WO2001030730A1

WO2001030730A1 - Method for producing an alcohol from an alkene

Info

Publication number: WO2001030730A1
Application number: PCT/EP2000/010469
Authority: WO
Inventors: Ulrich Müller; Thomas Hill; Jochem Henkelmann; Arnd BÖTTCHER; Edgar Zeller
Original assignee: Basf Aktiengesellschaft
Priority date: 1999-10-25
Filing date: 2000-10-24
Publication date: 2001-05-03
Also published as: KR20020044173A; DE19951280A1; JP2003512444A; CO5231216A1; AU1144301A; CA2388881A1; MXPA02004070A; EP1226101A1; CN1399621A; AR026210A1

Abstract

The invention relates to a method for producing at least one alcohol by (i) hydrating at least one alkene to form the at least one alcohol, in the presence of water, by bringing said alkene(s) into contact with at least one catalyst. The invention is characterised in that the at least one catalyst is a zeolithic catalyst which has an MCM-22-, MCM-36-, MCM-49-, PSH-3- or ITQ-2- structure or a mixture of two or more of these structures.

Description

Process for producing an alcohol from an alkene

The present invention relates to a process for producing an alcohol starting from an alkene by hydrating the alkene by means of a zeolitic catalyst which has an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or has a mixture of two or more of these structures. The present invention also relates to an integrated process for the preparation of an alcohol, with unreacted starting material being recycled into the process.

It is known from the prior art that alkenes can be hydrated to alcohols using acidic catalysts. Examples of such catalysts are, for example, in Tanabe et al., Stud. Surf. Be. Catal. 51 (1989) pp. 247-254. Among other things, SiO-Al ₂ O _{3 is} disclosed there as a catalyst for the hydration of ethene to ethanol. The disadvantages of this catalyst, however, are low selectivity and therefore the formation of undesired by-products. Also in this publication, cation exchange zeolites of type A and Y are mentioned as catalysts for ethanol production, with type A, which comprises Mg, Ca, Cd, Zn etc., not allowing by-product formation, but type Y, on the other hand, enabling by-product formation.

Especially for the liquid phase hydration of cyclohexene to cyclohexanol, Ishida, Catalysis Surveys of Japan 1 (1997) pp. 241-246 zeolites of the types ZSM-5, ZSM-11, ZSM-12, ZSM-35, mordenite and Y are examined in more detail , where ZSM-5 and ZSM-1 1 are mentioned as those catalysts which have acceptable by-product formation. DE-A 34 41 072 discloses a process for the preparation of cyclic alcohols by catalytic hydration of cyclic olefins, a zeolite with a population ratio of the acid sites on the outer surface to the total number of acid sites of 0.07 or more being used as the catalyst. Examples include zeolites, and examples of the zeolites include mordenite, faujasite, clinoptilolite, zeolite L, ZSM-type zeolites, chabazite and erionite.

However, one disadvantage of these processes is that sufficient conversions can only be achieved with extremely fine-particle zeolites, which in turn are difficult to remove from the reaction mixture. A corresponding improvement is disclosed in EP-B 0 634 361. It describes a special agglomeration of pentasil zeolite particles which combines the advantages of high catalytic activity with simple separability. However, the process for the production of these agglomerates requires an apparatus which may be undesirable.

An object of the present invention was therefore to provide a method for producing an alcohol from an alkene which does not have the aforementioned disadvantages. Surprisingly, it has been found that alkenes can be hydrated by using a zeolite as heterogeneous catalyst which has an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture has two or more of these structures.

A MCM-22 structure zeolite is described, for example, in Kennedy et al., J. Am. Chem. Soc. 116 (1994) pp. 10000-10003 or in Leonowicz et al., Science 264 (1994), pp. 1910-1913.

The present invention therefore relates to a process for the preparation of at least one alcohol in which

(i) at least one alkene is hydrated in the presence of water by contacting it with at least one catalyst to which at least one alcohol is hydrated, characterized in that the at least one heterogeneous catalyst is a zeolitic catalyst which has an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of these structures having.

Zeolites are known to be crystalline aluminosilicates with ordered channel and cage structures that have micropores. The term “micropores” as used in the context of the present invention corresponds to the definition in Pure Appl. Chem. 57 (1985) pp. 603-619 and denotes pores with a pore diameter of less than 2 nm. The network of such zeolites is constructed from SiO and AlO ₄ tetrahedra, which are connected by common oxygen bridges An overview of the known structures can be found, for example, by WM Meier, DH Olson and Ch. Baerlocher in Atlas of Zeolite Structure Types, Elsevier, 4th edition, London 1996th

The zeolitic catalyst used according to the invention, which has an MCM-22, MCM-36, MCM-49, PSH-39 or ITQ-2 structure or a mixture of two or more of these structures, can be here by any suitable method be produced from the prior art. Among other things, it can be produced by a method which is described, for example, in US Pat. No. 4,954,325 or US Pat. No. 5,354,718.

In particular, the catalysts according to the invention have a Si: Al ratio which is preferably in the range from 10 to 1000, particularly preferably in the range from 10 to 100 and more preferably in the range from 10 to 50.

