DE102008060340A1 - Production of lactams and carboxylic acid amides by Beckmann rearrangement of oximes in the presence of Nb catalysts - Google Patents

Abstract

The present invention relates to processes for the production of lactams such as epsilon-caprolactam, omega-laurolactam or carboxylic acid amides such as acetaminophenol (analgesic acetaminophen) and benzanilide by Beckmann rearrangement of the corresponding oximes in the presence of Nb impregnated catalysts such as Nb on SiO2 preferably in the Gas phase, but also in the liquid phase. The invention also describes the method of regeneration of these Nb-containing catalysts in oxidizing and non-oxidizing media 200 ° C to 600 ° C.

Description

Summary

The present invention relates to processes for the production of lactams such as ε-caprolactam, ω-laurolactam or carboxylic acid amides such as acetaminophenol (analgesic acetaminophen) and benzanilide by Beckmann rearrangement of the corresponding oximes in the presence of Nb impregnated catalysts such as Nb on SiO ₂ preferably in the gas phase, but also in the liquid phase.

The The invention also describes the method of regeneration these Nb-containing catalysts in oxidizing and non-oxidizing Media 200 ° C to 600 ° C.

State of the art

Nb-containing materials have shown remarkable activity in heterogeneously catalyzed processes, including the synthesis of fine chemicals. ( Chem. Rev., 99 (1999) 3603-3624, Cat. Today 8 (1990) 1 ). Patent ( US 5618512 ) further states that niobium-containing zeolites are useful for the oxidation of hydrocarbons such as olefins.

In Journal of Catalysis 260 (2008) 17 it is reported that catalysts consisting of materials of the MS family such as MCM-41, in which Nb is incorporated into the matrix of these materials, can be advantageously used for the Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam; Very high selectivities are obtained at high conversions. However, the production of such an Nb-incorporated MCM-41 catalyst is extremely expensive and expensive.

The present invention describes the production of lactams such as ε-caprolactam, ω-laurolactam or carboxylic acid amides such as acetamidophenol and acetanilide by Beckmann rearrangement of the corresponding oximes such as cyclohexanone oxime or cyclododecanone oxime or 4-hydroxyacetophenone oxime or benzophenone oximes preferably in the gas phase but also in the liquid phase in the presence of Nb-containing catalysts, wherein the Nb is applied to various inorganic and organic support materials such as SiO ₂ , SiO ₂ -Al ₂ O ₃ , TiO ₂ and ZrO ₂ . Moreover, the invention describes the regeneration of such catalysts.

For example, ε-caprolactam and ω-laurolactam are important monomers for the production of polyamides such as nylon-6 and nylon 12. Thus ε-caprolactam is replaced by a Beckmann rearrangement of cyclohexanone oxime in the presence of acidic media such as fuming sulfuric acid or oleum ( U.S. Patent 4,268,440 and 5304643 ) carried out. The neutralization of the reaction mixture with ammonia leads to disadvantageous and polluting formation of large quantities of ammonium sulfate. Other disadvantages include corrosion, toxicity and possibly other by-products such as cyanopentene, aniline and cyclohexanone. The same applies to the production of ω-laurolactam.

The above processes can be carried out by replacing the homogeneous sulfuric acid by Beckmann rearrangement in the gas phase with solid acidic catalysts. The solid acid catalysts in the gas-phase rearrangement include boric acid catalysts ( JP-A-53-37686 . JP-A-46-12125 ), Silica-alumina catalysts ( British Patent No. 881927 ), solid phosphoric acid catalysts ( British Patent No. -881956 . US 4359421 ), Mixed oxide catalysts ( Dongsen Mao et al., Journal of Molecular Catalysis A: Chemical 240 (2005) 164-171 ) and zeolite catalysts ( G. Heitmann et al., Applied Catalysis A: General, 185 (1999) 99-108 and J. Catalysis, 186 (1999) 12-19 . G. Dahlhoff et al. Catal. Rev. Sci. Eng., Volume 43, no. 4 (2001) 381-441 . US 3016315 . EP-1065167 ), wherein silica-rich zeolite catalysts are advantageously used for the ε-caprolactam production.

