DD201582A5 - PROCESS FOR THE PREPARATION OF 1,2-DICHLORETHANE - Google Patents

Abstract

A process is described for the preparation of 1,2-dichloroethane by direct chlorination and oxychlorination of ethylene in a common reaction space in time or in space successively at 180 to 300 degrees C and 0.1 to 1.1 MPa pressure in the presence of fluidized catalyst particles with removal of Reaction heat through indirect cooling. From 98 to 40% of the total amount of ethylene fed is introduced to the zone where the first chlorination reaction, for example oxychlorination, takes place, and from 2 to 60% of the total amount of ethylene fed is introduced to the zone where the second chlorination reaction, for example the direct chlorination takes place. The process makes it possible to produce the 1,2-dichloroethane required for vinyl chloride production in a reaction space with complete reuse of the hydrogen chloride and to obtain good usable heat with uniform reaction.

Description

The invention relates to a process for the preparation of 1, .2-dichloroethane, wherein ethylene is reacted with hydrogen chloride, oxygen-containing inert gases and chlorine in a common reaction space in the presence of a catalyst.

1,2-dichloroethane has been industrially produced for a number of years. It is mainly converted by thermal decomposition to vinyl chloride, which in turn is the basis for the bulk plastic polyvinyl chloride. This use has made 1,2-dichloroethane one of the most widely produced aliphatic chlorinated hydrocarbons. For its production are a number of different

15 methods are known, most of which are ethylene

out. In general, elemental chlorine is attached directly to ethylene, which is often carried out at temperatures of 40 to about 120 ⁰ C in the liquid phase in 1,2-dichloroethane. In a much used form of this process, the considerable amount of heat resulting from the chlorine accumulation is removed by boiling 1,2-dichloroethane. Since the boiling point of 1,2-dichloroethane at normal atmospheric pressure is about 84 ⁰ C, the temperature level at which the

25 amount of heat is dissipated, either not out to

To produce water vapor or it can be obtained water vapor only at low temperature and thus low pressure level, which is limited to reuse the energy contained in it.

237627 3

For better utilization of the heat of reaction of the direct chlorine addition to ethylene, it is known to carry out the reaction in the gas phase in the presence of a fluidized catalyst and immediately thereafter to split the formed 1/2-dichloroethane to vinyl chloride. The catalyst particles act as heat transferers, it is at temperatures of 370 to 540 ⁰ C and pressures up to 2.2 MPa, preferably at 0.45 to 1.85 MPa worked. The hydrogen chloride resulting from the cleavage of 1,2-dichloroethane is used in a separate apparatus for the oxychlorination of ethylene. The 1,2-dichloroethane obtained therefrom is returned to the fluidized bed cleavage reactor.

Disadvantages of the process, such as the formation of considerable amounts of ethylene chloride, relatively large amounts of unreacted 1,2-dichloroethane in the cleavage products, difficulties in controlling and controlling the process, tendency to form unwanted polychlorinated hydrocarbons and gumming and coking of the cleavage reactor to be reduced when instead of, for example, dehydrochlorination catalysts, fluidized non-catalytic solids are used in the reactor. Further, the chlorine in the chlorination reaction zone must be introduced in a controlled manner at a number of different sites to reduce the risk of coking. For this purpose, a special, relatively expensive installation in the fluidized bed cleavage reactor is erforderlieh. There is also the difficulty as far as possible to completely separate the hot cracking gases from the fluidized, finely divided, solid heat transfer medium, and the disadvantage that in these methods not the industrially preferred tube gap furnace for liquid or gaseous 1,2-dichloroethane can be used, the high throughput allows.

237 627 3

There is also known a process for the preparation of 1,2-dichloroethane, wherein in a first stage excess ethylene, hydrogen chloride and excess oxygen in the form of air in the presence of a known oxychlorination catalyst by adjusting the proportions of the starting materials to more than 90% conversion be reacted with hydrogen chloride at 180 to 350 ⁰ C and the residual gases from this stage after washing out the unreacted chlorinated water and the consequent condensation of much of the resulting 1,2-dichloroethane in a second stage with 80 to 120 mol% Chlorine, based on the ethylene used in this stage, in the presence of an iron-containing catalyst at 80 to 250 ⁰ C are reacted.

A similar process also operates ¹ in two separate stages, between which 1,2-dichloroethane and water are separated from the reaction product, wherein in the second stage, the excess ethylene from the oxychlorination with chlorine at a temperature of 80 to 320 ⁰ C in the presence an activated alumina catalyst is reacted.

It has recently been known to reduce the considerable amounts of 2-chloroethanol formed during the rechlorination of the excess ethylene from the oxychlorination by carrying out the reaction in the presence of added hydrogen chloride.

Finally, a method is known, the by-products in the chlorination of ethylene-containing gases obtained by the oxychlorination and separation of the bulk of the organic products formed by quenching with water, thereby reducing the chlorination in the presence of copper (II) chloride and / or ferric chloride on a support as a catalyst.

237627 3

All these latter methods have the disadvantage,. that an additional reactor with product separator and other facilities is needed to improve the yield of 1,2-dichloroethane, based on the ethylene used in the oxychlorination.

Purpose of the invention

The purpose of the invention is to provide a process by which both the oxychlorination and the direct chlorine addition of ethylene in a common reaction space with good yields of 1,2-dichloroethane can perform, the temperature level of the reaction a much better utilization of discharged Reaction heat of the chlorine addition to ethylene allows as by the much-used method of chlorination in boiling 1,2-dichloroethane.

Explanation of the essence of the invention

The technical object of the invention is to develop a method which is commensurate with the purpose of the invention. This object is achieved by a process for the preparation of 1,2-dichloroethane from ethylene by reaction with hydrogen chloride and oxygen-containing inert gases at 180 to 300 ⁰ C and 0.1 to 1.1 MPa and by reaction with chlorine in the gas phase in Presence of a copper or copper and iron salt-containing solid catalyst with subsequent cooling and separation by distillation of the reaction mixture, wherein both chlorination reactions in a common reaction space containing fluidized catalyst particles are carried out in succession, and the heat formed in the entire reaction space by indirect cooling with a liquid and / or gaseous Wärmeübertragußgsmedium is discharged, which is characterized in that 98 to 40% of the total amount of introduced into the common reaction space ethylene volume is introduced into the zone of the reaction space in which the first chlorination reaction takes place.

