EP1996322A1

EP1996322A1 - Mixed oxide catalysts

Info

Publication number: EP1996322A1
Application number: EP07726607A
Authority: EP
Inventors: Martin Ernst; Thilo Hahn; Johann-Peter Melder
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2006-03-10
Filing date: 2007-03-02
Publication date: 2008-12-03
Also published as: RU2434676C2; WO2007104663A1; RU2008140041A; RU2434676C9; CN101400442A; US20090149314A1; JP2009529419A; CN101400442B

Abstract

Catalysts which are prepared by reduction of catalyst precursors and comprise a) cobalt and b) one or more elements of the alkali metal group, the alkaline earth metal group, the group of the rare earths or zinc or mixtures thereof, the elements a) and b) being present at least partly in the form of their mixed oxides, and a process for preparing these catalysts and their use for hydrogenating unsaturated organic compounds. Furthermore, a process is described for regenerating these catalysts by treating the catalyst with a liquid.

Description

Mixed oxide catalysts

description

The present invention relates to catalysts prepared by reduction of catalyst precursors containing a) cobalt and b) one or more elements of the alkali metal group, the alkaline earth metal group, the rare earth element or zinc or mixtures thereof, wherein elements a) and b ) are present at least partly in the form of their mixed oxides. Furthermore, the present invention relates to processes for the preparation of these catalysts and their use for hydrogenation. The present invention also relates to a process for the regeneration of these catalysts.

Further embodiments of the invention can be taken from the claims, the description and the examples. It is understood that the above-mentioned and below to be explained features of the subject invention can be used not only in the combination given but also in other combinations, without departing from the scope of the invention. Cobalt catalysts are generally prepared by calcination and reduction of catalyst precursors, such as cobalt hydroxide, cobalt nitrate and cobalt oxide, or in the form of cobalt sponge catalysts (Raney cobalt) in hydrogenation reactions.

The hydrogenation of organic nitriles with Raney catalysts is frequently carried out in the presence of basic alkali metal or alkaline earth metal compounds, as described in US Pat. Nos. 3,821,305, 5,874,625, 5,151,543, 4,375,003, EP-A-0316761, EP-A A-0913388 and US 6,660,887.

Cobalt-containing catalysts can furthermore be prepared by reducing cobalt oxide, cobalt hydroxide or cobalt carbonate. In DE-OS-3403377 catalysts are described which contain metallic cobalt and / or nickel particles which are obtainable from cobalt and / or nickel oxide particles by contact with hydrogen. According to this disclosure, the content of alkali and / or alkaline earth is advantageously less than 0.1% by weight. EP-B-0742045 describes cobalt catalysts obtained by calcination of the oxides of the elements cobalt (55-98% by weight), phosphorus (0.2 to 15% by weight), manganese (0.2 to 15% by weight) Wt .-%) and alkali (0.05 to 5 wt .-%) and subsequent reduction in the hydrogen stream are produced. Cobalt catalysts obtainable by precipitation of cobalt carbonate from an aqueous solution of a cobalt salt and subsequent reduction with hydrogen are set forth in EP-A-0 322 760. In addition, these catalysts may contain 0.25 to 15% by weight, based on the total mass of catalyst, SiO 2, MnO 2, ZrO 2, Al 2 O 3 and MgO in the form of the oxides, hydroxides or oxide hydrates. hydrogenation catalysts, which consist of one or more oxides of the elements Fe, Ni, Mn, Cr, Mo, W and P and one or more oxides of the alkali, alkaline earth and the rare earth group are described in EP-BO 445,589. Apparently, the oxides after reduction are partially present as metals.

By means of this invention, improved hydrogenation catalysts should be provided which offer advantages over conventional processes. Thus, the smallest possible amounts of metals, such as. As aluminum in the case of skeletal catalysts or alkaline promoters such as lithium, dissolve out of the catalyst, as this leads to decreasing stability and deactivation of the catalyst. Aluminates, which form from the dissolved aluminum under basic conditions, can lead to blockages and deposits as solid residues and cause the decomposition of desired product. Another object of the present invention was to find catalysts which allow the hydrogenation of organic compounds under simplified reaction conditions. Thus, catalysts should be found which allow the hydrogenation reaction to be carried out at lower pressures. Furthermore, hydrogenation processes should be accessible, which can be carried out in the absence of water, ammonia and aqueous base.

It was also an object of this invention to provide a hydrogenation process which allows hydrogenation of nitriles to primary amines with high selectivity. Accordingly, the catalysts described above were found.

According to the invention, the catalyst is obtainable by using a catalyst precursor comprising a) cobalt and b) one or more elements of the alkali metal group, the alkaline earth metal group, the rare earth group or zinc or mixtures thereof, wherein the elements a) and b) at least in part in the form of their mixed oxides, reduced.

A mixed oxide is characterized in that the crystal lattice in addition to cobalt and oxygen at least one further element b) from the group alkali or alkaline earth metals or the group of rare earths or zinc. Thus, b) lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, barium, radium, scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, Holmium, erbium, thulium, ytterbium or zinc, preferably lithium, sodium, potassium, magnesium, calcium or zinc or a mixture of two or more of said elements. According to the proportions of cobalt to the element b), can

1. element b) occupy a lattice site (substitution mixed crystal) or an interstitial site (intercalation crystal) instead of cobalt,

2. cobalt instead of element b) occupy a lattice site or an interstitial space, or

3. Cobalt and the element b) with oxygen form a common crystal lattice, which does not resemble any of the basic compounds.

