Additives for lubricating oils and fuel oils, lubricating oil compositions, and fuel oil compositions

Abstract

Additives for lubricating oils and for fuel oils which comprise as the main component a disulfide represented by the following general formula (I) or (IV): R 1 OOC-A 1 -S x -A 2 -COOR 2   (I) (R 1 and R 2 each independently represent a hydrocarbyl group which has 1 to 30 carbon atoms and may have oxygen atom, sulfur atom or nitrogen atom, A 1 and A 2 each independently represent a group represented by CR 3 R 4 , R 3 and R 4 each independently representing hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and x represents 2.) R 1 OOC-A 3 -S x -A 4 -COOR 2   (IV) (R 1 and R 2 are as defined above, A 3 and A 4 each independently represent a group represented by CR 5 R 6 —CR 7 R 8 , R 5 to R 8 each independently representing hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and x represents 2.) The additives exhibit excellent functions as the extreme pressure additive and the antiwear agent and the suppressed corrosive property to nonferrous metals and are advantageously used as the sulfur-based extreme pressure additives for lubricating oils and fuel oils.

1 . An additive for lubricating oils which comprises as a main component a disulfide compound represented by general formula (I):  
       R 1 OOC-A 1 -S x -A 2 -COOR 2   (I)  
     wherein R 1  and R 2  each independently represent a hydrocarbyl group which has 1 to 30 carbon atoms and may have oxygen atom, sulfur atom or nitrogen atom, A 1  and A 2  each independently represent a group represented by CR 3 R 4 , R 3  and R 4  each independently representing hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and x represents 2.  
   
   
       2 . An additive for lubricating oils which comprises as a main component a disulfide compound which is obtained by oxidative coupling of an ester of a mercaptoalkanecarboxylic acid represented by at least one of general formula (II):  
       R 1 OOC-A 1 -SH  (II)  
     wherein R 1  represents a hydrocarbyl group which has 1 to 30 carbon atoms and may have oxygen atom, sulfur atom or nitrogen atom, and A 1  represents a group represented by CR 3 R 4 , R 3  and R 4  each independently representing hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and  
     general formula (III):  
       R 2 OOC-A 2 -SH  (III)  
     wherein R 2  represents a hydrocarbyl group which has 1 to 30 carbon atoms and may have oxygen atom, sulfur atom or nitrogen atom, and A 2  represent a group represented by CR 3 R 4 , R 3  and R 4  each independently representing hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms.  
   
   
       3 . An additive for lubricating oils which comprises as a main component a disulfide compound represented by general formula (IV):  
       R 1 OOC-A 3 -S x -A 4 -COOR 2   (IV)  
     wherein R 1  and R 2  each independently represent a hydrocarbyl group which has 1 to 30 carbon atoms and may have oxygen atom, sulfur atom or nitrogen atom, A 3  and A 4  each independently represent a group represented by CR 5 R 6 —CR 7 R 8 , R 5  to R 8  each independently representing hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and x represents 2.  
   
   
       4 . An additive for lubricating oils which comprises as a main component a disulfide compound which is obtained by oxidative coupling of an ester of a mercaptoalkanecarboxylic acid represented by at least one of general formula (V):  
       R 1 OOC-A 3 -SH  (V)  
     wherein R 1  represents a hydrocarbyl group which has 1 to 30 carbon atoms and may have oxygen atom, sulfur atom or nitrogen atom, and A 3  represents a group represented by CR 5 R 6 —CR 7 R 8 , R 5  to R 8  each independently representing hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and  
     general formula (VI):  
       R 2 OOC-A 4 -SH  (VI)  
     wherein R 2  represents a hydrocarbyl group which has 1 to 30 carbon atoms and may have oxygen atom, sulfur atom or nitrogen atom, and A 4  represents a group represented by CR 5 R 6 —CR 7 R 8 , R 5  to R 8  each independently representing hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms.  
   
   
       5 . An additive for lubricating oils according to  claim 1 , wherein a content of polysulfide compounds represented by general formula (I) in which x represents a number of 3 or greater is 30% by mass or smaller based on a total of an amount of the disulfide compound and amounts of the polysulfide compounds.  
   