The specific surface area of the zeolite used according to the invention, determined according to Langmiur, is preferably in the range from 400 to 1000 m ² / g, more preferably in the range from 450 to 850 m ² / g and particularly preferably in the range from 500 to 750 m ² / g ,

The advantage that the type MCM-22 according to the invention offers, among other things, lies in the fact that zeolites of this type, owing to their crystallization form, are thin platelet agglomerates are present and accordingly have a high mass-specific activity.

It is also conceivable that the zeolite used according to the invention has further elements. Among other things, it preferably comprises at least one element of subgroups 1, 2 and 8. The present invention therefore also relates to a method as described above, which is characterized in that it contains at least one zeolitic at least one element from subgroup 1, 2 or 8 of the periodic table. The following elements should be mentioned in particular: Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt, Cu, Zn, Ag, Cd, Au, Hg.

The zeolite used according to the invention can likewise have the elements Ga and B.

As far as the use of the catalyst in the process according to the invention is concerned, all suitable geometries are generally possible. For example, the platelet agglomerates described above can be used per se. It is also possible to process the zeolite into a shaped body using a suitable method.

To produce these shaped bodies, the zeolite can, for example, be mixed with a binder, an organic viscosity-increasing substance and a liquid to increase the mass and compacted in a kneader or pan. The mass obtained can then also be shaped by means of an extruder or extruder. The moldings obtained are then dried and optionally calcined.

In order to produce molded articles which are also suitable for producing very reactive products, it is necessary to use chemically inert binders which prevent these products from reacting further. Suitable binders are a number of metal oxides. Examples include oxides of silicon, aluminum, titanium or zirconium. Silicon dioxide as a binder is disclosed, for example, in US 5,500,199 and US 4,859,785.

With such binders it may be necessary, for example, that the content of (earth) alkali metal ions is as low as possible, which is why it is necessary to use (earth) low-alkali metal or (earth) alkali metal-free binder sources.

Corresponding metal oxide sols can be used as starting materials for producing the metal oxide binders mentioned above. Accordingly, in the production of the (earth) low-alkali metal or (earth) alkali metal-free silicon dioxide binder mentioned, earth earth (low) alkali metal or (εrd) alkali metal-free silica sol is used as the binder source.

Such shaped bodies can be obtained, inter alia, by mixing the zeolite with metal oxide sol and / or metal oxide in one stage of the process, the metal oxide sol and the metal oxide each having a low content of (earth) alkali metal ions. Accordingly, the present invention also describes a method in which a molded body comprising at least one zeolite, which has an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of has two or more of these structures, and at least one metal oxide, wherein

(I) the at least one zeolite is mixed with at least one metal oxide sol which has a low content of alkali and alkaline earth metal ions and / or at least one metal oxide which has a low content of alkali and alkaline earth metal ions.

In a preferred embodiment of the process according to the invention, the metal oxide sol is produced by hydrolysis of at least one metal acid ester.

The metal acid esters due for hydrolysis can be cleaned before the hydrolysis. All suitable methods are conceivable. The metal acid esters are preferably subjected to a distillation before the hydrolysis. With regard to the hydrolysis of the metal acid ester, in principle all possible processes come into consideration. In the process according to the invention, however, the hydrolysis is preferably carried out in an aqueous medium.

The hydrolysis can be catalyzed by adding basic or acidic substances. Basic or acidic substances that can be removed without residue by calcining are preferred. In particular, substances are selected from the group consisting of ammonia, alkylamines, alkanolamines, arylamines and carboxylic acids. Nitric acid and hydrochloric acid. In particular Ammomak, alkylamines. Alkanolamines and carboxylic acids are used.

In the process according to the invention, preference is given to using, among other things, orthosilicic acid ester as the metal acid ester.

The hydrolysis of the metal acid esters takes place in the process according to the invention at temperatures from 20 to 100 ° C., preferably from 60 to 95 ° C. and at pH values from 4 to 10, preferably from 5 to 9, particularly preferably from 7 to 9.

In the process according to the invention, metal oxide sols, preferably inter alia silica sols, are obtained from the hydrolysis, which, among other things, contain (earth) alkali metal ions of less than 800 ppm, preferably less than 600 ppm, more preferably less than 400 ppm, more preferably less than 200 ppm , more preferably less than 100 ppm, particularly preferably less than 50 ppm, further particularly preferably less than 10 ppm, in particular less than 5 ppm.

The metal oxide content of the metal oxide sols produced according to the invention is generally up to 50% by weight, preferably 10 to 40% by weight.

The alcohol formed during the hydrolysis is generally distilled off in the process according to the invention. However, small amounts of alcohol can remain in the metal oxide sol as long as they do not show any disruptive effects in the further steps of the process according to the invention. Advantageous for the industrial use of the metal oxide sols produced according to the invention is their property of not showing any tendencies towards gel formation. Special precautionary measures to prevent gel formation are therefore superfluous. The shelf life of the metal oxide sols produced according to the invention is several weeks, which makes time coordination with further process steps unproblematic.

According to the invention, a mixture comprising at least the zeolite which has an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of these structures is used in the process, and at least one metal oxide, wherein a metal oxide sol is used as the metal oxide source, which is produced as described above.