Explicitly referred to as "solid solutions", ie continuous series of mixed crystals, are also included in the description of mixed oxide A mixture of oxides or an oxide mixture differs from the mixed oxide present according to the invention in that in the case of a mixture of oxides or oxides The fact that the mixed oxide according to the invention is present can be detected analytically, for example by means of X-ray diffractometry, in which the crystal structures of the cobalt oxide and of the oxides of the elements b) are present next to one another in comparison with reference spectra in crystallographic databases [ICSD (Inorganic Crystal Structure Database), Bergerhoff et al, University of Bonn (D) or Powder Diffraction File, Berry et al., International Center for Diffraction Data (ICDD), Swarthmore (USA)] The catalyst precursors for the preparation of erfindungsmäßen catalysts we used As explained above, some of them are present as mixed oxide containing cobalt and at least one of the elements b) listed above. Preferably, the catalyst precursors are partly as mixed oxides of Co and Li, as mixed oxides of Co and Na, as mixed oxides of Co and K, as mixed oxides of Co and Rb, as mixed oxides of Co and Cs, as mixed oxides of Co and Be, as mixed oxides of Co and Mg, as mixed oxides of Co and Ca, as mixed oxides of Co and Sr, as mixed oxides of Co and Ba, as mixed oxides of Co and La, as mixed oxides of Co and Y and as mixed oxides of Co and Zn. More preferably, the catalyst precursors are present in part as mixed oxides of Co and Li, as mixed oxides of Co and Mg, and as mixed oxides of Co and Zn, and most preferably the catalyst precursors are partly mixed oxides of Co and Li and mixed oxides of Co and Mg in front. In a further preferred embodiment, the catalyst precursors which are used for the preparation of the catalysts of the invention, partly as mixed oxides of Li, Na and Co, as mixed oxides of Li, K and Co, as mixed oxides of Li, Mg and Co, as mixed oxides of Li, Ca and Co, as mixed oxides of Na, Mg and Co, as mixed oxides of K, Mg and Co, as mixed oxides of Na, Ca and Co and as mixed oxides of K, Ca and Co.

In a preferred embodiment, catalyst precursors can be reduced which contain one or more compounds of the empirical formula where x = 0 or x = 0.1 to 1, y = 0 or y = 0.1 to 1 and z = 0.1 to 1, and x and y do not coincide may be zero, and M ^{1 is} at least one element of the alkali metal group and M "is at least one element of the alkaline earth metal group or zinc Most preferred is the catalyst precursor having the empirical formula LiCoO 2 (lithium cobaltite) LiCoO 2 may be in the form of the cryogenic phase (LT -LiCoθ2), the high-temperature phase (HT-UCOO2) or as a mixture of both.

In a further preferred embodiment, the catalyst precursor used is lithium cobaltite, which is obtained by the recycling of batteries. Furthermore, continuous mixed crystal series of Co oxide and Mg oxide with the formula Mg _a CO 2 bOi are suitable as catalyst precursors, where 0 <a <1 and 0 <b <1 and a + b = 1. The catalyst precursors according to the invention are present partly in the form of their mixed oxides. However, the catalyst precursors can also be present exclusively in the form of their mixed oxides. The proportion of cobalt in the catalyst precursor present in the form of mixed oxides is preferably at least 10 mol%, advantageously at least 20 mol% and particularly preferably at least 30 mol%, in each case based on the total cobalt present in the catalyst precursor. It is also possible that the catalyst precursor contains one or more additional components in addition to one or more mixed oxides. As additional components elemental oxides may be included. As element oxides, oxides of the elements of the first to fifth main group or oxides of the elements of the third to eighth subgroup may be suitable, in particular oxides of the elements Co, Ni, Cu, Mn, P, Cr, Ag, Fe, Zr, Al, Ti , Li, Na, K, Mg, Ca, Zr, La or Y.

The catalyst precursor may contain one or more dopants. Suitable doping elements are the elements of the 3rd to 8th subgroup of the Periodic Table of the Elements (in the version of 03.10.2005 of IUPAC

(http://www.iupac.org/reports/periodic_table/IUPAC_Periodic_Table-3Oct05.pdf)), as well as the elements of the third, fourth and fifth main groups. Preferred dopants are Fe, Ni, Cr, Mn, P, Ti, Nb, V, Cu, Ag, Pd, Pt, Rh, Ir, Ru and Au. The doping elements are preferably present in amounts of not more than 10% by weight, for example from 0.1 to 10% by weight, more preferably in amounts of from 1 to 5% by weight, in each case based on the catalyst precursor used.

Catalyst precursors can generally be obtained by thermal treatment of the corresponding compounds of cobalt and one or more compounds of the alkali metal group, compounds of the alkaline earth metal group, compounds of the rare earth group or compounds of zinc, for example the nitrates, carbonates, hydroxides, oxides , Acetates, oxalates or citrates. Thermal treatment may be understood, for example, as the fusing or calcination of the above compounds. In this case, the thermal treatment of the abovementioned compounds, such as the nitrates, carbonates, hydroxides, oxides, can be carried out in air. In a preferred embodiment, the thermal treatment, in particular of the carbonates, takes place under an inert gas stream. The atmosphere. Suitable inert gases include, for example, nitrogen, carbon dioxide, helium, neon, argon, xenon, krypton or mixtures of said inert gases. Preferably, nitrogen is suitable. The preparation of the catalyst precursors by thermal treatment of the abovementioned compounds under an inert gas atmosphere has the advantage that the subsequent reduction of the catalyst precursor can be connected directly to the thermal treatment described above. If the catalyst precursor is not prepared under an inert gas atmosphere, an additional inerting step should be carried out prior to reduction. In the inerting step, interfering compounds, such as atmospheric oxygen, which can react with the reducing agent in the reduction, for example by gassing the catalyst precursor with inert gas or by repeated evacuation and venting with inert gas can be removed.

Another method of preparing the catalyst precursors is to precipitate water-soluble cobalt compounds and at least one or more of water-soluble alkali compounds, water-soluble alkaline earth compounds, water-soluble rare earth compounds and water-soluble zinc compounds, by adding an alkaline solution and then drying calcination.

Methods of producing LiCoO 2 are e.g. in Antolini [E. Antolini, Solid State Ionics, 159-171 (2004)] and Fenton et al. [W. M. Fenton, P.A. Huppert, Sheet Metal Industries, 25 (1948), 2255-2259).

