Methods of refining and producing fuel and specialty chemicals from natural oil feedstocks

Abstract

Methods are provided for refining natural oil feedstocks. The methods include reacting the feedstock with a low-molecular-weight olefin or mid-weight olefin in the presence of a metathesis catalyst under conditions sufficient to form a metathesized product including olefins and esters. In certain embodiments, the methods further include separating the olefins from the esters in the metathesized product. In certain embodiments, the methods further include transesterifying the esters in the presence of an alcohol to form a transesterified product.

What is claimed is: 
     
         1 . A method of refining a natural oil, comprising:
 providing a feedstock comprising a natural oil;   providing a low-molecular-weight olefin or mid-weight olefin;   reacting the feedstock and the low-molecular-weight olefin or mid-weight olefin in a metathesis reactor in the presence of a metathesis catalyst to form a metathesized product comprising olefins and esters;   separating the olefins in the metathesized product from the esters in the metathesized product; and   transesterifying the esters in the presence of an alcohol to form a transesterified product.   
     
     
         2 . The method of  claim 1 , wherein the low-molecular-weight olefin comprises at least one olefin selected from the group consisting of ethylene, propylene, 1-butene, 2-butene, isobutene, 1-pentene, 2-pentene, 3-pentene, 2-methyl-1-butene, 2-methyl-2-butene, 3-methyl-1-butene, cyclopentene, 1,4-pentadiene, 1-hexene, 2-hexene, 3-hexene, 4-hexene, 2-methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 2-methyl-2-pentene, 3-methyl-2-pentene, 4-methyl-2-pentene, 2-methyl-3-pentene, and cyclohexene. 
     
     
         3 . The method of  claim 1 , wherein the low-molecular-weight olefin comprises at least one olefin selected from the group consisting of ethylene, propylene, 1-butene, 2-butene, and isobutene. 
     
     
         4 . The method of  claim 1 , wherein the low-molecular-weight olefin is 3-hexene. 
     
     
         5 . The method of  claim 1 , further comprising self-metathesizing the low-molecular-weight olefin or mid-weight olefin in the presence of a second metathesis catalyst prior to the metathesis reaction with feedstock, forming a metathesized low-molecular-weight olefin or metathesized mid-weight olefin. 
     
     
         6 . The method of  claim 5 , wherein the low-molecular-weight olefin or mid-weight olefin is an alpha-olefin. 
     
     
         7 . The method of  claim 5 , wherein the second metathesis catalyst is a rhenium oxide catalyst or tungsten oxide catalyst. 
     
     
         8 . The method of  claim 5 , further comprising isomerizing the metathesized low-molecular-weight olefin or metathesized mid-weight olefin prior to the metathesis reaction with the feedstock. 
     
     
         9 . The method of  claim 1 , further comprising isomerizing the low-molecular-weight olefin or mid-weight olefin prior to the metathesis reaction with the feedstock. 
     
     
         10 . The method of  claim 1 , further comprising separating C 10+  olefins from the olefin in the metathesized product. 
     
     
         11 . The method of  claim 10 , further comprising reacting the C 10+  olefins with ethylene in the presence of a second metathesis catalyst. 
     
     
         12 . The method of  claim 11 , wherein the second metathesis catalyst is a rhenium oxide catalyst or tungsten oxide catalyst. 
     
     
         13 . The method of  claim 1 , further comprising self-metathesizing the olefins in the metathesized product in the presence of a second metathesis catalyst. 
     
     
         14 . The method of  claim 13 , wherein the second metathesis catalyst is a rhenium oxide catalyst or tungsten oxide catalyst. 
     
     
         15 . The method of  claim 1 , wherein the transesterified product comprises C 10  methyl esters and C 12+  methyl esters, further comprising separating the C 10  methyl esters from the C 12+  methyl esters. 
     
     
         16 . The method of  claim 15 , further comprising reacting the C 10  methyl esters with 1-butene in the presence of a metathesis catalyst. 
     
     
         17 . The method of  claim 1 , further comprising recycling a portion of the transesterified product to the metathesis reactor. 
     
     
         18 . The method of  claim 17 , further comprising conducting a glycerolysis reaction on the recycled transesterified product prior to introduction to the metathesis reactor. 
     
     
         19 . The method of  claim 18 , wherein the recycled transesterified product is combined with the low-molecular-weight olefin or mid-weight olefin prior to the glycerolysis reaction.