NO820572L - PROCEDURE FOR THE PREPARATION OF 1,2-DICHLORETHANE - Google Patents

Description

The invention relates to a method for the production of 1,2-dichloroethane, whereby ethylene is reacted with hydrogen chloride, oxygen-containing inert gas and chlorine in a common reaction space in the presence of a catalyst.

1,2-dichloroethane has already been produced for a number of years

largely industrial. It is mainly converted by thermal decomposition into vinyl chloride, which in turn is the basis for the pulp plastic polyvinyl chloride. This application has made 1,2-dichloroethane one of the most produced aliphatic chlorinated hydrocarbons. A number of different methods are known for its production, most of which start from ethylene. Usually elemental chlorine is added directly to ethylene, as

you work with temperatures from 4-0 to approx. 120°C in liquid phase, often in 1,2-dichloroethane. In a widely used form of this method, the considerable amount of heat produced by chlorine deposition is removed by means of boiling 1,2-dichloroethane.

As the boiling point for 1,2-dichloroethane at normal atmospheric pressure is approx. 84.°C, the temperature level at which the amount of heat is carried away either does not reach to produce water vapour, or water vapor can only be obtained at lower temperatures and thereby lower pressure levels, so that it is only of limited use for re-use. the energy contained therein.

For better utilization of the heat of reaction of the direct chlorine deposit. to ethylene it is known to carry out

.the conversion in the gas phase in the presence of a stirred catalyst,

and immediately thereafter cleaving the 1,2-dichloroethane formed to vinyl chloride. The catalyst particles thereby act as heat exchangers, working at temperatures of 370 to 540°C and pressures of up to 2.2 MPa, preferably at 0.45 to 1.85 MPa. The chlorinated hydrogen produced by the splitting of fti, 2-dichloroethane is used in a separate apparatus for the oxychlorination of ethylene. The 1,2-dichloroethane produced from this is returned to the fluidized bed reactor.

Disadvantages of the process such as formation of considerable amounts of ethylene chloride, relatively large amounts of non-converted 1,2-dichloroethane in the cleavage products, difficulties in regulating and controlling the process, tendency to form unwanted polychlorinated hydrocarbons and to resin formation and wax formation of the split reactor must be reduced when instead of, for example, dehydrochlorination catalysts. fluidized non-catalytic solids are used in the reactor. Furthermore, the chlorine must be introduced into the chlorination reaction zone, controlled in a number of different places to reduce the risk of coking. For this, a particularly relatively cumbersome installation in the fluidized-bed-slit reactor is necessary.

There is also the difficulty of separating the hot fission gases as completely as possible from the swirling fine particles,

solid heat transfer medium, and the disadvantage that with this method, the industrially preferred tube-slitting furnace cannot be used on liquid gaseous 1,2-dichloroethane, which enables high production rates.

A method for the production of 1,2-dichloroethane is also known, in which in a first step excess ethylene chlorohydrogen and excess oxygen in the form of air are reacted in the presence of a known oxychlorination catalyst by corresponding setting of the quantity ratio and the starting materials under more than 90% conversion of hydrogen chloride at 180 to 350°C, and the residual gases from this step after washing out of unreacted hydrogen chloride and the resulting condensation of a large part of the 1,2-dichloroethane formed are converted into a second step with 80 to 120 mol% chlorine, referred to the ethylene used in this step in the presence of a ferrous catalyst at 80 to 250°C.

The corresponding method works as well

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

In recent times, it has been known to reduce the considerable amounts of 2-chloroethanol formed by the subsequent chlorination of excess ethylene from the oxychlorination by carrying out the reaction in the presence of added hydrogen chloride.

Finally, a method is known to reduce the by-products from the chlorination of ethylene-containing gases which appear after the oxychlorination and separation of the main amount of organic products formed by rapid cooling with water, by carrying out the chlorination in the presence of copper (II) chloride and/or j ern (111)-claw ride on. a carrier as a catalyst.

All of these latter methods have the disadvantage that an additional reactor with a product separator and additional devices are required to improve the yield of 1,2-dichloroethane, referred to the methylene used in the oxychlorination. A method has now been found by which the oskychlorination can be carried out as well as the direct chlorine addition to ethylene in a common reaction room with good yields, to 1,2-dichloroethane at a reaction temperature level that enables a significantly better utilization of the heat of reaction carried away by the chlorine addition to ethylene , than according to the hitherto widely used method with chlorination in boiling '1,2-dichloroethane-.

