WO2006094746A1

WO2006094746A1 - Catalyst for acetoxylation of c2-c9-hydrocarbons

Info

Publication number: WO2006094746A1
Application number: PCT/EP2006/002041
Authority: WO
Inventors: Stephan Andreas Schunk; Christian Baltes
Original assignee: Hte Aktiengesellschaft
Priority date: 2005-03-07
Filing date: 2006-03-06
Publication date: 2006-09-14
Also published as: DE102005010379A1

Abstract

Catalyst containing a metal of the platinum group, a further metal or semimetal, an alkali metal or alkaline earth metal and/or their oxidized forms and also a magnesium-containing oxide, preferably Pd, K and Bi, or Pd, K, Bi and Pt being present, for the acetoxylation of a C2-C9-hydrocarbon such as olefins or alkyl aromatics, but in particular butadiene, in the gas phase in the presence of an oxygen-containing atmosphere and acetic acid.

Description

Catalyst for the acetoxylation of C ₂ -C hydrocarbons

The invention relates to a catalyst containing at least one metal from the platinum group, another metal or semimetal and an alkali or alkaline earth metal, wherein the metals and / or their oxidized forms are applied to a magnesium-containing support material. Preferably, Pd, K and Bi or Pd, K and Bi are used together with Pt. Further objects of the invention are a process for the preparation of the catalyst and the use of the catalyst for the acetoxylation of C ₂ -C ₉ -hydrocarbons in the gas phase, preferably of olefins or alkylaromatics, but especially of butadiene. Another object of the invention is the use of magnesium-containing oxides in the acetoxylation of C ₂ -C ₉ hydrocarbons.

Prior art summaries of the development of catalysts useful in the acetoxylation of olefins are disclosed in US 5,179,056 and US 6,399,813.

In particular, processes for the acetoxylation of ethylene in the gas phase are practiced industrially. The catalysts used here as a rule consist of the components K and Pd and one or more further elements which are applied to a suitable support material. DE 154 22 57 discloses the preparation of vinyl acetate in the gas phase with the aid of palladium-containing solid catalysts which, in addition to the palladium, may optionally contain one further metal component from the group copper, silver, gold, ruthenium, rhodium, osmium, iridium or platinum. The preparation of the catalysts via the deposition of the active component or the active components on an oxidic support, which is mixed with alkali metal salt solution in the further course of treatment.

GB 1 215 210 discloses a catalyst for the preparation of unsaturated esters, for example vinyl acetate, by a gas phase process. In this case, olefins and carboxylic acids are catalytically reacted in the presence of oxygen in high yields to the corresponding ester compounds. The preparation of the catalyst is based on an entry of palladium and platinum components on a support of inert material and the subsequent treatment of the loaded support material with alkali metal-containing or alkaline earth metal-containing compounds as activators, for example potassium acetate and sodium acetate.

US Pat. No. 5,342,987 discloses catalysts based on the active components palladium, gold and potassium which are suitable for the preparation of alkenylalkanoates. As advantageous for the catalytic effect of the catalysts, a particularly low sodium content of the catalysts used is given. It should be noted that the carrier should have a capability to exchange ions so that excess sodium species can be removed as completely as possible from the catalyst. The lowering of the sodium content is carried out by the treatment of the catalyst with salt solutions containing, for example, lithium, potassium, ammonium or magnesium ions. Suitable carriers appear to be conventional aluminosilicates and preferably conventional silicates which have a high BET surface area. Of particular interest is the acetoxylation of butadiene to 1,4-diacetoxybutene (1,4-DAB) and 1-acetoxybutadiene (1-ABD), since these acetoxylation products are important intermediates for the production of butanediol and tetrahydrofuran. Methods are known for the acetoxylation of butadiene in the liquid phase, which provide 1,4-DAB with high yield. For example, US Pat. No. 3,922,300 discloses the reaction of butadiene with acetic acid on Pd-containing catalysts under pressure in the liquid phase.

Of great economic importance are processes for the acetoxylation of butadiene in the gas phase, which lead to high yields of 1,4-DAB. No. 3,671,577 discloses a process in which catalysts consisting of palladium on activated carbon with promoters Li acetate, Na acetate, K acetate are used, with low conversions of up to 3% high selectivities reaching up to 90% of Actetoxylierungsprodukten become. US 3,872,163 discloses a similar gas phase process utilizing Pd as the active metal on various supports with different promoters such as Li, Na and K acetate. High selectivities of acetoxylation products are also achieved here with low conversions.

In view of the economic importance of acetoxylated products, the object was to provide further catalysts for acetoxylation reactions, with which high selectivities can be achieved with good yields of acetoxylation even at high conversions.

