KR20140090605A - PRODUCTION METHOD FOR ε-CAPROLACTAM - Google Patents

Abstract

The present invention relates to a process for producing a cyclohexanone oxime by converting a cyclohexanone oxime into ε-caprolactam by performing a gas phase reaction in which cyclohexanone oxime is brought into contact with a solid catalyst in the coexistence of a lower alcohol and by controlling the amount of water, ammonia and amines (1) to (3), wherein the lower alcohol is a product of the production of? -Caprolactam containing the recovered lower alcohol recovered from the reaction mixture obtained in the gas phase reaction ≪ / RTI >
(1) 0? {[Ammonia (moles) / lower alcohol (moles)] x 100} < 14
(2) 0 < {[water (moles) / lower alcohol (moles)] x 100} &lt; 11
(3) 0? {[Amines (Mols) / Lower Alcohol (Mols))] × 100} <7.5

Description

PRODUCTION METHOD FOR ε-CAPROLACTAM}

The present invention relates to a process for producing ε-caprolactam which produces ε-caprolactam from cyclohexanone oxime by a gas phase reaction using a solid catalyst.

The present application claims priority based on Japanese Patent Application No. 2011-228142 filed on October 17, 2011, the contents of which are incorporated herein by reference.

? -caprolactam is an important periodic chemical raw material which becomes a raw material for nylon and the like, and as a production method thereof, there is known a process having a step of performing a dislocation reaction (Beckmann dislocation) of cyclohexanone oxime in a gas phase reaction using a solid catalyst. A method of improving the reaction rate of cyclohexanone oxime, the selectivity of? -Caprolactam and the catalyst life by performing a dislocation reaction in the presence of a lower alcohol has been disclosed (see Patent Document 1). According to this method, 竜 -caprolactam is obtained at an extremely high selectivity even under the condition that the reaction rate of cyclohexanone oxime is substantially 100%, and the lifetime of the catalyst is remarkably improved.

Japanese Patent No. 2616088

In the production method described in Patent Document 1, the lower alcohol used in the dislocation reaction can be recovered and reused after the reaction, which is an important step in the production of? -Caprolactam at low cost.

On the other hand, in order to improve the yield of? -Caprolactam, it is important to reduce the amount of impurities incorporated in the dislocation reaction to improve the reaction rate and selectivity. For example, a lower alcohol that is recovered and reused can be one of the main factors of impurity incorporation into the reaction system. Therefore, it is necessary to reduce such impurities. Thus, by reducing the amount of impurities,? -Caprolactam can improve the new yield.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a process for producing ε-caprolactam, which is excellent in the reaction rate and selectivity in the dislocation reaction of cyclohexanone oxime.

In order to solve the above problems, the present invention provides a process for producing ε-caprolactam from cyclohexanone oxime by gas phase reaction using a solid catalyst in the presence of a lower alcohol, And a lower alcohol recovered from the reaction mixture of the gas phase reaction, wherein the amount of water, ammonia and amines in the gas phase reaction is controlled to the following values.

(1) 0? {[Ammonia (moles) / lower alcohol (moles)] x 100} < 14

(2) 0 < {[water (moles) / lower alcohol (moles)] x 100} < 11

(3) 0? {[Amines (Mols) / Lower Alcohol (Mols))] × 100} <7.5

In the process for producing epsilon -caprolactam of the present invention, the gas obtained by distilling and separating a gas containing a lower alcohol as a main component from the reaction mixture and cooling and condensing the gas is further distilled to obtain a recovered lower alcohol At least in part.

In the process for producing [epsilon] -caprolactam of the present invention, it is preferable that the solid catalyst is zeolite.

According to the present invention, it is possible to provide a process for producing ε-caprolactam which is excellent in the reaction rate and selectivity in the dislocation reaction of cyclohexanone oxime.

In addition, by reusing the recovered lower alcohol, the amount of industrial waste can be reduced, and the burden on the environment can be reduced.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a flow chart showing a manufacturing process in a process for producing? -Caprolactam according to an embodiment of the present invention; FIG.

The process for producing [epsilon] -caprolactam according to the present invention is a process for producing [epsilon] -caprolactam which generates [epsilon] -caprolactam from cyclohexanone oxime by a gas phase reaction using a solid catalyst in the presence of a lower alcohol. (Hereinafter sometimes referred to as &quot; recovered lower alcohol &quot;) recovered in the reaction mixture of the above-mentioned vapor phase reaction as the coexisting lower alcohol, wherein the amount of water, ammonia and amines in the vapor phase reaction is And the value is adjusted to a value.

