EP2021125A1

EP2021125A1 - Novel supported catalyst for ammoxidation

Info

Publication number: EP2021125A1
Application number: EP07728395A
Authority: EP
Inventors: Hartmut Hibst; Sabine Huber; Frank Rosowski
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2006-04-28
Filing date: 2007-04-23
Publication date: 2009-02-11
Also published as: US20090118531A1; WO2007125052A1; KR20090007464A; CN101432067A

Abstract

The present invention relates to a process for preparing an aromatic or heteroaromatic nitrile in the presence of a supported catalyst which comprises a support having a mean diameter of = 78 µm. The present invention further relates to the novel supported catalyst as such and to a process for preparing this novel supported catalyst.

Description

New supported catalyst for the ammoxidation

description

The present invention relates to a process for the preparation of an aromatic or heteroaromatic nitrile in the presence of a supported catalyst containing a support with a mean diameter <78 microns. Furthermore, the present invention relates to the novel supported catalyst as such and to a process for the preparation of this novel supported catalyst.

Processes for the preparation of aromatic nitriles such as orthophthalonitrile (OPDN) or isophthalonitrile (IPN) are known. Such processes, which are carried out in the presence of a catalyst by reaction with ammonia and oxygen, are also referred to as ammoxidation or ammoxidation. For example, DE-A 21 64 401, DE-A 26 53 380 or EP-A 1 319 653 describe processes for the preparation of IPDN starting from meta-xylene using chromium-containing catalysts, where IPDN is partly used as an intermediate for preparing the corresponding diamino Compound serves by hydrogenation. However, the use of chromium-containing catalysts is problematic because they are carcinogenic (chromate dusts) and thus also represent a major environmental problem.

As alternatives to the chromium-containing catalysts, in particular catalysts are used for the preparation of aromatic nitriles, which are vanadium and / or antimony-containing, and may optionally have further metals. Thus, EP-A 0 750 942 relates to particulate catalysts for use in a fluidized bed. The catalyst particles (the carrier) have a diameter in the range of 5 to 500 microns to 90 or more wt .-% (weight percent). Of these catalyst particles, in turn, those having a diameter of 20 to 75 μm have a specific breaking strength, in terms of breaking load, which is expressed in a specific formula. However, EP-A 0 750 942 does not disclose that the carrier material consists of particles having a mean diameter <78 μm.

From EP-A 222 249 is another process for the preparation of aromatic nitriles from alkyl-substituted aromatic hydrocarbons by catalytic oxidation with ammonia and oxygen or oxygen-containing gases at elevated temperature in the vapor phase in the presence of a catalyst containing 2 to 10 wt .-% Vanadium pentoxide, 1 to 10 wt .-% antimony trioxide, 0.02 to 2 wt .-% alkali oxide and 0.01 to 1 wt .-% alkaline earth metal oxide on alumina, known. The catalysts used therein have particle sizes with a diameter from 0.05 to 0.3 mm, specific ranges in terms of the average diameter of the particles are not disclosed in EP-A 222 249. This applies in the same way to the catalysts described in DE-A 37 00 710, which are used in a fluidized bed process.

EP-A 0 699 476 describes supported catalysts which are suitable for the ammoxidation. The supported catalysts comprise as support material essentially alumina, silica, titania and / or zirconia and as the active composition vanadium and antimony in oxidic form as essential components. The carrier material is spherical or approximately spherical and has a bulk density of 0.6 to 1.2 kg / l. As further metal components of the active composition, the supported catalysts may, for example, cesium and / or rubidium and tungsten in each case in oxidic form. As a concrete embodiment, EP-A 0 699 476 describes the ammoxidation of ortho-xylene to OPDN, wherein the spherical alumina support used has an average diameter of 150 μm.

EP-A 0 767 165 relates to a process for the preparation of aromatic or heteroaromatic nitriles, wherein a very similar composition is used with regard to the active catalyst components (active composition) as in the catalysts described in EP-A 0 699 476. However, the carrier of these supported catalysts described in EP-A 0 767 165 consists of 2 to 30 grain fractions (particle fraction) whose average diameter differs by 10 to 80% and wherein the carrier has a bulk density of 0.6 to 1.2 kg / l having. As concrete embodiments, the ammoxidation of ortho-xylene is described to OPDN, wherein carriers are used from mixtures of spherical alumina with average diameters of 150 microns and 80 microns. However, EP-A 0 767 156 does not disclose that the average diameter of the catalyst support particles can be <78 μm.