This object is achieved with a catalyst comprising a metal from the platinum group, another metal or semimetal, an alkali or alkaline earth metal and / or their oxidized forms and a magnesium-containing oxide.

For example, with such a catalyst in the acetoxylation of butadiene, a yield of 1-acetoxybutadiene in the range of 10% and above - A -

and a yield of diacetoxybutene in the range of about 5 to 7%, with conversions of butadiene of about 20 to 30% are possible (see also Examples 8 to 11 and 13 in Table 1, wherein the butadiene content in the carrier gas stream 0.5% is).

By the term "further metal" is meant an element of the transition elements. Semi-metals are boron, silicon, germanium, arsenic, antimony, tellurium, polonium, bismuth, selenium.

The term "oxidized forms" means that the elements can also be present in higher oxidation states than 0.

In one embodiment of the catalyst, the metal from the platinum group Pd.

In a further embodiment, the further metal is Pt.

In a further embodiment, the semimetal is Bi.

Another embodiment contains as alkali metal K.

In a particularly preferred embodiment, Pd, K and Bi are present.

In a further particularly preferred embodiment, Pd, K, Bi and Pt are present. Although the said elements or their oxidized forms in the catalyst may also be present as a solid material, ie without a carrier material, they are used together with the magnesium-containing oxide. The magnesium-containing oxide is used as a carrier oxide or is present in a carrier oxide.

The magnesium-containing oxide is preferably selected from the group of refractive oxides, for example consisting of SiO ₂ , Al ₂ O ₃ , TiO ₂ . Also known for catalytic purposes zeolites are well suited. Examples are zeolite Y, beta zeolite, ZSM-5, mordenite. Particularly noteworthy here are the ion-exchanged forms of zeolites, whereby magnesium-containing ion-exchanged forms are to be emphasized. It is also conceivable to use materials which have zeolite-like properties, for example mesoporous materials and phosphorus-containing aluminosilicates.

It is also possible to use mixtures of the abovementioned oxides.

In particular, all magnesium-containing oxides may be mentioned, in which the magnesium is present together with at least one elemental oxide selected from the group consisting of silicon, aluminum, titanium, zirconium, cerium and any desired mixture of these oxides.

Particularly noteworthy here are magnesium-containing silicates, aluminosilicates and aluminates.

The hydrotalcite should also be mentioned as a carrier material.

Preferably, the magnesium-containing oxide is a silicate, which is preferably present in crystalline form. When using steatite, a magnesium-containing silicate or layered silicate, in a carrier material or as a carrier material particularly good results are achieved.

But it is also possible to use other refractive oxides such as zirconium oxide or carbon-containing, metallic or organic polymers as support materials, such as PEEK, stainless steel, activated carbon.

The weight ratio of active components, ie the metal from the platinum group, the further metal or semimetal, the alkali or alkaline earth metal and / or their oxidized forms to the total weight of the catalyst is preferably in the range from 0.1: 25, preferably 0.5 : 10.

In the most preferred embodiment of the catalyst containing Pd, Pt, Bi and K, the molar ratio of Pd and Pt to Bi and K are each in the range of 10: 0.05, preferably 2.5: 0.5.

In the acetoxylation of butadiene, the highest yields for 1,4-DAB in the composition range Pd 5-45 mole%, Pt 25-75 mole%, Bi 10-70 mole%, and K 5-15 mole% can be obtained ,

The highest yields for 1-ABD can be obtained in the composition range Pd 30-70 mol%, Pt 5-40 mol%, Bi 10-50 mol% and K 5-15 mol%.

The highest yields of vinyl acetate can be obtained in the composition range Pd 10-20 mol%, Pt 60-85 mol%, Bi 10-20 mol% and K 5-15 mol%. Another object of the invention is also a process for the preparation of the catalyst, wherein the metal from the platinum group, the further metal or semimetal, the alkali or alkaline earth metal and / or their oxidized forms are deposited on the magnesium-containing oxide.

The deposition can be carried out by impregnation or precipitation in analogy to the known from the catalyst preparation process.

In this case, the magnesium-containing oxide can be impregnated with the components or these can be deposited or precipitated on the magnesium-containing oxide. The components can be applied together or by stepwise individual addition. It is possible to separate them from solution or from the gas phase.

In the preparation of the catalyst, for example, the particularly preferred compositions Pd, K and Bi or Pd, K ₅ Bi and Pt are used either in metallic form, but preferably in oxidized form.

For example, the chlorides, acetates, nitrates, organic compounds such as carbonyl compounds, amine complexes or alcoholates, oxides and hydroxides, nitrides can be used. These are also called precursor connections.

