JP2003176125A - METHOD FOR MANUFACTURING PENTASIL ZEOLITE AND METHOD FOR MANUFACTURING epsilon-CAPROLACTAM - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing pentasil zeolite having excellent catalytic activity and reaction selectivity as a catalyst for the manufacture of ε-caprolactam with high reproducibility. <P>SOLUTION: The pentasil zeolite is manufactured by the following processes. (1) A process is mixing a silicon compound, water and tetra-n-propylammonium hydroxide to prepare a mixture liquid having 0.1 to 0.6 molar ratio of the hydroxide ions to silicon and ≤0.3 molar ratio of carboxylic acid ions to silicon. (2) A process subjects the mixture liquid prepared in the process (1) to a hydrothermal synthesis reaction. (3) A process is separating crystals from the reaction mixture obtained in the process (2). (4) A process is calcining the crystal separated in the process (3) and (5) a process subjects the crystal calcined in the process (4) to catalytic treatment with an aqueous solution containing ammonia and/or an ammonium salt. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a pentasil-type zeolite. The present invention also relates to a method for producing ε-caprolactam from cyclohexanone oxime using pentasil-type zeolite as a catalyst.

[0002]

2. Description of the Related Art Heretofore, as a method for producing a pentasil-type zeolite, a method has been proposed in which an alkylammonium compound is used as a so-called templating agent to carry out a hydrothermal synthesis reaction of a silicon compound (for example, JP-B-46-10064).
JP-A-54-72795, JP-A-59-
164617, etc.). And as an example of an organic synthesis reaction using this pentasil-type zeolite as a catalyst,
A method for producing ε-caprolactam by subjecting cyclohexanone oxime to a Beckmann rearrangement reaction in a gas phase has been proposed (for example, JP-A-2-250866).
Japanese Patent Laid-Open No. 2-275850).

[0003]

DISCLOSURE OF THE INVENTION From the viewpoint of using pentasil-type zeolite mainly as a catalyst for producing ε-caprolactam, the present inventors have proposed tetra-n hydroxide hydroxide as a template agent.
When a method for producing a pentasil-type zeolite using -propylammonium was examined, the conventional method may not have sufficient catalytic activity or reaction selectivity of the obtained pentasil-type zeolite, and the reproducibility I was not satisfied with the points.

Therefore, an object of the present invention is to solve the above problems and to provide a method for producing a pentasil-type zeolite having excellent catalytic activity and reaction selectivity with good reproducibility. Another object of the present invention is to provide a method for producing ε-caprolactam from cyclohexanone oxime in high yield with good reproducibility, using the pentasil-type zeolite thus obtained as a catalyst.

[0005]

Means for Solving the Problems As a result of intensive studies conducted by the present inventors, tetra-n-propylammonium hydroxide, which is commonly available, contains impurities such as formate ion, acetate ion and propionate ion. It was found that carboxylate ions are contained, and these carboxylate ions affect the catalytic activity and reaction selectivity of the pentasil-type zeolite obtained. As a result of further research, the amount of hydroxide ion and carboxylate ion in the raw material mixture was controlled within a specific range, and the mixture was subjected to a hydrothermal synthesis reaction and then subjected to a specific step. As a result, they have found that the above object can be achieved, and completed the present invention.

That is, according to the present invention, (1): a silicon compound, water and tetra-n-propylammonium hydroxide are mixed, and the molar ratio of hydroxide ion to silicon is 0.1 to 0.6. A step of preparing a mixed solution having a molar ratio of carboxylate ion to silicon of 0.3 or less, (2): a step of subjecting the mixed solution prepared in the step (1) to a hydrothermal synthesis reaction, (3) : A step of separating crystals from the reaction mixture obtained in the step (2), (4): a step of firing the crystals separated in the step (3),
And (5): a method for producing a pentasil-type zeolite by a step of subjecting the crystal fired in the step (4) to a contact treatment with an aqueous solution containing ammonia and / or an ammonium salt.