In principle, there are no restrictions with regard to the method for producing the mixture. In the process according to the invention, however, preference is given to a suspension comprising at least the zeolite which has an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of these structures has, and metal oxide sol, sprayed.

There are no restrictions with regard to the zeolite content of the suspension, as long as the processability of the suspension during production and spraying is guaranteed. The weight ratio of zeolite to metal oxide of the metal oxide sol is preferably selected in the range from 10 to 0.1, particularly preferably in the range from 8 to 1.

The main components of the suspension are generally zeolite, metal oxide sol and water. The suspension may also contain traces of organic compounds. These can originate, for example, from the production of the zeolite. Likewise conceivable are alcohols which result from the hydrolysis of metal acid esters or substances which, as described above, are added to promote the hydrolysis of metal acid esters.

Depending on the moisture content of the mixture for further processing, drying can follow. All conceivable methods can be used. The mixture is preferably dried simultaneously with spraying in a spray drying process. The spray dryers are preferably operated with inert gases, particularly preferably with nitrogen or argon.

In a likewise preferred embodiment of the process according to the invention, the zeolite which has an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of these structures, in (I) mixed with at least one metal oxide which has a low content of alkali and alkaline earth metal ions.

In the event that the zeolite is mixed with two or more metal oxides, it is conceivable to first mix the zeolite with a metal oxide and to mix the resulting mixture with another metal oxide. If desired, this mixture obtained can in turn be mixed with another metal oxide. It is also possible to mix the zeolite with a mixture of two or more metal oxides.

The (earth) alkali metal content of this metal oxide or of the mixture of two or more metal oxides is generally less than 800 ppm, preferably less than 600 ppm, particularly preferably less than 500 ppm and particularly preferably less than 200 ppm.

Such metal oxides with a low content of alkali and alkaline earth metal ions are, for example, pyrogenic metal oxides, pyrogenic silica being mentioned as an example of such a pyrogenic metal oxide.

In the process according to the invention it is of course also possible to mix the mixture resulting from the mixing of the zeolite with the metal oxide with at least one metal oxide sol, which may have a low content of alkali and alkaline earth metal ions. With regard to the production of this mixture, as in the production of the mixture of zeolite and metal oxide sol, as described above, there are in principle no restrictions. However, a suspension comprising the mixture of the at least one zeolite and the at least one metal oxide and the at least one metal oxide sol is preferably sprayed. With regard to the zeolite content of this suspension, there are no restrictions as long as the processability of the suspension is guaranteed, as already described above. Furthermore, within the scope of the method according to the invention it is of course also possible to use a mixture consisting of the mixing of at least one zeolite which is an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 Structure or a mixture of two or more of these structures, with at least one metal oxide sol results, to be mixed with at least one metal oxide, which may have a low content of alkali and alkaline earth metal ions. The mixing with the at least one metal oxide can directly affect the preparation of the mixture from the at least one zeolite, which has an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or has a mixture of two or more of these structures, and connect the at least one metal oxide sol. As already described above, after the preparation of the mixture from the at least one zeolite which has an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of these structures, and the at least one metal oxide sol need to be dried, it is also possible to mix the metal oxide with the dried mixture after drying.

It is also possible within the scope of the method according to the invention to use the at least one zeolite which has an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of these Has structures to mix simultaneously with at least one metal oxide sol and at least one metal oxide.

The mixture obtained according to one of the embodiments of the invention described above is compressed in a further stage of the method according to the invention. Additional metal oxide can optionally be introduced into this compression or deformation layer, metal oxide sol produced as described above serving as the metal oxide source. This processing step can be carried out in all known apparatuses, but kneaders, mills or extruders are preferred. A pan is particularly preferably used for the industrial use of the method according to the invention.

According to an embodiment already described above, a mixture of the zeolite, which has an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a WO 01/30730. IQ - PCT7EP00 / 10469

Has mixture of two or more of these structures, and produced at least one metal oxide, this mixture is compressed and in the compression step additionally metal oxide sol, which has a low content of alkali and alkaline earth metal ions, is added, so in a preferred embodiment of the present invention 20 to 80 wt .-% zeolite, 10 to 60 wt .-% metal oxide and 5 to 30 wt .-% metal oxide sol. 40 to 70% by weight of zeolite, 15 to 30% by weight of metal oxide and 10 to 25% by weight of metal oxide sol are particularly preferably used. These percentages by weight are in each case based on the ultimately produced shaped body, as described below.

In a further embodiment of the method according to the invention, the at least one zeolite is mixed, which has an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of these Has structures with the at least one metal oxide, which may have a low content of alkali and alkaline earth metal ions, during the compression step. It is accordingly also possible in the compression step to use the at least one zeolite which has an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of these structures to mix the at least one metal oxide and additionally at least one metal oxide sol.

In this deformation step, one or more substances increasing the viscosity can also be added as pasting agents, which serve, inter alia, to increase the stability of the uncalcined molded article, as described below. All suitable substances known from the prior art can be used for this. In the process according to the invention, water and mixtures of water with one or more organic substances, provided these are miscible with water, are used as pasting agents. The pasting agent can be removed again when the molded body is subsequently calcined.

