DE1468741B - - Google Patents

Description

The oxychlorination of ethylene to 1,2-dichloroethane can be represented by the following equations will:

4HCl + O ₂ = 2H ₂ O + 2Cl ₂

2C ₂ H ₄ + 2Cl ₂ = 2C ₂ H ₄ Cl ₂

2C ₂ H ₄ + 4HCl + O ₂ = 2C ₂ H ₄ Cl ₂ + 2H ₂ O

If substitution takes place, vinyl chloride is formed according to the following equations:

4 HCl + O ₂ = 2 H ₂ O + 2 Cl ₂

2C ₂ H ₄ + 2Cl ₂ = 2C ₂ H ₃ Cl + 2HCl

2 C ₂ H ₄ + 2 HCl + O ₂ = 2 C ₂ H ₃ Cl + 2 H ₂ O

The stage which determines the rate of the oxychlorination of hydrocarbons is oxidation of hydrogen chloride according to equation (1), which is also known as Deacon's reaction. To speed up Many types of catalysts have been proposed for this reaction, of which Chlorides or oxychlorides of copper, iron or chromium are considered to be particularly effective.

However, since the catalytic activity of these metal chlorides is not great enough, the reaction must can be carried out in the temperature range from 300 to 600 ° C. The use of such high temperatures but has the disadvantage that these chlorides volatilize, which leads to a rapid fall the activity of the catalyst. It also creates serious difficulties as a result of Corrosion of the system.

Various methods have been proposed to overcome these difficulties, z. B. the use of metal chlorides in a mixture with an alkali chloride, such as potassium chloride, as a promoter, the use of catalysts, to which In addition, a chloride of a rare earth metal has been added, or the conversion of the volatilized Part of the catalyst which leaves the reaction vessel together with the reaction product, in an aqueous hydrochloric acid solution, which is then recycled back into the reaction vessel.

As far as the known types of catalyst are concerned, none of these proposed measures has been found Proven effective enough to suppress the volatilization of the catalyst or to be able to lower the reaction temperature to a significant extent.

The method according to the invention for the catalytic oxychlorination of at room temperature liquid or gaseous monoolefin hydrocarbons at low temperature with hydrogen chloride and oxygen or an oxygen-containing gas is characterized in that the oxychlorination at 150 to 350 ° C in the presence of a catalyst which consists of copper (II) chloride, one or several alkali bisulphates and ammonium bisulphate and one of the compounds mentioned Containing carrier consists, the molar ratio of the total amount of bisulfates to copper (II) chloride ranges from 1: 0.1 to 10.

A preferred embodiment of the invention consists in using a catalyst which also contains lanthanum chloride, cerium chloride or thorium chloride or mixtures of these compounds, where the molar ratio of cupric chloride to the total amount of lanthanum chloride, cerium chloride and Thorium chloride ranges from 10: 0.1 to 1.0.

The novel catalysts according to the invention can be used at low temperatures with a high degree of efficiency can be used.

The abovementioned multiple salts of bisulfate and metal chloride are eutectics, which at fairly melt at low temperatures. In particular, this has to be achieved by adding copper (II) chloride an equimolecular mixture of sodium bisulfate and ammonium bisulfate obtained triple salt a melting point of about 100 ° C, above which the triple salt represents a stable melt. Will Copper (II) chloride is added in excess, resulting in a melt of a mixed multiple salt, in which the eutectics or the excess copper (II) chloride are suspended.

If lanthanum chloride, cerium chloride and / or thorium chloride is added to this triple salt, then the physical state does not change at temperatures above the eutectic point.

The highly effective catalyst according to the invention is used both within the composition range, in which a homogeneous eutectic mass from the above-mentioned catalyst components is present, as well as obtained within that composition range in which the eutectic is partially or completely eliminated.

When using metal chlorides as catalysts both in the Deacon reaction as well as the oxychlorination reaction, it is known that the highest activity is achieved when the catalyst is in a molten state. But if you use the known catalysts used, which consists essentially of a combination of an alkali chloride with copper (II) chloride or Iron (III) chloride exist, so it is impossible to reduce the melting point appreciably reach.

