EP2046721A1

EP2046721A1 - Direct amination of hydrocarbons

Info

Publication number: EP2046721A1
Application number: EP07787621A
Authority: EP
Inventors: Joachim-Thierry Anders; Johann-Peter Melder; Petr Kubanek; Ekkehard Schwab; Wolfgang Mackenroth; Karl HÖLEMANN; Frederik Van Laar
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2006-07-21
Filing date: 2007-07-17
Publication date: 2009-04-15
Also published as: KR20090031623A; JP2009544651A; US20090292144A1; CN101489978A; WO2008009668A1

Abstract

Disclosed is a method for aminating hydrocarbons with ammonia. Said method is characterized in that the amination process is carried out in the presence of an additive which reacts with hydrogen. At least one organic-chemical compound, N<SUB>2</SUB>O, hydroxylamine, hydrazine, and/or carbon monoxide is/are used as an additive.

Description

Directamination of hydrocarbons

description

The invention relates to a process for the preferably continuous amination, preferably direct amination of hydrocarbons, preferably by reacting hydrocarbons, more preferably aromatic hydrocarbons, in particular benzene, with ammonia, preferably in the presence of catalysts which catalyze the amination, wherein the amination in the presence of a Performs additional, which reacts with hydrogen, being used as an additive at least one organic chemical compound, N2O, hydroxylamine, hydrazine and / or carbon monoxide. The term "additive" in this document means one or more additives which react with hydrogen or "hydrogen-reactive additive" which is to be understood below as meaning both organic-chemical compounds and carbon monoxide. The additive is preferably nitrobenzene.

In particular, the invention relates to processes for the amination of hydrocarbons, preferably by reaction of aromatic hydrocarbons, more preferably benzene with ammonia, in particular according to the following reaction, which is preferably catalysed:

Reaction equation 1

The commercial production of amines, in particular of aromatic amines, such as aniline, is usually carried out in multistage reactions. For example, aniline is usually prepared by conversion of benzene to a benzene derivative, e.g. As nitrobenzene, chlorobenzene or phenol and subsequent conversion of this derivative into aniline.

More advantageous than such indirect processes for the preparation of particular aromatic amines are methods which allow direct preparation of the amines from the corresponding hydrocarbons. A very elegant route is the heterogeneously catalyzed direct amination of benzene, first described in 1917 by Wibaut (reports, 50, 541-546). Since direct lamination is equilibrium-limited, several systems have been described which shift the equilibrium limitation by the selective removal of hydrogen from the reaction and allow increased benzene conversion. Most processes are based on the use of metal oxides, which are reduced by hydrogen, so that remove the hydrogen from the reaction system and thus shift the balance.

CN 1555921 A discloses the oxidoamination of benzene in the liquid phase, wherein hydrogen peroxide functions as the "O" donor, but the use of H2O2 is only of limited suitability due to the price and the low selectivity due to secondary reactions for bulk chemicals.

CA 553,988 discloses a process for the production of aniline from benzene wherein benzene, ammonia and gaseous oxygen are reacted at a temperature of about 1000 ^° C. on a platinum catalyst. Suitable platinum-containing catalysts are platinum alone, platinum with certain specific metals and platinum together with certain specific metal oxides. Furthermore, in CA 553,988 a process for the preparation of aniline is disclosed wherein benzene in the gas phase with ammonia niak is reacted in the presence of a reducible metal oxide at temperatures of 100 to 1000 ⁰ C, without the addition of gaseous oxygen. Suitable reducible metal oxides are the oxides of iron, nickel, cobalt, tin, antimony, bismuth and copper.

No. 3,919,155 relates to the direct amination of aromatic hydrocarbons with ammonia, wherein the catalyst used is nickel / nickel oxide, wherein the catalyst additionally contains oxides and carbonates of zirconium, strontium, barium, calcium, magnesium, zinc, iron, titanium, aluminum, silicon, cerium, Thorium, uranium and alkali metals may contain.

US 3,929,889 also relates to the direct amination of aromatic hydrocarbons with ammonia on a nickel / nickel oxide catalyst, wherein the catalyst used was partially reduced to elemental nickel and subsequently reoxidized to yield a catalyst having a nickel: nickel oxide ratio of 0.001: 1 to 10: 1.

No. 4,001,260 discloses a process for the direct amination of aromatic hydrocarbons with ammonia, again using a nickel / nickel oxide catalyst which has been applied to zirconium dioxide and has been reduced with ammonia before use in the amination reaction.

No. 4,031,106 again relates to the direct amination of aromatic hydrocarbons with ammonia on a nickel / nickel oxide catalyst on a zirconia support, which further contains an oxide selected from lanthanides and rare earth metals. DE 196 34 1 10 describes the non-oxidative amination at a pressure of 10 - 500 bar and a temperature of 50 - 900 ⁰ C, wherein the reaction takes place in the presence of an acidic heterogeneous catalyst which is modified with light and heavy platinum metals.

WO 00/09473 describes a process for the preparation of amines by direct amination of aromatic hydrocarbons on a catalyst containing at least one vanadium oxide.

WO 99/10311 teaches a process for the direct amination of aromatic hydrocarbons at a temperature of <500 ⁰ C and a pressure of <10 bar. The catalyst used is a catalyst comprising at least one metal selected from transition metals, lanthanides and actinides, preferably Cu, Pt, V, Rh and Pd. The direct amination is preferably carried out to increase the selectivity and / or the conversion in the presence of an oxidizing agent. The oxidizing agent is preferably an oxygen-containing gas, e.g. As air, 02-enriched air, 02 / inert gas mixtures or pure oxygen.

WO 00/69804 relates to a process for the direct amination of aromatic hydrocarbons, wherein the catalyst used is a complex comprising a noble metal and a reducible metal oxide. Catalysts containing palladium and nickel oxide or palladium and cobalt oxide are particularly preferred.

Indirect syntheses are further disclosed in CN 1424304, CN 1458140 and WO 2004/052833.

Most of the methods mentioned are based on a mechanism for direct lamination, as listed in the summary of WO 00/69804. Thereafter, the (noble) metal-catalyzed preparation of the desired amine compound from the aromatic hydrocarbon and ammonia and, in a second step, the "trapping" of the hydrogen formed in the first step with a reducible metal oxide are carried out The same mechanistic considerations apply to the process in WO 00 / 09473, in which the hydrogen is trapped with oxygen from vanadium oxides (page 1, lines 30 to 33) The same mechanism is also used in US 4,001, 260, as in the comments and the illustration in column 2, lines 16 to 44 can be seen.

The object of the present invention is to develop a particularly economical process for the amination of hydrocarbons, in particular processes for the reaction of benzene with ammonia, in which a preferably continuous process with the highest possible selectivity and / or highest possible conversion is made possible. This object is achieved by the method described above.

It has surprisingly been found that the addition of an organic chemical substance which reacts with hydrogen and / or carbon monoxide, preferably in the feed, with the same selectivity of the conversion to the desired product could be increased.

Thus, for example, in the direct amination of benzene with ammonia (according to reaction equation 1 on page 1) aniline is formed, but at the same time one mole of hydrogen is formed. Furthermore, hydrogen may also be present in the reaction vessel as a result of the decomposition of ammonia. According to the technical teachings of the prior art, ammonia, for example, is decomposed significantly into hydrogen and nitrogen with the nickel-nickel oxide systems.

