DD201138A5 - PROCESS FOR THE PREPARATION OF 1,2-DICHLORETHANE - Google Patents

Abstract

A process for the preparation of 1,2-dichloroethane is described. Here, in at least one reaction chamber, ethylene with chlorine, optionally in the presence of a catalyst, at 20 to 150 ° C and in at least one other reaction chamber ethylene with hydrogen chloride and oxygen, in the presence of a catalyst and optionally in the presence of inert gases, at 180 to 300 gr implemented. The gaseous reaction product from the reaction of the ethylene with chlorine is introduced after separation of the main amount of the 1,2-dichloroethane contained therein, optionally with the addition of further gas stream into the reaction space in which ethylene is reacted with hydrogen chloride and oxygen. The new process allows the cost-effective use of exhaust gas from the direct chlorination of ethylene, as well as equipment and storage vessels used in the purification of 1,2-dichloroethane. The total yield of 1,2-dichloroethane is increased.

Description

The invention relates to an improved process for the preparation of 1,2-dichloroethane according to the invention claim.

1,2-dichloroethane is produced on a large scale and mainly used for the production of vinyl chloride by thermal cleavage. For the recovery of 1,2-dichloroethane is mainly the direct addition of chlorine to ethylene in the presence of catalytic amounts of a Lewis acid, usually ferric chloride. This reaction may be carried out in the gas phase or in a liquid which usually contains predominant amounts of 1,2-dichloroethane, preference being generally given to the liquid-phase reaction.

As in the thermal cleavage of 1,2-dichloroethane to vinyl chloride forms hydrogen chloride, in addition to the direct chlorination of ethylene is also the implementation of ethylene with oxygen or air and hydrogen chloride in the presence of a mostly for its reuse

20 mostly copper-containing catalyst, a3.s below

"Oxychlorination of ethylene", carried out. Thus, a modern manufacturing plant for 1,2-dichloroethane which is to be thermally cleaved to vinyl chloride advantageously contains at least one reactor in which the direct chlorination of ethylene and at least one reactor in which the oxychlorination of ethylene is carried out. After separation of the 1,2-dichloroethane exhaust gases fall from both reactors, the environmentally harmful

Contain substances and may be released only after removal of these in the atmosphere.

Characteristic of the known technical solutions

It is mainly known from the older literature to cool the exhaust gases from the direct chlorination reactor in series heat exchangers to about -20 ⁰ C to condense 1,2-dichloroethane. The non-condensed gases are then treated in scrubbers first with water and then with alkali to remove small amounts of unreacted chlorine. The remaining gas mixture can then be used as a fuel, for example (see Chemical Engineering, March 27, 1967, page 28, right column, third paragraph).

This process is susceptible to interference, since the gases which are withdrawn from the direct chlorination reactor also contain small amounts of water vapor, which condenses on cooling to -20 ⁰ C in solid form and the heat exchangers clogged. More frequent shutters are needed to remove the blockage. In this case, 1,2-dichloroethane-containing water is obtained, which must first be cleaned before it is added to the wastewater. Although this difficulty can be eliminated if the gases from the Direktchlorierungsreaktor only to about +1 to +2 ⁰ C cooled. In this case, however, the 1,2-dichloroethane is not so completely condensed, there is an Aüsbeutverschlechterung. The exhaust gas from the condensation contains appreciable amounts of 1,2-dichloroethane, which can not be safely discharged into the atmosphere for reasons of environmental protection and therefore requires additional cleaning effort, for example activated carbon absorbers. The further purification of the exhaust gas in scrubbers is expensive.

235153 8

More recently, therefore, the exhaust gas from the direct chlorination reactors, which contains an excess of ethylene, has first been freed from most of the 1,2-diolorethan entrained by partial pressure by condensing with brine, then compressing the residual gas to the inlet pressure of the fresh ethylene and attributed to the direct chlorination reactor.

