WO2011003934A2

WO2011003934A2 - Method for the direct amination of hydrocarbons into amino hydrocarbons, including electrochemical separation of hydrogen

Info

Publication number: WO2011003934A2
Application number: PCT/EP2010/059711
Authority: WO
Inventors: Petr Kubanek; Alexander Panchenko; Andreas Fischer; Thomas Heidemann
Original assignee: Basf Se
Priority date: 2009-07-10
Filing date: 2010-07-07
Publication date: 2011-01-13
Also published as: WO2011003934A3

Abstract

Disclosed is a method for the direct amination of hydrocarbons into amino hydrocarbons by reacting a feedstock stream E containing at least one hydrocarbon and at least one amination reagent so as to obtain a reaction mixture R containing amino hydrocarbon and hydrogen in a reaction zone RZ, and electrochemically separating at least some of the hydrogen produced during the reaction from the reaction mixture R by means of a gas-tight membrane-electrode assembly comprising at least one membrane selectively conducting protons and at least one electrode catalyst on each side of the membrane, wherein at least some of the hydrogen is oxidized to protons on the anode catalyst on the retentate side of the membrane, and after penetrating the membrane, some of the protons on the permeate side are b1) reduced to hydrogen on the cathode catalyst by applying a voltage, and some of the protons b2) are reacted with oxygen on the cathode catalyst to obtain water, thereby generating electricity, the oxygen being fed from an oxygen-containing stream O that is brought in contact with the permeate side of the membrane.

Description

Process for the direct amination of hydrocarbons to aminohydrocarbons with electrochemical separation of hydrogen

description

The present invention relates to a process for the direct amination of hydrocarbons with an aminating reagent to aminocarbons in the presence of a catalyst, wherein at least a portion of the resulting hydrogen in the reaction is separated by electrochemical means of a gas-tight membrane electrode assembly. In this case, at least a portion of the hydrogen is oxidized to protons on the retentate side of the membrane. The protons, after passing through the membrane on the permeate side, are reduced in part by applying a voltage to hydrogen and, on the other hand, are reacted with oxygen to produce electric current. The oxygen originates from an oxygen-containing stream O, which is brought into contact with the permeate side of the membrane.

The commercial production of amino hydrocarbons from hydrocarbons is usually carried out in multi-stage reactions. Thus, in the production of aniline from benzene, a benzene derivative such as nitrobenzene, chlorobenzene or phenol is first prepared, which is then reacted in one or more stages reactions to aniline.

There are also known processes for the direct production of aminocarbons from the corresponding hydrocarbons. Reactions in which aminocarbons are produced directly from the corresponding hydrocarbons are referred to as direct amination. Wibaut first describes the heterogeneously catalyzed direct amination of benzene in 1917 (Berichte 1917, 50, 541-546).

In Direktamination the reaction of the hydrocarbon used to the corresponding amino hydrocarbon takes place with the release of hydrogen. In the direct amination of benzene to aniline, 1 mol of aniline and 1 mol of hydrogen are formed from 1 mol of benzene and 1 mol of ammonia. The direct amination of benzene to aniline is limited by the location of the thermodynamic equilibrium. The equilibrium conversion is at temperatures of 350 ⁰ C at about 0.5 mol% based on benzene.

Due to the low equilibrium conversion, a shift in the position of the thermodynamic equilibrium on the side of the amino hydrocarbons is necessary for the economic implementation of Direktaminierung. One possibility is to separate off part of the hydrogen from the reaction mixture of the direct amination, which contains amino hydrocarbon, unreacted starting materials and hydrogen, and to reuse the unreacted starting materials in the direct amination reaction. The separation of the hydrogen from the reaction mixture is necessary, since otherwise the thermodynamic equilibrium is shifted in the direction of the educts by the hydrogen, whereby the yield of aminocarbon is even lower in the renewed direct lamination. Another possibility is to remove the hydrogen formed in the direct amination directly from the reaction zone. Several methods are described for removing the hydrogen from the reaction mixture.

WO 2007/096297 and WO 2000/69804 describe a process for the direct amination of aromatic hydrocarbons to give the corresponding aminocarbons, the resulting hydrogen being removed from the reaction mixture by oxidation on reducible metal oxides. These processes have the disadvantage that the reducible metal oxides have to be regenerated with oxygen again after some time. This means costly interruptions of the process, since the direct amination of the hydrocarbons and the regeneration of the reducible metal oxides usually do not take place under the same conditions. For regeneration of the catalyst, the reactor must therefore usually be relaxed, rinsed and rendered inert.

Another undesirable side reaction that occurs in the direct amination of hydrocarbons to aminocarbons is the decomposition of ammonia to hydrogen. This decomposition is disadvantageous because, on the one hand, the educt ammonia is lost and, on the other hand, the hydrogen formed during the decomposition leads to a further unfavorable shift in the equilibrium position in the direction of the products. In the catalysts described in WO 2007/096297 and WO 2000/69804, the undesired decomposition of ammonia increases with increasing degree of reduction of the metal oxides, so that with increasing degree of reduction the equilibrium position is shifted further and further in the direction of the educts.

WO 2007/099028 describes a direct amination of aromatic hydrocarbons to the corresponding amino hydrocarbons, wherein in a first step, the heterogeneously catalyzed Direktaminierung is carried out and in a second step, the hydrogen formed in the first step by the reaction with an oxidizing agent such as air, oxygen, CO, CO ₂ , NO and / or N ₂ O is reacted. The use of oxidants such as oxygen leads to the oxidation of ammonia and the formation of further by-products. This leads to higher material costs and additional work-up steps, whereby the economic efficiency of the process is worsened. WO 2008/009668 also describes a process for the direct amination of aromatic hydrocarbons. The removal of hydrogen from the reaction mixture is achieved here by carrying out the direct amination with the addition of compounds which react with the hydrogen formed in the direct amination. Examples of compounds added to the direct amination are nitrobenzene and carbon monoxide. Also in this method, the disadvantages described above occur. WO 2007/025882 describes the direct amination of aromatic hydrocarbons to the corresponding amino hydrocarbons, wherein hydrogen is physically separated from the reaction mixture. The separation takes place here by a selectively hydrogen-permeable membrane, that is, hydrogen migrates as H ₂ molecule through the membrane. Palladium and palladium alloys are preferably used as membrane materials. The diffusion rate in this process depends on the partial pressure difference of the hydrogen between the retentate and permeate sides of the membrane. In order to achieve higher diffusion rates, it is necessary to work at higher pressure differences, which place high demands on the mechanical stability of the membrane. In Basile, top. Catal. (2008), 51, 107- 122, is described in addition to temperatures above 300 ⁰ C are required to achieve a sufficiently high diffusion rate. In addition, appropriate devices for compressing and expanding the gas mixture must be present to form the pressure differences. For thermodynamic reasons, a certain amount of hydrogen always remains in the retentate. This has a negative effect on the position of the thermodynamic equilibrium.