ε-caprolactam can also be prepared by various other methods than the Beckmann rearrangement reaction. G. Dahlhoff et al. (Catal. Rev. Sci. Eng., Volume 43, No. 4 (2001) 381-441 and U.S. Patent 6,252,068 ) show such other methods for the synthesis of ε-caprolactam, such as the cyclization of methyl-6-aminocaproate (Patent JP-A-2-215767 ), Reaction of 6-aminocapronitile with water ( US 5495016 ), Reaction of methyl 6-hydroxy caproate with ammonia in the presence of hydrogen and steam (Patent JP-A-9-3041 ) and by cleavage of oligomers of ε-caprolactam in a fluidized bed reactor ( US Patent 4683305 ). In addition, the article of W. Hölderich et al. a comprehensive overview of the different production methods ( Catal Rev-Sci. Eng 43 (2001) 381 ).

Furthermore, patent describes US 4767857 the production of ε-caprolactam by heating 6-aminocaproic acid ester. patent US 4963672 has shown that, for the production of ε-caprolactam, first 5-formylvaleric acid ester is hydrolyzed with a catalyst and water to give 5-formylvaleric acid. Thereafter, the 5-formylvaleric acid is reacted with ammonia, hydrogen, solvent and hydrogenation catalysts under an atmospheric pressure to 6-aminocaproic acid.

To Catalyst separation and removal of the ammonia will be the remaining Heated solution and reacted to ε-caprolactam.

Recently, in patent no. WO 2005/123669 (A1) described that ε-caprolactam can also be produced synthetically from natural products such as L-lysine, as starting material. Here, an L-lysine salt in a solvent such. As alcohol, used for the production of α-amino-ε-caprolactam. Subsequent deamination produces ε-caprolactam.

It It is also known that the Beckmann rearrangement in the gas phase of Cyclohexanonoxim to ε-caprolactam using solid catalysts such as beta zeolite, Y zeolite, mordenite and in particular Zeolites with MFI structure can be performed.

However, beta, y, mordenite and MFI zeolites in the H form or doped with rare earth metals or transition metals deactivate very rapidly by oligomer and polymer formation. Likewise, other by-products such as 5-cyanopent-1-ene, cyclohexanone and aniline are increasingly being formed on these catalysts ( US 6531595 . US 5354859 ).

In the gas phase Beckmann rearrangement of zeolite catalysts such. As the pentasil type (MFI structure), carbonaceous products can deposit on the Brönsted acid sites of the catalyst surface during the reaction and deactivate very rapidly ( G. Heitmann et al., Appl. Catal, 185 (1999) 99, J. Cat, 186 (1999) 12 and US 5403801 ).

Around these organic substances from the active centers of the catalyst To remove, the catalyst becomes at higher temperature regenerated. In this case, in the presence of oxidative gases as oxygen, the carbon compounds such. B. oligomers and Polymers removed from the active sites of the catalyst.

Patents ( EP-1028108 and US 6265574 ) show that the Beckmann rearrangement in the gas phase boron-containing zeolites, eg. B. B-MFI zeolite, a high conversion of cyclohexanone oxime and ε-caprolactam selectivity in the fluidized bed reactor have ( G. Dahlhoff, et al., Studies in Surface Science and Catalysis, 139 (2001) 335-342 . G. Heitmann et al., Journal of Catalysis 194 (2000) 122-129 . US 6531595 ).

The Main problem with the above processes in the presence of B-MFI catalysts is that after a certain reaction time By about 2 hours, the deactivation of the catalyst starts because carbonaceous substances such as oligomers and polymers on the active Deposit centers of the catalyst.

Also ω-laurolactam can be used on zeolitic heterogeneous catalysts by Beckmann rearrangement of Cyclododekanonoxim be prepared in the gas phase.

Such a method is in patent PCT / FR 2006/001399 described. In this process, similar problems occur as in the production of ε-caprolactam from cyclohexanone oxime by Beckmann rearrangement.

