Lubricating oil compositions having functionalized quercetin antioxidants

Abstract

This disclosure provides a method for improving or maintaining antioxidant performance of a lubricating oil in an engine or other mechanical component lubricated with the lubricating oil by using as the lubricating oil a formulated oil. The formulated oil has a composition including a lubricating oil base stock as a major component, and at least one functionalized quercetin antioxidant, as a minor component. The at least one functionalized quercetin antioxidant is soluble in the lubricating oil. Antioxidant performance is improved or maintained as compared to antioxidant performance achieved using a lubricating oil containing a phenolic or aminic antioxidant, as determined by Lubricant Oxidation Test as described herein or Catalytic Oxidation Test as described herein. This disclosure also relates to lubricating oils having at least one functionalized quercetin antioxidant. The lubricating oils are useful as passenger vehicle engine oils (PVEO), commercial vehicle engine oils (CVEO), and other mechanical industrial applications.

1 . A lubricating oil having a composition comprising a lubricating oil base stock as a major component, and at least one functionalized quercetin antioxidant, as a minor component; wherein the functionalized quercetin antioxidant has the following structural formula: 
       
         
           
           
               
               
           
         
         wherein each R is independently hydrogen, alkyl group, sulfur or oxygen containing alkyl group, alkylated acyl group, or sulfur or oxygen containing alkylated acyl group, with the proviso that at least two R groups are hydrogen and at least one R group is other than hydrogen. 
       
     
     
         2 . The lubricating oil of  claim 1  wherein the at least one functionalized quercetin antioxidant is soluble in the lubricating oil; and wherein, in an engine or other mechanical component lubricated with the lubricating oil, antioxidant performance is improved or maintained as compared to antioxidant performance achieved using a lubricating oil containing a phenolic or aminic antioxidant, as determined by Lubricant Oxidation Test or Catalytic Oxidation Test. 
     
     
         3 . The lubricating oil of  claim 1  wherein the functionalized quercetin antioxidant comprises a partially esterified quercetin or a partially etherified quercetin. 
     
     
         4 . The lubricating oil of  claim 1  wherein the functionalized quercetin antioxidant comprises the reaction product of quercetin with a carboxylic acid. 
     
     
         5 . The lubricating oil of  claim 1  wherein the functionalized quercetin antioxidant comprises the reaction product of quercetin with 2-hexyldecanoic acid, wherein the molar ratio of quercetin:2-hexyldecanoic acid is 1:2 or 1:3. 
     
     
         6 . The lubricating oil of  claim 1  wherein the functionalized quercetin antioxidant comprises the reaction product of quercetin with mPAO S-propionic acid. 
     
     
         7 . The lubricating oil of  claim 1  wherein the functionalized quercetin antioxidant comprises the reaction product of quercetin with brominated atactic polypropylene (aPP). 
     
     
         8 . The lubricating oil of  claim 1  wherein the functionalized quercetin antioxidant is selected from the group having the formula 
       
         
           
           
               
               
           
         
       
     
     
         9 . The lubricating oil of  claim 1  wherein the lubricating oil base stock comprises a Group I, Group II, Group III, Group IV or Group V base oil. 
     
     
         10 . The lubricating oil of  claim 1  wherein the functionalized quercetin antioxidant is present in an amount from 0.01 to 5 weight percent, based on the total weight of the formulated oil. 
     
     
         11 . The lubricating oil of  claim 1  wherein the lubricating oil base stock is present in an amount of from 50 weight percent to 95 weight percent, based on the total weight of the formulated oil. 
     
     
         12 . The lubricating oil of  claim 1  further comprising one or more aminic antioxidants. 
     
     
         13 . The lubricating oil of  claim 1  further comprising one or more of an antiwear additive, viscosity modifier, detergent, dispersant, pour point depressant, metal deactivator, seal compatibility additive, inhibitor, and anti-rust additive. 
     
     
         14 . A method for improving or maintaining antioxidant performance of a lubricating oil in an engine or other mechanical component lubricated with lubricating oil by using as the lubricating oil a formulated oil, said formulated oil having a composition comprising a lubricating oil base stock as a major component, and at least one functionalized quercetin antioxidant, as a minor component; wherein the functionalized quercetin antioxidant has the following structural formula: 
       
         
           
           
               
               
           
         
         wherein each R is independently hydrogen, alkyl group, sulfur or oxygen containing alkyl group, alkylated acyl group, or sulfur or oxygen containing alkylated acyl group, with the proviso that at least two R groups are hydrogen and at least one R group is other than hydrogen. 
       
     
     
         15 . The method of  claim 14  wherein the at least one functionalized quercetin antioxidant is soluble in the lubricating oil; and wherein antioxidant performance is improved or maintained as compared to antioxidant performance achieved using a lubricating oil containing a phenolic or aminic antioxidant, as determined by Lubricant Oxidation Test or Catalytic Oxidation Test. 
     
     
         16 . The method of  claim 14  wherein the functionalized quercetin antioxidant comprises partially esterified quercetin or a partially etherified quercetin. 
     
     
         17 . The method of  claim 14  wherein the functionalized quercetin antioxidant comprises the reaction product of quercetin with a carboxylic acid. 
     