It is preferred here that at least one of the precursors used dissolves in one or more solvents. As solvents, water, alcohols, ethers, esters and other solvents can be used, which meet the requirements of solubility. Particularly preferred is water as a solvent. In specific embodiments, it is possible to add to the solvent regulators for regulating the pH or complexing agent or reducing or oxidizing agent. Such additives may be added at be used in subsequent preparation steps such as impregnations in different concentrations.

After impregnation, precipitation or separation of the components, a physical-chemical treatment step usually follows. Such steps may include, for example, annealing and / or calcination. Also, a treatment with reactive gases is possible. Suitable gases are, for example, H ₂ , H ₂ / CO.

Further steps are drying processes, which can be carried out thermally or by freeze-drying, the hydrothermal treatment, irradiation with light.

The described preparation methods and the physico-chemical treatment steps are known from the catalyst preparation.

Before using the catalyst, there is a further possibility of treatment with reactive gases in order to activate or regenerate the catalyst, whereby treatment at elevated temperature near the reaction temperature during the acetoxylation is preferred. The gases described above can be used.

Another object of the invention is also a process for the acetoxylation of C ₂ -C ₉ hydrocarbons using the catalyst. Preferably, this takes place in the gas phase in the presence of air and acetic acid.

Examples of suitable C ₂ -C ₉ hydrocarbons are olefins or alkylated aromatics, in particular alkylaromatics.

Examples of olefins are ethylene, propylene, butenes, butadiene, isoprene, 1-hexene, 1-octene, 1-dodecene, styrene. Examples of alkylated aromatics are toluene, xylenes.

The acetoxylation is carried out at a temperature of preferably 100 to 300 ⁰ C, in particular 150 to 250 ° C. The suitable temperature ranges are selected so that the reactants, namely acetic acid and C ₂ -C ₉ hydrocarbon are present in gaseous form. The acetoxylation takes place in an oxygen-containing atmosphere. Air may be used, but it is also possible to mix oxygen with an inert gas, such as nitrogen, in a desired ratio.

The implementation of the method is known from the above-described prior art. Preferably, the reaction is carried out continuously, for example in a fluidized bed.

The catalyst can be used particularly advantageously in the acetoxylation of butadiene, in particular in a process for the diacetoxylation. Here, in a first step, a feed stream comprising butadiene, acetic acid and oxygen generates 1-ABD over the catalyst according to the invention in high yield. In a second step, the feed gas stream containing 1-ABD and acetic acid is passed over a second catalyst and converted there to high yield to 1, 4-DAB. Preferably, the second step is not known with the catalysts from the first stage, but with acidic or amphoteric solids, such as zeolites, silica-aluminas, TiO ₂ , ZrO ₂ , acidic ion exchangers, ZnO, WO ₃ , WO ₃ on TiO ₂ and others refractive oxides, mixed oxides or polymeric materials.

A further subject of the invention is thus a process for the acetoxylation of butadiene comprising the step (i)

(i) acetoxylation of butadiene using the above-disclosed catalyst with acetic acid in the presence of an oxygen containing atmosphere in the gas phase, wherein the reaction can also be carried out in a fluidized bed.

This process is also characterized by further comprising the step (ii):

(ii) reacting the product obtained in step (i) in the gas phase with acetic acid using a catalyst.

The step (ii) is also characterized in that the catalyst is selected from the group of acidic or amphoteric solids, acidic ion exchangers, ZnO ₃ WO ₃ , WO ₃ on TiO ₂ , refractive oxides, mixed oxides.

Another object of the invention is the use of the catalyst in the above-disclosed acetoxylation of C ₂ -C ₉ hydrocarbons.

Furthermore, it has also been found that magnesium-containing oxides can favorably influence the acetoxylation of C ₂ -C ₉ -hydrocarbons in the gas phase.

Another object of the invention is thus the use of a magnesium-containing oxide for the acetoxylation of C ₂ -C ₉ hydrocarbons in the gas phase.

Preferably, the magnesium-containing oxide is selected from the group consisting of silica, alumina, aluminosilicate, titanium dioxide, zeolite or mixtures of these oxides. The zeolites described above can be used. Preferably, the magnesium-containing oxide is a silicate which is in crystalline form.

Preferably, the magnesium-containing oxide is steatite.

The magnesium-containing oxide can be used in a carrier material and / or as a carrier material in a catalyst.

Such carriers may be prepared by treating preferably SiO ₂ -containing materials with magnesium-containing precursors such as salts or gaseous magnesium compounds such as magnesium alkyls. Such magnesium-treated materials can be post-treated physically-chemically, for example by heat treatment, calcination or hydrothermal treatment. The preparation and after-treatment is known or can be done by known methods.

