CS202555B2 - Catalyctic mixture for making the chlorinated hydrocarbons notably 1,2 dichlorethan,by way of the oxychlorination with the ethylene - Google Patents

Description

The present invention provides a catalyst composition for the production of chlorinated hydrocarbons, in particular 1,2-dichloroethane, by oxychlorination of ethylene.

It is known that hydrocarbons such as ethylene can be chlorinated by reacting with hydrogen chloride and oxygen-containing gases, in particular with air in the presence of a catalyst at elevated temperatures and pressures. This process is commonly referred to as oxychlorination or the Deacon process and typically employs a catalyst comprising at least a divalent metal chloride, typically on a porous refractory support.

The most common catalyst for such processes includes copper chloride on a granular support such as activated alumina, silica, a mixture of alumina and silica, diatomaceous earth, etc. The most commonly used carrier is activated alumina in some of its numerous forms. In addition, the catalyst may contain additives such as alkali metal chlorides, rare earth metal chlorides, and other metal compounds to aid the desired reaction and / or prevent side reactions. Potassium chloride is particularly used as an additive to such catalysts when 1,2-dichloroethane is to be prepared from ethylene, since potassium chloride is known to suppress the formation of ethyl2 chloride. However, a small amount of potassium chloride is used, since this compound also tends to reduce the activity of the catalyst with respect to the main reaction.

In carrying out such oxychlorination using a fixed bed catalyst, one of the main considerations is to control the reaction temperature. The oxychlorination reaction itself is highly exothermic and, moreover, control of the reaction temperature is made difficult by the catalyst bed having a low thermal conductivity.

These two factors imply the risk of undesirable localized locations of extremely high temperature in the catalyst bed. Many measures have already been proposed to avoid either wholly or at least as much as possible the occurrence of these exceptionally high localized temperatures. For example, it has been suggested to control the temperature by adjusting the ratio of the amount of reactants or diluting the feed with inert gas or excess of one or more reacting gases, using a tubular reactor with controlled external cooling and / or tubes of different diameters, or diluting the catalyst particles with inert particles, or varying the size of the catalyst particles and / or inert particles.

In particular, when the reaction is carried out in tubular reactors, it is known - as is at 202555

202355 example described in U.S. Pat. No. 3,184,515 - that the problem of undesirably high local temperatures does not occur throughout the reactor. This is due to the very nature of the oxychlorination reaction, which gradually fades in the flow direction of the reaction mixture. At the inlet of the catalyst bed, the reaction proceeds rapidly and with high intensity and requires control of both temperature and hot spot locations (highest temperature points) in the catalyst bed. However, as the reactants pass through the catalyst bed, the reaction becomes somewhat less violent as oxygen is consumed. This is particularly the case when, as is known, oxychlorination is carried out in at least two sequentially connected catalytic reactors, wherein the total amount of air (or oxygen) supplied is distributed between the individual reactors. Therefore, as the feed oxychlorination feed reacts, oxygen is consumed towards the exit of each reactor, and the risk of an undesired reaction or too high a local temperature in that zone is less than in that part of the reactor closer to the reactor inlet.

One solution that has been proposed to achieve acceptable conversions and acceptable selectivity to dichloroethane, as well as to achieve adequate control of reaction temperatures and generation of high local temperatures, is to use a catalyst mixture whose active ingredient - catalyst - is diluted with inert particles. The inert particles may be, for example, silica, alumina, graphite, glass beads, etc.

In some production processes, the ratio of catalyst amount to solvent amount in the oxychlorination reactor was still not the same. It is desirable to have a less concentrated catalyst on the reactor inlet side due to the risk of undesired reactions or high local temperatures. However, further from entering the reactor as the reaction progresses and becomes less violent, these dangers are no longer as pronounced and, conversely, it would be desirable to have a more active catalyst to continue to stimulate the reaction with continued oxygen consumption.

When using dilute catalysts, it is therefore common to divide the catalyst bed into at least two zones, each having a different ratio of catalyst amount to solvent amount, wherein the ratio of catalyst amount to solvent amount increases towards the exit end of the reactor.

For example, U.S. Pat. No. 3,184,515 discloses a process (Example 1J, operating a dilute catalyst, wherein the tubular reactor is divided into four zones, the first containing 7 volume% catalyst and 93 volume% graphite diluent, the second zone containing catalyst and diluent). 15: 85 by volume, the third zone contains a 40:60 mixture of both, and the fourth zone contains only a catalyst, but in another variation, a very active catalyst can be placed at the reactor inlet to initiate the reaction, followed immediately by a much less active a catalyst to prevent hot spots from forming in the adjacent reaction zone.

However, the use of a dilute catalyst as described above has several disadvantages. First, it requires filling the catalyst into several different reaction zones and thereby mixing several catalyst / diluent mixtures in different proportions. More importantly, however, the fact that mixing the catalyst and the diluent can produce an uneven mixture. It is therefore likely that undesirably high local temperatures will arise as a result of greater concentration of catalyst particles in a particular region of the reaction zone if the mixing is not carried out sufficiently thoroughly. In addition, in many cases the diluent particles generally do not have the same size or shape as the catalyst particles.