In the present invention, (1): a silicon compound, water and tetra-n-propylammonium hydroxide are mixed, and the molar ratio of hydroxide ion to silicon is 0.1 to 0.6. A step of preparing a mixed solution having a molar ratio of carboxylate ion to silicon of 0.3 or less, (2): a step of subjecting the mixed solution prepared in the step (1) to a hydrothermal synthesis reaction, (3): Separating the crystals from the reaction mixture obtained in step (2), (4): firing the crystals separated in step (3),
And (5): the pentasil-type zeolite obtained by a series of steps of contact-treating the crystal calcined in step (4) with an aqueous solution containing ammonia and / or ammonium salt is used as a catalyst, and the presence of this catalyst Below, it relates to a method for producing ε-caprolactam by subjecting cyclohexanone oxime to a Beckmann rearrangement reaction in a gas phase.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
In the present invention, as the step (1), a silicon compound,
By mixing water, tetra-n-propylammonium hydroxide and other compounds as necessary, a mixed solution used as a raw material solution for hydrothermal synthesis is prepared.

As the silicon compound, tetraalkyl orthosilicates such as tetramethyl orthosilicate, tetraethyl orthosilicate, tetrapropyl orthosilicate, tetrabutyl orthosilicate and the like are preferable, and if necessary, two or more kinds thereof may be used. Among them, tetraethyl orthosilicate is particularly preferable. Also, tetra-n-hydroxide
As propylammonium, an aqueous solution thereof is usually used.

The molar ratio of hydroxide ion to silicon in the above mixture must be adjusted to 0.1 to 0.6, preferably 0.2 to 0.5. When this molar ratio is less than 0.1, the particle size of the obtained zeolite becomes large and the outer surface area thereof decreases, so that the catalytic activity may not be sufficient. On the other hand, if this molar ratio exceeds 0.6, the particle size of the obtained zeolite will be small and the handling properties such as filterability may not be good.

The molar ratio of carboxylate ion to silicon in the above mixture should be adjusted to 0.3 or less, preferably 0.2 or less, more preferably 0.1 or less.
It is the following. If this molar ratio exceeds 0.3, the catalytic activity and reaction selectivity of the obtained zeolite will be insufficient.

Further, the molar ratio of water to silicon in the above mixed solution is preferably adjusted to 5 to 100, more preferably 10 to 60. The molar ratio of tetra-n-propylammonium ion to silicon is
It is preferably adjusted to 0.1 to 0.6, and more preferably 0.2 to 0.5.

The molar ratio of the hydroxide ion to silicon and the molar ratio of tetra-n-propylammonium ion to silicon in the above mixture should be adjusted by adjusting the amount of tetra-n-propylammonium hydroxide used to the silicon compound. The molar ratio of hydroxide ions may be adjusted by further using sodium hydroxide and / or potassium hydroxide as a mixed raw material in a predetermined amount, if necessary. The molar ratio of -n-propylammonium ion may be adjusted, if necessary, by further using a predetermined amount of a tetra-n-propylammonium salt such as tetra-n-propylammonium bromide as a mixed raw material. When sodium hydroxide and / or potassium hydroxide is used as a mixed raw material, the molar ratio of sodium and / or potassium to silicon in the mixed solution is 0.0
It is preferably adjusted to 1 to 0.1.

Further, the molar ratio of carboxylate ion to silicon in the above mixture is such that each raw material, particularly tetrahydroxide
It can be adjusted by controlling the content of carboxylate ion contained in n-propylammonium. For this purpose, as each raw material, from among commercially available products and prepared products,
It is necessary to select one having a carboxylate ion content of not more than a predetermined amount. On the other hand, if the molar ratio of the carboxylate ion to silicon in the mixed solution is within a predetermined value or less, if necessary, for example, formic acid, acetic acid, carboxylic acid such as propionic acid or a salt thereof is used as a mixed raw material. You may use a predetermined amount.

Regarding the content of each component contained in the above mixed solution, for example, silicon is an inductively coupled plasma (IC).
P) By emission analysis, tetra-n-propylammonium ion, carboxylate ion, carbonate ion and bromide ion can be determined by ion chromatography, and sodium ion and potassium ion can be determined by atomic absorption spectrometry. Further, the content of hydroxide ions in the above mixed solution is calculated from the total content of basic ions obtained by neutralization titration with an acid (for example, 0.2N hydrochloric acid), It can be determined by subtracting the content of basic ions other than oxide ions.