(1) 0? {[Ammonia (moles) / lower alcohol (moles)] x 100} (hereinafter sometimes referred to as "mole percentage (a)") <14

(2) 0 <{[water (number of moles) / lower alcohol (mole number)] × 100} (hereinafter sometimes referred to as "mole percentage (b)") <11

(3) 0? {[Amines (mols) / lower alcohol (mols)] x 100} (hereinafter sometimes referred to as "mole percentage (c)") <7.5

In the gas phase reaction, the dislocation (Beckmann dislocation) reaction of cyclohexanone oxime proceeds.

That is, the present invention relates to the following.

[1] A method for purifying a cyclohexanone oxime by converting a cyclohexanone oxime into ε-caprolactam by performing a gas phase reaction in which cyclohexanone oxime is brought into contact with a solid catalyst in the coexistence of a lower alcohol and a method of converting the amount of water, ammonia and amines (1) to (3), wherein the lower alcohol is a mixture of ε-caprolactam recovered from the reaction mixture obtained in the gas phase reaction and a recovered lower alcohol Gt;

(1) 0? {[Ammonia (moles) / lower alcohol (moles)] x 100} < 14

(2) 0 < {[water (moles) / lower alcohol (moles)] x 100} < 11

(3) 0? {[Amines (Mols) / Lower Alcohol (Mols))] × 100} <7.5

[2] The process for producing ε-caprolactam according to [1], wherein the recovered lower alcohol comprises a distilled lower alcohol and the distilled lower alcohol is obtained by the following method, Separating the gas containing the lower alcohol as a main component, cooling a part of the gas by cooling to obtain a liquid mixture containing the lower alcohol as a main component, further distilling the liquid mixture to obtain a distilled lower alcohol .

[3] The process for producing ε-caprolactam according to [1] or [2], wherein the solid catalyst is a zeolite.

[4] a vaporization step of evaporating the cyclohexanone oxime under the coexistence of an inert gas and a lower alcohol to obtain a source gas containing cyclohexanone oxime, an inert gas and a lower alcohol, a vapor phase reaction in which the source gas is contacted with the solid catalyst To convert the cyclohexanone oxime into? -Caprolactam to obtain a reaction gas containing? -Caprolactam, a lower alcohol and an inert gas, a step of cooling the reaction gas, A first distillation step of separating a high boiling point component as an impurity and obtaining a mixed gas containing? -Caprolactam, a lower alcohol and an inert gas, a step of separating a mixed low-alcohol containing a lower alcohol and an inert gas, A low-alcohol separation step of separating a crude? -Caprolactam mixture containing caprolactam, A second distillation step of separating a low boiling point component and a high boiling point component as an impurity from the lactam mixture to obtain? -Caprolactam, and a lower alcohol recovery step of recovering a recovered lower alcohol by purifying a part or the whole amount of the prepared lower alcohol Wherein the method for preparing? -Caprolactam further comprises adjusting the amounts of water, ammonia and amines coexisting in the gaseous reaction system to the values of the following (1) to (3): ,? -caprolactam.

(1) 0? {[Ammonia (moles) / lower alcohol (moles)] x 100} < 14

(2) 0 < {[water (moles) / lower alcohol (moles)] x 100} < 11

(3) 0? {[Amines (Mols) / Lower Alcohol (Mols))] × 100} <7.5

[5] The process for producing ε-caprolactam according to [4], wherein the solid catalyst is zeolite.

Hereinafter, a method for producing [epsilon] -caprolactam according to the present invention will be described with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a flow chart showing a manufacturing process in a process for producing? -Caprolactam according to an embodiment of the present invention; FIG.

This embodiment relates to a vapor phase process (1) in which a cyclohexanone oxime (7) is evaporated under the coexistence of an inert gas (8), a lower alcohol (9) and water (10), a cyclohexanone oxime 7) is subjected to beckone dislocation reaction, the reaction gas 12 is cooled, the high boiling point component 13 is separated from the reaction solution, and a mixture of? -Caprolactam, a lower alcohol and an inert gas A first distillation step (3) for obtaining a gas (14), a lower alcohol and an inert gas are separated from the mixed gas (14), and the prepared lower alcohol (15) containing an inert gas and the prepared? -Caprolactam as a main component Caprolactam mixture 18 to obtain a low-boiling component 20 and a high boiling component 19 from the crude epsilon -caprolactam mixture 18, and a second distillation step 5), a part or the whole amount of the preparation lower alcohol (15) is purified Class has an alcohol recovery step (6).

That is, in the present embodiment, cyclohexanone oxime is evaporated under the coexistence of an inert gas (8), a lower alcohol (9) and water (10) to obtain a cyclohexanone oxime (7), an inert gas (8), a lower alcohol 9) and water (10); (7) is converted into? -Caprolactam to obtain a reaction gas (12) containing? -Caprolactam, a lower alcohol and an inert gas, and a reaction gas Reaction step (2) to be obtained; (13) as an impurity is separated from the reaction solution obtained by cooling the reaction gas (12) to obtain a mixed gas (14) containing? -Caprolactam, a lower alcohol and an inert gas, Distillation step (3); A low alcohol separation step (4) for separating a crude alcohol (15) containing a lower alcohol and an inert gas from the mixture gas (14) and a crude? -Caprolactam mixture (18) containing? -Caprolactam; A second distillation step (5) for separating the low boiling point component (20) and the high boiling point component (19) as impurities from the prepared? -Caprolactam mixture (18); And a lower alcohol recovery step (6) for purifying a part or the whole of the prepared lower alcohol (15) to obtain a recovered lower alcohol.

