Corrosion inhibitor for protecting metallic materials in strongly alkaline medium
View Patent ↗Corrosion inhibitor and method of protecting metallic materials in strongly alkaline medium by means of a corrosion inhibitor, characterized in that it contains an amine containing at least one CH group bound to the nitrogen.
1. A method of protecting metallic materials in chlorate ion containing, sodium hydoxide solutions comprising: reducing the corrosive effects of the chlorate ions contacting the metallic materials by adding a polyamine to the chlorate ion containing, sodium hydroxide solution having a sodium hydroxide concentration of 5 to 95% by weight, and wherein the polyamine is selected from the group consisting of the reaction products of dichloroethane with ammonia and/or amines, or from the group consisting of the reaction products of ethylene oxide with ammonia or amines, or
wherein the polyamine has one of the formulae (II) and (III) below:
H p —N(CH 2 —CH 2 ) q —[NH r —(CH 2 —CH 2 ) s ] n —NH t (II),
NH 2 —CH 2 —CH 2 —CH 2 —[NH r —(CH 2 —CH 2 —CH 2 ) s ] n —NH 2 (III),
where
n is 0 or an integer from 1 to 300,
p, q, s and t are each 1 or 2, and
r is 0 or 1,
where the sum of the substituents on a nitrogen is three or
an anion, additionally present to balance the charge when a nitrogen is bound to 4 substituents, or
wherein the polyamine has the formula (IV) below:
where v is H or an aminoalkyl radical.
2. The method according to claim 1 , wherein the polyamine has one of the formulae (V) and (VI) below:
NH 2 —CH 2 —CH 2 —[NH—CH 2 —CH 2 ] n —NH 2 (V),
NH 2 —CH 2 —CH 2 —CH 2 —[NH—CH 2 —CH 2 —CH 2 ] n —NH 2 (VI),
where n is 0 or an integer from 1 to 300.