It is also possible to pretreat such compounds, for example steatite, mechanically, chemically or physically before applying the active components. In particular, those treatment methods are preferred in which the surface of the support material is roughened and hydrophilized. Such a treatment can be carried out, for example, by etching with acids or alkalis.

Active metals, ie metals or their compounds, or oxidized forms thereof, which promote the rate of acetoxylation in the acetoxylation of C ₂ -C ₉ -hydrocarbons as defined above in the gas phase with acetic acid, can be applied to this support material. The active metals used are preferably a metal from the platinum group, a further metal or semimetal, an alkali metal or alkaline earth metal and / or their oxidized forms, as defined above.

Pd, K and Bi or Pd, K, Bi and Pt and / or their oxidized forms are preferably present as active metals.

In the following, the production and testing of exemplary catalysts will be illustrated in exemplary embodiments. The fact that this is done on concrete examples with the indication of specific numerical values should under no circumstances be construed as limiting the statements made in the description and the claims.

Examples

An overview of the composition of the catalysts, which were prepared with different active components, amounts of active components and carrier oxides, is shown in Table 1.

example 1

The active composition of the composition Pd ₇₀ Bi _2O Ki ₀ on the carrier material steatite (2.1% total loading based on the elements) was prepared by impregnation of an aqueous solution of the following precursors:

1) paladium nitrate (Pd (NO ₃ ) ₂ x 2H ₂ O),

2) bismuth nitrate (Bi (NO ₃ ) ₃ · 5H ₂ O), 3) Potassium nitrate (KNO ₃ ).

The impregnated material was 1 hour at room temperature in air and then C (2 hours) and 400 ⁰ C (4 hours) under N ₂ calcined for 12 hours at 80 ° C and then dried at 200 ^0th

Examples 2 to 21 and Comparative Examples 1 to 3:

The catalysts of Examples 2 to 21 and Comparative Examples 1 to 3 were prepared analogously to Example 1, wherein the starting materials listed below were used for the preparation of the respective impregnating solutions: antimony acetate Sb (CH ₃ COO) ₃ , platinum nitrate Pt (NO ₃ ) ₂ , gold acid HAuCl ₄ , silver nitrate AgNO ₃ , copper nitrate Cu (NO ₃ ) ₂ x3H ₂ O _, tin oxalate Sn (C ₂ O ₄ ) ₂ .

The steatite with the chemical composition Mg ₃ [OH] ₂ ZSi ₄ O ₁₀ ] used for the investigations was obtained from Ceramtec, the alumina Al ₂ O ₃ from Sasol and the silicon dioxide SiO ₂ from Brace. The BET surface areas of steatite, alumina and silica were 1 m ² / g, 84 m ² / g and 31 m ² / g.

catalyst testing

The listed tests were carried out in a parallel test facility according to DE 100 12 847.5 and DE 103 36 086.7. For product analysis, a GC-MS was used. The catalyst materials were exposed to the reaction gas in a 192-fold test reactor (for execution of the test reactor see WO 01/68236) and the product gas was analyzed by GC-MS. The reactant gas mixtures used in the tests of the exemplary catalysts and the reaction products thus obtained are summarized in Tables 2 to 6 with respect to the respective olefinic component. All test reactions were performed at a GHSV of 2000 h- ¹ . The experiments shown in Tables 2 to 6 were carried out at a catalyst temperature of 180 ° C. In addition, comparative studies at 210 ° C were performed on the catalyst of Example 21, which are shown in Table 7.a and Table 7.b. Table 7.a shows the results obtained in the acetoxylation of 1,3-butadiene, and Table 7.b shows the results obtained for ethylene.

Table 1 Composition of the catalysts in the preparation of which the amount and type of active components was varied. In the catalysts of Examples 1 to 21 and Comparative Example 1, steatite was used as the carrier oxide. The catalysts in Comparative Example 2 were prepared using an alumina-containing and Comparative Example 3 using a silicon-containing carrier oxide.

the same catalyst composition as in Example 1; (a): the content of the element content refers to% by weight.

Table 2: Overview of the different educt gas mixtures which were tested on conversion of butadiene on the catalysts from Examples 1 to 20 and Comparative Examples 1 to 3, as well as the product gas compositions obtained thereby.

Table 3 Overview of the different educt gas mixtures which were tested in the conversion of ethylene over the catalysts from Examples 1 to 20 and the product gas compositions obtained thereby.

Table 4 Overview of the different reactant gas mixtures which were tested in the reaction of propylene on the catalysts from Examples 1 to 20, and the product gas compositions obtained thereby.

