CA2388881A1 - Method for producing an alcohol from an alkene - Google Patents
Method for producing an alcohol from an alkene Download PDFInfo
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- CA2388881A1 CA2388881A1 CA002388881A CA2388881A CA2388881A1 CA 2388881 A1 CA2388881 A1 CA 2388881A1 CA 002388881 A CA002388881 A CA 002388881A CA 2388881 A CA2388881 A CA 2388881A CA 2388881 A1 CA2388881 A1 CA 2388881A1
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- cyclohexene
- metal oxide
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/03—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by addition of hydroxy groups to unsaturated carbon-to-carbon bonds, e.g. with the aid of H2O2
- C07C29/04—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by addition of hydroxy groups to unsaturated carbon-to-carbon bonds, e.g. with the aid of H2O2 by hydration of carbon-to-carbon double bonds
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C5/00—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms
- C07C5/02—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by hydrogenation
- C07C5/10—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by hydrogenation of aromatic six-membered rings
- C07C5/11—Partial hydrogenation
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C2529/00—Catalysts comprising molecular sieves
- C07C2529/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites, pillared clays
- C07C2529/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
- C07C2529/70—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of types characterised by their specific structure not provided for in groups C07C2529/08 - C07C2529/65
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C2601/00—Systems containing only non-condensed rings
- C07C2601/12—Systems containing only non-condensed rings with a six-membered ring
- C07C2601/14—The ring being saturated
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C2601/00—Systems containing only non-condensed rings
- C07C2601/12—Systems containing only non-condensed rings with a six-membered ring
- C07C2601/16—Systems containing only non-condensed rings with a six-membered ring the ring being unsaturated
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/10—Process efficiency
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Catalysts (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
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 i s 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 FaR -PA~D'UC~~TG AN AI~Ct3H~ AN AI~KENE
The present invention relates to a process for preparing an alcohol from an alkene by hydration of the alkene by means of a zeolitic catalyst having an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure 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 starting 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 such catalysts are described, for example, in Tanabe et al., Stud. Surf. Sci. Catal. 51 (19$9), pp. 247-254. There, Si02-A1203, inter alia, is disclosed as catalyst for the hydration of ethene to ethanol. However, low selectivity and therefore the formation of undesirable by-products are mentioned as disadvantages of this catalyst. This publication likewise discloses cation-exchange zeolites of type A and Y as catalysts far the preparation of ethanol, with type A, which comprises Mg, Ca, Cd, Zn, etc., allowing no by-product formation while, on the other hand, type Y makes it possible for by-products to be formed.
Specifically for the liquid-phase hydration of cyclohexene to cyclohexanol, Ishida, 2 0 Catalysis Surveys of Japan 1 (1997), pp. 241-246, makes a closer examination of zeolites of the type ZSM-5, ZSM-11, ZSM-12, ZSM-35, mordenite and Y, with ZSM-5 and ZSM-11 being mentioned as those catalysts which display acceptable by-product formation.
DE-A 34 41 072 discloses 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 acid sites on the outer surface to the total number of acid sites of 0.07 or more. Examples disclosed are, inter alia, zeolites, and examples of zeolites disclosed are in turn mordenite, faujasite, clinoptilolite, zeolite L, zeolites of the ZSM type, chabazite and erionite.
However, a disadvantage of these processes is that satisfactory conversions are achieved only when using extremely finely particulate zeolites which are difficult to remove from the reaction mixture. A pertinent improvement is described in EP-B 0 634 361. This patent discloses a specific agglomeration of pentasil zeolite particles which combines the advantages of high catalytic activity with ready reparability. However, the method of producing these agglomerates requires an outlay in terms of apparatus which may be undesirable.
It is an object of the present mention to provide a process for-preparing an alcohol from an alkene which does not have the abovementioned disadvantages.
We have found that this object is achieved by hydrating alkenes using a zeolite having an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of these structures as heterogeneous catalyst.
A zeolite of the structure MCM-22 is described, fvr example, in Kennedy et al., J.
Am. Chem. Soc. 116 (1994), pp. 10000-10003, or in Leonowicz et al., Science ( 1994), pp. 1910-1913.
The present invention accordingly provides a process for preparing at least one alcohol, in which (i) at least one alkene is hydrated in the presence of water by the bringing into 2 5 contact with at least one catalyst to form an alcohol or alcohols, wherein the heterogeneous catalyst or catalysts comprises/comprise a zeolitic catalyst having an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of these structures.
Zeolites are, as is known, crystalline aluminosilicates having ordered channel and cage structures which have micropores. The term "micropores" as used for the purposes of the present invention corresponds to the definition in Pure Appl.
Chem. 57 (1985), pp. 603-619, and refers to pores having a pore diameter of less 3 5 than 2 nm. The network of such zeolites is built up of Si04 and A104 tetrahedra which are cormected via joint oxygen bridges. An overview of these structures may be found, for example, in W.M. Meier, D.H. Olson and Ch. Baerlocher in Atlas of Zeolite Structure Types, Elsevier, 4th edition, London 1996.
The zeolitic catalyst used according to the present invention 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 here be prepared by all suitable methods of the prior art. For example, it can be prepared by a method described, for example, in US
The present invention relates to a process for preparing an alcohol from an alkene by hydration of the alkene by means of a zeolitic catalyst having an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure 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 starting 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 such catalysts are described, for example, in Tanabe et al., Stud. Surf. Sci. Catal. 51 (19$9), pp. 247-254. There, Si02-A1203, inter alia, is disclosed as catalyst for the hydration of ethene to ethanol. However, low selectivity and therefore the formation of undesirable by-products are mentioned as disadvantages of this catalyst. This publication likewise discloses cation-exchange zeolites of type A and Y as catalysts far the preparation of ethanol, with type A, which comprises Mg, Ca, Cd, Zn, etc., allowing no by-product formation while, on the other hand, type Y makes it possible for by-products to be formed.
Specifically for the liquid-phase hydration of cyclohexene to cyclohexanol, Ishida, 2 0 Catalysis Surveys of Japan 1 (1997), pp. 241-246, makes a closer examination of zeolites of the type ZSM-5, ZSM-11, ZSM-12, ZSM-35, mordenite and Y, with ZSM-5 and ZSM-11 being mentioned as those catalysts which display acceptable by-product formation.
DE-A 34 41 072 discloses 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 acid sites on the outer surface to the total number of acid sites of 0.07 or more. Examples disclosed are, inter alia, zeolites, and examples of zeolites disclosed are in turn mordenite, faujasite, clinoptilolite, zeolite L, zeolites of the ZSM type, chabazite and erionite.
However, a disadvantage of these processes is that satisfactory conversions are achieved only when using extremely finely particulate zeolites which are difficult to remove from the reaction mixture. A pertinent improvement is described in EP-B 0 634 361. This patent discloses a specific agglomeration of pentasil zeolite particles which combines the advantages of high catalytic activity with ready reparability. However, the method of producing these agglomerates requires an outlay in terms of apparatus which may be undesirable.
It is an object of the present mention to provide a process for-preparing an alcohol from an alkene which does not have the abovementioned disadvantages.
We have found that this object is achieved by hydrating alkenes using a zeolite having an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of these structures as heterogeneous catalyst.
A zeolite of the structure MCM-22 is described, fvr example, in Kennedy et al., J.
Am. Chem. Soc. 116 (1994), pp. 10000-10003, or in Leonowicz et al., Science ( 1994), pp. 1910-1913.
The present invention accordingly provides a process for preparing at least one alcohol, in which (i) at least one alkene is hydrated in the presence of water by the bringing into 2 5 contact with at least one catalyst to form an alcohol or alcohols, wherein the heterogeneous catalyst or catalysts comprises/comprise a zeolitic catalyst having an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of these structures.
Zeolites are, as is known, crystalline aluminosilicates having ordered channel and cage structures which have micropores. The term "micropores" as used for the purposes of the present invention corresponds to the definition in Pure Appl.
Chem. 57 (1985), pp. 603-619, and refers to pores having a pore diameter of less 3 5 than 2 nm. The network of such zeolites is built up of Si04 and A104 tetrahedra which are cormected via joint oxygen bridges. An overview of these structures may be found, for example, in W.M. Meier, D.H. Olson and Ch. Baerlocher in Atlas of Zeolite Structure Types, Elsevier, 4th edition, London 1996.
The zeolitic catalyst used according to the present invention 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 here be prepared by all suitable 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 an Si:AI
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 used according to the present invention, determined by the Langmuir method, is preferably in the range from 400 to 1000 m2/g, more preferably in the range from 450 to 850 m2/g and particularly preferably in the range from 500 to 750 m2/g.
One of the advantages offered by, for example, the type MCM-22 used according to the present invention is that zeolites of this type are, owing to their 2 0 crystallization form, obtained as agglomerates of thin platelets and accordingly have a high activity per unit mass.
It is also conceivable for the zeolite used according to the present invention to comprise further elements. For example, it preferably comprises at least one 2 5 element of transition groups I, II and VIII. The present invention therefore also provides a process as described above in which the zeolitic catalyst or catalysts comprises/comprise 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 used according to the present invention can likewise contain elements Ga and B.
As regards the form in which the catalyst is used in the process of the present 3 5 invention, all suitable geometries are generally possible. Thus, for instance, the above-described platelet agglomerates themselves can be used. It is also possible to process the zeolite by a suitable method to give a shaped body.
To produce the shaped bodies, the zeolite can, for example, be mixed with a binder, an organic viscosity-increasing substance and a liquid for forming a paste and be compounded in a kneader or-pan mill. The mass obtained can subsequently also be shaped by means of a ram extruder or screw extruder. The shaped bodies obtained are subsequently dried and, if appropriate, calcined.
