Claims
- 1. A method for the treatment of an aqueous system which comprises adding thereto;
- (i) a phosphonocarboxylic acid which contains at least 3 acid groups which are carboxylic and phosphonic acid groups, such that at least one acid group is a carboxylic acid group and at least one acid group is a phosphonic acid group, at least the said 3 acid groups being attached to carbon atoms, or a water-soluble salt thereof,
- (ii) an amino phosphonic acid having the formula:
- H.sub.2 --PO.sub.3 (CH.sub.2).sub.n --N(R.sub.1)(R.sub.2)
- in which R.sub.1 and R.sub.2 independently represent hydrogen, alkyl, of 1 to 4 carbon atoms, --(CH.sub.2).sub.n PO.sub.3 H.sub.2, or --(CH.sub.2).sub.n COOH, and n is 1 or 2, or a water-soluble salt thereof, and
- (iii) an aminophosphonic acid oxide of the formula:
- H.sub.2 --PO.sub.3 (CH.sub.2).sub.n --N(-->O)(R.sub.1)(R.sub.2)
- in which R.sub.1, R.sub.2 and n are as defined above, or a water-soluble salt thereof.
- 2. A method according to claim 1 in which the amino phosphonic acid is amino tris(methylene phosphonic acid).
- 3. A method according to claim 1 in which the amino phosphonic acid oxide is amino tri(methylene phosphonic acid)-N oxide.
- 4. A method according to claim 1 in which the phosphonic carboxylic acid possesses the general formula: ##STR3## wherein R is hydrogen, alkyl, alkenyl or alkynyl having up to 4 carbon atoms; phenyl; cycloalkyl having 3 to 6 carbon atoms: benzyl; phenethyl or ##STR4## wherein R' is hydrogen, alkyl having 1 to 4 carbon atoms or carboxyl, R" is hydrogen or methyl and R'" is carboxyl or phosphonate.
- 5. A method according to claim 4 in which the phosphonocarboxylic acid is 2-phosphonobutane-1,2,4-tricarboxylic acid.
- 6. A method according to claim 1 in which components (i) and (ii) and (iii) are present in an amount from 0.1 to 50 ppm.
- 7. A method according to claim 6 in which components (i) and (ii) and (iii) are present in an amount from 1 to 12 ppm.
- 8. A method according to claim 1 in which the aqueous system is a cooling water system.
- 9. A method according to claim 1 in which the aqueous system is a hard water system.
- 10. A method according to claim 1 in which at least one of a scale inhibiting polymer, dispersant or azole is also added to the system.
- 11. A method according to claim 10 in which the scale inhibiting polymer is a polyacrylic or polymethacrylic acid having a molecular weight from 1,000 to 5,000 um.
- 12. A method according to claim 10 in which the dispersant is a copolymer of acrylic or methacrylic acid and 2-methyl-2-acrylamido-propane sulphonic acid or a copolymer of maleic acid and allyl sulphonic or styrene sulphonic acid.
- 13. A method according to claim 10 in which the azole is benzotriazole, tolyltriazole or mercaptobenzotriazole.
- 14. A method according to claim 10 in which the scale inhibiting polymer or the dispersant is present in an amount from 1 to 10 ppm.
- 15. A method according to claim 14 in which the scale inhibiting polymer or dispersant is present in an amount from 1 to 5 ppm.
- 16. A method according to claim 10 in which the azole is present in an amount from 1 to 10 ppm.
- 17. A method according to claim 16 in which the azole is present in an amount from 1 to 3 ppm.
Priority Claims (1)
Number |
Date |
Country |
Kind |
8829612 |
Dec 1988 |
GBX |
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Parent Case Info
This is a division of application Ser. No. 454,101, filed Dec. 20, 1989 now U.S. Pat. No. 5,049,304.
US Referenced Citations (10)
Divisions (1)
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Number |
Date |
Country |
Parent |
454101 |
Dec 1989 |
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