237 62 7 3

There is also known a process for the preparation of 1,2-dichloroethane, wherein in a first stage excess ethylene, hydrogen chloride and excess oxygen in the form of air in the presence of a known oxychlorination catalyst by adjusting the proportions of the starting materials to more than 90% conversion be reacted with hydrogen chloride at 180 to 350 ⁰ C and the residual gases from this stage after washing out the unreacted chlorinated water and the consequent condensation of much of the resulting 1,2-dichloroethane in a second stage with 80 to 120 mol% Chlorine, based on the ethylene used in this stage, in the presence of an iron-containing catalyst at 80 to 250 ⁰ C are reacted.

A similar process also operates in two separate stages, between which 1,2-dichloroethane and water are separated from the reaction product, wherein in the second stage the excess ethylene from the oxychlorination with chlorine at a temperature of 80 to 320 ⁰ C in the presence of a activated alumina catalyst is reacted.

It has recently been known to reduce the considerable amounts of 2-chloroethanol formed during the rechlorination of the excess ethylene from the oxychlorination by carrying out the reaction in the presence of added hydrogen chloride.

Finally, a method is known, the by-products in the chlorination of ethylene-containing gases obtained by the oxychlorination and separation of the bulk of the organic products formed by quenching with water, thereby reducing the chlorination in the presence of copper (II) chloride and / or ferric chloride on a support as a catalyst.

237627 3

All these latter methods have the disadvantage that an additional reactor with a product separator and other facilities is required to improve the yield of 1 , 2-dichloroethane, based on the ethylene used, at • 5 oxychlorination.

Purpose of the invention

The purpose of the invention is to provide a process with which one can carry out both the oxychlorination and the direct chlorine addition of ethylene in a common Reaktiönsraum with good yields of 1,2-dichloroethane, the temperature level of the reaction a much better utilization of discharged Reaction heat of the chlorine addition to ethylene allows as by the much-used method of chlorination in boiling 1,2-dichloroethane.

Explanation of the essence of the invention

The technical object of the invention is to develop a method which is commensurate with the purpose of the invention. This object is achieved by a process for the preparation of »1,2-dichloroethane from ethylene by reaction with hydrogen chloride and oxygen-containing inert gases at 180 to 300 ⁰ C and 0.1 to 1.1 MPa and by reaction with chlorine in the gas phase in Presence of a copper or copper and iron salt-containing solid catalyst with subsequent cooling and separation by distillation of the reaction mixture, wherein both chlorination reactions in a common reaction space containing fluidized catalyst particles are carried out in succession, and the heat formed in the entire reaction space by indirect cooling with a liquid and / or gaseous. Wärmeübertragußgsmedium is discharged, which is characterized in that 98 to 40% of the total amount of ethylene introduced into the common reaction space volume is introduced into the zone of the reaction space in which the first chlorination reaction takes place.

23 7 62 7 3

and the remaining 2 to 60% of the total amount of ethylene introduced into the common reaction space is introduced into the zone of the reaction space in which the second chlorination reaction takes place.

The two Chlorierun.gs reactions can be carried out sequentially in any order, with a high-quality 1,2-dichloroethane is obtained in good Äusbeuten even if the converted amount of ethylene in each chlorination reaction is about the same size. The latter method is a preferred variant of the method according to the invention, when the produced 1,2-dichloroethane is subsequently reacted as usual by thermal cleavage to vinyl chloride, since in this way the total amount of 1,2-dichloroethane to be cleaved is produced in a reaction unit with good heat utilization can be, wherein the hydrogen chloride produced by the cleavage process in the 1,2-dichloroethane production is recycled and used for the chlorination of about half of the total ethylene used.

As a heat transfer medium for the removal of the heat generated in the entire reaction chamber by indirect cooling, for example, high-boiling mineral oils and silicone oils are. Preference is given to using water, which is converted by heat absorption into medium-pressure steam

 30

In a preferred embodiment of the process according to the invention, the inert gas containing oxygen, a first portion of ethylene and the hydrogen chloride and then the second portion of ethylene and chlorine are introduced into the reaction space in the following molar ratios:

237627 3 -

6 -

2 moles of HCl; 1.01 to 3 moles of C2H4 (total); at least 0.5, generally 0.5 to 1 mol of O ₂ and 0.009 to 2 moles of Cl ₂ , wherein the amount of chlorine is such that in the final product of the reaction, that is in the gas mixture leaving the reaction space, less than 0.001 wt .-% free, elemental chlorine can be found.

The total amount of ethylene of 1.01 to 3 mols indicated in the preceding paragraph is divided so that 98 to 40% of this total amount, preferably

95 to 60% of this total amount, ^ together with the chlorine ^"1 is hydrogen or be initiated in the immediate vicinity of the reaction chamber. The remaining 2 to 60%, preferably 5 to 40% of the total amount of the ethylene is close, advantageously short For example, if the total amount of ethylene introduced into the reaction space in a given time is 2 mols, 98 to 40%, that is, 1.96 to, is introduced into the reaction space 0.8 mol, preferably 95 to 60%, which is 1.9 to 1.2 mol, ethylene introduced together with the hydrogen chloride and 2 to 60%, that is 0.04 to 1.2 mol, preferably 5 to 40% , which are 0.1 to 0.8 irtol, ethylene is introduced into the reaction chamber shortly before chlorine is introduced, and less than 40% of the total amount of ethylene is introduced together with or in the immediate vicinity of the hydrogen chloride Decrease in the yield of 1,2-dichloroethane and increased formation of undesirable by-products.

Inert gas is understood as meaning those substances which are gaseous under the reaction conditions and participate in the reaction either not at all or in a very minor degree. Examples for. Inert gases are nitrogen, carbon dioxide and 1,2-dichloroethane.