To produce shaped bodies which are also suitable for preparing very reactive products, it is necessary to use chemically inert binders which prevent further reaction of these products.
A series of metal oxides are suitable as binders. Mention may be made, for example, of oxides of silicon, of aluminum, of titanium or of zirconium.
Silicon dioxide as binder is disclosed, for example, in the patents US 5,500,199 and US
4,859,785.
In such binders, it may be necessary, for example, for the content of alkali metal or alkaline earth metal ions to be very low, making it necessary to use binder sources which are low in or free of alkali metals or alkaline earth metals.
As starting material for preparing the abovementioned metal oxide binders, it is possible to use corresponding metal oxide sots. In the preparation of, for example, the abovementioned silicon dioxide binder which is low in or free of alkali metals and alkaline earth metals, silica sol which is low in or free of alkali metals or 2 5 alkaline earth metals accordingly serves as binder source.
Such shaped bodies can be obtained, inter alia, by, in one step of the process, mixing the zeolite with metal oxide sol and/or metal oxide, where the metal oxide sol and the metal oxide in each case have a low content of alkali metal and alkaline 3 0 earth metal ions. Accordingly, the present invention also describes a process in which a shaped body comprising at least one zeolite having an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of these structures and at least one metal oxide, where (I) the zeolite or zeolites is/are mixed with at least one metal oxide sol which 3 5 has a low content of alkali metal and alkaline earth metal ions and/or at least one metal oxide which has a low content of alkali metal and alkaline earth metal ions.
In particular, the catalysts according to the present invention have an Si:AI
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 used according to the present invention, determined by the Langmuir method, is preferably in the range from 400 to 1000 m2/g, more preferably in the range from 450 to 850 m2/g and particularly preferably in the range from 500 to 750 m2/g.
One of the advantages offered by, for example, the type MCM-22 used according to the present invention is that zeolites of this type are, owing to their 2 0 crystallization form, obtained as agglomerates of thin platelets and accordingly have a high activity per unit mass.
It is also conceivable for the zeolite used according to the present invention to comprise further elements. For example, it preferably comprises at least one 2 5 element of transition groups I, II and VIII. The present invention therefore also provides a process as described above in which the zeolitic catalyst or catalysts comprises/comprise 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 used according to the present invention can likewise contain elements Ga and B.
As regards the form in which the catalyst is used in the process of the present 3 5 invention, all suitable geometries are generally possible. Thus, for instance, the above-described platelet agglomerates themselves can be used. It is also possible to process the zeolite by a suitable method to give a shaped body.
To produce the shaped bodies, the zeolite can, for example, be mixed with a binder, an organic viscosity-increasing substance and a liquid for forming a paste and be compounded in a kneader or-pan mill. The mass obtained can subsequently also be shaped by means of a ram extruder or screw extruder. The shaped bodies obtained are subsequently dried and, if appropriate, calcined.
To produce shaped bodies which are also suitable for preparing very reactive products, it is necessary to use chemically inert binders which prevent further reaction of these products.
A series of metal oxides are suitable as binders. Mention may be made, for example, of oxides of silicon, of aluminum, of titanium or of zirconium.
Silicon dioxide as binder is disclosed, for example, in the patents US 5,500,199 and US
4,859,785.
In such binders, it may be necessary, for example, for the content of alkali metal or alkaline earth metal ions to be very low, making it necessary to use binder sources which are low in or free of alkali metals or alkaline earth metals.
As starting material for preparing the abovementioned metal oxide binders, it is possible to use corresponding metal oxide sots. In the preparation of, for example, the abovementioned silicon dioxide binder which is low in or free of alkali metals and alkaline earth metals, silica sol which is low in or free of alkali metals or 2 5 alkaline earth metals accordingly serves as binder source.
Such shaped bodies can be obtained, inter alia, by, in one step of the process, mixing the zeolite with metal oxide sol and/or metal oxide, where the metal oxide sol and the metal oxide in each case have a low content of alkali metal and alkaline 3 0 earth metal ions. Accordingly, the present invention also describes a process in which a shaped body comprising at least one zeolite having an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of these structures and at least one metal oxide, where (I) the zeolite or zeolites is/are mixed with at least one metal oxide sol which 3 5 has a low content of alkali metal and alkaline earth metal ions and/or at least one metal oxide which has a low content of alkali metal and alkaline earth metal ions.
In a preferred embadiment of the process of the present invention, the metal oxide sol is prepared by hydrolysis of at least one metallic ester.
The metallic esters employed for the hydrolysis can be purified prior to the hydrolysis. All suitable methods are conceivable for this purpose. The metallic esters are preferably subjected to distillation prior to the hydrolysis.
As regards the hydrolysis of the metallic ester, it is in principle 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 addition of basic or acidic substances.
Preference is given to basic or acidic substances which can be removed without leaving a residue 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 using ammonia, alkylamines, alkanolamines and carboxylic acids.
2 0 Preferred metallic esters for the purposes of the process of the present invention are, inter alia, orthosilicic esters.
In the process of the present invention, the hydrolysis of the metallic esters is carned out at from 20 to 100°C, preferably from 60 to 95°C, and at a pH of from 4 2 5 to 10, preferably from 5 to 9, particularly preferably from 7 to 9.
In the process of the present invention, the hydrolysis gives metal oxide sots, preferably silica sols, which have, for example, a content of alkali metal and alkaline earth metal ions of less than 800 ppm, preferably less than 600 ppm, more 3 0 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, in particular less than 5 ppm.
The metal oxide content of the metal oxide sol prepared according to the present 3 5 invention is generally up to 50% by weight, preferably from 10 to 40% by weight.
The metallic esters employed for the hydrolysis can be purified prior to the hydrolysis. All suitable methods are conceivable for this purpose. The metallic esters are preferably subjected to distillation prior to the hydrolysis.
As regards the hydrolysis of the metallic ester, it is in principle 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 addition of basic or acidic substances.
Preference is given to basic or acidic substances which can be removed without leaving a residue 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 using ammonia, alkylamines, alkanolamines and carboxylic acids.
2 0 Preferred metallic esters for the purposes of the process of the present invention are, inter alia, orthosilicic esters.
In the process of the present invention, the hydrolysis of the metallic esters is carned out at from 20 to 100°C, preferably from 60 to 95°C, and at a pH of from 4 2 5 to 10, preferably from 5 to 9, particularly preferably from 7 to 9.
In the process of the present invention, the hydrolysis gives metal oxide sots, preferably silica sols, which have, for example, a content of alkali metal and alkaline earth metal ions of less than 800 ppm, preferably less than 600 ppm, more 3 0 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, in particular less than 5 ppm.
The metal oxide content of the metal oxide sol prepared according to the present 3 5 invention is generally up to 50% by weight, preferably from 10 to 40% by weight.
'The alcohol formed in the hydrolysis is generally distilled off in the process of the present invention. However, small amounts of alcohol can remain in the metal oxide sol as long as they do not interfere in further steps of the process of the present invention.
An advantage for the industrial use of the metal oxide sots prepared according to the present invention is the fact that they display no tendency to form a gel.
Specific precautions for preventing gel formation are thus superfluous. The metal oxide sots prepared according to the present invention can be stored for a number of weeks, making timewise coordination with further steps unproblematical.
In the process of the present invention, a mixture comprising the zeolite or zeolites having an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of these structures and at least one metal oxide is prepared using a metal oxide sol prepared as described above as metal oxide source.
In principle, there are no restrictions as regards the method of preparing the mixture. However, in the process of the present invention preference is given to spraying a suspension comprising the zeolite or zeolites having an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of 2 0 these structures and a metal oxide sol.
As regards the zeolite content of the suspension, there are no restrictions as long as the processability of the suspension during preparation and spraying is ensured.
The weight ratio of zeolite to metal oxide of the metal oxide sol is preferably 2 5 chosen so as 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 can also contain residual traces of organic compounds.
3 0 These can originate, for example, from the preparation of the zeolite. It is likewise conceivable for alcohols formed in the hydrolysis of metallic esters or substances which are added as described above for promoting the hydrolysis of metallic esters to be present.
3 5 Depending on the moisture content which the mixture is to have for further processing, drying can follow. Here, all conceivable methods can be employed.
Drying of the mixture is preferably corned out simultaneously with spraying in a spray-drying procedure. The spray dryers are preferably operated using inert gases, particularly preferably nitrogen or argon.
In a likewise preferred embodiment of the process of the present invention, 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 structures is mixed in (I) with at least one metal oxide which has a low content of alkali metal and alkaline earth metal ions.
If the zeolite is mixed with two or more metal oxides, it is conceivable for the zeolite to be mixed firstly with the one metal oxide and the resulting mixture to be mixed with a further-metal oxide. If desired, the mixture obtained here can in turn be mixed with a further-metal oxide. It is likewise possible to mix the zeolite with a mixture of two ormore 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.
2 0 Examples of such metal oxides having a low content of alkali metal and alkaline earth metal ions are pyrogenic metal oxides, for example pyrogenic silica.
In the process of the present invention, it is naturally also possible for the mixture resulting from the mixing of the zeolite with the metal oxide to be mixed with at least one metal oxide sol which has, if appropriate, a low content of alkali metal 2 5 and alkaline earth metal ions. With regard to the preparation of this mixture, there are in principle no restrictions, as in the preparation of the mixture of zeolite and metal oxide sol described above. However, preference is given to spraying a suspension comprising the mixture of the zeolite or zeolites and the metal oxide or oxides and the metal oxide sol or sols. There are no restricions in respect of the 3 0 zeolite content of this suspension, as long as, as described above, the processability of the suspension is ensured.
