Process for the manufacture of chemical products and passivation of heterogeneous metal catalysts

Abstract

Process for preparing a chemical product by reacting at least one substrate in a reactor or a series of reactors in the presence of hydrogen, a heterogenous metal catalyst and optionally ammonia to form at least one chemical product, the at least one substrate being introduced into the reactor or the series of reactors with a mass flow ms and hydrogen being introduced into the reactor or the series of reactors with a mass flow mH, and optional ammonia is introduced at a flow rate mNH3, wherein the event of (I) a replacement of the catalyst in the reactor or the series of reactors or (II) another event where the catalyst needs to be exposed to air, the mass flow ms and mH2 is reduced to zero and ammonia is introduced or continued to be introduced into the reactor or series of reactors at a mass flow m'NH3 and brought into contact with the catalyst and a process for the passivating a heterogenous metal catalyst, suitable for converting one or more substrates with the heterogenous metal catalyst in the presence hydrogen and optionally in the presence of ammonia to form at least one chemical product, comprising the steps of: a) stopping any flow of substrate and / or hydrogen over the catalyst; b) contacting the catalyst with ammonia at a mass flow m'NH3. The present invention also relates to the use of ammonia for passivating a heterogeneous metal catalyst prior to an event which requires contacting the heterogenous metal catalyst with air.

Description

[0001] Process for the Manufacture of Chemical Products and Passivation of Heterogeneous Metal Catalysts

[0002] Description

[0003] The present invention relates to a process for preparing a chemical product in the presence of hydrogen and a heterogeneous metal catalysts involving the passivation of a heterogenous metal catalyst.

[0004] The present invention further relates to a process for passivating a heterogenous metal catalysts. Heterogeneous metal catalysts are a class of catalysts that usually consist of solid metal or metalcontaining particles dispersed on a support material. These catalysts participate in chemical reactions at the interface between the solid catalyst surface and the liquid or gas phase reactants. Heterogeneous metal catalysts have widespread applications in various industries, including petrochemicals, fine chemicals, pharmaceuticals, automotive, and environmental sectors.

[0005] Typical types of reactions which are carried out in the presence of heterogenous metal catalysts and hydrogen are hydrogenation reactions, dehydrogenation reactions, redox reactions, hydrocracking, hydrodesulfurization, hydrodeoxygenation, hydrodehalogenation, hydrogenolysis synthesis, steam reforming, amination and transamination reactions.

[0006] Important products which are produced in the presence of heterogenous metal catalysts and hydrogen are ammonia, methanol, ethyleneamines, ethanolamines, cyclohexane, hydrogenated vegetable oils, fats or hydrocarbons and hydrogenated polymers.

[0007] In the presence of hydrogen, at least some of the metal comprised in the heterogeneous metal catalysts is in the oxidation state 0, that is at least some of the metal in the heterogenous metal catalyst is in its elemental form.

[0008] Since many active metals in their elemental form are very reactive with air or moisture, they can pose a significant safety risk during replacement handling, storage, and transportation of the catalysts, especially when the catalysts have a high surface area or are finely dispersed.

[0009] To reduce the safety risks during handling, storage and transportation, metals catalysts are usually passivated by forming a protective outer layer or film on their surfaces. This passivation layer usually prevents the metal catalyst from reacting with air, moisture, or other substances in its surroundings. The passivation layer is typically induced by exposing the catalyst to oxygen.

[0010] Since the oxidation of many metals is a highly exothermic reactions, temperature spikes may occur within the reactor. If the temperature is too high, the metal may begin to glow or even melt which may lead to a sintering of the catalyst and a reduction of active surface area. Another problem is that the gaseous stream, comprising oxygen s heated and that this hot gas stream further heats the catalysts in the downflow sections and further increases the problem of sintering in the downflow direction of the reactor. To prevent a loss of catalyst activity, passivation is often affected by exposing the catalyst to a gaseous stream comprising both oxygen and nitrogen. Passivation is usually commenced with a high ratio of nitrogen to oxygen in the gas stream and the oxygen concentration is usually only gradually increased to prevent a temperature build-up. This makes the process very time consuming. A long catalyst changeout time or replacement period increases the overall shutdown or turnaround time when the reactor is taken offline for catalyst replacement. The catalyst changeout period usually includes the time needed for passivating the active catalyst, removing the passivated catalyst, cleaning the reactor, loading the fresh catalyst, and restarting the reactor with the new catalyst. The duration of the catalyst changeout period depends on to a significant extend on the duration of the passivation step.

[0011] The object of the present invention was therefore to decrease the catalyst changeout time and to increase the time the reactor is available for production of chemical products. Decreasing the catalyst changeout time has the positive effect of increasing the time a chemical reactor is available for producing the desired products, thereby increasing average annual productivity. Another object of the present invention was to reduce safety risks while conducting a chemical process. Safety risks can be reduced, if the catalyst can be easily and quickly transformed into a state in which it can be handled safely. A further object of the present invention was to reduce the extent of exothermic heat produced during passivation, to prevent undesired heating which can lead to a loss of catalytic activity or selectivity, and to prevent unsafe situations during the passivation process.

[0012] In a first aspect, the invention therefore relates to: a process for preparing a chemical product by reacting a least one substrate in a reactor or a series of reactors in the presence of hydrogen, a heterogenous metal catalyst and optionally ammonia to form at least one chemical product, the at least one substrate being introduced into the reactor or the series of reactors with a mass flow ms and hydrogen being introduced into the reactor or the series of reactors with a mass flow mH, and optional ammonia is introduced at a flow rate mNH3, wherein the event of (i) a replacement of the catalyst in the reactor or the series of reactors or (ii) another event where the catalyst needs to be exposed to air, the mass flow mS and mH2 is reduced to zero and ammonia is introduced or continued to be introduced into the reactor or series of reactors at a mass flow m'NH3 and brought into contact with the catalyst.

[0013] In a second aspect, the present invention relates to: a process for the passivating a heterogenous metal catalyst, suitable for converting one or more substrates in the presence hydrogen and optionally in the presence of ammonia to form at least one chemical product, comprising the steps of: a) stopping any flow of substrate and / or hydrogen over the catalyst; b) contacting the catalyst with ammonia at a mass flow m

[0014] In a third aspect, the present invention relates to use of ammonia for passivating a heterogeneous metal catalyst prior to an event which requires contacting the heterogenous metal catalyst with air.

[0015] It was found that the passivation of the heterogenous metal catalyst with ammonia bears several advantages over the passivation with oxygen. The reaction with ammonia results in a stable nitride layer on the surface of the catalyst. Even though the nitridation of the catalyst surface should have a similar heat of reaction as an oxidation with an oxygen comprising gas, it was found that the temperature increase in reactors was significantly lower compared to the passivation with oxygen. Due to the lower temperature increase, critical conditions which lead to a deactivation or deterioration of the catalyst properties can be avoided. In addition, the catalyst changeout time could be reduced. It should be noted that the reduction of changeout times in the magnitude of hours can lead to significant savings, especially for very large-scale chemical plants which produce several hundred tons of product per day. A further advantage of the process of the present invention is that the ammonia passivated catalysts can be transformed into a conventional passivated catalyst with an oxide layer as the nitride layer is easily transformed in an oxide layer with little heat formation. Using the process of the present invention therefore enables obtaining a passivated catalyst with a protective oxide layer in a short time and with comparably little heat formation.

[0016] The fist aspect of the present invention comprises the step of preparing a chemical product in the presence of hydrogen and a heterogeneous metal catalyst.

[0017] The chemical product of the present invention is any type of product which can be produced by converting one or more substrates in the presence of hydrogen and a heterogenous metal catalyst.

[0018] Preferred types of reactions in which a substrate is converted to a product in the presence of hydrogen and a heterogenous metal catalysts are hydrogenation reactions, dehydrogenation reactions, hydrocracking, hydrodesulfurization, hydrodeoxygenation, hydro dehalogenation and hydrogenolysis reaction.

