Synthesis of r-glucosides, sugar alcohols, reduced sugar alcohols, and furan derivatives of reduced sugar alcohols

Abstract

Disclosed herein are methods for synthesizing 1,2,5,6-hexanetetrol (HTO), 1,6 hexanediol (HDO) and other reduced polyols from C5 and C6 sugar alcohols or R glycosides. The methods include contacting the sugar alcohol or R-glycoside with a copper catalyst, most desirably a Raney copper catalyst with hydrogen for a time, temperature and pressure sufficient to form reduced polyols having 2 to 3 fewer hydoxy groups than the starting material. When the starting compound is a C6 sugar alcohol such as sorbitol or R-glycoside of a C6 sugar such as methyl glucoside, the predominant product is HTO. The same catalyst can be used to further reduce the HTO to HDO.

1 . A method of making 2,5-bis(hydroxymethyl)tetrahydrofuran, comprising: contacting a mixture comprising 1,2,5,6-hexanetetrol with an acid catalyst selected from the group consisting of sulfuric acid, phosphonic acid, carbonic acid and a water tolerant non-Bronsted Lewis acid for a time and at a temperature and a pressure sufficient to convert the 1,2,5,6-hexanetetrol to 2,5 bis(hydroxymethyl)tetrahydrofuran. 
     
     
         2 . The method of  claim 1 , wherein the non-Bronsted Lewis acid is a triflate compound. 
     
     
         3 . The method of  claim 2 , wherein the triflate compound is selected from the group consisting of bismuth triflate, scandium triflate, and sulfuric acid. 
     
     
         4 . (canceled) 
     
     
         5 . (canceled) 
     
     
         6 . The method of  claim 1  wherein the wherein the mixture is contacted with the catalyst under vacuum pressure of less than 0.4 psi. 
     
     
         7 . The method  claim 1  wherein the acid catalyst is sulfuric acid. 
     
     
         8 . The method of  claim 1 , wherein the acid catalyst is the non-Bronsted Lewis acid. 
     
     
         9 . The method of  claim 1 , wherein the acid catalyst is carbonic acid formed by adding of CO 2  to the reaction mixture at a pressure sufficient to form carbonic acid. 
     
     
         10 . (canceled) 
     
     
         11 . (canceled) 
     
     
         12 . The method of  claim 1  wherein the mixture further includes 1,4,5 hexanetriol and contacting with the acid catalyst further converts the 1,4,5 hexanetriol to 2-hydroxyethyl tetrahydrofuran. 
     
     
         13 . The method of  claim 12  further including separating the 2-hydroxyethyl tetrahydrofuran from the 2,5-bis(hydroxymethyl)tetrahydrofuran. 
     
     
         14 . The method of  claim 1 , wherein the acid catalyst is present in an amount between 0.5 mol % and 5 mol % based on the amount of the 1,2,5,6-hexanetetrol. 
     
     
         15 . The method of  claim 1 , further comprising separating the 2,5-bis(hydroxymethyl) tetrahydrofuran from the mixture and contacting the separated 2,5-bis(hydroxymethyl)tetrahydrofuran with a rhenium oxide catalyst for a time and a temperature sufficient to convert the 2,5-bis(hydroxymethyl)tetrahydrofuran to 1,6 hexanediol. 
     
     
         16 . The method of  claim 14  wherein the rhenium oxide catalyst further comprises silicon oxide. 
     
     
         17 . A method of making 2 hydroxy ethyl tetrahydrofuran comprising, contacting a mixture comprising 1,4,5 hexanetriol with an acid catalyst selected from the group consisting of sulfuric acid, phosphonic acid, carbonic acid, and a water tolerant non-Bronsted Lewis acid for a time, and at pressure and temperature sufficient to convert the 1,4,5 hexanetriol to 2 hydroxy ethyl tetrahydrofuran. 
     
     
         18 . The method of  claim 17 , wherein the water tolerant non-Bronsted Lewis acid catalyst is a triflate compound. 
     
     
         19 . The method of  claim 18  wherein the tiflate compound is selected from the group consisting of bismuth triflate, scandium triflate, and sulfuric acid. 
     
     
         20 . (canceled) 
     
     
         21 . (canceled) 
     
     
         22 . (canceled) 
     
     
         23 . The method  claim 17  wherein the acid catalyst is sulfuric acid. 
     
     
         24 . The method of  claim 17 , wherein the acid catalyst is the water-tolerant non-Bronsted Lewis acid. 
     
     
         25 . The method of  claim 17 , wherein the acid catalyst is phosphonic acid.