Process for producing a chlorinated C.SUB.3-6 .alkane

Abstract

Disclosed is a process for producing a chlorinated C3-6 alkane comprising providing a reaction mixture comprising an alkene and carbon tetrachloride in a principal alkylation zone to produce chlorinated C3-6 alkane in the reaction mixture, and extracting a portion of the reaction mixture from the principal alkylation zone, wherein: a) the concentration of the chlorinated C3-6 alkane in the reaction mixture in the principal alkylation zone is maintained at a level such that the molar ratio of chlorinated C3-6 alkane:carbon tetrachloride in the reaction mixture extracted from the alkylation zone does not exceed 95:5 when the principal alkylation zone is in continuous operation; and/or b) the reaction mixture extracted from the principal alkylation zone additionally comprises alkene and the reaction mixture is subjected to a dealkenation step in which at least about 50% or more by weight of the alkene present in the reaction mixture is extracted therefrom and at least about 50% of the extracted alkene is fed back into the reaction mixture provided in the principal alkylation zone; and/or c) the reaction mixture present in the principal alkylation zone and extracted from the principal alkylation zone additionally comprises a catalyst, and the reaction mixture extracted from the principal alkylation zone is subjected to an aqueous treatment step in which the reaction mixture is contacted with an aqueous medium in an aqueous treatment zone, a biphasic mixture is formed and an organic phase comprising catalyst is extracted from the biphasic mixture.

Claims

1. A process for producing a chlorinated C.sub.3-6 alkane comprising providing a reaction mixture comprising an alkene, carbon tetrachloride and a catalyst in an alkylation zone to produce chlorinated C.sub.3-6 alkane in the reaction mixture, and extracting a portion of the reaction mixture from the alkylation zone, wherein: the concentration of the chlorinated C.sub.3-6 alkane in the reaction mixture in the alkylation zone is maintained at a level such that the molar ratio of chlorinated C.sub.3-6 alkane:carbon tetrachloride in the reaction mixture extracted from the alkylation zone does not exceed 95:5 when the alkylation zone is in continuous operation; wherein the reaction mixture extracted from the alkylation zone is subjected to an aqueous treatment step with diluted hydrochloric acid in which a biphasic mixture is formed and an organic phase comprising the catalyst is extracted from the biphasic mixture.

2. The process of claim 1, wherein the alkene is ethene, propene and/or chlorinated propene.

3. The process of claim 1, wherein the chlorinated C.sub.3-6 alkane is 1,1,1,3-tetrachloropropane.

4. The process of claim 1, wherein the catalyst is a metallic catalyst, further comprising an organic ligand.

5. The process of claim 4, wherein the organic ligand is tributylphosphate.

6. The process of claim 1, wherein the organic phase extracted from the biphasic mixture is fed back to the alkylation zone.

7. A process for producing 1,1,1,3-tetrachloropropane, comprising providing a reaction mixture comprising ethene, carbon tetrachloride, a metallic catalyst and an organic ligand in an alkylation zone to produce 1,1,1,3-tetrachloropropane in the reaction mixture, and extracting a portion of the reaction mixture from the alkylation zone, wherein the reaction mixture extracted from the alkylation zone is subjected to an aqueous treatment step with diluted hydrochloric acid, in which a biphasic mixture is formed and an organic phase is extracted from the biphasic mixture; and the organic phase extracted from the biphasic mixture comprises carbon tetrachloride, 1,1,1,3-tetrachloropropane, tetrachloropentane and the organic ligand.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1—Alkylation step

(2) TABLE-US-00001 1 ethene feed stream 2 particulate iron feed stream 3 continuously stirred tank reactor 4 plug/flow reactor 5 reaction mixture stream 6 flash evaporation vessel 7 1,1,1,3-tetrachloropropane-rich mixture stream 8 evaporated ethene stream 9 condenser 10 ethene stream 11 absorption column 12 carbon tetrachloride and tributyl phosphate/ferric chloride catalyst feed stream 13 stream of recovered catalyst (tributyl phosphate/ferric chloride), fresh catalyst and carbon tetrachloride 14 cooler 15 cooled stream of recovered catalyst (tributyl phosphate/ ferric chloride), fresh catalyst and carbon tetrachloride 16 off-gas