[0019] Preferred hydrogenation reactions comprise:

[0020] - the hydrogenation of unsaturated hydrocarbons, such as alkenes or alkynes,

[0021] - the hydrogenation of unsaturated fatty acids or vegetable oils,

[0022] - the hydrogenation or aromatic compounds to aliphatic compounds,

[0023] - the hydrogenation of carbonyl compounds, such as aldehydes or ketones to alcohols,

[0024] - the hydrogenation of carboxylic acids or ester to alcohols,

[0025] - the hydrogenation of nitriles to amines or imines, and

[0026] - the hydrogenation of nitro compounds to amines,

[0027] More preferred products which are produced by converting a substrate in the presence of hydrogen and a heterogenous metal catalyst are: ammonia (Haber-Bosch process) by conversion of nitrogen with hydrogen, methanol by conversion of carbon dioxide with hydrogen, hydrocarbons by conversion of carbon monoxide and hydrogen in a Fischer-Tropsch synthesis, hydrogenated vegetable oils or hydrocarbons by hydrogenation of unsaturated oils and fatty acids or unsaturated hydrocarbons, aniline by hydrogenation of nitrobenzene, cyclohexane by hydrogenation of benzene, ethylene oxide by conversion of carbon monoxide with hydrogen and subsequent hydrolysis to ethylene glycol, hydrogenated nitrile butadiene rubber from hydrogenation of nitril butadiene rubber, hydrogen peroxide produced from hydrogenation of anthraquinone, ethanol produced by hydrogenation of acetic acid or ethylene, styrene produced by dehydrogenation of ethylbenzene, toluene produced by hydrogenation of benzene followed by selective dehydrogenation, butanol produced by hydrogenation of butyraldehyde, hydrogenated polyisobutene produced from hydrogenation of polyisobutene, polyethylene produced by hydrogenation of propylene, hydrogenated bis-phenol A produced from the hydrogenation of bisphenol A, and hydrogenated naphthalene produced by the hydrogenation of naphthalene.

[0028] The above list of potential chemical products which can be produced in the process of the present invention is not exclusive and merely illustrative of the large number of products which can be produced from substrates with the process of the present invention.

[0029] In a preferred embodiment, the process of the present invention is conducted in the presence of ammonia or an aminating agent. Such processes have the advantage that the infrastructure for providing the ammonia required for the passivation of the heterogenous metal catalyst is usually already present at the production plant allowing to use synergies with already existing infrastructure. In case of the construction of new plants, the ammonia infrastructure does not need to be built in addition to the infrastructure required of producing the desired product.

[0030] In the case of an aminating agent which is not ammonia, the aminating agent is often derived from ammonia and therefore ammonia is also often present on the site of the plant. In addition, amination plants are often multi-product plants which allow the use of different aminating agents and ammonia is usually one aminating agent which is already integrated into the infrastructure of amination plants. The economy of the process of the present invention therefore further increases if the process of the present invention is carried out in the presence of ammonia or an aminating agent.

[0031] Reactions carried out in the presence of hydrogen, ammonia or an aminating agent and a heterogenous metal catalyst usually involve the synthesis of different nitrogen containing compounds.

[0032] Preferred products which can be produced within the preferred embodiment are:

[0033] - primary amines by hydrogenation of the corresponding nitriles,

[0034] - primary, secondary, and tertiary amines by reductive amination of the corresponding carbonyl compounds, preferably aldehydes and ketones,

[0035] - primary, secondary, and tertiary amines by amination of the corresponding alcohols,

[0036] - primary, secondary and tertiary amines by transamination of amines,

[0037] - amides by ammonolysis of corresponding esters.

[0038] Most preferred products are products which are prepared by converting substrates in the presence of a heterogeneous metal catalyst, hydrogen and ammonia. Such most preferred products are:

[0039] - primary amines by hydrogenation of the corresponding nitriles,

[0040] - primary, secondary, and tertiary amines by reductive amination of the corresponding carbonyl compounds, preferably aldehydes and ketones,

[0041] - primary, secondary, and tertiary amines by amination of the corresponding alcohols, - primary, secondary and tertiary amines by transamination of amines,

[0042] - amides by ammonolysis of corresponding esters, which are prepared in the presence of ammonia.

[0043] Hydrogenation of Nitriles: In a preferred embodiment, the substrate is a nitril which is hydrogenated to the corresponding primary amine, and which is preferably affected in the presence of ammonia to suppress formation of secondary and tertiary amines.

[0044] Nitriles which can be used as substrates in the present invention are any known:

[0045] (I) aromatic nitriles, such as C7-15 aromatic nitriles,

[0046] (II) cycloaliphatic nitriles, such as C1-100 cycloaliphatic nitriles, or

[0047] (III) aliphatic nitrile compounds, such as C1-100 aliphatic nitriles, or

[0048] (IV) other substituents comprising a total number of preferably 100, more preferably 60, hydrogen, carbon, nitrogen, phosphor, or sulfur atoms.

[0049] Examples of nitriles which can be used as substrates in the present invention are: acetonitrile, propionitrile, butyronitrile, valeronitrile, capronitrile, 2,2-dimethylpropanenitrile, 3- dimethylaminopropionitrile, enanthonitrile, caprylnitrile, pelargonitrile, caprinitrile, hendecanenitrile, lauronitrile, tridecanenitrile, myristonitrile, pentadecanenitrile, palmitonitrile, margaroninitrile, stearonitrile, phenylacetonitrile, malononitrile, succinonitrile, glutaronitrile, adiponitrile, 1 ,3,5-tricyanopentane, adiponitrodinitrile, methylglutaronitrile and succinodinitrile, isophorone nitrile, isophorone nitrile imine, cyclobutanecarbonitrile, cyclopentanecarbonitrile, cyclohexanecarbonitrile, 1 , 4-cyclohexanedicarbon itri le, 1 ,2,4,5-cyclohexanetetracarbonitrile, cycloheptanecarbonitrile, 3-methylcycloheptanecarbonitrile, cyclooctanecarbonitrile, aminoacetonitrile, iminobisacetonitrile and nitrilotriacetonitrile, methoxypropionitrile, biscyanoethyl ether, bis (2-cyanoethyl) ethylene glycol, bis (2-cyanoethyl) Mono (2- cyanoethyl) diethylene glycol) and bis (2-cyanoethyl) tetramethylene glycol, acrylonitrile, aminoproprionitrile, di (2-cyanoethyl) amine, N-methyl-p-aminopropionitrile, N, N-dimethyl-p- aminopropionitrile, N- (2-cyanoethyl) ethanolamine, N, N -Di (2-cyanoethyl) ethanolamine, N- (2- cyanoethyl) diethanolamine and N- (2-cyanoethyl) propanolamine, cyanoethylated acetamide, cyanoethylated propionamide, benzyl cyanide, benzonitrile, isophthalonitrile and terephthalalonitrile.

[0050] Reductive amination of aldehydes and ketones: In a further preferred embodiment, aldehydes and ketones are used as substrates and which are converted in the presence of hydrogen and an aminating agent to the corresponding amines. Such type of reaction is commonly referred to as reductive amination. In a preferred embodiment, the reduction amination of aldehydes and ketones is carried out in the presence of ammonia.

[0051] Aldehydes which can be used in the process of the invention are virtually all aliphatic and aromatic aldehydes. The aliphatic aldehydes can be linear, branched or cyclic, and the aldehydes can comprise heteroatoms. The aldehydes can also bear substituents or comprise functional groups which are inert under the conditions of the hydrogenative amination, for example alkoxy, alkenyloxy, alkylamino or dialkylamino groups, or may also be hydrogenated under the conditions of the hydrogenative amination, for example CC double (ethylenic) or triple (acetylenic) bonds. If polyfunctional aldehydes or keto aldehydes are to be aminated, amino alcohols, cyclic amines or multiply aminated products can be obtained by controlling the reaction conditions.

[0052] Preferred aldehydes can be described by the following formula: where R4is preferably alkyl, aryl, cycloalkyl, a heterocycle, or another substituent group having up to 100, preferably 60, carbon, sulfur, nitrogen or oxygen atoms in total in the substituent.

[0053] Examples of aldehydes include: formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, pivalalaldehyde, n-pentanal, n-hexanal, 2-ethylhexanal, 2-methylpentanal, 3- methylpentanal, 4-methylpentanal, glyoxal, benzaldehyde, p-methoxybenzaldehyde, p- methylbenzaldehyde, phenylacetaldehyde, (p-methoxyphenyl)acetaldehyde, (3,4- dimethoxyphenyl)acetaldehyde, 4-formyltetrahydropyran, 3-formyltetrahydrofuran, 5-formylvaleronitrile, citronellal, lysmeral, acrolein, methacrolein, ethylacrolein, citral, crotonaldehyde, 3- methoxypropionaldehyde, 3-aminopropionaldehyde, hydroxypivalalaldehyde, dimethylolpropionaldehyde, dimethylolbutyraldehyde, furfural, glyoxal, glutaraldehyde and also hydroformylated oligomers and polymers, e.g. hydroformylated polyisobutene (polyisobutene aldehyde) or the oligomer obtained by metathesis of 1 -pentene and cyclopentene and hydroformylated.

[0054] Ketones which can be used in the process of the invention are virtually all aliphatic and aromatic ketones. The aliphatic ketones can be linear, branched or cyclic, and the ketones can comprise heteroatoms. The ketones can also bear substituents or comprise functional groups which are inert under the conditions of the hydrogenative amination, for example alkoxy, alkenyloxy, alkylamino or dialkylamino groups, or may also be hydrogenated under the conditions of the hydrogenative amination, for example CC double (ethylenic) or triple (acetylenic) bonds. If polyfunctional ketones are to be aminated, amino ketones, amino alcohols, cyclic amines or multiply aminated products can be obtained by controlling the reaction conditions.