Further, the second distillation step (5) may consist of a plurality of distillation steps. More specifically, it is as follows.

In the evaporation step (1), the cyclohexanone oxime (7), the inert gas (8), the lower alcohol (9) and the water (10) are supplied to the evaporator (1), and the cyclohexanone oxime (9) and water (10) and evaporated to obtain a raw material gas (11) containing cyclohexanone oxime (7), a lower alcohol (9) and water (10). At this time, water may be mixed with cyclohexanone oxime in advance.

Subsequently, in the reaction step (2), the raw material gas 11 obtained in the evaporation step (1) is supplied to the reactor (2), the raw material gas (11) is brought into contact with the solid catalyst, To carry out a gas phase reaction and convert to 竜 -caprolactam to obtain a reaction gas 12 (hereinafter also referred to as a reaction mixture). The reaction gas 12 includes? -Caprolactam, a lower alcohol and an inert gas.

In the present specification, the gas phase reaction means reacting a raw material gas containing cyclohexanone oxime (7), lower alcohol (9) and water (10) in contact with a solid catalyst, to be.

Subsequently, in the first distillation step (3), the reaction gas (12) obtained in the reaction step (2) is supplied to the first distillation column (3), cooled and cooled, and a high boiling point component ) Is separated to obtain a mixed gas 14 containing? -Caprolactam, a lower alcohol and an inert gas.

Examples of the inert gas include nitrogen, argon, and carbon dioxide.

Subsequently, in the lower alcohol separation step (4), the mixed gas (14) obtained in the first distillation step (3) is supplied to the lower alcohol recovery column (4), and a lower alcohol and an inert gas And the crude epsilon -caprolactam mixture (18) containing epsilon -caprolactam are separated. Here, the amount of water contained in the crude lower alcohol (15) containing an inert gas can be adjusted by distillation conditions.

In the second distillation step (5), the crude? -Caprolactam mixture (18) obtained in the lower alcohol separation step (4) is fed to the second distillation column (5), and the crude? -Caprolactam mixture The low boiling point component (20) and the high boiling point component (19) as impurities are separated to obtain crude epsilon -caprolactam (21).

Here, the low boiling point component means a component whose boiling point is lower than? -Caprolactam.

The high boiling point component means a component having a boiling point higher than that of? -Caprolactam.

In the lower alcohol recovery step (6), a part or the whole of the prepared lower alcohol (15) obtained in the lower alcohol separation step (4) is supplied to the lower alcohol refining apparatus (6) and impurities such as ammonia and amines ) Is removed to obtain a recovered lower alcohol (refined lower alcohol) 17 containing an inert gas. The recovered lower alcohol (17) is supplied to the evaporator (1) and reused after the evaporation process (1).

1 is an example, and the present invention is not limited to what is shown in FIG. Hereinafter, the present invention will be described focusing on a gas phase reaction using a recovered lower alcohol and a solid catalyst in the presence of a lower alcohol.

The solid catalyst is a solid catalyst for the production of ε-caprolactam used for converting cyclohexanone oxime to ε-caprolactam by Beckmann rearrangement reaction in vapor phase. As such solid catalysts, various ones have been proposed in the past, among which zeolite is preferable, pentasil-type zeolite, and more preferably MFI zeolite.

The zeolite may be a crystalline silica whose skeleton is substantially composed of silicon and oxygen, or may be a crystalline metal silicate or the like including elements other than silicon and oxygen, such as a metal element, have. As the elements other than silicon and oxygen, for example, Be, B, Al, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Sb, La, And may include two or more of these as required. The atomic ratio of silicon to these elements is preferably 50 or more, and more preferably 500 or more.

The zeolite can be obtained by subjecting a crystal obtained by subjecting a silicon compound, a quaternary ammonium compound, water and, if necessary, a metal compound or the like, as a raw material to hydrothermal synthesis, drying and calcining, then treating with ammonia or ammonium salt, Followed by drying.

The particle diameter of the solid catalyst is preferably 0.0001 to 5 mm, more preferably 0.001 to 3 mm. Further, the solid catalyst may be, for example, a molded article substantially containing only a catalyst component, or may be a catalyst component supported on a carrier.

