JP2001335561A - Method for producing lactam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a lactam from a cyclic ketone with high selectivity. SOLUTION: This method for producing the lactam by reacting the cyclic ketone with a nitrogen source and oxygen in the presence of an oxide catalyst is characterized as the reaction is carried out under the condition with a composition ratio regulated so as to be 0.01-10 mol nitrogen source and 0.1-5 mol oxygen based on 1 mol cyclic ketone.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a lactam directly from a cyclic ketone, a nitrogen source and oxygen. Among lactams, ε-caprolactam is an industrially important compound as a raw material for 6-nylon.

[0002]

2. Description of the Related Art Several processes for producing ε-caprolactam are known, but the most widely used industrial process is to react cyclohexanone with hydroxylamine to form cyclohexanone oxime, which is then subjected to Beckmann rearrangement with sulfuric acid. This is a method of making ε-caprolactam.
Hydroxylamine is produced by oxidizing ammonia to form nitric oxide (NO), which is then reduced. This method requires a long process and requires sulfuric acid in the hydroxylamine production process and the Beckmann rearrangement process, and since this sulfuric acid is finally neutralized with ammonia to ammonium sulfate, a large amount of ammonium sulfate is discharged. There is a problem. Therefore, many efforts have hitherto been made for a new method for producing ε-caprolactam. For example, JP-A-62-59256 and JP-A-63-59256
JP-A-130575 describes that cyclohexanone, ammonia and hydrogen peroxide are reacted in the liquid phase in the presence of a zeolite TS-1 having an MFI-type structure containing titanium to produce cyclohexanone oxime.

Also, US Pat. No. 4,163,756,
J. cat. , 70 (1981), p72-83, p8
4-91, J.M. cat. , 72 (1981) p66-7.
4, 73 (1982) pp. 57-65, J. Am. Amer. C
hem. Soc. , 102 (1980) p1453 and Catalysis Letters, 11 (199).
1), pages 285 to 294, describe that a gas containing cyclohexanone, ammonia and oxygen is brought into contact with silica or a catalyst mainly composed of silica to produce cyclohexanone oxime.

JP-A-62-123167 and JP-A-63-54358 disclose that cyclohexanone oxime is subjected to Beckmann rearrangement in the gas phase using an MFI-type zeolite containing substantially no aluminum as a catalyst to obtain ε-.
The production of caprolactam is described, but the reaction is carried out at a high reaction temperature of 350 ° C. On the other hand, a method for producing ε-caprolactam from cyclohexanone is described in J. Am. N. Armor, J.A. Cat
l. 70 (1981) p72. Describes a method for producing ε-caprolactam by reacting cyclohexanone with ammonia and an oxidizing agent in a two-stage reactor using an alumina-silica catalyst, and is described in U.S. Pat. No. 4,163,163.
756 describes a method for producing ε-caprolactam from cyclohexanone using two types of catalysts, γ-alumina and La-molecular sieve, in a two-step reaction zone. In addition, R. Prasad et a
1, J .; Cat. 161 (1996) 373 describes a method for producing ε-caprolactam by reacting cyclohexanone with ammonia and nitric oxide in a liquid phase using an alumina-silica catalyst.

Regarding the ratio of ammonia to cyclohexone in the prior art, see US Pat. No. 4,163,163.
No. 756 and U.S. Pat. No. 4,225,551 describe "preferably using excess ammonia". Also, most prior art uses an excess ammonia ratio relative to cyclohexanone.

[0006]