Organic, in particular hydrophilic organic polymers such as, for. B. cellulose, cellulose derivatives such as methyl cellulose, ethyl cellulose or hexyl cellulose, polyvinyl pyrolidone, ammonium (meth) acrylates, tylose or mixtures of two or more thereof. Methyl cellulose is particularly preferably used. As further additives, ammonia, amines or amine-like compounds such as. B. tetraalkylammonium compounds or amino alcoholates can be added. Such further additives are described in EP-A 0 389 041, EP-A 0 200 260 and WO 95/19222, which in this respect are incorporated in their entirety in the context of the present application by reference.

Instead of basic additives, it is also possible to use acidic additives. Organic acidic compounds which can be burned out by calcining after the shaping step are preferred. Carboxylic acids are particularly preferred.

The amount of these auxiliaries is preferably 1 to 10% by weight, particularly preferably 2 to 7% by weight, in each case based on the shaped body ultimately produced, as described below.

To influence properties of the molded body such. B. transport pore volume, transport pore diameter and transport pore distribution, other substances, preferably organic compounds, in particular organic polymers, can be added as further additives, which can also influence the deformability of the mass. Such additives include alginates, polyvinylpyrolidones, starch, cellulose, polyethers, polyesters, polyamides, polyamines, polyimines, polyalkenes, polystyrene, styrene copolymers, polyacrylates, polymethylacrylates, fatty acids such as stearic acid, high molecular weight polyalkylene glycols such as polyethylene glycol, polutylene glycol or polyglycol glycol or or mixtures of two or more thereof can be used. The total amount of these substances, based on the ultimately produced shaped body, as described below, is preferably 0.5 to 10% by weight, particularly preferably 1 to 6% by weight.

In a preferred embodiment, shaped bodies are produced in the process according to the invention which are essentially microporous, but can also have mesopores and / or macropores.

The order of addition of the additives described above to the mixture obtained according to one of the methods described above is not critical. It is both It is possible to first add further metal oxide via metal oxide sol, then the viscosity increasing and then the substances influencing the transport properties and / or the deformability of the compacted mass, as well as any other order.

Optionally, the mixture, which is usually still in powder form, can be homogenized in a kneader or extruder for 10 to 180 minutes. As a rule, work is carried out at temperatures in the range from approximately 10 ° C. to the boiling point of the pasting agent and normal pressure or slightly superatmospheric pressure. The mixture is kneaded until an extrudable mass has formed.

The mass to be deformed after compression in the process according to the invention has a metal oxide content of at least 10% by weight, preferably at least 15% by weight, particularly preferably at least 20% by weight, in particular at least 30% by weight on the total mass.

In principle, all conventional kneading and shaping devices or methods, such as are known in large number from the prior art and for the production of e.g. B. catalyst-shaped bodies are suitable, are used.

Methods are preferably used in which the deformation is carried out by extrusion in customary extruders, for example to form strands with a diameter of usually about 1 to about 10 mm, in particular about 1.5 to about 5 mm. Such extrusion devices are described, for example, in Ullmann's "Encyclopedia of Technical Chemistry", 4th edition, vol. 2 (1972), p. 295 ff. In addition to the use of an extruder, an extrusion press is also preferably used it is particularly preferred to work with extruders.

The extrudates are either strands or honeycomb bodies. The shape of the honeycomb is arbitrary. It can be round strands, hollow strands or star-shaped strands, for example. The diameter of the honeycomb is also arbitrary. About the outer shape as well as the Diameters usually determine the process requirements, which are specified by the process in which the molded body is to be used.

After the extrusion or extrusion has ended, the shaped bodies obtained are generally at 50 to 250 ° C., preferably 80 to 250 ° C. at pressures of generally 0.01 to 5 bar, preferably 0.05 to 1.5 bar in the course of approximately 1 dried up to 20 h.

The subsequent calcination is carried out at temperatures of 250 to 800 ° C, preferably 350 to 600 ° C, particularly preferably 400 to 500 ° C. The pressure range is chosen similar to that of drying. As a rule, calcination is carried out in an oxygen-containing atmosphere, the oxygen content being 0.1 to 90% by volume, preferably 0.2 to 22% by volume, particularly preferably 0.2 to 10% by volume.

The present invention thus also describes a method for producing molded bodies, as described above, in which

(I) the at least one zeolite, which has an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of these structures, with at least one metal oxide sol , which optionally has a low content of alkali and alkaline earth metal ions, and / or at least one metal oxide, which has a low content of alkali and alkaline earth metal ions, is mixed;

(II) the mixture of (I), optionally with the addition of metal oxide sol, is compressed;

(III) the mass from (II) is deformed into a shaped body; (IV) the molded body from (III) is dried and

(V) the dried molded article from (IV) is calcined.

A special embodiment of the invention consists in adding the metal oxide sol to the suspension as described above, drying the resulting suspension, preferably by spray drying, and calcining the resulting powder. The dried and calcined product can then be processed further in accordance with (III). Of course, the strands or extra data obtained can be made up. All methods of comminution are conceivable, for example by splitting or breaking the molded body, as well as other chemical treatments, such as described above. If comminution takes place, granulate or grit with a particle diameter of 0.1 to 5 mm, in particular 0.5 to 2 mm, is preferably produced.