Thus, LiCoO 2 can be prepared by thermal treatment of the corresponding lithium and cobalt compounds, such as nitrates, carbonates, hydroxides, oxides, acetates, citrates or oxalates.

Further, LiCoO 2 can be precipitated by precipitating water-soluble lithium and cobalt salts by adding an alkaline solution, followed by calcination.

LiCoO 2 can also be obtained by the sol-gel method.

LiCoO 2 may also be prepared as described by Song et al. [S. W. Song, K.S. Han, M. Yoshimura, Y. Sata, A. Tatsuhiro, Mat. Res. Soc. Proc., 606, 205-210 (2000)], by hydrothermal treatment of cobalt metal with LiOH aqueous solutions.

According to the invention can also be used as a catalyst precursor LiCoθ2, which is obtained by the reprocessing of batteries. A method for recycling or recovering lithium cobaltite from waste batteries can be derived, for example, from CN 1594109. By mechanically opening the battery terie and the extraction of aluminum components with conc. NaOH, a Li-Coθ2-rich filter cake can be obtained.

After the synthesis of the oxidic catalyst precursor, a washing step or a washing step with subsequent drying may follow before the reduction. The wash step removes impurities, by-products or unreacted starting materials.

The catalyst precursor may, as previously described, contain one or more dopants.

These dopants can be incorporated by the addition of metal complexes and metal salts such as metal carbonates and metal oxides, or the metals themselves in the preparation of the catalyst precursor by fusing together the corresponding oxides or carbonates or mixtures thereof. Likewise, during the production, the dopants can be introduced via a precipitation reaction as water-soluble salts and complexes which are mixed with a precipitation reagent. Furthermore, it is possible to superficially dope the oxidic catalyst precursor with metal salts prior to reduction by dissolving them over a period of time, e.g. be brought into contact with the mixed oxide in aqueous solution. Even after the reduction of the catalyst precursor and even during the hydrogenation reaction, the catalyst already prepared by the reduction of a catalyst precursor can still be doped in the same way. In this case, the catalyst precursor and / or the catalyst may already be doped with doping elements.

The catalyst precursor generally obtained in powder form can be subjected to shaping before the reduction or can be absorbed (supported) on porous and surface-active materials. Common methods of shaping and carrying are described, for example, in Ullmann [Ullmann's Encyclopedia Electronic Release 2000, Chapter: 'Catalysis and Catalysts', S28-32]. Likewise, suitable substances can be applied to a support and reacted there, the catalyst precursor being formed.

The reduction of the catalyst precursor can be carried out in a liquid in which the catalyst precursor is suspended. The reduction in the liquid may be e.g. in a stirred autoclave, a packed bubble column, a circulation reactor or a fixed bed reactor.

The reduction can also be carried out dry as a powder in a moving or stationary reduction furnace or in a fixed bed or in a fluidized bed. In a preferred embodiment, the reduction of the catalyst precursor is carried out in a liquid in which the catalyst precursor is suspended. Suitable liquids for suspending the catalyst precursor are water or organic solvents, for example ethers such as methyl tert-butyl ether, ethyl tert-butyl ether or tetrahydrofuran (THF), alcohols such as methanol, ethanol or isopropanol, hydrocarbons such as hexane, heptane or Raffinatschnitte, aromatics such as toluene or amides such as dimethylformamide or dimethylacetamide or lactams, such as N-

Methylpyrrolidone, N-ethylpryrrolidone, N-methylcaprolactam or N-ethylcaprolactam. Suitable liquids are also suitable mixtures of the abovementioned solvents.

Preferred liquids contain products from the hydrogenation to be carried out. Particular preference is given to liquids which are the product of the hydrogenation to be carried out.

In a further preferred variant, the catalyst precursor is suspended in a liquid which contains no water.

In the reduction of the catalyst precursor in suspension, the temperatures are generally in a range from 50 to 300 ° C, in particular from 100 to 250 ° C, particularly preferably from 120 to 200 ° C.

The reduction in suspension is generally carried out at a pressure of 1 to 300 bar, preferably from 10 to 250 bar, more preferably from 30 to 200 bar, wherein the pressure data here and below relate to the absolute measured pressure. Suitable reducing agents are hydrogen or a hydrogen-containing gas or a source of hydride ions.

The hydrogen is generally used technically pure. The hydrogen may also be in the form of a hydrogen-containing gas, i. in admixtures with other inert gases, such as nitrogen, helium, neon, argon or carbon dioxide. The hydrogen stream can also be recycled as recycle gas into the reduction, possibly mixed with fresh hydrogen and, if appropriate, after removal of water by condensation.

The reduction of the dry, usually powdered catalyst precursor can be carried out at elevated temperature in a moving or stationary reduction furnace. The reduction of the catalyst precursor is generally carried out at reduction temperatures of 50 to 600 ° C, in particular from 100 to 500 ° C, particularly preferably from 150 to 400 ° C.

The operating pressure is generally from 1 to 300 bar, in particular from 1 to 200 bar, more preferably from 1 to 10 bar, wherein a stream of hydrogen or a hydrogen-containing stream, as described above still admixing of others Inert gases may be passed through or over the catalyst bed. Also in this embodiment, the hydrogen stream can be recycled as recycle gas in the reduction, optionally mixed with fresh hydrogen and optionally after removal of water by condensation.

The reduction is preferably carried out so that the degree of reduction is at least 50%. As a method of measuring the degree of reduction, a comparison is made of the dry-reduced catalyst dry-catalyst-precursor mass decrease, which reduces these samples from room temperature to 900 ° C in a hydrogen-containing gas stream, recording the integral of the mass decrease. The degree of reduction is calculated from the ratio of weight decreases as follows: Degree of reduction [%] = 100 ^* (1- (Weight Loss Reduced Catalyst / Weight ReductionTieoxidic Precursor))

During the reduction, a solvent may be supplied to remove the resulting reaction water. The solvent can also be supplied supercritically.