Instead of the ethylene cycle, a post-reactor can be used in which dichloroethane is kept in circulation via packing. At a suitable point, a small amount of chlorine is introduced into the liquid. The free chlorine reacts with the residual ethylene to 1,2-dichloroethane. The liquid growth is combined with the production. The remaining inert gases are released via a cleaning system (absorption or washing system) to the atmosphere (see Ullmann's Encyclopedia of Industrial Chemistry, Volume 9 (1975) page 427, right column, paragraphs 2 and 3). In particular, the process using a post-reactor is expensive, but it is applied because the exhaust gas recirculation in the Direktchlorierungsreaktor not satisfied. In this by-products of the chlorination reaction, which are located in the exhaust gas, for example, ethyl chloride, vinyl chloride, hydrogen chloride, carbon dioxide, carbon monoxide and lower saturated hydrocarbons in the system, causing chlorine loss and the reaction with chlorine other undesirable by-products are formed.

Purpose of the invention

The purpose of the invention is to provide a method which allows a low-cost elimination of the exhaust gases from the direct chlorination of ethylene, wherein advantageous

235153 8 -

also other exhaust gases, which originate from the purification and storage of 1,2-dichloroethane can be included.

5 Presentation of the essence of the invention

It is a process for the preparation of 1,2-dichloroethane, wherein in at least one reaction chamber ethylene with chlorine, optionally in the presence of a catalyst, at 20 to 150 ⁰ C and in at least one further reaction chamber ethylene with hydrogen chloride and oxygen in the presence of Catalyst and optionally under the reaction conditions of inert gases, is reacted at 180 to 300 ⁰ C, the reaction products formed are removed from the reaction chambers .werden and therefrom, the majority of the formed 1,2-dichloroethane is deposited, which is characterized in that after deposition of the 1,2-dichloroethane from the reaction products of the reaction of ethylene with chlorine remaining gas mixture, optionally with the introduction of further gas streams, is introduced into the reaction space in which ethylene is reacted with hydrogen chloride and oxygen.

The reaction of ethylene with chlorine is conveniently carried out by known methods, for example in a liquid containing a major proportion of 1,2-dichloroethane, at temperatures of 20 to 70 ⁰ C in the presence of catalytic amounts, for example 0.05 to 0.01 Wt .-%, based on the liquid, of one or more Lewis acids, for example ferric chloride. This method can also be carried out at a higher temperature, for example 83 to 85 ⁰ C, wherein the heat of reaction is removed substantially by boiling 1,2-dichloroethane. It is also possible, the reaction of ethylene with chlorine in the gas phase, under

235 153 8

Exposure of ultraviolet light or catalysts, for example, the above, make. In general, temperatures up to 150 ^° C. are customary for this purpose

 5

From the resulting in the implementation of ethylene with chlorine gases, the 1,2-dichloroethane by cooling to temperatures just above the freezing point of the water, for example +1 or +2 ° C, deposited at normal atmospheric pressure. The use of lower temperatures would, although the yield of 1,2-dichloroethane somewhat increase, but brings difficulties since the exhaust gases always contain some water, which freezes at 0 ^"0 C and lower temperatures, whereby the cooling vessels and leads can be easily clogged . drying of the exhaust gas before condensation of the 1,2 - dichloroethane is inconvenient and costly When applying the method according to the invention the exhaust gases produced by the cooling from the direct chlorination of ethylene to only about +1 to +2 ⁰ C no disadvantage since. the remaining in the exhaust gas portions of 1,2-dichloroethane the oxychlorination obviously go through unchanged and thus increase the yield of oxychlorination of 1,2-dichloroethane accordingly.

The reaction of the ethylene with hydrogen chloride and oxygen (oxychlorination) is also carried out according to known methods at 180 to 300 ⁰ C, preferably 200 to 250 ⁰ C, in the presence of a copper-containing catalyst, which may also contain alkali metal chlorides and other additives. The copper ,, usually in the form of a copper salt and optionally the alkali metal chlorides and others

235153 8

Additives are expediently adsorbed on an inert, finely divided material, for example aluminum oxide. The catalyst particles can be stacked in the reaction space as a so-called fixed bed or in fluidized form. In place of oxygen, air is generally used to improve economy. This has the further advantage, especially in the fluidized bed process, of having nitrogen available as an additional inert gas for fluidizing the catalyst particles.

The gases which escape from the reaction space after the reaction of ethylene with hydrogen chloride and oxygen or air are cooled, for example by spraying alkaline-containing water. As a result, residual hydrogen chloride is removed from the gases. Suitably, the cooling is adjusted so that the discharged at normal pressure, cooled gas has a temperature above the boiling point of 1,2-dichloroethane (about 83 ⁰ C). From the water used for cooling, dissolved 1,2-dichloroethane is removed by stripping with steam, condensed, separated from the condensed water vapor and collected with the bulk of the formed liquid 1,2-dichloroethane first in a container and from this into a distillation column for dehydration of 1,2-dichloroethane (so-called "dewatering column").

