MXPA02004070A

MXPA02004070A - Method for producing an alcohol from an alkene.

Info

Publication number: MXPA02004070A
Application number: MXPA02004070A
Authority: MX
Inventors: M Ller Ulrich
Original assignee: Basf Ag
Priority date: 1999-10-25
Filing date: 2000-10-24
Publication date: 2002-10-11
Also published as: JP2003512444A; KR20020044173A; CA2388881A1; CO5231216A1; WO2001030730A1; EP1226101A1; AR026210A1; CN1399621A; AU1144301A; DE19951280A1

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

METHOD FOR THE PRODUCTION OF ALCOHOL FROM AN ALKEN The present invention thus relates to a process for preparing an alcohol from an alkene by hydration of the alkene by means of a zeolitic catalyst having a structure MCM-22, MCM-36, MCM-49, PSH-3 or ITQ- 2 or a mixture of two or more of these structures. The present invention also relates to an integrated process for preparing an alcohol in which unreacted raw material is recycled to the process.

It is known from the prior art that alkenes can be hydrated to alcohols using acid catalysts. Examples of these catalysts are described, for example, in Tanabe et al., Stud. Surfing. Sci. Catal. 51 (1989), pp. In this, Si02-Al203, among others, is described as a catalyst for the hydration of ethene to ethanol. However, the low selectivity and thus the formation of undesirable byproducts are mentioned as disadvantages of this catalyst. Similarly this publication describes cation exchange zeolites of type A and Y as catalysts for the preparation of ethanol, wherein the catalysts type comprising Mg, Ca, Cd, Zn, ñ¡Á A ^^ A ^^ A * i and so does not allow the formation of by-products while, on the other hand, the type and enables products to be formed.

Specifically for the liquid phase hydration of cyclohexene to cyclohexanol, Ishida, Catalysis Surveys from Japan 1 (1997), p. 241-246, makes a thorough examination of the zeolites of the type ZSM-5, ZSM-11, ZSM-12, ZSM-35, mordenite and Y, mentioning the zeolites ZSM-5 and ZSM-11 as those catalysts showing formation of acceptable byproducts.

DE-A 34 41 072 describes a process for preparing cyclic alcohols by catalytic hydration of cyclic olefins, in which the catalyst used is a zeolite having a population ratio of the acid sites on its external surface to the total number of sites acids of 0.07 or more. Examples described are, among others, zeolites, and examples of the described zeolites are in turn mordenite, faujasite, clinoptilolite, zeolite L, zeolites of the type ZSM, chabazite and erionite.

However, a disadvantage of these processes is that satisfactory conversions are only achieved when zeolites of extremely fine particles are used which are difficult to remove from the reaction mixture. A relevant improvement is described in EP-B 634 361. This patent 0 describes a specific agglomeration of pentasil zeolite which combines the advantages of high catalytic activity with ease of separation. However, the production method of these agglomerates requires an expense in terms of the apparatus, which may be undesirable.

An object of the present invention is to provide a process for preparing an alcohol from an alkene which does not have the aforementioned disadvantages.

We have found that this goal is achieved by hydrating alkenes with a zeolite having a structure MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 or a mixture of two or more of these structures as a heterogeneous catalyst.

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

? T¿- ^ ay ^ (^ toja jjte to * M k Ek to mk The present invention therefore provides 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 form an alcohol or alcohols, wherein the catalyst or heterogeneous catalysts consists of a zeolitic catalyst with a structure MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 or a mixture of two or more of these structures.

The zeolites are, as is known, crystalline aluminosilicates having channel structures and ordered cages which have micropores. The term "micropores" when used for the purpose of the present invention corresponds to the definition of Puree Appl. Chem. 57 (1985), pp. 603-619, and refers to pores having a pore diameter of less than 2 nm.

The network of these zeolites is constituted by tetrahedral Si0 and A10 that are connected by linked oxygen bridges. A review of these structures can be found, for example, in W. M. Meier, D. H. Olson and Ch. Baerlocher and Atlas of Zeolite Structure Types, m * ti mmm É? ^ Elsevier, 4th edition, London 1996.

The zeolitic catalyst which is used according to the present invention having a structure MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 or a mixture of two or more of these structures in this case can be prepared by all convenient methods of the prior art. For example, it can be prepared by a method described, for example, in US 4,954,325 or US 5,354,718.

In particular, the catalysts according to the present invention have a Si: Al ratio 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 zeolites which are used according to the present invention, determined by the Langmuir method, is preferably in the range of 400 to 1000 m / g, more preferably in the range of 450 to 50 m / g particularly preferably in the range from 500 2 up to 750 m / g.

One of the advantages offered, for example, by the type MCM-22 used in accordance with the present invention is that zeolites of this type, due to their crystallization form, are obtained as thin platelet agglomerates and therefore have a high activity per unit mass.

It is also conceivable that the zeolites used according to the present invention contain other elements. For example, they preferably contain at least one element of the transition groups I, II and VIII. The present invention, therefore, also provides a process as already described in which the catalyst or zeolitic catalysts contain at least one element of transition group I, II or VIII of the Periodic Table. As elements of these transition groups, particular mention may be made of: Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt, Cu, Zn, Ag, Cd, Au, Hg.