In the step (1), if necessary, at least one selected from aluminum compounds, gallium compounds, boron compounds, titanium compounds, zirconium compounds and zinc compounds may be mixed. Examples include alkoxides such as nitrates and isopropoxide. Regarding the amount of these compounds used, the molar ratio of silicon to the total of aluminum, gallium, boron, titanium, zirconium and zinc in the mixed solution is from the viewpoint of heat resistance of the obtained zeolite and reaction selectivity as a catalyst. It is usually set to 50 or more, preferably 500 or more.

The reaction mixture containing crystals can be obtained by subjecting the mixed solution prepared in step (1) to a hydrothermal synthesis reaction in step (2). Regarding the conditions of this hydrothermal synthesis reaction, the temperature is usually in the range of 80 to 160 ° C., and the time is in the range of 1 to 200 hours.

Crystals are separated from the reaction mixture obtained in step (2) as step (3). This separation may be carried out by filtration or decantation, for example, but filtration is preferred.

On the other hand, in the residual liquid generated in step (3) after separating the crystals from the reaction mixture obtained in step (2), silicic acid or its oligomer, tetra-n, which is an active ingredient, is usually contained. -Since it contains propylammonium ion and the like, at least a part of this residual liquid can be recycled by circulating it to the step (1).

When tetraalkyl orthosilicate such as tetraethyl orthosilicate is used as a silicon compound as a raw material, alcohol such as ethanol is usually contained in the residual liquid. When such a residual liquid is recycled, it is preferable to remove all or part of the alcohols from the residual liquid by distillation or the like, and then circulate it in step (1).

When the above residual liquid is recycled,
It is preferable to store under a nitrogen gas atmosphere or an air atmosphere from which carbon dioxide is removed so that the amount of hydroxide ions does not decrease due to the dissolution of carbon dioxide. Further, when the residual liquid contains alcohols, it is preferable to carry out storage and distillation under a nitrogen gas atmosphere so that the alcohols are not oxidized by oxygen and the amount of carboxylate ions is not increased.

The crystal separated in step (3) is dried if necessary, and then subjected to firing in step (4). This firing is usually performed in air, nitrogen or a mixed gas thereof in the temperature range of 400 to 600 ° C.

The crystal calcined in step (4) is contact-treated with an aqueous solution containing ammonia and / or ammonium salt in step (5). Examples of the ammonium salt include ammonium nitrate, ammonium chloride, ammonium sulfate, etc. Among them, ammonium nitrate is preferable.

Regarding the conditions of this contact treatment, the temperature is usually in the range of 50 to 100 ° C., and the time is in the range of 0.1 to 12.
It is a range of time. When an aqueous solution containing ammonia or an aqueous solution containing ammonia and an ammonium salt is used as the aqueous solution, the pH of the aqueous solution is preferably in the range of 9 to 13. By this contact treatment, the catalytic activity of the obtained zeolite can be further improved.
The crystal after the contact treatment may be dried and then fired again, if necessary.

The pentasil-type zeolite thus obtained can be used for various purposes such as a catalyst for organic synthesis reaction. Above all, when producing ε-caprolactam by subjecting cyclohexanone oxime to a Beckmann rearrangement reaction in a gas phase. It can be suitably used as a catalyst.

As the above-mentioned cyclohexanone oxime,
For example, it may be produced by reacting cyclohexanone with a salt such as hydroxylamine or a sulfate thereof, or by reacting cyclohexanone with ammonia and hydrogen peroxide in the presence of a catalyst such as titanosilicate. It may be manufactured by The cyclohexanone may be, for example, one produced by subjecting cyclohexane obtained by hydrogenation of benzene to an oxygen oxidation reaction, or by oxidizing cyclohexanol obtained by partial hydrogenation of benzene ( It may be one produced by a (dehydrogenation) reaction.

The Beckmann rearrangement reaction may be carried out in a fixed bed system or a fluidized bed system, and the reaction temperature is usually 250 to 500 ° C., preferably 300 to 450.
℃, more preferably in the range of 300 ~ 400 ℃,
The reaction pressure is usually in the range of 10 kPa to 0.5 MPa. Further, the feed rate (kg / h) of the starting material cyclohexanone oxime per 1 kg of the zeolite catalyst, that is, the space velocity WHSV of the starting material cyclohexanone oxime
(H ^-1) is usually 0.1～40H ^-1, preferably 0.2
˜20 h ⁻¹ , more preferably 0.5 to 10 h ⁻¹ .

