Methods and systems for preparing materials for sucralose production

Abstract

The present invention provides a method for preparing DMF for sucralose production, including, e.g., isolating DMF from a composition comprising DMF, water, and methanol, using a single-tower rectification system. In various embodiments of the present invention, the composition, after the removal of water and methanol, may be further dried/dehydrated, such as, by using a dehydration agent and/or filtration. The resulting substantially pure DMF may comprise at least about 98-99% DMF. The present invention further provides a method of preparing a composition comprising anhydrous sucrose for sucralose production, which may comprise mixing regular sucrose with a water-containing DMF composition, and drying the resulting sucrose-DMF composition. Also provided is a single-tower separation system for isolating DMF from a composition comprising DMF, water, and methanol.

1 . A method for isolating N,N-dimethylformamide (“DMF”) from a composition comprising DMF, water, and methanol, comprising:
 introducing a composition comprising DMF, water, and methanol into a into a single-tower separation system, the single tower separation system comprising a lower section and an upper section, and the composition being introduced into the lower section; 
 heating the composition; 
 isolating DMF from the composition; and drying the isolated DMF, whereby to a substantially pure DMF is produced; and 
 the heating of the composition comprising the steps of: 
 reducing the pressure of the separation system by using a vacuum system; 
 maintaining the temperatures of the lower section at about 25-45° C., whereby methanol is substantially removed from the composition; and 
 maintaining the temperatures of the lower section at about 45-75° C., whereby water is substantially removed from the composition. 
 
     
     
         2 . The method of  claim 1 , wherein the separation system is a single-tower separation system. 
     
     
         3 . The method of  claim 2 , wherein the single-tower separation system comprises a lower section and an upper section, and wherein the composition is introduced into the lower section. 
     
     
         4 . The method of  claim 3 , further comprising heating the composition. 
     
     
         5 . The method of  claim 1 , wherein the composition is heated using steam. 
     
     
         6 . The method of  claim 4 , wherein the heating of the composition comprises the steps of:
 reducing the pressure of the separation system by using a vacuum system;   maintaining the temperatures of the lower section at about 25-45° C., whereby methanol is substantially removed from the 5 composition; and   maintaining the temperatures of the lower section at about 45-75° C., whereby water is substantially removed from the composition.   
     
     
         7 . The method of  claim 1 , further comprising the step of:
 maintaining the temperatures of the lower section at about 60-95° C., whereby DMF is substantially removed from the composition.   
     
     
         8 . The method of  claim 1 , wherein the substantially pure DMF comprises at least about 98-99% DMF. 
     
     
         9 . A method for isolating DMF from a composition comprising DMF, water, and methanol, comprising:
 providing a single-tower separation system comprises a lower section and an upper section;   introducing a composition comprising DMF, water, and methanol into the lower section of the single-tower separation system;   reducing the pressure of the separation system by using a vacuum system;   maintaining the temperatures of the lower section at about 25-45° C., whereby methanol is substantially removed from the composition;   maintaining the temperatures of the lower section at about 45-75° C., whereby water is substantially removed from the composition; and   maintaining the temperatures of the lower section at about 60-95° C., whereby DMF is substantially removed from the composition to produce a substantially pure DMF composition.   
     
     
         10 . The method of  claim 9 , wherein the temperature of the lower section is adjusted by using steam. 
     
     
         11 . The method of  claim 9 , wherein the substantially pure DMF composition comprises at least about 98% DMF. 
     
     
         12 . The method of  claim 9 , wherein the substantially pure DMF composition comprises at least about 99% DMF. 
     
     
         13 . The method of  claim 9 , wherein the composition is dried by using a dehydration agent. 
     
     
         14 . A method of preparing a composition comprising anhydrous sucrose, comprising:
 applying a sucrose composition into a DMF composition, whereby a sucrose-DMF composition is produced, and wherein both the sucrose composition and the DMF composition comprise water; and   drying the sucrose-DMF composition.   
     
     
         15 . The method of  claim 14 , wherein the DMF composition comprises at least about 98% DMF. 
     
     
         16 . The method of  claim 14 , wherein the sucrose-DMF composition is dried by using a dehydration agent. 
     
     
         17 . A single-tower separation system for isolating DMF from a composition comprising DMF, water, and methanol, wherein:
 the single-tower separation system comprises an inlet, an outlet, a lower section, an upper section, and optionally, a cooling system, a separation unit, a feedback conduit, and a storage tank;   the inlet allows the introduction of the composition comprising DMF, water, and methanol into the lower section; and   the outlet allows the removal of water, methanol, and the recovery of DMF.