The zeolite which is used according to the present invention can likewise contain the elements Ga and B.

With respect to the manner in which the catalyst is used in the process of the present invention, all suitable geometries are generally possible. Thus, for example, it is possible to use the agglomerates of platelets described above. It is also possible to process the zeolite by a convenient method to obtain a molded body.

To produce the molded bodies the zeolite can, for example, be mixed with a binder, a substance that increases the organic viscosity and a liquid to form a paste and can be compounded in a kneader or mill. The resulting mass can then also be formed by means of a piston extruder or propeller extruder. The molded bodies obtained subsequently are dried and, if appropriate, calcined.

To produce the molded bodies which are also convenient for preparing very reactive products, it is necessary to use chemically inert binders which prevent other reactions of these products.

Suitable binders are a series of metal oxides. Mention may be made, for example, of silicon, aluminum, titanium or zirconium oxides.

Silicon dioxide as a binder is described, for example, in US 5,500,199 and US 4,859,785. ililiitiÉiliim iüiiiiiniíi niii In these binders it may be necessary, for example, that the content of alkali metal or alkaline earth metal ions be very low, it being necessary to use binder sources which are low or 5 free of alkaline or alkaline earth metals.

As starting material for preparing the aforementioned metal oxide binders, it is possible to use corresponding metal oxide sols. In The preparation of, for example, the aforementioned silicon dioxide binder which is low or free of alkali metals or alkaline earth metals, silica sol which is low or free of alkali metals or alkaline earth metals, therefore, serve as sources 15 of the binder.

Molded bodies such as these can be obtained, inter alia, in one step of the process, by mixing the zeolite with the metal oxide and / or metal oxide sol, where the The sol of the metal oxide and the metal oxide in each case have a low content of alkali metal and alkaline earth metal ions. Accordingly, the present invention also describes a process in which a molded body containing at least one zeolite with a 25 structure MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 or a M IIUTI I Mlll lílli II II I III H mixture of two or more of these structures and at least one metal oxide, where: (I) the zeolite or zeolites are mixed with at least one metal oxide sol having a low content of alkali metal and alkaline earth metal ions and / or at least one metal oxide having a low ion content of alkali metals and alkaline earth metals.

In a preferred embodiment of the process of the present invention, the metal oxide sol is prepared by hydrolysis of at least one metal ester.

The metal esters that are used for hydrolysis can be purified before hydrolysis. All suitable methods are possible for this purpose. The metal esters are preferably subjected to distillation before hydrolysis.

With regard to the hydrolysis of the metal ester, in principle it is possible to use all suitable methods. However, in the process of the present invention the hydrolysis is preferably carried out in an aqueous medium.

The hydrolysis can be catalyzed by adding basic substances or acids. Preference is given to basic substances or acids that can be eliminated without leaving residues by calcination. In particular, use is made of substances selected from the group consisting of ammonia, alkylamines, alkanolamines, arylamines, carboxylic acids, nitric acid and hydrochloric acid. Particular preference is given to the use of ammonia, alkylamines, alkanolamines and carboxylic acids.

For the purpose of the process of the present invention, preferred metallic esters, inter alia, orthosilicic esters.

In the process of the present invention, the hydrolysis of the metal esters is carried out at temperatures from 20 to 100 ° C, preferably from 60 to 95 ° C, and at a pH from 4 to 10, preferably from 5 to 9, particularly preferably from 7 to 9.

In the process of the present invention, the hydrolysis produces sols of metal oxides, preferably silica sols having, for example, an alkaline earth metal and alkali metal ion content 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, more particularly preferably less than 10 ppm, particularly less than 5 ppm.

The metal oxide content of the metal oxide sol prepared according to the present invention 10 is generally up to 50% by weight, preferably from 10 to 40% by weight.

In the process of the present invention, the alcohol formed in the hydrolysis is generally distilled. However, small amounts of alcohol may remain in the metal oxide sol provided they do not interfere with the additional steps of the process of the present invention. 20 An advantage for the industrial use of suns from • Metal oxide prepared according to the present invention is the fact that they do not show tendency to gel formation. In this way, specific precautions to prevent the formation of 25 gel. The metal oxide sols prepared according to the present invention can be stored for a few weeks, timing problems not presenting problems for additional steps.

In the process of the present invention, a mixture containing the zeolite or zeolites with a structure MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 or a mixture of two or more of these structures and when minus one metal oxide are prepared using the metal oxide sol prepared as described above as a source of the metal oxide.

In principle there are no restrictions with respect to the method of preparation of the mixture. However, in the process of the present invention preference is given to the spraying of a suspension containing the zeolite or zeolites with a structure MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 or a mixture of two or more of these structures and a metal oxide sol.

With respect to the zeolite content of the suspension, there are no limitations as long as the processability of the suspension is ensured during preparation and spraying. The weight ratio of the zeolite to the metal oxide of the metal oxide sol is preferably chosen . *** ^ **** ^ - * -. ***** .. ^^ at ^ .. * »^, *, ^^ > "13 to be in the range from 10 to 0.1, particularly preferably in the range from 8 to 1.