Furthermore, in the process of the present invention it is naturally also possible for a mixture resulting from the mixing of at least one zeolite having an MCM-22, 3 5 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 to be mixed with at least one metal oxide which has, if appropriate, a low content of alkali metal and alkaline _g-earth metal ions. Here, mixing with the metal oxide or oxides can directly follow the preparation of the mixture of the zeolite or zeolites having 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 metal oxide sol or sols. Should, as described above, drying be necessary after the preparation of the mixture of the zeolite or zeolites having 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 metal oxide sol or sols, it is also possible to mix the metal oxide with the dried mixture after drying.
It is likewise possible in the process of the present invention to mix the zeolite or zeolites having an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or -more of these structures simultaneously 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 compounded in a further step of the process of the present invention.
In this compounding or shaping step, fiwther metal oxide can be introduced if desired, using a metal oxide sol prepared as described above as metal oxide source.
This processing step can be carried out in all apparatuses known for this purpose, 2 0 but preference is given to kneaders, pan mills or extruders. A pan mill is particularly preferred for industrial implementation of the process of the present invention.
If, according to one of the above-described embodiments, a mixture of the zeolite 2 5 having an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of these structures and at least one metal oxide is prepared first, this mixture is compounded and a metal oxide sol having a low content of alkali metal and alkaline earth metal ions is additionally added in the compounding step, then, in a preferred embodiment of the present invention, use is made of from 20 to 80%
3 0 by weight of zeolite, from 10 to 60% by weight of metal oxide and from 5 to 30%
by weight of metal oxide sol. Particular preference is given to using 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 metal oxide sol. These percentages are in each case based on the final shaped body produced, as described below.
In a further embodiment of the process of the present invention, the mixing of the zeolite or zeolites having an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or mare of these structures with the metal oxide or oxides which, if appropriate, has/have a low content of alkali metal and alkaline earth metal ions is carried out during the compounding step. It is likewise possible to mix the zeolite or zeolites having an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two ormore of these structures, the metal oxide or oxides and additionally at least one-metal oxide sol in the compounding step.
In this shaping step, it is possible to additionally add one or more viscosity-increasing substances as pasting agents which serve, inter olio, to increase the stability of the uncalcined shaped body, as described below. All suitable substances known from the prior art can be used for this purpose. In the process of the present invention, water or mixtures of water-with one or more organic substances which are miscible with water are used as pasting agent. The pasting agent can be removed again during the later-calcination of the shaped body.
Preference is given to using organic, in particular hydrophilic organic polymers such as cellulose, cellulose derivatives, e.g. methylcellulose, ethylcellulose or hexylcellulose, polyvinylpyrrolidone, ammonium (meth)acrylates, Tylose or mixtures of two or more thereof. Particular preference is given to using 2 0 methylcellulose.
Further additives which can be added are ammonia, amines or amine-like compounds, e.g. tetraalkylammonium compounds or aminoalkoxides. Such further additives are described in EP-A 0 389 041, EP-A 0 200 260 and WO 95/ 19222, 2 5 the full disclosure of which in this respect is hereby incorporated by reference into the present application.
Instead of basic additives, it is also possible to use acidic additives.
Preference is given to acidic organic compounds which can be burnt out by calcination after the 3 0 shaping step. Particular-preference is given to carboxylic acids.
The amount 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 shaped body produced, as described below.
To influence the properties of the shaped body, e.g. transport pore volume, transport pore diameter and transport pore distribution, it is possible to add further substances, preferably organic compounds, in particular organic polymers, as further additives which can also influence the shapeability of the composition.
Such additives include alginates, polyvinylpyrrolidones, starch, cellulose, polyethers, polyesters, polyamides, polyamines, polyimines, polyalkenes, polystyrene, styrene copolymers, polyacrylates, polymethacrylates, fatty acids such as stearic acid, high molecular weight polyalkylene glycols such as polyethylene glycol, polypropylene glycol or polybutylene glycol and mixtures of two or more thereof. The total amount of these substances, based on the final shaped body produced, as described below, is preferably from 0.5 to 10% by weight, particularly preferably from 1 to 6% by weight.
In a preferred embodiment, shaped bodies which are essentially microporous but can additionally have mesopores and/or macropores are produced in the process of the present invention.
The order of addition of the above-described additives to the mixture obtained according to one of the above-described methods is not critical. It is possible either to introduce firstly further metal oxide via metal oxide sol, followed by the viscosity-increasing substances and then the substances which influence the 2 0 transport properties and/or the shapeability of the compounded composition, or to use any other order of addition.
If desired, the generally still pulverulent mixture can be homogenized for from 10 to 180 minutes in the kneader or extruder prior to compounding. This is generally 2 5 carried out in a temperature range from about 10°C to the boiling point of the pasting agent and under atmospheric pressure or slightly superatmospheric pressure. The mixture is kneaded until an extrudable composition has been formed.
The composition which has been compounded and is ready far shaping has, in the 3 0 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, kneading and shaping can be carried out using all conventional 3 5 kneading and shaping apparatuses and methods which are known in large numbers from the prior art and are suitable for the production of, for example, shaped catalyst bodies.
Preference is given to using methods in which shaping is carried out by extrusion in customary extruders, for example to give extrudates having a diameter of usually from about 1 to about 10 mm, in particular from about 1.5 to about 5 mm.
Such extrusion apparatuses are described, for example, in "Ullmanns Enzyklopadie der Technischen Chemie", 4th edition, Volume 2 (1972), pp. 95 ff. Apart from the use of a screw extruder, preference is likewise given to using a ram extruder.
For industrial use of the process, purticular-preference is given to screw extruders.
The extrudates are either rods or honeycombs. The honeycombs can have any shape. They can be, for example, round extrudates, hollow extrudates or star-shaped extrudates. T'he honeycombs can also have any diameter. The external shape and the diameter are generally decided by process engineering requirements for the process in which the shaped body is to be used.
After completion of extrusion, the shaped bodies obtained are dried at generally from 50 to 250°C, preferably from 80 to 250°C, at pressures of generally from 0.01 to 5 bar, preferably from 0.05 to 1.5 bar, for from about 1 to 20 hours.
2 0 Subsequent calcination is carried out at 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 for drying. Calcination is generally carried out in an oxygen-containing atmosphere having an oxygen content of from 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 shaped bodies as described above, in which (I) the zeolite or zeolites having an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of these structures is mixed 3 0 with at least ane 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 from (I), with or without addition of metal oxide sol, is 3 5 compounded;
(III)the composition from (II) is shaped to give a shaped body;
(IV) the shaped body from (III) is dried and (V) the dried shaped body from (IV) is calcined.
A specific embodiment of the invention comprises adding the metal oxide sol to the above-described suspension, drying the resulting suspension, preferably by spray drying, and calcining the resulting powder. The dried and calcined product can then be furrherprocesssed as described in (III).
Of course, the extrudates obtained can be converted into a finished form. All methods of comminution are conceivable here, for example by crushing or breaking the shaped bodies; further chemical treatments, for example as described above, are likewise possible. If comminution takes place, granules or chippings having a particle diameter of from 0.1 to 5 mm, in particular from 0.5 to 2 mm, are preferably produced.
These granules or chippings and also shaped bodies produced in another way contain virtually no material having a particle diameter of less than about 0.1 mm.
As support material for the catalytically active component, namely 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 structures, it is also possible to use all other suitable materials. Examples which may be mentioned are shaped bodies or packing made 2 5 of metal, ceramic or plastics, for instance distillation packing, static mixers, mesh packing or resin beads. 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 structures can be deposited and immobilized on these materials by all conceivable and suitable methods. Such methods are disclosed, for example, in DE-C 42 16 846.5 and DE-3 0 A 196 07 577.7, the full disclosure of which on this subject is hereby incorporated by reference into the present application.
The alkene which is hydrated as described in (i) can in principle come from any suitable source, for example can be prepared by any suitable process. It is possible 3 5 to hydrate, inter alia, alkenes having from 2 to 20 carbon atoms. It is likewise conceivable for the alkenes to be hydrated to have not only at least one C-C
double bond but also further functional groups which may also be able to undergo hydration. Furthermore, alkenes which are substituted in a suitable fashion can be used. Examples of suitable alkenes are:
ethane, propane, 1-butane, 2-butane, isobutene, butadiene, pentanes, piperylene, hexenes, hexadienes, heptenes, octenes, diisobutene, trimethylpentene, nonenes, dodecene, tridecene, tetradecenes to eicosenes, tripropene and tetrapropene, polybutadienes, polyisobutenes, isoprene, terpenes, geraniol, linalool, linalyl acetate, methylenecyclopropane, cyclopentene, cyclohexene, norbornene, cycloheptene, vinylcyclohexane, vinyloxirane, vinylcyclohexene, styrene, cyclooctene, cyclooctadiene, vinylnorbornene, indene, tetrahydroindene, methylstyrene, dicyclopentadiene, divinylbenzene, cyclododecene, cyclododecatriene, stilbene, diphenylbutadiene, vitamin A, beta-carotene, vinylidene fluoride, allyl halides, crotyl chloride, methallyl chloride, dichlorobutene, allyl alcohol, methallyl alcohol, butenols, butenediols, cyclopentenediols, pentenols, octadienols, tridecenols, unsaturated steroids, ethoxyethene, isoeugenol, anethole, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, malefic acid, vinylacetic acid, unsaturated fatty acids such as oleic acid, linoleic acid, palmitic acid, naturally occurring fats and oils.
Particular preference is given to preparing the alkene itself in the process of the present invention from suitable starting materials, with the alkene preferably being prepared from at least one starting material by hydrogenation of this starting material. Preference is given to preparing alkenes having from 2 to 6 carbon atoms 2 5 from at least one starting material, with these alkenes also being able to have more than one C-C double bond. The present invention therefore also provides a process as described above in which (ii) the alkene or alkenes is/are prepared by hydrogenation of at least one 3 0 starting material.