As a method for separating and purifying ε-caprolactam from the reaction mixture obtained by the Beckmann rearrangement reaction, a known method can be appropriately adopted, for example, after the reaction product gas is cooled and condensed. , Ε-purified by subjecting the condensate to liquid-liquid distribution, distillation, crystallization, hydrogenation treatment, ion exchange, activated carbon treatment, etc.
Caprolactam can be obtained.

[0029]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited thereto. The space velocity WHS
V (h ^-1 ) was calculated by dividing the supply rate (kg / h) of cyclohexanone oxime by the catalyst weight (kg). Further, the conversion of cyclohexanone oxime and the selectivity of ε-caprolactam are respectively represented by the number of moles of supplied cyclohexanone oxime is X, the number of moles of unreacted cyclohexanone oxime is Y, and the number of moles of produced ε-caprolactam is Z. It was calculated by the following formula. Conversion of cyclohexanone oxime (%) = [(X-
Y) / X] × 100 ε-caprolactam selectivity (%) = [Z / (X−
Y)] × 100

Example 1 In a stainless steel autoclave having a volume of 1.5 liter,
Tetraethyl orthosilicate (Si (OC ₂ H ₅ ) ₄ ) 115 g, 3
8.8 wt% tetra-n-propylammonium hydroxide aqueous solution (total content of formate ion, acetate ion and propionate ion: 0.045 wt%, carbonate ion content: 0.055 wt%, containing potassium ion Amount: 0.
52 wt%) 72 g, 85 wt% potassium hydroxide 1.1
2 g and 316 g of water were added, and the mixture was vigorously stirred for 120 minutes. To the silicon in the obtained mixed liquid, water, tetra-
The molar ratios of n-propylammonium ion, hydroxide ion, carboxylate ion (total of formate ion, acetate ion and propionate ion), carbonate ion and potassium ion are 36, 0.25 and 0.28, respectively.
It was 0.001, 0.0012 and 0.048.

This mixed solution was kept at 105 ° C. for 48 hours for 30 hours.
Hydrothermal synthesis was performed by stirring at a rotation speed of 0 rpm or more. The resulting reaction mixture is filtered, and the crystals remaining on the filter are washed with
Was continuously washed with ion-exchanged water until it became 7.5 to 8, to obtain white crystals. This white crystal was heated at 110 ° C for 16
After drying for an hour, it was calcined at 530 ° C for 1 hour under nitrogen flow, and then at 530 ° C for 1 hour under air flow to obtain powdery white crystals. As a result of powder X-ray diffraction analysis of this powdery white crystal, it was identified as a pentasil-type zeolite.

7 g of the obtained powdery white crystal was placed in an autoclave, and 77 g of a 7.5 wt% ammonium nitrate aqueous solution and a 25 wt% ammonia aqueous solution 118 were placed therein.
195 g of a mixed solution with g was added, and the mixture was stirred at 90 ° C. for 1 hour, and then crystals were separated by filtration. The same treatment as described above with a mixed solution of an aqueous ammonium nitrate solution and an aqueous ammonia solution was repeated twice more, and the obtained crystals were washed with water and dried.

The dried crystals were sieved using a 24-48 mesh sieve, 0.375 g of which was used as a catalyst.
A quartz glass reaction tube having an inner diameter of 1 cm was filled to form a catalyst layer, and the catalyst layer was formed at 350 ° C. under a nitrogen flow of 4.2 L / h.
Preheated for an hour. Then, under a flow of 4.2 L / h of nitrogen, the temperature of the catalyst layer was lowered to 325 ° C., and then a mixture of cyclohexanone oxime / methanol = 1 / 1.8 (weight ratio) was supplied at a supply rate of 8.4 g / h. It was supplied to a reaction tube and reacted with cyclohexanone oxime. The space velocity WHSV at this time is 8 h ⁻¹ . 0.5 to 5.5 after starting the reaction
The reaction gas was collected over time and analyzed by gas chromatography. As a result, the conversion of cyclohexanone oxime was 99.3% and the selectivity of ε-caprolactam was 96.5%.

