Process for preparing a chlorinated alkene

Abstract

Disclosed is a process for preparing a chlorinated alkene, comprising contacting a chlorinated alkane with a catalyst in a dehydrochlorination zone to produce a liquid reaction mixture comprising the chlorinated alkane and the chlorinated alkene, and extracting chlorinated alkene from the reaction mixture, wherein the concentration of the chlorinated alkene in the reaction mixture present in the dehydrochlorination zone is controlled such that the molar ratio of chlorinated alkene:chlorinated alkane is from 1:99 to 50:50.

1 . A process for preparing a chlorinated alkene comprising contacting a chlorinated alkane with a catalyst in a dehydrochlorination zone to produce a liquid reaction mixture comprising the chlorinated alkane and the chlorinated alkene, and extracting chlorinated alkene from the reaction mixture, wherein the concentration of the chlorinated alkene in the reaction mixture present in the dehydrochlorination zone is controlled such that the molar ratio of chlorinated alkene:chlorinated alkane is from 1:99 to 50:50. 
     
     
         2 . The process of  claim 1 , wherein the molar ratio of chlorinated alkene:chlorinated alkane in the reaction mixture is from 5:95 to 50:50. 
     
     
         3 . The process of  claim 1  or  claim 2 , wherein the molar ratio of chlorinated alkene:chlorinated alkane in the reaction mixture is from 5:95 to 30:70. 
     
     
         4 . The process of any one of  claims 1  to  4 , wherein the chlorinated alkane contacted with the catalyst in the dehydrochlorination zone has a purity of about 98.5% or higher. 
     
     
         5 . The process of any one of  claims 1  to  4 , wherein the chlorinated alkene is extracted from the reaction mixture on a continuous basis. 
     
     
         6 . The process of any one of  claims 1  to  5 , wherein extraction of the chlorinated alkene from the reaction mixture is achieved by distillation. 
     
     
         7 . The process of any one of  claims 1  to  6 , wherein the chlorinated alkene is condensed from a gaseous mixture comprising the chlorinated alkene generated in the dehydrochlorination zone. 
     
     
         8 . The process of  claim 7 , wherein the distillation is performed in distillation apparatus in fluid communication with the dehydrochlorination zone. 
     
     
         9 . The process of  claim 8 , wherein the distillation apparatus is coupled to the dehydrochlorination zone. 
     
     
         10 . The process of any one of  claims 1  to  9  where liquid reaction mixture is extracted from the dehydrochlorination zone and subjected to distillation using apparatus remote from the dehydrochlorination zone. 
     
     
         11 . The process of any one of  claims 6  to  10 , wherein the distillate comprises gaseous hydrochloric acid as an impurity which is extracted therefrom. 
     
     
         12 . The process of any one of  claims 1  to  11 , wherein the operating temperature in the dehydrochlorination zone is about 70° C. to about 250° C. 
     
     
         13 . The process of any one of  claims 1  to  12 , wherein the operating temperature in the dehydrochlorination zone is about 120° C. to about 170° C. 
     
     
         14 . The process of any one of  claims 1  to  13 , further comprising contacting a mixture comprising chlorinated alkene, catalyst and chlorinated alkane starting material with an aqueous medium in an aqueous treatment zone. 
     
     
         15 . A process for removing oxygenated impurities from a mixture comprising a chlorinated alkene, oxygenated impurities and optionally a catalyst and/or a chlorinated alkane, comprising contacting the mixture with an aqueous medium to form a biphasic mixture and extracting the organic phase from that biphasic mixture. 
     
     
         16 . The process of  claim 15  wherein the mixture comprises the mixture extracted from the dehydrochlorination zone in the process of  claim 15 . 
     
     
         17 . The process of any one of  claims 13  to  16 , wherein the pH of the mixture in the aqueous treatment zone, following the addition of acid, is about 4 or lower. 
     
     
         18 . The process of any one of  claims 13  to  17 , wherein the mixture is contacted with a haloalkane extraction agent. 
     
     
         19 . The process according to any one of  claims 13  to  18 , wherein a biphasic mixture is formed in the aqueous treatment zone and an organic phase comprising chlorinated alkane and chlorinated alkene is extracted from the biphasic mixture. 
     
     
         20 . The process according to  claim 19 , wherein chlorinated alkene is extracted from the organic phase. 
     
