Method for preparing a composition containing at least one internal dehydration product for a hydrogenated sugar

Abstract

The subject of the present invention is a novel method for preparing a composition of internal dehydration product of a hydrogenated sugar, comprising: a) a step of distilling a medium containing the said internal dehydration product in order to obtain a distillate enriched with this product, b) optionally, at least one subsequent step of purifying the distillate thus obtained, c) a subsequent step of bringing the distillate obtained during step a), and then optionally subjected to step b), into contact with an agent capable of improving the stability of the internal dehydration product predominantly contained in the distillate, the said agent not being in gaseous form, d) optionally, a subsequent step of shaping the resulting composition of internal dehydration product of a hydrogenated sugar. This method makes it possible in particular to obtain a stable isosorbide composition, characterized by its purity and/or its content of certain stabilizing or nonstabilizing species.

1 . Method for preparing a composition of internal dehydration product of a hydrogenated sugar, comprising: 
 a) a step of distilling a medium containing the said internal dehydration product in order to obtain a distillate enriched in this product,    b) optionally, at least one subsequent step of purifying the distillate thus obtained,    c) a subsequent step of bringing the distillate obtained during step a), and then optionally subjected to step b), into contact with an agent capable of improving the stability of the internal dehydration product predominantly contained in the distillate, the said agent not being in gaseous form,    d) optionally, a subsequent step of shaping the resulting composition of internal dehydration product of a hydrogenated sugar.    
     
     
         2 . Method according to  claim 1 , wherein the agent used in step c) is selected from the group consisting of reducing agents, antioxidants, oxygen scavengers, light stabilizers, anti-acid agents, metal-deactivating agents and any mixtures of at least any two of these products.  
     
     
         3 . Method according to  claim 1 , wherein the agent used in step c) is selected from the group consisting of compounds based on boron, compounds based on sodium, compounds based on potassium, compounds based on phosphorus, compounds based on nitrogen, compounds based on sulphur, aromatic compounds, compounds containing at least one alcohol functional group and any mixtures of at least any two of these products.  
     
     
         4 . Method according to  claim 1 , wherein the agent used in step c) is used in an amount of 0.0001 to 2%, these percentages being expressed by dry weight of the said agent relative to the dry weight of the internal dehydration product of a hydrogenated sugar predominantly present in the distillate.  
     
     
         5 . Method according to  claim 4 , wherein the agent is used in an amount of 0.001 to 2%, preferably 0.002 to 1.5% and still more preferably 0.003 to 1.5%.  
     
     
         6 . Method according to  claim 5 , wherein the agent is used in an amount of 0.005 to 1%.  
     
     
         7 . Method according to  claim 6 , wherein the agent consists of sodium borohydride (NaBH 4 ) or an antioxidant.  
     
     
         8 . Method according to  claim 4 , wherein the agent is used in an amount of 0.0001 to 0.5%, preferably 0.0003 to 0.3%.  
     
     
         9 . Method according to  claim 8 , wherein the agent is used in an amount of 0.0003 to 0.1%.  
     
     
         10 . Method according to  claim 9 , wherein the agent is used in an amount of 0.0003 to 0.01%.  
     
     
         11 . Method according to  claim 9 , wherein the agent consists of a reducing agent or of an anti-acid agent, the anti-acid agent being preferably selected from alkaline agents.  
     
     
         12 . Method according to  claim 11 , wherein the agent is a sodium salt.  
     
     
         13 . Method according to  claim 1 , wherein the agent used in step c) has a solubility in water at 20° C. at least equal to 0.01%, preferably at least equal to 0.1%.  
     
     
         14 . Method according to  claim 1 , wherein step a) of distillation is followed by a step b) of purification, preferably a step b) of purification during which the distillate is treated, in any order, with at least one activated charcoal and with at least one ionic or nonionic resin.  
     
     
         15 . Method according to  claim 1 , comprising at least one concentration step carried out, completely or partly, prior to or simultaneously with step c).  
     
     
         16 . Composition containing at least one internal dehydration product of a hydrogenated sugar, containing from 0.0001 to 2% of an agent selected from the group consisting of reducing agents, anti-oxidants, oxygen scavengers, light stabilizers, anti-acid agents, metal-deactivating agents and any mixtures of at least any two of these products, these percentages being expressed by dry weight of the said agent relative to the dry weight of the internal dehydration product of a hydrogenated sugar predominantly present in the said composition.  
     
     
         17 . Composition according to  claim 16 , containing from 0.005 to 1% of an agent consisting of sodium borohydride or of an antioxidant.  
     
     
         18 . Composition according to  claim 16 , containing from 0.0003 to 0.1% of an agent consisting of a reducing agent or of an anti-acid agent, the anti-acid agent being preferably selected from alkaline agents.  
     
     
         19 . Composition containing at least one internal dehydration product of a hydrogenated sugar, containing from 0.0001 to 1% of an element selected from the group consisting of boron, sodium, potassium, phosphorus, sulphur or nitrogen, these percentages being expressed by dry weight of the said element relative to the dry weight of the internal dehydration product of a hydrogenated sugar predominantly present in the said composition.  
     
     
         20 . Composition according to  claim 19 , containing from 0.0001 to 0.01% of an element selected from the group consisting of boron, sodium, potassium, phosphorus, sulphur or nitrogen.  
     
     
         21 . Composition containing at least one internal dehydration product of a hydrogenated sugar, being stable and having a purity of less than 99.8%, in particular a purity of between about 98.0 and 99.7%.  
     
     
         22 . Composition according to  claim 16  or  claim 19 , having a formic acid content of less than 0.0005% and a content of monoanhydrohexoses of less than 0.005%, these percentages being expressed by dry weight relative to the dry weight of the internal dehydration product of a hydrogenated sugar predominantly present in the said composition.  
     
     
         23 . Composition according to  claim 16  or  claim 19 , being an isosorbide composition.  
     
     
         24 . Composition according to claims  16  or  claim 19 , having a stability of at least two months, preferably of at least six months, and still more preferably of at least one year.  
     
     
         25 . Composition according to  claim 16  or  claim 19 , having a pH greater than 5, preferably greater than 6 and still more preferably of between about 6.5 and 9.5.  
     
     
         26 . Composition according to  claim 25 , having a pH of between about 7 and 9.  
     
     
         27 . Composition according to  claim 16  or  claim 19 , having a dry matter content of between 50 and 90%, preferably between 75 and 88%.  
     
     
         28 . Polymeric or nonpolymeric, biodegradable or nonbiodegradable products and mixtures intended in particular for the chemical, pharmaceutical, cosmetic or food industries, containing a composition according to  claim 1.