Process

Abstract

A process for making a 2-alkylbenzisothiazolinone which comprises reacting a bisamide of formula in water or an organic liquid containing water with a bisulphite or bisulphite release agent to form a Bunte salt and converting the Bunte salt under alkaline conditions to 2-alkyl-BIT. R is alkyl. Preferred substituents R are butyl, hexyl, 2-ethylbutyl and 2-ethylhexyl.

1 . A process for making BIT of formula 1  
       
         
           
           
               
               
           
         
         which comprises reacting a bisamide of formula 2 
         
           
             
             
                 
                 
             
           
         
         in water or an organic liquid containing water with a bisulphite or bisulphite-release agent or mixture thereof  
         wherein  
         R is hydrogen, cycloalkyl, alkyl, alkyl substituted by hydroxy, halogen, C 1-6 -alkoxy, carboxy, carbonamide, sulphonamide, nitrile or aryl or optionally substituted aryl;  
         X is halogen, nitro, alkoxy or nitrile; and 
 n is 0to 4:  
 
       
     
     
         2 . A process as claimed in  claim 1  wherein n is zero.  
     
     
         3 . A process as claimed in either  claim 1  or  claim 2  wherein R is C 1-12 -alkyl optionally substituted by phenyl.  
     
     
         4 . A process as claimed in  claim 3  wherein R is methyl, n-butyl, n-hexyl, n-octyl, 2-ethylbutyl, 2-ethyl-hexyl, i-hexyl or 2-ethylphenyl.  
     
     
         5 . A process as claimed in any one of  claims 1  to  4  wherein the bisulphite-release agent is metabisulphite.  
     
     
         6 . A process as claimed in any one of  claims 1  to  5  wherein the bisulphite or bisulphite-release agent is a solid.  
     
     
         7 . A process as claimed in any one of  claims 1  to  6  wherein the organic liquid is hydrophilic.  
     
     
         8 . A process as claimed in  claim 7  wherein the organic liquid is methanol.  
     
     
         9 . A process for making BIT of formula 1  
       
         
           
           
               
               
           
         
         which comprises reacting a polysulphide of formula 4;  
         
           
             
             
                 
                 
             
           
         
         or a bisamide of formula 2 containing a polysulphide of formula 4 in water or an organic liquid containing water with bisulphite or bisulphite-release agent or mixture thereof;  
         wherein  
         R,X and n are as defined in  claim 1;  and  
         p is 1 or 2.  
       
     
     
         10 . A process for making BIT of formula 1  
       
         
           
           
               
               
           
         
       
       which comprises treating a mixture of BIT of formula 1 and bisamide of formula 5  
       
         
           
           
               
               
           
         
       
       wherein 
 X,R and n are as defined in  claim 1;  and  
 q is 0, 1 or 2  
 in water or an organic liquid containing water with bisulphite or bisulphite-release agent or a mixture thereof.  
 
     
     
         11 . The use of BIT made by any of the processes as claimed in any one of  claims 1  to  10  as an industrial biocide.  
     
     
         12 . The use of BIT as claimed in  claim 11  as a paint-film fungicide or fungicide for plastics materials.