(3) FIG. 2—First distillation step

(4) TABLE-US-00002 101 1,1,1,3-tetrachloropropane-rich mixture stream extracted from the flash evaporation vessel (6), FIG. 1 102 batch distillation boiler 103 stream of 1,1,1,3-tetrachloropropane-rich mixture comprising catalyst 104 vacuum distillation column 105 distillate stream 106 condenser 107 intermediate line 108 reflux divider 109 reflux stream 110.1 light ends stream 110.2 carbon tetrachloride stream 110.3 tetrachloroethene stream 110.4 purified 1,1,1,3-tetrachloropropane product stream

(5) FIG. 3—Aqueous catalyst recovery step

(6) TABLE-US-00003 201 weak hydrochloric acid solution stream 202 1,1,1,3-tetrachloropropane-rich mixture feed stream comprising catalyst 203 haloalkane extraction agent feed stream (1,1,1,3- tetrachloropropane) 204 batch distillation boiler 205 batch distillation boiler outlet 206 filtration 207 filter cake removal 208 organic phase extraction (part of the feed stream 13 in FIG. 1) 209 aqueous phase disposal 210 column for steam distillation of crude 1,1,1,3- tetrachloropropane 211 crude 1,1,1,3-tetrachloropropane stream 212 condenser 213 condensed crude 1,1,1,3-tetrachloropropane stream 214 reflux liquid-liquid separator 215 reflux stream 216 crude 1,1,1,3-tetrachloropropane stream for further distillation

(7) FIG. 4—Second distillation step

(8) TABLE-US-00004 301 crude 1,1,1,3-tetrachloropropane product feed stream 302 distillation boiler 303 heavy ends residue 304 distillation column 306 condenser 308 reflux divider 310.1 purified 1,1,1,3-tetrachloropropane product stream 310.2 chlorinated pentane/pentene stream

EXAMPLES

(9) The present invention is now further illustrated in the following examples.

Example 1—Demonstration of Catalytic Ability of Recovered Catalyst Using an Aqueous Treatment

(10) Ethene and carbon tetrachloride were reacted to produce 1,1,1,3-Tetrachloropropane in the presence of catalyst which was either i) recovered from a reaction mixture using conventional distillation techniques, or ii) recovered from a reaction mixture using the inventive aqueous treatment step for catalyst described herein. The reaction mixture additionally comprised 1,1,1,3-Tetrachloropropane (present in the recycle stream) and tetrachloropentane (a chlorinated alkane impurity commonly formed as a byproduct in the presence of telomerisation reactions between carbon tetrachloride and ethene).

(11) These test examples show that using the aqueous treatment step to recover catalyst, the performance of the catalyst is significantly higher as compared to catalyst recovered using conventional distillation techniques.

(12) For brevity, the following terms are used in the examples set out below:

(13) TeCM: tetrachloromethane.

(14) TeCPa: 1,1,1,3-Tetrachloropropane

(15) TeCPna: tetrachloropentane,

(16) Bu.sub.3PO.sub.4: Tributylphosphate

(17) Gas chromatography was used to monitor the progress of the reaction.

(18) Batchwise Arrangement

(19) A stainless steel autoclave with a volume of 405 ml, equipped with a stirrer, a thermowell for temperature measurement and a sampling tube (with valve) was filled with the reaction mixture described below and closed. Heating was provided by means of an oil bath placed on a magnetic (heating) stirrer. Ethene was fed by a copper capillary tube from 10 l cylinder placed on weighing scale. The gaseous atmosphere in the autoclave was replaced by ethene flushing. After pressurizing with ethene to 5 bar, the autoclave was heated up to 105° C., then the ethene supply to the autoclave was opened. Ethene supply was controlled manually for a first ten minutes (to maintain the reaction temperature to 112° C.), and later was maintained at a constant pressure of 9 bar. The reaction was allowed to react defined time period. Than the reactor was cooled and reaction mixture was withdrawn after opening of depressurised reactor.

Comparative Examples 1-1 and 1-3 and Examples 1-2, 1-4 and 1-5

(20) In the first example, the distillation residue was directly used as a recycled catalyst (Comparative Example 1-1). In the second example, the distillation residue was extracted with 5% hydrochloric acid and a filtered organic fraction was used as a catalyst (Example 1-2).