It is possible, inter alia, for the alkene to be prepared by selective hydrogenation of a compound having at least one C-C triple bond. It is likewise possible, starting from a starting material having at least two C-C double bonds, to prepare the 3 5 alkene by selectively hydrogenating at least one C-C double bond of the starting material and leaving at least one C-C double bond in the hydrogenated starting material. Of course, it is also conceivable for starting materials having, for example, at least one C-C double bond and at least ane further functional group capable of hydrogenation to be selectively hydrogenated in such a way that the hydrogenated starting-material has at least one C-C double bond.
Other functional groups capable of hydration other than C-C double bonds can of course also be hydrated in the process of the present invention. Examples which may be mentioned are cyano groups, carboxylic ester groups or carbvxamide groups. As mentioned above, one or-mvre of these functional groups can 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 hydrating cyclic alkenes. In principle, the cyclic alkenes which are preferably used can come from all conceivable sources; they are particularly preferably, as described above, prepared from all suitable starting materials by hydrogenation. In a very particularly preferred embodiment, the present invention provides a process as described above wherein the alkene or alkenes is/are cycloalkene and is/are prepared by selective hydrogenation of benzene as starting material. The selective hydrogenation of benzene can, for example, be corned out by a process 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 alkene or alkenes prepared in this way are carried out in a single step. The term "single step" means, for the purposes of the present application, that the suitable starting material or materials is/are hydrogenated in at 2 5 least one suitable reactor and the alkene prepared in this way is hydrated in the same reactor. The present invention therefore also provides a process as described above 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.
3 0 It is conceivable that, for example, the catalyst or catalysts required for the hydrogenation and the catalyst or catalysts required for the hydration are used in different ways. Here, it is conceivable that, for example, the hydrogenation catalyst or catalysts is/are used as a fixed bed and the hydration catalyst or catalysts is/are used in suspension or the hydrogenation catalyst or catalysts is/are used in 3 5 suspension and the hydration catalyst or catalysts is/are used as a fixed bed or the hydrogenation catalyst or catalysts and the hydration catalyst or catalysts are both used in suspension or as a fixed bed.
In a further embodiment, the process of the present invention is carried out as a reactive distillation. Here, it is conceivable, for example, to use at least one hydrogenation catalyst in, for example, suspension or a fixed bed, while at least one hydrogenation catalyst is applied, for example as a thin layer, to the distillation packing or packings used to separate the organic phase from the aqueous phase.
Likewise, it is of course conceivable for both at least one hydrogenation catalyst and at least one hydration catalyst to be applied as, for example, a thin layer to the distillation packing or packings used for the separation. It is of course also conceivable to use both hydrogenation and hydration catalysts in either suspension or a fixed bed and at the same time to load the distillation packing or packings used with at least one hydration catalyst or both at least one hydration catalyst and at least one hydrogenation catalyst.
It is likewise conceivable for, for example, interior-walls of pipes and/or the reactor which are in contact with compounds to be hydrogenated and/or to be hydrated to be loaded, for example coated, with the appropriate catalyst.
In a preferred embodiment of the process of the present invention, the 2 0 hydrogenation catalyst or catalysts and the hydration catalyst or catalysts are used as a single catalyst system. The present invention therefore also provides a process as described above in which the zeolite having an MCM-22, MCM-36, MCM-49, PSH-3 or TTQ-2 structure or a mixture of two or more of these structures is used as support for at least one catalytically active component used for preparing the 2 5 alkene by hydrogenation of at least one starting material.
Here, it is conceivable, for example, to apply at least one hydrogenation-active component by any suitable method of the prior art to the zeolite having an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or 3 0 more of these structures. The resulting compound can then, for example, be used as such either in a fixed bed or in suspension. It is likewise conceivable to apply the resulting compound, as described above, to the distillation packing or packings used for separating the organic phase from the aqueous phase in the reactive distillation. It is likewise possible to apply the resulting compound to interior walls 3 5 of, for example, the reactor ar pipes, for example in the form of a thin layer. As regards the application of the hydrogenation-active component to the zeolite and the presence of the hydrogenation-active component on the zeolite, reference may be made to DE-A 44 25 672, the full disclosure of which on this subject is hereby incorporated by reference into the present application.
It is likewise conceivable to produce a shaped body in a way described in detail above, in which case at least one hydrogenation-active component is incorporated in addition to 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 structures. Thus, for example, zeolite and hydrogenation-active component can firstly be mixed and subsequently shaped together with metal oxide sol and/or metal oxide by any suitable methods.
It is possible, for example, to subject the mixture of zeolite and hydrogenation-active component together with metal oxide sol to at least one spray-drying step and subsequently, with or without addition of pasting agents, to shape the spray-dried product, with kneaders or pan mills, for example, being able to be used for shaping. It is also conceivable to produce a shaped body as described above from at least zevlite and binder and to apply at least one hydrogenation-active component to the shaped body. These shaped bodies can subsequently be used, for example, in suspension or as a fixed bed in the process of the present invention.
These shaped bodies can also be used, for example, as coatings on distillation 2 0 packing for reactive distillation or on interior walls of the reactor and/or pipes, as described above.
In a further preferred embodiment, the process of the present invention is carried out by carrying out hydrogenation and hydration in at least two different steps. The 2 5 present invention therefore also provides a process as described above 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 a~s described in (ii) using all conceivable 3 0 processes of the prior art, in particular by hydrogenation of at least one suitable starting material using arty conceivable process. There are generally no restrictions in respect of the hydrogenation catalyst or catalysts preferably used here.
After preparation of the alkene, it can be separated by all conceivable and suitable methods from the reaction mixture resulting from (ii) and passed to the hydration 3 5 as described in (i). It goes without saying that the hydrogenation can in principle be carried out in a plurality of stages.
In a further preferred embodiment of the process of the present invention, the reaction mixture formed in the hydrogenation described in (i) is passed without further work-up to the hydration as described in (i).
In a further particularly preferred embodiment of the process, unreacted starting material still present in the reaction product from (ii) is, after the hydration step or steps (i), separated from the reaction product from (i) and is recycled to the hydrogenation as described in (ii). The present invention therefore 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 starting material, (b) the reaction product from (a) comprising the alkene or alkenes and unreacted starting material is passed to a further step (c), (c) the alkene or alkenes is/are hydrated in the presence of water by bringing into contact with at least one heterogeneous catalyst, and 2 0 (d) the unreacted starting material from (a) is separated from the reaction product from (c) and is recycled to (a), wherein the heterogeneous catalyst or catalysts comprises/cvmprise a zeolitic catalyst having an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a 2 5 mixture of two or more of these structures.
In step (a), particular preference is given to preparing cyclic alkenes, especially cyclohexene by selective hydrogenation of benzene. The present invention therefore also provides an integrated process as described above in which the 3 0 alcohol is cyclohexanol, the alkene is cyclohexene and the unreacted starting material which is recycled to (a) is benzene.
In the process of the present invention, it is of course quite generally conceivable for a plurality of alkenes to be prepared in (ii) either simultaneously or in a 3 5 plurality of steps which can also be carried out in different ways. It is likewise conceivable for a plurality of alkenes to be prepared either simultaneously or in a plurality of steps, which may also be carned out in different ways, by hydrogenation of suitable starting materials.
It is also possible to use two or more alkenes in (i), where at least one of these alkenes is com~erted into one alcohol or, depending on the number of C-C
double bonds capable of hydrogenation, a plurality of alcohols.
If the preparation of the alkene or alkenes to be hydrated and the hydration itself are carned out in separate steps, each step can be carned out, depending on the starting materials, in the liquid phase, in the gas phase or in the supercritical phase.
It is likewise conceivable for each step to be carried out 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 quite generally the reaction mixture from the preparation of the alkene or alkenes, water and the catalyst or catalysts having 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 can be fed into the reactor or reactors used for the hydration. For example solvents suitable 2 0 for hydration can be fed into the~hydration reactor or reactors.
The hydration is preferably carried out at from 50 to 250°C and at residence times of the reaction mixture in the reactor-in the range from 0.5 to 8 hours.
2 5 Should the activity of the catalyst having an MCM-22, MCM-36, MCM-49, PSH-or ITQ-2 structure or a mixture of two or more of these structures decrease during the course of the reaction, the present invention provides for it to be regenerated if desired. Thus, for example, it is possible to wash it with a suitable solvent at, if appropriate, elevated temperature or superatmaspheric pressure or at 3 0 superatmospheric pressure and elevated temperature.
In a liquid-phase reaction, possible washing media are, inter alia, oxidizing agents such as oxidizing acids or peroxide solutions, e.g. hydrogen peroxide. In the supercritical phase, it is also possible to use, for example, carbon dioxide as 3 5 washing medium. Likewise, the catalyst to be regenerated can be treated at increased temperature and/or increased pressure with a suitable gas mixture which is able to increase the activity of the deactivated catalyst. Here, preference is given to using, for example, oxygen-contairring gases or gases which can liberate oxygen under the regeneration conditions chosen. Examples which may be mentioned are nitrogen oxides, preferably N20.
All the abovementioned regeneration procedures can be carried out while the catalyst is installed in the reactor or else outside the reactor after the catalyst has been taken out. It is of course also possible to regenerate the catalyst a number of times. The present invention therefore also provides a process or an integrated process as described above wherein the zeolitic catalyst or catalysts is/are regenerated at least once and is/are reused in the process.