The invention relates to a process for the production 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 and by reaction with chlorine in the gas phase in the presence of a copper or copper and iron salt-containing solid catalyst with subsequent cooling and distillative separation of the reaction mixture in which both chlorination reactions are carried out one after the other in a common reaction space that contains stirred. catalyst particles, and the heat generated in the overall reaction space is removed by indirect cooling with a liquid and/or gaseous heat transfer medium, the method being characterized by 98 to 4-0% of the total quantity of the introduced into the common reaction space

ethylene plume is introduced into the zone of the reaction chamber in which

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

Two chlorination reactions can be carried out one after the other in any order, as a qualitatively high quality •'', 2-dichloroethane is obtained in good yields even when the amount of ethylene converted in each chlorination reaction is approximately the same. The latter method is a preferred variant of the method according to the invention when the produced 1,2-dichloroethane is then converted as usual with thermal cleavage to vinyl chloride, as in this way the total amount of the 1,2-dichloroethane to be split can be produced in a reaction unit under good heat utilization see that the hydrogen chloride produced by the splitting process is supplied to the 1,2-dichloroethane production and used for chlorination of approximately half

■of the total ethylene used.

As a heat transfer medium for its removal

heat generated in the overall reaction space by indirect cooling, for example high-boiling mineral oil and silicone oil are suitable. Preferably, water is used which is converted by heat absorption into medium pressure steam. 1 a preferred embodiment of the method according to the invention is introduced into the reaction space first the oxygen-containing inert gas, a first partial amount of ethylene and hydrogen chloride and then the second partial amount of ethylene and chlorine 1 the following molar ratio: 2 mol HC1, 1.01 to 3 mol C2H^ (total amount), at least 0.5, usually 0.5 to 1 mol O2 and 0.009 to 2 mol CI2, where the amount of chlorine is diluted so that less than 0.001 wt% free elemental chlorine.

The total quantity specified in the preceding paragraph

of ethylene of 1.01 to 3 mol is divided so that at 98 to

40% of this total amount, preferably 95 to 60% of this total amount, is introduced together with hydrogen chloride or in its immediate vicinity into the reaction space. The remaining 2 to 60%, preferably 5 to 40% of the total amount of the ethylene, is introduced into the reaction space in the vicinity suitably shortly before the place where chlorine is introduced into the reaction space. When, for example, the total amount of ethylene filled into the reaction space during a certain time amounts to 2 mol, then 98 to 4-0% of this is introduced, that is 1.96 to 0.8 mol, preferably 95 to 60% , it is 1.9 to 1.2 moles of ethylene together with hydrogen chloride, and 2 to 60%, it is 0.04 to 1.2 moles, preferably 5 to 40%, it is 0.1 to 0.8 moles of ethylene , is introduced shortly before the introduction of chlorine into the reaction chamber. When less than 40% of the total amount of ethylene is introduced together with hydrogen chloride or in its immediate vicinity, a decrease in the yield of 1,2-dichloroethane is observed, and an increase in the amount of unwanted by-products.

By inert gas is meant such substances as

is gaseous under the reaction conditions, and overhead does not, or only to a lesser extent, participates in the reaction. Examples of inert gas are nitrogen, carbon dioxide and 1,2-dichloroethaneT.vapour. Nitrogen is preferably used as an inert gas. The amount of inert gas is appropriately dimensioned so that sufficient stirring of the solid catalyst particles is achieved without diluting the reaction mixture too much.

Oxygen is preferably introduced to at least 50 to

100%, especially to 90 to 100% of the total amount of air entering the reaction space.

All gases are preferably brought into the reaction chamber with low relative humidity. The chlorine hydrogen gas preferably originates from the thermal decomposition of 1,2-dichloroethane to produce vinyl chloride. Before being introduced into the reaction space, the gases can, for example, be preheated to temperatures of 60 to 180°C.

All gases can be introduced individually ethylene in at least

2 partial amounts into the reaction space, preferably introduced

however, hydrogen chloride and a first portion of the ethylene on one side, as well as oxygen and inert gas, for example as air on the other hand, each time in a mixture with each other. In the case of discontinuous operation, the chlorine can be introduced temporally in the case of the preferred continuous operation spatially after the introduction of the other gases into the reaction space. Preferably, shortly before the introduction of chlorine, another sub-quantity of the ethylene is fed into the reaction sro etc.