Comparative Example 1-1

(21) 90.1 g of a distillation residue comprising 63.7% TeCPa, 22.8% TeCPna and 7.49% Bu.sub.3PO.sub.4 was mixed with 400 g of TeCM. The mixture was then introduced into the autoclave where 5.0 g of iron was added. After flushing with ethene, the mixture was heated in the autoclave up to 110° C. At this temperature and at a pressure of 9 bar of ethene, the reaction mixture was allowed to react for 4.5 hours. The first sample was taken after 3 hours. The concentration of residual TeCM at the end of the experiment was 19.7% (33.0% after 3 hours).

Example 1-2

(22) 90.1 g of a distillation residue comprising 63.7% TeCPa, 22.8% TeCPna and 7.49% Bu.sub.3PO.sub.4 was extracted with 370 g of 5% HCl. A bottom organic layer was filtered and mixed with 400 g TeCM. The mixture was then introduced into the autoclave where 5.0 g of iron was added. After flushing with ethene, the mixture was heated in the autoclave up to 110° C. At this temperature and at a pressure of 9 bar of ethene, the reaction mixture was allowed to react for 4.5 hours. The first sample was taken after 3 hours. The concentration of residual TeCM at the end of the experiment was 5.5% (24.6% after 3 hours).

Comparative Example 1-3

(23) Comparative Example 1-3 was carried out using identical conditions as those employed in Comparative Example 1-1, except that differing concentrations of tetrachloromethane and tributylphosphate were used.

Example 1-4 and 1-5

(24) Examples 1-4 and 1-5 were carried out using identical conditions as those employed in Example 1-2, except that differing concentrations of tetrachloromethane and tributylphosphate were used.

(25) The results of Comparative Example 1-1 and Example 1-2, and Comparative Example 1-3 and Examples 1-4 and 1-5 are shown in the following table. As can be seen, the percentage of tetrachloromethane which was converted to 1,1,1,3-Tetrachloropropane is significantly higher in Examples 1-2, 1-4 and 1-5 than in Comparative Examples 1-1 and 1-3 demonstrating that the performance of an aqueous treatment step when recovering the catalyst has a profound positive effect on the system. This is due to the high viability of the catalyst recovered from the distillate residue and also potentially due to the removal of impurities (e.g. oxygenated impurities) from the reaction mixture which otherwise may retard the reaction.

(26) TABLE-US-00005 % TeCM in the % of reacted TeCM Example Bu.sub.3PO.sub.4 feedstock 3 hrs. 4.5 hrs. Comparative 1.37% 84.7% 57.4% 73.8% Example 1-1 Example 1-2 1.35% 83.7% 67.3% 92.4% Comparative 1.77% 78.7% 60.0% 78.1% Example 1-3 Example 1-4 1.64% 81.2% 87.7% 99.4% Example 1-5 1.64% 70.6% 78.7% 99.4%

(27) Continuous Arrangement:

(28) The same stainless steel autoclave as described above for the batch experiments was used as a stirred flow continuous reactor. The reactor was initially filled with approximately 455 g of reaction mixture. After pressurizing with ethene to 5 bar, the autoclave was heated up to 105° C., then the ethene supply to the autoclave was opened, with continuous feed of the raw material and continuous withdrawal of the reaction mixture started.

(29) Feedstock solution with dissolved catalyst was fed into the autoclave from a stainless steel tank. The tank was placed above the reactor, and thus, a pump was not used for feeding the reactor. Reactor and tank were under an atmosphere of ethene distributed by copper capillaries from the cylinder, with conditions in the cylinder selected to prevent commencement of the reaction. Sampling of the reaction mixture was carried out by sampling tube every five minutes. To monitor the course of the reaction, the container with the feedstock and dissolved catalyst, cylinder of ethene and the withdrawn reaction mixture were weighed. The reaction mixture was always collected for an hour and after that, the collecting vessel is replaced.

Comparative Example 1-6 and 1-8 and Examples 1-7 and 1-9

(30) Continuous experiments comparing the activity of recycled catalyst (i.e. a distillation residue were conducted with and without performance of an aqueous treatment step. In the first case, the distillation residue was directly used as a recycled catalyst (Comparative Example 1-6). In the latter cases, the reaction mixture, after aqueous treatment of the distillation residue with 5% HCl, was used as a raw material containing recycled catalyst (Examples 1-4 and 1-5).