For example, it has been proposed to dilute cylindrical or spherical catalyst particles with diluent particles of different shape or size. In such cases, the resulting mixture does not provide a reasonably uniform surface to the reactants and the pressures and / or pressure drops that occur during the reaction may be disadvantageous. Even if the diluent particles have the same shape or size as the catalyst particles, it is nevertheless likely that the diluent and the catalyst will not be sufficiently mixed and that hot spots may be generated; however, there is still the disadvantage of producing different catalyst-diluent mixtures for the individual reaction zones.

Another suggested solution was to use a catalyst, with or without diluent particles, in which the particle size decreases from the reactor inlet to the reactor outlet. Such a solution is described in U.S. Pat. No. 3,699,178. However, even if a catalyst without a diluent is used, it requires a larger particle size, and furthermore at least two, and most likely three, at least two, and most likely three or four different catalysts, in order to achieve the objectives of this solution. In an alternative embodiment of this solution in which the catalyst is mixed with diluent particles, the disadvantage of having to prepare different sized catalyst particles is the additional disadvantage of using diluent particles.

The purpose of the invention is to provide a catalyst mixture for the production of 1,2-dichloroethane by oxychlorination of ethylene, the use of which would avoid the above drawbacks.

Another object of the invention is to provide a catalytic mixture for the production of 1,2-dichloroethane by oxidation of ethylene, the use of which can control the occurrence and temperature of hot spots without difficulty.

It is also an object of the present invention to provide a catalyst mixture for the production of 1,2-dichloro22555 ethane by oxychlorination of ethylene at high degrees of hydrogen chloride conversion.

It is a further object of the present invention to provide a catalyst composition for the production of 1,2-dichloroethane by oxychlorination of ethylene, the ingestion of which can maintain a practically uniform pressure drop over a reasonable period of time.

Yet another object of the invention is to provide a catalyst composition for the above production, wherein the selectivity of the conversion of ethylene to 1,2-dichloroethane is acceptably high and a minimum excess of reactants such as ethylene and / or air can be employed.

It is also an object of the present invention to provide a catalyst composition for the above-mentioned production, wherein high flow rates of the reactants can be used.

Finally, it is an object of the present invention to provide a catalyst composition for the oxychlorination of ethylene using either oxygen or air as the oxygen-containing gas.

In summary, it is an object of the present invention to provide a novel catalyst composition whose use in the oxychlorination of ethylene to 1,2-dichloroethane is associated with the above advantages.

The invention therefore relates to a novel catalyst composition for the production of chlorinated hydrocarbons, in particular 1,2-dichloroethane, by oxychlorination of ethylene, comprising copper chloride and potassium chloride deposited on a support consisting of spherical particles of activated alumina, which catalyst composition is characterized in that the support has a specific BET surface in the range 225 to 275 m ² / g, at least 90%. abrasion hardness, total pore volume determined by nitrogen in the range 0.3 to 0.6 ml / g, mean pore diameter in the range 50 to 100 A, with 20 to 50% of the pore volume being formed, pores with a diameter in the range The catalyst composition of the invention also exhibits an X-ray diffraction pattern having peaks at 1.39, 1.98 and 2.34 A, a ratio of peak intensity at 1.39 A to peak intensity at 1.98 A, respectively. it is in the range of 1.5: 1 to 5: 1, and when bound with hydrogen fluoride, the boundaries between the grains are not discernible. Preferably said intensity ratio is maximally 2: 1.

The catalyst mixture according to the invention is characterized by a high structural integrity. Ethylene is converted to 1,2-dichloroethane at a high degree of conversion and selectivity with good hot spot controllability and very low pressure drop over long periods of time using the catalyst composition of the invention in a series of three reactors in which the catalyst composition is used practically without inert and the content and weight ratio of cuprous chloride to potassium chloride in the catalyst varies within each of the three reactors. In each of the first two reactors, the catalyst bed is divided into two zones, with the catalyst in the zone closer to the reactor inlet preferably having a somewhat lower copper chloride content and a higher potassium chloride to copper chloride weight ratio than the catalyst in the zone which is closer to the exit of the reactor.

The invention discloses a catalytic mixture for carrying out an oxychlorination process comprising said catalyst placed in the reactors as described above.