For the regeneration of the catalyst used according to the present invention, it is in principle preferable to use all methods known from the prior art for the regeneration of silicate-containing catalysts, in particular zeolite catalysts. The deactivated catalyst is generally treated at 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 higher than that of the deactivated catalyst.
Specific mention may be made by way of example of the following processes:
2.0 1. a process for regenerating a deactivated (zeolite) catalyst, which comprises heating the deactivated catalyst at a temperature of less than 400°C
but higher than 150°C in the presence of molecular oxygen for a period which is sufficient to increase the activity of the deactivated catalyst, as is 2 5 described in EP-A 0 743 094;
2. a process for regenerating a deactivated (zeolite) catalyst, which comprises heating the deactivated catalyst at from 150°C to 700°C in the presence of a gas stream containing no more than 5% by volume of molecular oxygen for 3 0 a period which is sufficient to improve the activity of the deactivated catalyst, as is described in EP-A 0 790 075;
3. a process for regenerating (zeolite) catalysts, in which the deactivated catalyst is heated at from 400 to 500°C in the presence of an oxygen-3 5 containing gas or is washed with a solvent, preferably at a temperature which is from 5°C to 150°C higher than the temperature used during the reaction, as is described in JP-A 3 11 45 36;
4. a process for regenerating a deactivated (zeolite) catalyst by calcining it at 550°C in air or by washing with solvents, so that the activity of the catalyst is restored, as described in Proc. 7th Intern. Zeolite Conf. 1986 (Tokyo);
5. a process for regenerating a (zeolite) catalyst, which comprises steps (A) and (B) below:
(A) heating an at least partially deactivated catalyst to a temperature in the range from 250°C to 600°C in an 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 gas stream having a content of an oxygen-releasing substance or oxygen or a mixture of two or more thereof in the range from 0.1 to 4% by volume, where the process may also comprise the further steps (C) and (D), 2 0 (C) treating the catalyst at a temperature in the range from 250 to 800°C, preferably from 350 to 600°C, with a gas stream having a content of an oxygen-releasing substance or oxygen or a mixture of two or more thereof in the range from > 4 to 100% by volume, 2 5 (D) cooling the regenerated catalyst obtained in step (C) in an inert gas stream containing up to 20% by volume of a liquid vapor selected from the group consisting of water, alcohols, aldehydes, ketones, ethers, acids, esters, nitrites, hydrocarbons and mixtures of two or more thereof.
Details of this process may be found in DE-A 197 23 949.8.
Furthermore, it is likewise conceivable for the catalyst to be regenerated by washing with at least one hydrogen peroxide solution or with one or more 3 5 oxidizing acids. Of course, the above-described methods can be combined with one another in a suitable fashion.
If hydrogenation-active components such as metals are applied to the zeolitic catalyst, as is described above for a preferred embodiment of the present invention, it is possible for these to be detached from the zeolite and reused for a renewed catalyst preparation step.
For the purposes of the present invention, it is of course also conceivable for the regenerated catalyst to be used in another process.
The invention is illustrated by the following examples.
Ezamples:
Example 1: Preparation of MCM-22 In a stirred apparatus, 8.3 g of sodium aluminate (43.6% of Na20, 56.8% A1203) and 5.3 g of NaOH flakes were dissolved in 200 g of deionized water. A
sulfuric acid solution consisting of 1 g of HZS04 (98% by weight) in 50 g of water was added to the above solution. T'he resulting solution was added while stirring to a suspension of 88 g of pyrogenic silica (Aerosil 200) in 850 g of water. 48 g of 2 0 hexamethyleneimine were subsequently added and the mixture was homogenized for 30 minutes. The mixture was reacted at 150°C for 288 hours, the solid was filtered off and washed three times with 100 ml of water. It was subsequently dried at 120°C and calcined at 500°C in air for 5 hours. 'The product displayed an X-ray diffraction pattern typical for MCM-22 and, according to wet chemical analysis, had the following composition: 38.0% by weight of Si, 1.9% by weight of Al and 1.2% by weight of Na. T'he specific surface area determined by the Langmuir method using N2 at 77 K was 639 m2/g. The material was converted into 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 3 5 In a 50 ml capacity glass pressure autoclave, 3 g of the catalsyt from Example 1 were reacted with 0.092 mol of benzene (reaction product from the hydrogenation of benzene to cyclohexene), 0.022 mol of cyclohexene and 0.2 mol of water at 120°C for 5 hours while stirring. The resulting phase mixture was homogenized after the reaction by addition of dimetlrylformarnide/methanol and analyzed by means of GC.
The yield of cyclohexanol based on cyclohexene used was 9.2 mol%.
Example 3 : Comparative example using [3-zeolite for the hydration In a 50 ml capacity glass pressure autoclave, 3 g of ~-zeolite in the H form were reacted with 0.092 mol of benzene, 0.022 mol of cyclohexene and 0.2 mol of water at 120°C for 5 hours while stirring. 'The resulting phase mixture was homogenized after the reaction by addition of dimethylformamide/methanol and analyzed by means of GC. The yield of cyclohexanol based an cyclohexene used was only 7.5 mol%.
An advantage for the industrial use of the metal oxide sots prepared according to the present invention is the fact that they display no tendency to form a gel.
Specific precautions for preventing gel formation are thus superfluous. The metal oxide sots prepared according to the present invention can be stored for a number of weeks, making timewise coordination with further steps unproblematical.
In the process of the present invention, a mixture comprising the zeolite or zeolites having an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of these structures and at least one metal oxide is prepared using a metal oxide sol prepared as described above as metal oxide source.
In principle, there are no restrictions as regards the method of preparing the mixture. However, in the process of the present invention preference is given to spraying a suspension comprising the zeolite or zeolites having an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of 2 0 these structures and a metal oxide sol.
As regards the zeolite content of the suspension, there are no restrictions as long as the processability of the suspension during preparation and spraying is ensured.
The weight ratio of zeolite to metal oxide of the metal oxide sol is preferably 2 5 chosen so as 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 can also contain residual traces of organic compounds.
3 0 These can originate, for example, from the preparation of the zeolite. It is likewise conceivable for alcohols formed in the hydrolysis of metallic esters or substances which are added as described above for promoting the hydrolysis of metallic esters to be present.
3 5 Depending on the moisture content which the mixture is to have for further processing, drying can follow. Here, all conceivable methods can be employed.
Drying of the mixture is preferably corned out simultaneously with spraying in a spray-drying procedure. The spray dryers are preferably operated using inert gases, particularly preferably nitrogen or argon.
In a likewise preferred embodiment of the process of the present invention, 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 structures is mixed in (I) with at least one metal oxide which has a low content of alkali metal and alkaline earth metal ions.
If the zeolite is mixed with two or more metal oxides, it is conceivable for the zeolite to be mixed firstly with the one metal oxide and the resulting mixture to be mixed with a further-metal oxide. If desired, the mixture obtained here can in turn be mixed with a further-metal oxide. It is likewise possible to mix the zeolite with a mixture of two ormore 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.
2 0 Examples of such metal oxides having a low content of alkali metal and alkaline earth metal ions are pyrogenic metal oxides, for example pyrogenic silica.
In the process of the present invention, it is naturally also possible for the mixture resulting from the mixing of the zeolite with the metal oxide to be mixed with at least one metal oxide sol which has, if appropriate, a low content of alkali metal 2 5 and alkaline earth metal ions. With regard to the preparation of this mixture, there are in principle no restrictions, as in the preparation of the mixture of zeolite and metal oxide sol described above. However, preference is given to spraying a suspension comprising the mixture of the zeolite or zeolites and the metal oxide or oxides and the metal oxide sol or sols. There are no restricions in respect of the 3 0 zeolite content of this suspension, as long as, as described above, the processability of the suspension is ensured.
Furthermore, in the process of the present invention it is naturally also possible for a mixture resulting from the mixing of at least one zeolite having an MCM-22, 3 5 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 to be mixed with at least one metal oxide which has, if appropriate, a low content of alkali metal and alkaline _g-earth metal ions. Here, mixing with the metal oxide or oxides can directly follow the preparation of the mixture of the zeolite or zeolites having 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 metal oxide sol or sols. Should, as described above, drying be necessary after the preparation of the mixture of the zeolite or zeolites having 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 metal oxide sol or sols, it is also possible to mix the metal oxide with the dried mixture after drying.
It is likewise possible in the process of the present invention to mix the zeolite or zeolites having an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or -more of these structures simultaneously 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 compounded in a further step of the process of the present invention.
In this compounding or shaping step, fiwther metal oxide can be introduced if desired, using a metal oxide sol prepared as described above as metal oxide source.
This processing step can be carried out in all apparatuses known for this purpose, 2 0 but preference is given to kneaders, pan mills or extruders. A pan mill is particularly preferred for industrial implementation of the process of the present invention.
If, according to one of the above-described embodiments, a mixture of the zeolite 2 5 having an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of these structures and at least one metal oxide is prepared first, this mixture is compounded and a metal oxide sol having a low content of alkali metal and alkaline earth metal ions is additionally added in the compounding step, then, in a preferred embodiment of the present invention, use is made of from 20 to 80%
3 0 by weight of zeolite, from 10 to 60% by weight of metal oxide and from 5 to 30%
by weight of metal oxide sol. Particular preference is given to using 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 metal oxide sol. These percentages are in each case based on the final shaped body produced, as described below.
In a further embodiment of the process of the present invention, the mixing of the zeolite or zeolites having an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or mare of these structures with the metal oxide or oxides which, if appropriate, has/have a low content of alkali metal and alkaline earth metal ions is carried out during the compounding step. It is likewise possible to mix the zeolite or zeolites having an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two ormore of these structures, the metal oxide or oxides and additionally at least one-metal oxide sol in the compounding step.