Suitable solvents may be the same as those described above for suspending the catalyst. Preferred solvents are ethers such as methyl tert-butyl ether, ethyl tert-butyl ether or tetrahydrofuran, alcohols such as methanol, ethanol or isopropanol, hydrocarbons such as hexane, heptane or Raffinatschnitte, aromatics such as toluene or amides such as dimethylformamide or dimethylacetamide or lactams such as N-methylpyrrolidone, N-ethylpyrrolidone , N-methylcaprolactam or N-ethylcaprolactam. Particularly preferred are methanol or tetrahydrofuran. Suitable suitable solvents are also suitable mixtures. The above-mentioned reaction conditions for the reduction of the catalyst precursor generally apply, eg for stirred autoclave, fluidized bed or fixed bed process. The catalyst of the invention may also be prepared by reduction with a source of hydride ion in a solvent starting from the catalyst precursor. Suitable hydride ion sources are complex hydrides such as LiAlH ₄ or NaBH ₄ . Suitable solvents are ethers such as methyl tert-butyl ether, ethyl tert-butyl ether or tetrahydrofuran, hydrocarbons such as hexane, heptane or Raffinatschnitte or aromatics such as toluene. Particularly preferred is tetrahydrofuran. Suitable suitable solvents are also suitable mixtures.

When using a source of hydride ion reduction is preferably carried out at temperatures of 10-200 ⁰ C at the appropriate system pressure.

The reduction of the catalyst precursor may preferably be carried out to a degree of reduction of 50 to 100%. The catalyst may be handled and stored after reduction under an inert gas such as nitrogen or under an inert liquid, for example an alcohol, water or the product of the particular reaction for which the catalyst is employed. After the reduction, however, the catalyst can also be passivated with nitrogen with an oxygen-containing gas stream such as air or a mixture of air with nitrogen, ie provided with a protective oxide layer.

The term catalyst refers hereinafter to a catalyst which has been prepared according to the invention by reduction of the catalyst precursor described or a catalyst which has been passivated as described above after activation with an oxygen-containing gas stream.

The storage of the catalyst under inert substances or the passivation of the catalyst allow uncomplicated and safe handling and storage of the catalyst. If appropriate, the catalyst must then be freed of the inert liquid before the actual reaction or the passivation layer z. B. be lifted by treatment with hydrogen or a gas containing hydrogen.

The catalysts of the invention can be used in a process for the hydrogenation of compounds containing at least one unsaturated carbon-carbon, carbon-nitrogen or carbon-oxygen bond or the partial or complete nuclear hydrogenation of compounds containing aromatics.

Suitable compounds are generally compounds which contain at least one or more carboxylic acid amide groups, nitrile groups, imine groups, enamine groups, azine groups or oxime groups which are hydrogenated to give amines. Furthermore, in the process according to the invention, compounds containing at least one or more carboxylic acid ester groups, carboxylic acid groups, aldehyde groups or keto groups which are hydrogenated to alcohols can be hydrogenated. Suitable compounds are also aromatics, which can be converted to unsaturated or saturated carbo-or heterocycles. Particularly suitable compounds which can be used in the process according to the invention are organic nitrile compounds. These can be hydrogenated to primary amines.

Suitable nitriles are acetonitrile for the preparation of ethylamine, propionitrile for the preparation of propylamine, butyronitrile for the preparation of butylamine, lauronitrile for the preparation of laurylamine, stearyl nitrile for the preparation of stearylamine, N ₁ N-

Dimethylaminopropionitrile (DMAPN) for the preparation of N, N-dimethylaminopropylamine (DMAPA) and benzonitrile for the preparation of benzylamine. Suitable dinitriles are adi podinitrile (ADN) for the preparation of hexamethylenediamine (HMD) and / or amino capronitrile (ACN), 2-methylglutarodinitrile for the preparation of 2-methylglutarodiamine, succinonitrile for the preparation of 1, 4-butanediamine and suberonitrile for the preparation of octamethylenediamine. Also suitable are cyclic nitriles, such as isophorone nitrile (isophorone nitrile) for the preparation of isophorone diamine and isophthalonitrile for the preparation of meta-xylylenediamine. Also suitable are α-aminonitriles and β-aminonitriles, such as aminopropionitrile for the preparation of 1, 3-diaminopropane or ω-aminonitriles, such as aminocapronitrile for the preparation of hexamethylenediamine. Further suitable compounds are so-called "Strecker nitriles", such as iminodiacetonitrile for the production of diethylenetriamine, Dinitrotoluene is also suitable for the preparation of toluidine diamine Further suitable nitriles are β-aminonitriles, for example addition products of alkylamines, alkyldiamines or alkanolamines and acrylonitrile For example, 3- [2-aminoethyl) amino] propionitrile can be converted into 3- (2-aminoethyl) aminopropylamine and 3,3 '- (ethylenediimino) bispropionitrile or 3- [2-] ethylenediamine and acrylonitrile to give the corresponding diamines. (3-Amino-propylamino) ethylamino] -propionitrile to N, N'-bis (3-aminopropyl) ethylenediamine.

Particular preference is given to using N, N-dimethylaminopropionitrile (DMAPN) for the preparation of N, N-dimethylaminopropylamine (DMAPA) and adiponitrile (ADN) for preparing hexamethylenediamine (HMD) in the process according to the invention.

As the reducing agent, hydrogen, a hydrogen-containing gas or a hydride ion source can be used.

The hydrogen used for the hydrogenation is generally used in the larger stoichiometric excess of from 1 to 25 times, preferably from 2 to 10 times or stoichiometric amounts. It can be recycled as recycle gas into the reaction. The hydrogen is generally used technically pure. The hydrogen may also be in the form of a hydrogen-containing gas, i. in admixtures with other inert gases, such as nitrogen, helium, neon, argon or carbon dioxide are used.

The hydrogenation can also be carried out with a hydride ion source. Suitable hydride ion sources are complex hydrides such as LiAlH ₄ or NaBH ₄

In a process for the preparation of amines by reduction of nitriles, the hydrogenation can be carried out with the addition of ammonia. As a rule, ammonia is used in molar ratios to the nitrile group in the ratio of 0.5: 1 to 100: 1, preferably 2: 1 to 20: 1. The preferred embodiment is a method in which no ammonia is added. The hydrogenation can be carried out in the presence of a liquid. The liquid may be the same liquid in which, as previously described, the catalyst precursor has been reduced or suspended.

