Oligo- or polyamines as oxidation stabilizers for biofuel oils

Abstract

The use of oligo- or polyamines which have a number-average molecular weight of from 46 to 70 000 and are free of phenolic hydroxyl groups for increasing the oxidation stability of biofuel oils based on fatty acid esters, or of mixtures of such biofuel oils with middle distillates of fossil origin and/or of vegetable and/or animal origin, which are essentially hydrocarbon mixtures and are free of fatty acid esters.

1 - 8 . (canceled) 
     
     
         9 . A method for inhibiting oxidation of a biofuel oil comprising
 (A) from 0.1 to 75% by weight of at least one biofuel oil which is based on fatty acid esters, and   (B) from 25 to 99.9% by weight of middle distillates of fossil origin, of vegetable origin, of animal origin, or a combination thereof, which are essentially hydrocarbon mixtures and are free of fatty acid esters,   
       said method, comprising: mixing the biofuel oil with at least one of an oligoamine and a polyamine that has a number-average molecular weight of from 46 to 70 000, is free of phenolic hydroxyl groups and is represented by formula I 
       
         
           
           
               
               
           
         
         in which 
         each R 1  to R 6  radical is independently a hydrogen, a C 1 - to C 30 -alkyl group, a C 5 - to C 8 -cycloalkyl group, a C 1 - to C 29 -alkylcarbonyl group or a C 2 - to C 8 -cyanoalkyl group, where the R 1  and R 2  radicals, the R 5  and R 6  radicals, or the R 1 , R 2 , R 5  and R 6  radicals may in each case also, together with the nitrogen atom which bears them, form a five- or six-membered, saturated or unsaturated ring which may also have further hetero atoms and bear additional substituents, or in each case also together be a methylidene moiety which may be substituted by at least one of a C 1 - to C 30 -alkyl group and a C 6 - to C 12 -aryl group, 
         each A 1  to A 3  is independently a C 1 - to C 12 -alkylene group, where at least one of the R 1  and R 5  radicals may in each case also, together with the nitrogen atom which bears them and a carbon atom of an alkylene group A 1  or A 3 , form a five- or six-membered, saturated or unsaturated ring which may also have further hetero atoms and/or carbonyl carbon atoms and bear additional substituents, and 
         the variables n and m are each integers from 0 to 30, said oligoamine or polyamine operable for increasing the oxidation stability of biofuel oils based on fatty acid esters, or of mixtures of such biofuel oils with middle distillates of fossil origin and/or of vegetable and/or animal origin, which are essentially hydrocarbon mixtures and are free of fatty acid esters. 
       
     
     
         10 . The method according to  claim 9 , which has as R 1  to R 6  radicals, at least one hydrocarbyl radical having from 1 to 30 carbon atoms. 
     
     
         11 . The method according to  claim 10 , in which
 each R 1  to R 6  radical is independently a hydrogen, a C 1 - to C 22 -alkyl group, a C 5 - or C 6 -cycloalkyl group, or a C 1 - to C 21 -alkylcarbonyl group,   each A 1  to A 3  is independently a C 2 - or C 3 -alkylene group, and   the variables n and m are each 0 or 1,   with the proviso that at least one of the R 1  to R 6  radicals is a C 5 - to C 30 -alkyl group, a C 5 - or C 6 -cycloalkyl group or a C 4 - to C 29 -alkylcarbonyl group.   
     
     
         12 . The method according to  claim 11 , in which all R 1  to R 6  radicals are hydrogen. 
     
     
         13 . The method according to  claim 9 , wherein the at least one of an oligoamine and a polyamine is present in the biofuel oil in an amount of from 10 to 10 000 ppm by weight based on the amount of the biofuel oil. 
     
     
         14 . A mixture comprising biofuel oils which are based on fatty acid esters in a weight ratio of from 1:100 000 to 1:100 and at least two oligoamines or polyamines represented by formula I 
       
         
           
           
               
               
           
         
         in which 
         each R 1  to R 6  radical is independently a hydrogen, a C 1 - to C 30 -alkyl group, a C 5 - to C 8 -cycloalkyl group, a C 1 - to C 29 -alkylcarbonyl group or a C 2 - to C 8 -cyanoalkyl group, where the R 1  and R 2  radicals, the R 5  and R 6  radicals, or the R 1 , R 2 , R 5  and R 6  radicals may in each case also, together with the nitrogen atom which bears them, form a five- or six-membered, saturated or unsaturated ring which may also have further hetero atoms and bear additional substituents, or in each case also together be a methylidene moiety which may be substituted by at least one of a C 1 - to C 30 -alkyl group and a C 6 - to C 12 -aryl group, 
         each A 1  to A 3  is independently a C 1 - to C 12 -alkylene group, where at least one of the R 1  and R 5  radicals may in each case also, together with the nitrogen atom which bears them and a carbon atom of an alkylene group A 1  or A 3 , form a five- or six-membered, saturated or unsaturated ring which may also have further hetero atoms and/or carbonyl carbon atoms and bear additional substituents, and 
         the variables n and m are each integers from 0 to 30. 
       
