Triazine carboxylic acids as corrosion inhibitors for aqueous systems

Abstract

Triazine di- and tricarboxylic acids of the formula ##STR1## wherein Z is a straight-chain or branched chain unsubstituted or substituted 1-11C alkylene group, a 2 or 3C alkenylene group, a 5-12C cycloalkylene group or an unsubstituted or substituted arylene group, X is H, an alkali metal, an alkaline earth metal, NH.sub.4.sup.+ or a primary, secondary or tertiary 1-12C ammonium residue, R.sub.1 and R.sub.2 are the same or different and each is H, 1-4C alkyl or a group --Z--COOX or R.sub.1 or R.sub.2 together with Z can form a 5- or 6-membered heterocyclic ring, R.sub.3 is 1-12C alkyl, phenyl or a group of formula --NR.sub.4 R.sub.5, --OR.sub.6 or --SR.sub.6 in which R.sub.4 and R.sub.5, independently, are H, 1-12C alkyl optionally substituted by a hydroxyl group, cyclohexyl, an aryl group having from 6 to 10 ring carbon atoms, optionally substituted or a group --Z--COOX and R.sub.6 is H, 1-12C alkyl, or a 6-12C aryl group, are excellent corrosion inhibitors for aqueous systems in contact with ferrous metals. Such systems may be e.g. water circuits, aqueous machining fluids or any other aqueous functional fluids.