Consequently, a process had to be developed which allowed for rapid regeneration of the catalyst. This was achieved by continuous regeneration of the catalyst in a fluidized bed reactor, so as to regain the starting activity of the catalyst for high conversions and high selectivities to ε-caprolactam ( US 4968793 ). Therefore, the industrial process is carried out in a fluidized bed reactor with continuous regeneration of the catalyst in a second fluidized bed reactor similar to that used in fluid catalytic cracking (FCC) ( US 6265574 ). However, have J. Roeseler et al. found that the addition of water of up to 6 moles of water per mole of cyclohexanone oxime suppresses the deactivation of the catalyst ( J. Roeseler et al., Appl. Catal 144 (1996) 319-333 . US 5741904 . H. Ichihashi et al., Cat. Today 73 (2002) 23-28 ).

patent EP 0086543 and US 4472516 describes the method for improving the life of the B-MFI catalyst through the addition of Na ions. However, only a selectivity for ε-caprolactam of 58% is found. The lifetime of the Na ion-treated catalyst is about 15 hours, which is about 5 times longer than that of the untreated B-MFI zeolites. However, the formation of the by-product 5-cyanopent-1-ene, which is easily oligomerized and polymerized, is greatly promoted, and the result is thus unsatisfactory.

aims Research in this area are those disadvantages through the Provision of a method z. For the production of ε-caprolactam from cyclohexanone oxime to overcome by Beckmann rearrangement, cheaper Catalysts as the expensive zeolite catalysts used so far to develop, which are also more robust and one allow longer use before regeneration.

description

It has now surprisingly been found that cheap and easy to prepare Nb-containing catalysts on support material also an excellent catalytic performance for the Beckmann rearrangement z. B. in the gas phase and very high Selectivity in sales of greater deliver as 95%. The lifetime of such catalysts is surprisingly long enough for commercialization in fixed bed reactors is possible and the process technology of an expensive fluidized bed reactor with continuous catalyst regeneration in a second fluidized bed can be avoided.

To In the present invention, the Beckmann rearrangement is preferred in the gas phase but also in the liquid phase impregnated on Nb amorphous materials with large surface and weak acidity carried out. These Catalysts show a constant activity, for example based on the cyclohexanone oxime reaction and on the extremely high selectivity to ε-caprolactam.

The invention also relates to the preparation of such catalysts by impregnation of Nb on support materials such as SiO ₂ , SiO ₂ -Al ₂ O ₃ , TiO ₂ and ZrO ₂ .

In the present invention, for. For example, on a catalyst charged with 3.15% by weight of Nb on a SiO _{2 support} , a conversion of cyclohexanone oxime of 100% and more than 95% of caprolactam selectivity at 300 ° C., 0.1 bar and 0.3 h ^{. 1} WHSV achieved in a fixed bed reactor. This invention relates not only to Nb-impregnated SiO ₂ catalysts but also to other Nb-impregnated catalysts.

Other inorganic support materials such as SiO ₂ with different surface area, different pore size and pore distribution and different Akzidität are amorphous SiO ₂ -Al ₂ O ₃ , TiO ₂ , ZrO ₂ , zeolites such as isomorphously substituted pentasil zeolites (eg., B-MFI, TS-1 , Al-MFI), mesoporous materials of the MS family such as MCM-41, MCM-48 and oxides of III. Main group elements such as Al ₂ O ₃ and B ₂ O ₃ as well as oxides of the lanthanum group such as La ₂ O ₃ or CeO ₂ . These other carrier materials also differ in their different surface, pore size and pore distribution as well as their different acitivity.

Of the Nb content in the prepared catalysts varies in a wide range between 0.1 wt .-% and 30 wt .-%, preferably between 0.5% by weight and 10% by weight, and more preferably between 1 Wt .-% and 5 wt .-%.

The Nb is applied by standard methods of catalyst preparation z. B. i.) By dissolving a Nb salt in water, impregnating on the substrate and spun off the excess Water on a rotary evaporator, ii.) By impregnation according to the "incipient wetness" method iii.) Ion exchange iv.) But also by mixing the niobium compound with the carrier followed by drying and calcination. The application of the Nb component usually closes a drying between 80 ° C and 160 ° C and then a calcination at 300 ° C to 750 ° C, preferably at 500 ° C to 600 ° C.