This granulate or grit and also shaped bodies produced in another way contain practically no more fine-grained fractions than those with a minimum particle diameter of approximately 0.1 mm.

Also suitable as support material for the catalytic active component, the zeolite, which has an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of these structures all other suitable materials are also conceivable. For example, molded bodies or packs made of metal, ceramic or plastics, such as distillation packs, static mixers, mesh packs or resin beads, may be mentioned. On these materials the zeolite, which has an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of these structures, can be used according to all conceivable and suitable ones Methods are separated and immobilized. Such methods are disclosed, for example, in DE-C 42 16 846.5 and DE-A 196 07 577.7, which in this regard are incorporated in their entirety by reference into the context of the present application.

The alkene which is hydrated according to (i) can in principle originate from any suitable source, for example by any suitable method. Among other things, alkenes comprising 2 to 20 carbon atoms can be hydrated. It is also conceivable that the alkenes to be hydrated, in addition to at least one CC double bond, also have further functional groups which are optionally also accessible to hydration. It is also possible to use alkenes which are substituted in a suitable manner. Examples include the following alkenes: Ethene, propene, 1-butene, 2-butene, isobutene, butadiene, pentene, piperylene, hexene, hexadiene, heptene, octene, diisobutene, trimethylpentene, nonene, dodecene, tridecene, tetra- to eicosene, tri- and tetrapropene, polybutadienes, Polyisobutenes, isoprene, teφene, geraniol, linalool, linalyl acetate, methylene cyclopropane, cyclopentene, cyclohexene. Norbornene, cycloheptene, vinylcyclohexane, vinyloxirane, vinylcyclohexene, styrene, cyclooctene, cyclooctadiene, vinylnorbornene, indene, tetrahydroinden, methylstyrene, dicyclopentadiene, divinylbenzene, cyclododecene, cyclododecatriene, stilbene, diphenylhalidlyl haladlyl haladlyl haladlyl haladlyl haladlyl haladlyl haladlyl haladlyl haladlyl haladlyl haladlyl haladlyl halodlyl haladlhaladl halobluidyl haladlyl haladlyl haladlhaladl halodihalidlyl haladlyl halodihalidlyl haladl halodihalidlyl halodihalidlyl halodihalidyl halodihalidyl halodihalidyl halodiadlidyl halodi-halodi-oxychloride, diphenyl-aldehyde-halodi-oxychloride , Allyl alcohol, methallyl alcohol, butenols, butenediols, cyclopentenediols, pentenols, octadienols, tridecenols, unsaturated steroids, ethoxyethene, isoeugenol, anethole, unsaturated carboxylic acids such as, for. B. acrylic acid, methacrylic acid. Crotonic acid, maleic acid, vinyl acetic acid, unsaturated fatty acids, such as. As oleic acid, linoleic acid, palmitic acid, naturally occurring fats and oils.

The alkene itself is particularly preferably prepared from suitable starting materials in the process according to the invention, the alkene again being preferably produced starting from at least one starting material by hydrogenation of this starting material. Alkenes having 2 to 6 carbon atoms are preferably prepared from at least one starting material, it being possible for these alkenes to also have more than one C — C double bond. Therefore, the present invention also relates to a method as described above in which

(ii) the at least one alkene is prepared by hydrogenating at least one starting material.

It is conceivable, inter alia, that the alkene is prepared by selective hydrogenation of a compound having at least one CC triple bond. It is also possible, starting from an educt which has at least two CC double bonds, to prepare the alkene by selectively hydrogenating at least one CC double bond of the educt and at least one CC double bond being present in the hydrogenated educt. Of course, it is also conceivable to use starting materials which, for example, have at least one CC double bond and at least one further hydrogenatable functional group Have group to be hydrogenated selectively such that the hydrogenated starting material has at least one CC double bond.

Of course, in the process according to the invention, other functional grappas accessible to hydration besides C-C double bonds can also be hydrated. Among others, cyano groups, carboxylic acid ester groups or carboxamide groups are to be mentioned here. As already mentioned above, one or more of these functional groups can be present in the compound to be hydrated in addition to at least one C-C double bond.

Cyclic alkenes are particularly preferably hydrated in the process according to the invention. In principle, the cyclic alkenes used with preference can come from all conceivable sources, particularly preferably, as described above, can be prepared from all suitable starting materials by hydrogenation. In a very particularly preferred embodiment, the present invention relates to a process as described above, which is characterized in that the at least one alkene is cyclohexene and is prepared as a starting material by selective hydrogenation of benzene. The selective hydrogenation of benzene can be carried out, for example, according to a process as described in EP-A 0 220 525.

