Imino alkylimino phosphonates and method for preparing and using same

Claim 2

A nitrilo tris[ethylimino bis(methyl phosphonic acid)] compound having the general formula ##EQU6## wherein M is selected from the group consisting of hydrogen, alkali metal ions, ammonium ions, alkylammonium ions and mixtures of hydrogen and at least one other of said ions.

Claim 3

The compound of claim 1 wherein each M is sodium.

Claim 4

The compound of claim 1 wherein each M is an alkali metal ion.

Claim 5

The compound of claim 1 wherein each M is an ammonium ion.

Claim 6

The compound of claim 1 wherein each M is an alkylammonium ion.

Claim 7

Nitrilo tris[ethylimino bis(methyl phosphonic acid)].

Claim 8

Nitrilo tris[ethylimino bis(methyl phosphonic acid)].

Claim 9

Octasodium nitrilo tris[ethylimino bis(methyl phosphonate)].

Claim 10

Octasodium nitrilo tris[ethylimino bis(methyl phosphonate)].

Claim 11

Octaammonium nitrilo tris[ethylimino bis(methyl phosphonate)].

Claim 12

Octaammonium nitrilo tris[ethylimino bis(methyl phosphonate)].

Claim 13

A process for preparing a nitrilo tris[ethylimino bis(methyl phosphonic acid)] which comprises forming an aqueous mixture having a pH below about 4 and containing (1) a phosphorus source selected from the group consisting of (a) orthophosphorous acid and (b) a combination of PCl 3 and H 2 O, (2) formaldehyde and (3) nitrilotriethyleneamine in a molar ratio of (1) to (2) to (3) of about 6:6:1, and subjecting said mixture to temperatures above about 70°C. whereby said nitrilo tris[ethylimino bis(methyl phosphonic acid)] having multiple N--C--P linkages is formed.

Claim 14

A process for preparing a nitrilo tris[ethylimino bis(methyl phosphonic acid)] which comprises forming an aqueous mixture having a pH below about 4 and containing (1) a phosphorus source selected from the group consisting of (a) orthophosphorous acid and (b) a combination of PCl 3 and H 2 O, (2) formaldehyde and (3) nitrilotriethyleneamine in a molar ratio of (1) to (2) to (3) of about 6:6:1, and subjecting said mixture to temperatures above about 70°C. whereby said nitrilo tris[ethylimino bis(methyl phosphonic acid)] having multiple N--C--P linkages is formed.

Claim 15

The process of claim 9 wherein said mixture additionally contains about 0.01 weight percent to about 10 weight percent of halide ions in order to inhibit the oxidation of said orthophosphorous acid to orthophosphoric acid during said process.

Claim 16

A process for preparing nitrilo tris[ethylimino bis(methyl phosphonic acid)] which process comprises forming an aqueous mixture of nitrilotriethyleneamine and orthophosphorous acid in a molar ratio of said amine to said acid of about 1:6, and at least about 0.5 weight percent of halide ions, the pH of said mixture being below about 4, and blending into said mixture over a period of from about 10 minutes to about 3 hours while said mixture is at a temperature above about 85°C. at least under 6 molar equivalents of formaldehyde, based on the amount of said amine in said mixture, whereby said nitrilo tris[ethylimino bis(methyl phosphonic acid)] is produced.

Claim 17

A process for preparing nitrilo tris[ethylimino bis(methyl phosphonic acid)] which process comprises forming an aqueous mixture of nitrilotriethyleneamine and orthophosphorous acid in a molar ratio of said amine to said acid of about 1:6, and at least about 0.5 weight percent of halide ions, the pH of said mixture being below about 4, and blending into said mixture over a period of from about 10 minutes to about 3 hours while said mixture is at a temperature above about 85°C. at least under 6 molar equivalents of formaldehyde, based on the amount of said amine in said mixture, whereby said nitrilo tris[ethylimino bis(methyl phosphonic acid)] is produced.

Claim 20

The method of claim 12 wherein the scale-forming salt is an alkaline earth metal carbonate, sulfate or oxalate.