As described above, several improvements have been proposed for the process for producing ε-caprolactam.However, in the prior art, cyclohexanone oxime was produced from cyclohexanone, and then ε-caprolactam was obtained from the obtained cyclohexanone oxime. -A method of producing caprolactam, or a method of producing ε-caprolactam from cyclohexanone in a two-stage reactor, in order to obtain a lactam, it is only a multi-step process, and it costs construction costs and variable costs. There was a problem.
Further, as described above, a method of producing ε-caprolactam in one step from cyclohexanone in one reactor,
R. Prasad et al, J. Mol. Cat. 161
(1996) pp. 373, but according to additional tests by the present inventors, it was found that ε-caprolactam was hardly produced, and reproducibility was not obtained.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies in view of the above-mentioned problems, and as a result, by setting a specific ratio of a nitrogen source and oxygen to a cyclic ketone, the reaction with the prior art has been improved. The present inventors have found that a method for producing lactams in a single step and with high selectivity in a single reactor from cyclic ketones having different contents can be realized, and arrived at the present invention.
That is, the gist of the present invention is to provide a method for producing a lactam by reacting a cyclic ketone with a nitrogen source and oxygen in the presence of an oxide catalyst, wherein the nitrogen source is added in an amount of 0.1 mol per mol of the cyclic ketone.
A method for producing a lactam, characterized in that the reaction is carried out under a condition that the composition ratio of oxygen is from 0.1 to 10 mol and oxygen is from 0.1 to 5 mol.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The present invention provides a method for producing a lactam by reacting a cyclic ketone with a nitrogen source and oxygen in the presence of an oxide catalyst to control the ratio of the nitrogen source to the cyclic ketone and oxygen in a specific range, thereby converting the lactam to a specific range. It is characterized in that it can be produced in one step, and that the lactam can be obtained at a high selectivity and the catalyst life is improved.

The cyclic ketone as a raw material of the present invention is not particularly limited as long as it is a ketone having a cyclic structure, but is usually a cyclic ketone having 3 to 15 carbon atoms and has a condensed ring or a heterocyclic structure. You may. Among them, cyclic ketones having 4 to 7 carbon atoms such as cyclopentanone, cyclohexanone, and cycloheptanone are preferable, and it is particularly preferable to use cyclohexanone. When cyclohexanone is used, the resulting lactam is ε-caprolactam.

It is not clear why the molar ratio of the nitrogen source and oxygen to the cyclic ketone as the substrate is important in the present invention, but the conversion of the cyclic ketone increases when a large excess of the nitrogen source is used. However, the selectivity of lactam is low, and it is considered that the reaction between imines, which are produced intermediates, the reaction between imine and cyclic ketone, and the formation of polymer are easily advanced, which is disadvantageous for lactam production. In addition, when oxygen is excessive, not only the burning of the substrate and the formation of a polymer containing an N-containing compound progresses, but also the selectivity of the lactam decreases, and the burning of the nitrogen source progresses, and the lactam selectivity based on the nitrogen source is increased. Is disadvantageous. From these factors, it is important to control side reactions in order to produce lactam efficiently.
To that end, he speculates that it is necessary to optimize the ratio of the nitrogen source and oxygen to the substrate.

The specific ratio of the nitrogen source and oxygen in the present invention is a ratio supplied to the reactor, and is a molar ratio when the cyclic ketone is 1 mole, and is expressed as cyclic ketone: nitrogen source: oxygen =
1: 0.01-10: 0.1-5, preferably 1: 0.01-10: 0.1-3.5, more preferably 1: 0.01-5: 0.1-3. And more preferably 1:
0.01-2.5: 0.1-3, most preferably 1:
The range of 0.01 to 2.5: 0.1 to 1.5 is selected. The molar ratio between the oxygen and nitrogen sources is preferably 1.9 or less. Here, the number of moles of the nitrogen source is calculated as the number of moles of N. The reaction can be performed in a liquid phase or a gas phase, but is usually performed in a gas phase.

The nitrogen source in the present invention is a solid, liquid or gaseous compound having an NH ₂ atomic group at room temperature and normal pressure, and is not particularly limited. Specific examples thereof include ammonia, inorganic ammonium salts, and carboxylic acids. And the like, amines, urea and the like. These NH ₂
Among the atomic group-containing compounds, compounds that can generate CO _{2 in the} reaction system are preferable, and urea and ammonia are more preferable. The method of supplying these NH ₂ group-containing compounds is as follows: in the case of a gas, the substance is melted at a temperature equal to or higher than its melting point in the case of a solid, and may be supplied to a reactor or dissolved in a solvent such as water. May be supplied as an aqueous solution.
When the catalyst moves, such as in a fluidized bed or a moving bed, a method of mixing these substances with the catalyst and supplying it to the reactor may be used.