The cooled to, for example, about 90 ⁰ C main amount of gases from the oxychlorination is now cooled, for example by means of a brine cooler to a temperature which is slightly above the freezing point of the water. Here, the main amount of 1,2-dichloroethane condenses

235 153 8

and is diverted to a collection container. The non-condensed fractions are now suitably passed through an absorption system to remove most of the still existing in the gases still existing 1,2-dichloroethane from the exhaust gas. For example, absorbers of activated carbon or high-boiling, liquid, alkylated, aromatic hydrocarbons, as used, for example, under the trade name

name "Solvesso" from company Esso Chemie or "Shellsol" from company Shell are known. The exhaust gas leaving the absorber (s) can now either be reintroduced into the Qxychlorierungsreaktor, or subjected to a subsequent chlorination with subsequent separation of the formed 1,2-dichloroethane or co-fed into a combustion or be discharged as such into the atmosphere.

The 1,2-dichloroethane which accumulates in the absorption units is from time to time heated by heating the absorbent; optionally under reduced pressure, desorbed, condensed and also placed in the collection tank for 1,2-dichloroethane.

According to the invention, the exhaust gas from the direct chlorination of ethylene, which remains after cooling to a temperature just above the freezing point of the water, condensation and separation of the main amount of 1,2-dichloroethane, fed into the reaction space in the ethylene with hydrogen chloride and oxygen or air is implemented. Feeding may be with the ethylene and / or hydrogen chloride, but exhaust gases from the direct chlorination may be added elsewhere in the oxychlorination reactor. In any case, the feed should be in one place

235153 8

take place, from which the exhaust gas from the direct chlorination still flows through all or a large part of the space containing the catalyst particles.

Before being fed into the oxychlorination reactor, the exhaust gases from the direct chlorination must be brought to a pressure which is slightly above the pressure prevailing in the oxychlorination reactor at the feed point of the exhaust gases. For this purpose, if necessary, a compressor is used.

The residual gases, which remain from the reaction of ethylene with chlorine after separation of the main amount of 1,2-dichloroethane, are advantageously admixed with waste gases from distillation apparatus for purifying 1,2-dichloroethane and / or from storage vessels for 1,2-dichloroethane. Come dichloroethane, which are used following the incomplete thermal cleavage of 1,2-dichloroethane for the recovery of vinyl chloride after removal of the vinyl chloride. Such storage vessels are, for example, a vessel in which the humid 1,2-dichloroethane as obtained from direct chlorination and oxychlorination is collected, a vessel in which the dehydrated 1,2-dichloroethane is stored and a vessel in which the from the direct chlorination of ethylene in the presence of Lewis acids, such as ferric chloride, 1,2-dichloroethane is washed with water to remove catalyst residues.

Exhaust gases which originate from distillation apparatuses for purification of 1,2-dichloroethane are those which remain gaseous after condensation of the major part of the condensable fractions from the top products of the respective columns. Distillation apparatus for cleaning

235153 8-

of 1,2-dichloroethane, for example, the apparatus in which 1,2-dichloroethane is freed from water and low boilers (dewatering column), the apparatus in which 1/2-dichloroethane is separated from the high boilers (high boiler column) and the apparatus in which 1,2-dichloroethane still contained therein is distilled off from the bottom product of the high-boiling column using vacuum (vacuum column). All of these exhaust gases contain nitrogen as well as nitrogen.

A content of further gaseous substances / for example hydrogen chloride and ethylene does not disturb.The admixture of all these exhaust gases to the residual gas from the direct chlorination expediently takes place before the compression and optionally warming for the purpose of feeding into the oxychlorination reactor.

After compression of the residual gas from the direct chlorination, optionally in admixture with the exhaust gases from the apparatuses described in the preceding sections, the exhaust gases are advantageously heated before being introduced into the oxychlorination reactor at 100 to 200 ⁰ C, in particular at 150 to 180 ⁰ C. For this purpose, for example, conventional heat exchangers are used, as a heating means can advantageously be used discharged from the Oxychlorierungsreaktor gas.