In this shaping step, it is possible to additionally add one or more viscosity-increasing substances as pasting agents which serve, inter olio, to increase the stability of the uncalcined shaped body, as described below. All suitable substances known from the prior art can be used for this purpose. In the process of the present invention, water or mixtures of water-with one or more organic substances which are miscible with water are used as pasting agent. The pasting agent can be removed again during the later-calcination of the shaped body.
Preference is given to using organic, in particular hydrophilic organic polymers such as cellulose, cellulose derivatives, e.g. methylcellulose, ethylcellulose or hexylcellulose, polyvinylpyrrolidone, ammonium (meth)acrylates, Tylose or mixtures of two or more thereof. Particular preference is given to using 2 0 methylcellulose.
Further additives which can be added are ammonia, amines or amine-like compounds, e.g. tetraalkylammonium compounds or aminoalkoxides. Such further additives are described in EP-A 0 389 041, EP-A 0 200 260 and WO 95/ 19222, 2 5 the full disclosure of which in this respect is hereby incorporated by reference into the present application.
Instead of basic additives, it is also possible to use acidic additives.
Preference is given to acidic organic compounds which can be burnt out by calcination after the 3 0 shaping step. Particular-preference is given to carboxylic acids.
The amount 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 shaped body produced, as described below.
To influence the properties of the shaped body, e.g. transport pore volume, transport pore diameter and transport pore distribution, it is possible to add further substances, preferably organic compounds, in particular organic polymers, as further additives which can also influence the shapeability of the composition.
Such additives include alginates, polyvinylpyrrolidones, starch, cellulose, polyethers, polyesters, polyamides, polyamines, polyimines, polyalkenes, polystyrene, styrene copolymers, polyacrylates, polymethacrylates, fatty acids such as stearic acid, high molecular weight polyalkylene glycols such as polyethylene glycol, polypropylene glycol or polybutylene glycol and mixtures of two or more thereof. The total amount of these substances, based on the final shaped body produced, as described below, is preferably from 0.5 to 10% by weight, particularly preferably from 1 to 6% by weight.
In a preferred embodiment, shaped bodies which are essentially microporous but can additionally have mesopores and/or macropores are produced in the process of the present invention.
The order of addition of the above-described additives to the mixture obtained according to one of the above-described methods is not critical. It is possible either to introduce firstly further metal oxide via metal oxide sol, followed by the viscosity-increasing substances and then the substances which influence the 2 0 transport properties and/or the shapeability of the compounded composition, or to use any other order of addition.
If desired, the generally still pulverulent mixture can be homogenized for from 10 to 180 minutes in the kneader or extruder prior to compounding. This is generally 2 5 carried out in a temperature range from about 10°C to the boiling point of the pasting agent and under atmospheric pressure or slightly superatmospheric pressure. The mixture is kneaded until an extrudable composition has been formed.
The composition which has been compounded and is ready far shaping has, in the 3 0 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, kneading and shaping can be carried out using all conventional 3 5 kneading and shaping apparatuses and methods which are known in large numbers from the prior art and are suitable for the production of, for example, shaped catalyst bodies.
Preference is given to using methods in which shaping is carried out by extrusion in customary extruders, for example to give extrudates having a diameter of usually from about 1 to about 10 mm, in particular from about 1.5 to about 5 mm.
Such extrusion apparatuses are described, for example, in "Ullmanns Enzyklopadie der Technischen Chemie", 4th edition, Volume 2 (1972), pp. 95 ff. Apart from the use of a screw extruder, preference is likewise given to using a ram extruder.
For industrial use of the process, purticular-preference is given to screw extruders.
The extrudates are either rods or honeycombs. The honeycombs can have any shape. They can be, for example, round extrudates, hollow extrudates or star-shaped extrudates. T'he honeycombs can also have any diameter. The external shape and the diameter are generally decided by process engineering requirements for the process in which the shaped body is to be used.
After completion of extrusion, the shaped bodies obtained are dried at generally from 50 to 250°C, preferably from 80 to 250°C, at pressures of generally from 0.01 to 5 bar, preferably from 0.05 to 1.5 bar, for from about 1 to 20 hours.
2 0 Subsequent calcination is carried out at 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 for drying. Calcination is generally carried out in an oxygen-containing atmosphere having an oxygen content of from 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 shaped bodies as described above, in which (I) the zeolite or zeolites having an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of these structures is mixed 3 0 with at least ane 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 from (I), with or without addition of metal oxide sol, is 3 5 compounded;
(III)the composition from (II) is shaped to give a shaped body;
(IV) the shaped body from (III) is dried and (V) the dried shaped body from (IV) is calcined.
A specific embodiment of the invention comprises adding the metal oxide sol to the above-described suspension, drying the resulting suspension, preferably by spray drying, and calcining the resulting powder. The dried and calcined product can then be furrherprocesssed as described in (III).
Of course, the extrudates obtained can be converted into a finished form. All methods of comminution are conceivable here, for example by crushing or breaking the shaped bodies; further chemical treatments, for example as described above, are likewise possible. If comminution takes place, granules or chippings having a particle diameter of from 0.1 to 5 mm, in particular from 0.5 to 2 mm, are preferably produced.
These granules or chippings and also shaped bodies produced in another way contain virtually no material having a particle diameter of less than about 0.1 mm.
As support material for the catalytically active component, namely 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 structures, it is also possible to use all other suitable materials. Examples which may be mentioned are shaped bodies or packing made 2 5 of metal, ceramic or plastics, for instance distillation packing, static mixers, mesh packing or resin beads. 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 structures can be deposited and immobilized on these materials by all conceivable and suitable methods. Such methods are disclosed, for example, in DE-C 42 16 846.5 and DE-3 0 A 196 07 577.7, the full disclosure of which on this subject is hereby incorporated by reference into the present application.
The alkene which is hydrated as described in (i) can in principle come from any suitable source, for example can be prepared by any suitable process. It is possible 3 5 to hydrate, inter alia, alkenes having from 2 to 20 carbon atoms. It is likewise conceivable for the alkenes to be hydrated to have not only at least one C-C
double bond but also further functional groups which may also be able to undergo hydration. Furthermore, alkenes which are substituted in a suitable fashion can be used. Examples of suitable alkenes are:
ethane, propane, 1-butane, 2-butane, isobutene, butadiene, pentanes, piperylene, hexenes, hexadienes, heptenes, octenes, diisobutene, trimethylpentene, nonenes, dodecene, tridecene, tetradecenes to eicosenes, tripropene and tetrapropene, polybutadienes, polyisobutenes, isoprene, terpenes, geraniol, linalool, linalyl acetate, methylenecyclopropane, cyclopentene, cyclohexene, norbornene, cycloheptene, vinylcyclohexane, vinyloxirane, vinylcyclohexene, styrene, cyclooctene, cyclooctadiene, vinylnorbornene, indene, tetrahydroindene, methylstyrene, dicyclopentadiene, divinylbenzene, cyclododecene, cyclododecatriene, stilbene, diphenylbutadiene, vitamin A, beta-carotene, vinylidene fluoride, allyl halides, crotyl chloride, methallyl chloride, dichlorobutene, allyl alcohol, methallyl alcohol, butenols, butenediols, cyclopentenediols, pentenols, octadienols, tridecenols, unsaturated steroids, ethoxyethene, isoeugenol, anethole, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, malefic acid, vinylacetic acid, unsaturated fatty acids such as oleic acid, linoleic acid, palmitic acid, naturally occurring fats and oils.
Particular preference is given to preparing the alkene itself in the process of the present invention from suitable starting materials, with the alkene preferably being prepared from at least one starting material by hydrogenation of this starting material. Preference is given to preparing alkenes having from 2 to 6 carbon atoms 2 5 from at least one starting material, with these alkenes also being able to have more than one C-C double bond. The present invention therefore also provides a process as described above in which (ii) the alkene or alkenes is/are prepared by hydrogenation of at least one 3 0 starting material.
It is possible, inter alia, for the alkene to be prepared by selective hydrogenation of a compound having at least one C-C triple bond. It is likewise possible, starting from a starting material having at least two C-C double bonds, to prepare the 3 5 alkene by selectively hydrogenating at least one C-C double bond of the starting material and leaving at least one C-C double bond in the hydrogenated starting material. Of course, it is also conceivable for starting materials having, for example, at least one C-C double bond and at least ane further functional group capable of hydrogenation to be selectively hydrogenated in such a way that the hydrogenated starting-material has at least one C-C double bond.
Other functional groups capable of hydration other than C-C double bonds can of course also be hydrated in the process of the present invention. Examples which may be mentioned are cyano groups, carboxylic ester groups or carbvxamide groups. As mentioned above, one or-mvre of these functional groups can 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 hydrating cyclic alkenes. In principle, the cyclic alkenes which are preferably used can come from all conceivable sources; they are particularly preferably, as described above, prepared from all suitable starting materials by hydrogenation. In a very particularly preferred embodiment, the present invention provides a process as described above wherein the alkene or alkenes is/are cycloalkene and is/are prepared by selective hydrogenation of benzene as starting material. The selective hydrogenation of benzene can, for example, be corned out by a process 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 alkene or alkenes prepared in this way are carried out in a single step. The term "single step" means, for the purposes of the present application, that the suitable starting material or materials is/are hydrogenated in at 2 5 least one suitable reactor and the alkene prepared in this way is hydrated in the same reactor. The present invention therefore also provides a process as described above 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.
