Process for stabilization of dry cleaning solutions

Abstract

A method for stabilizing silicone dry cleaning solvents containing impurities, comprising contacting the silicone solvent with an adsorbent, neutralizing agent or combination thereof to purify the solvent and prevent reequilibration and polymerization, and separating the silicone solvent.

1 . A method for stabilizing silicone dry cleaning solvents that may contain an undesirable basic impurity capable of causing cyclic siloxane formation comprising, contacting the silicone dry cleaning solvent with an adsorbent, neutralizing agent, or combination thereof, and separating the silicone solvent from the adsorbent.  
     
     
         2 . The method of  claim 1 , wherein the amount of adsorbent, neutralizing agent, or combination thereof used is up to 100 parts by weight per 100 parts by weight of silicone solvent.  
     
     
         3 . The method of  claim 1 , wherein the contact time with the adsorbent is from about 0.001 to about 6 hours.  
     
     
         4 . The method of  claim 1 , wherein the temperature is from about 10° C. to about 80° C.  
     
     
         5 . The method of  claim 1 , wherein the adsorbent used is selected from the group consisting of granular activated carbon, silica gel, acid clay, fullers earth, diatomaceous earth, 4A molecular sieves, 13X molecular sieves, powdered decolorizing charcoal.  
     
     
         6 . The method of  claim 5 , wherein the adsorbent used is 4A molecular sieves, 13X molecular sieves, powdered decolorizing charcoal or fullers earth.  
     
     
         7 . The method of  claim 1 , wherein the solvent is a linear or branched siloxane comprising one or more compounds of the structural formula: 
       M 2+y+2z D x T y Q z   
       wherein: 
 M is R 1   3 SiO 1/2 ;  
 D is R 2   2 SiO 2/2 ;  
 T is R 3 SiO 3/2 ;  
 and  
 Q is SiO 4/2    
 R 1 , R 2  and R 3  are each independently a monovalent hydrocarbon radical; and  
 x and y are each integers, wherein 0≦x≦10 and 0≦y≦10 and 0≦z≦10.  
 
     
     
         8 . The method of  claim 7 , wherein the linear or branched, volatile siloxane of the present invention comprises octamethyltrisiloxane, decamethyltetrasiloxane, or dodecamethylpentasiloxane or methyltris(trimethylsiloxy)silane.  
     
     
         9 . The method of  claim 1 , wherein the silicone is a cyclic siloxane comprising one or more compounds of the structural formula:  
       
         
           
           
               
               
           
         
       
       wherein: 
 R 5 , R 6 , R 7  and R 8  are each independently a monovalent hydrocarbon group; and  
 a and b are each integers wherein 0≦a≦10 and 0≦b≦10, provided that 3≦(a+b)≦10.  
 
     
     
         10 . The method of  claim 9 , wherein the cyclic siloxane is octamethylcyclotetrasiloxane or decamethylcyclopentasiloxane.  
     
     
         11 . The method of  claim 1 , wherein the impurities removed are potassium silanolate, potassium hydroxide, tetramethylammonium hydroxide, or a combination thereof.  
     
     
         12 . A silicone dry cleaning fluid treated by the method of  claim 1 .  
     
     
         13 . An adsorbent used in the method of  claim 1 , wherein the adsorbent comprises the impurities selected from potassium silanolate, potassium hydroxide, tetramethylammonium hydroxide, or a combination thereof.  
     
     
         14 . A dry cleaning process comprising: 
 (1) cleaning an article by the steps of: 
 (a) contacting the article with a silicone solvent; and  
 (b) removing the silicone solvent; and  
   (2) treating the silicone solvent that has been removed by the steps of: 
 (a) contacting the silicone solvent with an adsorbent, neutralizing agent, or combination thereof; and  
 (b) separating the silicone solvent from the adsorbent.  
   
     
     
         15 . The process of  claim 14 , further comprising reusing the treated silicone solvent in step (1).