The process for the oxychlorination of ethylene, using the catalyst composition of the present invention in a fixed bed at a temperature in the range of 180 to 340 ° C, consists in reacting ethylene, hydrogen chloride and a first portion of the oxygen-containing gas in contact with the first reaction zone. a catalyst bed of virtually undiluted catalytically inert particles containing copper chloride and potassium chloride deposited on spherical activated alumina particles, the first catalyst bed being divided into two portions downstream of the reactants, of which the first portion constitutes about 45 to 74% of the bed and the second portion comprises about 25 to about 55% bed, the first portion containing 4.5 to 12.5% copper chloride by weight and 1.5 to 7% potassium chloride by weight by weight of copper chloride to potassium chloride in the range of 1.5 : 1 to 4: 1, and the second part contains 12 up to 25% by weight of cuprous chloride and 0.5 to 4% by weight of potassium chloride in a weight ratio of copper chloride to potassium chloride in the range of 5: 1 to 15: 1, - reacting the reaction products obtained in the first reaction zone in a second reaction zone; with a second portion of the oxygen-containing gas by contact with a second catalyst bed practically undiluted by catalytically inert particles and containing copper chloride and potassium chloride deposited on the spherical activated carbon dioxide particles, the second catalyst bed being divided into two portions downstream of the reactants; about 45 to 75% of the bed, and the second part about 25 to 55% of the bed, the first part of the bed containing 5.5 to 15% by weight of copper chloride and 1 to about 5% by weight of potassium chloride by weight of copper chloride to potassium chloride in the range of 2: 1 to 6: 1, and the second part of the bed contains 12 to 25% by weight of copper chloride and 0.5 to 4% by weight of potassium chloride in a weight ratio of copper chloride to potassium chloride in the range of 5: 1 to 15: 1; and - in the third reaction zone, the reaction products obtained in the second reaction zone are reacted with a third part of the oxygen-containing gas by contact with a third catalyst bed of virtually undiluted catalytically inert particles and containing 12 to 25% by weight of cuprous chloride and 0.5 to 4 % by weight of potassium chloride deposited on the spherical particles of activated alumina in a weight ratio of copper chloride to potassium chloride in the range of 5: 1 to 15: 1, with ethylene being used in a 35% stoichiometric excess over hydrogen chloride; up to 25% of a stoichiometric excess over the hydrochloride All of the gaseous feedstock and all gaseous feedstocks are preheated to a temperature in the range of 120 to 220 ° C prior to introduction into the reaction zone.

The reaction system for the oxychlorination of ethylene in the presence of a catalyst composition of the invention, comprising copper chloride and potassium chloride deposited on spherical particles of activated alumina, comprises - a first reaction zone consisting of a first catalyst bed divided in two portions downstream of the reactants; about 45 to 75% of the bed, and the second part about 25 to 55% of the bed, the first part containing 4.5 to 12.5% copper chloride and 1.5 to 7% potassium chloride by weight of copper chloride to chloride potassium chloride in the range of 1.5: 1 to 4: 1, and the second part contains 12 to 25 wt. potassium chloride in a weight ratio of copper chloride to potassium chloride in the range of 5: 1 to 15: 1, - a second reaction zone consisting of a second catalyst bed divided in two parts downstream of the reactants, the first part constituting 45 to 75% bed; a portion comprising 25 to 55% of the bed, the first portion containing 5.5 to 15% by weight of cuprous chloride and 1 to 5% by weight of potassium chloride in a weight ratio of copper chloride to potassium chloride in the range of 2: 1 to 6: 1; the bed contains 12 to 25% by weight of cuprous chloride and 0,5 to 4% by weight of potassium chloride in a weight ratio of cuprous chloride to potassium chloride in the range of 5: 1 to 15: 1 and - a third reaction zone consisting of a third catalyst bed containing 12 to 25% % copper chloride and 0.5 to 4% potassium chloride by weight p copper chloride to potassium chloride in the range: 1 to 15: 1.

The attached drawing shows a flow diagram of the production of 1,2-dichloroethane by oxychlorination of ethylene using the catalyst composition of the invention.

The catalyst composition of the invention is prepared by conventional impregnation of the support using aqueous solutions of cuprous chloride and potassium chloride, as described in more detail in the Examples below. The impregnated carrier is activated alumina with a large specific surface area with spherical particles, i.e., alumina with a specific surface area.

BET of at least 100 m ² / g, preferably in the range of 225 to 275 m ² / g, with at least 90% abrasion hardness, total nitrogen pore volume in the range of 0.3 to 0.6 ml / g with a mean a pore diameter in the range of 50 to 100 A, with 20 to 50% of the pore volume being composed of pores with a diameter in the range of 80 to 600 A This alumina is further characterized by an X-ray diffraction pattern having three major maxima: diffusion maxima at 1.39; 1.98 A and a further peak at 2.34 A, with a ratio of peak intensities at 1.39 A peak at 1.98 A ranging from 1.5: 1 to 5: 1. This alumina also has virtually imperceptible boundaries between the grains after etching with hydrogen fluoride. It has been found that carriers of these properties have good structural stability over long periods of operation. Examples of suitable carriers of this kind are commercially available alumina (designated HSC-114 and SCM-250).

As is evident from the attached drawing, performs the production of 1,2-dichloroethane by oxychlorination of ethylene using a catalyst composition according to the invention in three series-connected reactors, designated R ^1, R ² and R ^3rd Each of these reactors comprises a catalyst bed 12, 14 and 10. Preferably, tubular reactors with tubes filled with catalyst mixture are used.

In the reactor R ¹ the catalyst bed is divided into two portions in the direction of flow of reactants. The first portion, on the reactor inlet side, comprises 45 to 75%, preferably 55 to 65% of the length of the catalyst bed and comprises a catalyst having 4.5 to 12.5% by weight, preferably 5 to 8% by weight, and in particular 5, 5 to 6.5% by weight of cuprous chloride and 1.5 to 7% by weight, preferably 2 to 4% by weight, and in particular 2.7 to 3.3% by weight of potassium chloride, wherein the weight ratio of copper chloride to potassium chloride is in the range of 1.5: 1 to 4: 1, preferably in the range of 1.5: 1 to 3: 1 and in particular 2: 1.

