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 molar excess of low-molecular-weight olefins in the presence of a metathesis catalyst. In certain embodiments, the methods further include separating at least a portion of the unreacted low-molecular-weight olefins. In certain embodiments, the methods further include recycling the separated unreacted low-molecular-weight olefins.

What is claimed is: 
     
         1 . A method of refining a natural oil, comprising:
 providing (a) a feedstock comprising natural oil glycerides, and (b) a molar excess low-molecular-weight olefins, relative to the natural oil glycerides;   cross-metathesizing the natural oil glycerides with a portion of the low-molecular-weight olefins in the presence of a metathesis catalyst to provide (a) unreacted low-molecular-weight olefins, and (b) a metathesized product comprising olefins and metathesized glycerides; and   separating at least a portion of the unreacted low-molecular-weight olefins from the metathesized product.   
     
     
         2 . The method of  claim 1 , wherein the molar excess of low-molecular-weight olefins is at least a 50% molar excess. 
     
     
         3 . The method of  claim 1 , wherein the molar excess of low-molecular-weight olefins is at least a 100% molar excess. 
     
     
         4 . The method of  claim 1 , wherein the molar excess of low-molecular-weight olefins is at least a 200% molar excess. 
     
     
         5 . The method of  claim 1 , comprising carrying out the cross-metathesis in a first metathesis reactor. 
     
     
         6 . The method of  claim 5 , further comprising:
 recycling the separated unreacted low-molecular-weight olefins to the first metathesis reactor.   
     
     
         7 . The method of  claim 5 , further comprising:
 providing a second metathesis reactor; and   recycling at least a portion of the separated unreacted low-molecular-weight olefins to the second metathesis reactor.   
     
     
         8 . The method of  claim 1 , further comprising: separating the olefins of the metathesized product and the metathesized glycerides of the metathesized product to provide a first stream comprising separated olefins and a second stream comprising separated metathesized glycerides. 
     
     
         9 . The method of  claim 8 , further comprising transesterifying the separated metathesized glycerides of the second stream in the presence of an alcohol to provide a transesterified product comprising glycerin and fatty acid esters having no glycerin backbone. 
     
     
         10 . The method of  claim 9 , wherein the alcohol is methanol or ethanol. 
     
     
         11 . The method of  claim 9 , wherein the fatty acid esters comprise esters of 9-decenoic acid. 
     
     
         12 . The method of  claim 10 , wherein the fatty acid esters comprise methyl 9-decenoate or ethyl 9-decenoate. 
     
     
         13 . The method of  claim 1 , wherein the low-molecular-weight olefins comprise ethylene, propylene, 1-butene, 2-butene, or any combinations thereof. 
     
     
         14 . The method of  claim 13 , wherein the low-molecular-weight olefins are ethylene. 
     
     
         15 . The method of  claim 14 , wherein the metathesized product comprises 1-decene and glycerides of 9-decenoic acid. 
     
     
         16 . The method of  claim 13 , wherein the low-molecular-weight olefins are 1-butene. 
     
     
         17 . The method of  claim 16 , wherein the metathesized product comprises 1-decene, 3-dodecene, glycerides of 9-decenoic acid, and glycerides of 9-dodecenoic acid. 
     
     
         18 . The method of  claim 1 , wherein the low-molecular-weight olefins comprise alpha-olefins having 4 to 10 carbon atoms. 
     
     
         19 . The method of  claim 1 , wherein the natural oil glycerides are derived from vegetable oils, algae oils, animal fats, or any combinations thereof. 
     
     
         20 . The method of  claim 19 , wherein the natural oil glycerides are derived from a vegetable oil, wherein the vegetable oil is canola oil, rapeseed oil, coconut oil, corn oil, cottonseed oil, olive oil, palm oil, peanut oil, safflower oil, sesame oil, soybean oil, sunflower oil, linseed oil, palm kernel oil, tung oil, jatropha oil, mustard oil, pennycress oil, camelina oil, castor oil, or any combination thereof. 
     
     
         21 . A method of refining a natural oil, comprising:
 providing (a) a feedstock comprising natural oil glycerides, and (b) at least a 200% molar excess of 1-butene, relative to the natural oil glycerides;   cross-metathesizing the natural oil glycerides with a portion of the 1-butene in a metathesis reactor in the presence of a metathesis catalyst to provide (a) unreacted 1-butene, and (b) a metathesized product comprising 1-decene, 3-dodecene, glycerides of 9-decenoic acid, and glycerides of 9-dodecenoic acid;   separating at least a portion of the unreacted 1-butene from the metathesized product; and   recycling at least a portion of the separated unreacted 1-butene to the metathesis reactor.   
     
     
         22 . The method of  claim 21 , wherein the weight-to-weight ratio of 1-decene to 3-dodecene is at least 1.0. 
     
     
         23 . The method of  claim 21 , wherein the weight-to-weight ratio of 1-decene to 3-dodecene is from 1.0 to 1.5. 
     
     
         24 . A method of refining a natural oil, comprising:
 providing (a) a feedstock comprising natural oil glycerides, and (b) at least a 300% molar excess of ethylene, relative to the natural oil glycerides;   cross-metathesizing the natural oil glycerides with a portion of the ethylene in a metathesis reactor in the presence of a metathesis catalyst to provide (a) unreacted ethylene, and (b) a metathesized product comprising 1-decene and glycerides of 9-decenoic acid;   separating at least a portion of the unreacted ethylene from the metathesized product;   recycling at least a portion of the separated unreacted ethylene to the metathesis reactor.