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.

Claims

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.sub.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.sub.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.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0123] FIG. 1—Dehydrochlorination step (1,1,1,3-tetrachloropropane conversion to 1,1,3-trichloropropene)

TABLE-US-00001  1 1,1,1,3-tetrachloropropane feed stream  2 ferric chloride feed stream  3 continuously stirred tank reactor  4 reaction residue  5 filter  6 filter cake  7 filtrate  8 distillation column  9 1,1,3-trichloropropene rich stream 10 partial condenser 11 gaseous hydrogen chloride stream 12 1,1,3-trichloropropene rich stream 13 reflux divider 14 reflux stream 15 purified 1,1,3-trichloropropene product stream

[0124] FIG. 2—Aqueous treatment step

TABLE-US-00002 101 aqueous hydrochloric acid feed stream 102 residue feed stream (from the reactor in FIG. 1, stream 4) 103 haloalkane extraction agent feed stream 104 105 washing tank 106 washing tank outlet 107 filter 108 filter cake 109 organic phase stream 110 aqueous phase stream 111 distillation column 112 chlorinated alkanes stream 113 condenser 114 intermediate line 115 reflux liquid-liquid separator 116 aqueous phase (reflux) stream 117 organic phase (1,1,1,3-tetrachloropropane) stream

[0125] FIG. 3—Distillation step

[0126]

TABLE-US-00003 201 organic phase feed stream 202 distillation boiler 203 heavy ends residue stream 204 filter 205 filter cake 206 liquid residue 207 distillation column 208 distillate stream 209 condenser 210 intermediate line 211 reflux divider 212 reflux stream 213.1 1,1,3-trichloropropene fraction 213.2 1,1,1,3-tetrachloropropane fraction

EXAMPLES

Abbreviations Used

[0127] TeCPa=1,1,1,3-tetrachloropropane
TCPe=trichloropropene

Example 1—Production of 1,1,3-Trichloropropene from 1,1,1,3-Tetrachloropropane

[0128] FIG. 1 shows a schematic drawing of a system which can be used to operate processes of the present invention. 1,1,1,3-tetrachloropropane and ferric chloride are added into the continuously stirred tank reactor 3 via lines 1 and 2. The addition of ferric chloride is conducted using a controlled feed. The continuously stirred tank reactor is operated at a temperature of 140° C. to 145° C. and at atmospheric pressure.

[0129] The 1,1,1,3-tetrachloropropane is converted to 1,1,3-trichloropropene in the continuously stirred tank reactor 3, which fulfils the role of the dehydrochlorination zone. The residence time of the reaction mixture in the reactor 3 is limited to prevent the excessive conversion of 1,1,1,3-tetrachloropropane to 1,1,3-trichloropropene and thus, the molar ratio of 1,1,3-trichloropropene:1,1,1,3-tetrachloropropane does not exceed 50:50.

[0130] A proportion of 1,1,3-trichloropropene is extracted from the reaction mixture through the use of distillation column 8. Reaction mixture is fed into the bottom of the distillation column 8 and a 1,1,3-trichloropropene rich stream is withdrawn as overhead vapours via line 9. A partial condenser 10 functions to extract gaseous hydrogen chloride from the 1,1,3-trichloropropene rich stream via line 11. The 1,1,3-trichloropropene rich stream is then fed via line 12 to a reflux divider 13, and a stream of purified 1,1,3-trichloropropene is taken off via line 15. A proportion of the 1,1,3-trichloropropene rich stream is fed back as a reflux to distillation column 8 via line 14.

[0131] A mixture comprising catalyst, unreacted 1,1,1,3-tetrachloropropane and a limited amount of 1,1,3-trichloropropene is extracted via line 4 from the reactor 3 to a filter 5. The obtained filter cake is extracted via line 6 and the filtrate is passed via line 7 for aqueous treatment, as shown in FIG. 2.

[0132] In FIG. 2, the mixture from the reactor in FIG. 1 is fed via line 102 into a washing tank 105 including a stripping boiler. For better liquid phase separation efficiency, 1,1,1,3 tetrachloropropane or another haloalkane extraction agent is fed into the washing tank via line 103. Aqueous hydrochloric acid is fed into the washing tank 105 via line 101.

