DE2324441A1 - METHOD OF SYNTHESIS OF HYDROGENATION CATALYSTS - Google Patents

Description

The present invention relates to a new process for the preparation of heterogeneous catalysts with very large Activity that has numerous uses, especially in the hydrogenation of unsaturated compounds (especially of unsaturated hydrocarbons) and in the reforming reactions, whereby the term "reforming" of course on various reactions such as dehydrogenation, hydroisomerization, aromatization, dehydrocyclization various hydrocarbons, especially the paraffins and cycloparaffins.

It is known that the implementation of an organometallic Reducing agent with a salt of a transition metal is a very active homogeneous catalyst for hydrogenation in Solution of unsaturated hydrocarbons such as olefins, acetylenic or aromatic hydrocarbons results. Nevertheless, there has been no notable industrial development of the processes with soluble hydrogenation

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Catalysts come: The price of the catalyst is in the generally a considerable handicap compared to the heterogeneous Catalysts, but their activity is lower.

In an effort to keep the activity of the homogeneous catalysts using Combining the low cost per ton of converted products of classic heterogeneous catalysts are different Techniques have been applied. The guidelines have been set out in numerous patents. In this context are ... the French patents Hr.-1 367 202, 1,597,517, French additional patent 95,896 or US patent 3,536,632.

There are three broad categories:

Process no. 1 consists in the production of a homogeneous catalyst, which is either used according to variant 1A, to activate a classic heterogeneous catalyst, or according to variant 1B, where it is based on a mineral Carrier is applied. Method No. 2 impregnates a carrier with the reducing agent and then brings the metal salt with the carrier treated in this way for implementation. In method no. 3, the carrier is first impregnated with the metal salt, then a calcination at temperatures around 500 ° C and finally a reduction with the required Amount of reducing agent.

The catalysts prepared according to Process No. 3 are found in US Pat. No. 3,536,632 to be best proven. This is confirmed by the more recent French patent specification No. 2 072 586, in which the process No. 3 activities achieved have been improved.

On the other hand, it has been established - and that is the aim of this one Invention - that you can surpass all of the aforementioned techniques and use new hydrogenation catalysts extraordinarily high activity and stability properties

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can be prepared by impregnating suitable carrier materials, which are defined below, at temperatures above 150 ° C. by means of a homogeneous catalyst solution which is obtained by adding a salt of a transition metal with a mineral or organometallic reducing agent ^{at temperatures above 100 ° C. in a solvent} mixes. This idea was suggested in U.S. Patent No. 3,536,632 but was not maintained as the best practice. It should also be noted that this US patent contains the teaching to carry out the impregnation of the support by the homogeneous catalyst at a temperature between -60 and +150 ⁰ C and preferably between -10 and +100 ⁰ C, while it is according to the present In contrast, the invention is absolutely necessary ^{to work at temperatures of 150 0} C and above (see the following inventive examples and comparative examples 3 and 30).

The metal component of the reducing agent is an element of groups Ia, Ha, J ₁ ^ ₀ ^ _er im, of the periodic table of elements.

The conditions of the preparation of the catalyst solution and the impregnation with this solution play a very important role, if you want to get as active as possible. This activity practically corresponds to that of the homogeneous catalyst.

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The homogeneous catalyst is produced by reaction a metal compound with a mineral or organometallic reducing agent in the presence of a solvent compatible with the reducing agent.

As metals contained in the metal compound, can you can use those whose atomic numbers are between 22 and 29, 40 and 4Z, 72 and 79, or those with the atomic numbers 90 and 92. They can be in the form of salts or complex salts with

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Coordination sites of the Lewis base type, such as carbon oxide or ammonia, - can be used. This list is not limiting. The anions of the salts can be, for example, halides, alcoholates or carboxylates.

As reducing agents one can use the metals of group Ia or their derivatives, for example the derivatives obtained by reacting a metal of group Ia with an aromatic hydrocarbon such as naphthalene, the derivatives of saturated hydrocarbons such as butyllithium, the hydrides, the mixed hydrides with the metals Use group IHb such as boron or aluminum and their derivatives of substitution by alcohols such as the alcoxyalanates of sodium (Na AlH ₂ (OR) ₂ ) - preference is given to using the organometallic compounds soluble in the hydrocarbons or their etherified or esterified derivatives. So you can use the organolithium compounds or the organosodium compounds already mentioned, the organomagnesium compounds, the organozinc compounds or the organo aluminum compounds, in particular those of the formula Al R ^, where R is a hydrocarbon residue.