The main constituents of the suspension are generally zeolite, metal oxide sol and water. The suspension may also contain residual traces of organic compounds. These can originate, for example, from the preparation of the zeolite. In the same way it is possible that alcohols formed in the hydrolysis of metal esters or substances that are added as already described to favor the hydrolysis of metal esters are present.

Depending on the moisture content that the mix will have for further processing, drying may continue. In this case, all possible methods can be used. The drying of the mixture is preferably carried out at the same time with the spray in a spray-drying process. Spray dryers are preferably operated using inert gases, particularly preferably nitrogen or argon.

In an embodiment of the same preferred mode of the process of the present invention, the zeolite having a structure MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 or a mixture of two or more of these structures is mixing in (I) with at least one metal oxide having a low content of alkali metal and alkaline earth metal ions.

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

The alkali metal and alkaline earth metal content of this metal oxide or 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 more particularly preferably less than 200 ppm. ppm.

Examples of metal oxides such as these which have a low content of alkali metal and alkaline earth metal ions are the pyrogenic metal oxides, for example pyrogenic silica. In the process of the present invention, it is of course also possible that the mixture resulting from the mixing of the zeolite with the metal oxide is mixed with at least one metal oxide sol having, if appropriate, a low content of metal ions. alkaline and alkaline earth metal. With regard to the preparation of this mixture, in principle there are no limitations, as in the • Preparation of the mixture of the zeolite and the metal oxide sol described above. However, preference is given to 10 the spray of a suspension containing the mixture of the zeolite or zeolites and the oxide or metal oxides and the sun or sols of metal oxide. There are no limitations with • regarding the content of the zeolite in this suspension, provided that, as already described, the 15 processability of the suspension.

Furthermore, in the process of the present invention it is naturally also possible that a mixture resulting from the mixing of at least one zeolite with a 20 structure MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 or a • mixing of two or more of these structures with at least one metal oxide sol mixed with at least one metal oxide having, if appropriate, a low content of alkali metal and metal ions 25 alkaline earth In this case, mixing with the oxide u The metal oxides can directly follow the preparation of the mixture of the zeolite or zeolites having a structure MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 or a mixture of two or more of these structures and the sun or metal oxide sols. If, as already described, drying is necessary after preparation of the mixture of the zeolite or zeolites with a structure MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 or a mixture of two or more of these structures and the sun or metal oxide sols, it is also possible to mix the metal oxide with the dried mixture after drying.

In the same way it is possible, in the process of the present invention to mix the zeolite or zeolites having a structure MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 or a mixture of two or more of these structures at the same time with at least one metal oxide sol and at least one metal oxide.

The mixture obtained according to one of the above described embodiments of the invention is composed in another step of the process of the present invention. In this composition or molding step, it is possible to introduce another metal oxide if desired, using a metal oxide sol prepared as already described as ^ * tg tíAmiAHA ma i k aFi metal oxide source. This processing step can be carried out in all known apparatuses for this purpose, but preference is given to kneading machines, mills or extruders. A mill is particularly preferred for the industrial application of the process of the present invention.

If, according to one of the above-described embodiments, first a mixture of the zeolite having the structure MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 or a mixture of two or more is prepared of these structures and at least one metal oxide, this mixture and a metal oxide sol having a low content of alkali metal and alkaline earth metal ions are added in the step of the composition, then, in a preferred embodiment of The present invention uses 20 to 80% by weight of zeolite, from 10 to 60% by weight of metal oxide and from 5 to 30% by weight of the metal oxide sol. Particular preference is given to the use from 40 to 70% by weight of zeolite, from 15 to 30% by weight of metal oxide and from 10 to 25% by weight of the metal oxide sol. These percentages are, in each case, based on the final molded body produced, as described below.

In another embodiment of the process of the present invention, the mixing of the zeolite or zeolites having a structure MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 or a mixture of two or more of these structures with the oxide or metal oxides which, if appropriate, have (n) a low content of alkali metal and alkaline earth metal ions are carried out during the passage of the composition. In the same way, it is possible to mix the zeolite or zeolites having a structure MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 or a mixture of two or more of these structures, the oxide or metal oxides and also at least one metal oxide sol in the composition step.

In this step of molding, it is also possible to add one or more substances that increase the viscosity as paste-forming agents that serve, among others, to increase the stability of the uncalcined molded body, as described below. For this purpose it is possible to use all convenient substances known from the prior art. In the process of the present invention, water or mixtures of water with one or more organic substances that are miscible with water are used as the pulp forming agent. The pulping agent can be removed rüMfcfr itiuMMfirr ^ -t - »- rt nnrtftrt? tt? again during the subsequent calcination of the molded body.

Preference is given to the use of organic polymers, in particular hydrophilic organic polymers such as cellulose, cellulose derivatives, for example, methylcellulose, ethylcellulose or hexylcellulose, polyvinylpyrrolidone, ammonium (meth) acrylates, Tylose or mixtures of two or more of these. Particular preference is given to the use of methylcellulose.

Other additives that can be added are ammonia, amines or amine-type compounds, for example, tetraalkylammonium compounds or amino alkoxides, other additives such as these are described in EP-A 0 389 041, EP-A 0 200 260 and WO 95/19222, the full description of which in this sense is hereby incorporated by reference in the present application.