In a further preferred embodiment of the method according to the invention, the gas mixture, which comes from the reaction of ethylene with chlorine and optionally further exhaust gases were admixed, analyzed for its content of hydrogen chloride and ethylene, at play sv / ei se by gas chromatography

235153 8

- ίο -

Analysis and the result of the analysis to automatically control the feeding of additional amounts of at least one of the gases hydrogen chloride, air or ethylene is used in the reaction space, are reacted in the ethylene with hydrogen chloride and oxygen. In the latter oxychlorination reactor, 1 mole of ethylene reacts with 2 moles of hydrogen chloride and one-half mole of oxygen (or five 1/2 of air) to form 1 mole of 1,2-dichloroethane and one mole of water. If the molar ratio of hydrogen chloride to ethylene is less than 2 in the exhaust gas or exhaust gas mixture fed into the oxychlorination reactor, it is expedient to add an additional amount of hydrogen chloride; if it is greater than 2, an additional amount of ethylene is expediently introduced into the oxychlorination reactor in consideration of all the gases fed into the oxychlorination reactor, a molar ratio of hydrogen chloride to ethylene of about 2 is given. In general, work is carried out with a slight molar excess of oxygen or air in excess of the stoichiometric molar amounts given above,

The new method is particularly suitable for residual gases derived from a reaction of ethylene with chlorine, which has been carried out in the presence of liquid 1,2-dichloroethane and a catalyst at 20 to 95 ⁰ C.

The process according to the invention makes possible a cost-effective use of the exhaust gases from the direct chlorination of ethylene and from apparatus and storage vessels which are used in the purification of the 1,2-dichloroethane. It also achieves a yield improvement of 1,2-dichloroethane. Another advantage is the fact that the exhaust gases from the implementation of

235 153 8

Ethylene with chlorine need not be cooled below 0 ⁰ C in order to achieve the fullest possible yield of 1,2-dichloroethane bei.gleichzeitiger, cleaning the exhaust gases, blockages of the condensing units is avoided by freezing water. In addition, variations in the operating conditions of direct chlorination of ethylene, for example variations in catalyst concentration or variations in the feed of the raw materials as well as the operating temperature, are significantly less effective on the quality and yield of 1,2-dichloroethane produced by the new process.

2351 53 8 - ¹² - Embodiments Example 1

A coolable reactor contains a liquid which consists mainly of 1,2-dichloroethane. The remainder contains mainly 1,1,2-trichloroethane in addition to other chlorinated hydrocarbons with 1 and 2 C atoms. The liquid also contains 0.02 to 0.04% by weight of ferric chloride (the concentration varies during operation within the specified limits). In the reactor, ethylene and chlorine are fed in gaseous form in a molar ratio of 1: 1.02 and the liquid is circulated. The temperature of the liquid is adjusted by cooling to 4 5 ⁰ C and held. The pressure in the reactor is 110 kPa.

By discharging a portion of the liquid, the level of liquid is maintained in the reactor. The discharged liquid is washed in a conventional washing vessel with water, separated from the washing water and stored in a first collection container. The gas mixture escaping from the reactor is cooled to + 3 ° C. in a brine cooler. The condensed liquid is also added to the first collection container. From the gas mixture leaving the brine cooler, 300 parts by weight per hour are removed and, as described below, further processed

 The liquid from the first collection vessel is fed to a distillation apparatus in which, by known methods, water and substances which boil at a lower temperature than 1,2-dichloroethane are distilled overhead and condensed together with some 1,2-dichloroethane. The condensate is passed into a second collection container and then worked up in the usual way to recover further 1,2-dichloroethane. That in the swamp of. ι ι. Column remaining product is also we¬itermeth processed by known methods to pure 1, 2-dichloroethane and this then a plant for the purpose of thermal cleavage

35 tungsten added to vinyl chloride.

235153 8

The scrubbing of the crude 1,2-dichloroethane from the reactor, in which ethylene is reacted with chlorine, the collection of the liquid in the first and second collection tanks, as well as the distillation to separate water and low boilers of 1,2-dichloroethane, are carried out under nitrogen carried out as a protective gas.

From the non-condensed off-gas of the above-described distillation apparatus, 530 parts by weight per hour are taken out. From the respective ventilation of the 1,2-dichloroethane washing container and the first and second collecting container, 20.1 parts by weight per hour of exhaust gas are taken out together. All exhaust gas withdrawals are combined. The resulting 850.1 parts by weight / h of exhaust gas are analyzed by gas chromatography. Here are the following

15 values determined.