In WO 05/28417 and WO 05/26104 further catalysts are described which can be used in the ammoxidation of meta-xylene to IPDN. The catalysts described therein contain vanadium, antimony and / or chromium, wherein no information on the average diameter of the catalyst particles are disclosed. In a specific embodiment, the ammoxidation of meta-xylene on a catalyst containing vanadium, antimony, tungsten and cesium on steatite to IPDN is described.

The object underlying the invention is therefore to provide an improved catalyst or an improved process for the preparation of aromatic or heteroaromatic nitriles by ammoxidation. According to the invention, this object is achieved by a novel catalyst or a new and improved process using the novel catalyst for preparing an aromatic or heteroaromatic nitrile of the general formula (I)

in the

Methyl X is nitrogen or CR ⁶ and R ^1, R ^2, R ^3, R ^4, R ⁵ and R ⁶ are independently hydrogen, Ci-Cβ-alkyl, halogen, trifluoro, nitro, amino, cyano, -C ₇ cyanoalkyl, C 1 -C ₈ -aminoalkyl or hydroxy, with the proviso that at least one of the substituents is cyano or C 1 -C ₇ -cyanoalkyl,

by reacting an aromatic or heteroaromatic hydrocarbon of the general formula (II)

in the

X 'nitrogen or CR ^6' and

R ^{1 '} , R ^2' , R ^{3 '} , R ^4' , R ^{5 '} and R ⁶ independently of one another are hydrogen, C ¹ -C ⁶ -alkyl, halogen, trifluoromethyl, nitro, amino, C ¹ -C ⁶ -aminoalkyl or hydroxy, with the proviso that at least one of the substituents is C 1 -C ₈ -alkyl,

mean, with ammonia and oxygen and / or an oxygen-containing gas at a temperature of 200 to 600 ° C and a pressure of 0.1 to 5 bar in the gas phase over a supported catalyst containing 0.5 to 20 wt .-% vanadium oxide contains, characterized in that the supported catalyst contains a carrier having a mean <78 microns and the carrier has a bulk density of 0.6 to 1, 2 kg / l. The process according to the invention or the catalysts according to the invention used therein have the advantage that a higher space-time yield can be achieved compared to the known prior art ammoxidation processes due to the improved carrier geometry. This is achieved in an advantageous manner in the ammoxidation of aromatics, in particular of ortho- and meta-xylene to OPDN or IPDN. The new catalysts, even at higher load (higher xylene concentration in the feed and / or higher xylene throughput), can achieve higher xylene conversions and higher value product selectivities compared to conventional catalysts. This has a positive effect on the costs incurred for dinitrile production. These advantages are particularly evident when the catalysts according to the invention are used in a fluidized-bed process, since the catalysts according to the invention show an improved fluid behavior due to the smaller carrier geometry.

The process according to the invention can be carried out as follows:

A mixture of an aromatic or heteroaromatic hydrocarbon, ammonia and oxygen and / or an oxygen-containing gas can in the gas phase at temperatures of 200 to 600 ° C, preferably 300 to 550 ° C, more preferably 350 to 500 ° C and a pressure of 0.1 to 5 bar, preferably 0.3 to 2 bar, more preferably 0.5 to 1, 5 bar, in particular at atmospheric pressure (atmospheric pressure) in the presence of the supported catalyst according to the invention, which is defined below, are reacted. In the process according to the invention, the educts are preferably reacted in a fluidized bed.

The starting compounds (aromatic or heteroaromatic hydrocarbons of the general formula (M)) are preferably taken up in a gas stream of ammonia, oxygen and / or an oxygen-containing gas such as air, their concentration advantageously being from 0.1 to 25% by volume, preferably 0.1 to 10% by volume.