[0055] Preferred ketones can be described by the following formula: where R3and R4preferably can be jointly or independently hydrogen, alkyl, aryl, cycloalkyl, a heterocycle, or another substituent group having up to 100, preferably 60, carbon, sulfur, nitrogen or oxygen atoms in total in the substituent.

[0056] Examples of ketones include: acetone, ethyl methyl ketone, methyl vinyl ketone, isobutyl methyl ketone, butanone, 3-methylbutan-2-one, diethyl ketone, tetralone, acetophenone, p-methylacetophenone, p-methoxyacetophenone, m- methoxyacetophenone, 1 -acetylnaphthalene, 2-acetyl-naphthalene, 1-phenyl-3-butanone, cyclobutanone, cyclopentanone, cyclopentenone, cyclohexanone, cyclohexenone, 2,6-dimethylcyclohexanone, cycloheptanone, cyclododecanone, acetylacetone, methylglyoxal and benzophenone.

[0057] Alcohol amination:

[0058] In a further preferred embodiment, primary and secondary are used as substrates and which are converted in the presence of hydrogen and an aminating agent to the corresponding amines. Such type of reaction is commonly referred to as alcohol amination. In a preferred embodiment, alcohol amination is carried out in the presence of ammonia.

[0059] Suitable alcohols are, virtually all primary and secondary alcohols having an aliphatic OH function. The alcohols can be linear, branched or cyclic. Secondary alcohols are aminated just like primary alcohols. The alcohols can also bear substituents or comprise functional groups which are inert under the conditions of the hydrogenative amination, for example alkoxy, alkenyloxy, alkylamino or dialkylamino groups, or may be hydrogenated under the conditions of the hydrogenative amination, for example CC double (ethylenic) or triple (acetylenic) bonds. If polyhydric alcohols are to be aminated, it is possible to obtain amino alcohols, cyclic amines or multiply aminated products preferentially by controlling the reaction conditions. The amination of 1 ,4-diols usually leads to 1-amino-4-hydroxy compounds, 1 ,4-diamino compounds or five-membered rings containing a nitrogen atom (pyrrolidines).

[0060] The amination of 1 ,6-diols usually leads to 1-amino-6-hydroxy compounds, 1 ,6-diamino compounds or seven-membered rings containing a nitrogen atom (hexamethylenimines).

[0061] The amination of 1 ,5-diols usually leads to 1-amino-5-hydroxy compounds, 1 ,5-diamino compounds or sixmembered rings containing a nitrogen atom (piperidines, 1,5-dipiperidinylpentane). Accordingly, amination of diglycol (DEG) by means of NH3 can give monoaminodiglycol (=ADG=H2N— CH2CH2— 0— CH2CH2— OH), diaminodiglycol CH2N— CH2CH2— 0— CH2CH2— NH2) or particularly preferably morpholine. Correspondingly, piperazine is particularly preferably obtained from diethanolamine. N-(2- hydroxyethyl)piperazine can be obtained from triethanolamine.

[0062] Preferred alcohols can be described by following formula: where R3and R4preferably can be jointly or independently hydrogen, alkyl, aryl, cycloalkyl, a heterocycle, or another substituent group having up to 100, preferably 60, carbon, sulfur, nitrogen or oxygen atoms in total in the substituent.

[0063] Preference is given to aminating, for example, the following alcohols: methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, n-pentanol, n-hexanol, 2-ethylhexanol, tridecanol, stearyl alcohol, palmityl alcohol, cyclobutanol, cyclopentanol, cyclohexanol, benzyl alcohol, 2- phenylethanol, 2-(p-methoxyphenyl)-ethanol, 2-(3,4-dimethoxyphenyl)ethanol, 1-phenyl-3-butanol, ethanolamine, n-pro-panolamine, isopropanolamine, 2-amino-1-propanol, 1-methoxy-2-propanol, 3-amino- 2, 2-dimethyl-1 -propanol, n-pentanolamine (1-amino-5-pentanol), n-hexanolamine (1-amino-6-hexanol), ethanolamine, diethanolamine, triethanolamine, N-alkyldiethanol-amines, diisopropanolamine, 3-(2- hydroxyethylamino)propan-1-ol, 2-(N,N-dimethylamino)ethanol, 2-(N,N-diethylamino)ethanol, 2-(N,N-di-n- propylamino)ethanol, 2-(N,N-diisopropylamino)ethanol, 2-(N N-di-n-butylamino)ethanol, 2-(N,N-diisobutyl- amino)ethanol, 2-(N,N-di-sec-butylamino)ethanol, 2-(N,N-di-tert-butylamino)ethanol, 3-(N,N- dimethylamino)propanol, 3-(N,N-diethylamino)propanol, 3-(N,N-di-n-propyl-amino)propanol, 3-(N,N- diisopropylamino)propanol, 3-(N,N-di-n-butylamino)propanol, 3-(N,N-diisobutylamino)propanol, 3-(N,N-di- sec-butylamino)propanol, 3-(N,N-di-tert-butylamino)propanol, 1-dimethylamino-4-pentanol, 1-diethylamino- 4-pentanol, ethylene glycol, 1 ,2-propylene glycol, 1 ,3-propylene glycol, diglycol, 1,4-butanediol, 1,5-pen- tanediol, 1 ,6-hexanediol, 2,2-bis[4-hydroxycyclohexyl]propane, methoxyethanol, propoxyethanol, butoxyethanol, polypropyl alcohols, polyethylene glycol ethers, polypropylene glycol ethers and polybutylene glycol ethers. In the process of the invention, the polyalkylene glycol ethers mentioned last are converted into the corresponding amines by transformation of their free hydroxyl groups.

[0064] Particularly preferred alcohols are methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, 1,4- butanediol, 1 ,5-pentanediol, 1 ,6-hexanediol, 2-ethylhexanol, cyclohexanol, fatty alcohols, ethylene glycol, diethylene glycol (DEG), triethylene glycol (TEG), 2-(2-dimethylaminoethoxy)ethanol, N- methyldiethanolamine, ethanolamine and 2-(2-di-methylaminoethoxy)ethanol.

[0065] As set out above aldehydes or ketones, in the case of a reductive amination, and alcohols, in the case of alcohol aminations are conducted in the presence of an aminating agent.

[0066] Aminating agents are usually ammonia and primary and secondary amines. Preferred aminating agents are nitrogen compounds of the following formula: where R1and R2preferably can be jointly or independently hydrogen, alkyl, aryl, cycloalkyl, a heterocycle, or another substituent group having up to 100, preferably 60, carbon, sulfur, nitrogen or oxygen atoms in total in the substituent.

[0067] Primary or secondary amines can also be used like ammonia as aminating agents.

[0068] These aminating agents are preferably used for preparing unsymmetrically substituted dialkylamines or trialkylamines, e.g. ethyldiisopropylamine and ethyldicyclohexylamine. For example, the following monoalkylamines and dialkylamines are preferably used as aminating agents: monomethylamine, dimethylamine, monoethylamine, diethylamine, n-propyl-amine, di-n-propylamine, isopropylamine, diisopropylamine, isopropylethylamine, n-butylamine, di-n-butylamine, s-butylamine, di-s-butylamine, isobutylamine, n-pentylamine, s-pentylamine, isopentylamine, n-hexylamine, s-hexylamine, isohexylamine, cyclohexylamine, aniline, toluidine, piperidine, morpholine and pyrrolidine.

[0069] Ammonia is a particularly preferred aminating agent. When using ammonia as an aminating agent, the alcoholic hydroxyl group or the aldehyde group or the keto group is usually firstly converted into a primary amino group (— NH2). The primary amine formed in this way can react with further alcohol or aldehyde or ketone to form the corresponding secondary amine and this can in turn react with further alcohol or aldehyde or ketone to form the corresponding, preferably symmetrical, tertiary amine. Depending on the composition of the reaction mixture or the feed stream (in the case of continuous operation) and depending on the reaction conditions employed, viz. pressure, temperature, reaction time (space velocity over the catalyst), primary, secondary or tertiary amines can be prepared preferentially as desired in this way. Polyhydric alcohols or dialdehydes or oligoaldehydes or diketones or oligoketones or keto aldehydes can be converted with ammonia by intramolecular hydrogenative amination into cyclic amines such as pyrrolidines, piperidines, hexamethylenimines, piperazines and morpholines.