As examples of metal compounds and mineral or organometallic Reducing agents may be mentioned in the aforementioned French patents and the U.S. patents are listed.

The molar ratio of the transition metal compound to the reducing compound is usually 1:30 to 10: 1, preferably 1:10 to 1: 1.

The solvents used are saturated or unsaturated Hydrocarbons pure or in a mixture or the etherified or esterified solvents, the nitriles, and some Reducing agents can be used in the presence of alcohols. The choice of solvents depends on the solubility the metal salts and the reducing agents. 'If it happens, however, that one of the components of the catalyst

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is only sparingly soluble, the catalyst is after the reaction of the two components (metal salt and reducing agent) on each pall in solution.

The best activities are obtained by mixing the reducing agent with the metal salt under an inert atmosphere at temperatures between 100 and 250 ⁰ C.

The catalyst solution is preferably used for the impregnation at concentrations between 10 "and 10" gram atom Transition metal / liter in order to achieve a uniform impregnation on the carrier. It is preferable to work with solutions, which are diluted as much as possible. The preferred concentrations are between 10 "and 10 gram-atom metal / liter.

The selected amount of carrier is impregnated with the diluted solution either by dry or wet route, or by circulating the solution on top of a fixed bed in the reaction vessel arranged carrier. The latter technique is preferred, which has several advantages:

- It enables the synthesis of the catalyst in the unit, avoiding any handling of pyrophores,

- it can be done by continuously recycling the impregnation solvent use a minimum amount of solvent whatever the amount of metal that is placed on the support want.

In this pail there is also the circulation speed of great importance. Too low a speed leads to preferential absorption at the beginning of the carrier bed, and that would interfere with the application. The speeds depend essentially on the type of carrier. One receives in generally good impregnations at speeds between 5 and 500 liters of solution per kg of carrier and per hour.

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Another very important point is the impregnation temperature. It has been found that the impregnations carried out at ambient temperature have very little catalysts Activity. The temperatures are above 100 ° 0, but the best catalysts are obtained by between 150 and 25O ° C works.

Mineral or organic solids can be used as a carrier. The carriers which are particularly suitable in the context of the present invention are the oxides of metals such as magnesium, aluminum, titanium, zirconium, thorium or silicon, alone or in combination with one another or with oxides of other elements of the periodistshesa.i system. Before impregnation ea is important to subject the carrier to a treatment which results in a maximum removal of the water, as the calcination or any other treatment that reduces the percentage of water on the carrier. The content of hydroxyl groups OH is not decisive. The same applies to the surface area per gram of the carrier: CX aluminum oxides (surface area = 5 m / g) or

V -Aluminium oxides (surface area = 200 m / g) are impregnated and produced the same results.

After the impregnation, drying can be carried out under a stream of inert gas make.

The catalysts obtained in this way can be used in a fluidized bed, a liquid, a mobile or a fixed bed will.

They are suitable for the hydrogenation of the unsaturated hydrocarbons, namely the olefinic, diolefinic, acetylenic or aromatic, in the presence or absence of sulfur-containing derivatives. They enable selective hydrogenations. This type of hydrogenation is generally carried out at a temperature from -50 to 200 ° C, preferably between 0 and 150 ⁰ C, and under a pressure from 0.01 to 300 bar.

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The catalysts obtained are also suitable for reactions of the reforming process type, which are generally carried out at a temperature between 300 and 700 ^° C. and under a pressure of, for example, 1 to 20 bar. In certain cases a hydrogen atmosphere is advantageous.

The following examples serve to illustrate the present invention without, however, limiting it to them. the Examples 1, 3, 5 and 30 are given for comparison purposes and do not belong to the invention.