The equilibrium constant for the oxidation of hydrogen chloride given in equation (1) increases with falling temperature, and the equilibrium shifts with falling temperature towards the Product page. With the known catalysts, however, the reaction must take place at high temperatures from 300 to 600 ° C can be carried out if a sufficient reaction rate can be achieved should because the activity of the catalyst decreases at lower temperatures.

The catalysts of the invention can be used in an effective manner at low temperatures Range from 150 to 350 ° C can be used and

show, as the following examples show, even at temperatures of 150 to 200 ° C high effectiveness.

The catalysts according to the invention can be applied in the form of a melt, which is located in the pores of the support at the reaction temperature.

The catalysts of the invention offer the following advantages:

1. There is no part of the catalyst going through volatilization lost.

2. The corrosion of the system is practically suppressed.

3. The reaction temperature can be easily controlled.

4. Since the catalyst is in a molten state in the pores of the carrier, come the reacting gases always come into contact with a fresh catalyst surface and diffuse deep into the catalyst layers at high speed.

5. Since the catalyst is in a molten state, it is not subject to poisoning Effect of carbonaceous deposits.

6. Since there is no risk of coking or burning of hydrocarbons, the degree of utilization of the hydrocarbon is increased.

7. When carried out with the catalysts of the invention, the reaction proceeds at a higher rate catalytic selectivity for the products to be produced.

With regard to the molar ratio of bisulphate to copper (II) chloride, which is referred to below as R (= ratio of the total number of moles of bisulphates to the total number of moles of metal chlorides), the following should be noted: The highest activity of the catalyst is in the range of R = 0, 1 to 10.0, in particular in the range from R = 1.0 to 2.0, can be achieved. If the molar ratio R is less than 0.1, there is some volatilization of copper (II) chloride and also a decrease in the rate of the reaction. With larger values of R one not only obtains a catalyst with a lower melting point, but also the volatility of the copper (II) chloride is reduced to a much greater extent; too high a value of R , however, leads to a decrease in the copper content of the catalyst and thus also to a decrease in the reaction rate.

Now it is known that in the oxychlorination process the remaining, unreacted part of the hydrogen chloride can only be circulated with difficulty can be returned to the reaction vessel, since it is in dilute solution in the resulting from the reaction Water accrues. '

Therefore, in practice it is necessary to 'implement carry out so that only the unreacted part of the ethylene and oxygen in the Cycle is carried out by changing the degree of conversion of the hydrogen chloride per pass as far as possible, preferably to about 100%; elevated.

In order to meet this requirement "and" to make the device as compact as possible, the catalyst must not only be stable under the working conditions, but also have such a high activity that the process ¹ 'can be carried out at a high throughput rate.

Attempts have therefore been made to determine the relative catalytic activities of bisulfate and copper (II) chloride existing multiple salts and other catalysts to determine by adding chlorides of other elements, namely the chlorides of lanthanum, cerium, neodymium, Europium, yttrium, scandium, actinium, thorium, uranium, zirconium or palladium, for these multiple salts were obtained.

The test results showed that the addition of each of the above salts to the bisulfate cuprichloride catalyst increases the activity of the catalyst, regardless of whether the added metal chloride is the chloride of an element of the actinide series, the lanthanide series or one of them belonging to both groups. It has been found that of these elements, lanthanum, cerium and thorium are particularly effective and significantly increase the activity of the catalyst, so that a high value can be used for the molar ratio R.

As a result, in the case of the catalysts according to the invention which contain chlorides of lanthanum, cerium or thorium or mixtures of these compounds in the proportions given above, the molar ratio R can be increased and a higher throughput rate can be used while maintaining a high catalyst activity.

To the mono-olefin hydrocarbons which are oxychlorinated with the catalysts according to the invention are accessible, include z. B. ethylene, propylene and butylene.

The following examples explain the preparation of the inventive catalysts and their application to the oxychlorination of mono-olefin hydrocarbons.

Example la
Manufacture of the catalyst

A catalyst according to the invention can be prepared as follows: NaHSO ₄ , NH ₄ HSO ₄ and CuCl ₂ are dissolved in five times the amount of water (based on the total weight of the salts) in such amounts that the molar ratios of NaHSO ₄ to NH ₄ HSO ₄ to CuCl ₂ range from 1: 1: 0.2 to 20. Silica gel with a particle size of 0.42 to 0.84 mm is added to the solution of bisulfates and copper (II) chloride in such an amount that the resulting catalyst contains 5.4 g of CuCl ₂ per 100 ml of silica gel. The wet catalyst mass is then evaporated to dryness on the sand bath, and the bound water is driven off in the oven at 200 ° C. '■

B ice ρ i e 1 Ib; - '

Manufacture of the catalyst.