Another object of the present invention are supported catalysts as such, which can be used in the process according to the invention. The inventive carrier catalysts contain

i) at least one support with an average diameter <78 μm, the support having a bulk density of 0.6 to 1.2 kg / l, preferably 0.6 to 1.1 kg / l, particularly preferably 0.7 to 1, Has 0 kg / l and ii) 0.5 to 20 wt .-% vanadium oxide (calculated as vanadium (V) oxide). As further components, the supported catalysts according to the invention may contain:

iii) 0 to 20% by weight of antimony oxide (calculated as antimony (III) oxide), iv) 0 to 4% by weight of one or more alkali or alkaline earth oxides, preferably

Cesium oxide, rubidium oxide or mixtures thereof, in particular cesium oxide and v) 0 to 10 wt .-% of one or more oxides from the group tungsten, molybdenum,

Titanium, iron, cobalt, nickel, manganese, potassium or copper.

In the supported catalyst according to the invention, the support constitutes 60 to 99% by weight of the total catalyst composition.

In the supported catalysts according to the invention, it is possible in principle to use all carriers known to the person skilled in the art, preferably carriers of aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, silicon carbide, magnesium oxide or mixtures thereof, preferably aluminum oxide, silicon oxide, titanium oxide, zirconium oxide or mixtures thereof, particularly preferably aluminum oxide , Silica or mixtures thereof, most preferably alumina.

The components ii) to v) are contained in the supported catalyst according to the invention in the following amounts. The following preferred amounts for components iii) to v) relate only to those embodiments in which these optional components are included.

ii) 0.5 to 20% by weight, preferably 1 to 12% by weight, more preferably 1 to 10% by weight

%, more preferably 3 to 7 wt .-% vanadium oxide, iii) 0 to 20 wt .-%, preferably 1 to 12 wt .-%, particularly preferably 2 to 10

Wt .-%, in particular 4 to 9 wt .-% antimony oxide, iv) 0 to 4 wt .-%, preferably 0.2 to 3 wt .-%, particularly preferably 0.5 to 1 wt .-% of one or more Alkali or alkaline earth oxides, preferably cesium oxide, rubidium oxide or mixtures thereof, in particular cesium oxide, v) 0 to 10 wt .-%, preferably 0.01 to 5 wt .-%, particularly preferably 0.1 to 3 wt .-% of one or a plurality of oxides from the group of tungsten, molybdenum, titanium, iron, cobalt, nickel, manganese or copper, preferably tungsten oxide or molybdenum oxide, in particular tungsten oxide (calculated as tungsten (VI) oxide).

Components ii) to v) are present in the supported catalysts according to the invention in amounts such that the support (component i)) contains from 60 to 99% by weight, preferably from 70 to 96% by weight, particularly preferably from 80 to 93% by weight. % of the total catalyst mass. The supported catalysts according to the invention preferably contain no chromium or chromium oxide, ie the catalysts according to the invention are chromium-free.

In a further preferred embodiment, the carrier catalysts according to the invention comprise:

ii) from 3 to 7% by weight of vanadium oxide, iii) from 4 to 9% by weight of antimony oxide, iv) from 0.5 to 1% by weight of cesium oxide and / or v) from 0.1 to 3% by weight of tungsten oxide.

The supported catalysts according to the invention contain at least one support (component i)) with an average diameter <78 μm. The mean diameter (particle diameter) is also referred to as the D ₅₀ value and defines the mean particle diameter of the individual carrier particles. This means that 50% by volume of the carrier particles have a smaller value than the average diameter. The D ₅₀ value is experimentally determined by means of a laser particle size analyzer from Cilas, Madison, WI, USA. In addition, the particle size spectrum of the carriers used is characterized by a sieve analysis. The average diameter of the carrier particles is preferably from 20 to 78 μm, more preferably from 20 to 75 μm, even more preferably from 40 to 75 μm, particularly preferably from 50 to 70 μm and very particularly preferably from 60 to 65 μm.

Another object of the present invention is a process for the preparation of the supported catalysts of the invention.

The supported catalysts may be prepared by simultaneously or successively impregnating or impregnating the support, with one or more solutions and / or suspensions, preferably with one or more aqueous solutions or one or more aqueous suspensions of one or more compounds containing the active catalyst components such as vanadium and optionally antimony, tungsten, molybdenum, titanium, iron, cobalt, nickel, manganese, copper, alkali metal or alkaline earth metal and subsequent drying and calcination tion, preferably under oxidizing conditions, at temperatures of 400 to 800 ° C, preferably 450 to 750 ° C. Preferably, the impregnating solution or suspension is not used in a greater amount than can be absorbed by the carrier material. You can also carry out the impregnation after each intermediate drying in several steps. As impregnating or impregnating solutions, the active components are generally used preferably in the form of aqueous solutions of their salts, in particular salts of organic acids which can be decomposed without residue in the oxidative calcination. Preferred are the oxalates, especially in the case of vanadium, and the tartrates, especially in the case of antimony and tungsten, where the tartrates may also be present in the form of mixed salts, eg together with ammonium ions. To prepare such solutions, it is possible to dissolve the metal oxides but also other metal compounds in the acids.