The second part of the catalyst bed, at the outlet end of the reactor, comprises 25 to 55 percent, preferably 35 to 45 percent of the bed length, and comprises a catalyst having 12 to 25 wt%, preferably 15 to 20 wt% cupric chloride and 0.5 to 4 wt%. %, preferably 1.5 to 3 wt. % of potassium chloride, wherein the wt. The ratio of cuprous chloride to potassium chloride is in the range of 5: 1 to 15: 1, preferably in the range of 5: 1 to 12: 1 and in particular 10: 1. The catalyst bed 12 of the reactor R ¹ thus comprises two types of catalyst compositions: a first catalyst composition in a portion of the bed at the reactor inlet, which is characterized by a relatively lower efficiency in order to ensure that the reaction does not become uncontrollable, in its initial stage and a second catalyst composition having a higher copper chloride content, and hence higher activity, at the reactor exit side, which ensures the reaction continues as the reaction begins to lose intensity due to oxygen uptake.

The reactor R ² comprises a catalyst bed 14 which is also divided into two parts. The first part of the catalyst bed on the inlet side of the reactor comprises 45 to 75%, preferably 55 to 65% of the length of the bed, and the second part of the bed on the outlet side of the reactor comprises 25 to 55%, preferably 35 to 45% of the length. bed.

The catalyst mixture in the first part of bed 14 in reactor R ² may be somewhat stronger or more active than the catalyst mixture in the first part of bed 14 in reactor R ¹ , since the reaction has already progressed in part. In the reactor R ² , the catalyst mixture in the first part of the bed contains 5.5 to 15% by weight, preferably 7.5 to 12.5% by weight and in particular 9 to 11% by weight of cuprous chloride and 1 to 5% by weight, preferably 1.5 to 3.5% by weight and in particular 2.5 to 3.5% by weight of potassium chloride, wherein the ratio by weight of cupric chloride to potassium chloride is in the range of 2: 1 to 6: 1, preferably in the range of 3: 1 to 4: 1 and especially 10: 3 (3.3: lj. like the reactor R ¹ contains the second portion of the catalyst bed of the reactor ^R2 a stronger catalytic mixture having from 12 to 25 weight percent, preferably 15 to 20% by weight cupric chloride and 0.5 to 4% by weight, preferably 1.5 to 3% by weight of potassium chloride, wherein the weight ratio of copper chloride to potassium chloride is in the range of 5: 1 'to 15: 1, preferably in the range of 5: 1 to 12 : 1 and in particular 10: 1.

Like in the reactor R ¹ is a danger of undesirably high local temperatures in the bed portion lying closer to the reactor outlet, much smaller than in the section on entering the reactor, whereas the reaction loses in intensity in proportion as the gases proceed catalyst bed, and therefore it is possible, and indeed, a more active catalyst composition should be used to achieve the highest conversion.

In both R ¹ and R ² reactors, the weight ratio of potassium chloride to cuprous chloride is preferably higher in the first part of the catalyst bed than in the second part.

Upon entry of the reactants into the reactor R ³ of the reaction has progressed to a large extent and completeness likelihood undesirably high local temperature is much lower than of the reactors R ¹ and R ^2nd Therefore, the entire reactor bed R ^{3 may} consist of a more active catalytic mixture as used in the lower parts of beds 12 and 14, i.e. a catalyst mixture containing 12 to 25% by weight, preferably 15 to 20% by weight, cuprous chloride and 0.5% by weight. up to 4% by weight, preferably 1.5 to 3% by weight of potassium chloride, the weight ratio of copper chloride to potassium chloride being in the range of 5: 1 to 15: 1, preferably 5: 1 to 12: 1, and in particular 10: 1. It is also possible in the reactor R ³ and / or in those parts of the catalyst beds 12, 14 lying closer to the exit of the reactors.

R ¹ and R ² use such catalyst mixtures that have even a lower potassium chloride content and a higher weight ratio of copper chloride to potassium chloride.

To produce 1,2-dichloroethane using the catalyst composition of the present invention, hydrogen chloride gas preheated in preheater 22 is supplied via line 1. Ethylene preheated in preheater 21 is supplied via line 2 and mixed with the supplied hydrogen chloride in line 1. Gas is supplied through line 3. containing oxygen, which may be air, molecular oxygen, or oxygen-enriched air, and is divided into three portions discharged via lines 3a, 3b and 3c.

The division may be in three equal or non-identical parts. Part of the withdrawn tube 3a is combined with a mixture of hydrogen chloride and ethylene in conduit 1, wherein the resulting mixture then goes to the reactor ^R1 in line 4. The temperature of the supply of raw material gas is generally in the range from 120 to 220 ° C, preferably from 135 to 180 ° C. The feedstock passes through a catalytic bed 12, which - as explained above - preferably consists of a catalytic mixture in tubes and leaves the reactor via line 5.

The reaction products from the reactor ^R1, via conduit 5, are connected in the pipe 3b, the second portion of oxygen-containing gas, and fed to reactor ^R2 via line 6, where they come into contact with the catalyst bed 14. The reaction products from the reactor R ² are extracted via line 7, mixed in line 3c with the third part of the oxygen-containing gas and fed via line 8 to the catalytic bed 16 of reactor R ³ .

