Low-Temperature Fluidity Improver for Biodiesel Fuel

Abstract

Provided is a low-temperature fluidity improver capable of efficiently improving the low-temperature fluidity of a biodiesel fuel. The low-temperature fluidity improver for biodiesel fuels includes a specific aromatic carboxylic acid-based compound.

1 . A low-temperature fluidity improver for biodiesel fuels, comprising:
 (i) a compound represented by the following general formula (1) as a component (A):   
       
         
           
           
               
               
           
         
       
       wherein R 1  and R 3  each represent a hydrogen atom or a hydrocarbon group which may contain one or more atoms selected from sulfur atoms, oxygen atoms and nitrogen atoms, R 2  and R 4  each represent a hydrogen atom, a carboxyl group, or a hydrocarbon group which may contain one or more atoms selected from sulfur atoms, oxygen atoms and nitrogen atoms, and R 2  and R 3  or R 3  and R 4  may be bonded to each other to form a ring, provided that R 2  and R 4  do not simultaneously represent carboxyl groups, and
 a compound represented by the following general formula (2) as a component (B): 
 
       
         
           
           
               
               
           
         
       
       wherein R 5  and R 6  each represent a hydrogen atom or a hydrocarbon group which has 8 to 22 carbon atoms and which may contain oxygen atoms and/or nitrogen atoms, provided that R 5  and R 6  do not simultaneously represent hydrogen atoms; or
 (ii) an amide compound represented by the following general formula (3): 
 
       
         
           
           
               
               
           
         
       
       wherein R 21  and R 23  each represent a hydrogen atom or a hydrocarbon which may contain one or more atoms selected from sulfur atoms, oxygen atoms and nitrogen atoms, R 22  and R 24  each represent a hydrogen atom, a carboxyl group, a hydrocarbon group which may contain one or more atoms selected from sulfur atoms, oxygen atoms and nitrogen atoms, or a group represented by the following general formula (4): 
       
         
           
           
               
               
           
         
       
       wherein R 25  and R 26  each represent a hydrogen atom or a hydrocarbon group which has 8 to 22 carbon atoms and which may contain one or more atoms selected from oxygen atoms and/or nitrogen atoms, provided that R 25  and R 26  do not simultaneously represent hydrogen atoms, and R 27  and R 28  each represent a carboxyl group or a group represented by the general formula (4), provided that R 22  and R 23  or R 23  and R 24  may be bonded to each other to form a ring, and R 22  and R 24  do not simultaneously represent carboxyl groups or groups represented by the general formula (4). 
     
     
         2 . A low-temperature fluidity improver for biodiesel fuels according to  claim 1 , wherein the compound represented by the general formula (1) comprises isophthalic acid or trimellitic acid. 
     
     
         3 . A low-temperature fluidity improver for biodiesel fuels according to  claim 1 , wherein R 5  and R 6  in the compound represented by the general formula (2) each represent a hydrogen atom or a linear alkyl group having 8 to 16 carbon atoms. 
     
     
         4 . A low-temperature fluidity improver for biodiesel fuels according to  claim 1 , wherein, in the compound represented by the general formula (3), R 21 , R 22 , R 23 , and R 24  each represent a hydrogen atom, or R 21  and R 23  each represent a hydrogen atom, and one of R 22  and R 24  represents a hydrogen atom and the other represents a carboxyl group. 
     
     
         5 . A low-temperature fluidity improver for biodiesel fuels according to  claim 1 , wherein R 25  and R 26  in the general formula (4) each represent a hydrogen atom or a linear alkyl group having 8 to 16 carbon atoms. 
     
     
         6 . A low-temperature fluidity improver for biodiesel fuels according to  claim 1 , wherein the amide compound represented by the general formula (3) comprises a compound obtained by a dehydration reaction of
 a compound represented by the following general formula (5):   
       
         
           
           
               
               
           
         
       
       wherein R 21  and R 23  each represent a hydrogen atom or a hydrocarbon group which may contain one or more atoms selected from sulfur atoms, oxygen atoms and nitrogen atoms, R 32  and R 34  each represent a hydrogen atom, a carboxyl group, or a hydrocarbon group which may contain one or more atoms selected from sulfur atoms, oxygen atoms and nitrogen atoms, and R 32  and R 23  or R 23  and R 34  may be bonded to each other to form a ring, provided that R 32  and R 34  do not simultaneously represent carboxyl groups; with
 a compound represented by the following general formula (6): 
 
       
         
           
           
               
               
           
         
       
       wherein R 25  and R 26  each represent a hydrogen atom or a hydrocarbon group which has 8 to 22 carbon atoms and which may contain an oxygen atoms and/or a nitrogen atoms, provided that R 25  and R 26  do not simultaneously represent hydrogen atoms. 
     
     
         7 . A low-temperature fluidity improver for biodiesel fuels according to  claim 6 , wherein, in the compound represented by the general formula (5), R 21 , R 32 , R 23 , and R 34  each represent a hydrogen atom, or R 21  and R 23  each represent a hydrogen atom, and one of R 32  and R 34  represents a hydrogen atom and the other represents a carboxyl group. 
     
     
         8 . A low-temperature fluidity improver for biodiesel fuels according to  claim 6 , wherein R 25  and R 26  in the general formula (6) each represent a hydrogen atom or a linear alkyl group having 8 to 16 carbon atoms. 
     
     
         9 . A biodiesel fuel composition, comprising:
 the low-temperature fluidity improver for a biodiesel fuel according to any one of  claim 1  to  claim 8 ; and   a biodiesel fuel.   
     
     
         10 . A biodiesel fuel composition according to  claim 9 , further comprising a cetane number improver and/or a detergent. 
     
     
         11 . A biodiesel fuel composition according to  claim 9 , further comprising one or more kinds of other additives selected from the group consisting of a solvent, an antioxidant, a metal deactivator, a deicing agent, a corrosion inhibitor, an antistatic agent, a colorant, and a defoaming agent.