In a preferred embodiment, the hydrogenation of at least one suitable starting material and the hydration of the at least one alkene thus produced take place in a single stage. In the context of the present application, the term “a single stage” means that the at least one suitable starting material is hydrogenated in at least one suitable reactor and the alkene thus produced is hydrated in the same reactor. The present invention therefore also relates to a process as described above , which is characterized in that the preparation of the alkene according to (ii) and the hydration of the alkene according to (i) take place in a single step. Among other things, it is conceivable here that the at least one catalyst required for the hydrogenation and the at least one catalyst required for the hydration are used as different contacts. It is conceivable, inter alia, that the at least one hydrogenation catalyst in fixed bed and the at least one hydration catalyst in suspension mode or the at least one hydrogenation catalyst in suspension and the at least one hydration catalyst in fixed bed mode or the at least one hydrogenation catalyst and the at least one hydration catalyst in suspension or fixed bed operation can be used.

In a further embodiment, the process according to the invention is carried out as a reactive distillation. It is conceivable here, for example, to use at least one hydrogenation catalyst in, for example, suspension or fat bed mode, while at least one hydration catalyst is applied to the at least one distillation packing used to separate the organic from the aqueous phase, for example as a thin layer. It is of course also conceivable to apply both at least one hydrogenation catalyst and at least one hydration catalyst as a thin layer, for example, to the at least one distillation packing used for the separation. It is of course also conceivable here to use both hydrogenation and hydration catalysts in both suspension or solid mode and, at the same time, to charge the at least one distillation pack with at least one hydration catalyst or with at least one hydration catalyst and with at least one hydrogenation catalyst.

It is also conceivable, for example, to apply, for example to coat, inner walls of pipelines and / or reactors which are in contact with compounds to be hydrogenated and / or hydrated with the suitable catalysts.

In a preferred embodiment of the process according to the invention, the at least one hydrogenation catalyst and the at least one hydration catalyst are used as a single catalyst contact. Therefore, the present invention also relates to a _ _

A method as described above, characterized in that the zeolite having an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of these Has structures, is used as a carrier for at least one catalytic active component, which is used for the preparation of the alkene by hydrogenation of at least one starting material.

Here, it is conceivable, among other things, to use at least one hydrogenation-active component according to all suitable processes from the prior art on the zeolite, which is an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 Has structure or a mixture of two or more of these structures to apply. The resulting compound can then be used, for example, either as such in, inter alia, fixed bed or suspension procedures. It is also conceivable to apply the resulting compound, as already described above, for reactive distillation to the at least one distillation packing used to separate the organic from the aqueous phase. It is also conceivable to apply the resulting connection to the inner walls of, for example, the reactor or pipelines, for example in the form of a thin layer. With regard to the application of the hydrogenation-active component to the zeolite and the presence of the hydrogenation-active components on the zeolite, reference is made to DE-A 44 25 672, which in this respect is fully incorporated into the context of the present application.

It is also conceivable to produce a molded body in a manner as described in detail above, in addition to the zeolite, which is an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2- Has structure or a mixture of two or more of these structures, at least one hydrogenation-active component is incorporated. For example, zeolite and hydrogenation-active components can first be mixed and then deformed together with metal oxide sol and / or metal oxide by any suitable method. Among other things, it is possible to subject the mixture of zeolite and hydrogenation-active components together with metal oxide sol to at least one spray drying and then, if appropriate, deforming them with addition of pasting agent, for example kneaders or Koller can be used. It is also conceivable to produce a molded body, as described above, from at least zeolite and binder and to apply at least one hydrogenation-active component to the molded body. These shaped bodies according to the invention can then be used, for example, in the suspension or fixed bed mode.

These molded bodies can also be used, for example, to coat distillation packs for reactive distillation, or else the inside walls of the reactor and / or pipelines, as described above.

In a further preferred embodiment, the process according to the invention is carried out in such a way that hydrogenation and hydration are carried out in at least two different stages. The present invention therefore also relates to a process as described above, which is characterized in that the preparation of the alkene according to (i) and the hydration of the alkene according to (ii) is carried out in at least two different stages.

According to (ii), the at least one alkene can be prepared by all conceivable processes of the prior art, in particular by all conceivable processes from at least one suitable starting material. With regard to the at least one hydrogenation catalyst which is preferably used here, there are generally no restrictions. After the alkene has been prepared, it can be separated from the reaction mixture resulting from (ii) by any conceivable and suitable method and the hydration unit according to (i) can be fed. Among other things, it goes without saying that the hydrogenation itself is carried out in several stages.

In a further preferred embodiment of the process according to the invention, the reaction effluent which is formed in the hydrogenation according to (i) is fed to the hydration according to (i) without further working up. In a further particularly preferred embodiment, the process is carried out in such a way that unreacted starting material which is still present in the reaction discharge from (ii) is separated off from the reaction discharge from (i) after the at least one hydration stage (i) and is hydrogenated in accordance with ( ii) is fed again. Therefore, the present invention also relates to an integrated process for the preparation of at least one alcohol, wherein

(a) at least one alkene is prepared by hydrogenating at least one starting material,

(b) the reaction product from (a), comprising the at least one alkene and unreacted starting material, is transferred to a further step (c), (c) the at least one alkene is hydrated in the presence of water by contacting it with at least one heterogeneous catalyst .

(d) the unreacted starting material from (a) is separated from the reaction product from (c) and recycled to (a), which is characterized in that the at least one heterogeneous catalyst is a zeolitic catalyst which is an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of these structures.