Parts by weight / h 11.9 hydrogen 5.2 oxygen 14.7 nitrogen 336.6 Carbon monoxide 5.0 carbon dioxide 281.9 Ethan 6.0 ethylene 38.0 vinyl chloride 1.5 1,2-dichloroethane 34.5 methylene chloride 2.6 1,1-dichloroethane 1.4 ethyl 106.1 1,1-dichloroethylene 0.3 1,2-dichloroethylene-trans 0.3 1,2-dichloroethylene cis 0.3 Carbon tetrachloride 3.8 chloroform

850.1

This exhaust gas mixture is compressed to 360 kPa pressure, heated in a heat exchanger to 175 ⁰ C and fed to a reactor in which ethylene, hydrogen chloride and air are reacted in the presence of fluidized catalyst particles. The catalyst particles are composed of alumina which contains copper (II) chloride and potassium chloride. The exhaust gas mixture is introduced into the reactor below the zone in which the fluidized catalyst particles are located.

Based on the above analysis, 166.4 parts by weight / h of air and 164 parts by weight / h of hydrogen chloride are required to convert the ethylene and ethylene chloride present in the exhaust gas into 1,2-dichloroethane. The reactor is charged with the amounts of air, hydrogen chloride and ethylene given in Table 1 below in Example 1. The pressure in the reactor is 3 50 kPa, the temperature 220 ⁰ C. The gas leaving the reactor gas mixture is cooled by injecting alkaline water to 89 ⁰ C, the cooling water then stripped with steam, the resulting gaseous mixture of water and crude 1, 2-dichloroethane is condensed by cooling to 5 ⁰ C, the crude 1,2-dichloroethane separated from the water and added to the first collection container described above.

The cooled to 89 ⁰ C gas mixture is cooled in water coolers and a brine cooler to 10 ⁰ C and the thus condensed crude 1,2-dichloroethane also passed into the first collection container described above. The uncondensed gas is contacted in a gas scrubber with a mixture of alkylated benzenes, known under the trade name Solvesso. The gas leaving the scrubber is analyzed by gas chromatography. The values determined are given in Table 2 under Example 1. This exhaust gas is released into the atmosphere.

The scrubbing liquid enriched with products from the gas mixture is heated to above 100 ^° C. under reduced pressure.

235 153 8

the escaping gas condenses and the crude 1,2-dichloroethane thus obtained is added to the first collecting tank already mentioned several times above. The treated washing liquid goes back into the gas scrubber.

'5.

In addition to the values already mentioned in the previous sections, the following values are also listed in Table 1 under Example 1: The total amount of crude 1,2-dichloroethane produced in the oxychlorination reactor, the content of which is pure 1,2-dichloroethane

(determined by gas chromatography, see Table 3), the amount of pure 1,2-dichloroethane calculated therefrom, the increase of this amount compared to the comparative experiment A described below and the percentage

Sales of hydrogen chloride and ethylene.

In Table 3 below, the gas chromatographic analysis of crude 1,2-dichloroethane is listed under Example 1.

Comparative experiment A

The oxychlorination of the ethylene is carried out as described above under Example 1, with the difference that no exhaust gas is introduced into the reactor and the process parameters given in Tables 1, 2 and 3 under Comparison A 25 are used or values are found.

Example 2

The procedure is as described in Example 1 with following differences:

a) The liquid in the reactor in which ethylene is reacted with chlorine, contains 0.001 to 0.003 wt .-% of iron-III-chloride, based on the liquid (the concentration varies during operation within 35 of the specified limits).

35

b) The liquid in the reactor boils, the temperature is 84 ⁰ C.

c) By removing the gaseous 1,2-dichloroethane and condensation while keeping the filling volume of the reactor constant, the temperature is maintained at said level.

d) The condensed and removed 1,2-dichloroethane is not washed with water.

e) The condensation described under c) is continued in the brine cooler to a gas temperature of +2 ⁰ C, the non-condensed gas mixture 490 parts by weight are removed per hour. The gas chromatographic analysis of this gas mixture he gives:

Parts by weight / h nitrogen 43.8 oxygen 10,0 ' hydrogen 3.1 Carbon monoxide 4.4 carbon dioxide 138.4 Ethan 4.7 ethylene 229.3 ethyl 10.1 1,2-dichloroethane 46.2

490.0

This gas mixture is compressed to 3 60 kPa without admixing other exhaust gases, heated in a heat exchanger to 150 ⁰ C and as described in Example 1, fed to the reactor in which ethylene, hydrogen chloride and air in the presence of fluidized catalyst particles are reacted.