Of the Process for the preparation of lactams such as ε-caprolactam and ω-laurolactam in the present invention, by Beckmann rearrangement the corresponding oximes such as cyclohexanone oxime or cyclododecanone oxime in the gas phase in a continuously operated fixed bed reactor on a Nb-containing catalyst. Alternative to the fixed bed can Also fluidized bed reactors or fluidized bed reactors with continuous Regeneration in a second fluidized bed or moving bed reactors (Moving Bed) or plate reactors are used.

The same process concepts apply to the preparation of carboxylic acid amides by gas phases Beckmann rearrangement z. From 4-hydroxyacetophenone oxime to acetamino-phenol or from benzophenone oxime to benzanilide.

Of the Catalyst can be used in these processes in the form of tablets, extrudates or Wirbelgut be used.

The Reaction temperature is usually 200-500 ° C, preferably 250-350 ° C, more preferably 275-325 ° C.

The loading of the catalyst z. Example, with cyclohexanone oxime or 4-Hydroxyacetophenonoxim, expressed by the "space-time velocity" equal to WHSV (weight hourly space velocity) indicated in g oxime / hr and g catalyst is usually between 0.05 to 15 h ^-1 , preferably between 0 , 1 and 5 h ^-1 and more preferably 0.2 to 2.5 h ^-1 .

In In the present invention, the pressure in the reactor is between 0.01 up to 10 bar, but preferably between 0.05-2 bar and especially preferably between 0.1-0.5 bar.

The Oxime such as cyclohexanone oxime or cyclododecanone oxime in polar and / or non-polar solvents such as methanol, Ethanol, isopropanol, butanol, cyclohexanol, xylene, toluene or Benzene dissolved and used as a solution become. Supported the use of an inert solvent the transport of the oxime to the reactive centers of the catalyst and also facilitates desorption of the products from the catalyst surface. But the use of water and steam is a great advantage in carrying out the reactions.

Furthermore, carrier gases can be used. Such are inert gases such as N ₂ , argon, helium, CH ₄ and / or CO ₂ . The function of the carrier gas is the displacement of the reaction products and unreacted oxime from the catalyst surface.

In the gas-phase reaction on fixed bed occur carbonaceous by-products such as oligomers and polymers, which are the active sites of the catalyst occupy and deactivate the catalyst. The catalyst regeneration can be carried out in a fixed bed reactor. alternative to the fixed bed can also be fluidized bed reactors or. moving bed reactors (moving bed) or plate reactors are used.

In the present invention, the regeneration takes place at temperatures of 200 to 700 ° C, preferably at 450 to 550 ° C in the presence of oxidative gases or gas mixtures such as air and / or pure oxygen and / or oxygen with admixed inert gases N ₂ , argon , Methane, carbon dioxide and H ₂ .

Regeneration is also possible in a non-oxidative medium such as N ₂ , argon, methane, carbon dioxide and H ₂ at temperatures of 200 to 700 ° C, preferably 450 to 550 ° C. In doing so, the carbonaceous deposits at the active sites are blown away from the catalyst surface.

in the In general, the catalyst regeneration in the presence of oxidative gas such as air at high temperatures react strongly exothermic. In the presence of oxidative gases heat is released, causing the catalyst heats up a lot. The catalyst can in these sintering at high temperatures and irreversibly deactivated. The advantage of catalyst regeneration in the presence of a non-oxidizing Gases is that with this method no heat through the Oxidation of organic deposits released on the catalyst is, whereby adverse effects on the catalyst as in the oxidative regeneration can not occur.

Without that the production must be interrupted, the Beckmann rearrangement and catalyst regeneration in parallel in two fixed bed reactors can be performed. These two fixed bed reactors be in parallel in constant change between reaction and regeneration operated.

The Beckmann rearrangement of the oximes according to the invention on the novel Nb-containing heterogeneous catalysts can also be carried out in the liquid phase.

The process for the preparation of lactams such as ε-caprolactam and ω-laurolactam in the present invention is carried out by Beckmann rearrangement of the corresponding oximes such as cyclohexanone oxime or cyclododecanone oxime in the liquid phase in a continuously operated fixed bed reactor on a Nb-containing catalyst. Alternative to the fixed bed can also be batch reactors (Stirred Tank Reactor), autoclaves, Cascade reactors or trickle-bed reactors are used.

selbige Process concepts apply to the preparation of carboxylic acid amides by liquid phases Beckmann rearrangement z. From 4-hydroxyacetophenone oxime to acetaminophen or from benzophenone oxime to benzanilide.