The cyclic ketone may be supplied alone or, if necessary, diluted with an inert gas, an organic compound such as benzene, or water. If the concentration of the cyclic ketone is too low, the reaction efficiency is poor, and if it is too high, the reaction temperature increases,
The desired lactam selectivity and catalyst life tend to be reduced. Therefore, in the present invention, the concentration of the cyclic ketone in the whole feed gas is 0.01 to 50 mol%, preferably 0.01 to 30 mol%, more preferably 0.1 to 30 mol%.
-20 mol%. The space velocity of the cyclic ketone is 0.001 to 100 hr ^-1 as WHSV (that is, the supply rate of the cyclic ketone per kg of the catalyst is 0.001 to 100 kg per hour), preferably 0.01 to 5 hr.
0 hr ^-1 , more preferably 0.01 to 20 hr ^-1 .

The method for supplying the cyclic ketone and gas used in the reaction may be such that the cyclic ketone, nitrogen source, oxygen, inert gas, and diluent for the organic compound are separately supplied to the catalyst layer.
You may supply after mixing more than a kind. Further, the cyclic ketone serving as the substrate may be supplied after being vaporized, or may be vaporized in the reaction system. In any case, it is preferable to supply the components in a reaction system in which the catalyst is present such that the respective components are in a well-mixed state. Since a mixed gas of cyclic ketone, decomposition product of nitrogen source, oxygen, and diluent of organic compound may show explosive property, it is usually diluted with an inert gas such as nitrogen, carbon dioxide, argon, etc. for the reaction. Is preferred. Among them, it is more preferable to use carbon dioxide. Since carbon dioxide reacts with ammonia to produce ammonium carbamate, it is desirable that the piping of the supplied gas be kept at 50 ° C. or higher in a region where these gases are mixed.

The oxide catalyst used in the present invention is not particularly limited, but is preferably an oxide catalyst containing at least one element M selected from Groups 3 to 12 of the periodic table, Further, an oxide catalyst containing silicon is preferable. Here, the “element M” includes not only a single element but also a plurality of elements. It is preferable that at least one element M selected from Group 3 to Group 12 of the periodic table contains at least one element selected from Group 4 to Group 8 of the periodic table. Further, when one or more elements M selected from Groups 3 to 12 of the periodic table include a plurality of elements, each is an element selected from Groups 4 to 8 of the periodic table. Is preferred.
Further, elements selected from Groups 4 to 8 of the periodic table include titanium (Ti), niobium (Nb), and tantalum (T
a), at least one selected from hafnium (Hf), zirconium (Zr) and tungsten (W), and further, titanium (Ti), niobium (Nb),
Zirconium (Zr) and tungsten (W) are preferred, and titanium is particularly preferred because it has a high selectivity for ε-caprolactam produced by a reaction catalyzed by an oxide catalyst containing these.

The oxide catalyst may be amorphous or crystalline, but is preferably a crystalline oxide, and more preferably a composite oxide, particularly zeolite. In addition,
In the case of a crystalline oxide, the element M of Group 3 to Group 12 may be present in the lattice or outside the lattice. The crystalline oxide referred to here is an oxide composed of crystalline, and the composite oxide refers to an oxide in which two or more metal components coexist. Further, the crystalline oxide does not include a mesoporous substance.

The oxide catalyst of the present invention is a catalyst having a small acid content, for example, a catalyst society of Japa
It is preferable that the catalyst has an acid amount equal to or less than that of alumina (JRC-ALO-4) as the reference catalyst of n). The amount of acid can be determined, for example, by temperature programmed desorption analysis of ammonia. Also, from the viewpoint of acid strength, a weak catalyst is preferable. The acid strength can also be evaluated by temperature-programmed desorption analysis of ammonia, but can be more simply measured with, for example, a Hammett indicator. The oxide catalyst of the present invention has a thermal desorption analysis of ammonia (TP
It is preferable that the amount of ammonia desorbed by D: temperature programmed desortion is equal to or less than that of alumina (JAC-ALO-4). In particular,
It is preferable that the catalyst has a small amount of acid such that the amount becomes 0.5 mmol-NH3 / g-cat or less, and more preferably 0.3 mmol-NH3 / g-cat.
Hereinafter, a catalyst having a concentration of 0.1 mmol-NH3 / g-cat or less is particularly preferable. In addition, "mmol-NH3 / g-cat" represents the amount of ammonia desorbed (mmol) per 1 g of the oxide catalyst.