The object of the present invention is therefore to provide a process for the direct amination of hydrocarbons to aminohydrocarbons, wherein the hydrogen is separated from the reaction mixture as effectively as possible, and that avoids the above-mentioned disadvantages of the prior art processes for Direktaminierung. In addition, the method should allow a shift in the position of the thermodynamic equilibrium on the side of Aminokohlenwas- substances. In particular, the separation of the hydrogen should be made possible directly from the reaction zone. The hydrocarbons used should be used efficiently as well as the by-products obtained during the reaction. The method should have the best possible energy balance and the lowest possible expenditure on equipment.

The object is achieved according to the invention by a process for the direct amination of hydrocarbons to aminohydrocarbons by reacting an ethylene stream E which comprises at least one hydrocarbon and at least one amine to a reaction mixture R containing Aminokohlen- hydrogen and hydrogen in a reaction zone RZ, and electrochemical separation of at least a portion of the resulting in the reaction of hydrogen from the reaction mixture R by means of a gas-tight membrane electrode assembly, the at least one selectively proton-conducting membrane and on each side of the membrane has at least one electrode catalyst, wherein on the retentate side of the membrane at least a portion of the hydrogen is oxidized at the anode catalyst to protons and the protons after passing through the membrane on the permeate side of the cathode catalyst partially according to

b1) are reduced by applying a voltage to hydrogen and partially according to

b2) are reacted with water to produce electric current, wherein the oxygen comes from an oxygen-containing stream O, which is brought into contact with the permeate side of the membrane.

In contrast to the known processes in which the hydrogen is removed by reducible metal oxides, the process according to the invention has the advantage that complicated and cost-intensive interruptions of the process for directamination can be avoided and that the process can be operated continuously over a relatively long period of time , The inventive method also comes in comparison to known methods in which gaseous oxidizing agents such as air, oxygen, CO, CO ₂ , NO or N ₂ O or compounds such as nitrobenzene are used without a complex apparatus and costly separation of the resulting by the addition of the oxidants by-products out.

A particular advantage of the process according to the invention is the electrochemical separation of the hydrogen formed from the reaction mixture R. The driving force of the electrochemical hydrogen separation according to sub-stage b1) is the potential difference between the two sides of the membrane. Since the separation is not dependent on the partial pressure difference of the hydrogen between the two sides of the membrane, as in the commonly used hydrogen-selective membranes, the hydrogen separation can be carried out at much lower pressures and pressure differentials, preferably to an externally impressed pressure difference is dispensed with and prevails in particular on Permeat- and Retentatseite the same pressure. This significantly reduces the mechanical stress on the membrane, which, inter alia, increases its long-term stability and increases the choice of materials that are suitable for the membrane. This also provides the opportunity to carry out the separation of the hydrogen at low pressures than conventional membranes. The electrochemical separation of the hydrogen is significantly more effective compared to the separation by means of conventional hydrogen-selective membranes, therefore, with the same separation performance, the required membrane area can be reduced or significantly more hydrogen can be separated while maintaining the same membrane area. Overall, the method according to the invention is therefore associated with less expenditure on equipment.

Sub-stage b2) has the particular advantage of combining the electrochemical separation of the hydrogen formed from the reaction mixture R with the simultaneous production of electrical current.

The hydrogen is not, as known from the prior art, first separated and then supplied as hydrogen to a power generating process such as an external fuel cell or gas turbine, but the power generation takes place already during the separation. Compared to the known from the prior art method, depending on the angle, a separator or a unit for energy production from the resulting hydrogen and the associated energy and substance losses saved. The combination of substeps b1) and b2) is very particularly advantageous in the process according to the invention since the stream generated in substep b2) can be used directly for the reduction of the protons in substep b1). How much hydrogen is separated after each of substeps b1) and b2) can be set as desired, depending on whether more hydrogen or electricity is to be generated.

The process according to the invention thus provides economical utilization of the starting materials used, with simultaneous flexible production of valuable aminocarbons, hydrogen and electrical energy. In addition, the process according to the invention has the advantage that the hydrogen formed in the directamination and in the unavoidable decomposition of ammonia is partly recovered by the separation from the reaction mixture. The hydrogen obtained in the process according to the invention has a high purity and can be collected and sold or used for energy production. Due to the high purity of the hydrogen can be used as starting material in subsequent reactions, especially in those that react sensitively to impurities.

In the following the invention will be described in detail. hydrocarbons:

According to the invention, the feedstock stream E contains at least one hydrocarbon. Suitable hydrocarbons which can be used in the process according to the invention are, for example, hydrocarbons, such as aromatic hydrocarbons, aliphatic hydrocarbons and cycloaliphatic hydrocarbons, which can be arbitrarily substituted and heteroatoms and double or triple bonds within their chain or their ring (s) can have. Aromatic hydrocarbons and heteroaromatic hydrocarbons are preferably used in the amination process according to the invention.

Suitable aromatic hydrocarbons are, for example, unsaturated cyclic hydrocarbons which have one or more rings and contain only aromatic C-H bonds. Preferred aromatic hydrocarbons have one or more 5- and / 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 a carbon and / or heteroatom of the aromatic ring is / are replaced by another radical. Suitable radicals are, for example, substituted or unsubstituted alkyl, alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl, cycloalkyl and / or cycloalkynyl radicals; Halogen, hydroxy, alkoxy, aryloxy, amino, amido, thio and phosphino. Preferred radicals of the aromatic or heteroaromatic hydrocarbons substances are selected from Ci _-6 alkyl, Ci _-6 alkenyl, Ci _-6 alkynyl, C _3-8 cycloalkyl, C _3-8 - cycloalkenyl, alkoxy, aryloxy, amino and amido, wherein the term Ci_6 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 C _3-8 on 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 in turn 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 which is attached directly to a carbon atom or a heteroatom of the aromatic or heteroaromatic ring is attached. Thus, a 6-membered ring preferably has 5 or fewer substituents (groups) and a 5-membered ring preferably has 4 or fewer substituents (groups). 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 substituents (radicals), more preferably 2 or fewer substituents (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 , in which the symbols have the following meaning:

A is independently aryl or heteroaryl, A is preferably selected from among phenyl, diphenyl, benzyl, dibenzyl, naphthyl, anthracene, pyridyl and quinoline; 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 or heteroatoms of A having 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, 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; preferably B is independently selected from C-ι- ₆ alkyl, d- ₆ -alkenyl, C-ι- ₆ alkynyl, C _3-8 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. Preference is given to using alkyl radicals having 1 to 20 carbon atoms, particularly preferably having 1 to 6 carbon atoms and in particular having 1 to 4 carbon atoms. Examples of suitable alkyl radicals are methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl and i-butyl.

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. The alkenyl radicals preferably have 2 to 20 carbon atoms, particularly preferably 2 to 6 carbon atoms and in particular 2 to 3 carbon atoms. Suitable alkenyl radicals are, for example, vinyl and 2-propenyl.

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 20 carbon atoms, particularly preferably 1 to 6 carbon atoms and in particular 2 to 3 carbon atoms. Examples of suitable alkynyl radicals are ethynyl and 2-propynyl.

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 halogen, aryl, substituted aryl, cycloalkyl, cycloalkenyl, substituted cycloalkyl, substituted cycloalkenyl and combinations thereof. Examples of suitable substituted alkyl radicals are benzyl and trifluoromethyl.

