Synthesis of 1,1,2,3-tetrachloropropene

1. In a method for producing 1,1,2,3-tetrachloropropene (HCC-1230xa), which includes the following steps:

(1) preparing 1,1,1,3-tetrachloropropane by reacting ethylene with carbon tetrachloride in the presence of both a source of metallic iron that is effective as an activator for the reaction, and a promoter for the reaction, said promoter being selected from phosphorus (V) compounds containing a phosphoryl group;

(2) dehydrochlorinating the 1,1,1,3-tetrachloropropane to produce a mixture of 1,1,3- and 3,3,3-trichloropropenes;

(3) chlorinating at least one of the trichloropropenes obtained by the dehydrochlorination step to produce 1,1,1,2,3-pentachloropropane;

(4) dehydrochlorinating the 1,1,1,2,3-pentachloropropane to produce a mixture of 1,1,2,3- and 2,3,3,3-tetrachloropropenes; and

(5) contacting the mixture of tetrachloropropenes with anhydrous ferric chloride acting as an allylic rearrangement catalyst, thereby converting the 2,3,3,3-tetrachloropropene to 1,1,2,3-tetrachloropropene;

the improvement comprising;

using a first reactive distillation column for HCC-250fb dehydrochlorination, and a second reactive distillation column for HCC-240db dehydrochlorination/HCC-1230xf isomerization.

2. The process of claim 1 , wherein Step (1) is conducted in the liquid phase in the presence of a catalyst system comprising iron, ferric chloride and a promoter comprising one or more chelating agents.

3. The process of claim 2 , wherein Step (1) is modified such that the crude reaction material is fed directly to a reactive distillation unit containing an effective amount of a dehydrochlorination catalyst.

4. The process of claim 2 , wherein the dehydrochlorination catalyst can either exist within column internals (packing or trays) and/or be added to the reboiler or column sump.

5. The process of claim 3 , wherein the dehydrochlorination catalyst comprises one or more metal halides.

6. In a method for producing 1,1,2,3-tetrachloropropene (HCC-1230xa), which includes the following steps:

(1) preparing 1,1,1,3-tetrachloropropane by reacting ethylene with carbon tetrachloride in the presence of both a source of metallic iron that is effective as an activator for the reaction, and a promoter for the reaction, said promoter being selected from trialkyl phosphates or trialkyl phosphites;

(2) dehydrochlorinating the 1,1,1,3-tetrachloropropane to produce a mixture of 1,1,3- and 3,3,3-trichloropropenes;

(3) chlorinating at least one of the trichloropropenes obtained by the dehydrochlorination step to produce 1,1,1,2,3-pentachloropropane;

(4) dehydrochlorinating the 1,1,1,2,3-pentachloropropane to produce a mixture of 1,1,2,3- and 2,3,3,3-tetrachloropropenes; and

(5) contacting the mixture of tetrachloropropenes with anhydrous ferric chloride acting as an allylic rearrangement catalyst, thereby converting the 2,3,3,3-tetrachloropropene to 1,1,2,3-tetrachloropropene;

the improvement comprising;

using a first reactive distillation column for HCC-250fb dehydrochlorination, and a second reactive distillation column for HCC-240db dehydrochlorination/HCC-1230xf isomerization.

7. The process of claim 6 , wherein Step (4) takes place in a liquid phase reactor in the presence of caustic solution or a dehydrochlorination catalyst.

8. The process of claim 6 , wherein Step (5) takes place in a liquid phase reactor in the presence of an isomerization catalyst.

9. In a method for producing 1,1,2,3-tetrachloropropene (HCC-1230xa), which includes the following steps:

(1) preparing 1,1,1,3-tetrachloropropane by reacting ethylene with carbon tetrachloride in the presence of both a source of metallic iron that is effective as an activator for the reaction, and a promoter for the reaction, said promoter being selected from trialkyl phosphates;

(2) dehydrochlorinating the 1,1,1,3-tetrachloropropane to produce a mixture of 1,1,3- and 3,3,3-trichloropropenes;

(3) chlorinating at least one of the trichloropropenes obtained by the dehydrochlorination step to produce 1,1,1,2,3-pentachloropropane;

(4) dehydrochlorinating the 1,1,1,2,3-pentachloropropane to produce a mixture of 1,1,2,3- and 2,3,3,3-tetrachloropropenes; and

(5) contacting the mixture of tetrachloropropenes with anhydrous ferric chloride acting as an allylic rearrangement catalyst, thereby converting the 2,3,3,3-tetrachloropropene to 1,1,2,3-tetrachloropropene;

the improvement comprising;

combining the process of Step (1) with the process of Step (2) such that the crude product formed in Step (1) the dehydrochlorination process of Step (2) are combined in a single reactive column; and

combining the dehydrochlorination reaction of Step (4) with the process of Step (5) in a single reactive column.

10. The process of claim 9 , wherein Step (1) is conducted in the liquid phase in the presence of a catalyst system comprising iron, ferric chloride and a chelating agent.

11. The process of claim 10 , wherein Step (1) is modified such that the crude reaction material is fed directly to a reactive distillation unit containing an effective amount of a dehydrochlorination catalyst.

12. The process of claim 10 , wherein the dehydrochlorination catalyst can either exist within column internals (packing or trays) and/or be added to the reboiler or column sump.

13. The process of claim 11 , wherein the dehydrochlorination catalyst comprises one or more metal halides.

14. The process of claim 9 , wherein Step (4) takes place in a liquid phase reactor in the presence of caustic solution or a dehydrochlorination catalyst.

15. The process of claim 9 , wherein Step (5) takes place in a liquid phase reactor in the presence of an isomerization catalyst.