Of the Catalyst will be used in these processes in powder form.

The Reaction temperature is usually 20-200 ° C, preferably 50-100 ° C.

The Loading the catalyst z. With cyclohexanone oxime or 4-hydroxyacetophenone oxime in the liquid takes place in the range of 2 g of oxime per 1 g of catalyst to 100 g of oxime per 1 g of catalyst.

In In the present invention, the pressure in the reactor is between 0.5 up to 10 bar, but preferably between 1-2 bar.

The Oxime such as cyclohexanone oxime or cyclododecanone oxime in polar and / or non-polar solvents such as methanol, Ethanol, isopropanol, butanol, cyclohexanol, xylene, toluene or Benzene dissolved and used as a solution become. But also the use of water and steam can be of great To be an advantage in carrying out the reactions. The weight ratio from substrate to solvent is in the range of 1: 1 to 1:15, preferably from 1: 6 to 1: 9.

Furthermore, the liquid phase Beckmann rearrangement under an inert gas atmosphere as in N ₂ , argon, helium, CH ₄ and / or CO ₂ can be performed.

Also in the liquid phase reaction occur carbonaceous By-products such as oligomers and polymers on which the active sites of the catalyst and deactivate the catalyst. In contrast to Gas phase reaction, the regeneration takes place here after separation the catalyst can be external to the reaction vessel be carried out in a fixed bed reactor.

In the present invention also here, the regeneration takes place at temperatures of 200 to 700 ° C, preferably at 450 to 550 ° C in the presence of oxidative gases or gas mixtures such as air and / or pure oxygen and / or oxygen with admixed inert gases N ₂ , Argon, methane, carbon dioxide and H ₂ .

Regeneration is also possible in a non-oxidative medium such as N ₂ , argon, methane, carbon dioxide and H ₂ at temperatures of 200 to 700 ° C, preferably 450 to 550 ° C. In doing so, the carbonaceous deposits at the active sites are blown away from the catalyst surface.

in the In general, the catalyst regeneration in the presence of oxidative gas such as air at high temperatures react strongly exothermic. In the presence of oxidative gases heat is released, causing the catalyst heats up a lot. The catalyst can in these sintering at high temperatures and irreversibly deactivated. The advantage of catalyst regeneration in the presence of a non-oxidizing Gases is that with this method no heat through the Oxidation of organic deposits released on the catalyst is, whereby adverse effects on the catalyst as in the oxidative regeneration can not occur.

With transition metals M impregnated catalysts provide another useful Type of catalyst modification. Preferred metals in addition to Nb include Ta, Ti, Mn, Zr, V, Sn, Sb, and W. It is possible the atomic ratio of the catalyst components Atomic absorption spectroscopy (AAS) to determine. The atomic ratio Si / M is 16 or more, preferably 50 or more.

Of the Main reason for this high activity of the invention Catalysts lies in the large surface of the Support materials as well as a large number of Acid centers that have a very weak to medium strength acidity exhibit. These acidic centers are good on the catalyst surface distributed. The very weakly acidic to weakly acidic centers are very favorable for the Beckmann rearrangement in the gas phase.

The results of the reaction show that, in the presence of Nb impregnated on SiO _2, higher conversions of oxime such as cyclohexanone oxime and a higher lactam such as ε-caprolactam selectivity are achieved than with other support materials. These observations could be due to the large surface and the large butt renvolumen and the low acidity can be explained.

For to become a better understanding of the present invention given some more detailed examples without this Width of the invention should be limited.

Examples

In The following Examples and Comparative Examples were as follows Materials used: cyclohexanone oxime (99.5% purity) delivery from Fluka, Germany; Ethanol (technical grade) Germany.

In these examples, the prepared catalysts were characterized by N ₂ adsorption method (BET surface area analysis) and ICP-AES (Inductively Coupled Plasma Atomic Emission Spectroscopy).