Example 2 In a stainless steel autoclave having a volume of 1.5 liter,
Tetraethyl orthosilicate _{(Si (OC 2 H 5)} 4) 115g, 2
1.4 wt% tetra-n-propylammonium hydroxide aqueous solution (total of formate ion, acetate ion and propionate ion content: 0.029 wt%, carbonate ion content: 0.824 wt%, containing potassium ion Amount: 0.
308 wt%) 135 g, formic acid 0.234 g, acetic acid 0.
889 g, propionic acid 0.047 g, tetra-n bromide
-Propyl ammonium 8.8g, 85 weight% potassium hydroxide 1.047g and water 254g were put, and it stirred violently for 120 minutes. Molar ratio of water, tetra-n-propylammonium ion, hydroxide ion, carboxylate ion (total of formate ion, acetate ion and propionate ion), carbonate ion and potassium ion to silicon in the obtained mixed liquid. Are 36, 0.
32, 0.29, 0.038, 0.034 and 0.0
It was 48.

Hydrothermal synthesis and subsequent operations were carried out on this mixed solution in the same manner as in Example 1. As a result, the conversion of cyclohexanone oxime was 99.3% and the selectivity of ε-caprolactam was 96.8%.

Example 3 In a stainless steel autoclave having a volume of 1.5 liter,
Tetraethyl orthosilicate _{(Si (OC 2 H 5)} 4) 115g, 1
8.5 wt% tetra-n-propylammonium hydroxide aqueous solution (total content of formate ion, acetate ion and propionate ion: 0.026 wt%, carbonate ion content: 0.951 wt%, containing potassium ion Amount: 0.
273% by weight) 186 g, formic acid 0.376 g, acetic acid 1.
409 g, propionic acid 0.071 g, tetra-n bromide
-Propyl ammonium 8.2g, 85 weight% potassium hydroxide 0.891g and water 209g were put, and it stirred violently for 120 minutes. Molar ratio of water, tetra-n-propylammonium ion, hydroxide ion, carboxylate ion (total of formate ion, acetate ion and propionate ion), carbonate ion and potassium ion to silicon in the obtained mixed liquid. Are 36, 0.
36, 0.33, 0.06, 0.054 and 0.04
It was 8.

Hydrothermal synthesis and subsequent operations were performed on this mixed solution in the same manner as in Example 1. As a result, the conversion of cyclohexanone oxime was 99.5% and the selectivity of ε-caprolactam was 97.0%.

Example 4 In a stainless steel autoclave having a capacity of 1.5 liters,
Tetraethyl orthosilicate (Si (OC ₂ H ₅ ) ₄ ) 115 g, 3
8.8 wt% tetra-n-propylammonium hydroxide aqueous solution (total content of formate ion, acetate ion and propionate ion: 0.045 wt%, carbonate ion content: 0.055 wt%, containing potassium ion Amount: 0.
(520 wt%) 106 g, acetic acid 5.35 g, tetra-n-propylammonium bromide 7.4 g, 85 wt% potassium hydroxide 0.816 g and water 295 g
Stir vigorously for 0 minutes. Water, tetra-n-propylammonium ion, with respect to silicon in the obtained mixed liquid,
The molar ratio of hydroxide ion, carboxylate ion (total of formate ion, acetate ion and propionate ion), carbonate ion and potassium ion is 36, respectively.
0.42, 0.39, 0.16, 0.002 and 0.
It was 048.

Hydrothermal synthesis and the subsequent operations were performed on this mixed solution in the same manner as in Example 1. As a result, the conversion of cyclohexanone oxime was 99.6% and the selectivity of ε-caprolactam was 96.3%.