In place of the basic additives, it is also possible to use acidic additives. Preference is given to acidic organic compounds that can be burned by calcination after the molding step. Particular preference is given to carboxylic acids.

The quantity of these auxiliaries is preferably from 1 to 10% by weight, particularly preferably from 2 to 7% by weight, in each case based on the final molded body produced, as described further 5 ahead.

To modify the properties of the molded body, for example, the volume of the transport pore, the diameter of the transport pore and the distribution of the 10 transport pore, it is possible to add other substances, preferably organic compounds, in particular organic polymers, as other additives that They may also influence the molding ability of the composition. Such additives include alginates, polyvinyl 15 pyrrolidones, starch, cellulose, polyethers, polyesters, polyamides, polyamines, polyimines, polyalkenes, polystyrene, styrene copolymers, polyacrylates, polymethacrylates, fatty acids such as stearic acid, polyalkylene glycols of high molecular weight as 20 polyethylene glycol, polypropylene glycol or polybutylene • glycol and mixtures of two or more of these. The total amount of these substances, based on the final molded body produced, as described below, is preferably from 0.5 to 10% by weight, particularly from Preferably from 1 to 6% by weight.

In a preferred embodiment, molded bodies that are mainly microporous but can further have mesopores and / or macropores are produced in the process of the present invention.

The order of addition of the additives described above to the mixture obtained according to the methods above # described is not important. It is possible to introduce another metal oxide first through the sun of 10 metal oxide, followed by the viscosity-increasing substances and then the substances that influence the transport properties and / or the • moldability of the composite composition or the use of any other order of addition. If desired, the generally still pulverulent mixture can be homogenized for 10 to 180 minutes in the kneader or extruder before the composition. This is usually done in an interval 20 temperature from about 10 ° C to the boiling point of the pulp forming agent and at atmospheric pressure or slightly super atmospheric pressure. The mixture is kneaded until a composition that can be extruded has been formed. The composition that has been composed and ready for molding has, in the process of the present invention, 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, based on the total composition.

In principle, the kneading and molding can be carried out using all the usual kneading and molding methods and methods which are known from the prior art and which are suitable for the production of, for example, molded catalyst bodies.

Preference is given to the use of methods in which the molding is effected by extrusion in customary extruders, for example, to obtain extrudates having a diameter usually from about 1 to about 10 mm, in particular from about 1.5 to about 5 mm. mm. Such extrusion apparatuses are described, for example, in "Ullmanns Enzyclopadie der Technischen Chemie" 4th edition, Volume 2 (1972), p. 95 ff. In addition to the use of a propeller extruder, preference is also given to the use of a plunger extruder. For industrial use for this purpose, particular preference is given to the propeller extruders.

The extrudates are rods or combs. The combs 5 can have any shape. These can be, for example, round extruded, extruded hollow or extruded in the form of a star. The combs can also have any diameter. The external shape and diameter are generally decided by the engineering requirements 10 of the process for the process in which the molded body is to be used.

After the extrusion is completed, the molded bodies obtained are generally dried at temperatures from 50 to 250 ° C, preferably from 80 to 250 ° C, at pressures generally from 0.1 to 5 bar, preferably from 0.05 to 1.5 bar, for approximately 1 to 20 hours. 20 The subsequent calcination is carried out at temperatures • from 250 to 800 ° C, preferably from 350 to 600 ° C, particularly preferably from 400 to 500 ° C. The pressure range is similar to that of drying. The calcination is usually carried out in one atmosphere 25 containing oxygen, with an oxygen content from or * *? ^^ 0.1 to 90% by volume, preferably from 0.2 to 22% by volume, particularly preferably from 0.2 to 10% by volume.

The present invention thus also describes a process for producing molded bodies as already described, in which: (I) the zeolite or zeolites having a structure MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 or a mixture of two or more of these structures is mixed with at least one metal oxide sol having, if appropriate, a low content of alkali metal and alkaline earth metal ions and / or at least one metal oxide having a low content of alkali metal and alkaline earth metal ions; (II) the mixture of (I), with or without the addition of the metal oxide sol, is composed; (III) the composition of (II) is molded to obtain a molded body; (IV) the molded body of (III) is dried and 'mi? i? teá a * ^^ (V) the dried molded body of (IV) is calcined.

A specific embodiment of the invention consists in adding the metal oxide sol to the suspension described above, drying the resulting suspension, preferably spray drying, and calcining the resulting powder. The dried and calcined product can then be processed as described in (III).

Of course, the extrudates can become a finished form. All crushing methods are possible in this case, for example, by grinding or breaking the molded bodies; Other chemical treatments, as described in the above are also possible. If grinding is carried out, granules or pieces having a particle diameter from 0.1 to 5 mm, in particular from 0.5 to 2 mm, are preferably produced.

These granules or pieces and also the molded bodies produced in another way contain almost no material having a particle diameter of less than about 0.1 mm.