Regardless of the source of hydrogen, it limits the turnover of the direct amination reaction. Since the reaction shown in reaction equation 1 is an equilibrium reaction, the quotient of the product of the concentrations or partial pressures of the products and those of the reactants is a constant, see textbooks of physical chemistry: Peter Atkins; JuNo de Paula, Atkins' Physical Chemistry, ^8th edition, Oxford: Oxford University Press, 2006, ISBN

0-19-870072-5 or Gerd Wedler, Textbook of Physical Chemistry, 5th, completely revised and updated edition, Weinheim: Wiley-VCH, 2004, ISBN 3-527-31066-5). Therefore, a high concentration of hydrogen causes a lower conversion of benzene to aniline. Conversely, in particular in addition to the reaction system passing hydrogen, z. B. from the decomposition of ammonia, affect the equilibrium of the reaction and push back to the reactant side, d. H. even a cleavage of aniline in the educts benzene and ammonia effect.

It is therefore advantageous to minimize the hydrogen concentration in the reaction system.

It is particularly advantageous if one or more organic-chemical substance (s) and / or carbon monoxide is used to minimize the hydrogen concentration instead of the metered addition of oxygen (WO 99/1031 1) or hydrogen peroxide (CN 1555921) cited in the prior art is selected as an addition. In particular, it is advantageous to choose exactly that organic chemical substance which, upon reaction with the hydrogen present in the system, simultaneously forms the same reaction product which is also formed in the direct laminating reaction.

The process according to the invention removes hydrogen from the reaction system, both from the direct amination reaction and from the ammonia decomposition, and reduces the repression of the equilibrium on the side of the starting materials or prevented, ie it is increased by reducing the proportion of hydrogen in equilibrium even the conversion of Direktamination reaction. The reduction of the hydrogen concentration in the reaction mixture has a direct influence on the conversion to the desired product, since directamination is an equilibrium reaction.

In a particularly preferred embodiment of the process, the hydrogen is used productively by additional product of value being produced by the hydrogenation of the additive into the feed. The reaction of hydrogen with the organic chemical additive, if it is an additive that reacts with hydrogen to the same product as the hydrocarbon in the Direktaminierung, also introduced no foreign product in the sense of a co-production - that is, that the Separation of the hydrogen scavenging product from Direktaminierungsprodukt deleted and therefore the cost of working up the reaction product is significantly reduced. This very elegant solution not only shifts the balance, it also uses the unwanted by-product to produce the desired value product.

In a further preferred embodiment of the process, the organic chemical additive reacts with hydrogen to form one of the educts.

The addition of organic chemical additives is advantageous over the prior art. In most of the abovementioned publications, metal oxides are used as catalysts or catalase reactants. If only the oxygen from these catalysts or catalytic reactants is to remove the hydrogen from the system, this implicitly has the disadvantage that the catalysts or catalyst reactants quickly deactivate because the oxygen contained is due both to the hydrogen formed in the direct amination reaction as is also wegreduziert by the liberated in the ammonia fission hydrogen. In addition, more metal centers of the oxidation state (0) are present on the reduced catalysts or catalyst reactants, which according to experience further increase the decomposition of ammonia, which further accelerates the deactivation of the catalysts or catalytic reactants and requires earlier regeneration of the catalysts or catalase reactants - with corresponding effects on the economic viability of the process. The addition of oxygen is inferior to the use of organic chemical substances, because this can be done on the catalytically active metal surfaces to a considerable extent total combustion of the organic components of the reaction system to CO2, again with significant effects on the efficiency of the process. The addition of hydrogen peroxide is disadvantaged because of lower selectivity compared to the inventive method. All of these disadvantages can be overcome by the method according to the invention without the pressure or temperature having to be changed significantly.

The additives used in the process according to the invention can react with hydrogen. Preferably, it is organic chemical substances that can react with hydrogen. Particularly preferred are organic chemical substances which form the same reaction product in the reaction with hydrogen, which is also formed in the direct amination of hydrocarbons.

Particularly preferred is the direct amination of benzene with ammonia to aniline, the particularly preferred organic-chemical additive also forms aniline in the reaction with hydrogen, more preferably, the organic chemical additive is nitrobenzene.

In a further preferred embodiment of the process is in the direct amination of hydrocarbons, preferably the direct amination of benzene with ammonia to aniline, the organic chemical additive used N2O, hydroxylamine and / or hydrazine.

The advantage that the value product is formed when using nitrobenzene with reaction with hydrogen, while not true when using hydroxylamine or hydrazine as a hydrogen scavenger. However, when using hydroxylamine or hydrazine as a hydrogen scavenger by the reaction with hydrogen releases ammonia, thus one of the starting materials, which is also preferred because thermodynamically the formation of aniline is promoted in equilibrium with increasing ammonia excess, in addition, the balance is move to aniline as the hydrogen content decreases.

The organic chemical additives that react with hydrogen may be, but are not limited to, oxidants known as such. Rather, all molecules with reducible functionalities are suitable as organic-chemical additives, in particular those which contain multiple bonds. Preferably, these molecules or the products of their reaction with hydrogen should preferably not react directly with the hydrocarbon because this would interfere with the selectivity of the direct amination.

In addition to nitrobenzene are, for example, carbon monoxide, carbonyl compounds, nitriles, imines, amides, nitro compounds, nitroso compounds, olefins, alkynes, organic peroxides, organic acids, organic acid derivatives, hydrazine derivatives, hydroxylamines, quinones, aromatics, molecules with sp2-hybridized carbon atoms, as well as all others Molecules with reducible functionalities, in particular those which contain multiple bonds or combinations thereof, for use in the inventive method into consideration.

Examples of individual examples of organic-chemical additives according to the invention selected from the abovementioned substance groups (exemplary and not limiting the scope of the invention) are nitrobenzene, carbon monoxide, hydrocyanic acid, acetonitrile, propionitrile, butyronitrile, benzonitrile, imines from the reaction of benzaldehyde with ammonia or primary amines, imines from the reaction of aliphatic aldehydes with ammonia or primary amines, formamide, acetamide, benzamide, nitrosobenzene, ethene, propene, 1-butene, 2-butene, isobutene, n-pentene and pentene isomers, Cyclopentene, n-hexene, hexene isomers, cyclohexene, n-heptene, heptenoisomeres, cycloheptene, n-octene, octadiene, cyclooctene, cyclooctadiene, acetylene, propyne, butyne, phenylacetylene, meta-chloroperbenzoic acid, formic acid, acetic acid, propionic acid, butyric acid, Valeric acid, caproic acid, oxalic acid, malonic acid, succinic acid, maleic acid, fumaric acid, esters or anhydrides of said carboxylic acid n, hydrazine, phenylhydrazine, hydrazides of aliphatic or aromatic ketones, hydroxylamine, alkylhydroxylamines and arylhydroxylamines (or combinations of said substances).

Particular preference may be given in particular to reducible nitrogen-containing compounds such as nitriles, nitro compounds, nitroso compounds, and amides, and also acetylene and short-chain alkynes, preferably having 3 to 6 carbon atoms, and short-chain olefins, preferably having 2 to 6 carbon atoms, or combinations thereof for this purpose ,

Very particular preference may be given to choosing nitrobenzene, nitrosobenzene, carbon monoxide, acetylene, ethene, propene, hydrazine, phenylhydrazine, hydroxylamine, phenylhydroxylamine, acetonitrile, benzonitrile or combinations thereof for the process according to the invention as organic-chemical additives.

• The addition of the additive, which reacts with hydrogen, can take place anywhere in the process. Possible examples include the separate supply of hydrocarbon, preferably benzene, amine, preferably ammonia, and organic chemical additive, preferably nitrobenzene, in the reactor,

The combined supply of hydrocarbon, preferably benzene, and organic chemical additive, preferably nitrobenzene, in a common feed line, separate from the amine, preferably ammonia, into the reactor, The common supply of amine, preferably ammonia, and organic chemical additive, preferably nitrobenzene, in a common feed line, separate from the hydrocarbon, preferably benzene, into the reactor,

• the supply of the individual components at different points in the reactor

(eg, one or more of the three components at the reactor inlet, one just above or into the catalyst bed).