The substituents R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ^{1 '} , R ^2' , R ^{3 '} , R ^4' , R ^{5 '} , R ^6' and the intermediate member X and X ' in the general formula (I) or (II) have the following meanings:

X is nitrogen or CR ⁶ , preferably CR ⁶ ,

X is nitrogen or CR ^{6 '} , preferably CR ^6' ,

R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ^{1 '} , R ^2' , R ^{3 '} , R ^4' , R ^{5 '} and R ^{6' are} independently

Is hydrogen, C 1 -C 6 -alkyl, preferably C 1 -C ₄ -alkyl, particularly preferably methyl, ethyl, n-propyl and isopropyl,

Halogen, such as fluorine, chlorine, bromine or iodine, preferably fluorine, chlorine or bromine, particularly preferably chlorine or bromine, in particular chlorine,

trifluoromethyl,

Nitro, - Amino,

C 1 -C ₈ -iminoalkyl, preferably C 1 -C ₄ -aminoalkyl, particularly preferably amino-methyl, 1-aminoethyl and 2-aminoethyl, and

Hydroxy, with the proviso that in the general formula (II) at least one of the substituents is C _r C ₈ -alkyl,

R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ additionally independently

Cyano, - CrC ₇ cyanoalkyl, preferably dC ₃ cyanoalkyl, particularly preferably cyano methyl, 1-cyanoethyl and 2-cyanoethyl, with the proviso that at least one, that is 1, 2, 3, 4, 5 or 6, preferably 1, 2 or 3, more preferably 1 or 2 of the substituents for cyano or CrC ₇ -

Cyanoalkyl stands. For example, in the above definitions, C 1 -C 6 -alkyl means that the corresponding alkyl radical has between 1 and 8 carbon atoms.

In one embodiment of the present invention, the compound of formula (I) is preferably OPDN or IPDN, more preferably IPDN.

Of particular industrial importance is the ammoxidation for the production of OPDN from o-xylene, from isophthalonitrile from m-xylene (meta-xylene), from terephthalodi nitrile from p-xylene (para-xylene), from benzonitrile from toluene and from nicotinic acid nitrile beta-picoline.

In the case of xylene, the ammoxidation of the first methyl group proceeds faster than that of the second, so that it is also possible to obtain slightly partial anemonoxidation products, e.g. p-methylbenzonitrile from p-xylene, o-methylbenzonitrile from o-xylene and, optionally, benzonitrile as a by-product.

The present invention will become apparent from the following examples.

example 1

Preparation of a fluidized bed catalyst with the composition

V ₄ S b ₃ , 1 ₈ W ₀ , ₃₈ CSo, ₃₈ θ _x

In an externally heated 2-liter stirred apparatus, 237.1 g of oxalic acid dihydrate (BASF AG, D-67056 Ludwigshafen, content of H ₂ C ₂ O ₄ • 2 H ₂ ) are continuously stirred in 387.3 g of water O = 99.75 wt .-%) dissolved at 60 ° C. 90.1 g of polyvanadate (from GfE, Gesellschaft für Elektrometallurgie, D-90431 Nuremberg, content of V ₂ O ₅ = 89.5% by weight) are slowly dissolved in the solution, the temperature of the resulting mixture A being 90 ° C increases.

In a further externally heated 0.3 liter stirred apparatus, while stirring in 70 g of water, 16.8 g of cesium nitrate (Chemetall, D-60323 Frankfurt, content of CsNO ₃ = 98.2% by weight) are added. dissolved at 60 ° C, the solution B is obtained.