^{95 g of toluene are passed under argon and heated to 170 °} C. into a reaction vessel of the Grignard type made of stainless steel, provided with a device for feeding the catalyst under pressure catalyst solution obtained with 0.6 millimoles of nickel stearate at 160 ° C. in toluene. The pressure is adjusted to 30 bar by means of hydrogen and the mixture is stirred. After an hour, the hydrogen absorption stops. Analysis of the effluent shows that the toluene has been converted to methylcyclohexane with no detectable by-products.

Example_2

In the same device as that of Example 1, 10 g of potassium carbonate at 1100 ° C. are added. -Aluminium oxide, Man gives under argon 95 g of toluene are added, heated to 170 ° C. and then the catalyst solution which was prepared as in Example 1 is fed in and the same Has concentration. The mixture is stirred under argon for 3 to 5 minutes and a sample of 1 g of the solution is taken: the sample is clear and does not contain nickel. So the catalyst has been absorbed onto the alumina. The hydrogen pressure is then set to 30 bar and stir. After an hour, the absorption of hydrogen ceases and the analysis of the effluent shows only the presence of methylcyclohexane.

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This example shows that the speed on the Kataly Sator with carrier is the same as that of the homogeneous Kataly sators from which it comes.

In a device like that of Example 1, 10 g of CX are placed. Alumina, calcined "at 110o ⁰ C. This gives 95 g of toluene, and supplies at ambient temperature, a catalyst solution prepared as in Example 1 to give. The mixture is stirred under argon and takes a sample of 1 g The solution is clear. And does not contain nickel, This proves that the catalyst has been absorbed onto the support. Under argon, the mixture is heated rapidly to 170 ° C., a hydrogen pressure of 30 bar is applied and the mixture is stirred. The hydrogen is used up much more slowly, and analysis of a sample shows after one hour the presence of 10 ^ methylcyclohexane; the remainder is toluene.

This example shows that the catalyst is much less active when the impregnation is carried out at ambient temperature.

It is 10 g at 1100 ⁰ G treated Ot. -Aluminium oxide with 200 cw of a catalyst solution prepared as in Example 1 at 170 C and under an argon atmosphere. After a few minutes, the solvent is drawn off and the catalyst is dried. This is placed in a classic tubular reaction vessel under argon. The mixture is heated to 170 ^° C., a hydrogen pressure of 30 bar is applied, and while maintaining the Hg / hydrocarbon ratio = 8, the toluene is fed in at a throughput of 100 g per hour. The downstream end contains only methylcyclohexane.

Example ^ !?

For comparison, we have prepared a catalyst by applied to the same carrier (-CX alumina) in an aqueous medium, the nickel salt, calcined at 500 ⁰ C, with a

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Reduced triethylaluminum solution at 10O ⁰ C and treated under hydrogen at 300 ⁰ C for one hour. The activity was tested under the same conditions as in the previous example and although the catalyst contained 6 times more nickel, the effluent still contained 50% by weight of unconverted toluene.

Example ^

According to the preferred method of preparation is added in a tubular reaction vessel 10 g (X-alumina, which was previously calcined at 1000 ⁰ C. It is dried again for 2 hours at 170 ° C under an argon stream. Then, prepared according to the procedure described in Example 1 Method, a homogeneous catalyst which contains 0.6 millimoles of nickel stearate and 2.4 millimoles of triisobutylaluminum is produced ^{at 160 ° C. The volume of the catalyst solution is brought to 2 liters by dilution with heptane;} Hour on the support kept at 170 ° C. When the feed has ended, the traces of solvent are removed under a stream of hydrogen. The test carried out under the same conditions as in Example 4 shows that the outlet end contains only methylcyclohexane.

Example_7

Example 6 is repeated, but replacing the aluminum oxide with silicon dioxide and examining the activity of the catalyst using the test described in Example 4. The activity is practically the same as that with the alumina was achieved as a carrier.

The catalysts v / ground prepared by reacting at 170 ⁰ C 10 g

<X alumina impregnated with 200 cnr catalyst solution prepared by diluting the homogeneous catalyst prepared by reacting 0.6 millimoles metal salt with 2.4 millimoles of aluminum alkyl in 10 cnr decahydronaphthalene at 160 ⁰ C with heptane

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is obtained «The aluminum oxide is calcined ^{beforehand at 700 ° C.} The impregnation takes place outside the reaction vessel; the catalyst is dried under vacuum and placed under argon in the tubular reaction vessel used for the test.