     
         18 . The method of  claim 14  wherein the functionalized quercetin antioxidant comprises the reaction product of quercetin with 2-hexyldecanoic acid, wherein the molar ratio of quercetin:2-hexyldecanoic acid is 1:2 or 1:3. 
     
     
         19 . The method of  claim 14  wherein the functionalized quercetin antioxidant comprises the reaction product of quercetin with mPAO S-propionic acid. 
     
     
         20 . The method of  claim 14  wherein the functionalized quercetin antioxidant comprises the reaction product of quercetin with brominated atactic polypropylene (aPP). 
     
     
         21 . The method of  claim 14  wherein the functionalized quercetin antioxidant is selected from the group having the formula 
       
         
           
           
               
               
           
         
       
     
     
         22 . The method of  claim 14  wherein the lubricating oil base stock comprises a Group I, Group II, Group III, Group IV or Group V base oil. 
     
     
         23 . The method of  claim 14  wherein the functionalized quercetin antioxidant is present in an amount from 0.01 to 5 weight percent, based on the total weight of the lubricating oil. 
     
     
         24 . The method of  claim 14  wherein the lubricating oil base stock is present in an amount of from 50 weight percent to 95 weight percent, based on the total weight of the lubricating oil. 
     
     
         25 . The method of  claim 14  wherein the lubricating oil further comprises one or more aminic antioxidants. 
     
     
         26 . The method of  claim 14  wherein the lubricating oil further comprises one or more of an antiwear additive, viscosity modifier, detergent, dispersant, pour point depressant, metal deactivator, seal compatibility additive, inhibitor, and anti-rust additive. 
     
     
         27 . The method of  claim 14  wherein the lubricating oil is a passenger vehicle engine oil (PVEO) or a commercial vehicle engine oil (CVEO). 
     
     
         28 . A composition comprising functionalized quercetin. 
     
     
         29 . The composition of  claim 28  wherein the functionalized quercetin has the following structural formula: 
       
         
           
           
               
               
           
         
         wherein each R is independently hydrogen, alkyl group, sulfur or oxygen containing alkyl group, alkylated acyl group, or sulfur or oxygen containing alkylated acyl group, with the proviso that at least two R groups are hydrogen and at least one R group is other than hydrogen. 
       
     
     
         30 . The composition of  claim 28  which comprises partially esterified quercetin or a partially etherified quercetin. 
     
     
         31 . The composition of  claim 28  which comprises the reaction product of quercetin with a carboxylic acid. 
     
     
         32 . The composition of  claim 28  which comprises the reaction product of quercetin with 2-hexyldecanoic acid, wherein the molar ratio of quercetin:2-hexyldecanoic acid is 1:2 or 1:3. 
     
     
         33 . The composition of  claim 28  which comprises the reaction product of quercetin with mPAO S-propionic acid. 
     
     
         34 . The composition of  claim 28  wherein the functionalized quercetin comprises the reaction product of quercetin with brominated atactic polypropylene (aPP). 
     
     
         35 . The composition of  claim 28  which is selected from the group having the formula 
       
         
           
           
               
               
           
         
       
     
     
         36 . The composition of  claim 28  which is an antioxidant. 
     
     
         37 . The composition of  claim 36  further comprising one or more aminic antioxidants. 
     
     
         38 . The composition of  claim 36  which is soluble in a lubricating oil. 
     
     
         39 . A process for preparing functionalized quercetin, said process comprising esterifying or etherifying quercetin under reaction conditions sufficient to prepare the functionalized quercetin. 
     
     
         40 . The process of  claim 39  wherein the functionalized quercetin has the following structural formula: 
       
         
           
           
               
               
           
         
         wherein each R is independently hydrogen, alkyl group, sulfur or oxygen containing alkyl group, alkylated acyl group, or sulfur or oxygen containing alkylated acyl group, with the proviso that at least two R groups are hydrogen and at least one R group is other than hydrogen. 
       
     
     
         41 . The process of  claim 39  wherein the functionalized quercetin comprises partially esterified quercetin or a partially etherified quercetin. 
     
     
         42 . The process of  claim 39  wherein the functionalized quercetin comprises the reaction product of quercetin with a carboxylic acid. 
     
     
         43 . The process of  claim 39  wherein the functionalized quercetin comprises the reaction product of quercetin with 2-hexyldecanoic acid, wherein the molar ratio of quercetin:2-hexyldecanoic acid is 1:2 or 1:3. 
     
     
         44 . The process of  claim 39  wherein the functionalized quercetin comprises the reaction product of quercetin with mPAO S-propionic acid. 
     
     
         45 . The process of  claim 39  wherein the functionalized quercetin comprises the reaction product of quercetin with brominated atactic polypropylene (aPP). 
     
     
         46 . The process of  claim 39  wherein the functionalized quercetin is selected from the group having the formula 
       
         
           
           
               
               
           
         
       
     
     
         47 . The process of  claim 39  wherein the functionalized quercetin is an antioxidant. 
     
     
         48 . The process of  claim 39  wherein the functionalized quercetin is soluble in a lubricating oil.