Cyclic alkenes are particularly preferably prepared according to (a), with cyclohexene again being preferably produced by selective hydrogenation of benzene. The present invention therefore also relates to an integrated process, as described above, which is characterized in that the at least one alcohol is cyclohexanol, the at least one alkene cyclohexene and the at least one starting material which has not been reacted and recycled in (a) is benzene.

It is of course entirely conceivable within the scope of the present invention that, according to (ii), a plurality of alkenes are prepared simultaneously or in a number of stages, which can also have different processes. It is also conceivable for a plurality of alkenes to be prepared simultaneously or in a number of stages, which may also have different process procedures, by hydrogenating suitable starting materials. Furthermore, it is also conceivable that two or more alkenes can be used in (i), at least one of these alkenes being converted to one or, depending on the number of hydrogenatable CC double bonds, also a plurality of alcohols.

If the preparation of the at least one alkene to be hydrated and the hydration stage are carried out in separate stages, each stage can be carried out in the liquid phase, in the gas phase or in the supercritical phase, depending on the starting materials. It is also conceivable to carry out each individual stage either continuously or batchwise.

The hydration is preferably carried out in the liquid phase. In addition to the alkene or the alkene and unreacted starting material from (i) or very generally the reaction product from the preparation of the at least one alkene, in addition to water and the at least one catalyst, which is an MCM-22, MCM-36, MCM 49-, PSH-3 or ITQ-2 structure or a mixture of two or more of these structures, further suitable components are used in the at least one reactor which is used for hydration. For example, solvents suitable for hydration may be used in the at least one hydration reactor.

The hydration is preferably carried out at temperatures in the range from 50 to 250.degree. C. and with residence times of the reaction material in the reactor in the range from 0.5 to 8 hours.

Should the activity of the catalyst, which has an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of these structures, decrease in the course of the reaction, it is conceivable within the scope of the present invention to regenerate it. For example, it is possible to use a suitable solvent wash at elevated temperature or pressure, if necessary, or at elevated pressure and temperature.

In the liquid phase, detergents include oxidizing agents such as oxidizing acids or peroxide solutions such as hydrogen peroxide. In the supercritical phase, for example, carbon dioxide can also be used as a detergent. Likewise, the catalyst to be regenerated can be acted upon by increasing the temperature and / or increasing the pressure with a suitable gas mixture which is able to increase the activity of the deactivated catalyst. Preferred among others are oxygen-containing gases or also gases which can release oxygen under the selected regeneration conditions. Examples include nitrogen oxides, preferably N ₂ O.

All of the above-mentioned regenerations can take place in the installed state of the catalyst inside the reactor or else outside the reactor after removal of the catalyst. Of course, it is also possible to regenerate the catalyst several times. The present invention therefore also relates to a process or an integrated process as described above, which is characterized in that the at least one zeolitic catalyst is regenerated at least once and is used again in the process.

In principle, all processes known from the prior art for the regeneration of silicates comprising catalysts, in particular zeolite catalysts, can be used for the regeneration of the catalyst used according to the invention. In general, the used catalyst is treated at temperatures in the range from 20 to 700 ° C. in the presence or absence of oxygen or oxygen-providing substances in such a way that the activity of the regenerated catalyst is higher than that of the used catalyst.

In particular, the following processes should be mentioned: 1. A process for the regeneration of a spent (zeolite) catalyst, which involves heating the spent catalyst at a temperature of less than 400 ° C but higher than 150 ° C in the presence of molecular oxygen for a period sufficient to increase the Activity of the spent catalyst is included as described in EP-A 0 743 094;

2. A process for the regeneration of a spent (zeolite) catalyst, which involves heating the spent catalyst at a temperature of 150 ° C. to 700 ° C. in the presence of a gas stream which contains at most 5% by volume of molecular oxygen over a period of time that is sufficient to monitor the activity of the used

Improving catalyst comprises, as described in EP-A 0 790 075;

3. A process for the regeneration of (zeolite) catalysts, wherein the spent catalyst by heating at 400 to 500 ° C in the presence of an oxygen-containing gas or by washing with a solvent, preferably at a temperature which is 5 ° C to 150 ° C is higher than the temperature used during the reaction, as described in JP-A 3 11 45 36;

4. A process for regenerating a spent (zeolite) catalyst by calcining it at 550 ° C in air or by washing with solvents, restoring the activity of the catalyst as described in “Proc. 7 ^th Intern. Zeolite Conf. 1986 (Tokyo) '';

5. A process for the regeneration of a (zeolite) catalyst comprising the following steps (A) and (B):

(A) heating an at least partially deactivated catalyst to a temperature in the range from 250 ° C. to 600 ° C. in an atmosphere which contains less than 2% by volume of oxygen, and (B) loading the catalyst at a temperature in the range of 250 to 800 ° C, preferably 350 to 600 ° C, with a gas stream containing an oxygen-supplying substance or oxygen or a mixture of two or more thereof in the Has a range from 0.1 to 4% by volume,

the process also comprising the further stages (C) and (D),

(C) loading the catalyst at a temperature in the range of 250 to 800 ° C, preferably 350 to 600 ° C, with a gas stream containing an oxygen-supplying substance or oxygen or a mixture of two or more thereof in the range of more than 4 to 100% by volume,

(D) cooling the regenerated catalyst obtained in step (C) in an inert gas stream containing up to 20 vol .-% of a liquid vapor selected from the group consisting of water, an alcohol, an aldehyde, a

Ketone, an ether, an acid, an ester, a nitrile, a hydrocarbon and a mixture of two or more thereof,

may include. Details regarding this method can be found in DE-A 197 23 949.8.