The lower alcohol preferably has 6 or less carbon atoms. Specific examples thereof include alcohols such as methanol, ethanol, 1-propanol (n-propyl alcohol), 2-propanol (isopropyl alcohol) Propanol (isobutyl alcohol), 1-pentanol (n-pentyl alcohol), 1-hexanol (n-hexyl alcohol) and 2,2,2-tri And fluoroethanol. Of these, methanol, ethanol, 1-propanol, 2-propanol and 1-butanol are preferable, and methanol and ethanol are more preferable because the selectivity of? -Caprolactam and the catalyst life are particularly improved. Methanol and ethanol are most preferred from an industrial point of view.

Here, the selectivity means the production rate of? -Caprolactam in the reaction product.

The lower alcohol to be coexisted may be one kind or two or more kinds, and in the case of two or more kinds, the combination and proportion thereof may be arbitrarily selected. However, considering the handling property and the like, the lower alcohol is preferably one kind.

In the present invention, the gas phase reaction is carried out, and the lower alcohol is recovered from the reaction mixture (for example, the reaction gas 12 in Fig. 1) obtained by the gas phase reaction, and the recovered lower alcohol Recovered lower alcohol (17) in the vapor phase reaction) is reused in a new gas phase reaction.

That is, the lower alcohol coexisting in the gas phase reaction contains the recovered lower alcohol.

As the recovered lower alcohol, various ones may be used depending on the recovery method thereof, and one kind thereof may be used alone, or two or more kinds may be used in combination. When two or more of them are used in combination, their combination and ratio can be arbitrarily selected.

As the lower alcohol to be coexisted, only a recovered lower alcohol may be used, or a recovered lower alcohol and a recovered lower alcohol (for example, a lower alcohol (9) shown in Fig. 1, hereinafter referred to as "non-recovered lower alcohol" ) May be used in combination. And the purity of the recovered lower alcohol. Normally, at least a part of the recovered lower alcohol is purified and used, whereby the amount of the impurity can be easily reduced to the desired amount even with the recovered lower alcohol alone. On the other hand, recovered lower alcohols usually have a higher impurity content than non-recovered lower alcohols. Therefore, depending on the purity thereof, more purification operations may be required to reduce these impurities. However, The amount of impurities during the gas phase reaction may be easily reduced even if the operation is omitted or reduced.

The recovered lower alcohol is obtained, for example, by separating a gas containing a lower alcohol as a main component (for example, the prepared lower alcohol (15) in Fig. 1) from the reaction mixture of the gas phase reaction. The gas containing the lower alcohol as a main component can be separated from the reaction mixture, for example, by distillation. The lower alcohol obtained by distillation is hereinafter also referred to as distilled lower alcohol (15).

In the vapor phase reaction, in the operation mode in which the reaction liquid 12 is continuously withdrawn while the raw material gas 11 is continuously supplied, the vapor phase reaction is carried out by using the same reactor and, first, the recovered lower alcohol or the recovered lower alcohol In the vapor phase reaction in which cyclohexanone oxime is brought into contact with a solid catalyst in the coexistence of a lower alcohol to convert cyclohexanone oxime into? -Caprolactam or another production process of? -Caprolactam, Means a gas phase reaction in which cyclohexanone oxime is brought into contact with a solid catalyst in the presence of a lower alcohol to convert cyclohexanone oxime into epsilon -caprolactam. The separated gas (gas containing the lower alcohol as a main component) may be used as it is or partially or entirely purified by a known method. In general, it is preferable to purify a part of the catalyst before use.

The gas 15 containing the lower alcohol as a main component can be purified by, for example, introducing it into a gas absorption column or the like, condensing it by cooling, and reducing impurities by distillation. Condensation means that a gas containing a lower alcohol as a main component is made into a liquid mixture having a lower alcohol as a main component.

As the recovered lower alcohol, it is preferable to mix the purified lower alcohol (17) obtained by condensing the prepared lower alcohol (15) as described above.

Specifically, the purified lower alcohol can be obtained by, for example, distilling a reaction mixture obtained in a gas phase reaction, separating a gas containing a lower alcohol as a main component, cooling a part of the gas by condensation to obtain a liquid mixture containing a lower alcohol as a main component , And further, distilling the liquid mixture to obtain a distilled lower alcohol.

In the present invention, it is preferable that at least a part of the recovered lower alcohol is obtained by distilling a gas containing a lower alcohol as a main component from a reaction mixture of the above-mentioned vapor phase reaction, condensing and condensing a part thereof, and further distilling .

The lower alcohol preferably has a mass ratio (amount of lower alcohol (mass) / amount of cyclohexanone oxime (mass)) to cyclohexanone oxime in the gas phase reaction is preferably 0.1 to 20, more preferably 0.1 to 10 , Particularly preferably from 0.3 to 8, in the reaction system.

The molar percentage (a) of the ammonia ([ammonia (mol) / lower alcohol (moles)] x 100) in the reaction system during the gas phase reaction is preferably 0 or more and less than 14 and is preferably 13 or less.