Suitable liquids are, for example, C 1 - to C ₄ -alcohols, C 1 - to C 12 -dialkyl ethers or cyclic C ₄ - to C 12 -ethers, such as tetrahydrofuran or tert-butylmethyl ether. Suitable liquids may also be mixtures of the abovementioned liquids. The liquid may also be the product of the hydrogenation. In a preferred embodiment, the hydrogenation is carried out in an anhydrous liquid.

The catalyst can be freed from the inert liquid or passivation layer before starting the hydrogenation. This happens, for example, by treatment with hydrogen or a gas containing hydrogen. Preferably, the hydrogenation is carried out directly after the reduction of the catalyst precursor in the same reactor in which the reduction was carried out.

The hydrogenation is generally carried out at a pressure of from 1 to 300 bar, in particular from 5 to 200 bar, preferably from 8 to 85 bar and particularly preferably from 10 to 65 bar. Preferably, the hydrogenation is carried out at a pressure of less than 65 bar as a low pressure method.

The temperature is usually in a range 40 to 250 ° C, in particular from 60 to 160 ° C, preferably from 70 to 150 ° C, particularly preferably from 80 to 130 ° C.

The hydrogenation may be e.g. in the liquid phase in a stirred autoclave, a bubble column, a circulation reactor such as a jet loop or a fixed bed reactor.

The catalyst can be separated from the product by methods known to those skilled in the art, for example filtration or settling.

Likewise, the hydrogenation in the gas phase can be carried out in a fixed bed reactor or a fluidized bed reactor. Common reactors for carrying out hydrogenation reactions are described, for example, in Ullmann's Encyclopaedia [Ullmann's Encyclopedia Electronic Release 2000, Chapter: Hydrogenation and Dehydrogenation, S2-3].

The hydrogenation is preferably carried out in suspension. In a particular embodiment, usually for reasons of simplifying the process, the hydrogenation is carried out in the same reaction vessel in which the catalyst precursor is also reduced.

The hydrogenation processes can be carried out batchwise, semi-continuously or continuously. The hydrogenation processes are preferably carried out semi-continuously or continuously.

The activity and / or selectivity of the catalysts according to the invention can decrease with increasing service life. Accordingly, a process for the regeneration of the catalysts according to the invention was found, in which the catalyst is treated with a liquid. The treatment of the catalyst with a liquid should lead to the removal of any adhering compounds which block active sites of the catalyst. The treatment of the catalyst with a liquid can be carried out by stirring the catalyst in a liquid or by washing the catalyst in the liquid, after treatment, the liquid can be separated by filtration or decanting together with the detached impurities from the catalyst.

Suitable liquids are generally the product of the hydrogenation, water or an organic solvent, preferably ethers, alcohols or amides.

In a further embodiment, the treatment of the catalyst with liquid can take place in the presence of hydrogen or of a gas containing hydrogen.

This regeneration can be carried out at elevated temperature, usually from 20 to 250 ° C. It is also possible to dry the used catalyst and to oxidize air-adhering organic compounds to volatile compounds such as CO2. Before further use of the catalyst in the hydrogenation of this must be activated after oxidation, as a rule, as described above.

In the regeneration, the catalyst can be post-doped with a compound of elements b). The post-doping can be carried out in such a way that the catalyst is impregnated or wetted with a water-soluble base of the element b).

An advantage of the invention is that the use of the catalyst according to the invention reduces the apparatus and investment requirements as well as the operating costs for plants in hydrogenation processes. In particular, the investment costs increase with increasing operating pressure and the use of solvents and additives. Since the hydrogenation process according to the invention is also carried out in the absence of water and ammonia ak can be operated, eliminating or simplify process steps for the separation of water and ammonia from the reaction product (distillation). The absence of water and ammonia makes it possible to make better use of the existing reactor volume, since the volume released can be used as an additional reaction volume.

By allowing the reduction of the catalyst precursor of the present invention to be carried out in a liquid, catalyst particles of small size and high surface area can be obtained.

The invention will be illustrated in the following examples.

definitions:

Catalyst loading is reported as the quotient of product amount and the product of catalyst mass and time.

Catalyst load = amount of product / (catalyst ^{mass •} reaction time)

The unit of catalyst loading is given in [kgp domestic product _ro / (kgκat h)] or [gp _ro domestic product / (gκat h)] Toggle.

The specified selectivities were determined by gas chromatographic analyzes and calculated from the area percentages. The educt conversion U (E) is calculated according to the following formula:

F% (E) _Ä - F% (E) _End

U (E) = -

F% (E) beginning

The yield of product A (P) results from the area percent of the product signal.

A (P) = F% (P),

wherein the area percent F% (i) of a starting material (F% (E)), product (F% (P)), a by-product (F% (N)) or quite generally a substance i (F% (i)), is the quotient of the area F (i) below the signal of the substance i and the total area Fcesamt, ie the sum of the area below the signals i, multiplied by 100, yields:

F% (i) = J ^ L • 100 = * ® ■ 100

^F Ge _Sϊm <L ^F W The selectivity of the starting material S (E) is calculated as the quotient of product yield A (P) and reactant conversion U (E):

A (P)

S (E) = U (E)

When DMAPN has been treated with dimethylamine (DMA), the area percentages refer to the total area without the area below the DMA signal.

F _Gesimt = ΣF (i) with i ≠ DMA

This is due to the assumption that the DMA found in the product is not due to cleavage of the starting material, but solely due to the previous addition.