The hydrogenation test of 'toluene or benzene is carried out at JO bar total pressure with a molar ratio V / hydrogen / reaction component = 8. It is found that in addition to the methylcyclohexane or the cyclohexane has not formed any other product. In the table below, the last column shows the composition of the effluent, determined by means of chromatography, indicated.

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For metal salt reduction reaction j No.

middle

Nicke is ear at

I ^ obalt stearate

Il Il Il

Iron stearate

Al et.

I Al Et ₃ AKiC ₄ H ₉ ).

Al Et-

Molybdenum-Al

(HI) -οetoat

Volframacetate

Ruthenium acetyl-; acetone

, Palladium acetylacetonate

; Platinum: acetyl acetonate;

Il /

Al et.

Toluene! 100

aunt

Reactant throughput in g / h

T ⁰ C

(Benzene toluene

benzene

Il

100 150 100

100 100 100 100

100 100

100 100

100 100

100 100

150

120 120 170

120 150 120 120

170 170

170 170

170 170

170 100

TAdd. of the! flowing off jCyclohexane or MeliiylcfycLohexan (Wt. ^)

100

100 100 100

70

100 90 12

50 100

100 60

80 100

100 100

With 10 g of a nickel-containing catalyst prepared according to Example 6, leads to "at 120 ⁰ C under a pressure of 30 bar a hydriding of 10 ppm sulfur (in the form τοη ThJPphen) by containing benzene, wherein the ratio hydrogen / hydrocarbon 8 and the throughput of benzene is 50 g per hour.After 8 hours of reaction, the hydrogenation of the benzene is complete

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in cyclohexane completely.

Example 25

With 10 g of a nickel-containing catalyst, prepared according to the method described in Example 6, a hydrogenation test of the isoprene is carried out at 25 ° C. under a pressure of 30 bar, the ratio of H 2 / hydrocarbon being 8. The isoprene is via Diluted 9 times its volume with heptene, and the liquid throughput is 120 g per hour, the hydrogenation in isopentane is complete.

Example__26

The previous example is repeated by introducing 20 ppm sulfur (in the form of thiophene) into the batch. The analysis of the effluent after 8 hours shows that the conversion of the isoprene is still complete, but that 20% by weight of olefin (Methyl-2-butene-2) remain.

Example_27

Example 25 is repeated, but 100 ppm of sulfur are added in the form of thiophane in the batch. After 5 hours the analysis of the outflow gives the following result: Isoprene < $ 0.3, methylbutenes $ 95, isopentane $ 4.7 (percentages by weight).

Example_28

Ih a reaction vessel a continuous manner are simultaneously tetralin, hydrogen and a catalyst solution obtained by mixing a Kobalthctoatlösung and a Triäthylaluminiumlösung in tetralin in a ratio ~ = 3 at 160 ⁰ C v / ill. The flow rates are such that the concentration of cobalt in the Reäktionsgefäß 1 millimole per liter and the molar ratio ^ / tetralin 1, WH (Volumendurehsatzgeschwindigkeit per hour) tetralin 2 and the temperature of 420 ⁰ C beträgt.'Die Naphthalinkonzentration of the effluent to be stabilized a few hours to $ 40, the rest is tetralin. The concentration of naphthalene does not increase significantly when one considers the concentration of cobalt

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elevated.

Example_29

A homogeneous catalyst solution is prepared similar to the previous one and containing 1 millimole of Co per liter. In addition, 10g -vorher at 800 ⁰ C calcined, powdered alumina "at 16O ° C under an argon atmosphere are dispersed in the tetralin. It is the catalyst solution to the alumina, and after a few minutes stirring, the solution is clear and contains no cobalt more. The on thus prepared on alumina catalyst is used in a continuous reaction vessel in • a fluidized bed the temperature is raised to 42O ⁰ C, WH of tetralin to 2 and the molar ratio hydrogen / tetralin maintained at 1;.. the Naphthalinkonzentration of the effluent is 78 wt # _f the rest is tetralin.

The same conditions are used as in Example 29, the only difference being that the aluminum oxide is at ambient temperature is impregnated. The resulting catalyst is far less active and under the same conditions gives only 15 ' G-ew. $ Naphthalene.

