Method for mitigating the formation of by-products during the production of haloalkane compounds
View Patent ↗Disclosed is a process for the manufacture of haloalkane compounds, and more particularly, an improved process for the manufacture of the compound 1,1,1,3,3-penta-chloropropane (HCC-240fa), which mitigates the formation of by-products from vinyl chloride (CH 2 ═CHCl). The present invention is also useful in the manufacture of other haloalkane compounds such as HCC-250 and HCC-360. One embodiment of the invention comprises a method for mitigating 1,1,3,3,5,5-hexachloropentane and 1,1,1,3,5,5-hexachloropentane formation in the HCC-240fa manufacturing process, in which FeCl 3 , is introduced to a reactor only after the start-up phase has ended and a continuous operation has started. In a preferred embodiment, “pre-chelated” FeCl 3 , which is concentrated in a catalyst recovery column, is introduced to reactor after the continuous operation has started.
1. A process for the manufacture of haloalkane compounds consisting essentially of reacting carbon tetrachloride and an alkene wherein CCl 4 originating by-products are minimized during the start-up phase of the reaction comprising the step of conducting the reaction with only an iron metal catalyst and one or more organophosphate compounds as a co-catalyst;
wherein the alkene is selected from the group consisting of vinyl chloride, ethylene and 2-chloropropene;
wherein the haloalkane compounds are selected from the group consisting of HCC-240fa, HCC-250 and HCC-360;
wherein the CCl 4 byproducts being minimized include hexachloroethane, tetrachloroethene, chloroform, and hexachlorobutadiene, normally generated during the reaction of CCl 4 and the alkene; and wherein once the reaction contains at least about 35 wt % of the haloalkane compound, further including a step in which FeCl 3 is introduced to the reactor to prevent the formation of undesirable by-products including 1,1,3,3,5,5-hexachloropentane and 1,1,1,3,5,5-hexachloropentane.
2. The process of claim 1 , wherein the iron catalyst has a form selected from the group consisting of iron powder, iron balls, iron wire, iron shavings, and mixtures thereof.
3. The process of claim 1 , wherein the organophosphate co-catalyst is selected from the group consisting of tributylphosphate, trimethylphosphate, triethylphosphate, tripropylphosphate, triphenylphosphate and mixtures of two or more of these.
4. The process of claim 1 , which is conducted as a continuous operation.
5. The process of claim 1 , which is conducted as a batch operation.
6. A process for manufacturing 1,1,1,3,3-pentachloropropane, which consists essentially of:
(a) producing a product mixture by reacting carbon tetrachloride and vinyl chloride in the presence of a catalyst mixture consisting of iron metal and tributylphosphate under conditions sufficient to produce HCC-240fa while minimizing the formation of CCl 4 originating by-products,
(b) once the reaction in step (a) contains at least about 35 wt % of HCC-240fa, continuing the process by producing a product stream in a continuous operation by reacting carbon tetrachloride and vinyl chloride in the presence of a catalyst mixture consisting essentially of iron metal, FeCl 3 , and tributylphosphate under conditions sufficient to produce HCC-240fa while minimizing the formation of vinyl chloride originating by-products, and
(c) recovering HCC-240fa from said product stream of step (b).
7. The process of claim 6 , wherein the mole ratio of iron metal to tributylphosphate ranges from about 0.05:1 to about 500:1.
8. The process of claim 6 , wherein the mole ratio of iron metal to tributylphosphate ranges from about 10:1 to about 100:1.
9. The process of claim 6 , wherein the mole ratio of iron metal to tributylphosphate ranges from about 1.5:1 to about 10:1.
10. The process of claim 6 , wherein the concentration of the catalyst in the reaction mixture ranges from about 0.001 to about 20 weight percent.
11. The process of claim 6 , wherein the concentration of the catalyst in the reaction mixture ranges from about 0.01 to about 10 weight percent.
12. The process of claim 6 , wherein the concentration of the catalyst in the reaction mixture ranges from about 0.1 to about 5 weight percent.
13. The process of claim 6 , wherein the mole ratio of CCl 4 to VCM ranges from about 0.02:1 to about 50:1.
14. The process of claim 6 , wherein the mole ratio of CCl 4 to VCM ranges from about 0.1:1 to about 4:1.
15. The process of claim 6 , wherein the mole ratio of CCl 4 to VCM ranges from about 1:1 to about 3:1.
16. The process of claim 6 , wherein step (c) further comprises the steps of removing the iron metal from the catalyst mixture, followed by the flash-distilling of the HCC-240fa product stream to separate the HCC-240fa, unreacted CCl 4 and unreacted VCM from catalyst mixture, and recycling the remaining catalyst components to step (a).
17. The process of claim 6 , wherein the iron catalyst has a form selected from the group consisting of iron powder, iron balls, iron wire, iron shavings, and mixtures thereof.
18. The process of claim 17 , wherein the iron powder comprises a fine powder of pure metallic iron.
19. The process of claim 18 , wherein the iron powder has a particle size smaller than 325 mesh.
20. The process of claim 18 , wherein the iron powder is added to the reactor by powder slurry in carbon tetrachloride.
21. The process of claim 18 , wherein the iron powder is added to the reactor by powder slurry in TBP.
22. The process of claim 18 , wherein the iron powder is added to the reactor by powder slurry in a mixture of CCl 4 and tributylphosphate.
23. The process of claim 6 , wherein the organophosphate co-catalyst is selected from the group consisting of tributylphosphate, trimethylphosphate, triethylphosphate, tripropylphosphate, triphenylphosphate, and mixtures of two or more of these.
24. The process of claim 6 , wherein step (a) is conducted as a batch operation, and step (b) is conducted as a continuous operation which includes the use of FeCl 3 .
25. The process of claim 24 , wherein the FeCl 3 is selected from the group consisting of solid FeCl 3 , a solution of FeCl 3 , and a suspension of FeCl 3 .
26. The process of claim 24 , wherein the FeCl 3 comprises pre-chelated FeCl 3 .
27. A process for the manufacture of haloalkane compounds from carbon tetrachloride and an alkene consisting of the steps of:
(a) reacting CCl 4 with an alkene in the presence of an iron metal catalyst and one or more organophosphate compounds as a co-catalyst; and
(b) once the reaction in step (a) contains at least about 40 wt % of the haloalkane, continuing the process by reacting CCl 4 with an alkene in the presence of FeCl 3 and iron metal as a catalyst system and one or more organophosphate compounds as a co-catalyst.
28. A process for the manufacture of haloalkane compounds consisting essentially of reacting carbon tetrachloride and an alkene wherein CCl 4 originating by-products are minimized during the start-up phase of the reaction including the step of starting the reaction with only an iron metal catalyst and one or more organophosphate compounds as a co-catalyst;
wherein the alkene is selected from the group consisting of vinyl chloride, ethylene and 2-chloropropene;
wherein the haloalkane compounds are selected from the group consisting of HCC-240fa, HCC-250 and HCC-360; and
wherein once initial the reaction contains greater than about 50 wt % of haloalkane, the reaction further including a step in which FeCl 3 is introduced to the reactor, such that the formation of the undesired by-product 1,1,3,3,5,5-hexachloropentane is suppressed to about 5% or less.
29. The process of claim 28 , wherein the haloalkane is HCC-240fa.
30. The process of claim 28 , wherein the haloalkane is HCC-250.
31. The process of claim 28 , wherein the haloalkane is HCC-360.