Used abbreviations:

g: grams

Weight%: weight percent h: hour (s) kg: kilogram min .: minute ml: milliliter ppm: parts per million = parts per million parts

Vol.%: Volume percent

XRD: X-Ray Diffraction

ADN: adiponitrile

ACN: aminocapronitrile

DMA: dimethylamine

DMAPA: N, N-dimethylaminopropylamine

DMAPN: dimethylaminopropionitrile

HMD: hexamethylenediamine

THF: tetrahydrofuran

example 1

A) Preparation of a catalyst according to the invention:

In a high-pressure autoclave, 80 g of THF and 3.0 g of LiCoθ2 were combined. The autoclave was closed, the mixture made inert, and pressed to 10 bar hydrogen. It was heated to 150 ° C. under autogenous pressure and with stirring. Upon reaching This temperature was pressed to 10O bar of hydrogen. It was then reduced for 12 h. Thereafter, the autoclave was allowed to cool and relaxed to about 36 bar.

B) Hydrogenation of DMAPN:

Directly to the catalyst preparation (1A) then at a temperature of 100 ° C and a pressure of 36 bar 0.44 ml / min, crude DMAPN containing 2.5 wt.% DMA, pumped into the reactor while the pressure kept approximately constant by repressing hydrogen. This corresponds to a catalyst loading of 7.5 g DMAPN / (g LiCoO ₂ -Ii). In the period of 8 to 20 h, the selectivity of the obtained DMAPA in the crude feed was between 98.7 and 99.6%. After 20h the load was doubled. This resulted in a decrease in sales to 95% and a decrease in selectivity to 96.1%. By raising the temperature to 140 ° C and the pressure of 60 bar, the conversion could be increased again to full conversion, with the selectivity increased to 98.8% (53 h). Analysis of the effluent (62-74 h) for Li and Co was negative, with <1 ppm Li and Co detected.

Example 2

A) Preparation of a catalyst according to the invention:

In a stirred autoclave, 1, 5 g of LiCoO _{2 were combined} with 35 g of THF and activated at 150 ° C and 100 bar of hydrogen for 24 hours with vigorous stirring. After this time, the autoclave was allowed to cool and relaxed to 10 bar.

B) Hydrogenation of DMAPN:

Directly to the catalyst preparation (2A) then a temperature of 100 ° C was set. After reaching this temperature, a pressure of 36 bar was pressed with hydrogen. Subsequently, 24 g of pure DMAPN (catalyst loading = 7 g DMAPN / (g LiCoO ₂ -Ii)) were metered in with stirring over 2 h, while maintaining the pressure by repressuring of hydrogen approximately constant. After 2 h, the dosage was switched off, maintained for one minute and then removed 17 g of the reactor contents. This procedure was repeated 2 more times, with the second time taking 22 g and the third time 27 g of the reactor contents. The analyzes showed full conversion and a selectivity of 99.7% DMAPA. An analysis of the last discharge on Li and Co gave <1 ppm Co and about 1 ppm Li.

Examples 1 and 2 demonstrate the high performance of the catalysts according to the invention, which were prepared from the catalyst precursor LiCoO ₂ , over a long period of time. longer period. Furthermore, it could be shown that the Li contained in the precursor stage is not converted by the reduction in a soluble form and discharged in a continuous process. Another advantage evident from the examples is the fact that the catalyst can be activated in standard equipment under mild conditions. The water present at the beginning of the experiment is not required for the activity of the catalysts according to the invention, because it is removed continuously and yet the catalyst remains active.

Example 3

A) Preparation of a catalyst according to the invention:

In a high-pressure autoclave, 100 g of THF and 12 g of UCOO 2 were combined. The autoclave was closed, the mixture made inert, and pressed to 10 bar hydrogen. It was heated to 200 ° C. under autogenous pressure and with stirring. Upon reaching this temperature was pressed to 100 bar hydrogen. It was then reduced for 24 h. Thereafter, the autoclave was allowed to cool and it was depressurized under nitrogen. Subsequently, the catalyst (3A) was filtered off in a device under nitrogen pressure and washed with THF. The black paste (33.8 g) thus obtained had a dry matter content of about 37%.

B) Hydrogenation of unsaturated substrates:

The catalyst (3A) was then used to carry out the tests 3.1 to 3.5 listed in Table 1.

Catalyst load in [kg substrate / [kgkaf h] After the preparation of the catalyst (3A), the amount of catalyst indicated in the table was then added in a stirred autoclave and the amount of the template indicated in the table. Thereafter, the reactor was adjusted to the temperature indicated in the table. After reaching this temperature, the pressure stated in the table was pressed with hydrogen. Hydrogenation was then carried out in the "batch experiments" (3.1 to 3.3) after the stirrer had been switched on, while the pressure was kept constant by repressurizing hydrogen.The duration of the hydrogenation is indicated in the column "metering time / hydrogenation time" in table 2. Table 2 lists the conversions and selectivities of the products obtained.

Table 2: Hydrogenation results

^In addition to the product, mainly 36% cyclooctaene was found

In the "fed-batch experiments" (3.4 to 3.6), the amount of said educt indicated in the "metered amount" column was metered in with stirring while the catalyst precursor was being activated while the pressure was kept constant by repressing hydrogen , The analysis results after the indicated time are also given in Table 2.

Example 3 shows that very different selectivities containing unsaturated carbon-carbon, carbon-nitrogen or carbon-oxygen bonds can be hydrogenated with very good selectivities. Example 4

A) Preparation of a catalyst according to the invention:

1) doping of LJCOO2 with nickel

12 g of LiCoO 2 and 1.2 g of Ni (II) acetate tetrahydrate were vigorously stirred in 50 ml of deionized water in a sealed glass bottle for 10 hours. Thereafter, the black powder (4A-1) was filtered off, washed with water and THF.

2) Preparation of the catalyst:

13.2 g of the catalyst precursor thus treated (from Example 4A-1) were subsequently reduced in 100 g of THF at 200 ° C. and 100 bar for 24 h in a 300 ml hydrogenation autoclave. After reduction, 17.8 g of reduced, THF-wet catalyst was obtained by filtration. The catalyst (4A-2) thus obtained had a dry weight content of about 57%.