Preferably, the dosage of the additive which reacts with hydrogen, together with the hydrocarbon, preferably benzene, at the input of the reactor. Very particular preference is given to metering a nitrobenzene / benzene mixture in a common feed line and ammonia in another feed line, in each case at the inlet of the reactor. Likewise, it is very preferable to first combine the metering of a nitrobenzene / benzene mixture in a common feed line and the metering of the ammonia from a second feed line in a mixer or evaporator in order to supply a homogeneous mixture to the catalyst bed.

The hydrocarbon / organic chemical additive molar ratio can be chosen in a very wide range, since even small additions are effective, but even higher additions are not detrimental. The molar ratio of hydrocarbon to organic chemical additive can thus be varied within a range of 10000: 1 to 1: 1000.

It is advantageous, however, to add a smaller amount of hydrogen scavenger, z. B between 0.001 wt .-% and 50 wt .-%, based on the total weight of the hydrocarbon used and the additive which reacts with hydrogen.

Thus, the weight fraction of the additive which reacts with hydrogen is particularly preferably between 0.001% by weight and 50% by weight, in particular between 0.1% by weight and 15% by weight, very particularly preferably between 0.5 Wt .-% and 3 wt .-%, in each case based on the total weight of the hydrocarbon used, preferably benzene, and the additive, preferably nitrobenzene, wherein in the process of direct amination of benzene preferably a mixture of benzene and nitrobenzene is used as aromatics.

Analogous to the procedure for nitrobenzene, it is also possible to use a hydrogen scavenger when using hydroxylamine or hydrazine. The o. G. preferred proportions by weight, based on the benzene feed, preferably also apply to these substances.

All other reaction conditions can be selected according to the prior art. Is preferably conducted at temperatures between 300 ⁰ C and 500 ⁰ C gearbei- tet, more preferably between 350 and 400 ⁰ C. The reaction pressure is usually between 1 and 1000 bar, preferably between 2 and 300 bar, more preferably between 2 and 150 bar.

It is thus a further advantage of the process according to the invention that no changes in the reaction conditions of Direktamination are required compared to the work without organic chemical additive (including hydroxylamine, N2O, hydrazine and carbon monoxide).

As catalysts, the catalysts known for the direct amination of hydrocarbons, in particular those known for the direct amination of benzene with ammonia to aniline can be used. Such catalysts are widely described in the patent literature and well known. As catalysts, for example, conventional metal catalysts in question, for. As those based on nickel, iron, cobalt, copper, precious metals or alloys of these metals. As precious metals (EM), all precious metals may be considered, for. As Ru, Rh, Pd, Ag, Ir, Pt and Au, wherein the noble metals Ru and Rh are preferably not used alone, but in alloy with other transition metals, such as Co, Cu, Fe and nickel or mixtures thereof. Such alloys are also preferably used when using the other noble metals, for example, supported NiCuEM, Co-CuEM, NiCoCuEM, NiMoEM, NiCrEM, NiReEM, CoMoEM, CoCrEM, CoReEM, Fe-CuEM, FeCoCuEM, FeMoEM, FeReEM alloys of interest EM is a noble metal, especially preferably Ag and / or Au.

The catalyst may be in a generally conventional form, e.g. B. can be used as a powder or as usable in a fixed bed system (such as strands, spheres, tablets, rings), wherein the catalytically active ingredients may optionally be present on a support material. As a carrier material z. As inorganic oxides, such as ZrÜ2, SiÜ2, Al2O3, TiÜ2, B2O3, ThÜ2, CeÜ2, Y2O3 and mixtures of these oxides, preferably TiÜ2, ZrÜ2, Al2O3 and SiÜ2, more preferably ZrÜ2 in question. Under ZrÜ2 is meant both pure ZrÜ2 and the normal Hf-containing ZrÜ2.

Particularly preferably, the catalyst used catalyzes both the direct amination of the hydrocarbons and the hydrogenation of the organic chemical additive (including carbon monoxide), so that no further catalyst is needed for the hydrogenation of the additive.

The catalysts preferably used in the process according to the invention can be regenerated, for. By passing a reductive (e.g., -A atmosphere) over the catalyst or by first passing an oxidative and then a reductive atmosphere over or through the catalyst bed. The catalyst may be in both its reduced and oxidized form, preferably in its oxidized form.

Preference is given to using as catalyst a compound which contains one or more elements selected from the group consisting of Ni, Cu, Fe, Co, preferably in combination with Mo or Ag, where the elements can each be present in reduced and / or oxidized form. Particularly preferred catalysts are the combinations Co-Cu, Ni-Cu and / or Fe-Cu, in particular their combinations with additional doping element Ni-Cu-X, Fe-Cu-X, Co-Cu-X where X is Ag or Mo represents. Especially preferred are alloys of NiCu (Ag or Mo) and / or FeCu (Ag or Mo).

Preferably, in the catalyst, the weight fraction of the elements is Ni, Co and Fe together, d. H. the proportion of the total weight of these elements, where not all elements must be present in the catalyst, is between 0.1% by weight and 75%

Wt .-%, more preferably between 1 wt .-% and 70 wt .-%, in particular between 2 wt .-% and 50 wt .-% and the weight fraction of Cu between 0.1 wt .-% and 75 wt. -%, preferably between 0.1 wt .-% and 25 wt .-%, more preferably between 0.1 wt .-% and 20 wt .-%, in particular between 2.5 wt .-% and 10 wt. %, based on the total weight of the catalyst. In addition, the catalyst may contain carrier material.

The proportion by weight of doping element X in the total weight of the catalyst is preferably between 0.01% by weight and 8% by weight, more preferably between 0.1% by weight and 5% by weight, in particular between 0, 5% by weight and 4% by weight.

Preferably, one can activate the catalyst before its use in the process. Such activation, which preferably takes place at a temperature between 200 and 600 ^° C., particularly preferably at temperatures between 250 and 500 ^° C., in particular at temperatures between 280 and 400 ^° C., is preferably carried out with a mixture comprising inert gas and hydrogen or ammonia , In this case, the activation gas may contain other compounds. Activation reduces metal oxides to metal.

Furthermore, as catalysts, compounds containing Cu, Fe, Ni or mixtures thereof, which are supported on layered double-hydroxide (LDH) or LDH-like compounds. Preferably, magnesium-aluminum oxide obtainable by calcination of LDH or LDH-like compounds is used as a carrier. A suitable process for preparing magnesium-aluminum oxide comprising the step of calcining LDH or LDH-like compounds is, for example, in Catal. Today 1991, 11, 173 or in "Comprehensive Su- pramolecular chemistry ", (Ed. Alberti, Bein), Pergamon, NY, 1996, VoI 7,251.

In one embodiment of the process according to the invention, the catalyst used is particularly preferably a compound which contains one or more compounds selected from the group consisting of Ni, Cu, Co, Fe and Mo, these elements being able to be present in one or more oxidation states, preferably zirconium oxide and / or magnesium-aluminum oxide as a carrier.

In this embodiment, it is very particularly preferable to use as catalyst at least one of the following compounds (a), (b), (c) and / or (d):

(a) containing, preferably consisting of NiO, CuO and MoO 3 on zirconium oxide as support,

(b) (preferably mainly) containing NiO, CuO and CoO on zirconium oxide as support,

(C) containing, preferably consisting of NiO and / or CuO and / or Fe2Ü3 on

Zirconium oxide as a carrier

(d) containing, preferably consisting of NiO and / or CuO and / or Fe2Ü3 on

Magnesium aluminum oxide as a carrier,

wherein the catalysts (a) to (d) can be used singly or in combination with each other.