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 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. Preferably, the cycloalkyl radicals have between 3 and 8 carbon atoms and more preferably between 3 and 6 carbon atoms. Suitable cycloalkyl radicals are, for example, cycloproyol, cyclopentyl, cyclohexyl, cyclooctanyl and bicyclooctyl. 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. The cycloalkenyl radicals preferably have 3 to 8 carbon atoms and particularly preferably 5 to 6 carbon atoms. Suitable cycloalkenyl radicals are, for example, cyclopentenyl, cyclohexenyl and cyclooctenyl.

Substituted cycloalkyl and substituted cycloalkenyl radicals are cycloalkyl and cycloalkenyl radicals wherein one or more hydrogen atoms of one 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, SiIyI, thio, seleno and combinations thereof. Examples of substituted cycloalkyl and cycloalkenyl radicals are 4-dimethylaminocyclohexyl and 4,5-dibromocyclohept-4-enyl.

For the purposes of the present application, aryl is to be understood as meaning aromatic radicals which have a single aromatic ring or several aromatic rings which are condensed, linked via a covalent bond or by a linking unit such as a methylene or ethylene unit. Such linking moieties may also be carbonyl moieties, such as in benzophenone, or oxygen moieties, such as in diphenyl ether, or nitrogen moieties, such as in diphenylamine. The aryl radicals preferably have 6 to 20 carbon atoms, more preferably 6 to 8 carbon atoms, and especially preferably 6 carbon atoms. Examples of aromatic rings are phenyl, naphthyl, diphenyl, diphenyl ether, diphenylamine and benzophenone. Substituted aryl radicals are aryl radicals in which one or more hydrogen atoms bound to carbon atoms of the aryl radical are replaced by one or more groups such as alkyl, alkenyl, alkynyl, substituted alkyl, substituted alkenyl, substituted alkynyl, cycloalkyl, cycloalkenyl, substituted cycloalkyl, substituted cycloalkenyl, heterocyclo, substituted heterocyclo, halogen, halo-substituted alkyl (eg CF ₃ ), hydroxy, amino, phosphino, alkoxy and thio. In addition, one or more hydrogen atoms attached to carbon atoms of the aryl group may be bonded through one or more groups, such as saturated and / or unsaturated cyclic hydrocarbons, which may be fused to the aromatic ring (s) be linked, or linked together by a suitable group. Suitable groups are those described above. Under heteroaryl according to the present application, the above-mentioned aryl compounds to understand in which one or more carbon atoms of the radical by a heteroatom, for. B. N, O or S are replaced.

Heterocyclo in the present application means a saturated, partially unsaturated or unsaturated cyclic radical in which one or more carbon atoms of the radical have been replaced by a heteroatom such as N, O or S. 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 bonded to one of the ring atoms are substituted by one or more groups such as halogen, alkyl, substituted alkyl, aryl, substituted aryl, heteroaryl, substituted heteroaryl, alkoxy , Aryloxy, boryl, phosphino, amino, SiIyI, thio, seleno are replaced.

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 and SiIyI. Suitable alkoxy radicals are, for example, methoxy, ethoxy, benzyloxy and t-butoxy.

By the term aryloxy are meant those radicals of general formula -OZ ² wherein Z ^{2 is} selected from aryl, substituted aryl, heteroaryl, substituted heteroaryl and combinations thereof. Suitable aryloxy radicals and heteroaryloxy radicals are phenoxy, substituted phenoxy, 2-pyridinoxy and 8-quinolinoxy.

Amino radicals are radicals of the general formula -NZ ³ Z ⁴ in which Z ³ and Z ⁴ are selected independently of one another from hydrogen, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, heterocycloalkyl, substituted heterocycloalkyl, aryl, substituted aryl, Heteroaryl, substituted heteroaryl, alkoxy, aryloxy and SiIyI.

Preferred aromatic and heteroaromatic hydrocarbons used in the amination process according to the invention are benzene, naphthalene, diphenylmethanes, anthracene, toluene, xylene, phenol and aniline, and also pyridine, pyrazine, pyridazine, pyrimidine and quinoline.

In a preferred embodiment, therefore, at least one hydrocarbon from the group benzene, naphthalene, diphenylmethane, anthracene, toluene, xylene, phenol and aniline and pyridine, pyrazine, pyridazine, pyrimidine and quinoline is used. It is also possible to use mixtures of said aromatic or heteroaromatic hydrocarbons. Particular preference is given to using at least one aromatic hydrocarbon from the group consisting of benzene, naphthalene, anthracene, toluene, xylene, phenol and aniline, very particularly preferably benzene, toluene and naphthalene.

Benzene is particularly preferably used in the process according to the invention. As the aliphatic hydrocarbon, methane is particularly preferred for use in the process of the present invention.

Amination Reagent: According to the invention, the reactant stream E contains at least one aminating reagent. Suitable aminating reagents are those which introduce at least one amino group into the hydrocarbon used for direct amination. Examples of preferred aminating reagents are ammonia, primary and secondary amines and compounds which split off ammonia under the reaction conditions. It is also possible to use mixtures of two or more of the abovementioned amination reagents.

In particular, preferred amination reagent is ammonia. Aminokohlenwasserstoffe:

In the process according to the invention, a reactant stream E which comprises at least one hydrocarbon and at least one aminating reagent is converted to a reaction mixture R which contains at least one amino hydrocarbon and hydrogen. At least one corresponding to the hydrocarbon used corresponding amino hydrocarbon is obtained which contains at least one amino group more than the hydrocarbon used. For the purposes of the present invention, aminohydrocarbon is therefore to be understood as meaning the reaction product of the hydrocarbons used in the process with the aminating reagent. In this case, at least one amino group is transferred from the aminating reagent to the hydrocarbon. In a preferred embodiment, 1 to 6 amino groups, in a particularly preferred embodiment 1 to 3 amino groups, very particularly preferably 1 to 2 amino groups and particularly preferably 1 amino group are transferred to the hydrocarbon. The number of amino groups transferred can be controlled by the molar ratio between amination reagent and hydrocarbon to be aminated and by the reaction temperature. Typically, the ratio of amination reagent to hydrocarbon is 0.5 to 9, preferably 1 to 5, more preferably 1, 5 to 3. In the event that in the process according to the invention as a hydrocarbon benzene and as amination ammonia in a molar ratio in the range of 1 to 9 are used, is obtained as the amino hydrocarbon aniline.

If toluene is used as the hydrocarbon in the process according to the invention and ammonia in the molar ratio in the range from 1 to 9 is used as the aminating reagent, toluene diamine is obtained as the aminohydrocarbons.

In the event that methane is used in the process according to the invention as the hydrocarbon and ammonia in a molar ratio in the range from 1 to 9 as the aminating reagent, methylamine, dimethylamine or trimethylamine or a mixture of two or more of the abovementioned amines is obtained as aminohydrocarbyl ,

In a particular embodiment, benzene is reacted with ammonia to aniline. In another special embodiment, toluene is reacted with ammonia to form toluenediamine.

Catalysts: The direct amination is carried out in the presence of at least one catalyst.