[0070] Amines which are particularly preferably prepared by reductive amination or alcohol amination are, for example, morpholine (from monoaminodiglycol), monoaminodiglycol, morpholine and / or bis(2- morpholinoethyl)ether (DMDEE) (from DEG and ammonia), 6-dimethyl-amino-1 -hexanol (from hexanediol and dimethylamine (DMA)), triethylamine (from ethanol and diethylamine (DEA)), dimethylethylamine (from ethanol and DMA), N— (01 -4-alkyl)morpholine (from DEG and mono(C1-4-alkyl)amine), N— (C1-4- alkyl)piperidine (from 1 ,5-pentanediol and mono(C1-4-alkyl)amine), piperazine and / or diethylenetriamine (DETA) (from N-(2-aminoethyl)ethanolamine (AEEA) and ammonia), N-methyl-piperazine (from diethanolamine and MMA), N, N'-dimethylpiperazine (from N-methyl-diethanolamine and MMA), 1 ,2- ethylenediamine (EDA) and / or diethylenetriamine (DETA) and / or PIP (from monoethanolamine(MEOA) and / or ethylene glycol (MEG) and ammonia), 2-ethylhexylamine and bis(2-ethylhexyl)amine (from 2- ethylhexanol and NH3), tridecylamine and bis(tridecyl)amine (from tridecanol and NH3), n-octylamine (from n-octanol and NH3), 1 ,2-propylenediamine (from 2-hydroxypropylamine and NH3), 1 -diethylamino-4- aminopentane (from 1-diethylamino-4-hydroxypentane and NH3), N, N-di(C1 -4-alkyl)cyclohexylamine (from cyclohexanone and / or cyclohexanol and di(C1-4-alkyl)amine), e.g. N,N-dimethyl-N-cyclohexylamine (DMCHA), polyisobutenamine (PIBA; with e.g. n~1000) (from polyisobutenaldehyde and NH3), N— N- diisopropyl-N-ethylamine (HUnig base) (from N— N-diisopropylamine and acetaldehyde, N-methyl-N- isopropylamine (MMIPA) (from monomethylamine and acetone), n-propylamines (such as mono- / di-n- propylamine, N,N-dimethyl-N-n-propylamine (DMPA) (from propionaldehyde and / or n-propanol and NH3 or DMA), N, N-dimethyl-N-isopropylamine (DMIPA) (from i-propanol and / or acetone and DMA), N,N- dimethyl-N-butylamines (1 -butanol, 2-butanol or isobutanol and / or butanal, i-butanal or butanone and DMA), 2-(2-di(C1-4-alkyl)aminoethoxy)ethanol and / or bis(2-di(C1 -4-alkyl)aminoethyl)ether (from DEG and di(C1-4-alkyl)amine), 1 ,2-ethylenediamine (EDA), monoethanolamine (MEOA), diethylenetriamine (DETA) and / or piperazine (PIP) (from monoethylene glycol (MEG) and ammonia), 1 ,8-diamino-3,6-dioxaoctane and / or 1-amino-8-hydroxy-3,6-dioxaoctane (from triethylene glycol (TEG) and ammonia), 1-methoxy-2- propylamine (1-methoxyisopropylamine, MOIPA) (from 1-methoxy-2-propanol and ammonia), N- cyclododecyl-2,6-dimethylmorpholine (dodemorph) (from cyclododecanone and / or cyclododecanol and 2,6-dimethylmorpholine), polyetheramine (from the corresponding polyether alcohol and ammonia). The polyether alcohols are, for example, polyethylene glycols or polypropylene glycols having a molecular weight in the range from 200 to 5000 g / mol, and the corresponding polyether amines are obtainable, for example, under the trade name PEA D230, D400, D2000, T403 or T5000 from BASF. In a particularly preferred embodiment, ethanolamine and or ethylene glycol are aminated with ammonia to form a mixture of ethyleneamines and ethanolamines, such as ethylene diamine (EDA), diethylene triamine (DETA), triethylenetetramine (TETA), tetraethylene pentaamine (TEPA), aminoethylethyleneamine (AEEA), piperazin (PIP), aminoethyl piperazine (AEP) and hydroxyethyl piperazine (HEP).

[0071] Amides by Ammonolysis of Esters:

[0072] A further preferred product that can be prepared according to the present invention are amides which are obtainable by reacting an ester RCOOR' with ammonia under suitable reaction conditions and where R and R' preferably can be jointly or independently alkyl, aryl, cycloalkyl, a heterocycle, or another substituent group having up to 100, preferably 60, carbon, sulfur, nitrogen or oxygen atoms in total in the substituent. Ammonolysis usually yields the corresponding amides RCOONH2 and alcohols R'OH.

[0073] Typical amides which can be prepared by the method of the present invention are; acetamide, benzamide, formamide, acrylamide, methacrylamide, N-methylacetamide, N,N- dimethylacetamide, N,N-diethylacetamide, N,N-dipropylacetamide, N,N-dibutylacetamide, N,N- dimethylformamide, N,N-diethylformamide, N,N-dipropylformamide, N-phenylacetamide, N- phenylformamide, N-(4-methylphenyl)acetamide, N-(4-methylphenyl)formamide, N-(4- methoxyphenyl)acetamide, N-(4-methoxyphenyl)formamide, N-(4-chlorophenyl)acetamide, N-(4- chlorophenyl)formamide, N-(4-bromophenyl)acetamide, N-(4-bromophenyl)formamide, N-(4- nitrophenyl)acetamide, N-(4-nitrophenyl)formamide, N-(4-aminophenyl)acetamide, N-(4- aminophenyl)formamide, N-(4-hydroxyphenyl)acetamide, N-(4-hydroxyphenyl)formamide, Naphthylacetamide, Naphthylformamide, N-(4-chloronaphthyl)acetamide, N-(4-chloronaphthyl)formamide, N-(4-bromonaphthyl)acetamide, N-(4-bromonaphthyl)formamide, N-(4-methoxynaphthyl)acetamide, N-(4- methoxynaphthyl)formamide, N-(4-aminonaphthyl)acetamide, N-(4-aminonaphthyl)formamide, N-(4- hydroxynaphthyl)acetamide, N-(4-hydroxynaphthyl)formamide, N-alkylated benzamides, N-alkylated naphthylamides, N-alkylated phenylacetamides, N-alkylated phenylformamides, N-arylalkylated acetamides, N-arylalkylated formamides, N-arylalkylated benzamides, N-arylalkylated naphthylamides, N- arylalkylated phenylacetamides, N-arylalkylated phenylformamides.

[0074] Amines by Transamination:

[0075] Transamination is usually understood to be the transfer of an amino group from one chemical compound to another, or the transposition of an amino group within a chemical compound.

[0076] Preferable chemical compounds that can be transaminated are alkyleneamines, such alkyleneamines preferably comprising at least two primary or secondary amine functionalities.

[0077] Several examples of suitable alkyleneamines include ethylenediamine, propylenediamine, diethylenetriamine, linear and branched triethylenetetramines, linear and branched tetraethylenepentamines, and analogous higher homologues of polyethylenepolyamine and polypropylenepolyamine up to about twelve amine moieties. When a lower molecular weight alkyleneamine, such as ethylenediamine or diethylenetriamine, is employed as the feedstock, usually it reacts with itself to build a product mixture containing higher molecular weight poly alkylenepolyamines.

[0078] In such instances, the preferred feedstock materials can be represented by the general formula:

[0079] RHN-[-( C)xHR— B]— (C)xHR— NHR wherein each B is independently NR or 0; each R is independently hydrogen, a C1 -C12 alkyl moiety such as methyl, ethyl, or propyl, a C1 -C12 amino alkyl moiety, phenyl or an alkyl-substituted phenyl, such as tolyl or xylyl, and wherein when R is attached to an alkylene group, R can also be an amino (NH2) moiety; each x is independently a number from 1 to about 12; and n is a number from 0 to 3. Preferably, each B is NR. More preferably, each B is NR, and each R is hydrogen. Even more preferably, each B is NR, each R is hydrogen, x is 2, and the lower molecular weight alkyleneamine is ethylenediamine, diethylenetriamine, triethylenetetramine, or a mixture thereof. Most preferably, the lower molecular weight alkyleneamine is ethylenediamine.

[0080] When a high molecular weight alkyleneamine, such as polyethylenepolyamine, is employed as the feedstock, usually it is cracked to form a product mixture containing lower molecular weight alkyleneamines. In such instances, the preferred linear starting materials can be represented by the above-identified general formula with the exception that n is at least 4, and preferably from about 5 to about 150. High molecular weight materials, however, almost always contain many branched isomers which are suitable for the process of this invention, but which are not amenable to a preferred structure.

[0081] Heterogenous Metal Catalyst

[0082] The process of the present invention is conducted in the presence of a heterogeneous metal catalyst. The catalysts may in principle comprise nickel, cobalt, iron, copper, chromium, manganese, copper, molybdenum, tungsten and / or other metals of groups 8 and / or 9 and / or 10 and / or 11 of the periodic table of the elements.

[0083] Preference is given to using catalysts which comprise at least one metal selected from the group consisting of Fe, Cu, Co, Ni, Sn, Pd, Pt, Ru, Rh, Ag, Au, Re, Os and Ir.