The catalysts need not necessarily contain NiO in order to carry out the Direktaminierung of hydrocarbons described herein according to the invention, but are often catalysts with NiO content in the performance for Direktamination superior to those without NiO.

For suitable catalysts, examples which do not limit the scope of the invention are already described in the literature.

For example, suitable catalysts according to (a), the catalytically active material 20 to 85 wt .-% oxygen-containing compounds of zirconium, calculated as ZrÜ2, 1 to 30 wt .-% oxygen-containing compounds of copper, calculated as CuO, 30 to 70 wt. % oxygen-containing compounds of nickel, calculated as NiO, 0.1 to 5 wt .-% oxygen-containing compounds of molybdenum, calculated as Moθ3, and 0 to 10 wt .-% oxygen-containing compounds of aluminum and / or Manganese, calculated as AI2O3 or Mnθ2 contains, inter alia, in DE-A 44 28 004 described (see Example 1).

For example, suitable catalysts according to (b), the catalytically active material 22 to 45 wt .-% oxygen-containing compounds of zirconium, calculated as ZrÜ2, 1 to 30 wt .-% oxygen-containing compounds of copper, calculated as CuO, 5 to 50 wt. % of oxygen-containing compounds of nickel, calculated as NiO, 5 to 50% by weight of oxygen-containing compounds of cobalt, calculated as CoO, 0 to 5% by weight of oxygen-containing compounds of molybdenum, calculated as MoO 3, and 0 to 10% by weight. % oxygen-containing compounds of aluminum and / or manganese, calculated as Al2O3 or MnO2, contains, inter alia in EP 1 106 600.

Also in EP 963 975 catalysts are described according to (b), see Example 3.

With the amination process according to the invention, it is possible to amines any hydrocarbons, such as aromatic hydrocarbons, aliphatic hydrocarbons and cycloaliphatic hydrocarbons, which can be arbitrarily substituted and can have heteroatoms and double or triple bonds within their chain or their ring (s). Aromatic hydrocarbons and heteroaromatic hydrocarbons are preferably used in the amination process according to the invention. The corresponding products are the corresponding arylamines or heteroarylamines.

For the purposes of the present invention, an aromatic hydrocarbon is to be understood as meaning an unsaturated cyclic hydrocarbon which has one or more rings and contains exclusively aromatic C-H bonds. Preferably, the aromatic hydrocarbon has one or more 5- or 6-membered rings.

By a heteroaromatic hydrocarbon are meant those aromatic hydrocarbons in which one or more of the carbon atoms of the aromatic ring is replaced by a heteroatom selected from N, O and S.

The aromatic hydrocarbons or the heteroaromatic hydrocarbons may be substituted or unsubstituted. By a substituted aromatic or heteroaromatic hydrocarbon are meant compounds in which one or more hydrogen atoms bound to one carbon or heteroatom of the aromatic ring is / are replaced by another. Such radicals are, for example, substituted or unsubstituted alkyl, alkenyl,

Alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl, cycloalkyl and / or cycloalkynyl radicals. Furthermore, the following radicals are suitable: halogen, hydroxy, alkoxy, Aryloxy, amino, amido, thio and phosphino. Preferred radicals of the aromatic or heteroaromatic hydrocarbons are selected from C 1-6 -alkyl, C 1-6 -alkenyl, C 1-6 -alkynyl, C 3-8 -cycloalkyl, C 3-8 -cycloalkenyl, alkoxy, aryloxy, amino and amido, where the term Ci-β refers to the number of carbon atoms in the main chain of the alkyl radical, the alkenyl radical or the alkynyl radical and the designation C3-8 to the number of carbon atoms of the cycloalkyl or cycloalkenyl ring. It is also possible that the substituents (radicals) of the substituted aromatic or heteroaromatic hydrocarbon have further substituents.

The number of substituents (radicals) of the aromatic or heteroaromatic hydrocarbon is arbitrary. In a preferred embodiment, however, the aromatic or heteroaromatic hydrocarbon has at least one hydrogen atom bonded directly to a carbon atom or a heteroatom of the aromatic ring. Thus, a 6-membered ring preferably has 5 or fewer substituents (residues) and a 5-membered ring preferably has 4 or fewer substituents (residues). Particularly preferably, a 6-membered aromatic or heteroaromatic ring carries 4 or fewer substituents, very particularly preferably 3 or fewer substituents (radicals). A 5-membered aromatic or heteroaromatic ring preferably carries 3 or fewer radicals, more preferably 2 or fewer radicals.

In a particularly preferred embodiment of the process according to the invention, an aromatic or heteroaromatic hydrocarbon of the general formula

[A) - [B) _n

used, in which the symbols have the following meaning:

A is independently aryl or heteroaryl, A is preferably selected from among phenyl, diphenyl, diphenylmethane, benzyl, dibenzyl, naphthyl, anthracene, pyridyl and quinoline.

nn;

n is a number from 0 to 5, preferably 0 to 4, especially in the case when A is a 6-membered aryl or heteroaryl ring; in the case where A is a 5-membered aryl or heteroaryl ring, n is preferably 0 to 4; independently of the ring size, n is more preferably 0 to 3, most preferably 0 to 2 and especially 0 to 1; the other hydrocarbon substituents or heteroatoms of A carrying no substituents B carry hydrogen atoms or optionally no substituents;

B is independently selected from the group consisting of alkyl, alkenyl, alkynyl, substituted alkyl, substituted alkenyl, substituted alkynyl, nyl, heteroalkyl, substituted heteroalkyl, heteroalkenyl, substituted heteroalkenyl, heteroalkynyl, substituted heteroalkynyl, cycloalkyl, cycloalkenyl, substituted cycloalkyl, substituted cycloalkenyl, halogen, hydroxy, alkoxy, aryloxy, carbonyl, amino, amido, thio and phosphino; B is preferably selected independently of one another from C 1-6 -alkyl, C 1-6 -alkenyl, C 1-6 -alkynyl, C 3-8 -alkylene

Cycloalkyl, C 3-8 -cycloalkenyl, alkoxy, aryloxy, amino and amido.

The expression independently of one another means that when n is 2 or greater, the substituents B may be the same or different radicals from the named groups.

Alkyl in the present application means branched or unbranched, saturated acyclic hydrocarbon radicals. Examples of suitable alkyl radicals are methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, isobutyl, etc. Preferred are alkyl radicals having 1 to 50 carbon atoms, more preferably 1 to 20 carbon atoms, very particularly preferably having 1 to 6 carbon atoms and in particular having 1 to 3 carbon atoms used.

Alkenyl according to the present application is to be understood as meaning branched or unbranched acyclic hydrocarbon radicals which have at least one carbon-carbon double bond. Suitable alkenyl radicals are, for example, 2-propenyl, vinyl, etc. The alkenyl radicals preferably have 2 to 50 carbon atoms, particularly preferably 2 to 20 carbon atoms, very particularly preferably 2 to 6 carbon atoms and in particular 2 to 3 carbon atoms. Furthermore, the term alkenyl is to be understood as meaning those radicals which have either a cis or a trans orientation (alternatively E or Z orientation).

Alkynyl according to the present application is to be understood as meaning branched or unbranched acyclic hydrocarbon radicals which have at least one carbon-carbon triple bond. The alkynyl radicals preferably have 2 to 50 carbon atoms, particularly preferably 2 to 20 carbon atoms, very particularly preferably 1 to 6 carbon atoms and in particular 2 to 3 carbon atoms.

