Corrosion inhibitors containing amphoteric surfactants

Abstract

The invention relates to the use of compositions containing metal salts of compounds of the formula (1) in which R 1 is C 1 - to C 29 -alkyl, C 2 - to C 29 -alkenyl, C 6 - to C 30 -aryl or C 7 - to C 30 -alkylaryl, and amphoteric surfactants as corrosion inhibitors.

1 . A method for inhibiting corrosion on a metal surface, said method comprising contacting said metal surface with a composition comprising a metal salt of the compound of the formula (1) 
       
         
           
           
               
               
           
         
         in which R 1  is C 1 - to C 29 -alkyl, C 2 - to C 29 -alkenyl, C 6 - to C 30 -aryl or C 7 - to C 30 -akylaryl, and an amphoteric surfactant. 
       
     
     
         2 . The method of  claim 1 , wherein R 1  is an alkyl or alkenyl group having 7 to 17 carbon atoms. 
     
     
         3 . The method of  claim 1 , wherein the metal salt is an alkali metal salt. 
     
     
         4 . The method of  claim 1 , wherein the amphoteric surfactant is selected from the group consisting of a compound of the formulae (2) to (14) 
       
         
           
           
               
               
           
         
       
       in which
 R is C 4 - to C 22 -alkyl, C 4 - to C 22 -alkenyl or C 4 - to C 22 -alkylaryl 
 R1 is C 1 - to C 3 -alkyl, C 1 - to C 3 -hydroxyalkyl 
 R3 is methyl or -A-(OA) n -OH 
 R4 is -A-(OA) n -OH 
 A is a C 2 - to C 4 -alkylene group 
 m is a number from 1 to 4 
 n is a number from 1 to 4 
 x is a number from 0 to 10 
 M is H, an alkali metal, alkaline earth metal, ammonium or alkanolammonium. 
 
     
     
         5 . The method of  claim 1 , wherein a total amount of metal salt to amphoteric surfactant is from 5 to 5000 ppm. 
     
     
         6 . The method of  claim 1 , wherein a weight ratio of metal salt to amphoteric surfactant is from 1:9 to 9:1. 
     
     
         7 . The method of  claim 1 , wherein said composition further comprises a hydrocarbon and said metal surface is an apparatus for conveying and transporting the hydrocarbon. 
     
     
         8 . The method of  claim 1 , wherein the composition further comprises a metal processing composition. 
     
     
         9 . A composition containing at least one metal salt of a compound of the formula (1) 
       
         
           
           
               
               
           
         
       
       in which R 1  is C 1 - to C 29 -alkyl, C 2 - to C 29 -alkenyl, C 6 - to C 30 -aryl or C 7 - to C 30 -alkylaryl, and at least one amphoteric surfactant. 
     
     
         10 . The composition as claimed in  claim 9 , wherein a weight ratio of metal salt to amphoteric surfactant is from 9:1 to 1:9.