Comparative Example 1-6

(31) 587.5 g of the distillation residue comprising 63.7% TeCPa, 22.8% TeCPna and 7.49% Bu3PO4 was mixed with 2200 g of TeCM. This mixture comprised 78.7% TeCM, 11.8% TeCPa, 5.8% TeCPna and was used as a feed stream for the continuous arrangement. The reaction vessel constituted an autoclave was filled with reaction mixture and 8 g of fresh iron. The reaction was carried out at 110° C. with a pressure of ethene of 9 bar. The residence time was 2.7 hours. During the reaction, the amount of reacted TeCM ranged between 75-76%.

Example 1-7

(32) 587.5 g of the distillation residue comprising 63.7% TeCPa, 22.8% TeCPna 7.49% Bu.sub.3PO.sub.4 was added dropwise over 1.5 hour into 1001.5 g of boiling 5% HCl. This mixture was then stripped. From the overhead product, an organic phase was collected and an aqueous phase was returned as a reflux. Distillation was terminated after an hour when all of the distillation residue was added. The residue, after stripping, was diluted with 200 g of TeCM and then separated in a separatory funnel. A bottom organic phase was filtered and together with distilled residue was mixed with 2000 g of TeCM. This mixture comprised 81.2% TeCM, 10.8% TeCPa and 5.3% TeCPna. It was used as a feed stream for the continuous arrangement of the experiment. The reaction vessel (autoclave) was filled with the older reaction mixture and 8 g of fresh iron. The reaction was carried out at 110° C. and a pressure of ethene of 9 bar. Residence time was 2.7 hours/flow rate. During the time of the reaction the amount of reacted TeCM ranged between 83-85%.

Comparative Example 1-8

(33) Comparative Example 1-8 was carried out using identical conditions as those employed in Comparative Example 1-6, except that differing concentrations of tetrachloromethane and tributylphosphate were used.

Example 1-9

(34) Example 1-9 was carried out using identical conditions as those employed in Example 1-7, except that differing concentrations of tetrachloromethane and tributylphosphate were used.

(35) TABLE-US-00006 % TeCM Example (recycled in the % reacted catalyst) Bu.sub.3PO.sub.4 feedstock TeCM Comparative 1.67% 78.7% 75.0%.sup.  Example 1-6 Example 1-7 1.64% 81.2% 84% Comparative 1.83% 76.8% 60% Example 1-8 Example 1-9 1.89% 78.0% 89%

Example 2—Preparation of High Purity 1,1,1,3-Tetrachloropropane

(36) High purity 1,1,1,3-Tetrachloropropane may be obtained according to a process of the present invention involving an alkylation step (FIG. 1), a first distillation step (FIG. 2), an aqueous catalyst recovery step (FIG. 3) and a second distillation step (FIG. 4). However, it will be appreciated that not all of these steps are necessary to obtain high purity C.sub.3-6 alkane according to the processes of the present invention.

(37) In the alkylation step shown in FIG. 1, ethene and particulate iron are fed via lines 1 and 2 into a continuously stirred tank reactor 3. The ethene is introduced into the continuously stirred tank reactor 3 in gaseous form via a dip tube provided with a nozzle. A controlled feed of particulate iron is fed into the continuously stirred tank reactor 3.

(38) Particulate iron is intermittently fed into the continuously stirred tank reactor 3 using a controlled feed. The ongoing addition of particulate iron is employed because, as the alkylation reaction proceeds, particulate iron dissolves into the reaction mixture. It has been found that optimal results are obtained by maintaining the presence of particulate iron in the reaction mixture, in this example with the addition of 1 to 2% by weight of the reaction mixture in the primary alkylation zone. This results in the reaction mixture extracted from the primary alkylation zone having a dissolved iron content of 0.2 to 0.3% by weight of the reaction mixture.

(39) Carbon tetrachloride is fed into the continuously stirred tank reactor 3 via line 12 in liquid form. In the illustrated embodiment, the carbon tetrachloride stream is used to trap gaseous ethene extracted from the reaction mixture. However, the use of carbon tetrachloride in this way is not essential to the present invention; a feed of fresh carbon tetrachloride as the sole or main source of carbon tetrachloride could be fed into the reactor 3.

