Method of inhibiting corrosion

Claim 1

A PROCESS OF REDUCING THE CORROSIVENESS TO A CORRODIBLE FERROUS METAL OF A CORROSIVE FLUID CONTAINING AT LEAST ONE CORROSIVE AGENT FROM THE CLASS CONSISTING OF CARBON DIOXIDE, HYDROGEN SULFIDE, BRINES AND AQUEOUS AND NON-AQUEOUS SOLUTIONS OF CORROSIVE ACIDS WHICH COMPRISES ADDING TO SAID CORROSIVE FLUID AN INHIBITING AMOUNT OF A COMPOUND FROM THE GROUP CONSISTING OF ORGANIC POLYCARBOXY ACID AMIDES AND ORGANIC POLYCARBOXY ACID SALTS OF AN ORGANIC MONOCARBOXY ACID AMIDE OF AN ALIPHATIC POLYAMINE CONTAINING AT LEAST TWO PRIMARY AMINO GROUPS AND AT LEAST ONE SECONDARY AMINO GROUP INTERCONNECTED BY CARBON ATOMS IN A LINEAR CHAIN, AT LEAST ONE OF SAID PRIMARY AND SECONDARY AMINO GROUPS BEING AMIDIFIED BY A CARBOXYL GROUP OF SAID ORGANIC MONOCARBOXY ACID AND AT LEAST ONE OF SAID PRIMARY AND SECONDARY AMINO GROUPS BEING REACTED WITH ONE OF THE CARBOXYL GROUPS OF SAID ORGANIC POLYCARBOXY ACID, SAID COMPOUND CONTAINING BOTH FREE CARBOXYL GROUPS AND BASIC AMINO GROUPS FROM THE CLASS CONSISTING OF PRIMARY AND SECONDARY AMINO GROUPS, THE SAID ORGANIC MONOCARBOXY ACID CONTAINING AT LEAST EIGHT CARBON ATOMS, THE SAID ORGANIC POLYCARBOXY ACID CONTAINING AT LEAST TEN CARBON ATOMS, WITH THE FURTHER PROVISO THAT THE MOLAR RATIO OF THE PRIMARY AND SECONDARY AMINO NITROGEN OF SAID POLYAMINE TO THE CARBOXYL GROUPS IN SAID MONOCARBOXY ACID REACTED THEREWITH IS NOT GREATER THAN 5:1 AND NOT LESS THAN 2:1 AND THE MOLAR RATIO OF THE REMAINING PRIMARY AND SECONDARY AMINO NITROGEN OF SAID POLYAMINE TO THE CARBOXYL GROUPS OF SAID POLYCARBOXY ACID IS NOT GREATER THAN 20:1 AND NOT LESS THAN 2:1.