As catalysts, in principle, all known amination catalysts are suitable. Catalysts which may be used are those known for the direct amination of hydrocarbons, in particular those known for the direct amination of benzene with ammonia to form aniline. Such catalysts are described in the patent literature, for example, in WO 2007/099028, WO 2007/096297, WO 2000/69804, WO 2008/009668, WO 2007/025882, US Pat. No. 3,919,155, US Pat. No. 3,929,889, US Pat. No. 4,001,260, US Pat. No. 4,031,106, and US Pat WO 99/10311 described. Since, according to the process of the invention, the removal of the hydrogen takes place electrochemically and not by chemical conversion in the reaction system, it is also possible to use catalysts which have no components which are reactive toward hydrogen.

As catalysts, for example, conventional metal catalysts based on

Nickel, iron, cobalt, copper, precious metals or alloys of these metals are used. Preferred noble metals (EM) are Ru, Rh, Pd, Ag, Ir, Pt and Au. In a particular embodiment, the noble metals Ru and Rh do not become alone, but used in alloy with one or more other transition metals, such as Co, Cu, Fe and nickel. Examples of suitable catalysts are supported NiCuEM; CoCuEM; NiCoCuEM, NiMoEM, NiCrEM, NiReEM, CoMoEM, CoCrEM, Co-ReEM, FeCuEM, FeCoCuEM, FeMoEM, FeReEM alloys. In this case, EM is a deliming metal, preferably Pt, Pd, Ag, Ir, particularly preferably Ag and / or Ir. Further particularly preferred is NiCuEM, wherein EM is selected from Pt, Pd, Ag and / or Ir.

In one embodiment, the electrocatalyst (electrode) used on the retentate side simultaneously serves as a catalyst for the conversion of hydrocarbon to aminocarbon (amination catalyst). In another embodiment, the amination catalyst may be attached directly to the electrocatalyst. In this case, the hydrogen released in the reaction is discharged directly from the catalyst surface of the amination catalyst through the proton-conducting membrane.

The catalyst can be used in generally conventional form, for example as a powder or for use in a fixed bed in the form of strands, spheres, tablets or rings. The catalytically active constituents can be present on a carrier material. Examples of suitable carrier materials are inorganic oxides, for example ZrO ₂ , SiO ₂ , Al ₂ O ₃ , MgO, TiO ₂ , B ₂ O ₃ , CaO, ZnO, BaO, ThO ₂ , CeO ₂ , Y ₂ O ₃ and mixtures thereof Oxides, such as magnesium aluminum oxide, preferably TiO ₂ , ZrO ₂ , Al ₂ O ₃ , magnesium aluminum oxide and SiO ₂ into consideration. Particularly preferred are Al ₂ O ₃ , ZrO ₂ and magnesium aluminum oxide. ZrO ₂ is understood as meaning both pure ZrO ₂ and the normal Hf-containing ZrO ₂ .

The catalysts preferably used in the process according to the invention can be regenerated, for example by passing a reductive atmosphere over the catalyst or by first passing an oxidative and then a reductive atmosphere over or through the catalyst bed. As the reductive atmosphere, an H ₂ atmosphere is preferably used.

Reaction Conditions Directamination:

The direct amination can be carried out under oxidative or non-oxidative conditions. The direct amination can also be carried out under catalytic or non-catalytic conditions.

In a preferred embodiment, the directamination takes place in the presence of a catalyst under non-oxidative conditions. Non-oxidative according to the present invention in terms of direct amination means that the concentration of oxidants such as oxygen or nitrogen oxides in the educts used (Eduktstrom E) below 5 wt .-%, preferably below 1 wt .-%, more preferably below 0.1 wt .-% (in each case based on the total weight of the reactant stream E). Educt stream E is understood in the context of the present invention to mean the stream which is conducted to the reactor and contains at least one hydrocarbon and at least one aminating reagent. Most preferably, the reactant stream E is free of oxygen. Also particularly preferred is a concentration of oxidant in the reactant stream E, which is equal to or less than the concentration of oxidizing agents in the source from which the hydrocarbons and aminating reagents used originate.

The reaction conditions in the direct laminating process according to the invention depend inter alia on the hydrocarbon to be aminated and the catalyst used. The direct amination is generally carried out at temperatures of 20 to 800 ⁰ C, preferably 50 to 700 ⁰ C, particularly preferably 70 to 350 ⁰ C.

The reaction pressure in the directamination is preferably 0.5 to 40 bar, preferably 1 to 6 bar, particularly preferably 1 to 3 bar, in particular atmospheric pressure.

The residence time in the case of discontinuous process control in the amination process according to the invention is generally from 15 minutes to 8 hours, preferably from 15 minutes to 4 hours, particularly preferably from 15 minutes to 1 hour. When carried out in a 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 "residence time" in this context means the residence time of the reactant stream E on the catalyst, for fixed bed catalysts 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 of the amination reagent depends on the amination reaction carried out and the reaction conditions. Generally, at least stoichiometric amounts of the hydrocarbon and the amine reagent are used. Preferably, one of the reactants will be used in stoichiometric excess to achieve equilibrium shift to the desired product side and thus higher conversion. Preferably, the Aminnierungsreagenz is used in stoichiometric excess with respect to the hydrocarbon. The ratio of amination reagent to hydrocarbon is 0.5 to 9, preferably 1 to 5, particularly preferably 1, 5 to 3. Hydrogen separation:

In the process according to the invention, at least part of the hydrogen contained in the reaction mixture R is separated off electrochemically. The reaction mixture R is understood to mean the mixture which is formed by the chemical reaction of at least one hydrocarbon with at least one amination reagent. The reaction mixture therefore usually contains as reaction products the corresponding amino hydrocarbons and hydrogen. Optionally, the reaction mixture R may further contain unreacted starting materials. The hydrogen is separated by means of a gas-tight membrane-electrode assembly, wherein the hydrogen to be separated is transported in the form of protons through the membrane. The electrodes with the membrane interposed therebetween are called Membrane Electrode Assembly (MEA). The reaction mixture R is guided along one side of the membrane. This page is called retentate page below. The other side of the membrane is referred to below as the permeate side. On this page, the hydrogen formed in sub-step b1) and the water formed in sub-step b2) are removed.

According to the invention, the MEA has at least one selectively proton-conducting membrane. The membrane has at least one electrode catalyst on each side, in the context of this description the electrode catalyst located on the retentate side being referred to as anode catalyst, and the electrode catalyst located on the permeate side as cathode catalyst. On the retentate side, the hydrogen is oxidized to protons at the anode catalyst, these pass through the membrane and are partially reduced to hydrogen (b1) on the permeate side of the cathode catalyst and partially converted to water to produce electrical energy with oxygen (b2); in substep b2), an oxygen-containing stream O is guided along the permeate side and brought into contact with the membrane. In sub-step b1), electrical energy must be expended through the membrane for the transport of the protons, which energy is supplied by applying a DC voltage to the two sides of the membrane by means of electrodes.

In a preferred embodiment, the hydrogen is separated directly from the reaction mixture R. Furthermore, the hydrogen is preferably separated off directly from the reaction zone RZ, in which the reaction mixture R is formed.