(40) Tributyl phosphate/ferric chloride catalyst is also fed into the continuously stirred tank reactor 3 via line 12. The tributyl phosphate present in that stream is partly obtained from the aqueous treatment process illustrated in FIG. 3 (and discussed below in more detail), with the balance being provided as fresh tributyl phosphate added into the system. The stream in line 12 additionally comprises a haloalkane extraction agent.

(41) In the illustrated embodiment, a single primary alkylation zone is employed, located in the continuously stirred tank reactor 3. Of course, if required, a plurality of primary alkylation zones could be employed, for example in one or more continuously stirred tank reactors, that could be operated in parallel and/or in series.

(42) The primary alkylation zone is operated under superatmospheric pressure (5 to 8 bar gauge) and elevated temperature (105° C. to 110° C.) and for a residence time of 100-120 minutes. These conditions are selected to cause the carbon tetrachloride and ethene to form 1,1,1,3-Tetrachloropropane in an alkylation reaction. However, it has been found that the total conversion of carbon tetrachloride to 1,1,1,3-Tetrachloropropane is undesirable as this also results in the formation of unwanted impurities. Thus the level of conversion of the carbon tetrachloride to the chlorinated C.sub.3-6 alkane of interest is controlled and, in this embodiment of the invention, is not permitted to proceed beyond 95% Control of the progress of the alkylation reaction is achieved partly through use of reaction conditions which do not favour the total conversion of carbon tetrachloride to 1,1,1,3-Tetrachloropropane, through control of the residence time of the reaction mixture in the continuously stirred tank reactor.

(43) Reaction mixture comprising i) unreacted carbon tetrachloride and ethene, ii) 1,1,1,3-Tetrachloropropane (the chlorinated C.sub.3-6 alkane of interest in this embodiment) and iii) tributyl phosphate/iron chloride catalyst is extracted from the primary alkylation zone (the continuously stirred tank reactor 3) and fed into a plug/flow reactor 4 (in which the principal alkylation zone is located).

(44) The reaction mixture is extracted such that particulate iron catalyst present in the primary alkylation zone 3 is not extracted and thus the reaction mixture is substantially free of particulate material. Further, in the illustrated embodiment, no additional catalyst is added into the plug/flow reactor 4, although the plug/flow reactor 4 may provided with a catalyst bed. Additionally, no further ethene is added into the plug/flow reactor 4.

(45) In the illustrated embodiment, the operating pressure in the principal alkylation zone 4 is the same as that in the primary alkylation zone 3. The residence time of the reaction mixture is about 30 minutes, which in the illustrated embodiment was sufficient to result in substantially all of the ethene present being used up in the reaction. Of course, it will be understood that for different reactor types and operating conditions, different resident times may be optimal.

(46) When the determined optimal residence time of the reaction mixture in the principal alkylation zone has been reached, reaction mixture is extracted therefrom via line 5, while being maintained at elevated pressure and temperature, and fed into flash evaporation vessel 6. In this vessel, the extracted reaction mixture is subjected to depressurisation, to atmospheric pressure. This pressure drop causes evaporation of the ethene present in the reaction mixture. The 1,1,1,3-Tetrachloropropane-rich mixture, now with substantially no ethene present, is extracted from the flash vessel via line 7 and subjected to the distillation step shown in FIG. 2, and discussed below in more detail.

(47) The evaporated ethene is extracted from the flash vessel 6 via line 8 and fed through a condenser 9. The ethene is then fed via line 10 into absorption column 11 where it is contacted with a stream of carbon tetrachloride and tributyl phosphate/iron chloride catalyst, recovered from the reaction mixture in the aqueous treatment step shown in FIG. 3, and discussed below in more detail. The stream of recovered catalyst/carbon tetrachloride 13 is passed through a cooler 14 and then fed via line 15 into the absorption column 11.

(48) The flow of cooled carbon tetrachloride/catalyst through the absorption column 11 has the effect of trapping the ethene therein. The obtained liquid flow of carbon tetrachloride/catalyst/ethene is then fed back into the continuously stirred tank reactor 3.

