JPH0912539A - Production of epsilon-caprolactam - Google Patents

Abstract

PURPOSE: To produce ε-caprolactam in improved ε-caprolactam selectivity and catalytic life, etc., on an industrial scale at a low cost by using a catalyst consisting of a pentasil-type zeolite supporting a transition metal. CONSTITUTION: ε-Caprolactam is produced by contacting cyclohexanone oxime with a zeolite catalyst in vapor phase. The zeolite catalyst is a pentasil-type zeolite supporting at least one kind of transition metal selected from platinum, palladium, rhodium and ruthenium.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing ε-caprolactam, more specifically, a pentasil type in which cyclohexanone oxime is supported in a gas phase on at least one transition metal selected from platinum, palladium, rhodium and ruthenium. The present invention relates to a method for producing ε-caprolactam by bringing it into contact with a zeolite catalyst.

[0002]

PRIOR ART, PROBLEMS TO BE SOLVED BY THE INVENTION ε-caprolactam is a basic chemical raw material known as a raw material for nylon, etc., and various production methods by contacting cyclohexanone oxime with a zeolite catalyst in a gas phase are also proposed. Has been done. For example, as a zeolite catalyst, silicon /
A method using a pentasil type zeolite having an aluminum ratio of 40 to 60 (JP-A-57-139062) and a method using a pentasil-type zeolite having a silicon / metal atomic ratio of 500 or more (JP-A-62-123167). Japanese Examined Patent Publication No. 4-40342) is known. Further, the presence of lower alcohol in the reaction system, the selectivity of ε-caprolactam,
A method for improving the catalyst life etc. has also been proposed (JP-A-2-
(275850 publication). However, none of the known methods is completely satisfactory in terms of catalyst life, and improvement in this point has been desired.

[0003]

In view of such circumstances, the present inventor has conducted diligent studies to find out a more excellent method for producing ε-caprolactam, and as a result, selected from platinum, palladium, rhodium and ruthenium as a catalyst. It was found that if a specific zeolite catalyst called pentasil-type zeolite supporting at least one kind of transition metal is used, not only the catalyst life can be improved but also ε-caprolactam can be produced with high selectivity, and further various studies are conducted. To complete the present invention.

That is, in the present invention, in producing ε-caprolactam by bringing cyclohexanone oxime into contact with a zeolite catalyst in a gas phase, the zeolite catalyst is
An industrially excellent ε-characterized by using a pentasil-type zeolite carrying at least one transition metal selected from platinum, palladium, rhodium and ruthenium.
A method for producing caprolactam is provided.

Hereinafter, the present invention will be described in detail. The present invention is characterized in that a pentasil-type zeolite supporting at least one transition metal selected from platinum, palladium, rhodium and ruthenium is used as a catalyst. The pentasil-type zeolite is silicon / metal. Those having an atomic ratio of 100 or more are preferably used. Here, as the metal, for example, Al, Ga, Fe, B, Z
n, Cr, Be, Co, La, Ge, Ti, Zr, Hf, V, Ni, Sb, B
Examples thereof include i, Cu, Nb, and In, among which In is preferable. The pentasil-type zeolite can be produced according to a known method, and the silicon / metal atomic ratio can be determined by a usual analytical means such as an atomic absorption method and a fluorescent X-ray method.

In supporting the transition metal on the pentasil-type zeolite, for example, the pentasil-type zeolite as described above is immersed in a solution in which a transition metal compound is dissolved, filtered, dried, and optionally reduced with hydrogen gas. It can be produced by treatment. Here, as the transition metal compound, for example, platinum chloride (IV), chloroplatinic acid (I
V), tetraammine platinum (II), palladium chloride (II), ruthenium chloride (IV), chlorides such as rhodium (III) chloride, palladium nitrate (II), nitrates such as ruthenium nitrate (III),
Examples thereof include carbonyl compounds such as tricarbonyl rhodium (0), organometallic compounds such as platinum acetylacetonate (II) and palladium (II) acetate. The amount of transition metal supported is 0.01 to 2% by weight, preferably 0.1 to 1% by weight, based on the pentasil-type zeolite.