The reaction products from the reactor R ³ are removed via line 9, preferably cooled in a heat exchanger 23 and condensed in a condenser 24. Condensed reaction products are withdrawn from this condenser via line 10; Composed primarily of 1,2-dichlorethylene with a small amount of ethylene chloride and other chlorinated hydrocarbons.

As a rule, the production is carried out under a positive pressure in the entire system in the range from 0.2 to 0.69 MPa, preferably from 0.27 to 0.62 MPa. In order to control the temperature in the reactor R ^1, R ² and R ^3, the reactors are preferably constructed as jacketed reactors, with the jacket surrounding the tube or catalyst beds contains a heat transfer fluid, e.g., boiling water, steam or Dowtherm liquid. The reaction is usually carried out at temperatures in the range of 180 to 340 ° C, preferably in the range of 235 to 300 ° C. In the reactor R ¹ is the hot spot temperature is usually maintained below 330 ° C, preferably below 300 ° C. In the reactor R ² , the temperature of the hot spots is kept below 330 ° C, preferably also below 300 ° C, and in the reactor R ³ the temperature of the hot spots is usually kept below 320 ° C, preferably below 300 ° C. Another important factor is the control of hot spots in the reactors. In each reactor, the hot spots should be at the inlet end of the catalyst bed. In reactors R ¹ and R ² , the hot spots should actually be located on the inlet side in the first, i.e., less and less, part of the bed. If hot spots occur in an area lying downstream of the bed, it is an indication that the reaction proceeds too slowly in the bed, i.e. the catalyst is used inefficiently. In addition, if hot spots occur in an area too far away from the bed exit, this may result in a cumulative effect along with a reaction promoting the effect of the stronger catalyst in the second portion, which may result in an undesirably high temperature level at that location.

The distribution of the oxygen-containing gas into the three conduits 3a, 3b and 3c may be such that all three reactors receive the same amount or, if desired, the amounts supplied to the different reactors may be different. Changing the amount of gas supplied to each of the reactors may affect the temperature and hot spot locations of the reactor.

For clarity, the attached drawing shows a system where the reactants pass through all three reactors from top to bottom, i.e., they are fed to the top of the reactor and removed as a reaction product from the bottom of the reactor. However, production can also be carried out in reactors in which the reactants are fed at the bottom and the reaction products are discharged from the top, with suitable means for retaining the catalyst mixture. By designing the reactors alternately with the downstream and upstream reactants, the pipeline costs can be reduced. For example, in reactors R ¹ and R ³ , the reactants may be led upwards and in the reactor R ² may be passed downwards. It is also possible to reverse the solution when the reactants in the reactors R ¹ and R ³ may flow downwardly in the reactor R ² upwards.

Not all of the specified hydrogen chloride need be fed to the first reactor; a portion may be separated and fed to the reactor R ² together with a second portion of the oxygen-containing gas.

Typically, production is carried out using an excess of both oxygen-containing gas and ethylene relative to hydrogen chloride to ensure the most complete conversion of hydrogen chloride. When using air, it is desirable to work with as little excess of these reactants as possible to avoid transporting large quantities of gas. In this case, an excess of ethylene of 35%, preferably 5 to 20% is used, and an excess of gas is maintained at most 25%, preferably 5 to 20%.

The use of the catalyst composition of the invention is described herein by way of example of oxychlorination wherein the oxygen-containing gas is air. However, both the catalytic composition and its configuration and production method as described above are also suitable for a process using molecular oxygen or oxygen-enriched air.

In one such process, as described in U.S. Patent 3,892,816, a large excess of ethylene is used relative to oxygen and hydrogen chloride to avoid overly intense reaction and excessively high hot spot temperatures. Excess ethylene is preferably recovered from the reaction product and returned to the oxychlorination reactors; in such a process, it is not necessary to work with as little ethylene as possible.

When used in the circulating system for hydrogen chloride of a steel plant, small amounts of ferric chloride may be generated, which are fed into the catalyst mixture with the feed stream. Corrosion of the oxygen-containing gas feed systems can result in iron oxides which can be converted to ferric chloride in the reactor by reaction with hydrogen chloride. The catalyst mixture can contain small amounts of iron as impurities; however, it has been found that this species of ferric chloride tends to contaminate and deactivate the copper chloride forming the oxychlorination catalyst even in small amounts. Thus, in one variation of the process, contamination of the catalyst mixture with ferric chloride is prevented by the process described in U.S. Patent No. 4,000,205, wherein either the hydrogen chloride stream or the feed gas mixture is passed through a bed of activated alumina impregnated with 5-25% by weight, preferably 10 to 20 percent by weight of sodium chloride or potassium chloride. This bed may be located in the hydrogen chloride line 1 either upstream or downstream of the preheater 22 or in the line 4 through which the already mixed feedstock is fed. An alternative may be that the bed positioned within the reactor ^R1 in the space 30 adjacent the inlet to the reactor. In a preferred embodiment, when using tubular reactors may be the material forming the bed is filled into the portions of the tubes of the reactor ^R1, adjacent the inlet to the reactor before the catalyst mixture comprising cupric chloride in the direction of flow of reactants, and can be separated from the catalyst mixture nets or similar devices to prevent the removal of the removed ferric chloride into the copper (I) chloride catalyst mixture. In a preferred embodiment, the same alumina is used for this bed as well as for the catalyst mixture support.