B) Hydrogenation of DMAPN:

2.2 g of the catalyst (4A-2) were then filled in a stirred autoclave and set a temperature of 100 ° C. After reaching this temperature, a pressure of 36 bar was sprayed with hydrogen. 48 g of pure DMAPN (catalyst charge = 4.1 g of DMAPN / (g _Ka t-h)) were then metered in with stirring over 8 h, while the pressure was kept approximately constant by repressing hydrogen. The sample after 8 hours of metering and hydrogenation gave 99.0% conversion, 99.7% selectivity to DMAPA.

Example 4 shows that the catalyst doped with Ni has a lower activity, but a higher selectivity in the hydrogenation of DMAPN than the undoped catalyst from Example 1A).

Example 5:

A) Use of a catalyst according to the invention for the hydrogenation of ADN:

6 g of LJCOO 2 were reduced in 80 g of THF as described in Example 2A. Subsequently, 60 g of ADN were metered in at 36 bar and 100 ^° C. for 6 hours. The hydrogen pressure was kept constant by continuous repressing of hydrogen. After 6 h, the ADN dosage was switched off and after-hydrogenated for a further 6 h. The gas chromato Tographic analysis of the sample after 6 h showed 99.8% conversion and 97.6% selectivity to HMD and ACN. Thereby, 97.0% HMD and 0.5% ACN had been formed.

Comparative Example 1

A) Preparation of a comparative catalyst:

In a high-pressure autoclave 6 g CO3O4 were combined with 80 g THF and activated at 200 ° C and 100 bar H2 for 12 hours with vigorous stirring. After this time, the autoclave was allowed to cool to 100 ° C and relaxed to 36 bar.

B) Hydrogenation of ADN:

Directly after the preparation of the comparative catalyst (V1-A) was at 100 ° C and 36 bar with stirring over 6 h 60 g of pure ADN (catalyst loading: 1, 7g ADN / (gκat -h)) dosed, and the pressure After pressing hydrogen at 36 bar maintained. After 6 h, the dosage was switched off and stirred for 6 h under the same conditions. Gas chromatographic analysis of the sample after 6 h showed 57% conversion and 87.7% selectivity to HMD and ACN. In this case, 30.5% HMD and 19.4% ACN had been formed. Gas chromatographic analysis of the sample after 12 h showed 81.0% conversion and 88.5% selectivity to HMD and ACN. Here, 44.4% HMD and 27.2% ACN had been formed.

Example 5 and Comparative Example 1 show that the catalyst prepared by reducing a catalyst precursor containing the mixed oxide structure of the present invention has advantages over a catalyst prepared by reducing a catalyst precursor consisting of pure cobalt oxide. With the same catalyst loading, the productivity of the catalyst of the present invention was far higher than that of the catalyst made from the pure co-oxide catalyst precursor. Even after 6 h post-hydrogenation time, this catalyst did not yet reach the conversion which had already been achieved after 6 h in the case of LiCoO 2, even though the reduction temperature had been higher by 50 ° C.

Example 6

A) Preparation of a catalyst precursor

Powdered magnesium carbonate and cobalt (II) carbonate hydrate (CAS 513-79-1) were intensively mixed in a ratio of 0.5: 1 [mol of Mg: mol of Co] and calcined in air in an oven. This was heated to 400 ° C in 2 h and held this temperature for 2 h. The oxide catalyst precursor thus obtained shows diffraction signals of CoO / MgO mixed crystals and a spinel structure in the XRD (X-ray diffraction). B) Preparation of a catalyst according to the invention:

The powder obtained from the cocination (Example 6A) was gassed with a gas stream of 90% by volume of N 2 and 10% by volume of H 2 in a heated nitrogen-inert reduction oven and heated to 300 ° C. over the course of 2 hours, 16 hours reduced at this temperature and then cooled. After cooling, the hydrogen-containing atmosphere was replaced with nitrogen. According to X-ray diffraction (XRD), the resulting reduced catalyst contains predominantly cubic and hexagonal cobalt and CoO / MgO.

The reduced catalyst (6B) thus obtained was used as described below under 6C).

C) Hydrogenation of DMAPN:

In a stirred autoclave, 3 g of the catalyst (6B) were combined with 35 g of DMAPA. It was pressed 10 bar of hydrogen and heated to 100 ° C with gentle stirring. After reaching this temperature, it was re-pressed to 36 bar H2 and started with the dosage of 6 g / h DMAPN. The hydrogen pressure was kept approximately constant by continuous repressing. After 8 h, the dosage was stopped and after-hydrogenated for another 3 h. A sample after 8 hours showed 99.8% conversion and 99.3% selectivity. After 11 h, the conversion was 99.95% and the selectivity 99.2%.

Example 7

A) Preparation of a catalyst precursor

Powdered lithium carbonate (CAS 554-13-2) and cobalt (II) carbonate hydrate (CAS 513-79-1) was mixed in a ratio of 1: 1 [mol Li: mol Co] and mixed in one

Kiln calcined in air. This was heated to 400 ° C in 2 h and held this temperature for 2 h. The catalyst precursor thus obtained had a Li: Co ratio of 1: 1 [mokmol] (from elemental analysis) and a surface area of 34 m ² / g (BET measurement). From the diffraction lines in the X-ray powder diffractogram (XRD, Cu-K-alpha radiation), it was concluded that the main crystalline component of this catalyst precursor is a LiCoO 2 mixed oxide.

B) Preparation of a catalyst according to the invention:

In a heated, nitrogen-inertized reduction furnace, the powder obtained from the CaI- cination (Example 7A) was gassed with a gas stream of 90 vol.% N2 and 10 vol.% H2 and heated to 300 ° C within 2 h, 16 h at this temperature reduced and then cooled. After cooling, the hydrogen-containing atmosphere was replaced with nitrogen.

The reduced catalyst (7B) thus obtained was used as described under 7C). To passivate the catalyst, air was slowly added to the nitrogen atmosphere until the nitrogen was completely replaced with air. The passivated catalyst thus obtained was used as described under 7D) and 7E).