Reaction zone RZ in the context of the present invention is to be understood as the region in which the chemical reaction of at least one hydrocarbon and at least one aminating reagent takes place for the reaction mixture R. The separation of hydrogen according to the inventive process may be from ⁰ C at temperatures of 20 to 800, are preferably carried out from 50 to 700 ⁰ C, particularly preferably from 70 to 350 ⁰ C. When using MEAs based on polyvinyl lybenzimidazol and phosphoric acid, the separation is carried out preferably at 130 to 200 ⁰ C. When using ceramic membranes, for example based on ammonium polyphosphate, it is possible to work at temperatures of 250 to 350 ^° C.

The separation of the hydrogen by the process according to the invention is preferably carried out at pressures of from 0.5 to 10 bar, preferably from 1 to 6 bar, more preferably from 1 to 3 bar, in particular at atmospheric pressure. According to a preferred embodiment of the invention, the pressure difference between the retentate and the permeate side of the membrane is below 1 bar, preferably below 0.5 bar, more preferably there is no pressure difference.

The separation of the hydrogen is brought about by the formation of a potential difference between the two sides of the membrane by applying a voltage according to the invention. The separation is carried out at voltages from 0.05 to 2000 mV, preferably from 100 to 900 mV, particularly preferably from 100 to 800 mV, measured against a hydrogen reference electrode (RHE).

According to the invention, at least part of the hydrogen formed in the direct amination is separated off. Preferably at least 30%, more preferably at least 50%, more preferably at least 70%, and most preferably at least 95%, especially at least 98% are separated off.

The hydrogen obtained on the permeate side contains at most 5 mol%, preferably at most 2 mol% and particularly preferably at most 1 mol% of hydrocarbons. In addition, the hydrogen may contain up to 30 mol%, preferably up to 10 mol%, particularly preferably up to 2 mol%, of water, depending on the selectively proton-conducting membrane used. The presence of water is required with some types of membranes, for example, certain polymer membranes to moisten the polymer membrane. According to a preferred embodiment, the separation of the hydrogen from the reaction mixture R is carried out in a reactor which is equipped with at least one gas-tight MEA in such a way that the reaction zone RZ is on the retinal side of the membrane or forms. In one embodiment, the separation can be carried out, for example, in a reactor whose outer walls are at least partially formed from gas-tight MEAs. The separated hydrogen can still be dried prior to further use, this is carried out in particular if the separation takes place through a polymer membrane which has to be moistened. reactors:

In the process according to the invention, it is possible to use all reactor types which are suitable for direct lamination reactions and which have been modified by at least one gas-tight MEA.

Suitable reactors are thus tubular reactors, fixed bed reactors, membrane reactors, fluidized bed reactors, moving beds, circulating fluidized beds, Salzbadreaktoren, plate heat exchanger reactors, Horden reactors with multiple hordes with / without heat exchange or withdrawal / supply of partial streams between the Hor-, in possible embodiments as radial flow or axial flow reactors, wherein in each case the reactor suitable for the desired reaction conditions (such as temperature, pressure and residence time) 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 process according to the invention can be carried out as a semi-continuous reaction or a 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 fixed bed reactor or fluidized bed reactor which has been modified according to the invention with at least one MEA.

Elektrodenkatalvsatoren:

The function of electrode catalyst is z. See, for example, Journal of Power Sources 177 (2008), 478-484, KA Perry, GA Eisman, BC Benicewicz "Electrochemical hydrogen pumping using a high-temperature polybenzimidazole (PBI) membrane." To ensure good contact of the membrane with that on the Retentate side hydrogen and ensure good removal of the separated hydrogen on the permeate side, the electrode layers are usually contacted with gas distribution layers., These are, for example, plates with a lattice-like surface structure of a system of fine channels or layers of porous material such as nonwoven fabric or fabric The entirety of gas distribution layer and electrode layer is generally referred to as gas diffusion electrode (GDE) the gas distribution layer, the hydrogen to be separated on the retentate side is guided close to the membrane and the anode catalyst and facilitated on the permeate side, the removal of the hydrogen formed. Depending on the embodiment of the invention, the anode can simultaneously serve as an anode catalyst and the cathode at the same time as a cathode catalyst. However, it is also possible to use different materials for the anode and the anode catalyst or the cathode and the cathode catalyst. In one embodiment of the invention, the anode catalyst may also serve as an amination catalyst at the same time. In this case, the anode catalyst is formed from at least one material of the abovementioned amination catalysts. The customary materials known to the person skilled in the art can be used for producing the electrodes, for example Pt, Pd, Cu, Ni, Ru, Co, Cr, Fe, Mn, V, W, tungsten carbide, Mo, molybdenum carbide, Zr, Rh, Ag, Ir, Au, Re, Y, Nb, electrically conductive forms of carbon such as carbon black, graphite and nanotubes, and alloys and mixtures of the foregoing elements.

The anode and the cathode may be made of the same material or of different materials. The anode catalyst and the cathode catalyst may be selected from the same or different materials. Particularly preferred as the anode / cathode combination are Pt / Pt, Pd / Pd, Pt / Pd, Pd / Pt, Pd / Cu, Pd / Ag, Ni / Pt, Ni / Ni and Fe / Fe.

As electrode catalyst material it is possible to use the customary compounds known to the person skilled in the art and elements which can catalyze the dissociation of molecular hydrogen into atomic hydrogen, the oxidation of hydrogen into protons and the reduction of protons to hydrogen. Suitable examples are Pd, Pt, Cu, Ni, Ru, Fe, Co, Cr, Mn, V, W, tungsten carbide, Mo, molybdenum carbide, Zr, Rh, Ag, Ir, Au, Re, Y, Nb and alloys and mixtures of these, Pd, Pt and Ni are preferred according to the invention. The elements and compounds mentioned above as the electrode catalyst material may also be present in a supported state, preference being given to using carbon as the carrier.

According to a preferred embodiment of the present invention, carbon containing conductive material electrodes is preferably used. In this case, the carbon and an electrode catalyst are preferably applied to a porous support such as fleece, fabric or paper. The carbon can be mixed with the catalyst or first the carbon and then the catalyst are applied.

According to a further embodiment of the invention, the electrically conductive material used as the electrode and the electrode catalyst are applied directly to the membrane.

Membranes: The membrane is preferably formed as a plate or as a tube, wherein the usual, known from the prior art for the separation of gas mixtures membrane arrangements can be used, for example, tube bundle or plug-in membrane. The MEA used in the invention is gas-tight, that is, it has virtually no porosity, can pass through the gases in atomic or molecular form from one side to the other side of the MEA, nor does it have mechanisms by the gases nonselectively, for example by adsorption, Solution in the membrane, diffusion and desorption can be transported through the MEA. The tightness of the membrane-electrode assembly (MEA) can be ensured either by a gas-tight membrane, by a gas-tight electrode or a gas-tight electrode catalyst and by a combination thereof. For example, as a gas-tight electrode, a thin metallic foil may be used, for example, a Pd, Pd-Ag or Pd-Cu foil. Furthermore, the membrane used according to the invention selectively conducts protons, that is to say in particular that it is not electron-conducting.

According to the invention, it is possible to use for the membranes all materials known to those skilled in the art, from which it is possible to form selectively proton-conducting membranes. These include, for example, the materials listed by J.W. Phair and S.P.S. Badwal in London (2006) 12, pages 103-115. Also selectively proton-conducting membranes, as they are known from fuel cell technology, can be used according to the invention.