In In these examples, the reaction products and products such. Cyclohexanone, cyclohexanone oxime, ε-caprolactam and others Compounds, such. 2-cyclohexene-1-ones, 5-cyanopentane, aniline etc. identified by gas chromatography and GC / MS. sales on cyclohexanone oxime and selectivity to ε-caprolactam were calculated on the basis of GC results using Methyl undeconate calculated as internal standard.

Description of the catalysts:

Example 1: Catalyst A

Nb on a SiO _{2 support} was prepared by the impregnation method. The catalysts were synthesized according to the following method: The silica support used was DAVICAT SP 550-10021 (surface = ~ 300 m ² / g). Nb / SiO _{2 was} prepared by impregnation with NbCl ₅ . In the preparation, an appropriate amount of NbCl ₅ was first dissolved in 100 ml of isopropanol. To this solution was added 10 g of SiO ₂ support material. The resulting mixture was stirred at 110 ° C until the isopropanol had evaporated. After impregnation, the samples were dried at 110 ° C for 4 h and calcined in flowing air at 400 ° C for 4 h.

Example 2: Catalyst B

Nb on SiO ₂ -Al ₂ O ₃ support material was prepared by the same synthesis method as in Example-1. In this case, SiO ₂ -Al ₂ O ₃ (60:40) SASOL SIRAL-40 (BET area = 520 m ² / g) was used as the support material.

Example 3: Catalyst C

Nb on TiO ₂ support material was also prepared by the impregnation method as in Example-1, except that instead of SiO ₂ now TiO _{2 is used} as a carrier material. Hombicat Type II from Sachtleben was used as TiO ₂ source with a BET surface area of 107 m ² / g.

Example 4: Catalyst D

The preparation of Nb on ZrO ₂ support material is carried out analogously to Example 1. In this case, ZrO ₂ from Degussa was used.

Example 5: Description of the reactions in a fixed bed reactor

The catalytic experiments were carried out in a tubular, continuously operated fixed bed reactor with an inner diameter of 6 mm and 1 m length in the form of a spiral. The reaction zone was in a hot air oven (such as a GC oven), with which the desired temperature was adjusted uniformly over the entire reaction time. At the end of the reaction zone, a wire prevented the discharge of catalyst particles from the reactor. Cyclohexanone oxime was mixed with the solvent and any additional component in a container and fed via a Telabpumpe in the evaporator. There, the educt mixture was mixed with the N ₂ and pumped in gaseous form into the reactor.

Of the The reactor effluent was in a cryostat cooled with dry ice and isopropanol solution, collected. The collected products were analyzed by gas chromatography and the conversion and the Selectivity using an internal standard (methyl undeconate) certainly.

Examples 6-9

Examples 6-9 (Table 1) show the results obtained with the catalysts A-D after a reaction time of 4 h. Table 1: Reaction results with all catalysts: examples catalysts Temperature ° C WHSV (h ^-1 ) Weight ratio oxime: ethanol Carrier gas L / h Oxime turnover% Caprolactam selectivity% Caprolactam y. % 1 A 300 0.3 1: 9 2 98.41 95.31 93.79 2 B 300 0.3 1: 9 2 35.16 80.56 28.32 3 C 300 0.3 1: 9 2 7.24 31.74 2.29 4 D 300 0.3 1: 9 2 5.17 80.66 4.17

In comparison, the catalytic activity of pure Nb ₂ O ₅ shows 11.6 cyclohexanone oxime conversion and 82.2% caprolactam selectivity ( Surface and Coatings Technology 112 (1999) 76-79 ).

Examples 10-13

The Illustrate examples 10-13 below the present invention further.

Example 10 (see drawings, 1 ) shows the influence of the reaction temperature when using the catalyst A; under the reaction conditions WHSV = 0.3 h ^-1 , TOS = 4 h, pressure = 0.1 bar, oxime: ethanol ratio = 1: 9 wt%, carrier gas = 2 l / h N ₂ pressure 0.1 bar.

