Method and a composition for inhibiting corrosion

Claim 3

A method according to claim 1, characterized in that, the substituent R is a straight or branched aliphatic group having 8 to 18 carbon atoms, R 1 is hydrogen or has the same meaning as R and n is 1 to 5.

Claim 4

A method according to claim 1 or 2, characterized in that, the amino carboxylic acid is used in combination with a quaternary ammonium compound having the general formula ##STR7## wherein at least one of the groups R is an organic hydrophobic group having 6 carbon atoms or more and the other substituents independently are alkyl or hydroxylalkol groups having 1 to 4 carbon atoms, benzyl groups or alkoxy groups of the formula (C 2 H 4 O) p H or (C 3 H 6 O) p H where p is 2 to 10 and X is an anion.

Claim 5

A method according to claim 1 or 2, characterized in that, the amino carboxylic acid is used in combination with an ether amine having the general formula ##STR8## wherein R is an organic hydrophobic group containing at least 6 carbon atoms, a is an integer between 1 and 5, m an integer of 0 or 1, n an integer between 2 and 10, the groups X independent of each other are hydrogen, an alkyl group having 1 to 4 carbon atoms or the group (alkylene-O) y H where y is 1 to 10, p is 0,1 or 2 and q is 0 or 1, whereby however q is 0 when p is 2, and the alkylene group is an ethylene-, propylene- or isopropylene group.

Claim 6

A method according to claim 4, characterized in that, the ether amine is used in the form of a sulfite or a bisulfite.

Claim 9

A composition for preventing corrosion of metals in contact with liquid systems, characterized in that, it comprises an amino carboxylic acid having the general formula ##STR9## wherein R is an organic hydrophobic group having 6 to 22 carbon atoms, R 1 is hydrogen, an alkyl group having 1 to 4 carbon atoms or has the same same meaning as R and n is an integer from 1 to 10, or alkali metal salt thereof, in combination with a nitrogen containing compound selected from the groups (a) mono-, di- or polyamines (b) ether mono-, di- or triamines, (c) quaternary ammonium compounds, whereby the compounds of the groups (a), (b) and (c) contain at least one organic hydrophobic group having 6 carbon atoms or more, or (d) a cyclic nitrogen containing compound being morpholine, cyclohexylamine or imidazonlines, whereby the mole ratio of amino carboxylic acid to the nitrogen containing compound is within the range of from 1:20 to 20:1.

Claim 10

A composition for preventing corrosion of metals in contact with liquid systems, characterized in that, it comprises an amino carboxylic acid having the general formula ##STR9## wherein R is an organic hydrophobic group having 6 to 22 carbon atoms, R 1 is hydrogen, an alkyl group having 1 to 4 carbon atoms or has the same same meaning as R and n is an integer from 1 to 10, or alkali metal salt thereof, in combination with a nitrogen containing compound selected from the groups (a) mono-, di- or polyamines (b) ether mono-, di- or triamines, (c) quaternary ammonium compounds, whereby the compounds of the groups (a), (b) and (c) contain at least one organic hydrophobic group having 6 carbon atoms or more, or (d) a cyclic nitrogen containing compound being morpholine, cyclohexylamine or imidazonlines, whereby the mole ratio of amino carboxylic acid to the nitrogen containing compound is within the range of from 1:20 to 20:1.

Claim 11

A composition according to claim 8, characterized in that, the nitrogen containing compound is a quaternary ammonium compound having the general formula ##STR10## wherein at least one of the groups R is an organic hydrophobic group having 6 carbon atoms or more and the other substituents independently are alkyl or hydroxylalkol groups having 1 to 4 carbon atoms, benzyl groups or alkoxy groups of the formula (C 2 H 4 O) p H or (C 3 H 6 O) p H where p is 2 to 10 and X is an anion.

Claim 12

A composition according to claim 8, characterized in that, the nitrogen containing compound is an ether amine having the general formula ##STR11## wherein R is an organic hydrophobic group containing at least 6 carbon atoms, a is an integer between 1 and 5, m an integer of 0 or 1, n an integer between 2 and 10, the groups X independent of each other are hydrogen, an alkyl group having 1 to 4 carbon atoms or the group (alkylene-O) y H where y is 1 to 10, p is 0,1 or 2 and q is 0 or 1, whereby however q is 0 when p is 2, and the alkylene group is an ethylene-, propylene- or isopropylene group.