Regarding the acid strength, Hammet (Hamm
ett) When represented by an acidity function H ₀ measured with an indicator, the acidity function H ₀ is a catalyst that is usually larger than −3.0, preferably a catalyst larger than +1.5, and more preferably a catalyst larger than +1.5.
Catalysts greater than +3.3, especially catalysts greater than +4.0 are preferred. The amount of ammonia desorbed by the temperature-programmed desorption analysis is as follows.After ammonia is saturated and adsorbed on the catalyst at a predetermined temperature, ammonia that is weakly bound to the catalyst and ammonia in the atmosphere are removed by degassing or the like. Is measured by quantifying the amount of ammonia desorbed from the catalyst by increasing This value is typically measured in the present invention under the following conditions. <Measuring device> Measuring device: Automatic thermal desorption spectrometer (TP-5000) manufactured by Okura Riken Co., Ltd. 5000) Specifications ”. The outline of the apparatus is shown in FIG. 1, and the reaction tube used is shown in FIG.

[0019]

[Table 1] <Measurement conditions> Carrier gas (helium): Helium gas manufactured by Union Helium Ammonia: liquid ammonia manufactured by Showa Denko (purity 99.9% or more) (Carrier gas and ammonia were used without purification, etc.) Measurement Amount of catalyst used for the measurement: 200 mg Reaction tube used for measurement: The reaction tube shown in FIG. 2 was used. The measurement was performed by the automatic control / measurement program of TP-5000.

[0020]

[Table 2] <Measurement procedure> (1) Pretreatment The temperature was raised to 470 ° C (internal temperature 500 ° C) in 45 minutes at a pressure of 1 torr or less, and then maintained at 470 ° C for 30 minutes. (2) NH ₃ pulse adsorption Setting 100 ° C (Internal temperature 110 ° C) End time of one pulse: 3 minutes Volume of NH ₃ pulse (measuring tube): 0.953cc (0 ° C, 1 atm conversion) Carrier gas (helium) pressure: 0.05MPa

[0021]

[Table 3] (Setting conditions of NH ₃ pulse) Pulse end condition: Non-adsorbed NH ₃ amount in three pulses from the last pulse falls within an error range of ± 3%. Maximum number of pulses: 10 times If the number of pulses does not reach the condition specified in the pulse end condition and the pulse is not reached, the process ends with this number of times. Minimum number of pulses: 4 Irrespective of the pulse end condition, at least this number of pulses are injected.

The maximum He purge time after the NH ₃ pulse (TCD
Waiting time for stabilization): 2 minutes Time to introduce pulse gas into piping: 30 seconds Time until atmospheric pressure in measuring tube: 20 seconds Time to detect one peak of pulse: 360 seconds (3) Purging , deaeration treatment (vacuum degassing, 100 ° C., 30 minutes) (4) TCD (thermal conductivity detector) stability check (100 ° C.) (5) 100 to 800 ° C. in NH ₃ temperature programmed desorption 10 ° C. / min The temperature was raised and the temperature was kept at 800 ° C. for 20 minutes. Carrier gas flow rate 30 ml / min (6) Standard pulse measurement (NH ₃ pulse supplied without passing through a reaction tube containing a catalyst is referred to as a standard pulse (NH ₃ pulse volume 0.953 cc; 0 ° C./atm) This area is measured, and the desorbed amount of ammonia is converted based on this area.)

Detector: TCD detector (set current 3) and mass spectrometer line piping (dotted line in FIG. 2) and constant temperature bath at 100 ° C.
Kept warm. (All piping is 1/8 inch except for the purge section (the thick line in FIG. 2: 1/4 inch)) A heat insulating material was attached to the upper surface of the reaction tube. Electric furnace control: Auto chewing implemented

After the completion of the NH ₃ pulse, NH ₃ thermal desorption ((5))
The time required for purging, degassing ((3)) and TCD stability confirmation ((4)) until the start of the process is about 43 minutes. The acquired data is analyzed using the waveform editing / analysis program analysis software (model MPS-880 waveform editing program) manufactured by Okura Riken Co., Ltd., and the thermal conductivity is detected by analyzing the waveform of each peak and calculating the area. The desorbed amount of ammonia was determined from the area ratio of the standard pulse of the vessel (TCD) to the desorbed ammonia. In addition, when alumina (JRC-ALO-4) as a reference catalyst of the Catalysis Society of Japan was measured under the same conditions, the amount of released ammonia was 0.11 to 0.36 mmol-NH ₃ / g-cat.