[0084] More preference is given to using catalysts which comprise at least one metal selected from the group consisting of Fe, Co, and Ni.

[0085] The abovementioned catalysts can be doped in a customary manner with promoters, for example with chromium, iron, cobalt, manganese, molybdenum, titanium, tin, metals of the alkali metal group, metals of the alkaline earth metal group and / or phosphorus.

[0086] The catalyst can be a supported or unsupported catalyst.

[0087] Suitable support materials are carbon compounds such as graphite, carbon black and / or activated carbon, aluminum oxide (gamma, delta, theta, alpha, kappa, chi or mixtures thereof), silicon dioxide, zirconium dioxide, zeolites, aluminosilicates or mixtures thereof. In a preferred embodiment of the invention, catalysts of the Raney type are being used. As Raney catalysts, Raney cobalt catalysts, Raney nickel catalysts and I or Raney copper catalysts are preferably used. Raney cobalt catalysts are particularly preferred.

[0088] In a further preferred embodiment of the invention the catalysts are prepared by reduction of a catalyst precursor, in which the aforementioned metals are present in the form of oxygen comprising compounds, such as their oxides, carbonates or hydrogencarbonates.

[0089] The catalyst precursors can be prepared by known processes, for example by precipitation, precipitative application, or impregnation.

[0090] In a preferred embodiment, catalyst precursors which are prepared by impregnating support materials are used in the process according to the invention (impregnated catalyst precursors).

[0091] The support materials used in the impregnation can, for example, be used in the form of powders or shaped bodies, such as extrudates, tablets, spheres or rings. Support material suitable for fluidized bed reactors is preferably obtained by spray drying.

[0092] Useful support materials include, for example, carbon such as graphite, carbon black and / or activated carbon, aluminum oxide (gamma, delta, theta, alpha, kappa, chi or mixtures thereof), silicon dioxide, zirconium dioxide, zeolites, aluminosilicates or mixtures thereof.

[0093] The abovementioned support materials can be impregnated by the customary methods, for example by applying a metal salt solution in one or more impregnation stages. Useful metal salts generally include water-soluble metal salts, such as the nitrates, acetates or chlorides of the corresponding catalytically active components or the doping elements, such as cobalt nitrate or cobalt chloride. Thereafter, the impregnated support material is generally dried and optionally calcined.

[0094] The impregnation can also be affected by the so-called "incipient wetness method", in which the support material is moistened with the impregnating solution up to a maximum of saturation according to its water absorption capacity. However, the impregnation can also be affected in supernatant solution.

[0095] In the case of multistage impregnation processes, it is appropriate to dry and if appropriate to calcine between individual impregnation steps. Multistage impregnation can be employed advantageously when the support material is to be contacted with metal salts in a relatively large amount.

[0096] To apply a plurality of metal components to the support material, the impregnation can be affected simultaneously with all metal salts or in any desired sequence of the individual metal salts.

[0097] In a further preferred embodiment, catalyst precursors are prepared by means of a coprecipitation of all their components. To this end, in general, a soluble compound of the corresponding active component and of the doping elements, and optionally a soluble compound of a support material is admixed with a precipitant in a liquid while heating and while stirring until the precipitation is complete.

[0098] The liquid used is generally water.

[0099] Useful soluble compounds of the active components typically include the corresponding metal salts, such as the nitrates, sulfates, acetates or chlorides of the aforementioned metals. The soluble compounds of a support material used are generally water-soluble compounds of Ti, Al, Zr, Si etc., for example the water-soluble nitrates, sulfates, acetates or chlorides of these elements.

[0100] The soluble compounds of the doping elements used are generally water-soluble compounds of the doping elements, for example the water-soluble nitrates, sulfates, acetates or chlorides of these elements.

[0101] Catalyst precursors can also be prepared by precipitative application.

[0102] Precipitative application is understood to mean a preparation method in which a sparingly soluble or insoluble support material is suspended in a liquid and then soluble compounds, such as soluble metal salts, of the appropriate metal oxides, are added, which are then precipitated onto the suspended support by adding a precipitant.

[0103] Useful sparingly soluble or insoluble support materials include, for example, carbon compounds such as graphite, carbon black and / or activated carbon, aluminum oxide (gamma, delta, theta, alpha, kappa, chi or mixtures thereof), silicon dioxide, zirconium dioxide, zeolites, aluminosilicates or mixtures thereof.

[0104] The support material is generally present in the form of powder or spall.

[0105] The liquid used, in which the support material is suspended, is typically water.

[0106] Useful soluble compounds include the aforementioned soluble compounds of the active components or of the doping elements.

[0107] Typically, in the precipitation reactions, the soluble compounds are precipitated as sparingly soluble or insoluble basic salts by adding a precipitant.

[0108] The precipitants used are preferably alkalis, especially mineral bases, such as alkali metal bases. Examples of precipitants are sodium carbonate, sodium hydroxide, potassium carbonate or potassium hydroxide.

[0109] The precipitants used may also be ammonium salts, for example ammonium halides, ammonium carbonate, ammonium hydroxide or ammonium carboxylates.

[0110] The precipitation reactions can be performed, for example, at temperatures of 20 to 100°C, preferably 30 to 90°C, especially at 50 to 70°C.

[0111] The precipitates formed in the precipitation reactions are generally chemically inhomogeneous and generally comprise mixtures of the oxides, oxide hydrates, hydroxides, carbonates and / or hydrogencarbonates of the metals used. It may be found to be favorable for the filterability of the precipitates when they are aged, i.e. when they are left alone for a certain time after the precipitation, if appropriate under hot conditions or while passing air through.

[0112] The precipitates obtained by these precipitation processes are typically processed by washing, drying, calcining and conditioning them.

[0113] After washing, the precipitates are generally dried at 80 to 200°C, preferably 100 to 150°C, and then calcined.

[0114] The calcination is performed generally at temperatures between 300 and 800°C, preferably 350 to 600°C, especially at 450 to 550°C. After the calcination, the pulverulent catalyst precursors obtained by precipitation reactions are typically conditioned.

[0115] The conditioning can be affected, for example, by adjusting the precipitation catalyst to a particular particle size by grinding.

[0116] After the grinding, the catalyst precursor obtained by precipitation reactions can be mixed with shaping assistants such as graphite or stearic acid and processed further to shaped bodies.

[0117] The process for shaping can provide shaped bodies in any three-dimensional shape, for example round, angular, elongated or the like, for example in the form of extrudates, tablets, granules, spheres, cylinders or grains. Common processes for shaping are, for example, extrusion, tableting, i.e. mechanical pressing, or pelletizing, i.e. compacting by circular and / or rotating motions.

[0118] The conditioning or shaping is generally followed by a heat treatment. The temperatures in the heat treatment typically correspond to the temperatures in the calcination.

[0119] After calcination, the catalyst precursors obtained by precipitation reactions, such as coprecipitation or precipitative application, or impregnation usually comprise the catalytically active components in the form of a mixture of oxygen compounds thereof, i.e. especially as the oxides, mixed oxides and / or hydroxides. The catalyst precursors thus prepared can be stored as such.

[0120] The catalyst which is used in the process according to the invention is usually obtained by reducing catalyst precursors which have been prepared by impregnation or precipitation as described above after the calcination or conditioning.

[0121] The reduction of the dry catalyst precursor can be performed at elevated temperature in a moving or stationary reduction oven.

[0122] The reducing agent used is typically hydrogen or a hydrogen-comprising gas.

[0123] The catalyst precursor is preferably reduced in a reactor in which the shaped catalyst bodies are arranged as a fixed bed. The catalyst precursor is more preferably reduced in the same reactor in which the conversion of glycolaldehyde with the aminating agent is carried out.

[0124] Alternatively, the catalyst precursor can be reduced in a separate fluidized bed reactor in the fluidized bed. The catalyst precursor is generally reduced at reduction temperatures of 50 to 600°C, especially of 100 to 500°C, more preferably of 150 to 450°C.

[0125] The partial hydrogen pressure is generally from 1 to 300 bar, especially from 1 to 200 bar, more preferably from 1 to 100 bar, where the pressure figures here and hereinafter are based on the absolute measured pressure.

[0126] The duration of the reduction is preferably 1 to 20 hours and more preferably 5 to 15 hours.

[0127] During the reduction, a solvent can be supplied in order to remove water of reaction which forms and / or in order, for example, to be able to heat the reactor more rapidly and / or to be able to better remove the heat during the reduction. In this case, the solvent can also be supplied in supercritical form. Suitable solvents used may be the above-described solvents. Preferred solvents are water; ethers such as methyl tert-butyl ether, ethyl tert-butyl ether, dioxane or tetrahydrofuran. Particular preference is given to water or tetrahydrofuran. Suitable solvents likewise include suitable mixtures.