According to Example 29, it produces a catalyst solution by placing the decahydronaphthalene is used at a temperature of 160 ⁰ C as the solvent. The alumina is impregnated as before and the catalyst is used in the same reaction vessel. The reaction component is cyclohexane, which is fed in with WH = 1 and a molar ratio Hp / cyclohexane = 1. The outflow contains 40 wt .; " Benzene, the rest is exclusively cyclohexane.

Example_iel_32 ... · ■ · ■■: ■■ .. <

Proceed as in Example 31, but replace the cobalt with Nickel, which is supplied as nickel stearate, and reduced at

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a ratio Al / Ni = 3 * 5. The one under the same conditions An experiment carried out with cyclohexane gives an effluent which contains 80% by weight of benzene; the rest is cyclohexane.

The procedure is as in Example 31, but instead of being used as a carrier of the aluminum oxide washed with nitric acid and at 1100 ° C calcined silica. Under the same conditions, the downstream end contains 90% by weight of benzene; the rest is cyclohexane.

Baiapisl-24

The procedure is as in Example 31, but the cyclohexane as a reaction component is replaced by the cyclohexene. Under these conditions the outflow end is composed as follows (data in weight $): cyclohexane 9.5 $, cyclohexene 28.5 $, benzene 62 $. The dehydration reaction is associated with bismutation.

The procedure is as in Example 31, the reactant added to the reaction vessel being cumene. WH = 2, a molar ratio Hp / cumene = 2 and a temperature of 45O ⁰ C 15 percent is obtained in the effluent $ tf "methylstyrene and 10 wt $ originating from the cracking light hydrocarbons;.. The rest is cumene.

Following the technique described in Example 29 but using of 10 g of aluminum oxide in the form of extrudates of 1.5 mm 3 catalysts containing 2 wt. Molybdenum or tungsten or nickel are produced in diameter. After impregnation will be these catalysts are dried under vacuum and placed in a tubular reaction vessel under an inert atmosphere.

The dehydrogenation test of Heptäns is carried out under hydrogen pressure under the following conditions: P = 10 bar, T = 500 ⁰ C, WH liquid = 4, molar ratio _H? / HC = 4. Under these conditions one observes the formation of light products (C, -), but also of

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23244Λ1

Toluene. The following results are given in weight. $> In relation to the supplied heptane.

attempt No. catalyst C \ - + losses ^C 5 C. 6th ^iG 7 nC 7th To Iu 9 Mon 17th 5 * 1 1 , 5 11 63 1 , 4 10 W. 10 2.1 1 , 2 4th 80 , 5 2 , 2 11 Ni 20th 7th 3 , 0 2 66 , 9 1 ,1 example 39

Using the technique described in Example 29, a catalyst is prepared on powdered alumina containing 1 millimole of nickel per 10 g of alumina. After impregnation and drying, the catalyst is placed in a fluidized bed in a continuous reaction vessel under an inert atmosphere. The dehydrogenation test of the heptane is carried out under atmospheric pressure under the following conditions: WH liquid = 1, H ₂ / heptane = 4, T = 500 ⁰ C. It is observed the formation of some lighter C- ^ Cg-irodukten, isomers of heptane, C ^ / Cg olefins, but also of benzene and toluene. The obtained percentage (in weight) of toluene is 9.8 for a selectivity in relation to the converted heptane of 409ε.

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Claims (4)

Patents (i) Process for producing a catalyst, characterized in that that he a) a homogeneous catalyst solution is produced by mixing a salt clay metal with atomic numbers 22 to 29, 40 to 47, 72 to 79 or 90 to 92 with a metallic or organometallic reducing agent in a solvent at a ^{temperature above 100 ° C} , wherein the metal component is an element of group Ia, Ha, Hb or IHh, h) and a solid support at a temperature above 150 ° C impregnated with this solution. 2) The method of claim 1, wherein the carrier used is the oxide des aluminum, silicon, titanium, zirconium, magnesium or thorium. 3) Catalysts produced by means of the method according to one of Claims 1 and 2. 4) Use of the catalysts according to claim 3 for the hydrogenation of unsaturated compounds or in the reforming reactions. 30 98B0 / 1 099