As the support material for the catalytically active component, namely, the zeolite having a structure MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 or a mixture of two or more of these structures, it is also possible to use all other suitable materials. Examples that may be mentioned are molded bodies or packaging made of metal, ceramic or plastics, for example packaging for distillation, static mixers, mesh packaging or resin beads. The zeolite having a structure MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 or a mixture of two or more of these structures can be deposited and immobilized in these materials by all possible and convenient methods . Such methods are described, for example, in DE-C 42 16 846.5 and DE-A 196 07 577.7, the full description of which on this subject is hereby incorporated by reference in the present application.

The alkene that is hydrated as described in (i) in principle can arise from any source, for example it can be prepared by any convenient process. It is possible to hydrate, among others, alkenes having from 2 to 20 carbon atoms. In the same way it is possible that the alkenes are hydrated to have not only at least one double C-C bond, but also other functional groups that can also undergo hydration. In addition, it is possible to use alkenes that are substituted in a convenient way. Examples of suitable alkenes are: ethene, propene, 1-butene, 2-butene, isobutene, butadiene, pentenes, piperylene, hexenes, hexadienes, heptenes, octenes, diisobutene, trimethylpentene, nonenenes, dodecene, tridecene, tetradecenes, eicosenos, 10 tripropene and tetrapropene, polybutadienes, polyisobutenes, isoprene, terpenes, geraniol, linalool, linalyl acetate, methylenecyclopropane, cyclopentene,? cyclohexene, norbornene, cycloheptene, vinylcyclohexane, vinyloxirane, vinyl cyclohexene, styrene, cyclooctene, 15 cyclooctadiene, vinylnorbornene, indene, tetrahydroindene, methylstyrene, dicyclopentadiene, divinylbenzene, cyclododecene, cyclododecatriene, stilbene, diphenylbutadiene, vitamin A, beta carotene, vinylidene fluoride, allyl halides, 20 crotonyl, methallyl chloride, dichlorobutene, allyl alcohol, metal alcohol, buteneols, butenediols, cyclopentendiols, pentenoles, octadienols, tridecenols, unsaturated spheroids, ethoxyethene, isoeugenol, anethole, unsaturated carboxylic acids as 25 acrylic acid, methacrylic acid, crotonic acid, acid ? *? A * U * * ^ »*** - ^ ** kt ^ * ^ * ^ * ^ *. ^ - ^ i ^ ü ^ i maleic, vinylacetic acid, unsaturated fatty acids such as oleic acid, linoleic acid, palmitic acid, fats and natural oils.

Preference is given to the preparation of the alkene itself in the process of the present invention from the suitable raw materials, the alkene being preferably prepared from at least one starting material by hydrogenation of this starting material. Preference is given to the preparation of the alkenes having from 2 to 6 carbon atoms from at least one raw material, it also being possible for these alkenes to have more than one C-C double bond. The present invention, therefore, also provides a process as already described, in which: [ii) the alkene or alkenes are prepared by hydrogenation of at least one starting material.

It is possible, among others, that the alkene be prepared by selective hydrogenation of a compound having at least one triple C-C bond. It is likewise possible, starting from a raw material having at least two CC double bonds, to prepare the alkene by selectively hydrogenating at least one CC double bond of the raw material and leaving at least one CC double bond in the hydrogenated raw material . Of course, it is also possible that the raw materials have, for example, at least one CC double bond and at least 5 other functional groups capable of hydrogenation to be selectively hydrogenated in such a way that the hydrogenated raw material has at least two CC bonds. .

In the process of the present invention, of course, other functional groups capable of hydration different from the C-C double bonds can also be hydrated. Examples that may be mentioned are cyano groups, carboxylic ester groups or carboxamide groups.

As already mentioned, one or more of these functional groups may be present in the compound to be hydrated in addition to at least one C-C double bond.

In the process of the present invention, particular preference is given to the hydration of cyclic alkenes. In principle, the cyclic alkenes preferably used can arise from all possible sources; these particularly preferably, 25 as already described, they are prepared from all the JjfiaJÉlia ^^^ convenient raw materials by hydrogenation. In a very particularly preferred embodiment, the present invention offers a process as already described, wherein the alkene or the alkenes is (are) cycloalkene (s) and is prepared by selective hydrogenation of benzene as a raw material. The selective hydrogenation of benzene can, for example, be carried out by a process described in EP-A 0 220 525.

In a preferred embodiment, the hydrogenation of at least one suitable raw material and the hydration of the alkene or the alkenes prepared in this way are carried out in a single step. The term "one step" means, for the purpose of the present application, that the suitable raw material or raw materials are hydrogenated in at least one convenient reactor and the alkene prepared in this way is hydrated in the same reactor. The present invention, therefore, also provides a process as already described in which the preparation of the alkene as described in (ii) and the hydration of the alkene as described in (i) are carried out in a single step.

It is possible that, for example, the catalyst or the catalysts necessary for the hydrogenation and the catalyst or catalysts necessary for hydration are used in different ways. In this case, it is possible that, for example, the catalyst or catalysts for hydrogenation are used as a fixed bed and the catalyst or catalysts for hydration are used in suspension or that the catalyst or catalysts for the hydrogenation is used in suspension and the catalyst or hydration catalysts are used as a fixed bed; or the catalyst or catalysts for the hydrogenation and the catalyst or catalysts for hydration are used in suspension or as a fixed bed.