Substituted alkyl, substituted alkenyl and substituted alkynyl are alkyl-alkenyl and alkynyl radicals in which one or more hydrogen atoms bound to one carbon atom of these radicals are replaced by another group. Examples of such other groups are heteroatoms, halogen, aryl, substituted aryl, cycloalkyl, cycloalkenyl, substituted cycloalkyl, substituted cycloalkenyl and combinations thereof. Examples of suitable substituted alkyl radicals are benzyl, trifluoromethyl and the like By the terms heteroalkyl, heteroalkenyl and heteroalkynyl are meant alkyl-alkenyl and alkynyl radicals wherein one or more of the carbon atoms in the carbon chain are replaced by a heteroatom selected from N, O and S. The bond between the heteroatom and another carbon atom may be saturated or optionally unsaturated.

Cycloalkyl according to the present application is to be understood as meaning saturated cyclic nonaromatic hydrocarbon radicals which are composed of a single ring or several condensed rings. Suitable cycloalkyl radicals are, for example, cyclopentyl, cyclohexyl, cyclooctanyl, bicyclooctyl, etc. The cycloalkyl radicals preferably have between 3 and 50 carbon atoms, particularly preferably between 3 and 20 carbon atoms, very particularly preferably between 3 and 8 carbon atoms and in particular between 3 and 6 carbon atoms.

By cycloalkenyl, according to the present application, partially unsaturated, cyclic non-aromatic hydrocarbon radicals are to be understood which have a single or multiple condensed rings. Suitable cycloalkenyl radicals are, for example, cyclopentenyl, cyclohexenyl, cyclooctenyl etc. The cycloalkenyl radicals preferably have 3 to 50 carbon atoms, particularly preferably 3 to 20 carbon atoms, very particularly preferably 3 to 8 carbon atoms and in particular 3 to 6 carbon atoms.

Substituted cycloalkyl and substituted cycloalkenyl radicals are cycloalkyl and cycloalkenyl radicals in which one or more hydrogen atoms of any carbon atom of the carbon ring are replaced by another group. Such other groups are, for example, halogen, alkyl, alkenyl, alkynyl, substituted alkyl, substituted alkenyl, substituted alkynyl, aryl, substituted aryl, cycloalkyl, cycloalkenyl, substituted cycloalkyl, substituted cycloalkenyl, an aliphatic heterocyclic radical, a substituted aliphatic heterocyclic radical, Heteroaryl, substituted heteroaryl, alkoxy, aryloxy, boryl, phosphino, amino, silyl, thio, seleno and combinations thereof. Examples of substituted cycloalkyl and cycloalkenyl radicals are 4-dimethylaminocyclohexyl, 4,5-dibromocyclohept-4-enyl and the like. a.

For the purposes of the present application, aryl is to be understood as meaning aromatic radicals which have a single aromatic ring or a plurality of aromatic rings which are condensed, linked via a covalent bond or can be replaced by a suitable moiety, eg. Example, a methylene or ethylene unit are linked. Such suitable moieties may also be carbonyl moieties, such as in benzophenol, or oxygen moieties, such as in diphenyl ether, or nitrogen moieties, such as in diphenylamine. The aromatic ring or the aromatic rings are, for example, phenyl, naphthyl, diphenyl, diphenyl ether, diphenylamine and benzophenone. Preferably have the aryl radicals have 6 to 50 carbon atoms, more preferably 6 to 20 carbon atoms, most preferably 6 to 8 carbon atoms.

Substituted aryl radicals are aryl radicals wherein one or more hydrogen atoms attached to carbon atoms of the aryl radical are replaced by one or more other groups. Suitable other groups are alkyl, alkenyl, alkynyl, substituted alkyl, substituted alkenyl, substituted alkynyl, cycloalkyl, cycloalkenyl, substituted cycloalkyl, substituted cycloalkenyl, heterocyclo, substituted heterocyclo, halogen, halogen-substituted alkyl (eg CF 3), hydroxy, Amino, phosphino, alkoxy, thio and both saturated and unsaturated cyclic hydrocarbons which may be condensed to the aromatic ring or to the aromatic rings or may be linked by a bond, or may be linked together via a suitable group. Suitable groups have already been mentioned above.

Heterocyclo according to the present application means a saturated, partially unsaturated or unsaturated cyclic radical in which one or more carbon atoms of the radical are represented by a heteroatom, e.g. B. N, O or S are replaced. Examples of heterocyclo radicals are piperazinyl, morpholinyl, tetrahydropyranyl, tetrahydrofuranyl, piperidinyl, pyrolidinyl, oxazolinyl, pyridyl, pyrazyl, pyridazyl, pyrimidyl.

Substituted heterocyclo radicals are those heterocyclo radicals in which one or more hydrogen atoms which are bonded to one of the ring atoms are replaced by another group. Other suitable groups include halogen, alkyl, substituted alkyl, aryl, substituted aryl, heteroaryl, substituted heteroaryl, alkoxy, aryloxy, boryl, phosphino, amino, silyl, thio, seleno, and combinations thereof.

Alkoxy radicals are radicals of the general formula -OZ ¹ , where Z ^{1 is} selected from alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, heterocycloalkyl, substituted heterocycloalkyl, SiIyI and combinations thereof. Suitable alkoxy radicals are, for example, methoxy, ethoxy, benzyloxy, t-butoxy, etc. The term aryloxy means those radicals of the general formula -OZ ¹ , wherein Z ^{1 is} selected from aryl, substituted aryl, heteroaryl, substituted heteroaryl and combinations from that. Suitable aryloxy radicals are phenoxy, substituted phenoxy, 2-pyridinoxy, 8-quinolinoxy and others

Amino radicals are radicals of the general formula -NZ ¹ Z ² , where Z ¹ and Z ^{2 are} independently selected from hydrogen, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, heterocycloalkyl, substituted heterocycloalkyl, aryl, substituted Aryl, heteroaryl, substituted heteroaryl, alkoxy, aryloxy, SiIyI and combinations thereof. Aromatic or heteroaromatic hydrocarbons preferably used in the amination process according to the invention are selected from benzene, diphenylmethane, naphthalene, anthracene, toluene, xylene, phenol and aniline and also pyridine, pyrazine, pyridazine, pyrimidine and quinoline. It is also possible to use mixtures of the said aromatic or heteroaromatic hydrocarbons. Particular preference is given to using the aromatic hydrocarbons, benzene, naphthalene, anthracene, toluene, xylene, pyridine, phenol and / or aniline, very particularly preferably benzene, toluene and / or pyridine.

Benzene is particularly preferably used in the amination process according to the invention, so that aniline is formed as the product.

As the compound by which the amino group is introduced, ammonia is particularly preferably used. This means that according to the invention the hydrocarbons, in particular the benzene, are more preferably reacted with ammonia. Optionally, compounds can also be used which split off ammonia under the reaction conditions.

For the preparation of mono and di-alkyl-N, (N) -substituted aromatic amines, for example of mono- and / or dimethylaniline, it is also possible to use mono- and di-alkylamines, preferably mono- and di (m) ethylamine, be used.

The reaction conditions in the amination process according to the invention depend inter alia on the aromatic hydrocarbon to be aminated and the catalyst used.

The amination, preferably the amination of benzene, ie the reaction of benzene with ammonia, is generally carried out at temperatures of 200 to 800 ⁰ C, preferably 300 to 500 ⁰ C, more preferably 350 to 400 ⁰ C and most preferably 350 to 500 ⁰ C.