237627 3

Steam. Nitrogen is preferably used as the inert gas. The amount of inert gas is suitably dimensioned so that a sufficient fluidization of the solid catalyst particles is achieved without diluting the reaction mixture too much.

Preferably, the oxygen to at least 50 to 100%, in particular 90 to 100%, of its total amount is introduced as air in the reaction space.

All gases are added as possible with low relative humidity in the reaction zone. The hydrogen chloride gas is preferably derived from the thermal cleavage of 1,2-dichloroethane to produce vinyl chloride. Before entering the reaction space, the gases can be preheated to temperatures of 60 to 180 ⁰ C, for example.

All gases can be individually, the ethylene introduced in at least two subsets in the reaction space, but preferably hydrogen chloride and a first portion of ethylene on the one hand and oxygen and inert gas, for example as air, on the other hand, in each case in mixture, introduced. The chlorine can be introduced in the intermittent driving time, in the preferred continuous driving manner spatially after the input of the other gases in the reaction space. Convenient ^: just before the introduction of chlorine, the second part of the ethylene is fed into the reaction space.

The reaction space may have, for example, spherical, ellipsoidal or cylindrical shape, it should be formed so that it has no dead corners and angles, in which the fluidized catalyst

237627 3

can settle. Preferably, an elongate cylindrical reaction space with a circular cross-section and a vertical cylinder axis, for example a pipe, is used.

The reaction space is expediently equipped with a double jacket and internals through which the heat transfer medium flows. Suitable internals are, for example, snake or tube register cooler. These internals can be arranged in several, separate units, which can be flowed through by different media with different flow velocities, in order to allow optimal heat utilization and an optimal temperature profile in the reaction space.

15 lent.

The various gases can be passed through simple tubes into the reaction space, which conveniently contain at their ends facilities for better distribution over the area. Such suitable means are, for example, perforated plates or balls, frits, or one or more tubes having a plurality of gas outflow openings.

The reaction space expediently contains in its uppermost zone an opening with a controllable cross section through which the reaction products are removed. After leaving the reaction space, the reaction products pass suitably a finely divided, solid catalyst particles, such as a cyclone or similar apparatus. The deposited particles are returned to the reactor.

After leaving the separator, the gases are optionally washed and partially condensed, at atmospheric pressure at about 10 ⁰ C non-condensable gas components

237 62 7 3

are passed into the atmosphere, optionally after removal of harmful or interfering substances. At least some of the non-condensable gases can also be recirculated to the reaction space. The condensed reaction products are separated by distillation to obtain pure. 1, 2-dichloroethane, as usual.

In a particularly preferred embodiment of the present invention, the substances to be reacted are introduced into the reaction space in the following proportions:

2 moles of HCl; 1.8 to 2.2 moles of C ₂ H ₄ (total); 0.5 to 0.6 mol of O ₂ and 0.79 to 1.2 mol of Cl ₂ , wherein the amount of chlorine is so dimensioned that found in the gas mixture leaving the reaction space, less than 0.001 wt .-% free, elemental chlorine become. When these molar ratios are used, 1,2-dichloroethane can be prepared for the subsequent cleavage to vinyl chloride with optimum utilization of the hydrogen chloride recirculated from the cleavage process and the feedstock ethylene and chlorine in a single reaction unit.

As described above, the total amount of ethylene is divided from 1.8 to 2.2 moles so that 98 to 40% of this total amount, preferably 95 to 60% of this total amount, together with the hydrogen chloride or in its immediate vicinity are introduced into the reaction space , The remaining 2 to 60%, preferably 5 to 40%, of the total amount of ethylene are fed into the reaction space in the vicinity, expediently shortly before the point at which chlorine is introduced into the reaction space.

The process described in the two preceding paragraphs is in particular carried out so that at one end of a tubular reactor, suitably at the bottom

237627 3

- ίο -

At the end of a vertical or nearly vertical tubular reactor, a first portion of the ethylene, hydrogen chloride and oxygen-containing inert gas are introduced separately or at least partially separated from each other. For example, the first portion of ethylene and hydrogen chloride may be introduced together / separately from the oxygen-containing inert gas. At a certain distance from the last in gas flow direction of the above-mentioned gas discharges chlorine and expediently shortly before the second portion of the ethylene introduced into the reaction space. The position of the chlorine inlet is chosen so that between it and the previous hydrogen chloride introduction is a reaction space / 40 to 85%, preferably 55 to. 75% / of the total available reaction space in the reactor. At the other end of the reactor, suitably at the top of a vertical or nearly vertical tubular reactor, the reaction products are removed.

Such a method is particularly suitable for the technically important continuous operation. For this continuous operation with hydrogen chloride initially introduced in the flow direction of the gases and subsequently introduced chlorine, the heat transfer medium is preferably passed in the indirect cooling of the reaction space in countercurrent to the gases present in the reaction space. This results in better heat dissipation and a more favorable temperature

30 course reached in the reaction space.

According to a further preferred embodiment of the process according to the invention, inert gas, which may optionally contain oxygen, as well as a first portion of the ethylene and separately from it chlorine and subsequently hydrogen chloride, are first introduced into the reaction space,

237 62 7 3

- 11 -

the second portion of the ethylene and optionally oxygen and inert gas introduced in the following molar ratios:

2 riiol C ₂ H ₄ (total); 0.9 to 1.2 niol Cl ₂ ; 1.6 to 2.3 moles of HCl and 0.35 to 1.3 moles of total O ₂ , wherein the amount of oxygen or hydrogen chloride is so dimensioned that in the final product, that is in the gas mixture leaving the reaction space, less than 0.001 wt .-% free, elemental chlorine can be found.

The total of 2 moles of ethylene used in a given time are divided so that 98 to 40% of this total amount in the immediate vicinity of the chlorine introduction into the reaction space are introduced. The remaining borrowed 2 to 60% of the total ethylene amount are fed either together with the hydrogen chloride or in its immediate vicinity in the reaction space.