   
       6 . An additive for lubricating oils according to  claim 3 , wherein a content of polysulfide compounds represented by general formula (IV) in which x represents a number of 3 or greater is 30% by mass or smaller based on a total of an amount of the disulfide compound and amounts of the polysulfide compounds.  
   
   
       7 . An additive for fuel oils which comprises as a main component a disulfide compound represented by general formula (I):  
       R 1 OOC-A 1 -S x -A 2 -COOR 2   (I)  
     wherein R 1  and R 2  each independently represent a hydrocarbyl group which has 1 to 30 carbon atoms and may have oxygen atom, sulfur atom or nitrogen atom, A 1  and A 2  each independently represent a group represented by CR 3 R 4 , R 3  and R 4  each independently representing hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and x represents 2.  
   
   
       8 . An additive for fuel oils which comprises as a main component a disulfide compound which is obtained by oxidative coupling of an ester of a mercaptoalkanecarboxylic acid represented by at least one of general formula (II):  
       R 1 OOC-A 1 -SH  (II)  
     wherein R 1  represents a hydrocarbyl group which has 1 to 30 carbon atoms and may have oxygen atom, sulfur atom or nitrogen atom, and A 1  represents a group represented by CR 3 R 4 , R 3  and R 4  each independently representing hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and  
     general formula (III):  
       R 2 OOC-A 2 -SH  (III)  
     wherein R 2  represents a hydrocarbyl group which has 1 to 30 carbon atoms and may have oxygen atom, sulfur atom or nitrogen atom, and A 2  represent a group represented by CR 3 R 4 , R 3  and R 4  each independently representing hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms.  
   
   
       9 . An additive for fuel oils which comprises as a main component a disulfide compound represented by general formula (IV):  
       R 1 OOC-A 3 -S x -A 4 -COOR 2   (IV)  
     wherein R 1  and R 2  each independently represent a hydrocarbyl group which has 1 to 30 carbon atoms and may have oxygen atom, sulfur atom or nitrogen atom, A 3  and A 4  each independently represent a group represented by CR 5 R 6 —CR 7 R 8 , R 5  to R 8  each independently representing hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and x represents 2.  
   
   
       10 . An additive for fuel oils which comprises as a main component a disulfide compound which is obtained by oxidative coupling of an ester of a mercaptoalkanecarboxylic acid represented by at least one of general formula (V):  
       R 1 OOC-A 3 -SH  (V)  
     wherein R 1  represents a hydrocarbyl group which has 1 to 30 carbon atoms and may have oxygen atom, sulfur atom or nitrogen atom, and A 3  represents a group represented by CR 5 R 6 —CR 7 R 8 , R 5  to R 8  each independently representing hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and  
     general formula (VI):  
       R 2 OOC-A 4 -SH  (VI)  
     wherein R 2  represents a hydrocarbyl group which has 1 to 30 carbon atoms and may have oxygen atom, sulfur atom or nitrogen atom, and A 4  represents a group represented by CR 5 R 6 —CR 7 R 8 , R 5  to R 8  each independently representing hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms.  
   
   
       11 . An additive for fuel oils according to  claim 7 , wherein a content of polysulfide compounds represented by general formula (I) in which x represents a number of 3 or greater is 30% by mass or smaller based on a total of an amount of the disulfide compound and amounts of the polysulfide compounds.  
   
   
       12 . An additive for fuel oils according to  claim 9 , wherein a content of polysulfide compounds represented by general formula (IV) in which x represents a number of 3 or greater is 30% by mass or smaller based on a total of an amount of the disulfide compound and amounts of the polysulfide compounds.  
   
   
       13 . A lubricating oil composition which comprises a component (A): a base oil for a lubricating oil and a component (B): an additive for lubricating oils described in any one of  claims 1  to  6 .  
   
   
       14 . A lubricating oil composition according to  claim 13 , wherein a content of the component (B) is in a range of 0.01 to 50% by mass.  
   
   
       15 . A fuel oil composition which comprises a component (X): a fuel oil and a component (Y): an additive for fuel oils described in any one of  claims 7  to  12 .  
   
   
       16 . A fuel oil composition according to  claim 15 , wherein a content of the component (Y) is in a range of 0.01 to 1,000 ppm by mass.