In a further externally heated 2-liter stirred apparatus, with continuous stirring in 210 g of water, 226.0 g of tartaric acid (Brennkat GmbH GmbH, D-67663 Kaiserslautern, content of H ₆ C ₄ O ₆ = 99.75 % By weight) at 60 ° C. (D-10247 Berlin Fa Antraco. Sb ₂ O ₃ content = 99.9 wt .-%) are dissolved in the solution obtained 102.7 g of antimony (III) oxide was added and heated to 90 ° C. 252.0 g of ammonia water (Bernd Kraft GmbH, D-47167 Duisburg, NH ₃ content = 25.0% by weight) are then metered into the resulting suspension within 30 minutes, the resulting the temperature increase is limited by the rate of addition to + 2 ° C. The result is a nearly clear solution C.

Subsequently, the 60 ° C warm solution B is metered into the 90 ° C warm mixture A with continuous stirring. The resulting dark blue mixture D is heated to 90 ° C within 15 minutes. 20.9 g of ammonium paratungstate hydrate (from HC Starck, D-3380 Gosslar, content of WO ₃ = 89.25% by weight) are added to the resulting mixture D and the mixture is stirred at 90 ° C. for 15 minutes. Subsequently, the solution C is metered into the resulting mixture within 1 minute. The resulting mixture E is stirred for a further 10 minutes at 90.degree.

The carrier used is a Puralox carrier from Sasol, D-20537 Hamburg. The Puralox support consists of round alumina particles (Al ₂ O ₃ content = 96.5 wt .-%), has a BET specific surface area of 131 m ² / g and has a bulk density of 0.78 g / cm ³ . The D ₅₀ value of the particle diameter is 62.4 μm and shows the following particle size distribution in the sieve analysis:

Particle diameter <25 μm = 0.2% by weight

Particle diameter <45 μm = 16.9 wt.% Particle diameter <90 μm = 86.6 wt.%

The pore volume of the carrier has a value of 0.38 cm ³ / g, the average pore diameter is 11, 7 nm. The water absorption capacity of the carrier is determined by the incipient-wetness method and is 0.6 cm ³ / g.

2000 g of this Puralox carrier are placed in a mixer (type RO2) from Eirich GmbH & Co KG, D-74732 Hardheim. With continuous mixing (rotating pot, mixing speed of the mixing stirrer at level 1), the mixture E is metered into the mixer within 10 minutes, wherein the mixture E is completely absorbed by the presented Puralox carrier. The resulting powder is subsequently mixed in the mixer at a higher mixing speed of the mixing stirrer (stage 2).

The resulting, dark gray powder is distributed on porcelain dishes with a bed height of 2 cm and dried in an oven at 100 ° C overnight. The water absorption of the dried powder P is determined by the incipient wetness method to 0.4 cm ³ / g.

In a 1 liter stirred apparatus which can be heated from the outside, 101.6 g of oxalic acid dihydrate (BASF AG, D-67056 Ludwik) are added while stirring in 166.0 g of water. hafen; Content of H ₂ C ₂ O ₄ ^• 2 H ₂ O = 99.75 wt .-%) at 60 ° C dissolved. 38.6 g of polyvanadate (from GfE, Gesellschaft für Elektrometallurgie, D-90431 Nuremberg, content of V ₂ O ₅ = 89.5% by weight) are slowly dissolved into the solution, the temperature of the mixture obtained being A ' 90 ° C increases.

7.2 g of cesium nitrate (Chemetall, D-60323 Frankfurt, content of CsNO ₃ = 98.2% by weight) are further stirred in 30 g of water in a further externally heatable 0.1 liter stirring apparatus. dissolved at 60 ° C, the solution B 'is obtained.

In a further externally heated 0.5 liter stirred apparatus, 96.87 g of tartaric acid (Brennkat GmbH, D-67663 Kaiserslautern, content of H ₆ C ₄ O ₆ = 99.75 % By weight) at 60 ° C. 44.0 g of antimony (III) oxide (from Antraco, D-10247 Berlin, Sb ₂ O ₃ -Gel IIaIt = 99.9% by weight) are added to the resulting solution and the mixture is heated to 90.degree. Subsequently, in the suspension obtained 108.0 g of ammonia water (Bernd Kraft GmbH, D-47167 Duisburg;. NH ₃ content = 25.0 wt .-%) dosed within 30 minutes, the resulting temperature rise by the speed Addition is limited to + 2 ° C. The result is a nearly clear solution C.