The present invention is characterized by using the above-mentioned transition metal-supported pentasil-type zeolite. However, by carrying out the reaction in the presence of a lower alcohol, an inert gas, etc., the efficiency can be improved. The reaction can be allowed to proceed. Examples of such lower alcohols include linear or branched carbon atoms of 1 such as methanol, ethanol, n-propanol, i-propanol and butanol.
~ 4 alcohols. These lower alcohols may be used alone or in combination of two or more, but are preferably methanol. Further, examples of the inert gas include carbon dioxide, hydrogen, nitrogen and the like, but carbon dioxide is preferable.

In carrying out the present invention, a fixed bed system, a fluidized bed system or the like is usually adopted. The raw material cyclohexanone oxime is brought into contact with the catalyst layer in a gas state,
When a lower alcohol, an inert gas or the like is used for the contact, a mixture of these and cyclohexanone oxime may be supplied to the catalyst layer or may be supplied separately. In the case of the fixed bed system, it is preferable to allow them to pass through the catalyst layer in a sufficiently mixed state.

When a lower alcohol is present in the reaction system, the amount thereof is usually relative to cyclohexanone oxime.
It is about 0.1 to 20 times by weight, preferably about 0.3 to 15 times by weight. When an inert gas is present, the amount thereof is usually about 0.05 to 10 mol times, preferably about 0.2 to 5 mol times, relative to cyclohexanone oxime.

The reaction temperature is usually 300 to 450 ° C, more preferably 300 to 400 ° C. If the temperature is lower than 300 ° C, the reaction rate is not sufficient, and if the temperature exceeds 450 ° C, the selectivity of ε-caprolactam tends to decrease due to the thermal decomposition of cyclohexanone oxime. The space velocity of cyclohexanone oxime is WHSV (feed rate per catalyst weight), and is usually 0.1 to 20 hr ^-1 , preferably 0.2 to 10 hr ^-1 ,
It is more preferably 0.5 to 10 hr ^-1 .

Thus, ε-caprolactam is produced, which is separated from the reaction mass by a conventional method. For example, the reaction product gas can be cooled to be condensed and then separated by extraction, distillation or crystallization. When lower alcohols, carbon dioxide, etc. are present, these can be recovered from the reaction mass and reused. Further, a catalyst whose activity has been reduced by long-term use can easily restore its original performance by, for example, firing in a gas stream containing molecular oxygen, and can be used repeatedly.

[0012]

According to the present invention, by using a pentasil-type zeolite carrying at least one transition metal selected from platinum, palladium, rhodium and ruthenium as a catalyst, the selectivity of ε-caprolactam and the catalyst life are obtained. Etc. can be improved, and ε-caprolactam can be produced industrially advantageously.

[0013]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

Reference Example 1 Tetraethyl orthosilicate was added to a 1.25 l autoclave.
100g, 10% tetra-n-propylammonium hydroxide water
217.5 g of the solution was added and vigorously stirred for 30 minutes. Then this
0.0689 g of indium (III) chloride tetrahydrate and 214 g
Add a solution of ethylene glycol and stir for 30 minutes.
Then, while maintaining the internal temperature at 105 ° C for 120 hours at 400 rpm.
Hydrothermal synthesis was carried out with continuous stirring. During this time, the internal pressure is 1.8 kg /
cm ^Two ・ G has been reached. The white solid produced was filtered off and the filtrate
Wash with ion-exchanged water until pH is around 7, dry, air
20g of powder was obtained by calcining under circulation at 540 ℃ for 6 hours.
White crystals were obtained. The crystals were analyzed by powder X-ray diffraction
As a result, it was identified as a pentasil-type zeolite. Another atom
Elemental analysis by absorption spectroscopy showed Si / In atomic ratio of 500
Met. 20 g of this crystal was added to a 5% ammonium chloride aqueous solution.
After adding 200 g and performing ion exchange treatment at 60 ° C for 1 hour,
It was filtered off. After performing this ion exchange treatment 4 times, chlorine
It was washed with ion-exchanged water until no ions were detected.
Then, after drying the crystals, under a nitrogen gas stream at 540 ° C for 5 hours.
20g of indium silicate was obtained by firing during
Was.

20 g of water and tetraammine platinum (II) chloride
1g of indium silicate in a solution consisting of 0.0086g
Was added, and the mixture was stirred at 90 ° C for 5 hours, filtered, and then at 110 ° C for 24 hours.
Dried for hours. Next, platinum was carried by carrying out a reduction treatment at 450 ° C. for 5 hours in a hydrogen gas stream. The amount of platinum supported was 0.5% by weight based on indium silicate. The platinum-supported indium silicate was pelletized using an IR tableting machine, then crushed and sieved to a particle size of 32 to 48 mesh to obtain a catalyst A.