Example 5 In a stainless steel autoclave having a volume of 1.5 liters,
Tetraethyl orthosilicate (Si (OC ₂ H ₅ ) ₄ ) 115 g, 3
8.8 wt% tetra-n-propylammonium hydroxide aqueous solution (total content of formate ion, acetate ion and propionate ion: 0.045 wt%, carbonate ion content: 0.055 wt%, containing potassium ion Amount: 0.
(520 wt%) 144 g, acetic acid 7.96 g, tetra-n-propylammonium bromide 5.9 g, 85 wt% potassium hydroxide 0.488 g and water 273 g
Stir vigorously for 0 minutes. Water, tetra-n-propylammonium ion, with respect to silicon in the obtained mixed liquid,
The molar ratio of hydroxide ion, carboxylate ion (total of formate ion, acetate ion and propionate ion), carbonate ion and potassium ion is 36, respectively.
0.54, 0.51, 0.24, 0.002 and 0.
It was 048.

Hydrothermal synthesis and subsequent operations were performed on this mixed solution in the same manner as in Example 1. As a result, the conversion of cyclohexanone oxime was 99.5% and the selectivity of ε-caprolactam was 96.1%.

The reaction kettle of Example 6 volume 30 m ^3, tetraethyl orthosilicate (S
i (OC ₂ H ₅ ) ₄ ) 2311 kg, 40.0 wt% tetra-n-propylammonium hydroxide aqueous solution (total content of formate ion, acetate ion and propionate ion:
0.025 wt%, carbonate ion content: 0.05 wt%, potassium ion content: 0.63 wt%) 1400
kg, 85% by weight potassium hydroxide (20.28 kg) and water (6518 kg) were added, and the mixture was vigorously stirred for 120 minutes. Molar amounts of water, tetra-n-propylammonium ion, hydroxide ion, carboxylate ion (total of formate ion, acetate ion and propionate ion), carbonate ion, and potassium ion relative to silicon in the obtained mixed liquid. The ratios are 36, 0.25, 0.28, 0.
It was 0005, 0.0011 and 0.048.

This mixed solution was kept at 105 ° C. for 48 hours for 30 hours.
Hydrothermal synthesis was performed by stirring at a rotation speed of 0 rpm or more. The obtained reaction mixture was filtered, and a filter residue and a filtrate were separated.
The filter residue crystals were continuously washed with ion-exchanged water until the pH of the washing liquid reached 7.5 to 8 to obtain white crystals. The white crystals were dried at 110 ° C. for 16 hours, calcined at 530 ° C. for 1 hour under nitrogen flow, and then at 530 ° C. for 1 hour under air flow to obtain powdery white crystals. As a result of powder X-ray diffraction analysis of this powdery white crystal, it was identified as a pentasil-type zeolite.

In the same manner as in Example 1, 7 g of the obtained powdery white crystal was treated with a mixed solution of an aqueous ammonium nitrate solution and an aqueous ammonia solution and the subsequent operations. As a result, the conversion of cyclohexanone oxime was 99.6% and the selectivity of ε-caprolactam was 9%.
It was 6.6%.

Example 7 To the filtrate separated by filtration in Example 6, 0.2 weight times of water was added, and this was added to a rectification column having 5 to 7 theoretical plates to obtain 300 Torr (40 kPa) and a kettle. Temperature 68-90
Distillation was carried out under the conditions of ℃ and reflux ratio of 1, and ethanol was distilled off. The content of tetra-n-propylammonium ion in the obtained kettle liquid was 8.24% by weight, the content of hydroxide ion was 0.773% by weight, formate ion,
The total content of acetate ion and propionate ion is 0.002% by weight, and the content of carbonate ion is 0.01
9% by weight, the potassium ion content was 0.224% by weight, and the silicon content was 1.18% by weight.

Tetraethyl orthosilicate (Si (OC ₂ H ₅ ) ₄ ) was placed in a stainless steel autoclave having a capacity of 1.5 liters.
100 g, kettle liquid 350 obtained by distillation of the above filtrate
g, 85 wt% potassium hydroxide 0.66 g and water 99
g, and stirred vigorously for 120 minutes. Molar ratio of water, tetra-n-propylammonium ion, hydroxide ion, carboxylate ion (total of formate ion, acetate ion and propionate ion), carbonate ion and potassium ion to silicon in the obtained mixed liquid. Are 36, 0.25, 0.26, 0.0002,
It was 0.0025 and 0.048.

Hydrothermal synthesis and the subsequent operations were performed on this mixed solution in the same manner as in Example 1. As a result, the conversion of cyclohexanone oxime was 99.5% and the selectivity of ε-caprolactam was 96.8%.