     
     
         15 . A fuel comprising a major proportion of a fuel oil which comprises:
 (C) from 0.1 to 75% by weight of at least one biofuel oil which is based on fatty acid esters, and   (D) from 25 to 99.9% by weight of middle distillates of fossil origin, of vegetable origin, of animal origin, or a combination thereof, which are essentially hydrocarbon mixtures and are free of fatty acid esters,   
       and a minor proportion of at least one of an oligoamine and a polyamine that has a number-average molecular weight of from 46 to 70 000, is free of phenolic hydroxyl groups and is represented by formula I 
       
         
           
           
               
               
           
         
         in which 
         each R 1  to R 6  radical is independently a hydrogen, a C 1 - to C 30 -alkyl group, a C 5 - to C 8 -cycloalkyl group, a C 1 - to C 29 -alkylcarbonyl group or a C 2 - to C 8 -cyanoalkyl group, where the R 1  and R 2  radicals, the R 5  and R 6  radicals, or the R 1 , R 2 , R 5  and R 6  radicals may in each case also, together with the nitrogen atom which bears them, form a five- or six-membered, saturated or unsaturated ring which may also have further hetero atoms and bear additional substituents, or in each case also together be a methylidene moiety which may be substituted by at least one of a C 1 - to C 30 -alkyl group and a C 6 - to C 12 -aryl group, 
         each A 1  to A 3  is independently a C 1 - to C 12 -alkylene group, where at least one of the R 1  and R 5  radicals may in each case also, together with the nitrogen atom which bears them and a carbon atom of an alkylene group A 1  or A 3 , form a five- or six-membered, saturated or unsaturated ring which may also have further hetero atoms and/or carbonyl carbon atoms and bear additional substituents, and 
         the variables n and m are each integers from 0 to 30. 
       
     
     
         16 . A fuel comprising a major proportion of a fuel oil which consists of:
 (E) from 0.1 to 75% by weight of at least one biofuel oil which is based on fatty acid esters, and   (F) from 25 to 99.9% by weight of middle distillates of fossil origin, of vegetable  origin, of animal origin, or a combination thereof, which are essentially hydrocarbon mixtures and are free of fatty acid esters,   
       and a minor proportion of at least one of an oligoamine and a polyamine that has a number-average molecular weight of from 46 to 70 000, is free of phenolic hydroxyl groups and is represented by formula I 
       
         
           
           
               
               
           
         
         in which 
         each R 1  to R 6  radical is independently a hydrogen, a C 1 - to C 30 -alkyl group, a C 5 - to C 8 -cycloalkyl group, a C 1 - to C 29 -alkylcarbonyl group or a C 2 - to C 8 -cyanoalkyl group, where the R 1  and R 2  radicals, the R 5  and R 6  radicals, or the R 1 , R 2 , R 5  and R 6  radicals may in each case also, together with the nitrogen atom which bears them, form a five- or six-membered, saturated or unsaturated ring which may also have further hetero atoms and bear additional substituents, or in each case also together be a methylidene moiety which may be substituted by at least one of a C 1 - to C 30 -alkyl group and a C 6 - to C 12 -aryl group, 
         each A 1  to A 3  is independently a C 1 - to C 12 -alkylene group, where at least one of the R 1  and R 5  radicals may in each case also, together with the nitrogen atom which bears them and a carbon atom of an alkylene group A 1  or A 3 , form a five- or six-membered, saturated or unsaturated ring which may also have further hetero atoms and/or carbonyl carbon atoms and bear additional substituents, and 
         the variables n and m are each integers from 0 to 30. 
       
     
     
         17 . The method according to  claim 9 , further comprising
 passing an air stream through the biofuel oil; and   measuring an induction time to determine the stability of the biofuel oil.   
     
     
         18 . The method according to  claim 17 , wherein the induction time is greater than 7 hours. 
     
     
         19 . The method according to  claim 17 , wherein the induction time is greater than 8 hours. 
     
     
         20 . The method according to  claim 17 , wherein the induction time is greater than 10 hours. 
     
     
         21 . The method according to  claim 17 , wherein the induction time is from 10.1 to 18.7 hours. 
     
     
         22 . The method according to  claim 17 , wherein the induction time is greater than 24 hours.