The molar percentage (b) ([water (mole number) / lower alcohol (mole number)] x 100) of water in the reaction system during the gas phase reaction is preferably greater than 0 and less than 11 and not greater than 10.

In addition, water is a necessary component for proceeding the dislocation reaction smoothly. From this viewpoint, the amount of water in the reaction system during the gas phase reaction is preferably 0.06 mol or more per 1 mol of cyclohexanone oxime.

The amines may be any of primary amines, secondary amines and tertiary amines, monoamines and polyamines, in which the hydrogen atom of ammonia (NH ₃ ) is substituted by a hydrocarbon group. Representative examples of the amines include monomethylamine as the primary amine, dimethylamine as the secondary amine, and trimethylamine as the tertiary amine, respectively.

Here, it is expected that ammonia is generated upon hydrolysis of cyclohexanone oxime, and amines are reacted with ammonia and lower alcohol.

The molar percentage (c) ([amines (moles) / lower alcohols (moles)] x 100) of the amines in the reaction system during the gas phase reaction is preferably 0 or more and less than 7.5 and is preferably 7 or less.

As a main source of introduction of water, ammonia and amines, recovered lower alcohols can be exemplified. Thus, by controlling the amount or purity of the recovered lower alcohol, the amount of water, ammonia, and amines in the reaction system can be easily controlled.

For example, the mixing ratio of the recovered lower alcohol and the non-recovered lower alcohol (recovered lower alcohol (mass%): non-recovered lower alcohol (mass%)) is preferably from 10: 0 to 10:10, : 2 is more preferable.

In addition, as a method for controlling the amount of water, ammonia and amines, there can be mentioned water, ammonia and amines by appropriately feeding a gas of non-recovering lower alcohol into the reaction system while detecting the amount of water, ammonia and amines in the gas phase reaction, And the like.

The amount of water can be measured by Karl Fischer method, and the amount of ammonia and amines can be measured by a known method such as ion chromatography.

In the present invention, a molecular oxygen-containing gas may coexist in the reaction system. As the molecular oxygen-containing gas, it is preferable to use air because it is economical. It is preferable that the concentration of molecular oxygen is out of the explosion composition range.

The amount of molecular oxygen in the reaction system during the gas phase reaction is preferably 0.1 to 10 moles, more preferably 0.3 to 5 moles, per 1 mole of cyclohexanone oxime.

The gas phase reaction can be performed by a gas-phase catalytic reaction in a conventional fixed bed system, a fluidized bed system or a mobile bed system. The raw cyclohexanone oxime reacts by contacting with the catalyst layer in the gaseous state. The lower alcohol may be preliminarily mixed with the cyclohexanone oxime in the gaseous state, or may be fed separately to the cyclohexanone oxime. In the case of the fixed bed method, it is preferable to pass the catalyst layer in a state in which cyclohexanone oxime and a lower alcohol are sufficiently mixed. On the other hand, in the case of the fluidized bed method, it is not always necessary that the cyclohexanone oxime and the lower alcohol be mixed in advance, and they may be supplied separately to the reactor, or the lower alcohol may be separately supplied. Further, in the case of the fluidized bed method, the lower alcohol may be supplied upstream of the cyclohexanone oxime.

In the case of using a molecular oxygen-containing gas, the molecular oxygen-containing gas can be mixed with a lower alcohol and cyclohexanone oxime or mixed with a lower alcohol, and further supplied to the upstream side of the reaction system rather than the cyclohexanone oxime It is possible.

The gas phase reaction may be performed by coexisting vapor of a compound inert to the reaction, such as benzene, cyclohexane, or toluene, as a diluting gas, or by coexistence of an inert gas such as nitrogen or carbon dioxide.

The gas phase reaction is preferably carried out under atmospheric pressure or under reduced pressure at atmospheric pressure or lower.

The reaction temperature during the gas phase reaction is preferably 250 to 500 占 폚, more preferably 300 to 450 占 폚, and particularly preferably 300 to 400 占 폚. By setting the amount to be the lower limit value or more, the reaction rate is improved and the selectivity of? -Caprolactam is further improved.

In addition, by setting it to the upper limit value or less, thermal decomposition of the cyclohexanone oxime is suppressed, and the selectivity of? -Caprolactam is further improved.

The space velocity (WHSV) of the cyclohexanone oxime during the gas phase reaction is preferably 0.1 to 40 h ^-1 (that is, the supply rate of the cyclohexanone oxime per 1 kg of the catalyst is 0.1 to 40 kg / h), preferably 0.2 to 20 h ^-1 , More preferably from 0.5 to 10 h &lt; ^{-1 &} gt ;.

The ε-caprolactam produced by the gas phase reaction (dislocation reaction) can be separated from the reaction mixture by known methods. For example, purified epsilon -caprolactam is obtained by cooling and condensing the reaction product gas, and subsequently, by extraction, distillation, crystallization or the like.