[0133] A biphasic mixture is formed in the tank 105 and the organic phase is extracted from the tank 105 via line 106, filtered 107 and taken via line 109 for further treatment, as shown in FIG. 3. The remaining aqueous phase is extracted via line 110 for further treatment. The filter cake is extracted (108).

[0134] 1,1,1,3-tetrachloropropane and 1,1,3-trichloropropene dissolved in the aqueous layer present in the washing tank 105 are extracted therefrom by means of a steam distillation column 111. Stripped chlorinated alkanes are passed via line 112 from the distillation column 111 to a condenser 113 and then via line 114 to a reflux liquid-liquid separator 115 where two layers are formed. The stripped 1,1,1,3-tetrachloropropane is then taken off as an organic phase via line 117 and an aqueous phase is refluxed back to the distillation column via line 116.

[0135] Turning to FIG. 3, the organic phase is fed via line 201 into distillation boiler 202. 1,1,1,3-tetrachloropropane and 1,1,3-trichloropropene are extracted from the formed mixture using distillation column 207, condenser 209 and reflux divider 211 to produce fractions of 1,1,3-trichloropropene 213.1 and 1,1,1,3-tetrachloropropane 213.2. The fraction of 1,1,1,3-tetrachloropropane is recycled back to the dehydrochlorination zone while the fraction of 1,1,3-trichloropropene is stored or transported for use in downstream reactions employing that chlorinated alkene as a starting material.

[0136] A heavy ends residue is extracted from boiler 202 via line 203 and filtered 204. The obtained filter cake and liquid residue are extracted via lines 205 and 206 respectively and recycled or treated.

[0137] Using the apparatus and process conditions outlined above, 3563 kg of 1,1,1,3-Tetrachloropropane (1113TeCPa, 99.925% purity) was continuously processed with an average hourly loading 63.1 kg/h to produce 1,1,3-Trichloropropene (113TCPe). Basic parameters of disclosed process carried out according to Example 1 are as following.

TABLE-US-00004 Basic parameters Reactor mean residence time (min) 174 Reactor temperature (° C.) 141 Reactor pressure (kPa) 101 Overall reaction 1113TeCPa conversion (%) 91.7 Overall 113TCpe reaction yield (mol 97.4 TCPe/mol TeCPa converted, in %) Overall 113TCpe yield including the all 96.5 process steps described in Example 1

[0138] The full impurity profile of the purified product of the above-described embodiment is presented in the following table. The figures are given as a weighted average of the profiles for the product obtained in line 15 in FIG. 1 and line 213.1 in FIG. 3.

TABLE-US-00005 Pilot plant Wt % Perchloroethylene 0.011 1,1,3-Trichloropropene 97.093 2,3-dichloropropanoyl chloride 0.028 1,1,3,3-Tetrachloropropene 0.019 1,1,1,3-Tetrachloropropane 2.573 unknown 0.276

[0139] As can be seen, the process of the present invention can be operated to produce highly pure chlorinated alkene material.

Example 2—Production of 1,1,3-Trichloropropane from 1,1,1,3-Tetrachloropropane

[0140] This example was conducted using the apparatus and techniques employed in Example 1 above, except where otherwise stated. The continuously stirred tank reactor was operated at a temperature of about 149° C. and at atmospheric pressure. The molar ratio of 1,1,3-trichloropropene:1,1,1,3-tetrachloropropane in the reactor was controlled such that it did not exceed 30:70. Using the apparatus and process conditions outlined above, 1543.8 kg of 1,1,1,3-Tetrachloropropane (1113TeCPa, 99.901% purity) was continuously processed with an average hourly loading 47.5 kg/h to produce 1,1,3-Trichloropropene (113TCPe). Catalyst was added in the form of FeCl.sub.3 aqueous solution to provide a catalyst content of 66 ppm, based on feedstock 1113TeCPa. Basic parameters of disclosed process carried out according to Example 1 are as following.

TABLE-US-00006 Basic parameters Reactor mean residence time (min) 287 Reactor temperature (° C.) 149 Reactor pressure (kPa) 101 Overall reaction 1113TeCPa conversion (%) 91.4 Overall 113TCPe reaction yield 98.7 (mol TCPe/mol TeCPa converted, in %) Overall 113TCPe yield in % including 97.8 the all process steps described in Example

[0141] The full impurity profile of the product of the above-described embodiment is presented in the following table. The figures are given as a weighted average of the profiles for the product obtained in line 15 in FIG. 1 and line 213.1 in FIG. 3.