In another method, a catalyst according to the invention can be prepared as follows be: A solution of one, two or all three of the salts cerium chloride, lanthanum chloride and thorium chloride in distilled water, silica gel with a grain size of 0.42 to 0.84 mm is absorbed, and most of the water is evaporated, leaving a dry product.

_{A solution of NaHSO 4} , NH ₄ HSO _{4 and} CuCl _{2 is added} to this dry product, which contains at least one of the metal chlorides given above

added in distilled water. This also removes the bisulfate cupric chloride solution from the silica gel grains absorbed.

^{The mixture is then dried at 200 °} C. for 2 hours with occasional stirring.

When carrying out the above production process, the molar ratio of NaHSO ₄ to NH ₄ HSO ₄ to CuCl ₂ is 1: 1: 0.2 to 20 and the molar ratio of CuCl ₂ to the sum of Ce, La and Th is 10: 0.1 to 1, while the CuCl ₂ content in the end product is 5.4 g per 100 ml of silica gel in all cases.

Even if a single salt or multiple salt consisting of one, two or three of the salts KHSO ₄ , NaHSO ₄ and NH ₄ HSO ₄ , instead of the equimolecular mixture of NaHSO ₄ and NH ₄ HSO _{4 used in Examples 1 a and 1 b} is used, the molar ratio of the sum of the bisulfates to copper (II) chloride should be adjusted to 1: 0.1 to 1:10.

Example Ic Oxychlorination Procedure

Table I shows the results of the oxychlorination of ethylene in the presence of a catalyst according to the invention. For comparison with known catalysts, the table also shows the results of tests carried out under the same conditions on the one hand with CuCl ₂ and on the other hand with CuCl ₂ -KCI as catalysts.

Table I.

Catalyst composition

CuCl ₂ , g

NaHSO ₄ , g

NH ₄ HSO ₄ , g

KCl, g

SiO ₂ gel, ml

Reaction temperature ^{, 0 C}
Amount of supplied
Reaction gases

C ₂ H ₄ , m / min

HCl, m | / min

O ₂ , ml / min

Amount of generated

chlorinated ethylene,

g / hr

Conversion of HCl,% ...
Loss of catalyst through

Volatilization, g / h
Composition of
Reaction product

1,2-dichloroethane,%.

Ethyl chloride,% ....

Vinyl chloride,%

Rest,%

Catalyst *) I II III

48.6 65.0 62.0

900
200

450
300
150

37.5 98.7

97.60 1.69 0.65 0.06

48.6

45.0 900 200

450 300 150

30.0 79.3

0.5

97.00 2.80 0.06 0.14

900 200

450 300 150

10.3 28.6

1.1

24.20

74.30

0.65

0.85 The oxychlorination experiments of this example were carried out in a heat exchanger reaction tube stainless steel (18% Cr; 8% Ni) carried out, which in its middle part with a tube for preheating the gaseous feed was provided. The reaction tube was with before the start of the experiment 900 ml of catalyst have been charged.

The reaction temperature was controlled by an array of electrical thermoregulators, with whose help the temperature inside the catalyst layer was measured at two points and around around the reaction tube arranged electric heating elements were actuated, automatically at a constant rate Height held.

As Table I shows, the catalyst according to the invention not only has a much higher activity than the known catalysts, but there is also no loss of catalyst due to volatilization instead of.

Example 2

To confirm the higher activity of the catalysts of the invention at low temperatures, a further series of experiments was c under the conditions of Example 1, but at a reaction temperature of 150 ⁰ C is performed. The results can be found in Table II.

Table II

48.6

-

45 amount of chlorinated produced

Ethylene, g / hour

Conversion of HCl,%

Loss of catalyst due to volatilization, g / h

Composition of the reaction product

1,2-dichloroethane,%

Ethyl chloride,%

Vinyl chloride,%

Rest,%

Catalyst*)
I II

25.2
65.8

99.50
0.65
0
0.35

11.6

30.5

98.50.
1.16
0
0.34

*) Catalyst I = CuCl ₂ -NaHSO ₄ -NH ₄ HSO ₄

(according to the invention).
Catalyst II = CuCl ₂ - KCl (comparative catalyst).