235 153 8

^Because of the above analysis, 665.6 parts by weight / hr air and 574 parts by weight / h of hydrogen chloride are used for transfer of the exhaust gas present in the ethylene and ethyl chloride in 1,2-dichloroethane needed.

f) The oxychlorination reactor is operated at 350 kPa and a temperature of 230 ⁰ C with the listed in Table 1 under Example 2 amounts of air, hydrogen chloride and ethylene. The work-up of the reaction products is carried out as in Example The values determined for crude 1,2-dichloroethane, pure 1,2-dichloroethane and the conversions are also given in Table 1 under Example 2.

The analysis of the crude 1,2-dichloroethane is shown in Table 3, that of the exhaust gas from the oxychlorination in Table 2, each under Example 2.

Comparative experiment B

The oxychlorination of the ethylene is carried out as described above under Example 2, with the difference that no exhaust gas is introduced into the reactor and the process parameters given in Tables 1, 2 and 3 under Comparison B are used or values are found. ·

Example 3

The procedure is as described in Example 1 with the following differences:

a) The temperature of the liquid in the reactor, in which ethylene is reacted with chlorine, is 35 ⁰ C and is maintained by cooling at this level. '

b) From the gas mixture leaving the brine cooler,

Are removed 422 parts by weight per hour. The gas chromatographic analysis of this gas mixture gives:

™ "% J sJ I lj> J

Parts by weight / h

Nitrogen 174.4

Oxygen 11.9

Hydrogen 3.5

Carbon Monoxide 4.1

Carbon dioxide 148.5

Hydrogen chloride 7.9

Ethylene 15.0

Ethyl chloride 8.2

1, 2-dichloroethane 40.9

422.0

This gas mixture is compressed without admixing further exhaust gases and without heating to 360 kPa and, as described in Example 1, fed at a temperature of 30 ⁰ C to the reactor in which ethylene, hydrogen chloride and air in the presence of fluidized catalyst particles are reacted. According to the above gas chromatographic analysis, the supply of hydrogen chloride and air to the oxychlorination reactor is auto-

20 mechanically controlled.

c) The oxychlorination reactor is operated at 350 kPa and a temperature of 190 ⁰ C with the listed in Table under Example 3 amounts of air, hydrogen chloride and ethylene. The workup of the reaction products is carried out as in Example The values determined for crude 1,2-dichloroethane, pure 1,2-dichloroethane and the conversions are also given in Table 1 under Example 3. The analysis of the crude 1,2-dichloroethane is shown in Table 3, that of the exhaust gas from the oxychlorination in Table 2, each under Example 3.

235153 8

Comparative experiment C

- 19 -

The oxychlorination of the ethylene is carried out as described above under Example 3, with the difference that no exhaust gas is introduced into the reactor and the process parameters given in Tables 1, 2 and 3 under Comparison C are used or values are found.

Example 4

The procedure is as described in Example 1, with the following differences:

a) The liquid in the reactor, in which ethylene is reacted with chlorine, contains 0.001 to 0.003 wt .-% ferric chloride, based on the E'lüssigkeit (the concentration varies during operation within the specified limits).

b) The liquid in the reactor boils, the temperature is 145 ⁰ C, the reactor operates under pressure.

c) By removing the gaseous 1,2-dichloroethane and condensation while keeping the filling volume of the reactor is kept constant, the temperature in the reactor at 145 ⁰ C.

d) The condensed and removed 1,2-dichloroethane is not washed with water.

e) The condensation described under c) is carried out in the 30-brine cooler up to a gas temperature of +2 ⁰ C

the non-condensed gas mixture is expanded, mixed with further flue gases from containers of the 1,2-dichloroethane storage and further processing, and the resulting 842.5 parts by weight are analyzed by gas chromatography. The following values are determined here:

Wt .-% - parts / h nitrogen 70.3 oxygen 13.4 hydrogen 3.4 Carbon monoxide 4.7 carbon dioxide 117.6 Ethan 12.8 ethylene 542.4 ethyl 9.1 1,2-dichloroethane 68.8

¹⁰ 842.5

This gas mixture is compressed to 360 kPa, heated in a heat exchanger to 190 ⁰ C and, as described in Example 1, fed to the reactor in which ethylene, hydrogen chloride and air in the presence of fluidized catalyst particles are reacted. From the above analysis, to convert the ethylene and ethyl chloride present in the exhaust gas into 1,2-dichloroethane, 1216 parts by weight / h of air and 1394

20 parts by weight / h of hydrogen chloride needed.

f) The oxychlorination reactor is operated at 350 kPa and a temperature of 280 ⁰ C with the listed in Table 1 under Example 4 amounts of air, hydrogen chloride and ethylene. The workup of the reaction products is carried out as in Example 1. The values determined for crude 1,2-dichloroethane, pure 1,2-dichloroethane and the conversions are also given in Table 1 under Example 4. The analysis of the crude 1,2-dichloroethane is shown in Table 3, that of the exhaust gas from the oxychlorination in Table 2, each under Example 4.

235153 8

Comparative experiment D

- 21 -

The oxychlorination of the ethylene is carried out as described above under Example 4, with the difference that no exhaust gas is introduced into the reactor and the process parameters given in Tables 1, 2 and 3 under Comparison D are used or values are found.

Table

Process conditions and determined product values in the oxychlorination of Ethyl ens

Comparison Example Comparison Example Comparison Example Comparison Example A 1 B 2 C 3 D

46 920 47 086 <* 6 920 47 586 t6 850 46 882 47 042 48 258 31 240 31 404 31 650 32 224 31 158 31 200 31 158 32 552 12 530 12 580 12 580 12 580 12 310 12 310 12 310 12 310 220 220 230 230 190 190 280 280

Parts by weight / h HCl parts by weight / h CJi parts by weight / h temperature C

exhaust gas exhausted .. __ __ __ ^ __

uev.-ieile / n

Crude 1,2-dichloroethane, ^ ^ ^ _m ^ ^ _{Q m} ^ _m ^ _{Q 5} ^ ^ ^ _m

parts by weight of 1,2-dichloroethane,. pure 1,2-dichloroethane, parts by weight / h

Increase of 1,2-dichloroethane in parts by weight and percent

Sales of HCl:

Let _£ at2 C ₂ H ₄

to crude 1,2-dichloroethane to CO ₂

C ₁ H, unchanged in the exhaust gas

i) sales similar to the corresponding comparative experiment A or B, C or D, determination inaccurate weger, admixtures from the exhaust gas supplied

99, 119 99 , 065 98.969 98.960 99, 225 99 , 201 97.053 96 , 954 > 41 595 41 870 42,130 42 950 40 680 40 765 40 210 41 575 to NJ - η 275 0.66? ~ 820 -1.95? - _m 85 0.2? - 1 365 3.4? I 99.6% 99.6? 99.7? 99.7? 97.7? 97.8? 99.8? 99.8? 94.2? D 95.3? D 9 ^ 2? D 93.3? D 2 <ί 1.95? 1.9? 5.3? 1.2 % 0.90? 0.7? 0.2? 2.3 % fin Vi <f Ιϋϋ, Οϋ % 3.2 % 00,00? 1 _t 2 % 100.00?

TABLE 2

Analysis of exhaust gas from oxychlorination after washing

Comparison A Example 1 'Compare Example 2 Comparative Example 3 Comparison D Example 4 Vol. Vol.-2 vol. Vol? Vol? VoT.-? Vol? Vol?

° 2 6.3 6.2 6.5 6.4 7.3 7.3 1.2 1.3 CO 0.76 0.76 0.56 0.57 0.46 0.43 0.2 0.25 CO ₂ 1.45 1.86 1.25 1.46 1.15 1.28 4.0 4.4 ^C A 0.72 0.71 0.58 0.58 1.01 1.05 0.44 0.41 ^C 2 ^H 6 "<0.01 0.01 <0.01 0.01 <0.01 0.02 <0.01 0.01 vinyl chloride 0.0020 0.0024 0.0018 0.0020 0.0020 0.0021 0.0129 0.0099 C ₂ H ₅ Cl ' 0.00 " 0.0366 0.0040 0.0056 0.0045 0.0090 0.0081 0.0102 1,2-dichloroethane 0.0001 0.0002 0.0002 0.0001 0.0001 0.0001 0.0001 0.0001

