencies are inferred from the claim text.