In another embodiment, the process of the present invention is carried out as a reactive distillation. In this case, it is possible, for example, to use at least one catalyst for hydrogenation in, for example, a suspension or a fixed bed, while at least one catalyst for hydrogenation is applied, for example, as a thin layer to the gaskets. distillation used to separate the organic phase from the aqueous phase. Likewise, it is certainly possible that at least one catalyst for hydrogenation and at least one catalyst for hydration is applied as, for example, a thin layer to the packaging or distillation packages used for the separation. Of course it is also possible to use the catalysts for hydrogenation and for hydration in suspension or as a fixed bed and at the same time load the packaging or packages of the distillation used with at least one catalyst for hydration or at least one catalyst for hydration and at least a catalyst for hydrogenation. 10 In the same way it is possible that, for example, the inner walls of the pipes and / or the reactor that are • in contact with the compounds that are going to be hydrogenated and / or to be hydrated are charged, for example, 15 coated, with the appiate catalyst.

In a preferred embodiment, of the process of the present invention, the catalyst or catalysts for the hydrogenation and the catalyst or catalysts for the 20 hydration are used as a single catalyst system.

• Thus, the present invention also provides a process as already described in which the zeolite having a structure MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 or a mixture of two or more of these structures, 25 used as support for at least one compound t * mta Mi * ¡i kw? mmt á catalytically active that is used to prepare the alkene by hydrogenation of at least one raw material.

In this case it is possible, for example, to apply at least one active component for the hydrogenation by any convenient method of the prior art to the zeolite having a structure MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 or a mixture of two or more of these structures. The resulting compound can then, for example, be used as such in a fixed bed or in suspension. In the same way it is possible to apply the resulting compound, as already described, to the packaging or distillation packages used to separate the organic phase from the aqueous phase in the reactive distillation. In the same way it is possible to apply the resulting compound to the inner walls of, for example, the reactor or the tubes, for example, in the form of a thin layer. With respect to the application of the active component for the hydrogenation to the zeolite and the presence of the active component for the hydrogenation on the zeolite, reference can be made to DE-A 44 25 672, the full description of which on this subject is incorporated hereby by way of reference in the present application.

HYDROLOGYHYME In the same way it is possible to produce a molded body in a manner described in detail in the foregoing, in which case at least one active compound for hydrogenation is incorporated in addition to the zeolite having a structure MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 or a mixture of two or more of these structures. Thus, for example, the zeolite and the active component for the hydrogenation can first be mixed and then molded together with the metal oxide sol and / or 10 metal oxide by any of the convenient methods. It is possible, for example, to subject the mixture of the zeolite and the active component to the ^ * hydrogenation together with the metal oxide sol to at least one step of spray drying and then, with or Without the addition of paste-forming agents, mold the spray-dried product with kneaders or mills, for example, that can be used for molding. It is also possible to produce a molded body as already described from at least the zeolite and the 20 binder and apply at least one active component for hydrogenation to the molded body. These molded bodies can then be used, for example, in suspension or as a fixed bed in the process of the present invention. 25 A At A ^ & These molded bodies can also be used, for example, as coatings on packages for distillation for reactive distillation or on the inner walls of the reactor and / or the pipeline, as already described.

In another preferred embodiment, the process of the present invention is carried out by carrying out the hydrogenation and hydration in at least two different steps. The present invention, therefore, also offers a process as already described in which the preparation of the alkene as described in (i) and the hydration of the alkene as described in (ii) are carried out in at least two different steps.

The alkene or alkenes can be prepared as described in (ii) using all possible processes of the prior art, in particular by hydrogenation of at least one suitable starting material using any possible process. In general there are no restrictions with respect to the catalyst or catalysts for hydrogenation preferably used herein. After the preparation of the alkene, this can be separated by all possible and convenient methods from the resulting reaction mixture t **? ** mil * mmm m! from (ii) and move to hydration as described in (i). It goes without saying that hydration, in principle, can be carried out in a plurality of stages.

In another preferred embodiment of the process of the present invention, the reaction mixture formed in the hydrogenation described in (i) passes without further treatment to hydration as described in (i).

In another particularly preferred embodiment of the process, the unreacted raw material still present in the reaction product of (ii), after the hydration step or steps (i), is separated from the reaction product of (i) and recycled to hydrogenation as described in (ii). Therefore, the present invention also provides an integrated process for preparing at least one alcohol, in which: (a) at least one alkene is prepared by hydrogenation of at least one raw material (b) the reaction product of (a) which comprises the alkene or alkenes and the unreacted raw material passes to another step (c) A ^ A? AJ ^ ^^^, ^. (c) the alkene or alkenes are hydrated in the presence of water by contacting it with at least one heterogeneous catalyst, and (d) the unreacted starting material of (a) is separated from the reaction product from (c) and recycled to (a), wherein the catalyst or the heterogeneous catalysts consist of a zeolitic catalyst having a structure MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 or a mixture of two or more of these structures.

In step (a), particular preference is given to the preparation of the cyclic alkenes, especially cyclohexene by selective hydrogenation of benzene. Therefore, the present invention also proposes an integrated process as described above in which the alcohol is cyclohexanol, the alkene is cyclohexene and the unreacted starting material that is recycled to (a) is benzene.

