Closed loop cooling water corrosion inhibition employing polymaleates and non-borate buffers

Patent metadata

Field	Value
Publication number	US-12546014-B2
Application number	US-202117308719-A
Country	US
Kind code	B2
Filing date	May 5, 2021
Priority date	May 28, 2020
Publication date	Feb 10, 2026
Grant date	Feb 10, 2026

Abstract

A method of inhibiting corrosion of a metal surface in contact with an aqueous medium is provided. The method may include contacting the metal surface with a corrosion inhibitor composition where the corrosion inhibitor composition may include a compound or salt thereof of formula (I). The disclosed corrosion inhibitor composition is especially useful for inhibiting corrosion in closed loop systems.

First claim

What is claimed is:

1 . A method of inhibiting corrosion of a metal surface in contact with an aqueous medium, comprising:
contacting the metal surface in a closed loop system with a corrosion inhibitor composition, wherein the corrosion inhibitor composition comprises an azole and a compound of formula (I), or a salt thereof,

wherein
L is a single bond or a double bond;
R 1 is

n is an integer from 1 to 100; m is an integer from 1 to 100; p is an integer from 2 to 20;
R 3 is —OH, —OCH 3 , an aryl group, or a C 1 -C 4 alkyl;
R 2 is hydrogen, —OH, —OCH 3 , an aryl group, or a C 1 -C 4 alkyl;
provided that when R 1 is

 then L is a double bond; and
adding the corrosion inhibitor composition to the aqueous medium, wherein the compound of formula (I) has a concentration of about 100 ppm to about 5,000 ppm in the aqueous medium, and the azole has a concentration of about 20 ppm to about 500 ppm in the aqueous medium, and wherein the corrosion inhibitor composition has a ratio of 5:1 to about 10:1 of the compound of formula (I) to the azole;
wherein the azole is selected from the group consisting of tolytriazole (TT), benzotriazole (BZT), mercaptobenzothiazole (MBT), butyl benzotriazole (BBT), halogen resistant azole (HRA), a benzimidazole, and any combination thereof; and
wherein the corrosion inhibitor composition does not comprise zinc and phosphorus.

2 . The method of claim 1 , wherein R 1 is

3 . The method of claim 1 , wherein R 1 is

 L is a double bond; and R 2 is hydrogen.

4 . The method of claim 1 , wherein R 1 is

 and R 2 is —OH.

5 . The method of claim 1 , wherein the corrosion inhibitor composition further comprises a silicate.

Assignees

• Ecolab Usa Inc

Inventors

• Chen Bingzhi
• Weberski Jr Michael Patrick
• Yin Zhangzhang

Classifications

• C23F11/124

  Carboxylic acids · CPC title

• C23F11/173 Primary

  Macromolecular compounds · CPC title

• C23F11/181

  Nitrogen containing compounds · CPC title

• C02F2303/08

  Corrosion inhibition · CPC title

• C23F11/182

  Sulfur, boron or silicon containing compounds · CPC title