This embodiment of the method is used in particular if, for example, to reduce the proportion of 2-chloroethanol in the reaction products, with a slight excess of hydrogen chloride to be driven. As already described above, this embodiment is also suitable for producing 1,2-dichloroethane for the thermal cleavage to vinyl chloride, with optimum utilization of the hydrogen chloride produced in this cleavage, wherein the entire 1,2-dichloroethane production takes place in a single reaction space.

As inert gas, in turn, as described above, for example, nitrogen, carbon dioxide and / or 1,2-dichloroethane vapor are suitable, preferably nitrogen is used. The main amount of the required sour substance is expediently supplied at the point at which

237627 3

- 12 -

Also, the hydrogen chloride is introduced, but also the supply of considerable amounts of oxygen is already at the point at which a first subset of ethylene and chlorine are introduced possible. This procedure is used in particular when air is to be used as a cost-effective fluidizing gas.

That described in the previous four paragraphs

In particular, the process is carried out so that at one end of a tubular reactor, advantageously at the lower end of a vertical or nearly vertical tubular reactor, a first portion of the ethylene, chlorine and inert gas, optionally containing oxygen, are introduced at least partially separated from each other , For example, the Inertfs® may also be introduced in admixture with chlorine but the first subset of the ethylene separate therefrom. At a certain distance from the last in the gas flow direction of the above-mentioned gas discharges hydrogen chloride and optionally oxygen and inert gas is separated or at least partially introduced separately into the reaction space. The location of the hydrogen chloride introduction is chosen so that between her and the previous introduction of chlorine is a reaction space which is 10 to 40%, preferably 15 to 30%, of the total available reaction space in the reactor. The second portion of the ethylene is introduced together with the hydrogen chloride or in its immediate vicinity in the reaction space. At the other end of the reactor, expediently at the upper end of a vertical or nearly vertical tubular reactor, the reaction products are removed.

23 7 62 7 3

- 13 -

In the embodiment of the new process just described, the heat transfer medium in the indirect cooling of the reaction space is advantageously conducted in cocurrent to the gases.

⁵

The inventive method is advantageously carried out at temperatures of the reaction mixture in the reaction space of up to 250 ⁰ C, in particular at 200 to 230 ° C. In this case, in particular in continuous processes, a spatial temperature gradient can be used. For example, the introduction point of the gases into the reaction space may be lower than at the point of removal of the reaction products. The temperature may also be higher in the first third of the reaction space when viewed in the direction of flow of the gases, or higher in the middle or in the second third than in the remaining regions of the reaction space.

Suitably, the gases are heated to temperatures of 50 to about 180 ⁰ C prior to introduction into the reaction space.

The new process can be carried out at normal atmospheric pressure (0.09 to 0.1 MPa). In general, to increase the space-time yield, elevated pressure up to about 1.1 MPa will be used. Preference is given to operating at pressures of 0.3 to 0.6 MPa.

The solid catalyst is advantageously used in finely divided form having an average particle size of 20 to 400 p.m. Particularly good results are obtained with a catalyst having an average particle size of 30 to 70 μΐη.

237627 3

The catalyst expediently consists of a carrier substance which has a large surface area per unit weight, for example 70 to 200 m ² / g and more, is mechanically stable at high temperatures, for example up to at least 500 ^° C., and remains unchanged from the gas reaction. Suitable support materials are heat-resistant oxides, for example silicon dioxide or aluminum oxide, and also diatomaceous earth or silicate materials.

On this support material is suitably about 0.5 to 15 wt .-%, based on the total catalyst, copper applied as a salt or oxide. These copper salts or oxides usually change during use by the presence of hydrogen chloride and the chlorine in copper (II) chloride, unless they have been applied from the outset as this chloride.

In addition to copper, the catalyst may advantageously be even smaller amounts of Lewis acids, in particular about 0.01 to 0.5 wt .-%, based on the total catalyst, iron, which was applied as an oxide or salt and during the reaction into the Lewis acid iron (III) chloride, contains .. The abovementioned percentages refer to the metal ion, not to the chloride or other metal salt or oxide.

In addition to the additives mentioned, the catalyst may contain further additives which reduce the volatility, in particular of cupric chloride, for example alkali metal chlorides, such as potassium chloride or alkaline earth metal chlorides, such as calcium chloride or magnesium chloride, and additives of other metallic compounds which increase the effectiveness and / or selectivity of the catalyst Improve catalyst with respect to the recovery of 1,2-dichloroethane. Examples include silver, zinc, chromium,

237 62 7 3

- 15 -

Manganese, rare earth metals such as cerium, lanthanum, ytterbium and neodymium; Platinum metals such as rhodium, platinum.

Mixtures of various catalyst and catalyst support particles may also be used, for example, copper salt treated support material mixed with particles of the untreated or another, for example, ferric chloride or other Lewis acid treated support material.

The ratio of the total reaction space before filling the catalyst to the bulk volume of the charged catalyst is suitably about 1.1 to 3, preferably 1.2 to 1.7.

 15 '' '' '.'

The flow rate of the gases in the reaction space is suitably so high that at least 95 wt .-%, preferably 100 wt .-%, catalyst particles are fluidized. Accordingly, the feed of the optionally circulated inert gas is to be selected taking into account the gases which are fed into the reaction space and participate in the reaction.

The average residence time of the gases in reaction in the reaction space depends on the chosen reaction temperature, wherein in general the residence time should be shorter the higher the reaction temperature is set. The average residence time is generally 10 to 100, preferably 20 to 70 s, and in particular 30 to 60 s. It is determined during continuous operation from the volume of the gases fed into the reaction space in one second at the pressure and the temperature prevailing in the reaction space with respect to the volume of the entire reaction space, minus the intrinsic volume of the catalyst contained therein and the internals ( Cooling tubes, temperature sensor). The

237627 3

- 16 -

The intrinsic volume of the catalyst particles is determined, for example, by the liquid displacement method (see below). .