For example, the following ceramic membranes such as certain heteropolyacids such as H ₃ Sb ₃ B ₂ O ₄ • 10H ₂ O, H ₂ Ti ₄ O ₉ • 12H ₂ O and HSbP ₂ O ₈ • 10 H ₂ O; Acid zirconium silicates, phosphates and phosphonates in layered structure such as

K ₂ ZrSi ₃ O ₉ , K ₂ ZrSi ₃ O ₉ , alpha-Zr (HPO ₄ ) ₂ • nH ₂ O, gamma-Zr (PO ₄ ) - (H ₂ PO ₄ ) • 2H ₂ O, alpha and gamma Zr sulfophenyl phosphonate or sulfoaryl phosphonate; not stratified

Oxide hydrates such as antimony acid (Sb ₂ O ₅ • 2H ₂ O), V ₂ O ₅ • nH ₂ O, ZrO ₂ • nH ₂ O, SnO ₂ • nH ₂ O and Ce (HPO ₄ ) ₂ • nH ₂ O are used. Furthermore, oxo acids and

Salts containing, for example, sulfate, selenate, phosphate, arsenate, nitrate groups, etc. to be used. Particularly suitable are Oxoanionensysteme based on phosphates or complex heteropolyacids such as polyphosphate, aluminum polyphosphate, ammonium polyphosphate and polyphosphate compositions such as NH ₄ PO 3 / (NH ₄₎ ₂ SiP ₄ OI3 and NH ₄ PO ₃ ₂ O ZTiP. ₇ Furthermore, oxidic materials can be used, such as brownmillerites, fluorites and phosphates with apatite structure, pyrochlore minerals and perovskites. In general, all proton-conducting materials, such as zeolites, aluminosilicates, xAl ₂ O ₃ (1 -X) SiO ₂ , SnP ₂ O ₇ ,

Sn _1-x ln _x P ₂ O ₇ (X = 0.0-0.2). Perovskites have the basic formula AB _1-x M _x O _3-y , where M is a trivalent rare earth element that serves for doping and y denotes the oxygen deficiency in the perovskite oxide lattice. For example, A may be selected from Mg, Ca, Sr and Ba. Among others, B can be selected from CeZr and Ti. For A, B and M, different elements from the respective groups can also be selected independently of one another.

Furthermore, structurally modified glasses can be used, such as chalcogenide glasses, PbO-SiO ₂ , BaO-SiO ₂ and CaO-SiO ₂ . Further suitable proton-conducting ceramics and oxides are described, for example, in Solid State Ionics 125, (1999), 271-278; Journal of Power Sources 180, (2008), 15-22; Ionics 12, (2006), 103-115; Journal of Power Sources 179 (2008) 92-95; Journal of Power Sources 176 (2008) 122-127 and Electrochemistry Communications 10 (2008) 1005-1007.

Examples of proton-conducting ceramics and oxides are SrCeO ₃ , BaCeO ₃ , Yb: SrCeO ₃ , Nd: BaCeO ₃ , Gd: BaCeO ₃ , Sm: BaCeO ₃ , BaCaNdO ₉ , Y: BaCeO ₃ , Y: BaZrCeO ₃ , Pr-doped Y BaCeO ₃ , Gd: BaCeO ₃ , BaCe ₀ , 9Yo, i0 ₂ , ₉₅ (BYC), SrCe ₀ , 95Ybo, o5θ _3-α , BaCe ₀ , 9Ndo, io0 _3-α ,

(α denotes the number of oxygen vacancies per formula unit of the perovskite oxide); Sr-doped La ₃ P ₃ O ₉ , Sr-doped LaPO ₄ , BaCe ₀ , ₉ Yo, i0 _3-α (BCY), BaZr ₀ , ₉ Y ₀ , 10 _3-α (BZY), Ba ₃ Cai, i ₈ Nbi, ₈₂ O _8, ₇₃ (BCN 18), (Lai, ₉₅ Cao, o ₅₎ Zr ₂ 0 _7-α, La ₂ Ce ₂ O _7, Eu ₂ Zr ₂ O _7, H ₂ S / (B ₂ S ₃ or Ga ₂ S ₃ ) / GeS ₂ , SiS ₂ , As ₂ S ₃ or CsI; BaCeo, ₈ Gdo, ₂ 0 _3-α (BCGO); Gd-doped BaCeO ₃ such as BaCe ₀ , ₈₅ Yo, i5θ _3-α (BCY15) and BaCe ₀ , ₈ Sm ₀ , ₂ O _3-α , XAl ₂ O ₃ (1-X) SiO ₂ , SnP ₂ O ₇ , Sn _1- nln _x P ₂ O ₇ (x = 0.0 - 0.2).

Another class of materials suitable for the preparation of gas tight and selectively proton conducting membranes are polymer membranes. Suitable polymers include sulfonated polyetheretherketone (S-PEEK), sulfonated polybenzoimidazoles (S-PBI) and sulfonated fluorocarbon polymers (NAFION ^®). Furthermore, perforated polysulfonic acids, styrene-based polymers, poly (arylene ether), polyimides and polyphosphazenes are used. It can be used that are based on polybenzimidazole and phosphoric acid, as sold for example under the name Celtec-P ^® from BASF SE also Polybenzamidazolen. According to the invention, the above-mentioned ceramic membranes are preferably used as materials for the selectively proton-conducting membrane.

When polymer membranes are used, they are usually wetted by the presence of about 0.5 to 30% by volume of water on at least one side of the membrane.

Processing of the product stream:

After the separation of the hydrogen from the reaction mixture R by means of at least one MEA, a product stream P is obtained. This contains at least one amino hydrocarbon and optionally unreacted starting materials, such as hydrocarbons and aminating reagents, and optionally not separated hydrogen. In a preferred embodiment, the product stream P contains less than 500, preferably less than 200, and most preferably less than 100 ppm of hydrogen.

Optionally, further hydrogen can be separated from the product stream P. For this purpose, the product stream P is brought into contact again with one or more MEAs in a subsequent step. In a preferred embodiment, however, the separation of the hydrogen from the reaction mixture is so complete that a subsequent separation of hydrogen from the product stream P is not necessary.

In a process variant (variant I), the amino hydrocarbon and the amination reagent are separated from the product stream P. The order of separation is freely selectable. Preferably, however, only the amination reagent and then the amino hydrocarbon is separated off. The reclaimed stream S1 thus obtained contains the unreacted hydrocarbon. In a preferred embodiment, this is used again in the direct lamination. The hydrocarbon from stream S1 is either added to the educt stream E or directly recycled to the reaction zone. The separation of aminocarbon and Aminierungsreagenz can be carried out according to well-known, familiar to the expert methods, for example by condensation, distillation or extraction. The choice of the pressure and temperature range depends on the physical properties of the compounds to be separated and is known to the person skilled in the art. Thus, the product stream P at 50 ⁰ C to 250 ⁰ C, preferably at 70 ⁰ C to 200 ⁰ C, particularly preferably at 80 ⁰ C to 150 ⁰ C, at pressures in the range of 0 to 5 bar, preferably 0.5 to 2 bar, more preferably 0.8 to 1, 5 bar and cooled in particular at atmospheric pressure. In this case, the amino hydrocarbons condense, while unconverted hydrocarbon and amination reagent and optionally still present hydrogen in gaseous form and thus can be separated by conventional methods, for example with a gas-liquid separator. The liquid components thus obtained contain the amino hydrocarbon and unreacted hydrocarbon, the separation of amino hydrocarbon and hydrocarbon also takes place by methods known in the art, such as distillation, rectification or acid extraction. The amounts of hydrocarbon and amination reagent added to recycled recycle stream S1 are selected to maintain the molar ratios of hydrocarbon and amination reagent required for the direct amination.