The reaction space can, for example, have a spherical ellipsoidal or cylindrical shape, it should be designed so that it has no dead corners and angles, in which the stirred-up catalyst can settle. Preferably, an elongated cylindrical reaction chamber with a circular cross-section is used and. vertical cylinder axis, for example a pipe.

The reaction chamber is appropriately equipped with a double jacket, as well as built-ins through which the heat transfer medium flows. Suitable installations are, for example, hose or tube register coolers. These built-ins can

be arranged in several units separated from each other, which can be flowed through by different media at different flow rates in order to enable an optimal heat utilization of an optimal temperature course in the reaction space.

The different gases can be passed through simple pipes. into the reaction space, and as appropriate at their end contains devices for better distribution over the surface. Such suitable devices are, for example, perforated plates or balls, frits or a resp. several pipes with a majority of gas outflow soaps.

The reaction chamber appropriately contains in its uppermost zone an opening with an adjustable cross-section, through which the reaction product is carried away. After leaving the reaction space, the reaction products conveniently pass a separator for finely divided, solid catalyst particles, for example a cyclone or similar device. The separated particles are fed back into the reactor.

After leaving the separators, the gases are washed and possibly partially condensed, at normal pressure at approx.

10°C non-condensable gas parts are discharged into the atmosphere, possibly after separation of harmful or disturbing substances. At least part of the non-condensable gases can also be returned to the reaction space by circulation. The condensed reaction products are separated by distillation as usual to extract pure 1,2-dichloroethane.

In a particularly preferred embodiment of the invention, the substances to be reacted are introduced into the reaction space in the following quantity ratio: 2 mol F Hl, 1.8 to 2.2 mol (total amount), 0.5 to 0.6 mol O^ and 0.79 to 1.2 mol Cl^, the amount of chlorine being sized so that less than 0.001% by weight of free elemental chlorine is found in the gas mixture leaving the reaction space. By using this molar ratio, 1,2-dichloroethane for the subsequent cleavage into 1-vinyl chloride can be produced with optimal utilization of the hydrogen chloride returned from the cleavage process, as well as the inputs ethylene and chlorine in a single reaction unit.

As mentioned above, the total amount of the ethylene of 1.8 to 2.2 mol is divided so that 98 to 4-0% of the total amount, preferably 95 to 60% of this total amount is introduced together with the hydrogen chloride or in its immediate

only proximity into the reaction space. The remaining 2 to 60%, preferably 5 to 4-0% of the total amount of ethylene, is pasted into the reaction space nearby, conveniently shortly before the place where chlorine is introduced into the reaction space. The methods mentioned in the two previous paragraphs are carried out in particular so that at one end of the tubular reactor, suitably at the lower end of a vertical or approximately vertically standing tubular reactor, a first sub-quantity of ethylene, hydrogen chloride and oxygen-containing inert gas is introduced separately or at least partially separated apart. It may

for example, the first partial amount of ethylene and chlorine hydrogen is introduced together, however, separated from the oxygen-containing inert gas. At a certain distance, removed from the gas-to-the-sentence last of the above-mentioned gas inlets, chlorine is introduced, and suitably shortly before another sub-quantity of ethylene into the reaction space. The position of the chlorine introduction is chosen so that between it and the preceding chlorine hydrogen introduction there is a reaction ion space which amounts to 4-0. to 85%, preferably 55 to 75% of the overall available reaction space in the reactor. At the other end of the reactor, conveniently at the upper end of the vertical or approximately vertically standing tubular reactor, the reaction product is removed.

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

According to a further preferred embodiment of the method according to the invention, inert gas is first introduced into the reaction room. which may optionally contain oxygen, as well as a first portion of ethylene, and separated from it chlorine, and then chlorine hydrogen, another portion of ethylene and possibly oxygen and inert gas according to the final molar ratio: 2 mol C0H, (total amount), 0, 9 to 1.2 mol Cl„, 1.6 to 2.3 mol HC1, and 0.35 to 1.3 mol in total as oxygen or the amount of chlorine hydrogen is dimensioned so that in the end product, i.e. in the gas mixture that leaves the reaction room, there is less than 0.001 weight? free, elemental chlorine.

