Acesulfame Potassium Compositions and Processes for Producing Same

Abstract

Compositions and processes for producing high purity acesulfame potassium are described. One process comprises the steps of forming a cyclic sulfur trioxide adduct; hydrolyzing the cyclic sulfur trioxide adduct to form an acesulfame-H composition comprising acesulfame-H; neutralizing the acesulfame-H in the acesulfame-H composition to form a crude acesulfame potassium composition comprising acesulfame potassium and less than 2800 wppm acetoacetamide-N-sulfonic acid, wherein the neutralizing step is conducted or maintained at a pH at or below 11.0; and treating the crude acesulfame potassium composition to form the finished acesulfame potassium composition comprising acesulfame potassium and less than 37 wppm acetoacetamide-N-sulfonic acid.

We claim: 
     
         1 . A process for producing a finished acesulfame potassium composition, the process comprising the steps of:
 (a) forming a cyclic sulfur trioxide adduct;   (b) hydrolyzing the cyclic sulfur trioxide adduct to form an acesulfame-H composition comprising acesulfame-H;   (c) neutralizing the acesulfame-H in the acesulfame-H composition to form a crude acesulfame potassium composition comprising acesulfame potassium and less than 2800 wppm acetoacetamide-N-sulfonic acid, wherein the neutralizing step is conducted at a pH at or below 11.0; and   (d) treating the crude acesulfame potassium composition to form the finished acesulfame potassium composition comprising acesulfame potassium and less than 37 wppm acetoacetamide-N-sulfonic acid.   
     
     
         2 . The process of  claim 1 , wherein the neutralizing step (c) comprises:
 reacting acesulfame-H with a neutralizing agent in an acesulfame-H/neutralizing agent reaction mixture to form the acesulfame potassium composition.   
     
     
         3 . The process of  claim 2 , wherein the neutralizing agent comprises potassium hydroxide. 
     
     
         4 . The process of  claim 3 , wherein the potassium hydroxide is produced via a membrane process and the finished acesulfame potassium composition comprises less than 10 wppm mercury. 
     
     
         5 . The process of  claim 2 , wherein the acesulfame-H/neutralizing agent reaction mixture comprises from 1 wt% to 95 wt% neutralizing agent and from 1 wt% to 95 wt% acesulfame-H, based on the total weight of the acesulfame-H/neutralizing agent reaction mixture. 
     
     
         6 . The process of  claim 1 , wherein the neutralizing step (c) comprises neutralizing the acesulfame-H in the acesulfame-H composition to form the crude acesulfame potassium composition further comprising acetoacetamide. 
     
     
         7 . The process of  claim 6 , wherein the crude acesulfame potassium composition comprises from 500 wppm to 2375 wppm acetoacetamide-N-sulfonic acid and the finished acesulfame potassium composition comprises less than 25 wppm acetoacetamide-N-sulfonic acid and further comprises less than 25 wppm acetoacetamide. 
     
     
         8 . The process of  claim 6 , wherein the neutralizing step (c) is conducted at a pH ranging from 9.0 to 11.0 and the crude acesulfame potassium composition comprises from 20 wppm to 2500 wppm acetoacetamide-N-sulfonic acid and the finished acesulfame potassium composition comprises less than 25 wppm acetoacetamide-N-sulfonic acid and less than 15 wppm acetoacetamide. 
     
     
         9 . The process of  claim 6 , wherein the neutralizing step (c) is conducted at a pH ranging from 8 to 10.3 and the crude acesulfame potassium composition comprises from 600 wppm to 1200 wppm acetoacetamide-N-sulfonic acid, and the finished acesulfame potassium composition comprises less than 10 wppm acetoacetamide-N-sulfonic acid and less than 10 wppm acetoacetamide. 
     
     
         10 . The process of  claim 6 , wherein the neutralizing step (c) is conducted at a pH ranging from 8 to 10.3 and the crude acesulfame potassium composition comprises less than 2400 wppm acetoacetamide-N-sulfonic acid, and the finished acesulfame potassium composition comprises less than 10 wppm acetoacetamide-N-sulfonic acid and less than 10 wppm acetoacetamide. 
     
     
         11 . The process of  claim 6 , wherein the finished acesulfame potassium composition comprises less than 37 wppm acetoacetamide. 
     
     
         12 . The process of  claim 1 , wherein the neutralizing step (c) is conducted at a pH ranging from 9.0 to 11.0. 
     
     
         13 . The process of  claim 1 , wherein the neutralizing step (c) is conducted at a pH ranging from 9.0 to 10.5. 
     
     
         14 . The process of  claim 1 , wherein the neutralizing step (c) is conducted at a pH ranging from 8.0 to 10.3. 
     
     
         15 . The process of  claim 1 , wherein the treating step (d) is conducted at a temperature below 90° C. 
     
     
         16 . The process of  claim 1 , wherein the treating step (d) comprises an evaporating step with a residence time less than 180 minutes. 
     
     
         17 . The process of  claim 1 , wherein the neutralizing step is maintained at a pH at or below 11.0. 
     
     
         18 . A finished acesulfame potassium composition produced by the process of  claim 1 . 
     
     
         19 . A process for producing a finished acesulfame potassium composition, the process comprising the steps of:
 (a) reacting sulfamic acid and triethylamine to form an amidosulfamic acid salt;   (b) reacting the amidosulfamic acid salt and diketene to form acetoacetamide salt;   (c) contacting dichloromethane and a sulfur trioxide to form a cyclizing agent composition; (d) reacting the acetoacetamide salt with sulfur trioxide in the cyclizing agent composition to form a cyclic sulfur trioxide adduct;   (e) hydrolyzing the cyclic sulfur trioxide adduct to form an acesulfame-H composition comprising acesulfame-H;   (f) neutralizing the acesulfame-H in the acesulfame-H to form a crude acesulfame potassium composition comprising acesulfame potassium and less than 2800 wppm acetoacetamide-N-sulfonic acid, wherein neutralizing step is conducted at a pH at or below 11.0,   (g) treating the crude acesulfame potassium composition to form the finished acesulfame potassium composition comprising acesulfame potassium and less than 37 wppm acetoacetamide-N-sulfonic acid,   wherein steps (a), (b), and (c) can be performed in any order before the performance of step (d).   
     
     
         20 . The process of  claim 19 , wherein the finished acesulfame potassium composition further comprises less than 20 wppm acetoacetamide. 
     
     
         21 . The process of  claim 20 , wherein the neutralizing step (f) is conducted at a pH ranging from 9.0 to 11.0 and the crude acesulfame potassium composition comprises from 20 wppm to 2500 wppm acetoacetamide-N-sulfonic acid and the finished acesulfame potassium composition comprises less than 25 wppm acetoacetamide-N-sulfonic acid and less than 15 wppm acetoacetamide. 
     
     
         22 . An acesulfame potassium composition comprising acesulfame potassium and less than 25 wppm acetoacetamide-N-sulfonic acid and less than 25 wppm acetoacetamide. 
     
     
         23 . The acesulfame potassium composition of  claim 22 , further comprising 0.001 wppm to 5 wppm organic impurities and/or 0.001 wppm to 5 wppm of at least one heavy metal. 
     
     
         24 . The acesulfame potassium composition of  claim 23 , wherein the at least one heavy metal is selected from the group consisting of mercury, lead and mixtures thereof. 
     
     
         25 . The acesulfame potassium composition of  claim 24 , wherein the mercury is present in an amount of 1 wppb to 20 wppm. 
     
     
         26 . The acesulfame potassium composition of  claim 24 , wherein the lead is present in an amount of 1 wppb to 25 wppm.