It should be noted that the operation of each of the reactors R ¹ and R ² are only partly affected by the operation of the second reactor. For example, if the occurrence or temperature of hot spots in either of the R ¹ and R ² reactors temporarily exceeded the desired range, this would not mean that operation in the second reactor would necessarily be adversely affected, or if it were, its operation could be separately controlled by adjusting the coolant temperature, by adjusting the distribution of the amount of air fed to both reactors and the like. Similarly, it is possible, although much less preferred, to use one of the two reactors R ¹ and R ² of the above-described catalyst composition in amounts and in those parts of the bed, as this has been described, and in the second of these re202555 actuators to use another suitable but probably less effective catalyst.

This arrangement would not be as advantageous in terms of throughput, pressure drop, conversion, selectivity, etc., but could be necessary in case of necessity or temporary unavailability of the catalyst composition of the invention.

The following examples serve to illustrate the invention in various embodiments and variations, but the scope of the invention is not limited thereto.

The catalyst mixtures used in the examples below are obtained as follows:

A certain amount of dry, impregnated spherical alumina is placed in a beaker and weighed. Aluminum oxide (designated HSC-114) having the following characteristics is used:

Specific surface area, BET 250 + 25 m ² / g Bulk density 0.592 to 0.704 g / cm ³ Loss on ignition (300 ° Cj max. 5% by weight Abrasion hardness Minimum 90% pore volume, determined by nitrogen

0.44 ml / g mean pore diameter, BET 64 to 70 A pores with a diameter ranging from 80 to 600 A to 37% of the total pore volume screen analysis (Tyler Sieve Set) + 3 mesh max.

25 to 70 wt.

25 to 70 wt.

- 5, + 6 mesh max.

- 6 mesh max.

The x-ray diffraction pattern is characterized by three major maxima: 1.39, 1.98 and 2.34 A. MSaxima at 1.39 and 1.98 A are indistinct. The X-ray diffraction pattern of χ-alumina as shown in ASTM 10-423 is characterized by a major maximum at the same values. However, according to ASTM 10-423, the peak intensities of 1.39 and 1.98 A are approximately the same, while in the flexural patterns of the catalyst compositions of the invention used in these examples, the intensity of the maixima at 1.39 A is about twice that of , 98 A.

Results of this kind indicate that the carrier consists of (crystalline) alumina and an amorphous form of alumina. The amorphous form is believed to be β-alumina, whose X-ray diffraction pattern of the new radiation is characterized by a strong broad maximum at 1.40 A.

Further investigation of the microstructure of the catalyst mixture is carried out by etching with hydrogen fluoride. Samples of the new and used catalyst mixture are placed in a separate sample container and overlaid with epoxy resin. Then the samples are cut, polished and chemically etched on a cross-section for 2 to 5 minutes with a 20% hydrofluoric acid solution at room temperature. Observations are made after 20 seconds and 4 minutes at 21X magnification and after 5 minutes at 85X magnification. Even after 12 minutes after etching, the boundaries between the grains cannot be detected.

Water is added to the beaker in small amounts, mixing the contents of the beaker after each water addition with a glass rod until the water is soaked into the alumina. As more water ceases to absorb, the alumina is saturated with water. From the resulting weight of the beaker, the weight percent of water absorbed can be determined. From this, the amount of water absorbed by the weight of the carrier can be determined.

Weigh such an amount of dry alumina as the carrier to be impregnated with water. Next, weigh the amounts of cupric chloride and potassium chloride, which represent the desired percentages, based on the dry carrier, and dissolve these in water. An additional amount of water is added to the resulting solution so that its total amount reaches the absorption capacity of the carrier as predetermined. It should be noted that this volume may need to be reduced by approximately 3% to avoid a large excess of impregnation solution not absorbed by the carrier. The carrier and the impregnating solution are introduced into a drum, which is sealed, sealed, and rotated, held for 15 minutes to achieve complete impregnation.

After 15 minutes, the rotation of the drum is interrupted, the drum is opened immediately, and the saturated alumina particles are transferred to glass or ceramic hazel in a layer of thickness.

7,5 cm. The hazelnuts are placed in a forced air oven; their contents are dried at 140 ° C for 16 to 24 hours. The catalyst mixture is then spilled and allowed to cool and then stored in airtight containers. The amounts by weight of the salts in the catalyst mixture thus prepared are in the range of 0.5% of the desired values.

The accuracy of the contents can be improved by carefully drying the alumina before weighing. The impregnation should be followed immediately by drying; the delay of this operation may adversely affect the physical structure of the resulting catalyst composition.

The experimental data in the following tables were obtained using the catalyst mixtures prepared as described above in a device arranged as shown in the accompanying drawing. Each of the actuators re202555 R ^1, R ² and R ³ consists of a nickel tube of length 375 cm and 2.5 cm in diameter, fitted over the entire length of the jacket in the form of a steel tube with a diameter of 3.75 cm, wherein the reactants flow through the reactor from above down. Reaction heat is removed by the Dowtherm heat transfer fluid flowing through the annular space between the two tubes. The temperature of the hot spots and the region of their occurrence within the catalyst bed of each reactor is measured by means of a thermocouple that can be moved inside a 360 cm long thermal probe, which is introduced below each reactor.

