Synthesis of biolubricant esters from unsaturated fatty acid derivatives

Abstract

The present invention is generally directed to diester-based lubricant compositions comprising one or more isomeric mixtures of diester species. The present invention is also directed to methods of making these and other similar lubricant compositions. In some embodiments, the methods for making such diester-based lubricants utilize a biomass precursor material from which mono-unsaturated free lipid species can be provided or otherwise generated, wherein such mono-unsaturated free lipid species arc converted to isomeric diol species en route to the synthesis of diester species for use as/in the diester-based lubricant compositions.

1 . A lubricant composition comprising at least one isomeric mixture of diester species comprising the following isomerically-related diester structures: 
       
         
           
           
               
               
           
         
       
       wherein R 1  and R 2  are the same or independently selected from C 1  to C 20  hydrocarbon groups, and wherein n and m are the same or independently selected from the group of integers 2 to 20. 
     
     
         2 . The lubricant composition of  claim 1 , wherein the kinematic viscosity of the composition at a temperature of 100° C. is at least 3 mm 2 /s. 
     
     
         3 . The lubricant composition of  claim 1 , said composition having a pour point of less than −20° C. 
     
     
         4 . The lubricant composition of  claim 1 , wherein R 1  is selected to have a carbon number from at least about 1 to at most about 15. 
     
     
         5 . The lubricant composition of  claim 1 , wherein R 2  is selected to have a carbon number from at least about 1 to at most about 15. 
     
     
         6 . The lubricant composition of  claim 1 , comprising at least two different isomeric mixtures of diester species. 
     
     
         7 . The lubricant composition of  claim 1 , wherein n and m are independently selected from the group of integers 5 to 10. 
     
     
         8 . The lubricant composition of  claim 1 , wherein said composition comprises quantities of at least two different isomeric mixtures of diester species. 
     
     
         9 . The lubricant composition of  claim 1 , wherein the isomeric diester species, of which the at least one isomeric mixture is comprised, have a molecular mass that is from at least about 400 a.m.u. to at most about 1100 a.m.u. 
     
     
         10 . The lubricant composition of  claim 1 , wherein the at least one isomeric mixture of diester species is selected from the group of isomeric diester pairs consisting of octadecane-1,9-diyl dihexanoate (2a) and octadecane-1,10-diyl dihexanoate (2b); octadecane-1,9-diyl bis(decanoate) (3a) and octadecane-1,10-diyl bis(decanoate) (3b); octadecane-1,9-diyl dioctanoate (4a) and octadecane-1,10-diyl dioctanoate (4b); ocatadecane-1,9-diyl didodecanoate (5a) and ocatadecane-1,10-diyl didodecanoate (5b); and mixtures thereof. 
     
     
         11 . The lubricant composition of  claim 1 , further comprising a base oil selected from the group consisting of Group I oils, Group II oils, Group III oils, and combinations thereof. 
     
     
         12 . The lubricant composition of  claim 1 , further comprising one or more ester species selected from the group consisting of monoesters, diesters, triesters, and combinations thereof. 
     
     
         13 . The lubricant composition of  claim 1 , wherein individual diester isomers 1a and 1b, of which the isomeric mixture of diester species is comprised, differ in relative amount by not more than 5 percent. 
     
     
         14 . A method comprising the steps of:
 a) converting a quantity of mono-unsaturated free lipid species, having a carbon number of from 10 to 22, to an isomeric mixture of diol species having the same carbon number as the free lipid species from which they were derived, wherein said converting proceeds via an epoxide intermediate species; and   b) esterifying the isomeric mixture of diol species with an esterifying species to form an isomeric mixture of diester species, wherein the isomeric mixture of diester species comprises the following isomerically-related structures:   
       
         
           
           
               
               
           
         
       
       wherein R 1  and R 2  are the same or independently selected from C 2  to C 20  hydrocarbon groups, and wherein n and m are the same or independently selected from the group of integers 2 to 20. 
     
     
         15 . The method of  claim 14 , wherein the step of esterifying the isomeric mixture of diol species with an esterifying species involves a catalyst selected from the group consisting of an acid catalyst and a base catalyst. 
     
     
         16 . The method of  claim 14 , wherein the step of esterifying the isomeric mixture of diol species with an esterifying species involves conversion of a fatty acid to a species selected from the group consisting of an acyl halide species, itself selected from the group consisting of acyl chlorides, acyl bromides, acyl iodides, and combinations thereof, and an acyl anhydride species. 
     
     
         17 . The method of  claim 14 , wherein the step of converting comprises the following sub-steps:
 a) epoxidizing the quantity of mono-unsaturated free lipid species to yield a quantity of epoxidized lipid species; and   b) reducing the epoxidized lipid species to yield an isomeric mixture of diol species.   
     
     
         18 . The method of  claim 17 , wherein the substep of epoxidizing utilizes a regent selected from the group consisting of peroxides and peroxy acids. 
     
     
         19 . The method of  claim 17 , wherein the substep of reducing utilizes a metal-hydride reducing agent. 
     
     
         20 . The method of  claim 14 , wherein the step of converting comprises the following sub-steps:
 a) reducing the quantity of mono-unsaturated free lipid species to yield a quantity of mono-unsaturated fatty alcohol species;   b) epoxidizing the quantity of mono-unsaturated fatty alcohol species to yield a quantity of epoxidized alcohol species; and   c) reducing the epoxidized alcohol species to yield an isomeric mixture of diol species.   
     
     
         21 . The method of  claim 20 , wherein the substeps of reducing the quantity of mono-unsaturated free lipid species and reducing the epoxidized alcohol species utilize one or more metal-hydride reducing agents. 
     
     
         22 . The method of  claim 20 , wherein the substep of epoxidizing the quantity of mono-unsaturated fatty alcohol species utilizes an oxidizing agent selected from the group consisting of peroxides and peroxy acids. 
     
     
         23 . The method of  claim 14 , further comprising a step of blending the isomeric mixture of diester species with one or more other ester species selected from the group consisting of triesters, diesters, monoesters, and combinations thereof. 
     
     
         24 . The method of  claim 14 , wherein the isomeric mixture of diester species is entirely bio-derived. 
     
     
         25 . The method of  claim 14 , further comprising a step of blending the isomeric mixture of diester species with a base oil selected from the group consisting of Group I oils, Group II oils, Group III oils, and combinations thereof.