(49) As is apparent from FIG. 1, the illustrated embodiment includes an ethene recycling loop which is advantageous for several reasons. First, almost total utilisation of the ethene is achieved and thus the amount of ethene lost from the system is very low. Additionally, the energy requirements of the components of the ethene recycling system are also low. Further, the amount of ethene lost from the system is also very low, meaning that the environmental burden is reduced.

(50) Turning now to FIG. 2, the 1,1,1,3-Tetrachloropropane-rich mixture extracted from the flash vessel shown with reference numeral 6 in FIG. 1, is fed via line 101 into a batch distillation boiler 102 which is operated in communication with a vacuum distillation column 104. The distillation boiler is operated at a temperature of 90° C. to 95° C. Chloroalkanes present in the mixture fed into the boiler 102 are evaporated and separated using distillation column 104 (and the downstream condenser 106 and reflux divider 108) into light ends stream 110.1, carbon tetrachloride stream 110.2, tetrachloroethene stream 110.3 and purified 1,1,1,3-Tetrachloropropane product stream 110.4.

(51) The light ends and tetrachloroethene streams 110.1, 110.3 may be used in the production of carbon tetrachloride, advantageously minimising the production of waste products. This can be achieved through use of a high temperature chlorinolysis process.

(52) The carbon tetrachloride stream 110.2 is recycled back into the continuously stirred tank reactor 103. The purified 1,1,1,3-Tetrachloropropane product stream 110.4 is extracted from the system and may be stored for shipment or employed in downstream processes requiring pure 1,1,1,3-Tetrachloropropane as a starting material.

(53) A 1,1,1,3-Tetrachloropropane-rich mixture which also comprises catalyst is extracted as a residue from boiler 102 via line 103 and is subjected to the catalyst recovery step shown in FIG. 3.

(54) In that step, the 1,1,1,3-Tetrachloropropane-rich mixture is fed into a batch distillation boiler 204 via line 202, along with a weak (1-5%) hydrochloric acid solution via line 201.

(55) Advantageously, the water present in the acid solution deactivates the catalyst system and protects it from thermal damage. This enables the catalyst system, to be recovered from the 1,1,1,3-Tetrachloropropane-rich mixture, and it can be easily reactivated, post-recovery, and reused in the alkylation process without any significant loss in catalytic activity.

(56) The batch distillation boiler is operated at a temperature of about 100° C., to create a gaseous mixture comprising 1,1,1,3-Tetrachloropropane and water vapour.

(57) The gaseous mixture produced in the boiler 204, is then subjected to steam distillation (or steam stripping) of crude 1,1,1,3-Tetrachloropropane in column 210, which is coupled to the boiler 204. The crude 1,1,1,3-Tetrachloropropane is extracted from the distillation column 210 via line 211, condensed with a condenser 212, fed via line 213 to a reflux liquid-liquid separator 214. Water from the gaseous mixture is fed back to the distillation column 210 via line 215, and a portion is taken off via line 216 for a further distillation step, shown in more detail in FIG. 4 and discussed below in more detail.

(58) The operating temperature of the boiler 204 is then reduced to stop steam stripping, resulting in the condensation of the water vapour present therein. This results in the formation of a biphasic mixture containing an aqueous phase and an organic phase containing the catalyst system, which has not be subjected to steam stripping. To facilitate extraction of the organic phase, a haloalkane extraction agent (in this case, 1,1,1,3-Tetrachloropropane) is added to the boiler 204 via line 203 to increase the volume of that phase.

(59) Extraction of the organic phase from the biphasic mixture is achieved by the sequential extraction of the phases from the boiler 204 via line 205. The organic phase is extracted from the boiler 204 via line 205 and is filtered 206. A filter cake is removed from the filter 206 via line 207. The organic phase is extracted via line 208 and, in this embodiment, fed back to the primary alkylation zone, as shown in FIG. 1, specifically via line 13 in FIG. 1. The aqueous phase is extracted via line 5, filtered 6 and disposed of via line 209.

(60) The stripped crude 1,1,1,3-Tetrachloropropane product is subjected to a further distillation step shown in FIG. 4. In that step, the crude product is fed into a distillation boiler 302 via line 301. The boiler 302 is in communication with distillation column 304. Evaporated chlorinated organic compounds present in the crude 1,1,1,3-Tetrachloropropane are separated in the distillation column 304 (and related downstream apparatus, condenser 306 and reflux divider 308) into a purified 1,1,1,3-Tetrachloropropane product stream 310.1 and chlorinated pentane/pentene stream 310.2.

