Triazine carboxylic acids as corrosion inhibitors for aqueous systems

Claim 1

A method of inhibiting the corrosion of a ferrous metal in contact with an aqueous system which comprises incorporating in the aqueous system an effective corrosion inhibiting amount of a compound having the formula: ##STR5## wherein Z is a straight- or branched chain 1-11C alkylene group, a 2-3C alkenylene group, a 5-12C cycloalkylene group or an arylene group, having 6-10 ring carbon atoms, the said aliphatic or cycloaliphatic groups Z being optionally substituted by one or more OH, SH or 1-4C carboxyalkyl groups and/or interrupted by one or more O or S atoms or ##STR6## or >N--R' groups, wherein R' is H, 1-4C alkyl or 1-4C carboxyalkyl, and said aromatic groups Z being optionally substituted by one or more 1-4C alkyl groups, OH, 1-4C alkoxy groups, SH, 1-4C alkylthio, carboxylic or sulphonic acid groups; X is H, an alkali metal, an alkaline earth metal, NH 4 + , or a 1-12C primary-, secondary- or tertiary ammonium residue optionally substituted with one or more OH groups; R 1 and R 2 are the same or different and each is H, 1-4C alkyl or a group --Z--COOX wherein Z and X have their previous significance or when Z is alkylene, or alkenylene, R 1 or R 2 , with Z and the nitrogen atom to which they are attached, can form a 5- or 6-membered heterocyclic ring; R 3 is 1-12C alkyl, phenyl or a group of formula --NR 4 R 5 , --OR 6 , or --SR 6 in which R.sub. 4 and R 5 , independently, are H, 1-12C alkyl optionally substituted by an OH group, a cyclohexyl group, an aryl group having from 6 to 10 carbon atoms, optionally substituted by one or more 1-4C alkyl groups, OH, 1-4C alkoxy, thio, 1-4C alkylthio, carboxylic or sulphonic acid groups, a group --Z--COOX wherein Z and X have their previous significance or R 4 , R 5 and the N atom to which they are attached can form a 5-7 membered heterocyclic ring optionally interrupted by other hetero atoms and R 6 is H, 1-12C alkyl group or an aryl group having from 6 to 10 ring carbon atoms.

Claim 2

A method of inhibiting the corrosion of a ferrous metal in contact with an aqueous system which comprises incorporating in the aqueous system an effective corrosion inhibiting amount of a compound having the formula: ##STR5## wherein Z is a straight- or branched chain 1-11C alkylene group, a 2-3C alkenylene group, a 5-12C cycloalkylene group or an arylene group, having 6-10 ring carbon atoms, the said aliphatic or cycloaliphatic groups Z being optionally substituted by one or more OH, SH or 1-4C carboxyalkyl groups and/or interrupted by one or more O or S atoms or ##STR6## or >N--R' groups, wherein R' is H, 1-4C alkyl or 1-4C carboxyalkyl, and said aromatic groups Z being optionally substituted by one or more 1-4C alkyl groups, OH, 1-4C alkoxy groups, SH, 1-4C alkylthio, carboxylic or sulphonic acid groups; X is H, an alkali metal, an alkaline earth metal, NH 4 + , or a 1-12C primary-, secondary- or tertiary ammonium residue optionally substituted with one or more OH groups; R 1 and R 2 are the same or different and each is H, 1-4C alkyl or a group --Z--COOX wherein Z and X have their previous significance or when Z is alkylene, or alkenylene, R 1 or R 2 , with Z and the nitrogen atom to which they are attached, can form a 5- or 6-membered heterocyclic ring; R 3 is 1-12C alkyl, phenyl or a group of formula --NR 4 R 5 , --OR 6 , or --SR 6 in which R.sub. 4 and R 5 , independently, are H, 1-12C alkyl optionally substituted by an OH group, a cyclohexyl group, an aryl group having from 6 to 10 carbon atoms, optionally substituted by one or more 1-4C alkyl groups, OH, 1-4C alkoxy, thio, 1-4C alkylthio, carboxylic or sulphonic acid groups, a group --Z--COOX wherein Z and X have their previous significance or R 4 , R 5 and the N atom to which they are attached can form a 5-7 membered heterocyclic ring optionally interrupted by other hetero atoms and R 6 is H, 1-12C alkyl group or an aryl group having from 6 to 10 ring carbon atoms.