The reaction pressure is in the amination, preferably in the amination of benzene, d. H. the reaction of benzene with ammonia, preferably 1 to 1000 bar, more preferably 2 to 300 bar, in particular 2 to 150 bar, particularly preferably 15 to 1 10 bar.

The residence time in the amination process according to the invention, preferably in the amination of benzene, when carried out in a batch process is generally from 15 minutes to 8 hours, preferably from 15 minutes to 4 hours, more preferably from 15 minutes to 1 hour. When carried out in a preferred continuous process, the residence time is generally 0.1 second to 20 minutes, preferably 0.5 second to 10 minutes. For the preferred continuous Process means "residence time" in this context, the residence time on the catalyst for fixed bed catalyst thus the residence time in the catalyst bed, for fluidized bed reactors, the synthesis part of the reactor is considered (part of the reactor where the catalyst is located).

The relative amount of the hydrocarbon used and the amine component depends on the amination reaction carried out and the reaction conditions. Generally, at least stoichiometric amounts of the hydrocarbon and amine component are employed. Usually, however, it is preferred to use one of the reactants in stoichiometric excess to achieve equilibrium shift to the desired product side and thus higher conversion. Preferably, the amine component is used in stoichiometric excess.

The amination process according to the invention can be carried out continuously, batchwise or semi-continuously. Suitable reactors are thus both stirred tank reactors and tubular reactors. Typical reactors are, for example, high-pressure stirred tank reactors, autoclaves, fixed bed reactors, fluidized bed reactors, moving beds, circulating fluidized beds, salt bath reactors, plate heat exchangers as reactors, tray reactors with multiple trays with / without heat exchange or withdrawal / supply of partial streams between the trays possible embodiments as radial flow or axial flow reactors, continuously stirred boilers, bubble reactors, etc., wherein in each case for the desired reaction conditions (such as temperature, pressure and residence time) suitable reactor is used. The reactors can each be used as a single reactor, as a series of individual reactors and / or in the form of two or more parallel reactors. The reactors can be operated in an AB driving style (alternating driving style). The process according to the invention can be carried out as a batch reaction, semi-continuous reaction or continuous reaction. The specific reactor design and the performance of the reaction may vary depending on the amination procedure to be performed, the state of matter of the aromatic hydrocarbon to be aminated, the reaction times required, and the nature of the catalyst employed. The process according to the invention for directamination is preferably carried out in a high-pressure stirred tank reactor, fixed bed reactor or fluidized bed reactor.

In a particularly preferred embodiment, one or more fixed bed reactors is used in the amination of benzene to aniline.

The hydrocarbon and the amine component can be added in gaseous or liquid form to the reaction zone of the respective reactor. The preferred phase depends in each case on the amination carried out and the th reactor. In a preferred embodiment, for example in the preparation of aniline from benzene, benzene and ammonia are preferably present as gaseous reactants in the reaction zone. Typically, benzene is thereby added as a liquid which is heated and vaporized to form a gas, while ammonia is present either in gaseous form or in the supercritical phase in the reaction zone. It is also possible that benzene is in supercritical phase at least together with ammonia.

The hydrocarbon and the amine moiety may be added together to the reaction zone of the reactor, for example as a premixed reactant stream, or separately. In a separate addition, the hydrocarbon and amine component may be added to the reaction zone of the reactor either simultaneously, with a time lag or sequentially. Preferably, the addition of the amine component and the addition of the hydrocarbon take place with a time lag.

If appropriate, further co-reactants, cocatalysts or further reagents are added to the reaction zone of the reactor in the process according to the invention, in each case depending on the amination carried out. For example, in the amination of benzene, oxygen or an oxygen-containing gas may be added to the reaction zone of the reactor, as a co-reactant. The relative amount of gaseous oxygen that can be added to the reaction zone is variable and depends, inter alia, on the catalyst system used. The molar ratio of gaseous oxygen to aniline may be, for example, in the range of 0.05: 1 to 1: 1, preferably 0.1: 1 to 0.5: 1. However, it is also possible to carry out the amination of benzene without the addition of oxygen or an oxygen-containing gas in the reaction zone.

The amination may preferably be carried out at a molar ratio of ammonia to hydrocarbon of at least 1.

Following the amination, the isolation of the desired product can be carried out by methods known to those skilled in the art.

Examples

Example 1: Preparation of catalyst

The preparation of the catalyst is carried out according to DE-A 44 28 004. An aqueous solution of nickel nitrate, copper nitrate and zirconium acetate, the 4.48 wt .-% Ni (calculated as NiO), 1, 52 wt .-% Cu (calculated as CuO and 2.82 wt% Zr (calculated as ZrO2) is simultaneously stirred in a stirred vessel in a constant stream with a 20% aqueous sodium carbonate solution at a temperature of 70 ⁰ C precipitated so that the measured with a glass electrode pH of 7.0 is maintained. The suspension obtained is filtered and the filter cake is washed with demineralized water until the electrical conductivity of the filtrate is about 20 μS. Then so much ammonium heptamolybdate is incorporated into the still wet filter cake that the oxide mixture indicated below is obtained. Thereafter, the filter cake is dried at a temperature of 150 ⁰ C in a drying oven or a spray dryer. The obtained in this way hydroxide-carbonate mixture is then annealed at a temperature of 430 to 460 ⁰ C over a period of 4 hours. The oxidic species prepared in this way has the composition: 50% by weight of NiO, 17% by weight of CuO, 1.5% by weight of MoO ₃ and 31.5% by weight of ZrO ₂ . The catalyst was mixed with 3% by weight of graphite and formed into tablets.

Example 2: Preparation of catalyst

An aqueous solution of nickel nitrate, copper nitrate, magnesium nitrate and aluminum nitrate containing 11.1 Kg total solution 8.1 Kg NiO, 2.9 Kg CuO, 2.8 Kg MgO and 10.2 Kg Al2O3 is simultaneously in a stirred vessel in a constant stream with an aqueous solution of 7.75 Kg of sodium carbonate and 78 Kg of sodium hydroxide in 244 liters total volume at a temperature of 20 ⁰ C so precipitated that the measured with a glass electrode pH of 9.5 is maintained. The suspension obtained is filtered and the filter cake is washed with demineralized water until the electrical conductivity of the filtrate is about 20 μS. Thereafter, the filter cake is dried at a temperature of 150 ⁰ C in a drying oven. The resulting hydroxide-carbonate mixture is then tempered at a temperature of 430 to 460 ⁰ C over a period of 4 hours. The oxidic species thus prepared has the composition: 56.6% by weight NiO, 19.6% by weight CuO, 15.4% by weight MgO and 8.5% by weight Al ₂ O ₃ .

Example 3 Preparation of Catalyst (Based on Ni-Co-Cu / ZrO 2 According to EP-A-963 975)

An aqueous solution of nickel nitrate, cobalt nitrate, copper nitrate and zirconium acetate containing 2.29 wt% NiO, 2.39 wt% CoO, 0.94 wt% CuO and 2.82 wt% ZrO ₂ , was simultaneously precipitated in a stirrer vessel in a constant stream with a 20% aqueous sodium carbonate solution at a temperature of 70 ⁰ C so that the measured with a glass electrode pH of 7.0 was maintained. The suspension obtained was filtered and the filter cake was washed with demineralized water until the electrical conductivity of the filtrate was about 20 μS. Thereafter, the filter cake was dried at a temperature of 150 ⁰ C in a drying oven or a spray dryer. The hydroxide-carbonate mixture obtained in this way was then tempered at a temperature of 450 to 500 ⁰ C over a period of 4 hours. The catalyst thus prepared had the composition Composition: 28 wt .-% NiO, 28 wt .-% CoO, 11 wt .-% CuO and 33 wt .-% ZrO ₂ . The catalyst was mixed with 3% by weight of graphite and formed into tablets. The oxidic tablets were reduced. The reduction was carried out at 280 ⁰ C, with a heating rate of 3 ° C / minute. First, it was reduced for 50 minutes with 10% H ₂ in N ₂ , then 20 minutes with 25% H ₂ in N ₂ , then 10 minutes with 50% H ₂ in N ₂ , then 10 minutes with 75% H ₂ in N ₂ and finally 3 hours with 100% H ₂ . The percentages are% by volume. The passivation of the reduced catalyst was carried out at room temperature in dilute air (air in N ₂ with an O ₂ content of not more than 5% by volume).

