Acesulfame Potassium Compositions and Processes for Producing Same

Abstract

Improved processes for producing high purity acesulfame potassium. In one embodiment, the process comprises the steps of contacting a solvent, e.g., dichloromethane, and a cyclizing agent, e.g., sulfur trioxide, to form a cyclizing agent composition and reacting an acetoacetamide salt with the cyclizing agent in the composition to form a cyclic sulfur trioxide adduct. The contact time is less than 60 minutes. The process also comprises forming from the cyclic sulfur trioxide adduct composition a finished acesulfame potassium composition comprising non-chlorinated, e.g., non-chlorinated, acesulfame potassium and less than 35 wppm 5-halo acesulfame potassium, preferably less than 5 wppm.

We claim: 
     
         1 . A process for producing a finished acesulfame potassium composition, the process comprising the steps of:
 (a) contacting a solvent and a cyclizing agent to form a cyclizing agent composition;   (b) reacting an acetoacetamide salt with the cyclizing agent in the cyclizing agent composition to form a cyclic sulfur trioxide adduct; and   (c) forming from the cyclic sulfur trioxide adduct the finished acesulfame potassium composition comprising non-chlorinated acesulfame potassium and less than 35 wppm 5-chloro-acesulfame potassium;   wherein contact time from the beginning of step (a) to the beginning of step (b) is less than 60 minutes.   
     
     
         2 . The process of  claim 1 , wherein the forming comprises:
 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 non-chlorinated acesulfame potassium and less than 35 wppm 5-chloro-acesulfame potassium; and
 forming the finished acesulfame potassium composition from the crude acesulfame potassium composition. 
   
     
     
         3 . The process of  claim 2 , wherein the finished acesulfame potassium composition comprises from 0.001 wppm to 5 wppm 5-chloro-acesulfame potassium. 
     
     
         4 . The process of  claim 2 , wherein the contact time is less than 15 minutes and the crude acesulfame potassium composition comprises from 0.001 wppm to 5 wppm 5-chloro-acesulfame potassium and the finished acesulfame potassium composition comprises from 0.001 wppm to 5 wppm 5-chloro-acesulfame potassium. 
     
     
         5 . The process of  claim 2 , wherein the contact time is less than 5 minutes and the crude acesulfame potassium composition comprises from 0.001 wppm to 5 wppm 5-chloro-acesulfame potassium and the finished acesulfame potassium composition comprises from 0.001 wppm to 2.7 wppm 5-chloro-acesulfame potassium. 
     
     
         6 . The process of  claim 2 , wherein the crude acesulfame potassium composition comprises less than 35 wppm 5-chloro-acesulfame potassium. 
     
     
         7 . The process of  claim 5 , wherein the finished acesulfame potassium composition comprises at least 90% by weight of the 5-chloro-acesulfame potassium present in the crude acesulfame potassium composition. 
     
     
         8 . The process of  claim 2 , wherein the hydrolyzing comprises adding water to the cyclic sulfur trioxide adduct to form a hydrolysis reaction mixture, and wherein the temperature of the hydrolysis reaction mixture is maintained at a temperature ranging from −35° C. to 0° C. 
     
     
         9 . The process of  claim 8 , wherein the finished acesulfame potassium composition comprises from 0.001 wppm to 5 wppm organic impurities. 
     
     
         10 . The process of  claim 1 , further comprising:
 reacting sulfamic acid and an amine to form an amidosulfamic acid salt; and   reacting the amidosulfamic acid salt and acetoacetylating agent to form the acetoacetamide salt.   
     
     
         11 . The process of  claim 1 , wherein the finished acesulfame potassium composition comprises from 0.001 wppm to 2.7 wppm 5-chloro-acesulfame potassium. 
     
     
         12 . The process of  claim 1 , wherein the finished acesulfame potassium composition comprises from 0.001 wppm to 5 wppm organic impurities. 
     
     
         13 . The process of  claim 1 , wherein the finished acesulfame potassium composition comprises from 0.001 wppm to 5 wppm heavy metals. 
     
     
         14 . The process of  claim 1 , wherein the cyclizing agent composition comprises less than 1 wt % of compounds selected from chloromethyl chlorosulfate, methyl-bis-chlorosulfate, and mixtures thereof. 
     
     
         15 . The process of  claim 1 , wherein the reacting is conducted for a cyclization reaction time, from the start of the reactant feed to the end of the reactant feed, less than 35 minutes. 
     
     
         16 . The process of  claim 1 , wherein the weight ratio of solvent to cyclizing agent in the cyclizing agent composition is at least 1:1. 
     
     
         17 . The process of  claim 1 , further comprising cooling the cyclizing agent composition to a temperature less than 15° C. 
     
     
         18 . The process of  claim 1 , wherein the cyclizing agent comprises sulfur trioxide and the solvent comprises dichloromethane. 
     
     
         19 . A finished acesulfame potassium composition produced from the process of  claim 1 . 
     
     
         20 . The finished acesulfame potassium composition of  claim 19 , comprising:
 non-chlorinated acesulfame potassium;   from 0.001 wppm to 2.7 wppm 5-chloro acesulfame potassium; and   from 0.001 wppm to 5 wppm heavy metals.   
     
     
         21 . A process for producing a finished acesulfame potassium composition, the process comprising the steps of:
 reacting sulfamic acid and triethylamine to form an amidosulfamic acid salt;   reacting the amidosulfamic acid salt and diketene to form the acetoacetamide salt;   contacting dichloromethane and a sulfur trioxide to form a cyclizing agent composition;   reacting the acetoacetamide salt with the sulfur trioxide in the cyclizing agent composition to form a cyclic sulfur trioxide adduct;
 hydrolyzing the cyclic sulfur trioxide adduct to form an acesulfame-H composition; and neutralizing the acesulfame-H in the acesulfame-H composition to form crude acesulfame potassium composition comprising non-chlorinated acesulfame potassium and less than 35 wppm 5-chloro-acesulfame potassium; and
 forming from crude acesulfame potassium composition the finished acesulfame potassium composition comprising non-chlorinated acesulfame potassium and less than 10 wppm 5-chloro-acesulfame potassium, 
 wherein contact time from the beginning of step (a) to the beginning of step (b) is less than 10 minutes. 
 
   
     
     
         22 . The process of  claim 21 , further comprising cooling the cyclizing agent composition to a temperature less than 15° C. 
     
     
         23 . An acesulfame potassium composition comprising non-chlorinated acesulfame potassium and less than 35 wppm 5-chloro-acesulfame potassium. 
     
     
         24 . The acesulfame potassium composition of  claim 23 , further comprising less than 37 wppm acetoacetamide-N-sulfonic acid. 
     
     
         25 . The acesulfame potassium composition of  claim 23 , further comprising 0.001 wppm to 5 wppm organic impurities and/or 0.001 wppm to 5 wppm of at least one heavy metal. 
     
     
         26 . The acesulfame potassium composition of  claim 25 , wherein the at least one heavy metal is selected from the group consisting of mercury, lead and mixtures thereof. 
     
     
         27 . The acesulfame potassium composition of  claim 26 , wherein the mercury is present in an amount of 1 wppb to 20 wppm. 
     
     
         28 . The acesulfame potassium composition of  claim 26 , wherein the lead is present in an amount of 1 wppb to 25 wppm.