Preferably is introduced in the invention process so much oxygen or oxygen-containing inert gas into the reaction chamber that the gas mixture leaving the reaction space after condensation of the readily condensable reaction products (for example, water and 1,2-dichloroethane) at +10 ⁰ C and separation of the Hydrogen chloride are still contained 2 to 9, in particular 4 to 7 vol .-% oxygen by conventional washing. For example, with regard to scrubbing the exhaust gases with organic, combustible solvents to remove residual amounts of 1,2-dichloroethane, it is advantageous that the O "content of the exhaust gas pretreated as described above is not too high, for example less than 9 vol. %, lies. If such a post-purification is not provided, the oxygen content may also be higher, for example 10 to 13% by volume, with very good yields of 1,2-dichloroethane still being achievable.

The separation and purification of the gas leaving the reaction space gas mixture, as already described above, according to known methods.

As also indicated above, the process of the invention makes it possible, on the one hand, to react ethylene in a single reaction unit with a particularly good yield by oxychlorination of the main amount and after-chlorination of the residual amount of ethylene to give 1,2-dichloroethane of good quality. On the other hand, by using only one reaction unit, the new process enables the total amount of 1,2-dichloroethane to be obtained in good quality and yield for further thermal decomposition

237627 3

- 17 -

to provide for the production of vinyl chloride, with substantially complete reuse of incurred in the thermal decomposition of hydrogen chloride. In the reaction unit, a considerable amount of heat at a temperature level, which allows a favorable re-use of this heat, for example as a medium-pressure steam. The method does not require complicated, expensive or fault-prone apparatus, it can be carried out in apparatuses that are easy to clean and maintain.

The division of the ethylene introduction into the reaction space allows a more uniform temperature control and thus improved control of the course of the reaction.

Exemplary embodiments »;

Examples 1 to 7

The following equipment is used: To carry out the conversion of ethylene to 1,2-dichloroethane is a vertical glass tube with 80 mm inner diameter, which is tapered at the bottom and top of each Gaseinström- or Gasausströmöffnung. This vertical reaction tube contains a glass frit immediately above the lower inlet opening, which extends over the entire inner cross section of the reaction tube. At a short distance above this first frit, a second frit is attached, whose surface is about half the cross section of the reaction tube and which is connected in its lower part with a glass tube which is guided laterally through the jacket of the reaction tube.

237627 3

- 18 -

For temperature control, the reaction tube contains a glass tube coil, whose connections are also guided laterally through the jacket of the reaction tube and which begins just above the second frit and in the reaction tube extends upward so that about 1/10 of the entire length of the reaction tube in the upper part remain free. Between the second frit and the upper end of the .Reaktionsrohres 4 nozzles are uniformly distributed over the jacket of the tube, extend through the temperature sensor into the interior of the reaction tube. At certain intervals above the frit 2, the jacket of the reaction tube contains three further nozzles, can be passed through the gas inlet tubes, which extend to the middle of the reaction tube, bent there vertically downwards and terminate in a perforated ball. If a gas inlet tube is passed through the nozzle (A), which is mounted at the greatest distance from the second frit, the distance between the perforated ball and the second frit 69% of the entire inner length of the reaction space in the reaction tube. The reaction space is measured from the surface of the first frit to the rejuvenation point in the uppermost part of the reaction tube. If a gas inlet tube is passed through the neck (C), which is closest to the second frit, the distance from the perforated ball of the gas inlet tube to the second frit 17% of the total length of the reaction space in the reaction tube. If a gas inlet tube is passed through the nozzle (B), which is located between the two last-described nozzle, the distance from the perforated ball of the gas inlet tube to the second frit 53% of the entire length of the reaction space in the reaction tube. The entire jacket of the reaction tube is provided with a heat insulating layer.

237627 3

- 19 -

Above the reaction tube, a glass ball is mounted for the purpose of separating catalyst particles entrained in the gas stream. This glass ball in turn is connected via a descending line with a water cooler, at the lower end of a condensate collection vessel is mounted with drain cock. The Kondensatsammeigefäß contains in its upper part a gas discharge pipe, which in turn opens into an ascending brine cooler. The condensed components of the gas flow into a second Kondensatsammeigefäß with drain cock. The non-condensable exhaust gases leaving the upper part of the brine cooler are passed through wash bottles for the removal of the hydrogen chloride contained therein. From the scrubbed exhaust gas, samples are taken for gas chromatographic analysis. The condensates, which collect in the two vessels below the cooler, are combined and also analyzed by gas chromatography.

The glass ball, in which the entrained catalyst particles are deposited, as well as the outgoing from her transition pipe to the radiator are provided with electric heating sleeves. These parts of the apparatus are heated during operation of the reactor so far that no condensation occurs here.

The volume of the reaction space in the reaction tube minus the internals contained therein (temperature control coil, second frit, gas inlet ball and temperature sensor) is 4700 cm ³ .

To carry out the first example, the reaction tube is filled with 2.8 dm ³ (bulk volume) of a catalyst consisting of an alumina carrier and containing 3.7 wt .-%, based on the catalyst, copper in the form of a salt and traces of iron. The catalyst has the following siebanysis:

237627 3

- 20 -

Particles <20 μ 25% by weight

Particles> 20 μ, but <70 μ 65 wt .-% of particles> 70 μ 10 wt .-%.

The intrinsic volume of the catalyst is determined by the water displacement method: 1 measuring cylinder with 2 dm ³ content is first filled with 1 dm ³ catalyst particles and to 1 dm ³ water of 20 ⁰ C added. The mixture is shaken a little and allowed to stand for some time until no gas bubbles rise. The volume of the mixture is now 1300 cm ³ . 1 dm ³ (bulk volume) of the catalyst thus has a volume of the catalyst particles of 300 cm ³ . The total catalyst charge of 2.8 dm ³ has an intrinsic volume of 840 cm ³ .

The free gas space in the reaction tube after filling the catalyst is still 3.86 dm ³ .