Example 4 Amination of Benzene on Catalyst without Addition of Nitrobenzene (Comparative Example)

A tube reactor, filled with 2-4 mm quartz glass chippings at the reactor inlet, 20 ml = 23.6 g of catalyst from Example 1 in the form of 6x3 mm tablets and 2-4 mm quartz glass chippings at the reactor outlet under air (50 Nl / h) to 350 ⁰ C heated up. After heating, the air supply is stopped, the reactor is purged with nitrogen, then the feed is started. At a total pressure of 85 bar and an internal reactor temperature of 350 ⁰ C, 59.4 g of benzene / hour and 1 18 g ammonia / hour are fed to the catalyst. The discharge from the reactor is cooled to a temperature of 2 ⁰ C, the condensate homogenized with methanol and analyzed by gas chromatography with internal standard. The aniline yield in a bulk sample, for which the collection period was started after 3.5 h running time and ended after 4 h, 8.2 mmol aniline / mol of added benzene and hour. This corresponds to a space-time yield of 28.89 g of aniline / liter of catalyst per hour.

An on-line gas chromatography sample of the exhaust gas, which consists mainly of ammonia, gave after a test run time of 4.0 h, a hydrogen content of 0.128% by volume in the exhaust gas, which corresponds to a hydrogen evolution of 11 mmol hydrogen / mol of benzene and hour.

The amount of hydrogen in the exhaust gas increases continuously with the runtime and with increasing reduction of the catalyst: it is after 1, 4 h 3 mmol H2 / mol benzene and benzene hour, after 2.8 h 8 mmol H2 / mol zugeensem benzene and hour , after 4 h 11 mmol H2 / mol of benzene added and hour and after 4.6 h 14 mmol H2 / mol of benzene fed in and hour.

Example 5 (Inventive): Amination of benzene on catalyst with the addition of 0.5% nitrobenzene in the benzene feed

A tube reactor filled with 2-4 mm quartz glass chippings at the reactor inlet, 20 ml = 23.6 g of catalyst from Example 1 in the form of 6 × 3 mm tablets and 2-4 mm quartz glass split at the reactor outlet, is heated to 350 ⁰ C under air (50 Nl / h). After heating, the air supply is stopped, the reactor is purged with nitrogen, then the feed is started. At a total pressure of 85 bar and an internal reactor temperature of 350 ⁰ C, the catalyst per hour 59.6 g of an aromatic mixture consisting of 99.5% benzene and 0.5% nitrobenzene (ie 0.3 g nitrobenzene / h or 0.002 mol of nitrobenzene Ih) and 118 g of ammonia / hour. The discharge from the reactor is cooled to a temperature of 2 ⁰ C, the condensate homogenized with methanol and analyzed by gas chromatography with internal standard. The aniline yield is in a bulk sample, for which the collection period was started after 3.5 h running time and ended after 4 h, 1 1, 3 mmol aniline / mol aromatics fed and hour. This corresponds to a space-time yield of 40.15 g aniline / liter of catalyst and hour.

An on-line gas chromatography sample of the exhaust gas, which consists mainly of ammonia, gave after a test run time of 4.0 h, a hydrogen content of 0.034 vol% in the exhaust gas, which corresponds to a hydrogen evolution of 4 mmol hydrogen / mol of benzene and hour.

The amount of hydrogen in the exhaust gas increases again in this example with the time and with increasing reduction of the catalyst, but at a much lower absolute level and slower than in Example 3: It is after 1, 2 h 1 mmol H2 / mol of aromatics fed in and Hour, after 2,1 h 2 mmol H 2 / mol of aromatics fed in and hour, after 4 h 4 mmol H 2 / mol of aromatics fed in and hour and after 4.8 h 5 mmol of H 2 / mol of added aromatics and hour.

Example 6 (Inventive): Amination of benzene on catalyst with the addition of 1, 0% nitrobenzene in the benzene feed

A tube reactor, filled with 2-4 mm quartz glass chippings at the reactor inlet, 20 ml = 23.6 g of catalyst from Example 1 in the form of 6x3 mm tablets and 2-4 mm quartz glass chippings at the reactor outlet, under air (50 Nl / h) on 350 ⁰ C heated. After heating, the air supply is stopped, the reactor is purged with nitrogen, then the feed is started. At a total pressure of 85 bar and an internal reactor temperature of 350 ⁰ C, the catalyst per hour 59.1 g of an aromatic mixture consisting of 99.0% benzene and 1, 0% nitrobenzene (ie 0.6 g nitrobenzene / h or 0.005 mol nitrobenzene Ih) and 118 g ammonia / hour. The discharge from the reactor is cooled to a temperature of 2 ⁰ C, the condensate homogenized with methanol and analyzed by gas chromatography with internal standard. The aniline yield is 17.8 mmol aniline / mole aromatics added and hour in a bulk sample for which the collection period was started after 3.5 h runtime and ended after 4 h. This corresponds to a space-time yield of 62.93 g aniline / liter of catalyst and hour. An on-line gas chromatography sample of the exhaust gas, which consists mainly of ammonia, gave after a test run time of 4.0 h, a hydrogen content of 0.025 vol% in the exhaust gas, which corresponds to a hydrogen evolution of 2 mmol hydrogen / mol of benzene and hour.

The amount of hydrogen in the exhaust gas increases again in this example with the duration and with increasing reduction of the catalyst, but at an even lower absolute level and slower than in Example 4: It is after 1, 0 h 1 mmol H2 / mol aromatics fed and Hour, after 2.1 h 1 mmol H 2 / mol of aromatics fed in and hour, after 3.0 h 2 mmol H 2 / mol of aromatics fed in and hour, after 4 h 2 mmol H 2 / mol of added aromatics and hour and after 5.0 h 3 mmol H2 / mol aromatics fed and hour.

Example 7 (Inventive): Amination of benzene on catalyst with the addition of 3.0% nitrobenzene in the benzene feed

A tube reactor, filled with 2-4 mm quartz glass chippings at the reactor inlet, 20 ml = 23.6 g of catalyst from Example 1 in the form of 6x3 mm tablets and 2-4 mm quartz glass split at the reactor outlet, under air (50 Nl / h ) heated to 350 ⁰ C. After heating, the air supply is stopped, the reactor is purged with nitrogen, then the feed is started. At a total pressure of 85 bar and an internal reactor temperature of 350 ⁰ C, the catalyst per hour 60.1 g of an aromatic mixture consisting of 97% benzene and 3% nitrobenzene (ie, 1.858 g nitrobenzene / h or 0.015 mol nitrobenzene / h), as well as 118 g ammonia / hour supplied. The discharge from the reactor is cooled to a temperature of 2 ⁰ C, the condensate homogenized with methanol and analyzed by gas chromatography with internal standard. The aniline yield is 12.2 mmol aniline / mole of aromatics added per hour in a bulk sample for which the collection period was started after 3.5 h running time and ended after 4 h. This corresponds to a space-time yield of 44.39 g aniline / liter of catalyst and hour. The peak value was reached in this experiment already after 1 h and was 15.1 mmol aniline / mol aromatics fed and hour. This corresponds to a space-time yield of 55.24 g aniline / liter of catalyst and hour.