It is also conceivable to wash the catalyst for regeneration with at least one hydrogen peroxide solution or with one or more oxidizing acids. Of course, the methods described above can also be combined with one another in a suitable manner.

Hydrogen-active components such as metals should be applied to the zeolitic catalyst, as is the case for a preferred embodiment of the present invention is described above, it is conceivable to detach them from the zeolite and reuse them for a new catalyst preparation

It is of course also conceivable in the context of the present invention that the regenerated catalyst is used in another process.

The invention will now be explained on the basis of the following examples.

Examples: Example 1: Preparation of MCM-22

8.3 g of sodium aluminate (43.6% Na ₂ O. 56.8% Al ₂ O ₃ ) and 5.3 g of NaOH cookies were dissolved in 200 g of deionized water in a stirring apparatus. A sulfuric acid solution consisting of 1 g H SO (98% by weight) in 50 g water was added to this solution. This solution was added with stirring to a suspension of 88 g of fumed silica (Aerosil 200) in 850 g of water. Finally, 48 g of hexamethyleneimine were added and the mixture was homogenized for 30 minutes. The mixture was reacted at 150 ° C. for 288 hours, filtered off and washed three times with 100 ml of water. The mixture was then dried at 120 ° C. and calcined at 500 ° C. in air for 5 hours. The product showed an X-ray diffractogram typical of MCM-22 and, after wet chemical analysis, was composed of 38.0% by weight of Si, 1.9% by weight of Al and 1.2% by weight of Na. The specific surface area determined according to Langmuir with N ₂ at 77 K was 639 m Ig. The material was converted into the ammonium form with a 0.1 N ammonium chloride solution, dried and calcined again at 500 ° C. in the course of 5 hours in air.

The product thus obtained still had a residual sodium content of 0.1% by weight.

Example 2: Use of MCM-22 for hydration In a 50 ml glass pressure autoclave, 3 g of the catalyst from Example 1 with 0.092 mol of benzene (reaction from the hydrogenation stage of the benzene to cyclohexene), 0.022 mol of cyclohexene and 0.2 mol of water were stirred for 5 hours at 120 ° C. implemented. The phase mixture obtained was homogenized after the reaction with the addition of dimethylformamide / methanol and analyzed by GC.

The yield of cyclohexanol on cyclohexene used was 9.2 mol%.

Example 3: Comparative example using β-zeolite for hydration

In a 50 ml glass pressure autoclave, 3 g of β-zeolite in the H form were reacted with 0.092 mol of benzene, 0.022 mol of cyclohexene and 0.2 mol of water with stirring for 5 hours at 120 ° C. The phase mixture obtained was homogenized after the reaction with the addition of dimethylformamide / methanol and analyzed by GC. The yield of cyclohexanol on cyclohexene used was only 7.5 mol%.

Claims

claims

1. A process for the preparation of at least one alcohol in which

(i) at least one alkene is hydrated to the at least one alcohol in the presence of water by contacting it with at least one catalyst, characterized in that the at least one catalyst is a zeolitic catalyst which is an MCM-22, MCM-36, MCM -49-, PSH-3- or ITQ-2-

Structure or a mixture of two or more of these structures.

2. The method according spoke 1, characterized in that the at least one zeolitic catalyst contains at least one element of the 1st, 2nd or 8th subgroup of the periodic table.

3. The method according to claim 1 or 2, in which

Method according to one of claims 1 to 3, characterized in that the at least one alkene is cyclohexene and is prepared as a starting material by selective hydrogenation of benzene.

5. The method according to any one of claims 1 to 4, characterized in that the preparation of the alkene according to (ii) and the hydration of the alkene according to (i) take place in a single step.

Process according to Claim 5, characterized in that the zeolitic catalyst which has an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of these structures , is used as a support for at least one catalytic active component which is used for the preparation of the alkene by hydrogenation of at least one starting material.

Method according to one of claims 1 to 4, characterized in that the preparation of the alkene according to (i) and the hydration of the alkene according to (ii) takes place in at least two different stages.

8. Integrated method for producing at least one alcohol, wherein

(d) the unreacted starting material from (a) is separated from the reaction product from (c) and recycled to (a), characterized in that the at least one heterogeneous catalyst is a zeolitic catalyst which is an MCM-22, MCM 36-, MCM-49-, PSH-3- or

ITQ-2 structure or a mixture of two or more of these structures.

9. Integrated method according to claim 8, characterized in that the at least one alcohol is cyclohexanol, the at least one alkene cyclohexene and the at least one in (a) unreacted and recycled starting material benzene.

10. The method according to any one of claims 1 to 9, characterized in that the at least one zeolitic catalyst is regenerated at least once and used again in the process.