Example 3

The results of the oxychlorination of propylene at 200 ° C. in the presence of the in Examples 1 a and Ib are given in Table III.

The flow rates of the gaseous reactants were as follows: C ₃ H ₆ 300 ml / min .; HCl 200 ml / min .; O ₂ 100 ml / min.

60

65

*) Catalyst I = CuCl _? - NaHSO ₄ - NH ₄ HSO ₄

(according to the invention).

Catalyst II = CuCl ₂ - KCl (comparative catalyst). Catalyst III = only CuCl ₂ (comparative catalyst).

Table III

Yield of reaction product, g / hr. 16.0
Composition of the reaction product

Isopropyl chloride,% 27.7

1,2-dichloropropane,% 38.0

Allyl chloride,%
Rest,%

30.1

4.2

Example 4

This example shows that the already higher activity of the catalyst according to the invention by itself The addition of thorium chloride, cerium chloride or lanthanum chloride can be increased even further, so that a high degree of conversion can be achieved at higher throughput speeds.

Table IV shows the relationship between throughput rate and degree of conversion for carrying out the oxychlorination at a molar ratio of NaHSO ₄ to NH ₁ HSO ₄ to CuCl ₂ to chloride of Th, Ce or La = 1: 1: 2: 0.2, a reaction temperature of 200 ⁰ C and a molar ratio of C ₂ H ₄ to HCl to O ₂ = 3: 2: 1.

Table IV

catalyst

NaHSO ₄ - NH ₄ HSO ₄ - CuCl ₂

NaHSO ₄ - NH ₄ HSO ₄ - CuCl ₂ + ThCl ₄
, NaHSO ₄ - NH ₄ HSO ₄ - CuCl ₂ + LaCl ₂

NaHSO ₄ - NH ₄ HSO ₄ - CuCl ₂ + CeCl ₃

Throughput speed 800 1000 400 600 77.6 41.5 99.7 90.8 98.0 98.0 99.5 99.0 98.0 97.5 99.5 99.0 95.0 91.2 99.3 98.5

1200

95.0
80.0

75.5

The throughput rate and the degree of conversion of the hydrogen chloride were based on the the following equations are determined:

Throughput speed =

[F (C ₂ H ₄ ) + F (HCl) + F (O ₂ )] [V] 1 / hr.

τι λλ λ un [2M (ADC) + M (VC) -I- M (AC)] .__ ".

Degree of conversion of HCl = —— ^{x 10 %}

LM (HCI) J.

Herein means

F (C ₂ H ₄ ) = feed rate of the C ₂ H ₄ ,

1 H.,

F (HCl) = feed rate of the HCl,
i / hour,

F (O ₂ ) = oxygen supply rate, 1 / hour,

V = catalyst volume, 1,

M (ADC) = amount of 1,2-dichloroethane produced, Moles / hour,

M (AC) = amount of ethyl chloride produced, Moles / hour,

M (VC) = amount of vinyl chloride produced, moles / hour,

M (HCl) = amount of hydrogen chloride introduced, mol / hour.

Claims (2)

Claims:, 0 1. Process for the catalytic oxychlorination of monoolefin hydrocarbons which are liquid or gaseous at room temperature at low temperature with hydrogen chloride and oxygen or an oxygen-containing gas, characterized in that the oxychlorination is carried out at 150 to 350 ⁰ C in the presence of a catalyst which is made of copper (II) chloride, one or more alkali metal bisulphates and ammonium bisulphate and a carrier containing the said compounds absorbed, the molar ratio of the total amount of bisulphates to copper (II) chloride being in the range from 1: 0.1 to 10. 2. The method according to claim 1, characterized in that a catalyst is used which also lanthanum chloride, cerium chloride or thorium chloride or mixtures of these compounds contains, the molar ratio of copper (II) chloride to the total amount of lanthanum chloride, Cerium chloride and thorium chloride ranges from 10: 0.1 to 1.0. 009 540/386