Green high-efficiency corrosion inhibitor

Abstract

A corrosion inhibitor for use in aqueous fluids, e.g. brine, which contact a metal surface, contains a blend or cross-linked reaction product of a main chain type polybenzoxazine (MCTPB) and a chitosan component selected from the group consisting of chitosan, chitosan glycol, and combinations thereof. The MCTPB can be made by reacting formaldehyde, bisphenol A, and tetraethylenepentamine (TEPA). The corrosion inhibitor may contain a small amount of an inorganic acid and/or an organic acid. Suitable organic acids include, but are not necessarily limited to organic acid selected from the group of carboxylic acid consisting of formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, citric acid, oxalic acid, malic acid, lactic acid, benzoic acid, or selected from the group of sulfonic acids consisting of p-toluenesulfonic acid, trifluoromethanesulfonic acid, 2-aminoethanesulfonic acid, alkyl-aryl-sulfonic acids such as dodecylbenzenesulfonate, polymeric sulfonic acids, fluorinated derivatives of these organic acids, and combinations thereof.

What is claimed is: 
     
         1 . A corrosion inhibitor for inhibiting or preventing the corrosion of a metal surface in contact with an aqueous fluid, the corrosion inhibitor comprising:
 a blend of main chain type polybenzoxazine (MCTPB) and a chitosan component selected from the group consisting of chitosan, chitosan glycol, and combinations thereof;   a cross-linked reaction product of chitosan and MCTPB; and   combinations thereof.   
     
     
         2 . The corrosion inhibitor of  claim 1  where the weight ratio of chitosan to MCTPB ranges from about 5 to 1 to about 0.5 to 3.5. 
     
     
         3 . The corrosion inhibitor of  claim 1  where the weight ratio of chitosan to MCTPB ranges from about 1.5 to 2.5 to about 0.5 to 1.5. 
     
     
         4 . The corrosion inhibitor of  claim 1  where the corrosion inhibitor contains from about 0.01 wt % to about 1 wt %, based on the total corrosion inhibitor, of an acid selected from the group consisting of:
 an organic acid selected from the group of carboxylic acid consisting of formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, citric acid, oxalic acid, malic acid, lactic acid, benzoic acid, or selected from the group of sulfonic acids consisting of p-toluenesulfonic acid, trifluoromethanesulfonic acid, 2-aminoethanesulfonic acid, alkyl-aryl-sulfonic acids such as dodecylbenzenesulfonate, polymeric sulfonic acids, fluorinated derivatives of these organic acids, and combinations thereof; 
 an inorganic acid selected from the group consisting of hydrochloric acid, sulfuric acid, phosphoric acid, and combinations thereof; and 
 combinations thereof. 
 
     
     
         5 . The corrosion inhibitor of  claim 1  where the MCTPB is made by reacting formaldehyde, bisphenol A, and tetraethylenepentamine (TEPA). 
     
     
         6 . The corrosion inhibitor of  claim 5  where the mole ratio of formaldehyde to bisphenol A to TEPA is about 4:1:1. 
     
     
         7 . A corrosion inhibitor for inhibiting or preventing the corrosion of a metal surface in contact with an aqueous fluid, the corrosion inhibitor comprising:
 a blend of main chain type polybenzoxazine (MCTPB) and a chitosan component selected from the group consisting of chitosan, chitosan glycol, and combinations thereof;   a cross-linked reaction product of chitosan and MCTPB;   from about 0.01 wt % to about 1 wt %, based on the total corrosion inhibitor, of an acid; and   combinations thereof,   
       where the weight ratio of chitosan to MCTPB ranges from about 5 to 1 to about 0.5 to 3.5. 
     
     
         8 . The corrosion inhibitor of  claim 7  where the weight ratio of chitosan to MCTPB ranges from about 1.5 to 2.5 to about 0.5 to 1.5. 
     
     
         9 . The corrosion inhibitor of  claim 7  where the acid is selected from the group consisting of:
 an organic acid selected from the group of carboxylic acid consisting of formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, citric acid, oxalic acid, malic acid, lactic acid, benzoic acid, or selected from the group of sulfonic acids consisting of p-toluenesulfonic acid, trifluoromethanesulfonic acid, 2-aminoethanesulfonic acid, alkyl-aryl-sulfonic acids such as dodecylbenzenesulfonate, polymeric sulfonic acids, fluorinated derivatives of these organic acids, and combinations thereof; 
 an inorganic acid selected from the group consisting of hydrochloric acid, sulfuric acid, phosphoric acid, and combinations thereof; and 
 combinations thereof. 
 
     
     
         10 . The corrosion inhibitor of  claim 7  where the MCTPB is made by reacting formaldehyde, bisphenol A, and tetraethylenepentamine (TEPA). 
     
     
         11 . The corrosion inhibitor of  claim 10  where the mole ratio of formaldehyde to bisphenol A to TEPA is about 4:1:1. 
     
     
         12 . A composition comprising:
 brine; and   corrosion inhibitor for inhibiting or preventing the corrosion of a metal surface in contact with an aqueous fluid, the corrosion inhibitor comprising:
 a blend of main chain type polybenzoxazine (MCTPB) and a chitosan component selected from the group consisting of chitosan, chitosan glycol, and combinations thereof; 
 a cross-linked reaction product of chitosan and MCTPB; and 
 combinations thereof. 
   
     
     
         13 . The composition of  claim 12  where the weight ratio of chitosan to MCTPB in the corrosion inhibitor ranges from about 5 to 1 to about 0.5 to 3.5. 
     
     
         14 . The composition of  claim 12  where the weight ratio of chitosan to MCTPB in the corrosion inhibitor ranges from about 1.5 to 2.5 to about 0.5 to 1.5. 
     
     
         15 . The composition of  claim 12  where the corrosion inhibitor contains from about 0.01 wt % to about 1 wt %, based on the total corrosion inhibitor, of an acid selected from the group consisting of:
 an organic acid selected from the group of carboxylic acid consisting of formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, citric acid, oxalic acid, malic acid, lactic acid, benzoic acid, or selected from the group of sulfonic acids consisting of p-toluenesulfonic acid, trifluoromethanesulfonic acid, 2-aminoethanesulfonic acid, alkyl-aryl-sulfonic acids such as dodecylbenzenesulfonate, polymeric sulfonic acids, fluorinated derivatives of these organic acids, and combinations thereof; 
 an inorganic acid selected from the group consisting of hydrochloric acid, sulfuric acid, phosphoric acid, and combinations thereof; and 
 combinations thereof. 
 
     
     
         16 . The composition of  claim 12  where in the corrosion inhibitor the MCTPB is made by reacting formaldehyde, bisphenol A, and tetraethylenepentamine (TEPA). 
     
     
         17 . The composition of  claim 16  where the mole ratio of formaldehyde to bisphenol A to TEPA is about 4:1:1. 
     
     
         18 . The composition of  claim 12  where the amount of corrosion inhibitor in the brine ranges from about 1 to about 500 ppm. 
     
     
         19 . The composition of  claim 12  where the brine is selected from the group consisting of brine used to recover oil and/or gas from a subterranean formation, brine produced from an oil or gas well, brine used in the processing of oil and/or gas, and combinations thereof.