In the case of the direct amination of benzene and ammonia to aniline and hydrogen, the product stream P contains essentially aniline, unreacted benzene and ammonia, and optionally byproducts and residues of hydrogen. According to variant I, the product stream P is first separated by condensation into a gaseous phase containing ammonia and optionally radicals of hydrogen, and a liquid phase containing aniline and benzene. The liquid phase is subsequently separated by distillation, rectification or acid extraction into aniline and benzene. The benzene (stream S1) is reused in the direct lamination. The aniline thus obtained may optionally be subjected to further work-up steps.

According to a further process variant (variant II), the product stream P is used again in the direct lamination. For this purpose, the product stream P can be admixed with the Edutkstrom E or introduced separately directly into the reaction zone RZ. In a preferred embodiment, the product stream P is fed back as long as in the reaction zone RZ until it has enriched in the product stream P, a concentration of amino hydrocarbon, which allows economical processing. The product stream P is preferably recycled one to twenty times, preferably one to ten times, more preferably one to five times, and particularly preferably one to three times, to the reaction zone RZ. In this procedure, the quantities of hydrocarbon and amination reagent fed in to the recycled product stream P are selected such that the MoI ratios of hydrocarbon and amination reagent required for the directamination are maintained. The work-up and separation of the amino hydrocarbon takes place according to the method described under variant I.

According to a further process variant (variant III), the aminohydrocarbyl is separated from the product stream P. The reclaimed stream S2 obtained in this process variant contains unconverted hydrocarbon and amination reagent. This reclaimed stream S2 can be reused in direct lamination. For this purpose, the worked-up product stream can be admixed with the educt stream E or introduced directly into the reaction zone RZ. The separation of the amino hydrocarbon takes place by methods known to the person skilled in the art, for example by condensation, distillation or acid extraction. In variant III, the aminohydrocarbyl is preferably removed from the product stream P by acid extraction. The amounts of hydrocarbon and amination reagent added to the recycled product stream P are selected such that the molar ratios of hydrocarbon and amination reagent required for the directamination are maintained.

The invention is explained in more detail by the following examples, without being limited thereto. example 1

Direct amination of benzene at 300-350 ⁰ C with in situ separation of H ₂ as gas directly from the reaction zone, Pt-GDE / ELAT as anode catalyst In an electric cell at a temperature of 300-350 ⁰ C benzene and ammonia (Eduktstrom E ). The cell contains a gas-tight MEA with sufficient active area. The proton-conducting membrane of the MEA is ammonium polyphosphate. As electrodes of the MEA, gas diffusion electrodes ELAT (1 mg / cm ² platinum) from BASF Fuel Cell GmbH are used both for the anode and for the cathode. In addition, on the retentate side of the electric cell an amination catalyst of a carbon fabric containing finely dispersed NiCu alloy (about 3 to 5 mg / cm ² ) installed, this catalyst layer was attached directly to the ELTA gas diffusion electrode. The MEA therefore has a layer structure with - starting on the retentate side - the following layer sequence:

1. Amination catalyst comprising a carbon fabric containing finely dispersed NiCu alloy (about 3 to 5 mg / cm ² ),

2. ELAT gas diffusion electrode,

3. proton-conducting membrane (ammonium polyphosphate) and 4. ELAT gas diffusion electrode.

At the anode of the MEA, a voltage (U _A ) in the range of +250 to + 800 mV is applied. The hydrogen is oxidized on the retentate side at the anode to protons, these pass through the membrane and are reduced to hydrogen at the cathode.

The reactor discharge (reaction mixture R) gives a mixture of benzene, aniline, hydrogen, nitrogen and ammonia. A large part of the hydrogen is separated directly from the reaction zone by means of the electromembrane and thus the equilibrium conversion of benzene to aniline is increased.

Example 2

Direct amination of benzene at 300-350 ⁰ C with in situ separation of H ₂ as gas directly from the reaction zone, Pd-FoNe as anode catalyst

In an electric cell (reactant stream E) are introduced at a temperature of 300 to 350 ⁰ C and ammonium benzene monia. The cell contains a gas-tight MEA with sufficient active area. The proton-conducting membrane of the MEA is ammonium polyphosphate. Palladium foil (manufacturer Goodfellow, thickness 10 μm) is used as the anode electrode of the MEA, and the cathode used is a gas diffusion electrode ELAT with Pt loading of 1 mg / cm ² (manufacturer BASF Fuel Cell GmbH). The advantage of Pd film is that it is gas-tight and thus offers protection of the ceramic membrane from ammonia. In addition, an amination catalyst made of carbon fabric containing finely dispersed NiCu alloy (about 3 to 5 mg / cm ² ) is incorporated on the retentate side of the electrical cell, this catalyst layer is applied directly to the Pd film.

The MEA therefore has a layer structure with - starting on the retentate side - the following layer sequence:

2. Palladium foil (manufacturer Goodfellow, thickness 10 μm),

3. proton-conducting membrane (ammonium polyphosphate) and

4. Gas diffusion electrode ELAT with Pt loading of 1 mg / cm ² . At the anode of the MEA, a voltage (U _A ) in the range of +250 to +800 mV is applied. The hydrogen becomes proton oxide on the retentate side at the anode. diert, these pass through the membrane and are reduced at the cathode to hydrogen.

The reactor discharge is a mixture of benzene, aniline, hydrogen, nitrogen and ammonia. A large part of the hydrogen is separated directly from the reaction zone by means of the electromembrane and thus the equilibrium conversion of benzene to aniline is increased.

Example 3

Direct amination of benzene at 300-350 ⁰ C with in situ separation of H ₂ directly from the reaction zone and recovery of electrical energy, Pt-GDE / ELAT as anode catalyst In an electric cell at a temperature of 300-350 ⁰ C benzene and ammonia (Educt current E) registered. The cell contains a gas-tight MEA with sufficient active area. The proton-conducting membrane of the MEA is ammonium polyphosphate. As electrodes of the MEA, gas diffusion electrodes ELAT (1 mg / cm ² platinum) from BASF Fuel Cell GmbH are used both for the anode and for the cathode. In addition, an amination catalyst made of a carbon fabric containing finely dispersed NiCu alloy (about 3-5 mg / cm ² ) is incorporated on the retentate side of the electric cell, this catalyst layer is attached directly to the ELAT gas diffusion electrode. The MEA therefore has a layer structure with - starting on the retentate side - the following layer sequence:

2. ELAT gas diffusion electrode,

3. proton-conducting membrane (ammonium polyphosphate) and

4. ELAT gas diffusion electrode.

The reaction mixture R contains benzene, aniline, hydrogen, nitrogen and ammonia and is conducted along the anode side of the electric cell. Oxygen (or air) is introduced into the electric cell on the cathode side. On the retentate side of the hydrogen at the anode catalyst is oxidized to protons, these traverse the membrane and react on the permeate side of the cathode catalyst with the oxygen to water. The driving force is the reduction of oxygen. In the overall reaction, energy is released in the form of heat and by interposing a consumer in the form of electrical current. The reactor discharge on the anode side gives a mixture of benzene, aniline, hydrogen, nitrogen and ammonia. A large part of the hydrogen is separated directly from the reaction zone by means of the electromembrane and thus the equilibrium conversion of benzene to aniline is increased.