Table 5 Overview of the different reactant gas mixtures which were tested in the reaction of 1-butene on the catalysts from Examples 1 to 20, and the product gas compositions obtained thereby.

Table 6 Overview of the different educt gas mixtures which were tested in the reaction of 2-butene on the catalysts from Examples 1 to 20 and the product gas compositions obtained thereby.

Table 7.a Overview of the different reactant gas mixtures, which was tested in the reaction of butadiene on the catalyst from Example 21, and the product gas compositions obtained thereby. The investigations were carried out at catalyst temperatures of 180 ° C and 210 ° C.

Table 7.b Overview of the different educt gas mixtures that were tested in the conversion of ethylene on the catalyst from Examples 21, and the product gas compositions obtained thereby. The tests were carried out at a catalyst temperature of 210 ° C.

Claims

claims

1. Catalyst containing at least one metal from the platinum group, another metal or semimetal, an alkali or alkaline earth metal and / or their oxidized forms and a magnesium-containing oxide.

The catalyst of claim 1, wherein the metal is platinum group Pd.

3. A catalyst according to claim 1 or 2, wherein the further metal is Pt.

4. Catalyst according to one of the preceding claims, wherein the semimetal is Bi.

5. Catalyst according to one of the preceding claims, wherein the alkali metal is K.

6. Catalyst according to one of the preceding claims, wherein Pd, K and Bi or Pd, K, Bi and Pt are present.

7. Catalyst according to any one of the preceding claims, wherein the magnesium-containing oxide is selected from the group consisting of Siliziumdi- oxide, alumina, aluminosilicate, titanium dioxide, zeolite or mixtures of these oxides.

8. A catalyst according to claim 7, wherein the magnesium-containing oxide is a silicate which is in crystalline form.

9. A catalyst according to claim 8, wherein the carrier material is steatite.

A catalyst according to any one of the preceding claims, wherein the molar ratio of Pd and Pt to Bi and K are each in the range of 10: 0.05, preferably

2.5: 0.5.

11. Catalyst according to claim 1, wherein the weight ratio of metal from the platinum group, the further metal or halide metal, the alkali metal or alkaline earth metal and / or their oxidized forms to the total weight of the catalyst is in the range of 0.1: 25, preferably 0.5: 10.

12. A process for producing a catalyst according to any one of claims 1 to 11, wherein the elements and / or their oxidized forms are deposited on the magnesium-containing oxide.

13. The process according to claim 12, wherein impregnation or precipitation processes are used for the deposition.

14. A process for the acetoxylation of a C ₂ -C ₉ hydrocarbon using a catalyst according to any one of claims 1 to 11 or one Catalyst prepared according to claim 12 or 13, wherein the C ₂ -C ₉ hydrocarbon is reacted with acetic acid in the presence of an oxygen-containing atmosphere in the gaseous phase.

15. The method of claim 14, wherein the C ₂ -C ₉ hydrocarbon is an olefin or an alkylated aromatic.

16. The method of claim 14 or 15, wherein the reaction is carried out in a fluidized bed.

17. Process for the acetoxylation of butadiene comprising the step (i)

(i) a method as defined in any one of claims 14 to 16.

The method of claim 17, further comprising the step (ii):

19. The method of claim 18, wherein the catalyst is selected from the group acidic or amphoteric solids, acidic ion exchangers, ZnO, WO ₃ , WO ₃ on TiO ₂ , refractive oxides, mixed oxides.

20. Use of a catalyst according to any one of claims 1 to 11 or a catalyst prepared according to claim 12 or 13 in a method according to any one of claims 14 to 19.

21. Use of a magnesium-containing oxide for the acetoxylation of a C ₂ - Cp hydrocarbon in the gas phase.

22. Use according to claim 21, wherein the magnesium-containing oxide is selected from the group consisting of silicon dioxide, aluminum oxide, aluminum silicate, titanium dioxide, zeolite or mixtures of these oxides.

23. Use according to any one of claims 21 or 22, wherein the magnesium-containing oxide is a silicate which is in crystalline form.

24. Use according to claim 23, wherein the magnesium-containing oxide is steatite.

25. Use according to one of claims 21 to 24 in a carrier material and / or as a carrier material in a catalyst.

26. Use according to claim 25, wherein one or more active metals or their oxidized forms are applied to the carrier material.

27. Use according to claim 26, wherein as active metals a metal from the platinum group, another metal or semimetal, an alkali or alkaline earth metal and / or their oxidized forms are used.

28. Use according to claim 27, wherein Pd, K and Bi or Pd, K, Bi and Pt and / or their oxidized Forjnen present.