In the process of the present invention, of course it is generally possible that a plurality of alkenes is prepared in (i) at the same time or in a plurality of a ^ **** M * m steps that can also be done in different ways. In the same way, it is possible for a plurality of alkenes to be prepared simultaneously or in a plurality of steps, which can also be carried out in different ways, by hydrogenating suitable raw materials.

It is also possible to use two or more alkenes in (i), wherein at least one of these alkenes is converted to an alcohol or, depending on the number of C-C double bonds capable of hydrogenation, a plurality of alcohols.

If the preparation of alkene or alkenes which are to be hydrated and hydrogenation itself made in separate steps, each step can ef ctuarse, depending on the starting materials, liquid phase, gas phase or super critical phase. In the same way it is possible that each step is carried out continuously or in batches.

The hydration is preferably carried out in the liquid phase. In addition to the alkene or alkene and the unreacted raw material of (i) or very generally the reaction mixture from the preparation of the alkene or the alkenes, water and the catalyst or catalysts that kd ^^^^ kA ^^^ É ^ have a structure MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 or a mixture of two or more of these structures, other convenient components can be fed to the reactor or the reactors that are used for hydration. For example, suitable solvents for hydration can be fed into the reactor or reactors for hydration.

The hydration is preferably carried out at a temperature of from 50 to 250 ° C and with residence times of the reaction mixture in the reactor in the range from 0.5 to 8 hours.

If the activity of the catalyst having a structure MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 or a mixture of two or more of these structures decreases during the course of the reaction, the present invention proposes that it be regenerated if desired. Thus, for example, it is possible to wash it with a suitable solvent, if appropriate, at elevated temperature or super atmospheric pressure or at super atmospheric pressure and elevated temperature.

In a liquid phase reaction, the possible washing media are, among others, oxidizing agents £ *** & ^ j¿¿ *. as oxidizing acids or peroxide solutions, for example hydrogen peroxide. In the super critical phase it is also possible to use, for example, carbon dioxide as a washing medium. Similarly, the The catalyst to be regenerated can be treated at increased temperature and / or increased pressure with JAL a suitable gas mixture can increase the activity of the deactivated catalyst. In this case, preference is given to the use of, for example, gases that 10 contain oxygen or gases that can release oxygen under the chosen regeneration conditions. Examples that may be mentioned are nitrogen oxides, preferably N2O.

All the regeneration processes mentioned above can be carried out while the catalyst is installed in the reactor or even outside the reactor after the catalyst has been removed. Of course it is also possible to regenerate the catalyst several times 20 times Therefore, the present invention also • provides an integrated process or process as described above where the catalyst or zeolitic catalysts (s) are regenerated at least once and reused in the process. 25 i * iá * A - ******. MM. For the regeneration of the catalyst used according to the present invention, in principle it is preferable to use all the methods known from the prior art for the regeneration of the silicate-containing catalysts, particular zeolite catalysts. The deactivated catalyst is generally treated at a temperature of from 20 to 700 ° C in the presence or absence of oxygen or oxygen releasing substances so that the activity of the regenerated catalyst is greater than that of the deactivated catalyst.

Specific mention can be made as an example of the following processes: A process for regenerating a deactivated catalyst (zeolite), which consists of heating the deactivated catalyst at a temperature of less than 400 ° C but greater than 150 ° C in the presence of molecular oxygen for a period that is sufficient to increase the activity of the catalyst deactivated, as described in EP-A 0 743 094; . A process for regenerating a deactivated catalyst (zeolite), which involves heating the deactivated catalyst at a temperature from 150 ° C to 700 ° C in the presence of a gas stream containing no more than 5% by volume of molecular oxygen, for a period that is sufficient to improve the activity of the deactivated catalyst, as described in EP-A 0 790 075; A process for regenerating catalysts (zeolite), in which the deactivated catalyst is heated to a temperature of from 400 to 500 ° C in the presence of an oxygen-containing gas or washed with a solvent, preferably at a temperature which is from 5 °. C up to 150 ° C higher than the temperature used during the reaction, as described in JP-A 3 11 45 36; A process for regenerating a deactivated catalyst (zeolite) by heating it to 550 ° C in air or by washing it with solvents, so that the activity of the catalyst is restored, as described in Proc. 7th Intern. Zeolite Conf. 1986 (Tokyo); A process for regenerating a catalyst (zeolite) which consists of the following steps (a) and (b): (A) heating a at least partially deactivated catalyst at a temperature in the range from 250 ° C to 600 ° C in a atmosphere containing less than 2% by volume of oxygen, and (B) treating the catalyst at a temperature in the range from 250 to 800 ° C, preferably from 350 to 600 ° C, with a gaseous stream having a content of an oxygen or oxygen releasing substance or a mixture of two or more of these in the range from 0.1 to 4% by volume, where the process can also comprise the other steps (C) and (D), (C) treating the catalyst at a temperature in the range from 250 ° C to 800 ° C, preferably from 350 to 600 ° C, with a gaseous stream having an oxygen or oxygen releasing substance content or a mixture of two or more of these in the range from > 4-100% by volume, (D) cooling the regenerated catalyst obtained in step (C) in an inert gas stream containing up to 20% by volume of a vapor liquid selected from the group consisting of water, alcohols, aldehydes, ketones , ethers, acids, esters, nitriles, hydrocarbons and mixtures of two or more of these.