The total of 2 moles of ethylene used during a certain time are divided so that 98 to 4-0% of this total amount is introduced in the immediate vicinity of the chlorine introduction 1

into the reaction space. The remaining 2 to 60% of the total amount of ethylene is fed either the same with hydrogen chloride, or in its vicinity or just nearby into the reaction space.

This embodiment of the method is used in particular when, for example, to prevent the part of 2-chloroethanol in the reaction products, a small excess of hydrogen chloride must be used. As already discussed above is .

this embodiment is also suitable for producing 1,2-di-ichloroethane from the thermal cleavage to vinyl chloride, with optimal utilization of the hydrogen chloride produced by this cleavage, as the overall 1,2-dichloroethane production takes place in a single reaction room.

As inert gas, as mentioned above, for example nitrogen, carbon dioxide and/or 1,2-dichloroethane vapour, nitrogen being preferably used. The main amount of the required oxygen is suitably supplied at the point where the hydrogen chloride is also introduced, however, the supply of considerable amounts of oxygen is also possible, already at the point where the first sub-quantity of ethylene and chlorine is introduced. This method is used in particular when air is to be used as the inexpensive swirl gas.

The procedure mentioned in the four previous sections is carried out in particular so that at one end of a tubular reactor, suitably at the lower end of a vertical or approximately vertical tubular reactor, a first partial quantity of ethylene, chlorine and inert gas is introduced , as

optionally, may contain oxygen, at least partially separated from each other. Inert gases can, for example, also be introduced in a mixture with chlorine, however the first part of the ethylene is separated from this. At a certain distance removed from the last above-mentioned gas inlets in the direction of gas flow,; hydrogen chloride and possibly oxygen and inert gas are introduced separately or, at least partially separated, into the reaction space.

The position of the chlorine hydrogen introduction is chosen so that between it and the preceding chlorine introduction, there is a reaction space which makes up 10 to 40%, preferably 15 to 30% of the total available reaction space in the reactor. Another sub-quantity of ethylene is introduced together with hydrogen chloride or in its immediate vicinity into the reaction space. At the other end of the reactor, expediently, at the upper end of a vertical or approximately vertical tubular reactor, the reaction product is removed.

In the just-mentioned embodiment of the new method, the heat transfer medium in the indirect cooling of the reaction space is fed, preferably in direct current, to the gases.

The method according to the invention is preferably carried out at temperatures of the reaction mixture in the reaction space of 190 to 250°C, particularly at 200 to 230°C. In this way, a spatial temperature gradient can be used, especially in the case of a continuous process. For example, a lower temperature may prevail at the point of introduction of the gases into the reaction space than at the point of withdrawal of the reaction products. The temperature can too. viewed in the direction of flow of the gases, be higher in the first third of the reaction space, or in the middle or in the second third, than in the remaining areas of the reaction space.

The gases are preferably heated before introduction into the reaction chamber to temperatures of 50 to approximately 180°C. The new procedure can be carried out by normal atmospheric pressure, of about 0.09 to 0.1 MPa. Usually, an increase in rotation time is used instead of an increased pressure up to approx. 1.1 MPa. Work is preferably done at a pressure of 0.3 to 0.6 MPa.

The solid catalyst is preferably used in finely divided form, with an average particle size of 20 to 4-00 µm. In particular, good results are obtained with a catalyst with an average particle size of 30 to 70 µm.

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

On. this carrier material has been appropriately erected approx. 0.5 to 15 weight? referred to the overall catalyst of copper, as salt or oxide. These copper salts or oxides usually transform during use due to the hydrogen chloride present and. chlorine .to copper (II) chloride if they were not already applied as this chloride from the beginning.

Next to copper, the catalyst can advantageously ■ also contain smaller amounts of Lewis acids, especially approx. 0.01 to 0.5 wt?, referred to the overall catalyst, iron, which was applied as oxide or as salt, and during the reaction is converted into Lewis acid iron(III) chloride. The above-mentioned percentages each time refer to metal ions, not to the chloride or metal salt or oxide.

In addition to the new additions, the catalyst can also contain further additions, which reduce the volatility, especially of copper (II) chloride, for example alkali metal chlorides, such as potassium chloride or alkaline earth metal chlorides, such as calcium or magnesium chloride, as well as additions of further metallic compounds which improves the effectiveness and/or selectivity of the catalyst. with regard to the production of 1,2-dichloroethane. Examples include silver, zinc, chromium, manganese, rare earth metals such as cerium, lanthanum, ytterbium and neodymium, platinum metals such as rhodium, platinum.