Subsequently, the 60 ° C warm solution B 'is metered into the 90 ° C warm mixture A' with continuous stirring. The resulting dark blue mixture D 'is heated to 90 ° C within 15 minutes. 8.94 g of ammonium paratungstate hydrate (from HC Starck, D-3380 Gosslar, content of WO ₃ = 89.25% by weight) are added to the resulting mixture D 'and the mixture is stirred at 90 ° C. for 15 minutes. Subsequently, the solution C is metered into the resulting mixture within 1 minute. The resulting mixture E 'is diluted with 300 ml of water and stirred for a further 10 minutes at 90 ° C.

In a mixer (type RO2) from Eirich GmbH & Co KG, D-74732 Hardheim, the powder P prepared above is added. With continuous mixing (rotating pot, mixing speed of the mixing stirrer at level 1), the mixture E 'is metered into the mixer within 10 minutes, wherein the mixture is completely absorbed by the submitted powder P. The resulting powder is subsequently mixed in the mixer at a higher mixing speed of the mixing stirrer (stage 2). The resulting, dark gray powder is distributed on porcelain dishes with a bed height of 2 cm and dried in an oven at 100 ° C overnight. The powder is then in 200-g portions in a rotary kiln in a rotating quartz glass ball (revolution speed = 8 rpm) with 50 Nl / h of air over, heated to 330 ° C within 1 hour, 2 hours at 330 ° C held. heated to 560 ° C within 1 hour and kept at 560 ° C for 1 hour. Subsequently, the oven is switched off, so that the powder can cool in the rotating quartz glass ball. The yellow catalyst powder obtained has a BET specific surface area of 127 m ² / g and a pore volume of 0.33 cm ³ / g, the average pore diameter is 16.4 nm. The bulk density is 0.81 g / cm ³ . The active material contained in the carrier material has the composition V ₄ Sb _{3 18} W ₀ 3βCso38θχ. The weight fraction of the active composition on the catalyst (= support + active material) is 13.3%. The specific gravity of the catalyst is 5.1 g / cm ³ .

Example 2 Comparative Example for Production of a Fluid Bed Catalan

The carrier used is Puralox from the company Sasol, consisting of round alumina particles having an Al ₂ O ₃ content of 98.7% by weight. The carrier has an average particle diameter D ₅₀ of 150 μm. The sieve analysis leads to the following particle size distribution: particle diameter <100 μm = 2.5% by weight

Particle diameter <200 μm = 94.0% by weight

Particle diameter <300 μm = 99.2% by weight

- Particle diameter <500 microns = 100 wt .-%.

The BET specific surface area is 129 m ² / g. The pore volume has a value of 0.37 cm ³ / g, the average pore diameter is 1 1, 6 nm. The bulk density is 0.76 g / cm ³ .

The yellow catalyst powder prepared from this support in analogy to Example 1 and with the same chemical composition has a specific surface area of 121 m ² / g. The pore volume is 0.33 cm ³ / g. The average pore diameter is 16.6 nm. The bulk density has a value of 0.78 g / cm ³ .

Example 3 In an electrically heated fluidized bed reactor m-xylene, air, ammonia and VE (demineralized) water are fed. All reactants are previously, unless they are already present under normal conditions in the gaseous state, converted by vaporization in the gaseous state and introduced as an intimate mixture in the pre-heated fluidized bed reactor. The molar ratios of the educts used are:

Ratios of mol / mol

NH ₃ : m-xylene 14

NH ₃ : O ₂ 3,4

O ₂ : m-xylene 4.1

N ₂ : NH ₃ 1 In the fluidized bed reactor 400 g of the catalyst from Example 1 (D ₅₀ = 62.4 microns) are installed. The m-xylene throughput is 280 g / h. The GHSV (gas hourly space velocety) is 4000 / h. GHSV = [standard liters / (liter of catalyst • h)] with standard liters as the sum of all gaseous substances under standard conditions (25 ° C, 1 bar).

At a reactor temperature of 470 ° C., the following conversions (U) / selectivities (S) are obtained:

U (m-xylene) = 99% - S (IPDN) = 81%

S (TN) = 8%; TN = tolunitrile

Example 4

Comparative example for the use of a fluidized-bed catalytic converter: In the fluidized-bed reactor from Example 3, 800 g of the catalyst from Example 2 are incorporated (D ₅₀ = 150 μm). The m-xylene throughput is 167 g / h. The GHSV is 1200 / h.