Example 11 (see drawings, 2 ) shows the regeneration cycles for Catalyst A in air atmosphere at 500 ° C for 4 h; WHSV = 0.3 h ^-1 , temperature = 300 ° C, oxime: ethanol ratio = 1: 9 wt%, carrier gas = 2 l / h N ₂ ; Pressure 0.1 bar.

Example 12 (see drawings, 3 ) shows the regeneration cycles for Catalyst A in nitrogen atmosphere at 500 ° C for 4 h; WHSV = 0.3 h ^-1 , temperature = 300 ° C, oxime: ethanol ratio = 1: 9 wt%, carrier gas = 2 l / h N ₂ ; Pressure 0.1 bar.

Example 13 (see drawings, 4 ) shows the influence of the reaction time (time on stream TOS) on conversion and selectivity in the presence of catalyst A; WHSV = 0.3 h ^-1 , pressure = 0.1 bar, temperature = 300 ° C, oxime: ethanol ratio = 1: 9 wt%, carrier gas = 2 l / h N ₂ , pressure 0.1 bar.

Example 14

Example 14 (Table-2) shows the influence of the solvent in the reaction on Catalyst A at a temperature of 300 ° C, WHSV = 0.3 hr ^-1 , oxime: solvent ratio = 1: 9 wt%, carrier gas = 2 l / h N ₂ , pressure 0.1 bar. Table 2: Influence of the solvent with catalyst A. solvent Cyclohexanone oxime conversion% Caprolactam selectivity% After 2 hours After 8 hours After 2 hours After 8 hours ethanol 97.03 93.62 96.08 88.10 methanol 98.82 90.89 98.82 95.78 benzene 73.26 68.35 92.96 93.7

Example 15

Example 15 (Table 3) shows the influence of the educt concentration in the presence of catalyst A at T = 300 ° C, WHSV 0.3 hr ^-1 , carrier gas = 2 l / hr N ₂ , pressure 0.1 bar. Table 3: Influence of the reactant stream on the reaction with catalyst A Substrate: solvent ratio (wt%) Cyclohexanone oxime conversion% Caprolactam selectivity% After 2 h After 8 h After 2 h After 8 h 1: 9 97.03 93.62 96.08 88.10 1: 6 95.54 79.94 97.55 98.28 1: 3 84.63 69.52 94.36 95.76

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• US 5618512 [0003]
• - US 4268440 [0006]
• - US 5304643 [0006]
• - JP 53-37686 A [0007]
• - JP 46-12125 A [0007]
• - GB 881927 [0007]
• GB 881956 [0007]
• US 4359421 [0007]
• - US 3016315 [0007]
• - EP 1065167 [0007]
• US 6252068 [0008]
• - JP 2-215767 A [0008]
• US 5495016 [0008]
• - JP 9-3041 A [0008]
• US 4683305 [0008]
• US 4767857 [0009]
• US 4963672 [0009]
• WO 2005/123669 (A1) [0011]
• US 6531595 [0013, 0016]
• - US 5354859 [0013]
• US 5403801 [0014]
• - EP 1028108 [0016]
• US 6265574 [0016, 0020]
• - FR 2006/001399 [0019]
• US 4968793 [0020]
• US 5741904 [0020]
• - EP 0086543 [0021]
• US 4472516 [0021]

Cited non-patent literature

• Chem. Rev., 99 (1999) 3603-3624, Cat. Today 8 (1990) 1 [0003]
• - Journal of Catalysis 260 (2008) 17 [0004]
• - Dongsen Mao et al., Journal of Molecular Catalysis A: Chemical 240 (2005) 164-171 [0007]
• - G. Heitmann et al., Applied Catalysis A: General, 185 (1999) 99-108 and J. Catalysis, 186 (1999) 12-19 [0007]
• G. Dahlhoff et al. Catal. Rev. Sci. Eng., Volume 43, no. 4 (2001) 381-441 [0007]
• G. Dahlhoff et al. (Catal. Rev. Sci. Eng., Volume 43, No. 4 (2001) 381-441 [0008]
• - W. Hölderich et al. [0008]
• - Catal Rev-Sci. Eng 43 (2001) 381 [0008]
• G. Heitmann et al., Appl. Catal, 185 (1999) 99, J.Cat, 186 (1999) 12 [0014]
• - G. Dahlhoff, et al., Studies in Surface Science and Catalysis, 139 (2001) 335-342 [0016]
• G. Heitmann et al., Journal of Catalysis 194 (2000) 122-129 [0016]
• - J. Roeseler et al. [0020]
• - J. Roeseler et al., Appl. Catal 144 (1996) 319-333 [0020]
• H. Ichihashi et al., Cat. Today 73 (2002) 23-28 [0020]
• - Surface and Coatings Technology 112 (1999) 76-79 [0070]