Now, via the lower gas inlet tube through the first frit air in an amount of 60 normal dm ^3rd

blown per hour and the tempering coil in the

Reaction tube heated with a heating fluid. After about 25 minutes, an air temperature of 185 ⁰ C is measured in the reaction tube, which does not change within the next 5 minutes. Now the

blown in air quantity increased to 90 Ndm ³ · h and: at the same time over the second frit a mixture of

Ethylene in the amount given below and _ -ι

Introduced 44 Ndm ³ · h hydrogen chloride gas. Immediately afterwards, also with the introduction of

22 Ndm ³ · h of chlorine gas is introduced via the ball-headed gas inlet pipe mounted in the nozzle (A) farthest from the second frit, at the same time ethylene is injected in the amount indicated below through the ball-shaped gas inlet pipe, the is mounted in the middle port (B), fed into the reaction tube

237627 3

- 21 -

Nozzle, which is closest to the second frit, is not used, it is closed with a stopper). All supplied to the reaction tube gases are preheated to 60 ⁰ C.

The individual examples are total in each case

"1 44.5 Ndm ³ · h ethylene in the following subsets through the two points of introduction (second frit and port B) fed to the reaction tube:

In the case of ethylene via: play second nozzle No. frit B Ndi ^ h "" ¹ NdIn ³ li " ¹

% of total ethylene amount first subset second subset (remainder)

over about

second frit nozzle B

1 43.4 1.1 97.5 2 38.9 5.6 87.4 3 33.4 11.1 75.0 4 27.8 16.7 62.5 5 24.5 20.0 55.0 6 22.3 22.2 50.1 7 20.0 24.5 45.0

2.5 12.6 25.0 37.5 45.0 49.9 55.0

Together with the introduction of the reaction gases, the water cooler is charged with water of +14 ⁰ C and the brine cooler with cooling brine of -15 ⁰ C. The waste gas washing bottles contain water as washing liquid.

After a short time the temperature in the reaction tube has risen to 223 ⁰ C. It is maintained in the further course of the experiment by charging the temperature control coil with coolant at this temperature. The exhaust gas leaving the brine cooler has a temperature of +10 ⁰ C.

237627 3

- 22 -

The experiment is continued for 3 hours and after 1/3 and 2/3 of this time each once the exhaust gas composition of the scrubbed exhaust gas is determined by gas chromatography. For the gases oxygen, carbon monoxide, carbon dioxide and ethylene a thermal conductivity detector is used, for all other gases indicated below a flame ionization detector. The mean values from both analyzes are summarized for Examples 1 to 7 in Table II below, wherein the oxygen value of the noble gas component brought along via the air used has already been calculated.

After the end of the experiment, the gas supply to the reaction tube is stopped and the catalyst is cold-blown with air (about room temperature). The condensate formed by the water and brine cooler is combined, weighed and also analyzed by gas chromatography with a flame ionization detector. The values determined for Examples 1 to 7 are listed in Table I below. *

The following values are found for examples 1 to 7: Molar ratio HCL: C ₂ H ₄ : Cl ₂ : O ₂ = 2: 2.05: 1: 0.86

Average residence time of the gases in the reaction space: 40 s. Space-time yield in g of crude 1,2-dichloroethane · h · based on 3.86 dm ³ reaction space.

30 example no. , .1 2 3 4 5 6 7 Space-time Aubeute 48.7 48.4 48.3 48.0 47.8 47.6 47.4

TABLE

Gas chromatographic analysis of the condensed Example No. 1% by weight Example No. 2% by weight Crude 1,2-dichloroethane Example No. 4% by weight Example No. 5% by weight Example No. 6% by weight Example No. 7% by weight N> ^! W Compon. ducks 98.211 98.122 Example no. 3% by weight 97.835 97.748 97.592 97.394 7 62 I 0.001 0.001 0.001 0.001 0.001 0,002 1,2-dichloroethane 0.001 0,002 98.026 0.001 0,002 0.001 0.001 Sum of C ₂ H ₂ ; C ₂ H ₄ ; C ₂ Hey 0,025 0.024 0.001 0,030 0.024 0,025 0.028 OJ vinyl chloride 0,012 0.013. 0.001 0,013 0,014 0,012 0.01 3 C ₂ H ₅ Cl 0,008 0.009 0,030 0,008 0.009 0,008 0.009 1,2-dichloroethylene (trans 0.047 0,030 0,015 0.032 0.047 0,029 0,035 1,1-dichloroethane 0,075 0.078 0,008 0.083 0.084 0.085 0,089 CCl ₄ 0,020 0,022 0,042 0,025 0,022 0.023 0.024 1,2-dichloroethylene (ice) 0,004 0.005 0.074 0,007 0,006 0,007 0,006 CHCl ₃ 0,951 1,042 0.023 1.298 1,293 1,448 1,612 1,1,2-trichlorethylene 0.005 0,006- 0,004 0,003 0,006 0.005 0,003 1,1,2-trichloroethane 0.412 0.408 1,105 0.434 0.485 0.499 0.512 2-chloroethanol 0.225 0.234 0,004 0.225 0,255 0,258 0.265 1,1,2,2-tetrachloroethane 0.422 chloral 0.240

, T A B E L L E II Gas chromatographic analysis of the exhaust gas after the hydrogen chloride scrubbing

Components Example Example Example Example Example Example Example / «%

No.1 No 2 No 3 No 4 No 5 No 6 No 7

O ₂ 5.30 5.35 5.45 5.65 5.85 6.10 CD 6.30 CO 1.65 1.70 1, 70 1.65 1.60 , 1/60 1.58 CO ₂ 1, 95 1.95 2.00 1.95 1.90 1.85 1,80 ^ C ₂ H ₄ 0.95 1.00 0.98 1.05 1.10 1.25 1.50 vinyl chloride 0.001 0,002 0.001 0.001 0.001 0.001 0.002 ^KAJ C ₂ H ₅ Cl 0.011 0,012 0,012 0,013 0,014 0,015 0.016 _N low boilers 0,010 0,008 0.009 0.011 0,010 0,012 0.013 * "• 1,2-dichloroethane 2.20 2.35 2.40 2.25 2.45 2.20 2.30 high boiler 0.001 0.001 0.001 0.001 0.001 0.001 0,002 1,1,2-trichloroethane 0.009 0,008 0.009 0,012 0,013 0,013 0,015 Cl2 in the exhaust free free free free free free free CI2 in the water free free free free free free free Cl ₂ in crude 1,2-dichloroethane free free free free free free free Sales, based on: (in%) HCl 97 96 96 95 93 91 90 C ₂ H ₄ 96 96 95 94 94 93 93 Cl ₂ 1 00 100 100 100 100 100 100