[0128] The catalyst precursor can also be reduced in suspension, for example in a stirred autoclave. The temperatures are generally within a range from 50 to 300°C, especially from 100 to 250°C, more preferably from 120 to 200°C.

[0129] The reduction in suspension is generally performed at a partial hydrogen pressure of 1 to 300 bar, preferably from 10 to 250 bar, more preferably from 30 to 200 bar. Useful solvents include the aforementioned solvents.

[0130] The duration of the reduction in suspension is preferably 5 to 20 hours, more preferably 8 to 15 hours.

[0131] The catalyst can be handled under inert conditions after the reduction. The catalyst can preferably be handled and stored 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 used. If appropriate, the catalyst must then be freed of the inert liquid before commencement of the actual reaction. Handling of a reduced catalyst under inert conditions is however more complicated than handling a catalyst under atmospheric conditions. It therefore preferred that after the reduction, the catalyst is be contacted with an oxygencomprising gas stream such as air or a mixture of air with nitrogen. This affords a passivated catalyst. The passivated catalyst generally has a protective oxide layer. This protective oxide layer simplifies the handling and storage of the catalyst, such that, for example, the installation of the passivated catalyst into the reactor is simplified. Preferably, the heterogenous metal catalyst is built into the reactor in its passivated form.

[0132] After passivation, the catalyst is usually activated. A catalyst can be activated by reducing a passivated catalyst. A passivated catalyst can be reduced as described above by treating the passivated catalyst with hydrogen or a hydrogen-comprising gas. The reduction conditions correspond generally to the reduction conditions employed in the reduction of the catalyst precursors. The activation generally eliminates the protective passivation layer.

[0133] An activated catalyst should be preferably handled under inert conditions during and after the activating reduction thereof as described above.

[0134] Therefore, activation of the catalyst is preferably conducted in the reactor where the conversion of the substrate occurs. In still a further preferred embodiment, the activation of the heterogenous metal catalyst is conducted in situ while the catalyst is being contacted with hydrogen, substrate and optionally ammonia.

[0135] Reactors:

[0136] The conversion of the substrate in the presence of hydrogen, the heterogenous metal catalyst and optionally ammonia can proceed in a suitable chemical reactor.

[0137] Suitable chemical reactors are fixed-bed reactors, fluidized-bed reactors, slurry reactors, trickle-bed reactors, membrane reactors or microreactors. Preferably, the conversion of the substrate is carried out in one or more fixed bed reactors.

[0138] Fixed bed reactors are one of the most widely used reactor types for heterogeneous catalytic reactions. They usually consist of a cylindrical vessel filled with a bed of solid catalyst particles, where the substrate and hydrogen gas are passed through the bed of catalyst particles. The reaction usually occurs on the surface of the catalyst, and the product is usually collected at the reactor outlet. Fixed-bed reactors are suitable for gas-phase or liquid-phase reactions.

[0139] In a fixed bed reactor, the catalyst is usually arranged in a fixed bed. If the catalyst is arranged as a fixed bed, it is preferred to shape the catalyst into suitable shapes, such as tables, cylinders or other extrudates. The catalyst bed optionally contains inert particles which are, for instance, interspersed throughout the bed and / or form discrete layers, e.g., at an end or intermediary to the bed. Preferably, flow through a catalyst bed is substantially plug flow. The proportion of the packing elements in such catalyst preparations can be from 20 to 80 parts by volume, preferably from 30 to 60 parts by volume and particularly preferably from 40 to 50 parts by volume.

[0140] Especially preferred types of fixed bed reactors are adiabatic fixed bed reactors, isothermal fixed reactors, multi-tubular fixed bed reactors, radial flow fixed-bed reactors, multi-stage fixed bed reactors, monolith reactors or suitable combinations thereof.

[0141] The reactor can be one reactor or a series of reactors.

[0142] The choice of the reactor type depends on the specific reaction requirements, such as reaction kinetics, heat and mass transfer, and pressure drop considerations.

[0143] Especially preferred reactors used in the present invention are adiabatic reactors which usually do not have equipment for heat exchange with the surroundings and are often even insulated to reduce heat transfer with the surroundings. In such reactors, usually a substantial part of the heat is not dissipated to the surroundings so that the temperature of at least some parts of the reactors increases during exothermic reactions taking place inside the reactor. Catalysts in such reactors are particularly prone to the negative effects of heat generation during passivation as the generated heat is usually not dissipated, which potentially results in undesired temperature spikes in at least some parts of the reactor.

[0144] Especially preferred adiabatic reactors are adiabatic fixed bed reactors.

[0145] Flow Rates:

[0146] In order to carry out the reaction according to the present invention, the at least one substrate, hydrogen and optionally ammonia are introduced into the reactor or a series of reactors at a mass flow rate ms(mass flow rate of substrate), mH (mass flow rate of hydrogen) and ITINH3 (mass flow rate of ammonia), whereby each mass flow rate is expressed as the ratio of the mass of substrate per time unit and is usually given in the units of kg / hr. In case of more than one substrate, the mass flow rate of substrate refers to the sum of all mass flow rates of individual substrates but excluding the flow rates of hydrogen and ammonia. Typical values for the mass flow rate depend on the kind of reaction the at least one substrate is submitted to in the reactor or series of reactors, the size and geometry of the reactor, the reaction kinetics, the thermodynamics of the system and other factors. In accordance with the invention, the mass flow rates ms, mH and muna (if present) are not zero as to bring the substrate, hydrogen and ammonia into contact with the heterogenous metal catalyst to carry out the reaction.

[0147] Preferably, the mass flow rate of substrate ms is adjusted as to achieve a weight hourly space velocity (mass of substrate per mass of the catalyst per hour) in the range of 0.1 to 50000, preferably 0.2 to 30000 and more preferably 0.5 to 20000 h1.

[0148] The mass flow rate of hydrogen mH is typically selected to adjust the desired molar ratio of hydrogen to substrate, which is preferably in the range of 1 :1000 to 1000:1, more preferably 1 :500 to 500:1 and even more preferably 1 :100 to 100:1.

[0149] The mass flow rate of ammonia ITINHS, if present, is typically selected to adjust the desired molar ratio of ammonia to substrate, which is preferably in the range of 1 :1000 to 1000:1, more preferably 1 :500 to 500:1 and even more preferably 1:100 to 100:1.

[0150] Catalyst Passivation and Replacement:

[0151] The heterogeneous metal catalyst can lose activity or selectivity over periods of prolonged operation. Factors contributing to an activity loss are sintering, poisoning, fouling and coking, leaching, chemical transformation or mechanical degradation. Partially, the loss of activity or selectivity can be reversed or slowed by regeneration of the catalyst or optimization of the reaction conditions. But irrespective of measures taken to restore catalyst activity or selectivity or to slow the rate of catalyst deactivation, the replacement of catalyst will become inevitable, sooner or later during the course of regular operations. Replacement of catalyst usually requires shutting down and opening the reactor and exposing the catalyst to air or atmospheric conditions.

[0152] Besides catalyst replacements, there can be other events which require the catalyst to be exposed to air or atmospheric conditions. These events can be any maintenance or repair events which require opening of the reactor.

[0153] In the event of a replacement of the catalyst or any other event requiring the exposure of the catalyst to air or atmospheric conditions, the reactor needs to be partially shutdown, i.e. the mass flow rate of substrate msand the mass flow rate of hydrogen mH need to be reduced to zero.

[0154] According to the present invention, the mass flow rate of substrate msand the mass flow rate of hydrogen mH can be simultaneously or sequentially be reduced to zero.

[0155] In a preferred embodiment, the mass flow rate of substrate ms is reduced to zero before the mass flow rate of hydrogen mH is reduced to zero. Reducing the mass flow of substrate msto zero before reducing the mass flow rate of hydrogen mH may prevent unwanted side reactions of the substrate, such as oligomerization or polymerization which may occur by reaction of the formed products with excess substrate. In this preferred embodiment, the mass flow rate of hydrogen mH is reduced to zero after the mass flow rate msof substrate has been reduced to zero.