Claims (18)

Process for the preparation of lactams in the gas-phase or liquid-Beckmann rearrangement of the corresponding oximes, characterized in that working in the presence of Nb catalysts, wherein the Nb is applied to support materials. A method according to claim 1, characterized in that as inorganic support materials SiO ₂ , SiO ₂ -Al ₂ O ₃ , TiO ₂ , ZrO ₂ zeolites such as isomorphously substituted pentasil zeolites such as: B-MFI, TS-1, Al-MFI, mesoporous materials of MS Family such as MCM-41, MCM-48 and oxides of III. Main group elements such as Al ₂ O ₃ and B ₂ O ₃ and oxides of Lanthan group such as La ₂ O ₃ or CeO _{2 are used} with different surface, different pore size and pore distribution and different Akzidität. Method according to claim 1, characterized that in addition to Nb other transition metals such as Nb, Ta, Ti, V, Cu, Mn, Fe, Sn, Sb, W, Zr on the support material can be applied. Method according to claim 1, characterized that the application of the Nb according to common methods of Catalyst preparation z. B. i.) By dissolving a Nb salt in water, impregnating on the carrier material and Spinning off the excess water on a rotary evaporator, ii.) by impregnation according to the "incipient wetness" method iii.) by ion exchange iv.) but also by mixing the niobium compounds he follows. Method according to claim 1, characterized that the Nb at 0.1 to 30 wt .-% on the substrate is applied. Method according to claim 1, characterized that said Nb catalysts under oxidative conditions with pure oxygen or air or oxygen mixed with inert Gas such as nitrogen, methane, argon at a temperature of 200 ° C be regenerated to 600 ° C. A method according to claim 1, characterized in that the said Nb catalysts are regenerated in a non-oxidative medium such as N ₂ , argon, methane, carbon dioxide and H ₂ at temperatures of 200 to 700 ° C. Method according to claim 1, characterized that the gas phases Beckmann rearrangement in different reactor types as fixed bed reactor, fluidized bed reactor, Wibelbettreaktor with continuous regeneration, plate reactor or moving bed reactor is carried out. Method according to claim 1, characterized that the liquid phases Beckmann rearrangement in different Reactor types such as Stirred Tank Reactor, autoclaves, Cascade Reactors, Tricklebed Reactor, or Continuous Fixed Bed Reactor is carried out. Method according to claim 1, characterized that the gas phases Beckmann rearrangement in a temperature range from 250 to 500 ° C is performed. Method according to claim 1, characterized that the gas phases Beckmann rearrangement under pressure in the range of 0.01 to 10 bar is performed. Method according to claim 1, characterized that the gas phases Beckmann rearrangement at a WHSV of 0.05-15 per hour. Method according to claim 1, characterized that the liquid phases Beckmann rearrangement in a temperature range from 20 to 200 ° C is performed. Method according to claim 1, characterized that the liquid phases Beckmann rearrangement under pressure in the range of 0.5 to 10 bar is performed. Method according to claim 1, characterized that the liquid phases Beckmann rearrangement during a loading from 2 g of oxime per 1 g of catalyst to 100 g of oxime per 1 g of catalyst is carried out. A method according to claim 1, characterized in that the Beckmann rearrangement in an inert medium preferably, nitrogen and / or hydrogen and / or argon and / or CH ₄ and / or CO ₂ be performed. Method according to claim 1, characterized that the Beckmann rearrangement in the presence of polar and not polar solvents such as methanol, ethanol, benzene, cyclohexanol, Isopropanol, toluene and xylene are carried out. Method according to claim 1, characterized that the weight ratio of substrate to solvent is set in the range of 1: 1 to 1:15.