Charged Polymers for Ethanol Dehydration

Abstract

The systems and methods described herein provide for modified lignins and other compositions that may be useful as entrainers. In embodiments, they may be useful for dehydrating ethanol so that it can be used as an energy source.

1 . A method for dehydrating an ethanol solution comprising distilling the ethanol solution in the presence of a molecular sieve characterized by a porous core and a water-permeable polymeric coating impermeable to ethanol. 
     
     
         2 . The method in accordance with  claim 1  wherein the surface of the molecular sieve is characterized by a high charge density. 
     
     
         3 . The method in accordance with  claim 2  wherein the coating has a thickness of less than about 100 nm. 
     
     
         4 . The method in accordance with  claim 2  wherein the coating comprises pores having a mean diameter less than 4 Angstroms. 
     
     
         5 . The method in accordance with  claim 1  wherein the porous core comprises silica or a polyanionic polymer. 
     
     
         6 . The method in accordance with  claim 5  wherein the coating comprises a polycationic polymer. 
     
     
         7 . The method in accordance with  claim 6  wherein the polycationic polymer is crosslinked. 
     
     
         8 . The method in accordance with  claim 6  further comprising an additional coating comprising a polyanionic polymer. 
     
     
         9 . The method in accordance with  claim 3  wherein the coating comprises a nonionic polymer. 
     
     
         10 . The method in accordance with  claim 1  wherein the porous core comprises a polycationic polymer. 
     
     
         11 . The method in accordance with  claim 10  wherein the coating comprises a polyanionic polymer. 
     
     
         12 . The method in accordance with  claim 11  wherein the polyanionic polymer is crosslinked. 
     
     
         13 . The method in accordance with  claim 11  further comprising an additional coating comprising a polycationic polymer. 
     
     
         14 . The method in accordance with  claim 10  wherein the coating comprises a nonionic polymer. 
     
     
         15 . A molecular sieve characterized by a porous core and a water-permeable polymeric coating impermeable to ethanol. 
     
     
         16 . The molecular sieve in accordance with  claim 15  comprising the porous core comprises a polyanionic polymer. 
     
     
         17 . The molecular sieve in accordance with  claim 16  wherein the coating comprises a polycationic polymer. 
     
     
         18 . The molecular sieve in accordance with  claim 17  wherein the polycationic polymer the coating has a thickness of less than about 100 nm. 
     
     
         19 . The molecular sieve in accordance with  claim 15  comprising the porous core comprises a polycationic polymer. 
     
     
         20 . The molecular sieve in accordance with  claim 19  wherein the coating comprises a polyanionic polymer. 
     
     
         21 . The molecular sieve in accordance with  claim 20  wherein the polyanionic polymer the coating has a thickness of less than about 100 nm. 
     
     
         22 . A method for dehydrating an ethanol solution comprising distilling the ethanol solution in the presence of an entrainer comprising a lignin or lignin derivative. 
     
     
         23 . The method in accordance with  claim 22  wherein the entrainer is a carboxylated lignin. 
     
     
         24 . The method in accordance with  claim 22  wherein the entrainer is produced by reacting a lignin with an anhydride. 
     
     
         25 . The method in accordance with  claim 24  wherein the anhydride is a succinic anhydride. 
     
     
         26 . The method in accordance with  claim 24  wherein the anhydride is an alkylated succinic anhydride. 
     
     
         27 . The method in accordance with  claim 22  wherein the lignin is a kraft lignin characterized by hydroxyl groups. 
     
     
         28 . The method in accordance with  claim 27  wherein between about 50 and 100% of the hydroxyl groups are functionalized. 
     
     
         29 . The method in accordance with  claim 22  wherein the entrainer is a solid. 
     
     
         30 . The method in accordance with  claim 23  wherein the entrainer is further characterized by a hydrophilic polymer substituent. 
     
     
         31 . The method in accordance with  claim 30  wherein the hydrophilic polymer substituent is selected from the group consisting of a polyethylene oxide and a polypropylene oxide. 
     
     
         32 . The method in accordance with  claim 31  wherein the hydrophilic polymer substituent is selected from the group consisting of a polyethylene oxide diglycidyl ether and a polypropylene oxide diglycidyl ether. 
     
     
         33 . The method in accordance with  claim 32  wherein the hydrophilic polymer substituent has a molecular weight between about 700 and 2500 g/mol.