As can be seen from the attached drawing, hydrogen chloride is supplied to the system via line 1 through a preheater 22. Ethylene is supplied to the system via line 2 through a preheater 21. Air is supplied through line 3 and distributed to lines 3a, 3b and 3c, fed to the reactor ^R1, the air in the duct 3b to the reactor R ² and the air in the pipe 3c of the reactor R ^3rd

The raw material mixture fed to the reactor R ¹ is, after preheating temperature of about 140 degrees Celsius. Adjust 100% throughput, which is equivalent to 18.8 grammes of hydrogen chloride per hour per cm ² . The feed rates of air and ethylene are expressed in percent of excess relative to hydrogen chloride, assuming a stoichiometric reaction to produce 1,2-dichloroethane.

The gas leaving reactor R ³ is cooled in a glass, water-cooled condenser, after which all unreacted hydrogen chloride is condensed as the aqueous phase and most of the 1,2-dichloroethane produced is relatively pure (approximately 98.5% organic). The conversion of hydrogen chloride is determined by titration of the aqueous phase with sodium hydroxide to determine the percentage by weight of hydrogen chloride in the aqueous phase.

The non-condensed gas with a water-cooled condenser is subjected to gas chromatography. The amounts of oxidized ethylene and the resulting ethyl chloride are calculated from the analyzes, both of which are expressed as a percentage of the ethylene feed.

Table 1 summarizes the conditions of a single test performed using the catalyst compositions of the present invention, preferably. The test, which lasted a total of 320 hours, was divided into two parts; in the first part, lasting for the first 298 hours, the apparatus operated at 125% throughput of hydrogen chloride and other reactants. For the last 22 hours, the device has been operating at 100% throughput.

The catalyst mixtures used were listed in Table I as catalyst mixtures A, B and C. The required percentages of cupric chloride and potassium chloride were as follows:

Catalytic mixture A: 6.0 + 0.5% CuCl2 3.0 + 0.3% KCl (2: 1 ratio by weight) Catalytic mixture B: 10.0 + 0.7% CuCl2 3.0 + 0.3% KCl (3.3: 1 w / w) catalyst mixture C: 18.0 + 1.8% CuCl 2

1.8 + 0.25% KCl (10: 1 weight ratio) (Table 1 shows the amounts determined by the analysis of the catalyst mixtures. The amount of cupric chloride and potassium chloride in Catalyst C varied somewhat as catalyst mixtures from several different preparations.)

For all three reactors, the catalyst bed length was 337 cm, the first (upper) portion being 202 cm (60% of the bed length) and the second (lower) portion being 135 cm (40%) of the total bed length. The first part of the reactor R ¹ being a catalyst composition A (receptacle 12); catalytic mixture B (bed 14) was used in the first part of reactor R ³ and catalyst mixture C was used in reactor R ³ and in the lower parts of reactors R ¹ and R ³ .

Table I

Catalytic mixture:

copper chloride, wt. % potassium chloride, wt. % iron as Fe, ppm sulfate as SO4, wt. % silica as S1O2, wt. % loss on heating at 300 ° C, wt. % hardness, weight% sieve analysis, wt. % + 3 + 4 + 5 + 6 BET specific surface area, m ² / g total pore volume determined by nitrogen ml / g pore volume ranging from 80 to 600 A,% of total pore volume mean pore diameter (BET), A

ABC

6.1 9.9 18.4—19.6 3.08 3.08 1.84—1.92 <800 <800 <800 <0.5 <0.5 <0.5 <0.25 <0.25 <0.25 <6.0 <6.0 <6.0 min. 93 94 95 max. 3 max. 3 max. 3 min. 40 min. 40 min. 40 max .. 45 max .. 45 max .. 45 max. 5 max. 5 max. 5 204 196.5 149—165 > 0.25 > 0.25 > 0.25 30 30 30 60 60 60

During the first 60 hours of the test, various factors causing data instability were adjusted and stabilized. Similarly, the period from 265 hours to 298 hours, which was included in the two periods of the overall test, was dedicated to re-stabilizing the pilot plant after a one-month interruption of operation between the two test periods.

During operation, as shown in Table II below, system changes were made to total pressure, excess air and ethylene, and air distribution between the reactors used to determine the effect of these parameters on hydrogen chloride conversion, selectivity of the reaction to obtain 1,2- dichloroethane, and the temperature and hot spot locations. The test data and test results are given in Table II.

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Similar to Test 1 described above, other tests, designated Tests 2-9 in Table III below, were performed using different combinations of catalyst composition compositions and reaction conditions. In all cases, the catalyst bed length was 337 cm, as in Test 1.

For both R ¹ and R ² , the first zone at the top, i.e., inlet end of the reactor occupied 202 cm or 60% of the bed, while the second zone occupied 135 cm or 45% of the total bed length. The catalyst mixture in Reactor R ³ was similar to Test 1.