The oxide catalyst of the present invention preferably has an aluminum content of 1% by weight or less, more preferably 0.5 wt.
t% or less, particularly 0.1 wt% or less, most preferably 0.05 wt% or less is preferable in that the selectivity of ε-caprolactam to be formed is improved. Also,
The total concentration of the element M in the oxide is usually at least 0.01 mol%, preferably at least 0.2 mol%, particularly preferably at least 0.5 mol%.
It is preferably at least 1 mol%. When the oxide catalyst of the present invention contains silicon, the ratio of the number of silicon atoms to the total number of atoms of the element M in the oxide catalyst (Si / M) is 20 or more, further 30 or more, particularly 50 or more. Preferably, there is. If this atomic ratio is too small, the selectivity of lactam and by-product oxime generally decreases. If the atomic ratio is too large, the catalytic action of the element M is hardly exhibited. Therefore, this atomic ratio (Si / M) is usually 10 to 200, preferably 20 to 190, particularly preferably 50 to 190.
It is preferable to use 150. Although the oxide catalyst of the present invention acts alone as a catalyst, a plurality of types of oxide catalysts may be used as a mixture. Among them, in the present invention, it is preferable to use a single catalyst.

As a method for synthesizing the oxide catalyst of the present invention, in the case of a crystalline composite oxide containing both one or more elements M selected from Groups 3 to 12 and silicon, for example, From the compound of the element M and the silicon compound by a known zeolite synthesis method. For example, a material obtained by a method of performing a hydrothermal synthesis treatment on a silica raw material and a raw material for the component of the element M in the presence of a tetrapropylammonium salt as a mold material in the presence of an alkali can be used. Alternatively, a material obtained by removing aluminum from an MFI-type zeolite containing aluminum by an acid treatment or the like, and then introducing an element M of Group 3 to Group 12 into the position where aluminum is desorbed can be used.

The raw material of one or more components of the element M selected from Groups 3 to 12 of the periodic table is not particularly limited, but salts of these metals, for example, nitrates, sulfates, acetic acids Halides such as salts, oxalates, carbonates, chlorides and bromides, or metal alkoxides can be used. Among them, metal alkoxides, nitrates, acetates, and oxalates are preferred. When preparing a silicon-containing composite oxide, the raw material of silicon is not particularly limited, but commercially available silica, tetraalkyl orthosilicate,
Aerosil, colloidal silica, sodium silicate and the like can be mentioned. Alternatively, for example, a preformed silica carrier is impregnated with a solution containing a compound of the element M selected from Groups 3 to 12 of the periodic table, and then subjected to thermal decomposition, hydrolysis, and subsequent thermal decomposition. Alternatively, a silica-supported catalyst prepared by changing the compound of the impregnated element to an oxide can also be used.

The atmosphere for the thermal decomposition in preparing the catalyst may or may not contain oxygen. In an atmosphere containing oxygen, if there is an oxidizable substance such as an organic substance, local heat generation is observed due to its oxidation and combustion, which may inhibit the reactivity of the obtained catalyst. Better to do. The temperature of the thermal decomposition is 400 ° C. or higher, but the condensation reaction of cyclohexanone, etc., which occurs as a side reaction, also occurs depending on the acid properties of the carrier. Therefore, it is more preferable to treat at a temperature of 500 ° C. or higher.

In the present invention, when urea is used as a nitrogen source, water must be present in the reaction system in order to hydrolyze the urea. Need not be added. The presence of water in the reaction system can improve the lactam selectivity. In this case, the amount of water is usually 0.001 to 10 per mol of the cyclic ketone as the substrate.
It can be appropriately selected within the range of 00 mol, preferably 0.01 to 500 mol, and more preferably 0.1 to 100 mol. When water is added, it is necessary to adjust the reaction temperature or the amount of catalyst in accordance with the conversion of the cyclic ketone.

The reaction temperature is usually from 150 to 400 ° C., but the present invention has an advantage that lactams can be produced with high selectivity even at a temperature of 150 to 320 ° C., which is relatively lower than the conventional Beckmann transition reaction temperature. . The reaction pressure may be normal pressure or slight pressure. Further, according to the present invention, a lactam can be produced with a high selectivity in a single reaction zone without using a conventionally known multistage reactor.