Mixtures of different catalyst and catalyst support particles can also be used, for example support material treated with copper salt mixed with particles of untreated or another, for example support material treated with iron (III) chloride or another Lewis acid.

The ratio of the total reaction space before filling in the catalyst and the filled. the catalyst's volume, suitably amounts to approx. 1.1 to 3, preferably 1.2 to 1.7.

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 stirred up. Correspondingly, j is the feed of any inert gas introduced into the circuit and choose taking into account the gases fed into the reaction space and participating in the reaction.

The average residence time of the gases participating in the reaction in the reaction space depends on the chosen reaction temperature, as usually the residence time should be the shorter the higher the reaction temperature is set. The average residence time is usually 10 to 100, preferably 20 to 70 s, and especially 3'0 to 60 s. It is determined by continuous operation of the volume of gases fed into the reaction space during 1 second, at a pressure and temperature - '; flow that prevails in the reaction space with regard to the volume of the overall reaction space minus the intrinsic volume of the "catalyst" contained therein and the built-ins (cooling tubes, temperature measuring tubes). The intrinsic volume of the catalyst particles is determined, for example, according to the liquid displacement method (see below).

Preferably, it is introduced into the reaction space during the process. According to the invention, as much oxygen resp.

oxygen-containing inert gas in the gas mixture which leaves the reaction space after condensation and the easily condensable reaction products (e.g. water and 1,2-dichloroethane) at +10°C and. separation of the hydrogen chloride by ordinary washing, moreover, is. contained 2 to 9, especially L to 7 volume? oxygen. The. is, for example, with regard to washing the exhaust gases with organic flammable solvents to remove residual amounts of 1,2-dichloroethane advantageous when the 02 content of the above-mentioned pre-treated exhaust gas is not too high, for example below 9 volume?. If no such post-purification is prescribed, the oxygen content can also be

also lie higher,' for example at 10 to 13 volume?, as very good yields of 1,2-dichloroethane are still obtainable.

1

Separation and purification of the gas mixture that leaves the reaction chamber takes place as mentioned above according to known methods.

As also indicated above, the process according to the invention enables, on the one hand, in a single reaction unit to convert ethylene with particularly good yields by oxychlorination of the main amount, and post-chlorination of the residual amount of ethyl en. to 1,2-dichloroethane of good quality. On. on the other hand, the new process, using only one reaction unit, provides the total amount of 1,2-dichloroethane in good quality and yield, for the further thermal cleavage for the production of vinyl chloride with the most complete possible recycling of the hydrogen chloride formed by the thermal cleavage . A considerable amount of heat is generated in the reaction unit. a temperature level that enables a favorable further use of this heat, for example. as medium pressure heating. The method does not require any complicated expensive or disruptive apparatus which are easy to clean and maintain.

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

The invention shall be explained in more detail by means of. some examples.

Example■ 1 to 7

The following apparatus is used: To carry out the conversion of ethylene to 1,2-dichloroethane, a vertical glass tube with an internal diameter of 80 mrn is used, which is tapered at the bottom and top to form a gas inlet on each side. respectively gas outflow opening. This vertical reaction tube contains immediately above the lower inflow opening a glass frit which extends over the entire internal cross-section of the reaction tube. At a short distance above this first frit, another frit is placed whose surface makes up approximately half the cross-section of the reaction tube and which in its lower part is connected to a glass tube which in turn is guided. through the jacket of the reaction tube.

For tempering, the reaction tube contains a glass tube whose connection is also led laterally through the reaction tube's mantle and which begins shortly above the second frit and only reaches slightly upwards into the reaction chamber, approx. 1/10 of the total reaction tube length remains free in the upper part. Between the second frit and the upper end of the reaction tube, evenly spaced L stubs are placed over the tube's mantle, through which temperature measuring sensors reach into the interior of the reaction tube. At a certain distance above the frit, 2, the reaction tube's mantle 3 contains additional nozzles, through which the gas inlet tubes can be passed, which extend to the middle of the reaction tube, which is bent vertically downwards, and ends in a hollow sphere. If the gas introduction pipe is led through the spigot (A) which is placed at the greatest distance from the other frit, the distance between the hollow ball and the other frit constitutes 69% of the total internal length of the reaction space in the reaction tube. The reaction space is measured from the surface of the first frit to the point of taper in the upper part of the reaction tube. If a gas inlet pipe is routed through the socket (C) which is closest to another frit, the distance from the gas inlet pipe's perforated ball to another frit constitutes 17% of the total length of the reaction space in the reaction pipe. When a gas inlet pipe is passed through the spigot (B) which is located between the two last-mentioned spigots, the

