Process for inhibiting corrosion

Claim 1

The process of claim 1 wherein the amount of inhibitor utilized is from about 10 to 6,000 p.p.m. and wherein said acidic liquid medium is an aqueous strong mineral acid or a strong organic acid.

Claim 6

A method for preventing corrosion of metals in contact with an aqueous acidic liquid medium, which method comprises maintaining in said acidic medium a corrosion-preventing amount of a corrosion inhibitor consisting essentially of the product poduced in a two stage reaction, both stages of which are conducted in the liquid phase and under neutral conditions, the first stage of which consists of mixing together at temperatures within the range of about 10*C to 70* C an aqueous formaldehyde pentamethylenediamine and pentamethylenediameine or hexamethylenediamine so as to form a solid condensation product, and the second stage of which consists of reacting at temperatures within the range of 75* C to 200* C said solid condensation product with cyclohexanone until dissolution of said solid condensation product occurs, followed by separation of the reaction product of said second stage from the reaction mixture to obtain said material suitable for use as a corrosion inhibitor.

Claim 7

A method for preventing corrosion of metals in contact with an aqueous acidic liquid medium comprising maintaining in said acidic liquid medium a corrosion-preventing amount of a corrosion inhibitor consisting essentially of the reaction product formed by reacting in the liquid phase under neutral conditions: a. at least one carbonyl compound of one to 10 carbon atoms having a single carbonyl group as the only functional group, containing no hetero atoms and free of ethylenic or acetylenic unsaturation, and b. At least one amine selected from the group consisting of b1 acylic alkylene diamines of five to 15 carbon atoms having only two primary amino groups which are separated by a chain of five to 10 carbon atoms and b2 cyclic amines of six to 15 carbon atoms which have only two primary amino groups, are free of ethylenic and acetylenic unsaturation, and have no functional groups other than said two primary amino groups, wherein said corrosion inhibitor is formed by reacting said amine and formaldehyde in an initial reaction at a temperature within the range of from about 10* C to 70* C so as to form a solid condensation product followed by further reacting in a second stage liquid phase reaction said solid condensation product with additional of said carbonyl compound, said second stage reaction being conducted at a temperature of at least 75* C. and being conducted for a period of time sufficient to cause dissolution of said solid condensation product.