As the reaction apparatus, a conventional fixed-bed reactor or fluidized-bed reactor can be used. When carbonaceous matter generated by a side reaction accumulates on the catalyst and reduces the catalytic activity, use of a fluidized bed reactor is necessary in terms of easy extraction and replenishment of the catalyst and easy control of the reaction temperature. Is preferred. The activity of the catalyst with reduced activity can be recovered by removing the deposited carbonaceous material by an appropriate method such as washing or burning.

The method of recovering the product after the reaction will be described below, taking as an example the case of producing ε-caprolactam from cyclohexanone. From the reaction product gas flowing out of the reactor, ε-caprolactam generated by appropriate means such as cooling or solvent absorption can be recovered. Since unreacted cyclohexanone and by-product cyclohexanone oxime are usually contained in the reaction product gas, ε-caprolactam coexists with these unreacted products and by-products during cooling and solvent absorption. Since a solution is obtained, ε-caprolactam, cyclohexanone oxime and cyclohexanone are separated and recovered from the solution by an appropriate means such as distillation or crystallization. The recovered cyclohexanone is reused in the reaction, and cyclohexanone oxime is obtained by a known method.
Can be converted to caprolactam. Alternatively, as another method, J. Cat. , 70 (1981) according to the method described in
The cyclohexanone oxime contained can also be converted into ε-caprolactam by subsequent contact with a gas phase Beckmann rearrangement catalyst.

[0033]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. The preparation of the catalyst described below was carried out with sufficient stirring. (Preparation of catalyst) 40% by weight aqueous solution of tetrafluoroammonium human peroxide
To 46.98 g, 55.56 g of tetraethoxysilane was added dropwise with vigorous stirring, and the resulting reaction solution was continuously stirred for 45 minutes. The此of the reaction solution, adding a solution prepared by dissolving 0.75g of Tetorafu Bu Tokishichitan the _{(Ti- (n-OC 4 H} 9) 4) in isophthalic ° Loja ° Nord 18 g, was subsequently stirred for 1 hour. While further stirring vigorously, 114.37 g of demineralized water was added thereto, and the mixture was further stirred for 30 minutes. The solution was clear and colorless.

The solution was subjected to hydrothermal synthesis using a hydrothermal synthesis reactor KH-03SA manufactured by Hiro Co., Ltd. The micro-autoclave used was a 200 cc one equipped with a Teflon (registered trademark) inner cylinder dedicated to the same apparatus. The solution in the micro autoclave was stirred at a rotation speed of the rotation shaft of 15 rpm. Oven temperature is 183 ° C for 1 hour
And maintained this state for 72 hours. After hydrothermal synthesis, the obtained slurry was filtered and washed with water to obtain a white solid, which was dried at 120 ° C. for one day and night, and then heated to 550 ° C. while controlling heat generation under an air atmosphere. 55
It was calcined at 0 ° C. for 8 hours to obtain a catalyst. This is powder X
As a result of X-ray diffraction, it was identified as crystalline composite oxide ZSM-5, Si / Ti = 120, and the amount of desorbed ammonia was 0.01.
It was mmol-NH ₃ / g · cat.

Example 1 A length of 32 cm, an inner diameter of a central portion of 6 mm, a length of 4.5 cm,
The quartz glass tube type reaction tube with an inner diameter of 4 mm
1 ml of the above catalyst (0.46
g) and preheated at 260 ° C. for 1 hour. Next, a mixed gas of ammonia, cyclohexanone, air, and nitrogen was supplied under the conditions shown in the table, and supplied and reacted under the conditions shown in the table. The gas flowing out of the reaction tube was condensed by cooling on ice, and the condensate was analyzed by gas chromatography. When water was separated, the same analysis was performed on the aqueous phase as needed. As a column, 5% PEG-HT / Unip
An ort HP (60/80 mesh) 3 m glass column was used, and cyclopentanone was used as an internal standard.
The results are shown in the table.

Examples 2 to 5 and Comparative Examples 1 and 2 The reaction was carried out in the same manner as in Example 1 except that the composition of the reaction gas was supplied under the conditions shown in the table. The results are shown in the table.

Cyclohexanone (CHN) conversion, caprolactam (CL) selectivity, and cyclohexanone oxime (OXM) selectivity were determined as follows.