the distance from the perforated ball of the gas inlet tube to another free 53% of the total length >of the reaction space

■in the reaction tube. The overall jacket of the reaction tube is equipped with a thermal insulation layer.

A glass ball is placed above the reactive ion tube for the separation of catalyst particles that are carried along by the gas stream. This glass sphere is again connected via a downward-going line to a water cooler, at the lower end of which is placed a condensate collection vessel with an outlet tap. The condenser sat collection air contains in its upper part a gas supply pipe which in turn opens into an ascending salt ice cooler. The components of the gas condensed here flow into another condensate collection vessel with an outlet tap. The condensable off-gases that leave the brine in the upper part of the boiler are passed through washing bottles for the separation of hydrogen chloride contained therein. Samples are taken from the washed exhaust gas for a gas chromatographic analysis. The condensates that collect in the two vessels placed below the cooler are combined and analyzed in the same way gas chromatographically.

The glass sphere, in which the entrained catalyst particles are separated, as well as the transfer pipe1" that goes out from it to the water cooler, are equipped with electric heating cuffs. These apparatus parts are heated under the weight of the reactor to such an extent that no condensate formation occurs here.

The volume of the reaction space in the reaction tube minus

.the built-ins contained therein (tempering hose, other frit, gas introduction ball, and temperature measuring sensor) out-3

make 4-70 0 em' .

For carrying out the first example, the reaction tube is filled with 2.8 dm 3 (shake volume) of a catalyst which consists of an aluminum oxide carrier, and contains 3.7 wt. referred to the catalyst of copper in the form of a salt and traces of iron.'The catalyst has the following sieve analysis:

The catalyst's own volume is best absorbed. one is the water-tort calculation method: 1 cylinder with 2 dm 3 content is first filled with 1 dm 3 of catalyst particles and 1 dm* of 20 °C water is added to it. The mixture is shaken slightly, and some .time, until no more gas bubbles rise. The volume of the mixture now amounts to 1300 .cm 3 . 1 dm 3 (shaking volume)

of the catalyst consequently has an intrinsic volume of the catalyst part" of 300 cm"3. The total catalyst filling of o

2.8 dm 3 has a specific volume of 840 cm 3. The free gas space in the reaction tube after filling the catalyst still amounts to 3.86 dm<3.>

Now blue is seen above the lower gas inlet pipe through first free air in a quantity of 60 normal-dm 3 per-. hour and tempering hose one in the reaction chamber is heated with a heating liquid. After 25 minutes, an air temperature of 185°C is measured in the reaction tube, which does not change during the next 5 minutes. If the amount of air blown in is increased to 90

3-1

Ndm'-. h and at the same time introduced over other free mixture of

3-1 ethylene in the quantity specified below and 44 Ndm. h chlorine.rhydrogen gas. Immediately thereafter, it also begins by introducing 22 Ndm 3. h -1 chlorine gas over the ball-equipped gas line pipe which is placed in the connection (A) furthest removed from the other free, at the same time, ethylene is fed in in the amount specified further below through the ball-equipped gas introduction tube which is placed in the middle connection (B) into the reaction tube. (The socket closest to another frit is not used, it is closed with a cork). All gases fed into the reaction tube are preheated to 60°C.

In the individual examples, a total of 44.5 Ndm 3 is supplied to the reaction tube each time. h -1 ethylene, in the following sub-quantities through the two introduction points (second frit and socket B): -

Together with the introduction of the reaction gases, the water cooler is coated with water of 14°C, and the brine cooler with coolant of -15<U>G. Of the gas washing bottles; contains water as washing liquid.