Claim 21

The method of claim 12 wherein the mole ratio of precipitation inhibitor to scale-forming salts is from about 1:1.5 to about 1:10,000.

Claim 22

The method of claim 14 wherein the precipitation inhibitor is present in the system at concentrations from about 0.1 to about 500 parts per million.

Claim 23

The method of claim 12 wherein each M is sodium.

Claim 24

The method of claim 12 wherein each M is an alkali metal ion.

Claim 25

The method of claim 12 wherein each M is an ammonium ion.

Claim 26

The method of claim 12 wherein said compound is nitrilo tris[ethylimino bis(methyl phosphonic acid)].

Claim 29

The method of claim 20 wherein each M is sodium.

Claim 30

The method of claim 20 wherein each M is an alkali metal ion.

Claim 31

The method of claim 20 wherein each M is an ammonium ion.

Claim 32

The method of claim 20 wherein the water of said system additionally contains a water-soluble compound of hexavalent chromium.

Claim 33

The method of claim 20 wherein the water of said system additionally contains a zinc compound soluble in water in the presence of said phosphonic acid compound.

Claim 34

The method of claim 20 wherein the water of said system additionally contains from about 0.05 to 5 ppm of a compound selected from the group consisting of 1,2,3-triazoles, thiols of thiazoles, thiols of oxazoles, thiols of imidazoles and mixtures thereof.

Claim 35

The method of claim 26 wherein the water of said system additionally contains a zinc compound soluble in water in the presence of said phosphonic acid compound, sufficient to supply to said water from about 2 to 100 ppm of zinc ions.

Claim 36

The method of claim 20 wherein the said compound is nitrilo tris[ethylimino bis(methyl phosphonic acid)].

Claim 37

A composition useful in inhibiting the corrosion of metals in a water system consisting essentially of from about 20 percent to about 90 percent by weight of a nitrilo tris[ethylimino bis(methyl phosphonic acid)] compound having the general formula ##EQU9## wherein M is selected from the group consisting of hydrogen, alkali metal ions, ammonium ions, alkylammonium ions and mixtures of hydrogen and at least one other of such ions, and from about 10 percent to about 80 percent of a zinc compound soluble in water in the presence of said phosphonic acid compound.

Claim 38

A composition useful in inhibiting the corrosion of metals in a water system consisting essentially of from about 20 percent to about 90 percent by weight of a nitrilo tris[ethylimino bis(methyl phosphonic acid)] compound having the general formula ##EQU9## wherein M is selected from the group consisting of hydrogen, alkali metal ions, ammonium ions, alkylammonium ions and mixtures of hydrogen and at least one other of such ions, and from about 10 percent to about 80 percent of a zinc compound soluble in water in the presence of said phosphonic acid compound.

Claim 39

A composition useful in inhibiting the corrosion of metals in a water system consisting essentially of (1) from about 20 percent to about 90 percent by weight of a nitrilo tris[ethylimino bis(methyl phosphonic acid)] compound having the general formula ##EQU10## wherein M is selected from the group consisting of hydrogen, alkali metal ions, ammonium ions and mixtures of hydrogen and at least one other of such ions, (2) from about 1 percent to about 10 percent by weight of a compound selected from the group consisting of 1,2,3-triazoles, thiols of thiazoles, thiols of oxazoles, thiols of imidazoles and mixtures thereof, and (3) up to about 79 percent by weight of a zinc compound soluble in water in the presence of said phosphonic acid compound.

Claim 40

A composition useful in inhibiting the corrosion of metals in a water system consisting essentially of (1) from about 20 percent to about 90 percent by weight of a nitrilo tris[ethylimino bis(methyl phosphonic acid)] compound having the general formula ##EQU10## wherein M is selected from the group consisting of hydrogen, alkali metal ions, ammonium ions and mixtures of hydrogen and at least one other of such ions, (2) from about 1 percent to about 10 percent by weight of a compound selected from the group consisting of 1,2,3-triazoles, thiols of thiazoles, thiols of oxazoles, thiols of imidazoles and mixtures thereof, and (3) up to about 79 percent by weight of a zinc compound soluble in water in the presence of said phosphonic acid compound.