## EQU1 ## CHN conversion (%) = ｛(mol number of CHN supplied−
Recovered CHN moles / (CHN moles supplied) モ ル × 100 CL, OXM selectivity (%) = (moles of CL or OXM produced / moles of converted CHN) × 100

[0038]

[Table 4]

As is clear from the table, in Comparative Example 1, the activity was high but the selectivity was low, which is considered to be due to an increase in side reactions. In Comparative Example 2, the activity and the selectivity of CL were greatly reduced with the elapse of the reaction time, and the catalyst life was short. On the other hand, in the example, although a lower conversion rate than the comparative example, a higher selectivity was obtained,
According to the method of the present invention, a high selectivity can be maintained by employing a method of recycling unreacted cyclic ketone, and thus a high-quality lactam can be obtained.
Also, the catalyst life is improved.

[0040]

According to the present invention, by setting a specific nitrogen source and oxygen ratio, a lactam can be produced from a cyclic ketone with a high selectivity, and can be produced in one step. Since the catalyst life is long, it has high industrial utility value.

[Brief description of the drawings]

[Figure 1] Automatic thermal desorption spectrometer (Okura Riken Co., Ltd. TP-500
It is a figure showing the outline of 0).

FIG. 2 is a view showing the structure of a reaction tube used for thermal desorption analysis by an automatic thermal desorption analyzer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reaction tube 2 Electric furnace 3 Temperature indicator 4 Mass spectrometer 5 Oil rotary vacuum pump 6 Constant temperature bath 7 Solenoid valve 7 '6-way solenoid valve 7 "4-way solenoid valve 8 Thermal conductivity detector (sample side) 9 Heat conduction Degree detector (reference side) 10 Thermocouple insertion port 11 Pressure reducing valve

Continuation of the front page (72) Inventor Toru Setoyama 1000 Kamoshita-cho, Aoba-ku, Yokohama-shi, Yokohama-shi F-term in Mitsubishi Chemical Corporation Yokohama Research Laboratory 4C034 DE03 4H039 CA42 CH90

Claims (12)

[Claims] 1. A method for producing a lactam by reacting a cyclic ketone with a nitrogen source and oxygen in the presence of an oxide catalyst, wherein the nitrogen source is present in an amount of 0.01 to 1 per mole of the cyclic ketone.
A method for producing a lactam, characterized in that the reaction is carried out under a condition that a composition ratio of 0 mol and oxygen is 0.1 to 5 mol. 2. The method for producing a lactam according to claim 1, wherein the composition ratio of the nitrogen source is 0.01 to 2.5 and oxygen is 0.1 to 1.5 per mole of the cyclic ketone. 3. The method for producing a lactam according to claim 1, wherein the lactam is produced by reacting a cyclic ketone with a nitrogen source and oxygen using a single reactor. 4. The method for producing a lactam according to claim 1, wherein the reaction is performed in a gas phase. 5. The method for producing a lactam according to claim 1, wherein the oxide catalyst is an oxide catalyst containing at least one element selected from Groups 3 to 12 of the periodic table. 6. The lactam according to claim 1, wherein the reaction is carried out in the presence of an oxide catalyst containing at least one element selected from Groups 3 to 12 of the periodic table and silicon. Production method. 7. The method for producing a lactam according to claim 6, wherein an oxide catalyst having a ratio of the number of silicon atoms to the total number of atoms of elements selected from Groups 3 to 12 of the periodic table is 20 to 190. 8. The method for producing a lactam according to claim 1, wherein an oxide catalyst having an amount of desorbed ammonia by thermal desorption analysis of ammonia of 0.5 mmol-NH3 / g-cat or less is used. . 9. An oxide catalyst having an aluminum content of 1
The method for producing a lactam according to any one of claims 1 to 8, which is not more than wt%. 10. The method for producing a lactam according to claim 1, wherein the reaction is carried out at 150 to 320 ° C. 11. The method according to claim 1, wherein the reaction product gas containing the lactam produced by the reaction is cooled or absorbed by a solvent to obtain a lactam-containing solution, and the lactam is recovered therefrom. Lactam production method. 12. The method according to claim 1, wherein the cyclic ketone is cyclohexanone and the lactam is ε-caprolactam.
2. The method for producing a lactam according to any one of 1.