After a short time, the temperature in the reaction room is increased to 223°C. It is kept at this temperature during the further course of the process by supplying the tempering hose with coolant. The exhaust gas leaving the solar cooler has a temperature of 10°C. The experiment is continued for three hours, and after 1/3 and 2/3 of this time, the exhaust gas composition of the washed exhaust gas is determined gas chromatographically. The gases oxygen, carbon monoxide, carbon dioxide and ethylene are used the thermal conductivity detector for all other gases specified below a flame ionization detector. The mean value of both analyzes is e.g. 1 and - 7 summarized - in the table II below as it from oxygen values

above the used air, the noble gas element has already been subtracted.

After the test duration has elapsed, the gas supply to the reaction tube is terminated and the catalyst is blown cold with air (approximately room temperature). The condensate formed by water and salt brine cooler is combined, weighed and analyzed also gas chromatographically with a flame ionization detector. The values determined for examples 1 to 7 are listed in table I below.

For examples 1 to 7 there are the following values: Molar ratio HC1: C2H^:C12:02= 2: 2'°5: 1:0v86-Mean residence time of the gases in the reaction space: -1-3 LO s. Space-time yield in g raw-1 ,2-dichloroethane . h. dm , referred to 3.86 dm 3 reaction space.

Example 8 to l 11

The same apparatus and the same type and quantity of the same catalyst as in examples 1 to 7 are used, however, with the difference that a gas inlet pipe with a ball-shaped end is arranged in the connection (C) of the reaction pipe which is closest to another frit , so that, as already mentioned above, the ball of the gas inlet pipe lies from another, free at a distance of 17% of the reax ion space. overall length. The plug which is placed at the furthest distance from another frit, and the plug placed at a distance of 53% of the height of the reaction chamber from another frit, is not used. It is closed with cork. A mixture of 90 Ndm is introduced through the lower opening of the reactive ion tube. h air, and 22 Ndm . h-chlorine that enters over the first frit in the reaction chamber. Another part of ethylene is introduced over the other frit and over the pipe with it

spherical end LL Ndm . h chlorine hydrogen gas, and the rest the ethylene. For the individual examples, a total of L5Ndm is added each time. h - ethylene in the following sub-quantities through the two introduction points (second frit and socket C) into the reaction tube:

The temperature in the reaction room is kept constant at 222°C, test durations amount to 3 hours. Otherwise, proceed as described in example 1.

For example 8 to 11 the following values are given: Molar ratio: C^: HC1 : Cl2: 02=2:1.95:098:0.84.

Additional residence time of the gases in the reac-'

■ tion space: 4.0 s. The space-time yield in g raw-1 , 2-dichloroethane- . h -1 . dm - 3 referred to 3.86 dm 3 reaction space:

See crude 1,2-dichloroethane and exhaust gas analyses

the tables III and IV below.

In all mentioned examples (no. 1 to 11), work is carried out at normal atmospheric pressure of 97.3 kPa.

Examples 12 and 13

The apparatus used for this is constructed analogously to that used in examples 1 to 7, however with the difference that a vertical nodding tube with an inner diameter of 50 mm is used as the reaction chamber, which is equipped similarly to the glass tube: of the apparatus used for examples 1 to 7 with the following differences: That is

only present three temperature measuring points evenly distributed over the reaction tube's mantle. Set from below. and upwards, the first bo fritters are arranged as described in the apparatus for examples 1 to 7. Then follows a third fritter and then a fourth. The distance from the second frit amounts to the third frit 4.1% of the fourth frit 47% of the total inner length of the reaction space. Also at the top of the tube immediately before the taper, a fifth frit is built in which is used for pressure reduction and for retention of entrained catalyst particles with the cold prescribed in the glass apparatus for this being omitted. A pressure reduction valve is located at the reactor outlet. The gas introduction pipe with a ball-shaped head is permanently built into the reactor, as the distance from the ball to the second frit (from below) constitutes 56% of the length of the total reaction space measured between the bottom and top frit in the tube. In the upper part of the tube is placed. a measuring device.

The contents of the reaction chamber minus the volume of the built-ins (tempering hoses, gas inlet pipes and liquid or carbon header, temperature measuring sensor) amount to 1500 cm 3. After the reactor outlet after the pressurization stage, there is a water and brine cooler, as well as chlorine hydrogen - washers as discussed in examples 1 to 7.