[0156] The flow rates of substrate msor hydrogen mH can be reduced to zero by closing the necessary valves and switches. The flow rates can be reduced abruptly or they can be reduced gradually over a period of time. In one preferred embodiment, the flow rates are reduced abruptly by closing the corresponding valves as quickly as the valves can be closed. In another embodiment, the flow rates are reduced to zero gradually, preferably constantly, over a period of time. The time period over which the flow rates are reduced usually depend on the initial mass flow rates and are usually in the range of 1 second to 10 minutes. If the mass flow rate of hydrogen mH is reduced to zero after reducing the mass flow rate of other substrate ms, the interval between the time at which the mass flow rate of substrate ms reaches zero and the time at which the flow rate of hydrogen reaches zero is typically 10 to 120 minutes, preferably 15 to 90 minutes and more preferably 20 to 60 minutes in an industrially scale process. Preferably, the mass flow rate of hydrogen is not stopped until all substrate has exited the reactors, which depends on the residence time of the reactor. The preferred time may also be derived from temperature measurements at those parts of the reactor which are close to the reactor outlet. The time at which the reactor temperature close to the reactor outlet begins to decrease gives an indication about the time it takes for the reactor to react to the stopped flow of substrate and to purge the substrate out of the reactor. The time at which the temperature of the reactor bottom begins to decrease is preferably the minimum time between reducing the mass flow rate of substrate ms to zero and the beginning of the reduction of the mass flow rate mH to zero. Preferably, the time between reducing the mass flow rate of substrate ms to zero and the beginning of the reduction of the mass flow rate mH to zero is preferably 5 to 60 minutes, more preferably 10 to 30 minutes longer than the time required to achieve the beginning of the decrease of the reactor temperature close to the outlet of the reactor.

[0157] In a preferred embodiment, ammonia is fed to the reactor and over the catalyst after the mass flow rate of hydrogen mH has been reduced to zero.

[0158] In a further preferred embodiment, the substrate is converted in the presence of ammonia at a mass flow rate of ammonia IT)NH3.

[0159] In a preferred embodiment, the mass flow rate of ammonia is continued during the reduction of the mass flow rates of substrate ms and hydrogen mH.

[0160] The mass flow rate of ammonia ITI’NHS after the reduction of the mass flow rates ms and mH can be the same or different to the flow rate of ammonia ITINH3 used during the reaction or during the reduction of the mass flow rates of substrate and hydrogen.

[0161] The mass flow rate of ammonia ITI’NHS after the reduction of the mass flow rates of substrate ms and hydrogen mH at which the catalyst is contacted with ammonia depends on the reactor size and geometry and is usually selected so that the weight hourly space velocity of ammonia is in the range of 0.1 to 100 kg NHsper kg catalyst per hour, preferably 0.5 to 50 kg NH3 per kg catalyst per hour and more preferably 1 to 10 kg NH3 per kg catalyst per hour.

[0162] The temperatures of the reactor at the point at which the mass flow rate of hydrogen mH and substrate ms have been reduced to zero and at which the catalyst is contacted with ammonia is preferably from 100 to 400°C, more preferably 120 to 300°C and even more preferably from 150 to 250°C, whereby the temperatures close to the outlet of the reactor are usually slightly lower than the temperatures close to the inlet of the reactor. The temperature difference between the inlet and the outlet is usually in the range between 1 to 50, preferably 5 to 40 and more preferably 10 to 30°C. The pressure in the reactor after stoppage of the mass flow rates of substrate ms and hydrogen mH and during contact with ammonia at the mass flow rate of m'NHa is usually in the range of 10 to 400 bar, preferably 20 to 300 bar and more preferably 25 to 280 bar.

[0163] Due to the stopped flow of hydrogen and substrate, the catalyst is passivated with ammonia. The passivation of the catalyst with ammonia has the advantage that the initial temperature increase is significantly less than the temperature increases experienced when passivating the catalyst with air. Typically, the temperature increase during passivation with ammonia is in the range of 0.5 to 25°C, preferably 1 to 20°C and preferably 2 to 15°C. These values are significantly lower than a temperature increase of more than 100°C or even more than 200°C or even more than 300°C experienced during passivation with air without prior passivation with ammonia.

[0164] The passivation of the catalyst with ammonia at the conditions set out above is preferably conducted for 5 minutes or more, preferably between 5 to 300 minutes, more preferably 20 to 180 minutes and even more preferably 30 to 120 minutes.

[0165] Ammonia is preferably used in a purity of 90 percent or more, more preferably 95 percent or more, even more preferably 98 percent or more and even more preferably 99 percent or more.

[0166] Ammonia is preferably in the liquid state when contacting the catalyst. When ammonia is in the liquid state, the heat capacity is comparably higher and the heat from the passivation with ammonia can be more effectively transported out of the reactor compared to direct passivation with an oxygeneous gas.

[0167] After passivation of the catalyst with ammonia it is preferred to conduct at least one of the following postpassivation steps:

[0168] - cooling of the reactor;

[0169] - purging the reactor; and

[0170] - contacting the catalyst with an oxygen comprising gas (oxygen passivation);

[0171] In one post-passivation step, the reactor is preferably cooled to temperatures at temperatures up to 100°C, preferably up to 75°, more preferably up to 60°C and more preferably up to 50 and most preferably up to 40°C. Cooling is preferably effected by dissipation of heat through the reactor walls. Cooling can also be effected by cooling the reactor mantle with a cooling medium, e.g. cooling water. In another post-passivation step, the reactor is preferably purged to remove residual ammonia from the surface of the catalyst. Purging is preferably carried out by contacting the catalyst with a purging fluid, in particularly an inert fluid, or hydrogen. The inert purging fluid is preferably nitrogen gas or a noble gas, such as neon, argon, xenon or krypton. More preferably, the purging fluid is hydrogen. The reactor is preferably purged with the purging fluid for 0.1 to 24 hours, preferably 0.25 to 18 hours and more preferably from 0.5 to 12 hours.

[0172] Further, in still another preferred post-passivation step, the catalyst is contacted with an oxygen comprising gas in order to achieve passivation with oxygen. Post-passivation of the catalyst passivated with oxygen has the advantage that more stable oxides are formed at the surface of the catalyst which make handling of the passivated catalyst even more safe. The catalyst is preferably contacted with an oxygen-comprising gas stream such as air or a mixture of air with nitrogen. The oxygenous gas may be used with additions of inert gases, such as nitrogen, helium, neon, argon or carbon dioxide. In a preferred embodiment, air is used together with nitrogen, where the proportion by volume of air is preferably in the range from 1% to 80%, more preferably 20% to 70% and especially preferably 30% to 60% by volume. In a preferred embodiment, the proportion by volume of air in the mixture with nitrogen is increased gradually from 0% to about 100% by volume, so that the concentration of oxygen in the oxygen comprising gas corresponds to the oxygen content of air. The increase of the proportion of air is usually carried out in a period of about 1 to 12 hours, preferably 1.5 to 6 and more preferably 2 to 4 hours. The post-passivation is effected preferably at temperatures up to 50°C, preferably up to 45°C and most preferably up to 35°C. The volume flow rate of oxygenous gas is preferably 1 liter per liter reactor volume to 100 liter per liter reactor volume, preferably 2 to 75 liter per liter reactor volume to 100 liter per liter reactor volume and more preferably 5 to 50 liter per liter reactor volume to 100 liter per liter reactor volume. Surprisingly, it was found that even in the post-passivation step with oxygen, the reactor temperature did not increase to the same extend the temperature would increase when the catalyst is directly passivated with oxygen, without ammonia passivation.

[0173] Preferably, all of the previously mentioned post-passivation steps are carried out after ammonia passivation, more preferably in the order of cooling, purging and oxygen-passivation.

[0174] After the nitrogen passivation and conducting the one or more post-passivation steps, the reactor is usually safe to open.

[0175] After opening the reactor, further steps can be taken of either replacing the catalyst or conducting other measures, such as cleaning, inspection, repairs, or maintenance.

[0176] Replacing the passivated catalyst usually comprises one or more of the following steps: removing the passivated catalysts, e.g. by vacuuming, scooping or dumping of the catalysts, collecting the passivated catalyst for collection and storage in appropriate containers for proper disposal or regeneration; inspection and cleaning of the reactor: before installing the new catalyst, the reactor is preferably inspected for any signs of damage, corrosion, or fouling. Any debris or deposits should be preferably removed, and the reactor surfaces should preferably be cleaned to ensure optimal contact between the new catalyst and the reactants; loading the new catalyst; installing or re-installing reactor internals; and closing the reactor.

[0177] After the replacement of the catalyst or conducting the event, that required exposing the catalyst with air, e.g. conducting inspection, cleaning, maintenance or repairs, the reactor is preferably restarted. Restart of the reactor preferably comprises the step of activation (if the catalyst is introduced in a passivated form) or reduction of the replaced catalyst (if the catalyst is introduced in its calcined form. Restarting the reactor further comprises bringing back the reactor to operating conditions by reintroducing the substrates and optionally heat supply and bringing back other process parameters to the operating conditions.

[0178] A second aspect of the invention comprises a process for the passivating a heterogenous metal catalyst, suitable for converting one or more substrates with the heterogenous metal catalyst in the presence hydrogen and optionally in the presence of ammonia to form at least one chemical product, comprising the steps of: a) stopping any flow of substrate and / or hydrogen over the catalyst; b) contacting the catalyst with ammonia at a mass floss m

[0179] The passivation process of the second aspect of the present invention comprises a first step of: a) stopping any flow of substrate and / or hydrogen over the heterogenous metal catalyst. The flow of substrate and / or hydrogen can be stopped as described above.