     
         21 . The process according to any one of  claims 1  to  20 , wherein the catalyst comprises metallic iron, ferrous chloride and/or ferric chloride. 
     
     
         22 . The process according to any one of  claims 1  to  21 , wherein the chlorinated alkene is 1,1,3-trichloropropene. 
     
     
         23 . The process according to any one of  claims 1  to  22  wherein the chlorinated alkane is 1,1,1,3-tetrachloropropane. 
     
     
         24 . The process of any one of  claims 1  to  23 , wherein all surfaces of the apparatus in which the process is carried out with which any chlorinated alkene-containing mixture will contact during use of that apparatus have an iron content of about 20% or less, about 10% or less or about 5% or less, and/or are formed from non-metallic materials, for example enamel, glass, impregnated graphite (e.g. impregnated with phenolic resin), silicium carbide and/or plastics materials such as polytetrafluoroethylene, perfluoroalkoxy and/or polyvinylidene fluoride. 
     
     
         25 . A chlorinated alkene composition obtainable from the process of any one of  claims 1  to  24 . 
     
     
         26 . The composition of  claim 25  which comprises:
 about 95% or more, about 97% or more, about 99% or more, about 99.2% or more about 99.5% or more or about 99.7% or more of the chlorinated alkene, 
 less than about 50000 ppm, less than about 20000 ppm, less than about 10000 ppm, less than about 5000 ppm, less than about 2000 ppm, less than about 1000 ppm, less than about 500 ppm, less than about 200 ppm, or less than about 100 ppm of chlorinated alkane starting material, 
 less than about 1000 ppm, less than about 500 ppm, less than about 200 ppm, or less than about 100 ppm of chlorinated C 5-6  alkane impurities, 
 less than about 1000 ppm, less than about 500 ppm, less than about 200 ppm, or less than about 100 ppm of chlorinated alkene impurities (i.e. chlorinated alkenes other than the compound of interest), 
 less than about 1000 ppm, less than about 500 ppm, less than about 250 ppm, or less than about 100 ppm of oxygenated organic compounds, 
 less than about 500 ppm, about 250 ppm or less, about 100 ppm or less or about 50 ppm or less of water, and/or 
 less than about 500 ppm, less than about 200 ppm, less than about 100 ppm, less than about 50 ppm, less than about 20 ppm, less than about 10 ppm or less than about 5 ppm metal. 
 
     
     
         27 . A chlorinated alkene composition which comprises:
 about 95% or more, about 97% or more, about 99% or more, about 99.2% or more about 99.5% or more or about 99.7% or more of the chlorinated alkene,   less than about 50000 ppm, less than about 20000 ppm, less than about 10000 ppm, less than about 5000 ppm, less than about 2000 ppm, less than about 1000 ppm, less than about 500 ppm, less than about 200 ppm, or less than about 100 ppm of chlorinated alkane starting material,   less than about 1000 ppm, less than about 500 ppm, less than about 200 ppm, or less than about 100 ppm of chlorinated C 5-6  alkane impurities,   less than about 1000 ppm, less than about 500 ppm, less than about 200 ppm, or less than about 100 ppm of chlorinated alkene impurities (i.e. chlorinated alkenes other than the compound of interest)   less than about 1000 ppm, less than about 500 ppm, less than about 250 ppm, or less than about 100 ppm of oxygenated organic compounds,   less than about 500 ppm, about 250 ppm or less, about 100 ppm or less or about 50 ppm or less of water, and/or   less than about 500 ppm, less than about 200 ppm, less than about 100 ppm, less than about 50 ppm, less than about 20 ppm, less than about 10 ppm or less than about 5 ppm metal.   
     
     
         28 . The composition of  claims 25  to  27 , wherein the chlorinated alkene is 1,1,3-trichloropropene. 
     
     
         29 . The composition of  claim 28 , comprising less than about 1000 ppm, less than about 500 ppm, less than about 200 ppm, or less than about 100 ppm of 3,3,3-trichloropropene. 
     
     
         30 . Use of the composition of any one of  claims 25  to  29  as a feedstock in the synthesis of a halogenated alkene or halogenated alkane. 
     
     
         31 . The use of  claim 30 , wherein the halogenated alkene or halogenated alkane is a fluorinated or chlorinated alkene or a fluorinated or chlorinated alkane.