3 0 It is conceivable that, for example, the catalyst or catalysts required for the hydrogenation and the catalyst or catalysts required for the hydration are used in different ways. Here, it is conceivable that, for example, the hydrogenation catalyst or catalysts is/are used as a fixed bed and the hydration catalyst or catalysts is/are used in suspension or the hydrogenation catalyst or catalysts is/are used in 3 5 suspension and the hydration catalyst or catalysts is/are used as a fixed bed or the hydrogenation catalyst or catalysts and the hydration catalyst or catalysts are both used in suspension or as a fixed bed.
In a further embodiment, the process of the present invention is carried out as a reactive distillation. Here, it is conceivable, for example, to use at least one hydrogenation catalyst in, for example, suspension or a fixed bed, while at least one hydrogenation catalyst is applied, for example as a thin layer, to the distillation packing or packings used to separate the organic phase from the aqueous phase.
Likewise, it is of course conceivable for both at least one hydrogenation catalyst and at least one hydration catalyst to be applied as, for example, a thin layer to the distillation packing or packings used for the separation. It is of course also conceivable to use both hydrogenation and hydration catalysts in either suspension or a fixed bed and at the same time to load the distillation packing or packings used with at least one hydration catalyst or both at least one hydration catalyst and at least one hydrogenation catalyst.
It is likewise conceivable for, for example, interior-walls of pipes and/or the reactor which are in contact with compounds to be hydrogenated and/or to be hydrated to be loaded, for example coated, with the appropriate catalyst.
In a preferred embodiment of the process of the present invention, the 2 0 hydrogenation catalyst or catalysts and the hydration catalyst or catalysts are used as a single catalyst system. The present invention therefore also provides a process as described above in which the zeolite having an MCM-22, MCM-36, MCM-49, PSH-3 or TTQ-2 structure or a mixture of two or more of these structures is used as support for at least one catalytically active component used for preparing the 2 5 alkene by hydrogenation of at least one starting material.
Here, it is conceivable, for example, to apply at least one hydrogenation-active component by any suitable method of the prior art to the zeolite having an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or 3 0 more of these structures. The resulting compound can then, for example, be used as such either in a fixed bed or in suspension. It is likewise conceivable to apply the resulting compound, as described above, to the distillation packing or packings used for separating the organic phase from the aqueous phase in the reactive distillation. It is likewise possible to apply the resulting compound to interior walls 3 5 of, for example, the reactor ar pipes, for example in the form of a thin layer. As regards the application of the hydrogenation-active component to the zeolite and the presence of the hydrogenation-active component on the zeolite, reference may be made to DE-A 44 25 672, the full disclosure of which on this subject is hereby incorporated by reference into the present application.
It is likewise conceivable to produce a shaped body in a way described in detail above, in which case at least one hydrogenation-active component is incorporated in addition to 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 structures. Thus, for example, zeolite and hydrogenation-active component can firstly be mixed and subsequently shaped together with metal oxide sol and/or metal oxide by any suitable methods.
It is possible, for example, to subject the mixture of zeolite and hydrogenation-active component together with metal oxide sol to at least one spray-drying step and subsequently, with or without addition of pasting agents, to shape the spray-dried product, with kneaders or pan mills, for example, being able to be used for shaping. It is also conceivable to produce a shaped body as described above from at least zevlite and binder and to apply at least one hydrogenation-active component to the shaped body. These shaped bodies can subsequently be used, for example, in suspension or as a fixed bed in the process of the present invention.
These shaped bodies can also be used, for example, as coatings on distillation 2 0 packing for reactive distillation or on interior walls of the reactor and/or pipes, as described above.
In a further preferred embodiment, the process of the present invention is carried out by carrying out hydrogenation and hydration in at least two different steps. The 2 5 present invention therefore also provides a process as described above 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 a~s described in (ii) using all conceivable 3 0 processes of the prior art, in particular by hydrogenation of at least one suitable starting material using arty conceivable process. There are generally no restrictions in respect of the hydrogenation catalyst or catalysts preferably used here.
After preparation of the alkene, it can be separated by all conceivable and suitable methods from the reaction mixture resulting from (ii) and passed to the hydration 3 5 as described in (i). It goes without saying that the hydrogenation can in principle be carried out in a plurality of stages.
In a further preferred embodiment of the process of the present invention, the reaction mixture formed in the hydrogenation described in (i) is passed without further work-up to the hydration as described in (i).
In a further particularly preferred embodiment of the process, unreacted starting material still present in the reaction product from (ii) is, after the hydration step or steps (i), separated from the reaction product from (i) and is recycled to the hydrogenation as described in (ii). The present invention therefore 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 starting material, (b) the reaction product from (a) comprising the alkene or alkenes and unreacted starting material is passed to a further step (c), (c) the alkene or alkenes is/are hydrated in the presence of water by bringing into contact with at least one heterogeneous catalyst, and 2 0 (d) the unreacted starting material from (a) is separated from the reaction product from (c) and is recycled to (a), wherein the heterogeneous catalyst or catalysts comprises/cvmprise a zeolitic catalyst having an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a 2 5 mixture of two or more of these structures.
In step (a), particular preference is given to preparing cyclic alkenes, especially cyclohexene by selective hydrogenation of benzene. The present invention therefore also provides an integrated process as described above in which the 3 0 alcohol is cyclohexanol, the alkene is cyclohexene and the unreacted starting material which is recycled to (a) is benzene.
In the process of the present invention, it is of course quite generally conceivable for a plurality of alkenes to be prepared in (ii) either simultaneously or in a 3 5 plurality of steps which can also be carried out in different ways. It is likewise conceivable for a plurality of alkenes to be prepared either simultaneously or in a plurality of steps, which may also be carned out in different ways, by hydrogenation of suitable starting materials.
It is also possible to use two or more alkenes in (i), where at least one of these alkenes is com~erted into one alcohol or, depending on the number of C-C
double bonds capable of hydrogenation, a plurality of alcohols.
If the preparation of the alkene or alkenes to be hydrated and the hydration itself are carned out in separate steps, each step can be carned out, depending on the starting materials, in the liquid phase, in the gas phase or in the supercritical phase.
It is likewise conceivable for each step to be carried out 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 quite generally the reaction mixture from the preparation of the alkene or alkenes, water and the catalyst or catalysts having 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 can be fed into the reactor or reactors used for the hydration. For example solvents suitable 2 0 for hydration can be fed into the~hydration reactor or reactors.
The hydration is preferably carried out at from 50 to 250°C and at residence times of the reaction mixture in the reactor-in the range from 0.5 to 8 hours.
2 5 Should the activity of the catalyst having an MCM-22, MCM-36, MCM-49, PSH-or ITQ-2 structure or a mixture of two or more of these structures decrease during the course of the reaction, the present invention provides for it to be regenerated if desired. Thus, for example, it is possible to wash it with a suitable solvent at, if appropriate, elevated temperature or superatmaspheric pressure or at 3 0 superatmospheric pressure and elevated temperature.
In a liquid-phase reaction, possible washing media are, inter alia, oxidizing agents such as oxidizing acids or peroxide solutions, e.g. hydrogen peroxide. In the supercritical phase, it is also possible to use, for example, carbon dioxide as 3 5 washing medium. Likewise, the catalyst to be regenerated can be treated at increased temperature and/or increased pressure with a suitable gas mixture which is able to increase the activity of the deactivated catalyst. Here, preference is given to using, for example, oxygen-contairring gases or gases which can liberate oxygen under the regeneration conditions chosen. Examples which may be mentioned are nitrogen oxides, preferably N20.
All the abovementioned regeneration procedures can be carried out while the catalyst is installed in the reactor or else outside the reactor after the catalyst has been taken out. It is of course also possible to regenerate the catalyst a number of times. The present invention therefore also provides a process or an integrated process as described above wherein the zeolitic catalyst or catalysts is/are regenerated at least once and is/are reused in the process.
For the regeneration of the catalyst used according to the present invention, it is in principle preferable to use all methods known from the prior art for the regeneration of silicate-containing catalysts, in particular zeolite catalysts. The deactivated catalyst is generally treated at 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 higher than that of the deactivated catalyst.
Specific mention may be made by way of example of the following processes:
2.0 1. a process for regenerating a deactivated (zeolite) catalyst, which comprises heating the deactivated catalyst at a temperature of less than 400°C
but higher than 150°C in the presence of molecular oxygen for a period which is sufficient to increase the activity of the deactivated catalyst, as is 2 5 described in EP-A 0 743 094;
2. a process for regenerating a deactivated (zeolite) catalyst, which comprises heating the deactivated catalyst at from 150°C to 700°C in the presence of a gas stream containing no more than 5% by volume of molecular oxygen for 3 0 a period which is sufficient to improve the activity of the deactivated catalyst, as is described in EP-A 0 790 075;
3. a process for regenerating (zeolite) catalysts, in which the deactivated catalyst is heated at from 400 to 500°C in the presence of an oxygen-3 5 containing gas or is washed with a solvent, preferably at a temperature which is from 5°C to 150°C higher than the temperature used during the reaction, as is described in JP-A 3 11 45 36;
4. a process for regenerating a deactivated (zeolite) catalyst by calcining it at 550°C in air or by washing with solvents, so that the activity of the catalyst is restored, as described in Proc. 7th Intern. Zeolite Conf. 1986 (Tokyo);
5. a process for regenerating a (zeolite) catalyst, which comprises steps (A) and (B) below:
(A) heating an at least partially deactivated catalyst to a temperature in the range from 250°C to 600°C in an 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 gas stream having a content of an oxygen-releasing substance or oxygen or a mixture of two or more thereof in the range from 0.1 to 4% by volume, where the process may also comprise the further steps (C) and (D), 2 0 (C) treating the catalyst at a temperature in the range from 250 to 800°C, preferably from 350 to 600°C, with a gas stream having a content of an oxygen-releasing substance or oxygen or a mixture of two or more thereof in the range from > 4 to 100% by volume, 2 5 (D) cooling the regenerated catalyst obtained in step (C) in an inert gas stream containing up to 20% by volume of a liquid vapor selected from the group consisting of water, alcohols, aldehydes, ketones, ethers, acids, esters, nitrites, hydrocarbons and mixtures of two or more thereof.
