Method for capturing and recycling iron catalyst used in the production of haloalkane compounds
View Patent ↗Disclosed is a method for capturing and recycling iron catalyst used in the production of haloalkane compounds and more particularly, to an improved process for the manufacture of the compound 1,1,1,3,3-pentachloropropane (HCC-240fa), in which an electromagnetic separation unit (EMSU) is used to facilitate the reaction. When energized, the EMSU functions to remove all iron particles from the reactor effluent; when de-energized, the iron particles captured by the EMSU can be flushed back into the reactor for re-use in the continued production of HCC-240fa. The present invention is also useful in the manufacturing processes for other haloalkane compounds such as HCC-250 and HCC-360.
1. A process for the production of 1,1,1,3,3-pentachloropropane (HCC-240fa) wherein carbon tetrachloride (CCl 4 ) and vinyl chloride (VCM) are reacted with a catalytic amount of iron powder and a co-catalyst selected from tributylphosphate, triethylphosphate, trimethylphosphate, tripropylphosphate, another trialkylphosphate compound, and mixtures of two or more of these;
wherein the reaction of CCl 4 and VCM is carried out at a residence time of from about 0.01 hours to about 24 hours;
wherein one or more electromagnetic separation units (EMSUs) are used to capture suspended iron powder particles from the reaction mixture, thereby producing an iron-free reactor effluent;
wherein the iron-free reactor effluent is distilled to separate unreacted CCl 4 and/or VCM from the HCC-240 reaction product.
2. The process of claim 1 , wherein the reaction residence time is from about 1 hour to about 12 hours.
3. The process of claim 1 , wherein the distillation is a vacuum flash-distillation.
4. The process of claim 3 , wherein the flash-distillation is conducted in two steps:
first, vacuum flash-distillation is conducted to remove CCl 4 and/or VCM; and
second, another vacuum flash-distillation is conducted at a lower pressure than that used in the first step, to remove the HCC-240fa reaction product.
5. The process of claim 4 , wherein the second vacuum distillation is carried out at about 5 to about 200 mm Hg and a temperature of about 50° C. to about 150° C. to recover the HCC-240fa product.
6. The process of claim 5 , wherein the second vacuum distillation is carried out in the presence of a trialkyl phosphate.
7. The process of claim 6 , wherein the trialkyl phosphate is tributyl phosphate.
8. The process of claim 7 , wherein 5 weight percent of tributyl phosphate is used.
9. The process of claim 1 , wherein batch processing is used for the reaction.
10. The process of claim 1 , wherein a continuous manufacturing process is used for the reaction.
11. The process of claim 1 , wherein two or more tandem EMSUs are used.
12. In a process for the manufacture of the compound 1,1,1,3,3-pentachloropropane (HCC-240fa) comprising reacting carbon tetrachloride (CCl 4 ) and vinyl chloride (VCM) in the presence of a catalyst mixture comprising tributyl phosphate (TBP), metallic iron powder to produce a reaction product mixture containing HCC-240fa; and wherein the HCC-240fa product is recovered by separating it from the other reactants;
the improvement comprising:
(a) continuously feeding CCl 4 and VCM into the reactor and adding iron powder and the co-catalyst TBP into reactor either periodically or continuously;
(b) conducting the reaction of the CCl 4 and VCM at a residence time of from about 1 hour to about 12 hours, thereby forming a reaction slurry of HCC-240fa and other reaction components;
(c) continuously withdrawing slurry from the reactor and passing the slurry through one or more electromagnetic separation units (EMSU) to remove the iron powder from the slurry, thereby producing an iron-free reactor effluent, and returning the iron powder to the reactor at step (a); and
(d) separating the HCC-240fa from the slurry and returning the remaining contents of the slurry to the reactor at step (a).