TABLE 3

Analysis of crude 1,2-D produced in oxychlorination ^; chloroethane

Comparison A Example 1 Comparison Weight? % By weight %

Example 2 Comparative Example 3 C D Comparative Example 4 part by weight α Gew.4 wt -.% Wt -.% Wt -.%

H ₂ O 0.192 0,190 0.196 0.194 0,190 0.188 0.192 0.184 Sun.e C ₂ H ₂ ; C ^; C ^ 0.009 0.009 0,007 0,007 0,008 0.009 0,002 0,002 vinyl chloride 0,002 0,002 0,002 0,002 0,002 0,002 0.024 0.028 C ₂ H Cl 0,008 0.031 0,007 0.011 0,008 0,014 0.098 0,102 ethylene oxide 0,003 0,003 0,003 0,003 0,003 0,003 0,003 0,003 1,2-di-chloroethylene trans 0.00? 0,002 0,002 0,002 0,002 0,002 0.056 0.054 1,1-dichloroethane 0,0Oi. 0,007 0.005 0.005 0.005 0.005 , 0,008 0,007 Cl. 4 0.091 0,099 0,127 0,125 0.078 0.086 0.112 0.132 1,2-cis-Oichlorethylen "0.008 0,008 0,010 0.011 0,008 0,006 0.103 0.098 CH Cl ₃ 0,107 0,134 0.121 0,122 0,128 0,117 0,124 0,134 1,1,2-trichlorethylene 0.005 0.005 0.001 0,004 0,002 0,003 0,020 0,018 1,2-dichloroethane 99.119 99.065 98.969 98.960 99.225 99.201 97.053 96.954 Teirachloreihylen 0,018 0,018 0,018 0.019 0,014 <0.010 0,035 0.043 1,1,2-Tnchlorethan 0,397 0.394 0.493 0,496 0.307 0.335 1,386 1,669 Eihylenchlorhydrin 0.01 k 0,013 0,013 0,013 0,008 0.009 0,075 0.088 Tei ^ ar.hloreihan 0,021 0,020 0,025 0.026 0,015 0.023 0.532 0.487

Claims (5)

invention claim 1. A process for the preparation of 1,2-dichloroethane, wherein in at least one reaction chamber ethylene with chlorine, optionally in the presence of a catalyst, at 20 to 150 ⁰ C and in at least one further reaction space ethylene with hydrogen chloride and oxygen in the presence of a catalyst and optionally is reacted under the reaction conditions of inert gases, at 180 to 300 ⁰ C, the reaction products formed are removed from the reaction chambers and from the main amount of the formed 1,2-dichloroethane is deposited, characterized in that after deposition of the 1,2-dichloroethane from the reaction products of the reaction of the ethylene with chlorine remaining gas mixture is optionally introduced with the introduction of further gas streams in the reaction space, in which ethylene is reacted with hydrogen chloride and oxygen. 2. The method according to item 1, characterized in that the gas mixture from the reaction of ethylene with chlorine before being fed into the reaction space in which the reaction of ethylene with hydrogen chloride and oxygen takes place, is heated to 100 to 200 ⁰ C. 3. The method according to item 1 or 2, characterized in that the gas mixture from the reaction of ethylene with chlorine still exhaust gases are added, which originate from distillation apparatus for the purification of 1,2-dichloroethane and / or from storage vessels for 1,2-dichloroethane , which are used following the incomplete thermal cleavage of 1,2-dichloroethane to obtain vinyl chloride after removal of the vinyl chloride. 4 ". Process according to any one of items 1 to 3, characterized in that the gas mixture is derived from a reaction of ethylene with chlorine carried out in the presence of liquid 1,2-dichloroethane and a catalyst at 20 to 95 ^° C. 5. The method according to any one of items 1 to 4, characterized in that the gas mixture from the reaction of ethylene with chlorine is analyzed for its content of hydrogen chloride and ethylene and the analysis result for the automatic control of the feeding of additional amounts of at least one of the gases hydrogen chloride , Air or ethylene is used in the reaction space in which ethylene is reacted with hydrogen chloride and oxygen.