The solid catalyst can burn (remove) the carbonaceous substance adhered in the gas phase reaction by an oxygen-containing gas at a temperature of 200 to 600 ° C, can easily be revived to its original performance, have. The removal of the carbonaceous substance may be performed by coexisting with an oxygen-containing gas.

The combustion treatment by the oxygen-containing gas may be carried out at a temperature of 200 to 600 DEG C under a constant temperature condition and under a condition of heating in multiple stages.

The oxygen-containing gas is usually air, but air or oxygen may be diluted with an inert gas such as nitrogen, argon or carbon dioxide.

The oxygen concentration in the oxygen-containing gas is preferably 1 to 30% by volume, more preferably 5 to 25% by volume.

The present invention is based on the assumption that, as a raw material for the dislocation reaction of cyclohexanone oxime, the recovered product from the reaction product of the dislocation reaction is reused. Further, attention is focused on impurities that can be generated in the dislocation reaction of cyclohexanone oxime, and ammonia, water and amines are specified as impurities capable of inhibiting this dislocation reaction in the presence of excess, Is limited to a limited range. The conventional process for producing ε-caprolactam which performs the dislocation reaction of cyclohexanone oxime is an extremely excellent process industrially in terms of high yield. According to the present invention, the reaction rate in the dislocation reaction of cyclohexanone oxime and The selectivity can be maintained at a very high level, and the catalyst can be reused, so that further improvement of the yield of epsilon -caprolactam and cost reduction are possible.

<Examples>

Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to the following embodiments.

In the following description, the space velocity WHSV (h ^-1 ) was calculated by dividing the feed rate (g / h) of cyclohexanone oxime by the catalyst weight (g). The analysis of cyclohexanone oxime and epsilon -caprolactam was carried out by gas chromatography. The reaction rate of cyclohexanone oxime and the selectivity of epsilon -caprolactam were determined by X-number of moles of the supplied cyclohexanone oxime, The mole number of cyclohexanone oxime was calculated as Y, and the number of moles of produced? -Caprolactam was calculated as Z, respectively.

(%) Of cyclohexanone oxime = [(X-Y) / X] x 100

Selectivity (%) of? -caprolactam = [Z / (X-Y)] 100

[Example 1]

0.75 g of particles having a particle size of 0.3 mm or less and containing MFI zeolite containing crystalline silica (Si / Al atomic ratio of 147000) as a main component and having a particle size of 0.3 mm or less were packed in a quartz glass reaction tube having an inner diameter of 1 cm to form a catalyst layer, / h at 340 占 폚 for 1 hour under nitrogen gas flow. Subsequently, a mixture of methanol / cyclohexanone oxime = 1.3 / 1 (mass ratio) under nitrogen gas flow at 0.72 L / h was fed at a feeding rate of 6.9 g / h (WHSV of cyclohexanone oxime = 4 h ^-1 ) The reaction tube was fed and the reaction was carried out for 10 hours while the temperature of the catalyst layer was maintained at 380 占 폚. Then, the amount of impurities in the reaction system at this time was made to satisfy the following relationship.

(a) [Ammonia (Mole) / Methanol (Mole)]] 100 = 0

(b) [water (moles) / methanol (moles)] x 100 = 6.4

(c) [Amines (moles) / Methanol (moles)] x 100 = 0

The reaction solution was collected from the initiation of the reaction to 10 hours, and the reaction rate of cyclohexanone oxime and the selectivity of? -Caprolactam in the reaction solution were calculated. The results are shown in Table 1.

The yield of? -Caprolactam in this example was 94.9%.

[Example 2]

As shown in Table 1, epsilon -caprolactam was prepared in the same manner as in Example 1 except that the molar percentage (a) of ammonia was changed to 5.9 instead of 0. [

The yield of? -caprolactam was 95.0%.

[Example 3]

As shown in Table 1, epsilon -caprolactam was produced in the same manner as in Example 1 except that the molar percentage (a) of ammonia was changed to 8.7 instead of 0. [

The yield of? -caprolactam was 95.1%.

[Comparative Example 1]

As shown in Table 1,? -Caprolactam was prepared in the same manner as in Example 1 except that the molar percentage (a) of ammonia was changed to 18 instead of 0. [

The yield of? -caprolactam was 93.2%.

[Example 4]

In the same manner as in Example 1, 0.75 g of a solid catalyst was charged into a quartz glass reaction tube having an inner diameter of 1 cm to form a catalyst layer and preheated at 340 캜 for 1 hour under nitrogen gas flow at 0.72 L / h. Subsequently, a mixture of methanol / cyclohexanone oxime = 1.3 / 1 (mass ratio) under a flow of nitrogen gas at 0.72 L / h was fed at a feed rate of 6.9 g / h (WHSV of cyclohexanone oxime: 4 h ^-1 ) The mixture was fed to the reaction tube and reacted for 2 hours while the temperature of the catalyst layer was maintained at 380 ° C. Then, the amount of impurities in the reaction system at this time was made to satisfy the following relationship.