(61) The chlorinated pentane/pentene stream 310.2 may be used in the production of carbon tetrachloride, advantageously minimising the production of waste products. This can be achieved through use of a high temperature chlorinolysis process.

(62) The purified 1,1,1,3-Tetrachloropropane product stream 310.1 is extracted from the system and may be combined with the major product stream (identified with reference numeral 110.4 in FIG. 2. The product may be stored for shipment or employed in downstream processes requiring pure 1,1,1,3-Tetrachloropropane as a starting material.

(63) The heavy ends residue extracted from the boiler 302 via line 303 is either disposed of or further processed.

(64) Using the apparatus and process conditions outlined above, 2635 kg of carbon tetrachloride (CTC, 99.97% purity) was continuously processed with an average hourly loading 78.2 kg/h to produce 1,1,1,3-Tetrachlorpropene (1113TeCPa). Basic parameters of disclosed process carried out according to Example 2 are as following.

(65) TABLE-US-00007 Basic parameters First reactor mean residence time (min) 118 First reactor temperature range (° C.) 100-110 First reactor pressure (kPa) 800 Second reactor mean residence time (min) 25 Second reactor temperature range (° C.) 100-110 Second reactor pressure (kPa) 800 Overall reaction CTC conversion (%) 91.0 Overall 1113TeCpa reaction yield (mol TeCPa/mol CTC 95.5 converted, in %) Overall 1113TeCpa yield including the all process steps 94.0 described in Example 2

(66) The full impurity profile of the purified product of the above-described embodiment is presented in the following table. Please note that the figures are given as a weighted average of the profiles for the product obtained in line 110.4 in FIG. 2 and line 310.1 in FIG. 4.

(67) TABLE-US-00008 Compound (% wt) Trichloromethane 0 1,2-Dichloroethane 0 1-chlorobutane 0.023 Tetrachloromethane 0.008 1,1,1-Trichloropropane 0.001 Tetrachloroethene 0.006 1,1,3-Trichlroroprop-1-ene 0.014 1,1,1,3-Tetrachloropropane 99.925 1,1,1,3,3-Pentachloropropane 0.004 hexachloroethane 0.012 1,1,1,2,3-Pentachloropropane 0.005 1,1,1,5-Tetrachloropentane 0 1,3,3,5-Tetrachloropentane 0 Tributylphosphate 0 Unknown 0.007

Example 3: Effect on Selectivity of Molar Ratio of Starting Material:Product in Reaction Mixture

(68) These examples were carried out using the equipment and techniques outlined above in the ‘Continuous Arrangement’ in Example 1, except where otherwise stated. The molar ratio of the chlorinated C.sub.3-6 alkane product (in this case, 1,1,1,3-Tetrachloropropane):carbon tetrachloride in the reaction mixture was controlled to differing levels, principally by the residence time of reaction mixture in the alkylation zone. Temperature was maintained at 110° C. and pressure was maintained at 9 Bar. The selectivities towards product of interest are reported in the following table:

(69) TABLE-US-00009 Selectivity of mol. ratio Tetrachloromethane Trial No. 1113TeCPa:Tetrachloromethane towards 1113TeCPa 3-1 79.0:21.0 96.6 3-2 84.4:15.6 95.2 3-3 89.8:10.2 95.5 3-4 93.9:6.1  94.1 3-5 98.0:2.0  90.3

(70) As can be seen from this example, when the molar ratio of product:starting material exceeds 95:5 when the process is operated on a continuous basis, there is a notable reduction in selectivity towards the product of interest.

Example 4: Effect on Selectivity of Molar Ratio of Starting Material:Product in Reaction Mixture

(71) These examples were carried out using the equipment and techniques as illustrated in FIG. 1, with reference to the accompanying text in Example 2 above, except where otherwise stated. The molar ratio of the chlorinated C.sub.3-6 alkane product (in this case, 1,1,1,3-Tetrachloropropane):carbon tetrachloride in the reaction mixture was controlled to differing levels, principally by control of the feed rate of the ethylene starting material. Temperature was constantly 110° C. The selectivities towards the product of interest are reported in the following table:

(72) TABLE-US-00010 Selectivity of mol. ratio Tetrachloromethane Trial No. 1113TeCPa:Tetrachloromethane towards 1113TeCPa 4-1 91.5:8.5 95.6 4-2 95.3:4.7 94.8 4-3 96.4:3.6 93.3 4-4 97.0:3.0 92.9

(73) As can be seen from this example, when the molar ratio of product:starting material exceeds 95:5 when the process is operated on a continuous basis, there is a notable reduction in selectivity towards the product of interest.