TABLE-US-00007 Compound Wt % Perchloropethylene 0.006 3,3,3-Tetrachlororpropene 0.038 1,1,3-Tetrachloropropene 99.347 2,3-dichloropropanoyl chloride 0.045 1,1,3,3-Tetrachloropropene 0.004 1,1,1,3-Tetrachloropropane 0.322 unknown 0.238

[0142] As can be seen, when the dehydrochlorination reaction is controlled such that the molar ratio of 1,1,3-trichloropropene:1,1,1,3-tetrachloropropane does not exceed 30:70, the process of the present invention can be operated to produce highly pure chlorinated alkene material with the very high selectivity and in high yield. Of note is that 3,3,3-Tetrachlororpropene is only formed in trace amounts. This is particularly advantageous as 3,3,3-Tetrachloropropene is a very reactive olefin contaminant with a free induced (activated) double bond and can be a precursor of highly problematic oxygenated impurities.

Example 3—Alkene:Alkane Ratio in Reaction Mixture

[0143] These examples were conducted using the apparatus and techniques employed in Example 1 above, except where otherwise stated. In each of these trials, the reaction progress was controlled such that there was a different ratio between 1,1,3-Trichloropropene:1,1,1,3-Tetrachloropropane in the reaction mixture present in the reactor (equip. 3) reaction mixture (stream 7) in each trial. The amount of dosed catalyst FeCl.sub.3 was controlled to maintain the reaction conversion rate at about 90%. The influence of different levels of 113TCPe in reaction mixture on the heavy oligomers formation and catalyst deactivation is shown in the following tables:

TABLE-US-00008 Heavy Oligomer Formation 3-1 3-2 3-3 3-4 3-5 3-6 Calculated 23:77 22:78 34:66 43:57 46:54 43:57 TCPe:TeCPa molar ratio in reac. mix TCPe (%) in 18.95 18.25 27.6 34.54 32.01 34.31 reaction mixture Heavy 0.36% 0.40% 1.05% 1.57% 2.87% 2.54% oligomers/ TCPe 3-7 3-8 3-9 3-10 3-11 3-12 Calculated 39:61 37:63 40:60 39:61 38:62 39:31 TCPe:TeCPa molar ratio in reac. mix TCPe (%) in 32.1 29.94 32.84 31.46 30.56 31.83 reaction mixture Heavy 1.56% 1.79% 1.65% 1.01% 1.47% 1.55% oligomers/ TCPe

TABLE-US-00009 Catalyst Deactivation 3-1 3-2 3-3 3-4 3-5 3-6 TCPe (%) in 18.95 22.36 27.6 34.54 32.01 34.313 reaction mixture −1 Calculated 23:77 22:78 34:66 43:57 46:54 43:57 TCPe:TeCPa molar ratio in reac. mix Required 26.5 26.5 66 101 116 78 conc.of FeCl3 in feedstock 3-7 3-8 3-9 3-10 3-11 3-12 TCPe (%) in 32.1 29.94 32.84 31.46 30.56 31.83 reaction mixture Calculated 39:61 37:63 40:60 39:61 38:62 39:61 TCPe:TeCPa molar ratio in reac. mix Required 132 132 105 177 106 74 conc. of FeCl3 in feedstock

[0144] As can be seen from this example, when the specific apparatus and techniques employed, an increase in the molar ratio of the product to the starting material (increased amount of the product in the reaction mixture) corresponds to an increase in the formation of heavy oligomers. Further, if the 1,1,3-Trichloropropene concentration is high, catalyst deactivation was also observed.

Example 4—Compatibility of the Product Fluid with Various Materials

[0145] An Erlenmeyer glass flask was filled with pure distilled 1,1,3-Trichloropropene with purity of >99%. The test construction material sample was immersed in the liquid and the system was closed with a plastic plug.

[0146] Samples of the Trichloropropene were regularly taken from the flask. The construction material samples were weighed before and after trail. The temperature of the liquid was ambient laboratory conditions, around 25° C.