C) Semi-batch hydrogenation of DMAPN:

With 3.0 g of the catalyst from Example 7B), a semi-batch experiment for DMAPN hydrogenation was carried out. In a stirred autoclave, 35 g of DMAPA were introduced and a temperature of 100 ° C was set. After reaching this temperature, a pressure of 36 bar was pressed with hydrogen. Then 35 g of DMAPN (catalyst loading about 2 g DMAPN / (g _Ka fh)) was metered in with stirring over 8 h while the pressure was kept approximately constant while repressing hydrogen. The sample after 8 hours of metering and hydrogenation gave 99.9% conversion and 99.6% selectivity to DMAPA.

D) Semi-batch hydrogenation of DMAPN:

With 3.0 g of the passivated catalyst from Example 7B), a semi-batch experiment for DMAPN hydrogenation was carried out. In a stirred autoclave 35 g of DMAPA were presented and set a temperature of 100 ⁰ C. After reaching this temperature, a pressure of 36 bar was pressed with hydrogen. Then 35 g of DMAPN (catalyst loading about 2 g DMAPN / (g _Ka fh)) was metered in with stirring over 8 h while the pressure was kept approximately constant while repressing hydrogen. The sample after 8 hours of metering and hydrogenation gave 99.9% conversion and 99.7% selectivity to DMAPA.

E) Continuous hydrogenation of DMAPN:

The passivated catalyst from Example 7B) was used in the continuous hydrogenation of DMAPN in suspension without preactivation. At a hydrogen pressure of 40 bar and 120 ° C, 2.5 wt.% Catalyst and a load of 1, 2 kg DMAPN / (kgκafh) was the experiment after 400 h at a constant high DMAPN conversion> 99.9% with consistent high selectivity of 99.5% terminated without signs of deactivation. Example 7 shows that the catalyst can be used completely reduced or passivated, whereby a separate activation of the passivated catalyst before the start of the hydrogenation is not absolutely necessary.

Example 7 also shows that the catalyst is also suitable for use in continuous processes.

Example 8

A) Preparation of a catalyst precursor

Powdered lithium carbonate (CAS 554-13-2) and cobalt (II) carbonate hydrate (CAS 513-79-1) was intensively mixed in a ratio of 0.8: 1 [mol Li: mol Co] and calcined in air in an oven , This was heated to 400 ° C in 2 h and held this temperature for 2 h. From the diffraction lines of the thus obtained catalyst precursor (8A) in the X-ray powder diffractogram (XRD, Cu-K-alpha radiation), it was concluded that in addition to the main crystalline component, a non-stoichiometric Li _x CO (i + χ / 3) θ 2 mixed oxide , there is still some CO3O4 present

B) Preparation of a catalyst according to the invention:

In a heated, nitrogen-inertized reduction furnace, the catalyst precursor (8A) obtained from the caπination was gassed with a gas stream of 90% by volume N 2 and 10% by volume of H 2 and heated to 300 ° C. within 2 hours, 16 h this temperature is reduced and then cooled. After cooling, the hydrogen atmosphere was replaced with nitrogen.

The resulting reduced catalyst (8B) was used as described under C).

C) Hydrogenation of DMAPN:

With 3.0 g of the catalyst (8B), a semi-batch experiment for DMAPN hydrogenation was carried out. In a stirred autoclave, 35 g of DMAPA were introduced and a temperature of 100 ° C was set. After reaching this temperature, a pressure of 36 bar was pressed with hydrogen. Then 35 g of DMAPN (catalyst loading about 2 g DMAPN / (g _Ka fh)) was metered in with stirring over 8 h while the pressure was kept approximately constant while repressing hydrogen. The sample after 8 hours of metering and hydrogenation gave 99.8% conversion and 99.8% selectivity to DMAPA.

Example 8 clarifies that catalyst precursors, which for the most part but not exclusively consist of a mixed oxide, are suitable according to the invention.

Claims

claims:

1. Catalysts obtainable by reacting a catalyst precursor containing a) cobalt and b) one or more elements of the alkali metal group, the alkaline earth metal group, the rare earth group or zinc or mixtures thereof, wherein the elements a) and b) at least partially in Form their mixed oxides present, reduced.

2. Catalyst according to claim 1, obtainable by using LJCOO2 as catalyst precursor.

3. A catalyst according to any one of claims 1 to 2, obtainable by using as a catalyst precursor LiCoθ2, which is obtained by the reprocessing of batteries used.

4. Catalyst according to at least one of claims 1 to 3, obtainable by carrying out the reduction of the catalyst precursor in a liquid.

5. A process for the preparation of catalysts, characterized in that comprising a catalyst precursor containing a) cobalt and b) one or more elements of the alkali metal group, the alkaline earth metal group, the rare earth or zinc group or mixtures thereof, wherein the elements a) and b ) are present, at least in part, in the form of their mixed oxides.

6. A process for the preparation of a catalyst according to claim 5, characterized in that is used as the catalyst precursor LiCoθ2.

7. A process for the hydrogenation of compounds containing at least one unsaturated carbon-carbon, carbon-nitrogen or carbon-oxygen bond, or the partial or complete nuclear hydrogenation of aromatics-containing compounds, characterized in that a catalyst obtainable according to at least one of claims 1 to 6, uses.

8. The method according to claim 7, for the preparation of primary amines from compounds containing at least one nitrile group.

9. The method according to at least one of claims 7 to 8, characterized in that one carries out the hydrogenation as a low pressure process.

10. A process for the regeneration of a catalyst obtainable according to any one of claims 1 to 6, characterized in that the catalyst is treated with a liquid.

11. Use of catalysts obtainable according to any one of claims 1 to 6 for the hydrogenation of compounds containing at least one unsaturated carbon-carbon, carbon-nitrogen or carbon-oxygen bonds, or the partial or complete nuclear hydrogenation of aromatics containing compounds.

12. Use of catalysts according to claim 1 1 for the preparation of primary amines from compounds containing at least one nitrile group.