Polytrimethylene ether glycol esters

Abstract

Disclosed are monocarboxylic acid esters (mono- and/or diesters) of polytrimethylene ether glycol that are substantially free of residues from the catalyst used to produce the polytrimethylene ether glycol esters, as well as methods for their preparation and end uses thereof.

1 . A composition comprising a monocarboxylic acid ester of a polytrimethylene ether glycol, obtained by the esterification of the polytrimethylene ether glycol with a monocarboxylic acid and/or a monocarboxylic acid equivalent in the presence of an acid catalyst, wherein the composition is substantially free of an acid ester residue from the acid catalyst. 
     
     
         2 . The composition of  claim 1 , wherein the polytrimethylene ether glycol is prepared from the polycondensation of hydroxyl groups-containing monomers predominantly comprising 1,3-propanediol obtained biochemically from a renewable source. 
     
     
         3 . The composition of  claim 1 , wherein the polytrimethylene ether glycol has a number average molecular weight of from about 250 to about 5000, and a polydispersivity of from about 1.0 to about 2.2. 
     
     
         4 . The composition of  claim 1 , wherein the monocarboxylic acid or monocarboxylic acid equivalent is derived from a natural source or is bio-dervied. 
     
     
         5 . The composition of  claim 1 , wherein the polytrimethylene ether glycol is esterified with a monocarboxylic acid of the formula R—COOH, wherein R is an organic group containing from 6 to 40 carbon atoms. 
     
     
         6 . The composition of  claim 1 , wherein the monocarboxylic acid is selected from 20 the group consisting of lauric, myristic, palmitic, stearic, arachidic, benzoic, caprylic, palmitic, erucic, palmitoleic, pentadecanoic, heptadecanoic, nonadecanoic, linoleic, arachidonic, oleic, valeric, caproic, capric and 2-ethylhexanoic acid, and mixtures thereof. 
     
     
         7 . The composition of  claim 1 , wherein the monocarboxylic acid comprises 2-ethylhexanoic acid, benzoic acid, stearic acid and/or oleic acid. 
     
     
         8 . The composition of  claim 1 , comprising from about 50 to 100 wt % diester, and from 0 to about 50 wt % monoester, based on the weight of the composition. 
     
     
         9 . The composition of  claim 1 , comprising from about 75 to 100 wt % diester, and from 0 to about 25 wt % monoester, based on the weight of the ocmposition. 
     
     
         10 . The composition of  claim 1 , comprising one or more compounds of the formula (I): 
       
         
           
           
               
               
           
         
       
       wherein Q represents the residue of a polytrimethylene ether glycol after abstraction of the hydroxyl groups, R 2  is H or R 3 CO, and each of R 1  and R 3  is individually a substituted or unsubstituted aromatic, saturated aliphatic, unsaturated aliphatic, or cycloaliphatic organic group containing from 6 to 40 carbon atoms. 
     
     
         11 . The composition of  claim 1 , consisting essentially of one or more compounds of the formula (I): 
       
         
           
           
               
               
           
         
       
       wherein Q represents the residue of a polytrimethylene ether glycol after abstraction of the hydroxyl groups, R 2  is H or R 3 C(O), and each of R 1  and R 3  is individually a substituted or unsubstituted aromatic, saturated aliphatic, unsaturated aliphatic, or cycloaliphatic organic group containing from 6 to 40 carbon atoms. 
     
     
         12 . The composition of  claim 1 , wherein the acid catalyst comprises sulfuric acid, and the composition contains less than about 20 ppmof sulfur. 
     
     
         13 . Functional fluids comprising the composition of  claim 1 . 
     
     
         14 . A process for preparing a composition comprising a monocarboxylic acid ester of a polytrimethylene ether glycol comprising the steps of:
 (a) polycondensing a hydroxyl-groups containing reactant comprising at least 50 mole % 1,3-propanediol reactant in the presence of a first acid catalyst to obtain a polytrimethylene ether glycol composition comprising a polytrimethylene ether glycol;   (b) esterifying the polytrimethylene ether glycol from the polytrimethylene ether glycol composition by heating it with a monocarboxylic acid of the formula R—COOH, wherein R is an organic group containing from 6 to 40 carbon atoms, and/or a monocarboxylic acid equivalent thereof, in the presence of a second acid catalyst to obtain a crude polytrimethylene ether glycol ester containing a residual acid ester of the second acid catalyst, the first acid catalyst or both;   (c) hydrolyzing a substantial portion of the residual acid ester in the crude ester by heating with wafer to form a mixture of water and polytrimethylene ether glycol ester;   (d) removing a substantial portion of the water to obtain a substantially dry polytrimethylene ether glycol ester that is substantially free of the residual acid ester.   
     
     
         15 . The process of  claim 14 , wherein the first acid catalyst is a first mineral acid catalyst, and the second acid catalyst is a second mineral acid catalyst. 
     
     
         16 . The process of  claim 15 , wherein the first and second mineral acid catalysts are the same. 
     
     
         17 . The process of  claim 16 , wherein the second mineral acid catalyst comprises the first mineral acid catalyst. 
     
     
         18 . The process of  claim 14 , carried out in the substantial absence of an organic solvent. 
     
     
         19 . The process of  claim 14 , wherein the first and second acid catalysts are individually selected from the group consisting of sulfuric acid, phosphoric acid, hydrochloric acid, hydroiodic acid, a zeolite, a heteropolyacid, an amberlyst, an ion exchange resin and mixtures thereof. 
     
     
         20 . The process of  claim 14 , wherein the first and second acid catalysts comprise sulfuric acid. 
     
     
         21 . The process of  claim 14 , wherein the monocarboxylic acid comprises 2-ethylhexanoic acid, benzoic acid, stearic acid and/or oleic acid. 
     
     
         22 . The process of  claim 14 , wherein the polytrimethylene ether glycol ester comprises from about 50 to 100 wt % diester, and from 0 to about 50 wt % monoester, based on the weight of the polytrimethylene ether glycol ester. 
     
     
         23 . The process of  claim 14 , wherein the 1,3-propanediol is produced by a fermentation process using a renewable biological source. 
     
     
         24 . The process of  claim 14 , wherein the number average molecular weight of the polytrimethylene ether glycol is from about 250 to about 5000.