Details of this process can be found in DE-A 197 23 949.8.

In addition, it is also possible for the catalyst to be regenerated by washing it with at least one solution of hydrogen peroxide or with one or more oxidizing acids. Of course, the methods described above can be combined together in a convenient manner.

If the active components for hydrogenation as metals are applied to the zeolitic catalyst, as described herein above for a preferred embodiment of the present invention, it is possible that these are separated from the zeolite and reused for preparation step renewed catalyst.

** J **? *. ** ~ > ^ *. * -, ** L For the purpose of the present invention, of course it is also possible that the regenerated catalyst is used in another process.

The invention is illustrated by the following examples.

Examples Example 1: Preparation of MCM-22 In an agitator apparatus, 8.3 g of sodium aluminate (43.6% of Na20, 56.8% of A1203) and 5.3 g of NaOH flakes were dissolved in 200 g of deionized water. To the above solution was added a solution of sulfuric acid consisting of 1 g of H2SO4 (98% by weight) in 50 of water. The resulting solution was added with stirring to a suspension of 88 g of pyrogenic silica (Aerosil 200) in 850 g of water. Subsequently, 48 g of hexamethyleneimine were added and the mixture was homogenized for 30 minutes. The mixture reacted at 150 ° C for 288 hours, the solid was filtered and washed three times with 100 mL of water. It was then dried at 120 ° C and calcined at 500 ° C in air for 5 hours. The product showed a common X-ray diffraction pattern for MCM-22 and, according to the chemical wet analysis, had the following composition: 38.0% by weight of Si, 1.9% by weight of Al and 1.2% by weight of Na . The specific surface area determined by the Langmuir method using N2 at 77 K was 639 m / g. The material was converted to the ammonium form using a 0.1 N ammonium chloride solution, dried and again calcined at 500 ° C in air for 5 hours.

The product obtained in this way had a residual sodium content of 0.1% by weight.

Example 2: Use of MCM-22 for hydration In a glass pressure autoclave with a capacity of 50 mL, 3 g of the catalyst of Example 1 were reacted with 0.092 moles of benzene (the reaction product of the hydrogenation of benzene to cyclohexene), 0.022 moles of cyclohexene and 0.2 moles of water at 120 ° C for 5 hours with agitation. The resulting mixture of phases was homogenized after the reaction by adding dimethylformamide / methanol and analyzed by means of GC.

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

Example 3: Comparative example using β-zeolite for hydration In a glass pressure autoclave with a capacity of 50 mL, 3 g of β-zeolite in Form H were reacted with 0.092 moles of benzene, 0.022 moles of cyclohexene and 0.2 moles of water at 120 ° C for 5 hours. with agitation. The resulting mixture of phases was homogenized after the reaction by adding dimethylformamide / methanol and analyzed by means of GC. The yield of cyclohexanol based on the cyclohexene used was only 7.5 mol%.

Claims

CLAIMS A process to prepare cyclohexanol, in which: (i) the cyclohexene is hydrated in the presence of water by contacting it with at least one catalyst to form cyclohexanol, wherein the heterogeneous catalyst or catalysts (s) consist of a zeolitic catalyst with a structure MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 or a mixture of two or more of these structures . The process as claimed in claim 1, wherein the catalyst or zeolitic catalysts contains (n) at least one element of transition group I, II or VIII of the Periodic Table. The process as claimed in claim 1 or 2, in which: (ii) the cyclohexene is prepared by hydrogenation of at least one starting material. HÉ t? ni l? iit ñu ii¡iiiiiMKi ?? »i? irlr? frr? i ni ÍI ?? The process as claimed in any of claims 1 to 3, wherein the cyclohexene is prepared by selective hydrogenation of benzene as starting material. The process as claimed in any of claims 1 to 4, wherein the preparation of cyclohexene and the hydration of cyclohexene as described in (i) are carried out in a single step. The process as claimed in claim 5, wherein the zeolitic catalyst having a structure MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 or a mixture of two or more of these structures is used as support for at least one catalytically active component that is used to prepare cyclohexene by hydrogenation of benzene. The process as claimed in any of claims 1 to 4, wherein the preparation of cyclohexene as described in (i) and the hydration of cyclohexene are carried out in at least two different steps. ^ **? * ^ *** ^ *? ^ *? ** ^ *. An integrated process to prepare cyclohexanol, in which: (a) Cyclohexene is prepared by hydrogenation of benzene, (b) the reaction product of (a) containing cyclohexene and unreacted starting material goes to another step (c), (c) the cyclohexene is hydrated in the presence of water by contacting it with at least one heterogeneous catalyst, and (d) the unreacted starting material of (a) is separated from the reaction product of (c) and recycled to (a), wherein the heterogeneous catalyst or catalysts (s) consist of a zeolitic catalyst having a structure MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 or a mixture of two or more of these structures. The process as claimed in any of claims 1 to 8, wherein the catalyst or zeolitic catalysts (s) are regenerated at least once and reused in the process.