Example 4

Direct amination of benzene at 300-350 ⁰ C with in situ separation of H ₂ directly from the reaction zone and recovery of electrical energy, Pd-FoNe as anode catalyst

In an electric cell benzene and ammonia (reactant stream E) are added at a temperature of 300 to 350 ⁰ C. The cell contains a gastight MEA with sufficient active area. The proton-conducting membrane of the MEA is ammonium polyphosphate. Palladium foil (manufacturer Goodfellow, thickness 10 μm) is used as the anode electrode of the MEA, and the cathode used is a gas diffusion electrode ELAT with Pt loading of 1 mg / cm ² (manufacturer BASF Fuel Cell GmbH). The advantage of Pd film is that it is gas-tight and thus offers protection of the ceramic membrane from ammonia. In addition, an amination catalyst consisting of carbon fabric containing finely dispersed NiCu alloy (about 3-5 mg / cm ² ) is incorporated on the retentate side of the electrical cell, this catalyst layer being introduced directly onto the Pd foil. The MEA therefore has a layer structure with - starting on the retentate side - the following layer sequence:

2. Palladium foil (manufacturer Goodfellow, thickness 10 μm),

3. proton-conducting membrane (ammonium polyphosphate) and

4. Gas diffusion electrode ELAT with Pt loading of 1 mg / cm ² .

The reaction mixture R contains aniline, hydrogen, nitrogen and ammonia and is passed along on the anode side of the electric cell. Oxygen (or air) is introduced into the electric cell on the cathode side. On the retentate side of the hydrogen at the anode catalyst is oxidized to protons, these traverse the membrane and react on the permeate side of the cathode catalyst with the oxygen to water. The driving force is the reduction of oxygen. In the overall reaction, energy is released in the form of heat and by interposing a consumer in the form of electrical current. The reactor discharge on the anode side gives a mixture of benzene, aniline, hydrogen, nitrogen and ammonia. A large part of the hydrogen is separated from the reaction zone by means of the electromembrane directly from the reaction zone and thus the equilibrium conversion of benzene to aniline is increased.

Example 5

Effectiveness of the Electromembrane in the Separation of Hydrogen from H ₂ / N ₂ Gas Mixtures

In an electric cell containing a gas-tight MEA with 45 cm ² active area, 80 l / h of nitrogen and 0.5 l / h of hydrogen (hydrogen concentration 6200 ppm) were added. As a membrane of the MEA CeltecP ^® (polyimidazole / phosphoric acid) of BASF Fuel Cell GmbH is used. As electrodes of the MEA, gas diffusion electrodes ELAT (1 mg / cm ² platinum) from BASF Fuel Cell GmbH are used both for the anode and for the cathode. The electric cell was operated at 190 ⁰ C and 1 bar pressure. At the anode of the MEA, a voltage (U _A ) of +250 mV was applied. In the discharge of the electric cell on the anode side, 40 ppm of hydrogen and nitrogen (balance) were present. This corresponds to a hydrogen separation of 99.4%.

Example 6 In Table 1, the effectiveness of the hydrogen separation of Example 5 is compared with Comparative Examples of the prior art.

Table 1 :

Comparative Example 2 Reference # 55 in Ind. Eng. Chem. Res. 2006, 45, 875-881; Comparative Example 3 Reference # 189 in Top. Catal. (2008) 51: 107-122;

Comparative Example 4 Reference # 158 in Top. Catal. (2008), 51: 107-122.

Claims

claims

1. A process for the direct amination of hydrocarbons to aminocarbons by reacting a reactant stream E, which contains at least one carbon hydrogen and at least one amination reagent, to a reaction mixture R, containing amino hydrocarbon and hydrogen in a reaction zone RZ, and electrochemical separation of at least a part of in the reaction of hydrogen formed from the reaction mixture R by means of a gas-tight membrane-electrode assembly having at least one selectively proton-conducting membrane and on each side of the membrane at least one electrode catalyst, wherein on the retentate side of the membrane at least a portion of the hydrogen on the Anodenkatalysator is oxidized to protons and the protons after passing through the membrane on the permeate side of the cathode catalyst partially according to

b1) are reduced by applying a voltage to hydrogen and partially according to

2. The method according to claim 1, characterized in that the hydrogen is separated from the reaction mixture R directly from the reaction zone RZ.

3. The method according to claim 1 or 2, characterized in that at least a part of the electric current generated in b2) in b1) is used.

4. The method according to any one of claims 1 to 3, characterized in that the current required for the separation of the hydrogen according to b1) by b2) is generated.

5. The method according to any one of claims 1 to 4, characterized in that in the hydrogen separation, the pressure difference between the retentate and the permeate side of the membrane is below 1 bar and preferably below 0.5 bar.

6. The method according to any one of claims 1 to 5, characterized in that the hydrogen separation according to b1) at voltages of 0.05 to 2000 mV, preferably from 100 to 900 mV, particularly preferably from 100 to 800 mV, is performed.

7. The method according to any one of claims 1 to 6, characterized in that is used as the oxygen-containing stream O air.

8. The method according to any one of claims 1 to 7, characterized in that the electrodes of the membrane-electrode assembly are designed as gas diffusion electrodes.

9. The method according to any one of claims 1 to 8, characterized in that the electrodes of the membrane-electrode assembly are designed as metallic foils.

10. The method according to any one of claims 1 to 9, characterized in that as a selectively proton-conducting membrane membranes selected from the group

Ceramic membranes and polymembranes are used.

1 1. A method according to any one of claims 1 to 10, characterized in that the anode catalyst on the retentate simultaneously the Aminierungskataly- sator for the implementation of hydrocarbons for the direct amination of

Hydrocarbons to amino hydrocarbons is.

12. The method according to any one of claims 1 to 1 1, characterized in that after separation of at least a portion of the hydrogen, a product stream P is obtained, are separated from the amino hydrocarbon and Aminierungsreagenz, wherein a recycled stream S1 is formed, which is used again in the Direktaminierung becomes.

13. The method according to any one of claims 1 to 1 1, characterized in that after separation of at least a portion of the hydrogen, a product stream P is obtained, is separated from the amino hydrocarbon, wherein a recycled stream S2 is formed, which is used again in the Direktaminierung.

14. The method according to any one of claims 1 to 1 1, characterized in that after separation of at least a portion of the hydrogen, a product stream P is obtained, which is used again in the Direktaminierung.

15. The method according to any one of claims 1 to 12, characterized in that is used as the hydrocarbon methane and aminating reagent as ammonia, and as the amino hydrocarbon at least one amine from the group methylamine, dimethylamine and trimethylamine is formed.