(a) [Ammonia (Mole) / Methanol (Mole)]] 100 = 0

(b) [water (moles) / methanol (moles)] x 100 = 6.4

(c) [Amines (moles) / Methanol (moles)] x 100 = 0

The reaction rate of cyclohexanone oxime and the selectivity of? -Caprolactam were calculated in the same manner as in Example 1 at the lapse of 2 hours from the start of the reaction.

The yield of? -caprolactam was 95.6%.

[Example 5]

As shown in Table 1,? -Caprolactam was prepared in the same manner as in Example 4 except that the molar percentage (b) of water was changed to 8.3 instead of 6.4.

The yield of? -caprolactam was 95.3%.

[Comparative Example 2]

As shown in Table 1,? -Caprolactam was prepared in the same manner as in Example 4 except that the molar percentage (b) of water was changed to 14 instead of 6.4.

The yield of? -caprolactam was 94.6%.

[Example 6]

In the same manner as in Example 1, 0.75 g of a solid catalyst was charged into a quartz glass reaction tube having an inner diameter of 1 cm to form a catalyst layer and preheated at 340 캜 for 1 hour under nitrogen gas flow at 0.72 L / h. Subsequently, a mixture of methanol / cyclohexanone oxime = 1.3 / 1 (mass ratio) under a flow of nitrogen gas at 0.72 L / h was fed at a feed rate of 6.9 g / h (WHSV of cyclohexanone oxime: 4 h ^-1 ) The mixture was fed to the reaction tube and reacted for 2 hours while the temperature of the catalyst layer was maintained at 380 ° C. Then, the amount of impurities in the reaction system at this time was made to satisfy the following relationship.

(a) [Ammonia (Mole) / Methanol (Mole)]] 100 = 0

(b) [water (moles) / methanol (moles)] x 100 = 6.4

(c) [Amines (moles) / Methanol (moles)] x 100 = 0

The reaction rate of cyclohexanone oxime and the selectivity of? -Caprolactam were calculated in the same manner as in Example 1 at the elapse of 6 hours from the start of the reaction.

The yield of? -caprolactam was 95.8%.

[Example 7]

As shown in Table 1,? -Caprolactam was produced in the same manner as in Example 6 except that trimethylamine was used as an amine and the molar percentage (c) thereof was changed to 3.6 instead of 0. [

The yield of? -caprolactam was 95.6%.

[Comparative Example 3]

As shown in Table 1,? -Caprolactam was prepared in the same manner as in Example 6 except that trimethylamine was used as an amine and the molar percentage (c) thereof was changed to 7.5 instead of 0. [

The yield of? -caprolactam was 95.5%.

[Referential Example 1]

A part or the whole amount of the distilled lower alcohol obtained in the lower alcohol separation step (4) was cooled to 7 to 30 캜 and liquefied. The liquefied lower alcohol was subjected to distillation at 80 DEG C and 175 kPaA to obtain a recovered lower alcohol (17).

Methanol thus obtained contained 0.49% of water, 0.01% of ammonia, and 1.4% of trimethylamine. Water was added to the obtained methanol to make the water content 4.0%. This was mixed with cyclohexanone oxime in a ratio of 1.3 / 1 (mass ratio) and used in the reaction.

[Example 8]

In the same manner as in Example 1, 0.75 g of a solid catalyst was charged into a quartz glass reaction tube having an inner diameter of 1 cm to form a catalyst layer and preheated at 340 캜 for 1 hour under nitrogen gas flow at 0.72 L / h. Subsequently, the 0.72L / h WHSV of a methanol / cyclohexanone oxime = 1.3 / 1 (weight ratio) mixture of 6.9g / h (cyclohexanone oxime prepared in Reference Example 1 under a flow of nitrogen gas at 4h ^-1 ), And the reaction was carried out for 10 hours while the temperature of the catalyst layer was maintained at 380 占 폚. The amount of impurities in the reaction system at this time satisfied the following relationship.

(a) [Ammonia (mole number) / Methanol (mole number)] × 100 = 0.02

(b) [water (moles) / methanol (moles)] x 100 = 7.2

(c) [Amines (moles) / Methanol (moles)] x 100 = 0.77

The reaction solution was collected from the start of the reaction to 10 hours, and the reaction rate of cyclohexanone oxime and the selectivity of? -Caprolactam were calculated in the same manner as in Example 1.

The yield of? -caprolactam was 95.3%.

From the above results, the following points can be confirmed.

In Examples 1 to 7, both the selectivity and the reaction rate were high, and the catalytic activity was good.

On the other hand, as the molar percentage (a) of ammonia increased, the reaction rate in Comparative Example 1 was good, but the selectivity was lower than in Examples 1 to 3 and the yield was lowered.