237627 3

-25 -

Examples 8 to 11

The same apparatus and type and quantity of the same catalyst is used as in Examples 1 to 7, but with the difference that a gas inlet tube with a spherical end in the neck (C) is arranged on the reaction tube, the next the second frit, so that, as already mentioned above, the ball of the gas inlet tube from the second frit is at a distance of 17% of the total length of the reaction space. The spigot located farthest from the second frit and the spigot located at 53% of the height of the reaction space away from the second frit are not used. They are closed with plugs. Through the lower opening of the reaction tube, a mixture of 90 Ndm ³ · h air and 22 Ndm ³ · h chlorine is introduced, which enters via the first frit into the reaction space. About the second frit, a portion of the ethylene and the tube with the spherical end 44 Ndm ³ · h ~ hydrogen chloride gas and the remainder of the ethylene is introduced. In. In the individual examples, a total of 45 Ndm ³ · h of ethylene in the following subsets through the two introduction points (second frit and port C) are fed to the reaction tube:

At game no. Ethylene second frit Ndm ³ h ~ ¹ via nozzle NdTn ³ IT ¹ % of the total amount of ethylene first subset second subset of (remainder) on second frit nozzle c 2.4 8th 43.9 1.1 97.6 25.1 9 33.7 11.3 74.9 50.0 10 22.5 22.5 50.0 54.9 11 20.3 24.7 45.1

The temperature in the reaction chamber is kept constant at 222 ⁰ C, the test duration is 3 hours. Otherwise, the further procedure is as described in Example 1.

237627 3

- 26 -

For examples 8 to 11 the following values are found:

Molar ratio: C ₂ H ₄ : HCl: Cl ₂ : O ₂ = 2: 1.95: 0.98: 0.84

 Average residence time of the gases in the reaction space: 40 s.

Space-time yield in g of crude 1,2-dichloroethane · h · dm ~ 3, based on 3.86 dm ^{3 of} reaction space:

Example no. 8 9 10 1.1

Space-time yield 48.7 48.5 48.4 48.6

For crude 1,2-dichloroethane and exhaust gas analyzes, see Tables III and IV below

 15

In all the examples described (Nos. 1 to 11) is carried out at normal atmospheric pressure of 97.3 kPa.

237627 3

- 27 -

TABLE III

Gas chromatographic analysis of the fused crude 1,2-dichloroethane

components

Example Example Example Example No. 8 No. 9 No. 10 No. 11

Weight% weight% weight% weight%

1,2-dichloroethane 98.327 98.264 98.258 98.207 Sum C2H2; C2H4; C2H6 0,002 0.001 0.001 0,002 vinyl chloride 0,003 0,003 0,002 0,003 C ₂ H ₅ Cl 0.011 0,020 0,020 0,022 1,2-dichloroethylene (trans.) 0,018 0,020 0,018 0,017 1,1-dichloroethane 0.009 0.009 0.009 0,010 CCl ₄ 0.082 0,089 0.094 0.088 1,2-dichloroethylene (ice) 0.084 0.088 0,095 0,099 CHCl ₃ 0.054 0,055 0.056 0.063 1,1,2-trichlorethylene 0.005 0.005 0,006 0,006 1,1,2-trichloroethane 0.709 0.729 0.749 0.766 2-chloroethanol 0,003 0,003 0,003 0,003 1,1,2,2-tetrachloroethane 0.340 0.355 0.351 0,369 ' chloral 0,350 0.354 0.335 0.340

237627 3

 - 28 -

TABLE IV

Gas chromatographic analysis of the exhaust gas after the hydrogen chloride scrubbing

components

Example Example Example Example No. 8 No. 9 No. 10 No. 11

O ₂ 1.50 1.50 1.40 1.50 CO 2.50 2.60 2.60 2.55 CO ₂ 3.20 3.30 3.35 3.30 C ₂ H ₄ 0.54 0.48 0.44 0.48 vinyl chloride 0,002 0,002 0.001 0,002 C ₂ H ₅ Cl 0,012 0,013 0,014 0.011 low boilers * 0.008 0,007 0.009 0,008 1,2-dichloroethane 2.40 2.35 2.45 2.40 high boiler <0.001 <0.001 <0.001 <0.001 1,1,2-trichloroethane 0,004 0,003 0.005 0,004 Cl ₂ in the exhaust free free free free Cl ₂ in the water free free free free Cl ₂ in crude 1,2-dichloroethane free free free free Sales, based on (in%): HCl 97 97 97 97 C ₂ H ₄ 95 95 95 95 Cl ₂ 100 100 100 100

237627 3

- 29 -

Examples 12 and 13

The apparatus used for this purpose is constructed analogously to that used in Examples 1 to 7, but with the difference that a vertical nickel tube with 50 mm inner diameter is used as the reaction space, which is equipped similar to the glass tube of the apparatus used for Examples 1 to 7 , with the following differences: There are only three temperature measuring points uniformly distributed over the jacket of the reaction tube. Viewed from bottom to top, the first two frits are mounted as described in the apparatus for Examples 1-7. Then a third frit follows and above that a fourth. The distance from the second frit amounts to 41% for the third frit and 47% of the entire inner length of the reaction space for the fourth frit. Also at the head of the tube, immediately before the taper, a fifth frit is installed, which is used to reduce pressure and to retain entrained catalyst particles, which is omitted in the glass apparatus provided for this purpose sphere. At the reactor outlet a pressure reducing valve is attached. The spherical head gas introduction tube is fixedly incorporated into the reactor, the distance from the ball to the second frit (from below) being 56% of the length of the entire reaction space measured between the lowest and the highest frit in the tube. In the upper part of the tube, a pressure measuring device is mounted.

