Nitrogen-containing compounds as corrosion inhibitors

Abstract

The present invention relates to nitrogen-containing hydroxyethyl substituted compounds to be used as corrosion inhibitors for metal surfaces, for example in aqueous systems and in particular in oil-field applications, e.g. in oil or gas wells, and which could be used under sweet-well conditions as well as under sour-well conditions. It may also be used in oil-field acidizing and fracture-acidizing well stimulation treatment. The compounds belong to the group of partly ethoxylated fatty alkylamines, partly ethoxylated alkyletheramines and partly or fully hydroxyethyl substituted alkylamdopropylamines. The corrosion inhibitors have the formula (I) where R is a hydrocarbyl or an acyl group having 14-24 carbon atoms, or the group R′OCH 2 CH 2 CH 2 where R′ is a hydrocarbyl group with 14-24 carbon atoms; X is hydrogen, C 2 H 4 OH or the group Y is hydrogen or C 2 H 4 OH and n is 0-3, with the proviso that at least one of the symbols X and Y is C 2 H 4 OH, at most one of the symbols X is n is at least one when R is an acyl group, and when R is a hydrocarbyl group or the group R′OCH 2 CH 2 CH 2 at least one of the symbols X and Y is hydrogen.

1 . A corrosion inhibitor for metal surfaces in an aqueous environment in oil-field applications which comprises at least one hydroxyethyl substituted amine having the formula  
       
         
           
           
               
               
           
         
       
       where R is a hydrocarbyl or an acyl group having 14-24 carbon atoms, or the group R′OCH 2 CH 2 CH 2  where R′ is a hydrocarbyl group with 14-24 carbon atoms; X is hydrogen, C 2 H 4 OH or the group  
       
         
           
           
               
               
           
         
       
       Y is hydrogen or C 2 H 4 OH and n is 0-3, with the proviso that at least one of the symbols X and Y is C 2 H 4 OH, at most one of the symbols X is  
       
         
           
           
               
               
           
         
       
       n is at least one when R is an acyl group, and when R is a hydrocarbyl group or the group R′OCH 2 CH 2 CH 2  at least one of the symbols X and Y is hydrogen.  
     
     
         2 . The corrosion inhibitor of  claim 1 , where R is a hydrocarbyl group having 16-22 carbon atoms.  
     
     
         3 . The corrosion inhibitor of  claim 1 , where n is 0-2.  
     
     
         4 . The corrosion inhibitor of  claim 1 , where n is 1-2.  
     
     
         5 . The corrosion inhibitor of  claim 1 , where R is the group R′OCH 2 CH 2 CH 2 , where R′ has the same meaning as in  claim 1 .  
     
     
         6 . The corrosion inhibitor of  claim 1 , where R is an acyl group with 14-24 carbon atoms and at least one of the symbols X and Y is hydrogen.  
     
     
         7 . The corrosion inhibitor of  claim 1  wherein said amine is of the formula 
         R″(C═O)NHCH 2 CH 2 CH 2 NHCH 2 CH 2 OH  (VI) 
       where R″(C═O) is an acyl group with 14-24 carbon atoms.  
     
     
         8 . The corrosion inhibitor of  claim 1  wherein said aqueous environment is acidic.  
     
     
         9 . The corrosion inhibitor of  claim 1  wherein said oilfield application is under sweet-well conditions.  
     
     
         10 . The corrosion inhibitor of  claim 1  wherein said oilfield application is under sour-well conditions.  
     
     
         11 . The corrosion inhibitor of  claim 1  which comprises a mixture of ethoxylated amines, wherein the said mixture contains a total of 10-50% of primary amino groups, 10-70% of secondary amino groups and 10-50% of tertiary amino groups.  
     
     
         12 . The corrosion inhibitor of  claim 11 , wherein the said mixture contains a total of 10-40% of primary amino groups, 25-65% of secondary amino groups and 20-40% of tertiary amino groups.  
     
     
         13 . The corrosion inhibitor of  claim 12 , wherein the said mixture contains a total of 10-35% of primary amino groups, 30-60% of secondary amino groups and 25-35% of tertiary amino groups.  
     
     
         14 . A method for the inhibition of corrosion on ferrous metal surfaces in an aqueous environment, wherein said method comprises adding to said environment and/or contacting said ferrous metal surface with a corrosion inhibiting effective amount of at least one hydroxyethyl substituted amine having the formula  
       
         
           
           
               
               
           
         
       
       where R is a hydrocarbyl or an acyl group having 14-24 carbon atoms, or the group R′OCH 2 CH 2 CH 2  where R′ is a hydrocarbyl group with 14-24 carbon atoms; X is hydrogen, C 2 H 4 OH or the group  
       
         
           
           
               
               
           
         
       
       Y is hydrogen or C 2 H 4 OH and n is 0-3, with the proviso that at least one of the symbols X and Y is C 2 H 4 OH, at most one of the symbols X is  
       
         
           
           
               
               
           
         
       
       n is at least one when R is an acyl group, and when R is a hydrocarbyl group or the group R′OCH 2 CH 2 CH 2  at least one of the symbols X and Y is hydrogen.  
     
     
         15 . The method of  claim 14 , where R is a hydrocarbyl group having 16-22 carbon atoms.  
     
     
         16 . The method of  claim 14 , where n is 0-2.  
     
     
         17 . The method of  claim 16 , where n is 1-2.  
     
     
         18 . The method of  claim 14 , where R is the group R′OCH 2 CH 2 CH 2 , where R has the same meaning as in  claim 14 .  
     
     
         19 . The method of  claim 14 , where R is an acyl group with 14-24 carbon atoms and at least one of the symbols X and Y is hydrogen.  
     
     
         20 . The method of  claim 1  wherein said amine is of the formula 
         R″(C═O)NHCH 2 CH 2 CH 2 NHCH 2 CH 2 OH  (VI) 
       where R″(C═O) is an acyl group with 14-24 carbon atoms.