In addition, although the reaction rate was good in Comparative Example 2, the selectivity was lowered than in Examples 4 to 5 because the molar percentage (b) of water increased.

In addition, although the reaction rate was good in Comparative Example 3, the selectivity was lowered than in Examples 6 to 7 because the molar percentage (c) of the amines was increased.

As described above, by selecting ammonia, water, and amines as the impurities that define the mixing amount in the reaction system and limiting the amount of ammonia, water, and amines to a limited range, the reaction rate and selectivity in the dislocation reaction of cyclohexanone oxime It can be confirmed that it can be maintained at a high level.

The present invention is applicable to the production of? -Caprolactam by a gas phase reaction using a solid catalyst.

According to the present invention, it is possible to provide a process for producing ε-caprolactam which is excellent in the selectivity in the dislocation reaction of cyclohexanone oxime.

In addition, by reusing the recovered lower alcohol, the amount of industrial waste can be reduced, and the burden on the environment can be reduced.

One… Evaporator, 2 ... Reactor, 3 ... First distillation tower, 4 ... Low alcohol recovery tower, 5 ... The second distillation tower, 6 ... Low alcohol refining device, 7 ... Cyclohexanone oxime, 8 ... Inert gas, 9 ... Low alcohol, 10 ... Water, 11 ... Raw material gas, 12 ... Reaction gas, 13 ... High boiling point component, 14 ... a mixed gas of? -caprolactam, a lower alcohol and an inert gas, 15? Preparative lower alcohol (including inert gas), 16 ... Impurities such as ammonia and amines, 17 ... Refined lower alcohol (including recovered lower alcohol, inert gas), 18 ... Preparative epsilon -caprolactam mixture, 19 ... High boiling point component, 20 ... Low boiling point component, 21 ... Preparative epsilon -caprolactam

Claims (5)

Subjecting a cyclohexanone oxime to a solid catalyst in the presence of a lower alcohol to effect a gas phase reaction to convert cyclohexanone oxime to? -Caprolactam, and
A process for producing ε-caprolactam, which comprises adjusting the amounts of water, ammonia and amines coexisting in a gaseous reaction system to the values of the following (1) to (3)
Wherein the lower alcohol comprises a recovered lower alcohol recovered from a reaction mixture obtained in a gas phase reaction.
(1) 0? {[Ammonia (moles) / lower alcohol (moles)] x 100} < 14
(2) 0 < {[water (moles) / lower alcohol (moles)] x 100} < 11
(3) 0? {[Amines (Mols) / Lower Alcohol (Mols))] × 100} <7.5 The method of claim 1, wherein the recovered lower alcohol comprises a distilled lower alcohol,
The distillation lower alcohol is obtained by distilling a reaction mixture obtained in the gas phase reaction and separating a gas containing a lower alcohol as a main component and cooling a part of the gas to obtain a liquid mixture containing a lower alcohol as a main component, Further comprising distilling the liquid mixture to obtain a distilled lower alcohol. &Lt; RTI ID = 0.0 &gt; 8. &lt; / RTI &gt; The process for producing ε-caprolactam according to claim 1 or 2, wherein the solid catalyst is zeolite. An evaporation step of evaporating a cyclohexanone oxime under the coexistence of an inert gas and a lower alcohol to obtain a raw material gas containing cyclohexanone oxime, an inert gas and a lower alcohol,
A reaction step of converting the cyclohexanone oxime into? -Caprolactam to obtain a reaction gas containing? -Caprolactam, a lower alcohol and an inert gas, by performing a gas phase reaction in which the raw material gas is brought into contact with a solid catalyst,
A first distillation step in which the reaction gas is cooled and cooled to separate a high boiling point component as an impurity from the obtained reaction liquid to obtain a mixed gas containing? -Caprolactam, a lower alcohol and an inert gas,
A lower alcohol separation step of separating a crude epsilon -caprolactam mixture containing a lower alcohol and an inert gas from the mixture gas and an epsilon -caprolactam,
A second distillation step of separating a low boiling point component and a high boiling point component as an impurity from the crude? -Caprolactam mixture to obtain? -Caprolactam, and
And a lower alcohol recovery step of purifying a part or the whole of the prepared lower alcohol to obtain a recovered lower alcohol,
The method for producing? -Caprolactam further comprises adjusting the amounts of water, ammonia and amines coexisting in the gaseous reaction system to the values of the following (1) to (3).
(1) 0? {[Ammonia (moles) / lower alcohol (moles)] x 100} < 14
(2) 0 < {[water (moles) / lower alcohol (moles)] x 100} < 11
(3) 0? {[Amines (Mols) / Lower Alcohol (Mols))] × 100} <7.5 The process for producing ε-caprolactam according to claim 4, wherein the solid catalyst is zeolite.

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