[0147] The major changes in the quality of the Trichloropropene are shown in the following table, as a % change in purity:

TABLE-US-00010 Feedstock 4-1 4-2 4-3 4-4 Trial duration 0 day 29 days 29 days 30 30 Construction CS SS days days Material 1.4541 Ti C-276 1,1,3- 0 −53.75 −3.70 −3.27 −0.67 Trichloropropene- relative change (%) Sum of 0 42.68 0.20 0.32 0.01 oligomers (%)

[0148] CS=carbon steel, SS=stainless steel, Ti=Titanium, C-276=Hastelloy C-276

[0149] In a second set of trials, an Erlenmeyer glass flask equipped with a back cooler and oil heating bath with controlled temperature was filled with pure distilled 1,1,3-Trichlorpropene with a purity of >99%. The test material sample was immersed in the liquid and the system was partially closed using a plastic plug. Samples of Trichloropropene were regularly taken from the flask. The material samples were weighed before and after trail. The temperature of the liquid was controlled at 100° C. The major changes in the liquid Trichloropropene are shown in the following table:

TABLE-US-00011 feedstock 4-5 4-6 4-7 4-8 Trial duration 0 day 5 hours 48 hours 5 hours 48 hours Construction Material Glass as material Impregnated of flask graphite 1,1,3- 0 −0.32 −2.31 −0.30 −2.00 Trichloropropene- relative change (%) Sum of oligomers (%) 0 0.05 0.28 0.05 0.34 feedstock 4-9 h 4-10 4-11 4-12 Trial duration 0 hours 5 hours 48 hours 5 hours 48 hours Construction Material SS 1.4341 SS 1.4541 1,1,3- 0 −0.54 −3.08 −0.51 −2.80 Trichloropropene- relative change (%) Sum of oligomers (%) 0 0.27 1.01 0.29 1.29

[0150] As can be seen from this example, the use of carbon steel appeared to be challenging as it is not compatible with the process fluid consisting of 1,1,3-Trichlorpropene. Stainless steel and titanium have also poor performance, resulting in the formation of significant amounts of oligomers are formed. From the tested metal materials, the Ni-alloy Hastelloy C-276 has excellent results. It can be seen also that glass (or enamel) and other non-metallic material, such as phenolic resin impregnated graphite, are also more suitable.

Example 5—Problematic Chlorinated Alkene Impurities

[0151] In many downstream reactions in which chlorinated alkenes are used as starting materials, the presence of oxygenated organic impurities is problematic. This example demonstrates that certain impurities have a surprising propensity to form such compounds.

[0152] A four neck glass flask equipped with a stirrer, thermometer, back cooler, feed and discharge neck and cooling bath was filled with water and chlorine gas was bubbled into the water to produce a weak solution of hypochlorous acid. When an appropriate amount of chlorine had been introduced into the water, a feedstock consisting obtained from the process of Example 1 comprising 1,1,3-Trichloropropene with a purity of 98.9% was slowly dropped into the prepared solution of hypochlorous acid for a period of 90 min and cooled. The pressure was atmospheric and temperature close to 20° C. The same procedure was repeated with 3,3,3-Trichlorpropene having a purity of 68.1%. After reaction completion the systems formed bi-phasic mixtures. The organic phase (product) was extracted and then analyzed by GC. The results are shown in the following table:

TABLE-US-00012 5-1 5-2 Hypochlorination of Feedstock Product Feedstock Product Trichloropropenes (%) (%) (%) (%) 3,3,3-Trichloropropene 68.063 33.544 0.024  0.023 1,1,3-Trichloropropene 21.772 16.651 98.922 91.374 1,1,1,2,3-Pentachloropropane 20.942  6.800 1,1,1,3-Tetrachloropropan-2-ol 12.792  0.018

[0153] As can be seen from this example, 1,1,3-Trichlorpropene reacts with chlorine in water to produce 1,1,1,2,3-Pentachloropropane, while 3,3,3-Trichloropropene reacts significantly to produce corresponding tetrachlorohydrines, especially 1,1,1,3-Tetrachloropropan-2-ol.

[0154] In other words, 1,1,3-Trichlorpropene reacts to produce a product of commercial interest, while 3,3,3-Trichloropropene reacts to the produce an oxygenated impurity which cannot be easily removed from the 1,1,1,2,3-Pentachloropropane. As is apparent from Examples 1 and 2 above, the processes of the present invention can be advantageously employed to produce 1,1,3-trichloropropene resulting in the formation of only trace amounts of 3,3,3-trichloropropene.