Details of this process may be found in DE-A 197 23 949.8.
Furthermore, it is likewise conceivable for the catalyst to be regenerated by washing with at least one hydrogen peroxide solution or with one or more 3 5 oxidizing acids. Of course, the above-described methods can be combined with one another in a suitable fashion.
If hydrogenation-active components such as metals are applied to the zeolitic catalyst, as is described above for a preferred embodiment of the present invention, it is possible for these to be detached from the zeolite and reused for a renewed catalyst preparation step.
For the purposes of the present invention, it is of course also conceivable for the regenerated catalyst to be used in another process.
The invention is illustrated by the following examples.
Ezamples:
Example 1: Preparation of MCM-22 In a stirred apparatus, 8.3 g of sodium aluminate (43.6% of Na20, 56.8% A1203) and 5.3 g of NaOH flakes were dissolved in 200 g of deionized water. A
sulfuric acid solution consisting of 1 g of HZS04 (98% by weight) in 50 g of water was added to the above solution. T'he resulting solution was added while stirring to a suspension of 88 g of pyrogenic silica (Aerosil 200) in 850 g of water. 48 g of 2 0 hexamethyleneimine were subsequently added and the mixture was homogenized for 30 minutes. The mixture was reacted at 150°C for 288 hours, the solid was filtered off and washed three times with 100 ml of water. It was subsequently dried at 120°C and calcined at 500°C in air for 5 hours. 'The product displayed an X-ray diffraction pattern typical for MCM-22 and, according to wet chemical analysis, had the following composition: 38.0% by weight of Si, 1.9% by weight of Al and 1.2% by weight of Na. T'he specific surface area determined by the Langmuir method using N2 at 77 K was 639 m2/g. The material was converted into 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 3 5 In a 50 ml capacity glass pressure autoclave, 3 g of the catalsyt from Example 1 were reacted with 0.092 mol of benzene (reaction product from the hydrogenation of benzene to cyclohexene), 0.022 mol of cyclohexene and 0.2 mol of water at 120°C for 5 hours while stirring. The resulting phase mixture was homogenized after the reaction by addition of dimetlrylformarnide/methanol and analyzed by means of GC.
The yield of cyclohexanol based on cyclohexene used was 9.2 mol%.
Example 3 : Comparative example using [3-zeolite for the hydration In a 50 ml capacity glass pressure autoclave, 3 g of ~-zeolite in the H form were reacted with 0.092 mol of benzene, 0.022 mol of cyclohexene and 0.2 mol of water at 120°C for 5 hours while stirring. 'The resulting phase mixture was homogenized after the reaction by addition of dimethylformamide/methanol and analyzed by means of GC. The yield of cyclohexanol based an cyclohexene used was only 7.5 mol%.
Claims (9)
1. A process for-preparing cyclohexanol, in which (i) cyclohexene is hydrated in the presence of water by the bringing into contact with at least one catalyst to form cyclohexanol, wherein the heterogeneous catalyst or catalysts comprises/comprise a zeolitic catalyst having an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of these structures.
2. A process as claimed in claim 1, wherein the zeolitic catalyst or catalysts comprises/comprise at least one element of transition group I, II or VIII of the Periodic Table.
3. A process as claimed in claim 1 or 2, in which (ii) cyclohexene is prepared by hydrogenation of at least one starting material.
4. A process as claimed in any of claims 1 to 3, wherein cyclohexene is prepared by selective hydrogenation of benzene as starting material.
5. A 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.
6. A process as claimed in claim 5, wherein the zeolitic catalyst having 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 support for at least one catalytically active component which is used for preparing cyclohexene by hydrogenation of benzene.
7. A 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.
8. An integrated process for preparing cyclohexene, in which (a) cyclohexene is prepared by hydrogenation of benzene, (b) the reaction product from (a) comprising cyclohexene and unreacted starting material is passed to a further step (c), (c) cyclohexene is hydrated in the presence of water by bringing into contact with at least one heterogeneous catalyst, and (d) the unreacted starting material from (a) is separated from the reaction product from (c) and is recycled to (a), wherein the heterogeneous catalyst or catalysts comprises/comprise a zeolitic catalyst having an MCM-22, MCM-36, MCM-49, PSH-3 or ITQ-2 structure or a mixture of two or more of these structures.
9. A process as claimed in any of claims 1 to 8, wherein the zeolitic catalyst or catalysts is/are regenerated at least once and is/are reused in the process.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19951280.9 | 1999-10-25 | ||
| DE19951280A DE19951280A1 (en) | 1999-10-25 | 1999-10-25 | Alcohol preparation comprises hydrating an alkene(s) using water and a catalyst(s) comprising a zeolite catalyst of specified structure |
| PCT/EP2000/010469 WO2001030730A1 (en) | 1999-10-25 | 2000-10-24 | Method for producing an alcohol from an alkene |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2388881A1 true CA2388881A1 (en) | 2001-05-03 |
Family
ID=7926748
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002388881A Abandoned CA2388881A1 (en) | 1999-10-25 | 2000-10-24 | Method for producing an alcohol from an alkene |
Country Status (11)
| Country | Link |
|---|---|
| EP (1) | EP1226101A1 (en) |
| JP (1) | JP2003512444A (en) |
| KR (1) | KR20020044173A (en) |
| CN (1) | CN1399621A (en) |
| AR (1) | AR026210A1 (en) |
| AU (1) | AU1144301A (en) |
| CA (1) | CA2388881A1 (en) |
| CO (1) | CO5231216A1 (en) |
| DE (1) | DE19951280A1 (en) |
| MX (1) | MXPA02004070A (en) |
| WO (1) | WO2001030730A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6943274B2 (en) | 2002-03-06 | 2005-09-13 | Basf Aktiengesellschaft | Method for the production of cyclohexanol from benzene |
| WO2009003026A3 (en) * | 2007-06-27 | 2009-02-19 | H R D Corp | Method of making alcohols |
| US8217205B2 (en) | 2007-06-27 | 2012-07-10 | H R D Corporation | Method of making alcohols |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60104028A (en) * | 1983-11-09 | 1985-06-08 | Asahi Chem Ind Co Ltd | Production of cyclic alcohol |
| JP2754063B2 (en) * | 1988-11-28 | 1998-05-20 | モービル オイル コーポレーシヨン | Synthetic porous crystalline material, its synthesis and use |
| US5071627A (en) * | 1989-12-04 | 1991-12-10 | Mobil Oil Corp. | Reactor system for conducting a chemical conversion |
| US5231233A (en) * | 1992-05-04 | 1993-07-27 | Mobil Oil Corp. | Process for the hydration of olefins |
| US5488186A (en) * | 1995-03-22 | 1996-01-30 | Mobil Oil Corporation | Gas phase process for the hydration of propylene |
-
1999
- 1999-10-25 DE DE19951280A patent/DE19951280A1/en not_active Withdrawn
-
2000
- 2000-10-23 AR ARP000105567A patent/AR026210A1/en unknown
- 2000-10-24 CA CA002388881A patent/CA2388881A1/en not_active Abandoned
- 2000-10-24 WO PCT/EP2000/010469 patent/WO2001030730A1/en not_active Application Discontinuation
- 2000-10-24 AU AU11443/01A patent/AU1144301A/en not_active Abandoned
- 2000-10-24 CN CN00816247A patent/CN1399621A/en active Pending
- 2000-10-24 EP EP00972857A patent/EP1226101A1/en not_active Withdrawn
- 2000-10-24 JP JP2001533088A patent/JP2003512444A/en not_active Withdrawn
- 2000-10-24 MX MXPA02004070A patent/MXPA02004070A/en not_active Application Discontinuation
- 2000-10-24 KR KR1020027005315A patent/KR20020044173A/en not_active Application Discontinuation
- 2000-10-25 CO CO00081379A patent/CO5231216A1/en unknown
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6943274B2 (en) | 2002-03-06 | 2005-09-13 | Basf Aktiengesellschaft | Method for the production of cyclohexanol from benzene |
| WO2009003026A3 (en) * | 2007-06-27 | 2009-02-19 | H R D Corp | Method of making alcohols |
| US7910068B2 (en) | 2007-06-27 | 2011-03-22 | H R D Corporation | Method of making alcohols |
| US8217205B2 (en) | 2007-06-27 | 2012-07-10 | H R D Corporation | Method of making alcohols |
| US8329962B2 (en) | 2007-06-27 | 2012-12-11 | H R D Corporation | Method of making alcohols |
| US8461400B2 (en) | 2007-06-27 | 2013-06-11 | H R D Corporation | Method of making alcohols |
| EA020291B1 (en) * | 2007-06-27 | 2014-10-30 | ЭйчАДи КОПЭРЕЙШН | Method and system of olefin hydration |
Also Published As
| Publication number | Publication date |
|---|---|
| EP1226101A1 (en) | 2002-07-31 |
| AU1144301A (en) | 2001-05-08 |
| DE19951280A1 (en) | 2001-04-26 |
| KR20020044173A (en) | 2002-06-14 |
| AR026210A1 (en) | 2003-01-29 |
| CO5231216A1 (en) | 2002-12-27 |
| CN1399621A (en) | 2003-02-26 |
| MXPA02004070A (en) | 2002-10-11 |
| JP2003512444A (en) | 2003-04-02 |
| WO2001030730A1 (en) | 2001-05-03 |
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