Table III

Exam 2 3 4 5 duration, h 64 43 54 69 excess air,% 17 17 17 17 excess C2H4,% 10—12 8—12 8—10 10 HCl throughput,% 125 125 125 125 composition of catalyst mixture: wt. % CuCl: wt. % KC1 R ¹ , first zone 6: 2 5: 2 6: 2 6: 3 R ¹ , second zone 18: 1.8 18: 1.8 18: 1.8 18: 1.8 R ² , first zone 12: 2 8: 2 8: 2 8: 2 R ^2, the second zone 18: 1.8 18: 1.8 18: 1.8 18: 1.8 HCl conversion, 0 / o 98.8—99.4 98.0—99.1 98.4—99.1 99.0 C2H4 oxidized,% 2,3-2,7 1,7- 2.3 2.2 C2H4 converted to C2H5Cl,% 1.4 1,5-2,5 1.6 1,3-1,8 temperature and location of hot spots, ° C / cm from above, average R ¹ 310 / 112.5 294/334/125 365—334 / 260—315 / 292/150 / 100—125 / 237.5: 162.5 R ² 325 / 87.5 272 / 212.5 315-335 / 105 (rise) 325—340 / 250 R ³ 302/75 260 / 45-50 305 / 137.5 245-250 / 125 255-265 / 62.5 263 / 142.5. pressure drop, MPa 313 / 87.5 0,088 0,077 0,077—0,084 0.09 Continuation of Table III Exam 6 7 8 9 duration, h 55.5 11.5 185 16.5 excess air, ° / o 17 17 17 17 excess C2H4,% 10—8 8 7 8 HCl throughput,% 125 125 125 125 composition of catalyst mixture: wt. % CuCl4: wt. % KCl: R ¹ , first zone 10: 4 12: 6.7 12: 6.7 8: 3 R ¹ , second zone 18: 1.8 18: 1.8 18: 1.8 18: 1.8 R ² , first zone 12: 3 12: 3 10: 3 10: 3 R ^2, the second zone 18: 1.8 18: 1.8 18: 1.8 18.1: 1.8 HCl conversion,% 99.7—99.0 99.4—98.2 98.5-99.4 99.3—98.3 C2H4 oxidized,% 1,4-1,9 1.3 1,3-2,4 ~ 1.5 C2H4 converted to C2H5Cl,% 1,25 1,2 ~ 1,2 -1.5 temperature and hot spot location, ° C / cm from above, average Rt 340—275 / 125 300—325 / 255—340 / 315—345 / 300/145 137.5-150 / 75-250 / 50—87.5 R ² 285 / 112.5—150 275—285 / 255—325 / 260—280 / 112.5 R ³ 272 / 137.5 260—270 / / 87,5-100 250 / 125—187.5 / 50—112,5 245—270 / 270 / 187.5 pressure drop, MPa / 100—175 0,084 0,088 / 112.5r — 187.5 0.088 0,077

In all tests 1 to 9, it is apparent that the use of the above-described catalyst composition of varying composition variations, as described above, resulted in maintaining hot spot temperatures, typically below 340% C at a throughput of 125% based on the projected throughput. The hot spots were in the areas available to control and, as can be seen, their temperature was in many cases well below 300 ° C. Equally important is the fact that the pressure drop remained practically constant throughout the reaction system, even in Test 1, the duration of which was over 300 hours overall. Therefore, there was no need to reduce the pressure to maintain control of the hot spots and the pressure drop did not increase over long periods of operation, which would indicate the breakdown of the catalyst mixture. It was also possible to keep the excess ethylene within reasonable limits even at high throughput without substantially affecting the conversion of hydrogen chloride. As can be seen from the data in Tables II and III, it was possible to work with approximately 10% excess ethylene while still achieving up to 99% conversion of hydrogen chloride.

In addition, it has been found that the catalytic composition of stepwise variable composition, as described above, is also suitable for operation at a lower than projected throughput. It follows that the catalyst composition and systems described are characterized by operational flexibility and can be used in operations in which the throughput may vary depending on conditions such as raw material supply and market requirements, ranging from substantially lower than the design capacity, to a much higher throughput than the design capacity, without the need for any adjustments.

Claims (3)

Subject Catalytic composition for the production of chlorinated hydrocarbons, in particular 1,2-dichloroethane, by ethylene oxychlorination, comprising copper chloride and potassium chloride deposited on a spherical activated alumina support, characterized in that the support has a specific BET surface area in the range of 225 to 275 m ² / g, at least 90% abrasion hardness, total pore volume, determined by nitrogen, in the range 0.3 to 0.6 ml / g, mean pore diameter in the range 50 to 100 A, with 20 to 50% pore volume Yippee YNÁLEZU consists of pores with a diameter in the range of 80 to 600 A. 2. The catalyst composition of claim 1 having an X-ray diffraction pattern having peaks at 1.39, 1.98 and 2.34 A, a ratio of peak intensity at 1.39 A to peak intensity at 1.98 A. it is in the range of 1.5: 1 to 5: 1, and when bound with hydrogen fluoride, the boundaries between the grains are not discernible. 3. Catalytic composition according to claim 2, characterized in that it has a maximum intensity ratio of 2: 1.