All of the gas chromatography online samples from this experiment, which consists primarily of ammonia, gave a hydrogen content below the detection limit of the GC instrument, ie approximately <30-50 ppm. Even after 5 h run time no hydrogen could be detected.

Example 8 (Inventive): Amination of benzene on catalyst with the addition of 1 1, 1% nitrobenzene in the benzene feed A tube reactor, filled with 2-4 mm quartz glass chippings at the reactor inlet, 20 ml = 23.6 g of catalyst from Example 1 in the form of 6x3 mm tablets and 2-4 mm quartz glass chippings at the reactor outlet, under air (50 Nl / h) on 350 ⁰ C heated. After heating, the air supply is stopped, the reactor is purged with nitrogen, then the feed is started. At a total pressure of 85 bar and an internal reactor temperature of 350 ⁰ C, the catalyst per hour, 61, 3 g of an aromatic mixture consisting of 88.9% benzene and 1 1, 1% nitrobenzene (ie, 6.8 g nitrobenzene / h or 0.055 mol nitrobenzene / h) and 118 g ammonia / hour. The training contract from the reactor is cooled to a temperature of 2 ⁰ C, homogenized the condensate with methanol and analyzed by gas chromatography using an internal standard. The aniline yield is 30.9 mmol aniline / mol of aromatics fed in and hour in a bulk sample for which the collection period was started after 3.5 h running time and ended after 4 h. This corresponds to a space-time yield of 120.78 g aniline / liter of catalyst and hour. The peak value was reached in this experiment already after 1 h and was 43.8 mmol aniline / mol aromatics fed and hour. This corresponds to a space-time yield of 171, 36 g aniline / liter of catalyst and hour.

Claims

claims

1. A process for the amination of hydrocarbons with ammonia, characterized in that one carries out the amination in the presence of an additive which reacts with hydrogen, being used as an additive at least one organic chemical compound, N2O, hydroxylamine, hydrazine and / or carbon monoxide.

2. The method according to claim 1, characterized in that as an additive which reacts with hydrogen, carbon monoxide, carbonyl compounds, nitriles, imines, amides, nitro compounds, nitroso compounds, olefins, alkynes, organic peroxides, organic acids, organic acid derivatives, hydrazine derivatives , Hydroxylamines, quinones, aromatics and / or molecules with sp 2 -hybridized carbon atoms.

3. The method according to claim 1, characterized in that as an additive which reacts with hydrogen, nitrobenzene, carbon monoxide, hydrocyanic acid, acetonitrile, propionitrile, butyronitrile, benzonitrile, imines from the reaction of benzaldehyde with ammonia or primary amines, imines from the reaction aliphatic aldehydes with ammonia or primary amines, formamide, acetamide, benzamide, nitrosobenzene, ethene, propene, 1-butene, 2-butene, isobutene, n-pentene and pentene isomers, cyclopentene, n-hexene, hexene isomers, Cyclohexene, n-heptene, heptene isomers, cycloheptene, n-octene, octadiene, cyclooctene, cyclooctadiene, acetylene, propyne, butyne, phenylacetylene, meta-chloroperbenzoic acid, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, oxalic acid,

Malonic acid, succinic acid, maleic acid, fumaric acid, esters or anhydrides of said carboxylic acids, hydrazine, phenylhydrazine, hydrazides of aliphatic or aromatic ketones, hydroxylamine, alkylhydroxylamines and / or arylhydroxylamine.

4. The method according to claim 1, characterized in that one uses as an additive which reacts with hydrogen, reducible nitrogen-containing compounds, acetylene, alkynes having 3 to 6 carbon atoms and / or olefins having 2 to 6 carbon atoms.

5. The method according to claim 1, characterized in that is used as an additive which reacts with hydrogen, nitrobenzene.

6. The method according to claim 1, characterized in that is used as an additive which reacts with hydrogen, hydrazine.

7. The method according to claim 1, characterized in that is used as an additive which reacts with hydrogen, hydroxylamine.

8. The method according to claim 1, characterized in that is used as an additive which reacts with hydrogen, N2O

9. The method according to claim 1, characterized in that reacting benzene with ammonia in the presence of catalyst which catalyzes the amination, and as an additive which reacts with hydrogen, nitrobenzene.

10. The method according to claim 1, characterized in that one doses the additive which reacts with hydrogen, together with the hydrocarbon at the entrance of the reactor.

1 1. A method according to claim 1, characterized in that one introduces a nitrobenzene / benzene mixture in a common feed line and ammonia in another feed line, in each case at the entrance of the reactor in the reactor.

12. The method according to claim 1, characterized in that one first combines a nitrobenzene / benzene mixture from a common feed line and the ammonia from a second feed line in a mixer or evaporator and as a homogeneous mixture on a catalyst bed, which is the amination catalyzed.

13. The method according to claim 1, characterized in that the weight fraction of the additive which reacts with hydrogen, between 0.001 wt .-% and 50 wt .-%, based on the total weight of the hydrocarbon used and the additive.

14. The method according to claim 1, characterized in that one uses a mixture containing benzene and nitrobenzene, which contains between 0.1 wt.% And 15 wt.% Nitrobenzene, based on the total weight of nitrobenzene and benzene.

15. The method according to claim 1, characterized in that one uses catalyst which catalyzes both the direct amination of the hydrocarbon and the hydrogenation of the additive.

16. The method according to claim 1, characterized in that is used as catalyst gate compounds containing Ni-Cu-X, Fe-Cu-X, Ni-Cu-Co-X and / or Co-Cu-X, wherein X represents Ag or Mo.

17. The method according to claim 16, characterized in that in the catalyst, the proportion by weight of the elements Ni, Co and Fe together between 0.1 wt .-% and 75 wt .-% and the weight fraction of Cu between 0.1 wt. % and 75 wt .-%, each based on the total weight of the catalyst.

18. The method according to claim 16, characterized in that the weight fraction of the doping element X to the total weight of the catalyst is between 0.01 wt .-% and 8 wt .-%, based on the total weight of the catalyst.

19. The method according to claim 1, characterized in that one uses as catalyst NiO, CuO and / or Moθ3 on zirconium oxide as a carrier.

20. The method according to claim 1, characterized in that one uses as the catalyst NiO, CuO and / or CoO on zirconium oxide as a carrier.

21. The method according to claim 1, characterized in that one uses as a catalyst NiO, CuO and / or Fe2Ü3 on zirconium oxide as a carrier.

22. The method according to claim 1, characterized in that one uses as catalyst NiO, CuO and / or Fe2Ü3 on magnesium-aluminum oxide as a carrier.

23. The method according to claim 1, characterized in that at least one of the following compound (a), (b), (c) and / or (d):

(a) containing, preferably consisting of NiO, CuO and MOO3, on zirconium oxide as support,

(b) (preferably, mainly) containing NiO, CuO and CoO on zirconia as

Carrier,

(c) containing, preferably consisting of NiO and / or CuO and / or Fe 2 O 3 on zirconium oxide as support,

(d) containing, preferably consisting of NiO and / or CuO and / or Fe 2 O 3 on magnesium-aluminum oxide as support,

wherein the catalysts (a) to (d) can be used individually or in combination with one another.

24. The method according to claim 1, characterized in that one carries out the amination continuously.

25. The method according to claim 1, characterized in that one carries out the amination at temperatures between 200 and 800 ⁰ C.

26. The method according to claim 1, characterized in that one carries out the amination at pressures between 1 to 1000 bar.