The content of the reaction space minus the volume of the internals therein (temperature control coil, gas inlet tubes with frit or ball head, temperature sensor) is 1500 cm ³ . At the reactor outlet downstream of the pressure reducing valve, water and brine coolers and hydrogen chloride scrubbers are connected, as described in Examples 1 to 7.

237627 3

- 30 -

The nickel tube is filled with 1 dm ³ (bulk volume) of a catalyst containing copper chloride on alumina and a copper content of 4.5 wt .-%, based on the catalyst having. The catalyst contains no iron and has the following sieve analysis:

Particles <20 μ 22% by weight

Particles> 20 μ but <70 μ 67% by weight Particles> 70 μ 11% by weight

The self-volume of the catalyst is determined as described above, according to the water displacement method to 310 cm ³ . The free space available for the gas reaction is 1190 cm ³ .

60 Ndm ³ .h of air are first blown through the first (lowest) frit under pressure through the lowest Gaszuführungsleitung and heated the reactor by means of the temperature control coil to 240 ⁰ C. By regulating the pressure reducing valve at the top of the reactor, a pressure of 500 kPa is set in the reactor. After half an hour, temperature and pressure constancy in the reaction tube is reached. Now, the blown air quantity is increased to 90 Ndm ³ · h and injected by the second, third and fourth frit following gas amounts:

Ex. over 2. frit about 3rd frit over 4. frit % of the total second part No. nc In ³ h " ¹ Ndm ³ IT ^ C ₂ Hi Ndm ³ b -'Cl ₂ amount of ethylene amount over C ₂ Hn + HCl first part 3. frit amount over 2. frit 25.5 12 26 50 25 25 51 13 38 50 13 25

The temperature in the reaction chamber increases and is adjusted by introducing a cooling medium in the temperature control coil in Example 12 at 280 ⁰ C, in Example 13 to 265 ⁰ C and kept constant for a further 3 hours.

237 62 7 3

- 31 -

Introduced into the reaction chamber gases are preheated to 60 ⁰ C. When the 3 hours have elapsed, the gas supply is interrupted and the catalyst in the reaction tube is cold-blown with air (approximately room temperature). . ' , ·.,

During the entire test duration, the water cooler with water of + 12 ⁰ C and the brine cooler is traversed with cooling brine of -20 ⁰ C. The exhaust gas leaving the brine cooler has a temperature of +11 ⁰ C.

During and after the respective experiment, the sampling and sample evaluation are carried out as described in Examples 1 to 7. The values determined are listed in Tables V and VI below:

For examples 12 and 13 the following values are found:

Molar ratio: HCl: C ₂ H ₄ (total): Cl ₂ : O ₂ =

'2: 2.04: 1: 0.75

Average residence time of the gases in the reaction space:

Example 12: 55 s; Example 13: 58 s.

"Space-time yield in g of crude 1,2-dichloroethane:

«H ~ ¹ · dm" ³ , based on 1.19 dm ³ reaction space.

Example 12: 181; Example 13: 182.

237627 3

- 32 -

TABLE V

Gas chromatographic analysis of the fused crude 1,2-dichloroethane

example example components No. 12 JVR. 13 Weight % Wt .-% 1,2-dichloroethane 9 7,083 97.779 Sum C ₃ H ₂ ; C ₃ H \; C ₂ Hs O, 001 0.001 vinyl chloride 0.028 0,022 C ₃ H ₅ Cl 0,068 0.064 1,2-Dichiore thy1 en (trans) 0.016 0.011 1,1-dichloroethane 0,006 0,006 CCl _t 0.048 0.054 1,2-dichloroethylene (ice) 0,042 0,038 CHCl ₃ 0,015 0,017 1,1,2-trichlorethylene 0,003 0.005 1,1,2-trichloroethane 1,567 1,012 2-chloroethanol 0,038 0,042 1,1,2,2-tetrachloroethane 0,756 0.643 chloral 0,310 0,290

237627 3

- 33 -

TABLE VI

Gas chromatographic analysis of the exhaust gas after the hydrogen chloride scrubbing

components 'Example No. 12 VoI .-% example No. 13 VoI .-% O ₃ 1.0 2.4 CO 2.7 2.1 CO ₃ 3.1 2.8 C ₂ H _A 0.12 0.18 vinyl chloride 0,040 0,025 C ₃ H ₅ Cl 0.056 0.048 low boilers 0,035 0,036 1,2-dichloroethane 2.65 2.25 high boiler 0.01 0.005 1,1,2-trichloroethane 0.005 0,004 Cl ₃ in the exhaust free free Cl ₂ in the water free free Cl ₂ in crude 1,2-dichloroethane free free Turnover based on (in%): HCl 99 99 Cl ₃ 100 100 CH 95.3 96.4

Claims (1)

2 3 7 6 2 7 3 ³⁴ ~ ^{H0E 81 / F} invention claim Process for the preparation of 1,2-dichloroethane from ethylene by reaction with hydrogen chloride and oxygen-containing inert gases at 180 to 300 ° C and 0.1 to 1/1 MPa.sowie by reaction with chlorine in the gas phase in the presence of a copper or copper - Andeisensalzhaltigen solid catalyst with subsequent cooling and distillative separation of the reaction mixture, wherein both chlorination reactions in a common reaction chamber containing fluidized catalyst particles are carried out sequentially, and the heat formed in the entire reaction space is removed by indirect cooling with a liquid and / or gaseous heat transfer medium , characterized in that 98 to 40% of the total amount of ethylene introduced into the common reaction space is introduced into the zone of the reaction space in which the first chlorination reaction takes place, and the remaining 2 to 60% of the total amount in the common reaction space. introduced ethylene volume is introduced into the zone of the reaction space in which the second chlorination reaction takes place.