[0180] In a second step b), the heterogenous metal catalyst is contacted with ammonia at a mass floss ITINH3. The contacting of the heterogenous metal catalyst with ammonia can be carried out as described above. After passivation of the catalyst with ammonia it is preferred to conduct at least one of the following postpassivation steps:

[0181] - cooling of the reactor;

[0182] - purging the reactor; and

[0183] - contacting the catalyst with oxygen (oxygen passivation). These steps can also be performed as described above.

[0184] In a third aspect, the present invention relates to the use of ammonia for passivating a heterogeneous metal catalyst prior to an event which requires contacting the heterogenous metal catalyst with air. Contacting and passivating a heterogenous metal catalyst can be performed at described above. Events which require contacting a heterogenous metal catalyst with air a preferably cleaning, inspection, repairs or maintenance of the chemical reactor in which the heterogeneous catalyst is comprised in. Another preferred event usually requiring contacting a heterogenous catalyst with air is the exchange or replacement of the heterogenous catalyst in a chemical reactor.

[0185] The process of preparing a chemical product according to the invention and the process of passivating a heterogenous metal catalyst according to the invention involve a step where the heterogenous metal catalyst is essentially passivated with ammonia. Surprising it was found that passivation with ammonia results in a significantly lower temperature increase in the reactor. Decreasing the temperature or avoiding temperature spikes can prevent sintering of the catalyst or structural changes in parts of the catalyst, e.g., the support material. Such changes normally would normally lead to the deterioration of catalysts properties, such as activity or selectivity. Passivation of a heterogenous catalyst with ammonia allows for safe-handling of the catalyst during events requiring a shut-down of the reactors, such as cleaning, inspection, repairs or maintenance and increases the time a reactor is available for performing the desired reactions. The benefits or the present invention are demonstrated in the following examples:

[0186] Inventive Example:

[0187] The substrate ethylene glycol (MEG) was aminated with ammonia in the presence of hydrogen and a heterogenous catalyst comprising mainly Co, Ni and Cu as active components. The volume of the fixed bed reactor was 5.5 1 (6.8 kg).

[0188] The flow rate of MEG was approximately 3.5 kg / hr.

[0189] MEG was fed to a fixed bed reactor at a feed temperature of 180°C.

[0190] The flow rate of ammonia was approximately 10 kg / hr.

[0191] Ammonia was fed at a feed temperature of 180°C.

[0192] The flow rate of hydrogen was approximately 200 g / hr

[0193] The reactor temperature close to the feed inlet was approx. 180°C, whereas the temperature closest to the reactor outlet was approx. 191°C.

[0194] The MEG-feed was closed, while both hydrogen and ammonia were continued to be fed.

[0195] Approximately 20 minutes after shutting down the MEG-feed, the reactor temperatures began to decrease, indicating that MEG was being flushed out of the reactor and the exothermic amination reaction had ceased.

[0196] The hydrogen feed was closed 35 minutes later, while ammonia (purity of >99%) was still being fed at its feed temperatures.

[0197] The residence time of the MEG substrate in the reactor was less than five minutes (plug flow). Thus, when the hydrogen feed was closed, the reactor contained no more MEG.

[0198] Approximately 92 minutes after the stop of the MEG flow, the ammonia flow was stopped, and the reactor was allowed to cool to approximately 40°C.

[0199] After reaching a reactor temperature of about 40°C, remaining ammonia was mostly purged with nitrogen and then an air feed was opened with an uninterrupted flow of 40 l / h and increased to 60 l / h 43 minutes later.

[0200] The first temperature in the catalyst bed increased from 40°C to 53°C approximately 15 minutes after opening the air flow. The last temperature in the catalyst bed increased only to a slightly higher maximum value of 60°C.

[0201] Comparative example:

[0202] The MEG feed was shut while the reactor still was hot. Then the reactor was cooled down to 40°C while continuing the flow of NH3 and hydrogen. Then the reactor contents were purged with a continuous flow of 200 g / h of nitrogen. Once the reactor contained only nitrogen, a small impulse of air was fed by opening and immediately afterwards closing a feeding valve. During this impulse 50 g / h of air were fed together with the 200 g / h nitrogen into the reactor for 2 minutes. One minute later a sharp increase of the next downstream temperature was observed, reaching a peak over 200 °C. Due to the sharp temperature increase, the air feed was immediately shut again. The air was thereafter opened several times for a short period of time, which each time led to sharp temperature spikes of up to 250 °C downstream of the reactor. The procedure had to be repeated several times with short air feed impulses for a prolonged period of time so that no excessive temperature peaks would be reached (the oxidation reaction enthalpy can cause a meltdown of the metallic catalyst mass). This passivating procedure demanded about 24 hours of time.

[0203] It can be seen that even though significantly less air was used for contacting the catalyst which was not previously passivated with hot ammonia without hydrogen, the temperature spiked from 40°C to more than 200°C. The catalyst which was passivated with hot ammonia without hydrogen in the example according to the invention only showed a marginal temperature increase of less than 20°C.

Claims

Claims1. Process for preparing a chemical product by reacting at least one substrate in a reactor or a series of reactors in the presence of hydrogen, a heterogenous metal catalyst and optionally ammonia to form at least one chemical product, the at least one substrate being introduced into the reactor or the series of reactors with a mass flow msand hydrogen being introduced into the reactor or the series of reactors with a mass flow mH, and optional ammonia is introduced at a flow rate ITINHS, wherein the event of (I) a replacement of the catalyst in the reactor or the series of reactors or (II) another event where the catalyst needs to be exposed to air, the mass flow ms and IT)H2 is reduced to zero and ammonia is introduced or continued to be introduced into the reactor or series of reactors at a mass flow m and brought into contact with the catalyst.

2. Process for the passivating a heterogenous metal catalyst, suitable for converting one or more substrates with the heterogenous metal catalyst in the presence hydrogen and optionally in the presence of ammonia to form at least one chemical product, comprising the steps of: a) stopping any flow of substrate and / or hydrogen over the catalyst; b) contacting the catalyst with ammonia at a mass flow m .

3. A process according to claim 1 or claim 2, wherein the at least some metal comprised in the heterogenous metal catalyst is in the oxidation state zero.

4. A process according to at least one of claims 1 to claim 3, wherein the catalyst is contacted with essentially pure ammonia.

5. A process according to at least one of claims 1 to 4, wherein the catalyst is contacted with ammonia at an absolute pressure in the range of 1 to 400 bar.

6. A process according to at least one claims 1 to 5, wherein the catalyst is contacted with ammonia at a temperature in the range of 100 to 400°C.

7. A process according to at least one of claims 1 to 6, wherein the flow rate of ammonia ITI'NHS is in the range of 0.1 to 10 kg / h per kg catalyst.

8. A process according to at least one of claims 1 to 7, wherein the contact time of the catalyst with ammonia is in the range of 5 to 300 minutes.

9. A process according to at least one of claims 1 to 8, wherein after stopping the ammonia mass flow ITI'NH3, the catalyst is contacted with an oxygen-comprising gas.

10. A process according to claim 9, wherein the catalyst is contacted with a mixture of nitrogen and oxygen.

11. A process according to claim 10 wherein the concentration of oxygen in the mixture of nitrogen and air is increased until the ratio of oxygen to nitrogen corresponds to the composition of air.

12. A process according to one claims 9 to 11, wherein contacting the catalyst with the oxygen comprising gas occurs at a temperature in the range of 25 to 100°C.

13. A process according to according to one of claims 9 to 12 wherein the flow rate of the oxygencomprising gas is in the range of 1 to 100 g / h per kg catalyst.

14. A process according to one of claims 8 to 13, wherein contacting the catalyst with oxygen occurs for a period of 5 minutes or more.

15. A process according to at least one of claims 1 to 14, wherein the catalyst comprises one or more active metals selected from the metals and semi-metals of groups 1 to 6 and 12 to 17 of the periodic table of elements.16 A process according to claiml 5, wherein the one or more active metals are selected from the group consisting of Co, Ni and Fe.

17. A process according to at least one of claims 1 to 14, wherein the catalyst does not comprise zeolites.

17. A process according to at least of one claims 1 to 16, wherein the substrates converted in the presence of the catalyst comprise at least one functional group selected from the group comprising a nitrile functional group, a hydroxyl functional group, an aldehyde functional group or a keto functional group or a double (ethylenic) or triple (acetylenic) (unsaturated) carbon-carbon bond.

18. A process according to at least one claims 1 to 17, wherein the substrate is converted in the presence of ammonia.

19. A process according to claims 17 and / or 18, wherein the chemical product is an amine.

20. A process according to claim 19, wherein the temperature is 120 °C or higher.

21. Use of ammonia for passivating a heterogeneous metal catalyst prior to an event which requires contacting the heterogenous metal catalyst with air.