Example 5: Effects of Feedstock Purity

(74) These examples were carried out using the equipment and techniques as illustrated in FIG. 2, with reference to the accompanying text in Example 2 above, except where otherwise stated. Trial 5-1 is the stream obtained from stream 110.4 in FIG. 2. Trials 5-2-5-5 are alternative examples, obtained using the same apparatus and techniques, but employing feedstocks of differing purity. The data below demonstrates that although lower purity feedstock was used in trials 5-2 to 5-5, this advantageously does not significantly impact product purity when obtained from processes of the present invention.

(75) TABLE-US-00011 Trial No. Compounds 5-1 5-2 5-3 5-4 5-5 1-chlorobutane 0.004 0.028 0.032 0.011 0.002 TeCM 0.0004 0.007 0.004 0.014 0.006 1,1,1-trichloropropane 0 0 0.0005 0.004 0.009 Tetrachloroethene 0.002 0.001 0.002 0.02 0.052 1,1,3-trichloropropene 0.01 0.025 0.017 0.013 0.065 1,1,1,3- 99.96 99.81 99.92 99.89 99.836  tetrachloropropane 1,1,1,3,3- 0.0002 0.017 ND ND ND pentachloropropane Hexachlorethane 0.002 0.079 0.002 0.013 0.001 1,1,1,2,3- 0.0004 0.003 0 0.004 ND pentachloropropane Others 0.023 0.033 0.022 0.031 0.028

Example 6: CSTR and Plug Flow Combination

(76) These examples were carried out using the equipment and techniques as illustrated in FIG. 1, with reference to the accompanying text in Example 2 above, except where otherwise stated. The efficiency of reaction in the second plug-flow reactor (reference numeral 4 in FIG. 1) was evaluated. Two trials were conducted with differing amount of dissolved ethylene at the inlet of the plug-flow reactor which was operated at the same temperature, 110° C., as the main CSTR reactor (reference numeral 3 in FIG. 1). The results are shown in the following table:

(77) TABLE-US-00012 Ethylene Ethylene content at TeCM content content TeCM content plug-flow at plug-flow at plug-flow at plug-flow Trial reactor reactor reactor reactor No. inlet (%) intlet (%) outlet (%) outlet (%) 6-1 1.19 12.5 0.087 6.58 6-2 0.36 9.17 0.089 6.99

(78) As can be seen from this example, there is a conversion of ethylene between 75-93% in the plug-flow reactor. Thus if plug-flow reactor is employed there is more efficient ethylene utilization in the reaction section. The serial plug-flow reactor allows the CSTR reactor to be operated at an optimal pressure, without needing complex and uneconomical ethylene recovery processes. The serial plug reactor therefore controls the ethylene use in an efficient closed loop.

Example 7: Problematic Degradation of Catalyst Ligand During Conventional Distillation

(79) Fractional distillation equipment consisting of a 2-litre glass distillation four-neck flask equipped with condenser, thermometer, heating bath and vacuum pump system was set up. The distillation flask was initially filled with 1976 grams of reaction mixture obtained using the apparatus and techniques illustrated in FIG. 1 and explained in the accompanying text in Example 2 above.

(80) During distillation, pressure was gradually reduced from an initial pressure of 100 mmHg to a final pressure of 6 mmHg. During this period, 1792 grams of distillate (in different fractions) were extracted. During distillation, there was visible HCl gas formation and furthermore chlorobutane (the breakdown product from tributylphosphate ligand) was also formed in significant amounts namely between 1 to 19% for the distillate fractions. Upon these observations being made, the distillation was interrupted, distillation residue was weighed and analyzed and was found to have a Tetrachloropropane content of 16%. It was no longer possible to continue distillation without significant degradation of the Tributylphosphate ligand.