The nickel tube is filled with 1 dm. (shake volume) from a catalyst sorn contains copper chloride on aluminum oxide and has a copper content of .4.5 wt?, referred to the catalyst. The catalyst contains no iron. and has the following sight analysis:

The catalyst's own volume is determined, as discussed earlier, according to the water displacement method to 310 cm 3. The free space available for the gas reaction amounts to 1190 cm 3.

Blows through the lower gas supply line

in the first row 60 Ndm' 3. ,h -1 air through the first (lower)

fry under pressure,' and the reactor is heated by means of temperature hose to 24-0°C. When 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, constant temperatures and pressure have been reached in the reaction tube. Now the amount of air blown in is increased to 90 dm' 3. h -1 and through the second, third and fourth frit the following amounts of gas are blown in:

The temperature in the reaction space rises and is set by introducing a cooling medium in the tempering hose in example 12 to 280°C in example 13 with 265°C and is kept constant for a further . 3 hours.

The gases introduced into the reaction chamber are preheated to 60UC. After a period of 3 hours, the gas supply is interrupted and the catalyst is blown cold in reaction with air (approximately weather temperature).

During the total test time, the water cooler is flowed with water of +12°C and the brine cooler with coolant of - 20UC.' Of the gas leaving the brine, the beer has

a temperature of 11°C.

During and after each trial, samples were taken and evaluated as described under examples 1 to 7. Determined values are listed in tables V and VI: For examples 12 and 13, the following values are found:

Molar ratio: HC1 : CgH^ (total): C-12: O2=

2 : 2.04: 1 : 0.75.

Mean residence time of the gases in the reaction space: Example 12: 55 s, example 13: 58 s. Rointidsut exchange in g raw-1 , 2-dichloro ethane : -1-3 3 . H drn , referred to 1.19 dm reaks ion space. Example 12: 181, Example 13: 182.

Claims (3)

1. Process for the production of 1,2-dichloroethane from ethylene by reaction with hydrogen chloride and inert gas containing oxygen at 180 to 300°C and 0.1 to 1.1 MPa, as well as. by reacting with chlorine to gas phase in the presence of a copper ' or solid catalyst containing copper and iron salts with subsequent cooling and distillative separation of the reaction mixture, as both chlorination reactions are carried out one after the other, in a common reaction space, which contains stirred catalyst particles, and the heat dissipated in the combined 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 quantity of the total volume of ethylene introduced into the reaction space is introduced into the zone of the reaction space in which the first chlorination reaction takes place, and the remaining 2 to 6% of the total quantity of the total volume of ethylene introduced into the reaction space is introduced into the part of the reaction space in which other chlorination reactions take place. 2. Method according to claim 1, characterized in that 95 to 60% of the total amount of the ethylene volume introduced into the common reaction space is introduced into the zone in the reaction space in which the first chlorination reaction takes place, and the remaining 5 to 4-0% of the the same amount of the total volume of ethylene introduced into the reaction space is introduced into the zone in the reaction space in which another chlorination reaction takes place. . 3. Procedure .''according to claim 1 or 2, characterized in that the reaction space is continuously flowed through by the gases to be reacted, while in a zone of the reaction space placed first in the direction of the gas's flow, separate or partially separated from each other are introduced: Hydrogen chloride, a sub-quantity of ethylene and oxygen containing inert gas, and in a downstream zone of the reaction space separated from each other, the remaining sub-quantity of ethylene and chlorine in the following ratio: 2' mol HC1, 1.8 to 2.2 mol total amount of CpH^ , 0.5 to 0.6 mol Op, and 0.79 to 1.2 mol Clp, the amount of chlorine being sized so that in the gas mixture leaving the reaction space is there less than 0.001 weight? free, elemental chlorine. L. Method according to claim 1 or 2, characterized by the fact that the reaction space through- . flow continuously of the gases that are to be reacted, as the first zone placed in the direction of the gas' flow of the reaction space is introduced: Oxygen-containing inert gas and chlorine as separated from this, a partial amount of ethylene and a subsequent zone of the reaction space in the direction of flow, hydrogen, and the remaining partial amount of ethylene in the following proportions: 2 mol total amount of CpH^ , 0.9 to 1.2 mol Clp, 1.6 to 2.3 mol HC1 pg 0.35 to 1.3 mol Op, where the amount of oxygen or hydrogen chloride is dimensioned so that in the gas mixture that leaves the reaction space, less than 0.001 weight? free,, elemental chlorine.