U (m-xylene) = 90%

S (IPDN) = 68%

S (TN) = 14%

Example 4 shows that significantly poorer catalytic properties are achieved with the same active composition on a support with D ₅₀ = 150 μm even at a significantly lower GHSV value.

Claims

claims

1. Process for the preparation of an aromatic or heteroaromatic nitrile of the general formula (I)

in the

X nitrogen or CR ⁶ and

R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ independently of one another are hydrogen, C ¹ -C ⁶ -alkyl, halogen,

Trifluoromethyl, nitro, amino, cyano, C 1 -C ₄ cyanoalkyl, C 1 -C 4 aminoalkyl or hydroxy, with the proviso that at least one of the substituents is cyano or C 1 -C ₄ cyanoalkyl,

in the

X 'nitrogen or CR ^6' and

R ^{1 '} , R ^2' , R ^{3 '} , R ^4' , R ^{5 '} and R ⁶ independently of one another are hydrogen, C ¹ -C ⁶ -alkyl, halogen,

Trifluoromethyl, nitro, amino, C 1 -C 6 -alkyl or hydroxy, with the proviso that at least one of the substituents is C 1 -C 6 -alkyl, mean, with ammonia and oxygen or an oxygen-containing gas at a temperature of 200 to 600 ° C and a pressure of 0.1 to 5 bar in the gas phase over a supported catalyst containing 0.5 to 20 wt .-% vanadium oxide, characterized in that the supported catalyst contains a carrier having an average diameter <78 microns and the carrier has a bulk density of 0.6 to 1, 2 kg / l.

2. The method according to claim 1, characterized in that one carries out the reaction in the fluidized bed.

3. The method according to claim 1 or 2, characterized in that the carrier is selected from alumina, silica, titania, zirconia or mixtures thereof.

4. The method according to any one of claims 1 to 3, characterized in that the supported catalyst contains 0.5 to 20 wt .-% vanadium oxide and 0.5 to 20 wt .-% antimony oxide.

5. The method according to any one of claims 1 to 4, characterized in that the supported catalyst 0.5 to 20 wt .-% vanadium oxide and 0.5 to 20 wt .-% antimony oxide and 0.2 to 3 wt .-% cesium oxide, Rubidiumoxid or mixtures thereof contains.

6. The method according to any one of claims 1 to 5, characterized in that the nitrile of the general formula (I) is ortho-phthalonitrile (OPDN) or isophthalonitrile (IPDN).

7. containing supported catalyst

i) a support having an average diameter of <78 μm, the support having a bulk density of from 0.6 to 1.2 kg / l, ii) from 0.5 to 20% by weight of vanadium oxide, iii) from 0 to 20% by weight. Iv) 0 to 4% by weight of one or more alkali metal or alkaline earth metal oxides and v) 0 to 10% by weight of one or more oxides from the group of tungsten,

Molybdenum, titanium, iron, cobalt, nickel, manganese, potassium or copper,

wherein the carrier constitutes 60 to 99% by weight of the total catalyst mass.

8. supported catalysts according to claim 7, characterized in that one uses as a carrier alumina, silica, titania, zirconia or mixtures thereof.

9. supported catalysts according to claim 7 or 8, characterized in that the carrier has an average diameter of 50 to 70 microns.

10. Supported catalyst according to one of claims 7 to 9, characterized in that

ii) from 3 to 7% by weight of vanadium oxide, iii) from 4 to 9% by weight of antimony oxide, iv) from 0.5 to 1% by weight of cesium oxide and / or v) from 0.1 to 3% by weight of tungsten oxide

are included.

1 1. A process for the preparation of a supported catalyst according to any one of claims 7 to 10, characterized in that a carrier having a mean diameter <78 microns with a solution or suspension of one or more compounds containing the active catalyst components, simultaneously or sequentially soaked or impregnated and then dried and calcined at temperatures of 400 to 800 ° C.

12. The method according to claim 11, characterized in that is calcined under oxidizing conditions.

13. A process for preparing a supported catalyst according to claim 11 or 12, characterized in that one uses vanadium as oxalate and antimony as tartrate.