Comparative Example 1 In a stainless steel autoclave having a capacity of 1.5 liter,
Tetraethyl orthosilicate (Si (OC ₂ H ₅ ) ₄ ) 115 g, 3
8.8 wt% tetra-n-propylammonium hydroxide aqueous solution (total content of formate ion, acetate ion and propionate ion: 0.045 wt%, carbonate ion content: 0.055 wt%, containing potassium ion Amount: 0.
52 wt%) 144 g, acetic acid 16.58 g, tetra-n-propylammonium bromide 5.9 g, 85 wt% potassium hydroxide 0.488 g and water 273 g
Stir vigorously for 0 minutes. Water, tetra-n-propylammonium ion, with respect to silicon in the obtained mixed liquid,
The molar ratio of hydroxide ion, carboxylate ion (total of formate ion, acetate ion and propionate ion), carbonate ion and potassium ion is 36, respectively.
0.54, 0.51, 0.5, 0.002 and 0.0
It was 48.

Hydrothermal synthesis and subsequent operations were performed on this mixed solution in the same manner as in Example 1. As a result, the obtained crystal was not a pentasil-type zeolite, but the conversion of cyclohexanone oxime was 0.6% and the selectivity of ε-caprolactam was 29.7%.

[0050]

According to the present invention, a pentasil-type zeolite having excellent catalytic activity and reaction selectivity can be produced with good reproducibility. Then, by using the obtained pentasil-type zeolite as a catalyst and subjecting cyclohexanone oxime to a Beckmann rearrangement reaction in a gas phase, ε-caprolactam can be produced in high yield with good reproducibility.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroshi Ichihashi             Sumitomo Chemical 5-1, Soukai-cho, Niihama-shi, Ehime             Industry Co., Ltd. F-term (reference) 4C034 DE03                 4G069 AA08 BA07A BA07B BD01A                       BD01B BD06A BD06B BE08C                       BE17C CB41 CB59 ZA10A                       ZA10B ZB03 ZB05 ZB08                       ZD01                 4G073 BA04 BA05 BB05 BB48 BB66                       BB69 CZ12 FB01 FB19 FB42                       FC01 FD05 FD23 UA01                 4H039 CA42 CJ90

Claims (5)

[Claims] (1) A silicon compound, water and tetra-n-propylammonium hydroxide are mixed to give a hydroxide ion to silicon molar ratio of 0.1 to 0.6, and a carbon to silicon atom. The molar ratio of acid ions is 0.3
The step of preparing a mixed solution which is the following: (2): the step of subjecting the mixed solution prepared in the step (1) to a hydrothermal synthesis reaction, (3): crystallized from the reaction mixture obtained in the step (2) (4): a step of firing the crystal separated in step (3),
And (5): a process for producing a pentasil-type zeolite, which comprises a step of subjecting the crystal calcined in step (4) to a contact treatment with an aqueous solution containing ammonia and / or an ammonium salt. 2. The production method according to claim 1, wherein the silicon compound used in the step (1) is tetraalkyl orthosilicate. 3. The step (1) further comprises mixing sodium hydroxide and / or potassium hydroxide.
Or the manufacturing method according to 2. 4. The method according to claim 1, wherein at least a part of the residual liquid after separating the crystals from the reaction mixture obtained in step (2) is circulated in step (1). . (1) (1): A silicon compound, water and tetra-n-propylammonium hydroxide are mixed, and the molar ratio of hydroxide ion to silicon is 0.1 to 0.6, and the carboxyl group to silicon is The molar ratio of acid ions is 0.3
The step of preparing a mixed solution which is the following: (2): the step of subjecting the mixed solution prepared in the step (1) to a hydrothermal synthesis reaction, (3): crystallized from the reaction mixture obtained in the step (2) (4): a step of firing the crystal separated in step (3),
And (5): the pentasil-type zeolite obtained by a series of steps of contact-treating the crystal calcined in step (4) with an aqueous solution containing ammonia and / or ammonium salt is used as a catalyst, and the presence of this catalyst Below, a method for producing ε-caprolactam, which comprises subjecting cyclohexanone oxime to a Beckmann rearrangement reaction in a gas phase.