Liquid metal catalyst for biodiesel production

Abstract

Molten metal or molten metal alloy catalysts for transesterification reactions are provided. In particular, readily available molten tin is used as a catalyst for biodiesel production. Catalysts comprising tin alloys with low melting point temperatures to allow for low operation temperatures are also provided. The molten catalysts remain in the reaction zone and do not contaminate the product stream, thereby product separation and recovery are manageable. By using molten tin catalysts, it is possible to produce a high quality glycerol as a second valuable product. Furthermore, wide quality ranges of reactants (alcohol and oil) are available for biodiesel production with molten tin catalysts.

1 . A method of producing biodiesel through transesterification, said method comprising:
 (a) introducing multiple reactants into a reaction zone, wherein said reactants comprise at least a feedstock oil and an alcohol;   (b) having a catalyst in said reaction zone, wherein said catalyst comprises a molten metal or a molten metal alloy; and   (c) reacting said multiple reactants to form biodiesel and glycerol in said reaction zone, wherein said reaction is catalyzed by said catalyst.   
     
     
         2 . The method as set forth in  claim 1 , wherein said catalyst comprises molten tin. 
     
     
         3 . The method as set forth in  claim 1 , wherein said catalyst comprises molten tin alloyed with at least a second metal. 
     
     
         4 . The method as set forth in  claim 3 , wherein said second metal is selected from the group consisting of lead, indium, bismuth, copper, antimony, and silver. 
     
     
         5 . The method as set forth in  claim 3 , wherein said molten tin alloyed with said second metal has a lower melting point than the melting point of unalloyed tin. 
     
     
         6 . The method as set forth in  claim 1 , further comprising removing said products from said reaction zone, wherein all of said catalyst remains in said reaction zone. 
     
     
         7 . The method as set forth in  claim 1 , wherein said feedstock oil of said reactants is selected from the group consisting of tri-glycerides, di-glycerides, mono-glycerides, and free fatty acids. 
     
     
         8 . The method as set forth in  claim 1 , wherein said alcohol of said reactants comprises a short chain linear alcohol or a branched alcohol. 
     
     
         9 . The method as set forth in  claim 8 , wherein said alcohol is selected from the group consisting of methanol, ethanol, propanol, and butanol. 
     
     
         10 . The method as set forth in  claim 1 , wherein said alcohol of said reactants comprises wet ethanol. 
     
     
         11 . The method as set forth in  claim 1 , further comprising heating said reaction zone to a reaction temperature, wherein said reaction temperature is greater than or equal to the melting point of said catalyst. 
     
     
         12 . The method as set forth in  claim 1 , further comprising establishing an operating pressure in said reaction zone, wherein said operating pressure is greater than or equal to atmospheric pressure. 
     
     
         13 . The method as set forth in  claim 1 , wherein the molar ratio of said alcohol to said feedstock oil ranges from 3:1 to 50:1. 
     
     
         14 . A method of catalyzing a transesterificaton reaction, said method comprising:
 (a) introducing multiple reactants into a reaction zone, wherein said reactants comprise a first alcohol and a first ester;   (b) having a catalyst in said reaction zone, wherein said catalyst comprises a molten metal or a molten metal alloy; and   (c) reacting said multiple reactants to form multiple products, wherein said products comprise a second alcohol and a second ester, wherein said second ester is different from said first ester, and wherein said reaction is catalyzed by said catalyst.   
     
     
         15 . A method of producing an ester from a carboxylic acid, said method comprising:
 (a) introducing multiple reactants into a reaction zone, wherein said reactants comprise said carboxylic acid and an alcohol;   (b) having a catalyst in said reaction zone, wherein said catalyst comprises a molten metal or a molten metal alloy; and   (c) reacting said multiple reactants to form a product, wherein said products comprise said ester and water, and wherein said reaction is catalyzed by said catalyst.