Reference Example 2 Reference Example 1 except that platinum is not supported in Reference Example 1.
Catalyst B was obtained by carrying out in accordance with

Reference Example 3 The procedure of Reference Example 1 was repeated except that 0.0083 g of palladium (II) chloride (PdCl ₂ ) was used in place of tetraammineplatinum (II) chloride. P
A catalyst C carrying d was obtained.

Reference Example 4 The procedure of Reference Example 1 was repeated except that 0.0103 g of rhodium (II) chloride (RhCl ₂ ) was used in place of the tetramine platinum (II) chloride. A catalyst D carrying Rh was obtained.

Reference Example 5 In Reference Example 1, instead of tetramine platinum (II) chloride, ruthenium (IV) chloride pentahydrate (RuCl ₄ ) 5H ₂ O 0.0165 g
By following the procedure of Reference Example 1 except for using 0.
A catalyst E having 5% by weight of Ru supported thereon was obtained.

Example 1 0.15 g of catalyst A was filled in a stainless steel reaction tube having an inner diameter of 3 mm, and carbon dioxide was supplied at 35 ml / min to the reaction tube at 350 ml.
It was treated at 60 ° C for 60 minutes. Then, a mixture of cyclohexanone oxime and n-propyl alcohol (molar ratio 1:14) was fed at 2.95 g / hr while reacting with carbon dioxide at 350 ° C. at the same rate as above to react. Space velocity WH
The SV was 2.3 hr ^-1 , the reaction was continued for 10 hours, and the reaction mass was collected every hour in ice-cooled toluene and analyzed by gas chromatography. The results are shown in Table 1. In addition, WHS
The reaction rates of V and cyclohexane, and the selectivity of ε-caprolactam were calculated by the following equations. WHSV (hr ^-1 ) = cyclohexanone oxime supply rate (kg / hr) / catalyst weight (kg) Reaction rate (%) = ((XY) / X) x 100 Selectivity (%) = (Z / (XY)) × 100 X = supplied cyclohexanone oxime (mol), Y = unreacted cyclohexanone oxime (mo)
l), Z = generated ε-caprolactam (mol)

Table 1 Elapsed time (hr) Reaction rate (% ) Selectivity (% ) 0.5 99.8 93.9 1 99.4 95.3 2.5 98.6 95.4 4 98.2 96.7 7 96.0 95.0 10 98.1 95.3

Example 2 The procedure of Example 1 was repeated except that a mixture of cyclohexanone oxime and methanol (molar ratio 1:14) was fed at 3.0 g / hr (space velocity WHSV was 4.0 hr ^-1 ). The test was carried out in accordance with the above, and the results are shown in Table 2. Table 2 Elapsed time (hr) Response rate (% ) Selectivity rate (% ) 0.5 99.8 94.6 1 99.8 95.2 2.5 99.8 95.4 4 99.9 95.2 7 99.9 95.1 10 99.9 96.0

Example 3 The procedure of Example 1 was repeated except that hydrogen was used instead of carbon dioxide, and the results are shown in Table 3. Table 3 Elapsed time (hr) Response rate (% ) Selectivity (% ) 0.5 99.7 91.2 1 98.7 90.7 2.5 97.2 92.9 4 96.3 93.7 7 92.2 94.5 10 89.9 94.9

Example 4 The procedure of Example 1 was repeated, except that nitrogen was used instead of carbon dioxide, and the results are shown in Table 4. Table 4 Elapsed time (hr) Response rate (% ) Selectivity rate (% ) 0.5 98.6 93.8 1 97.7 94.7 2.5 96.9 95.2 4 95.9 95.4 7 92.2 95.8 10 86.7 95.6

Example 5 The procedure of Example 1 was repeated except that the catalyst A was replaced by the catalyst C, and the results are shown in Table 5. Table 5 Elapsed time (hr) Response rate (% ) Selectivity rate (% ) 0.5 99.7 93.3 1 98.7 95.3 2.5 96.0 95.6 4 93.7 95.8 7 90.1 95.1 10 86.4 96.3

Example 6 The procedure of Example 1 was repeated except that the catalyst A was replaced by the catalyst D, and the results are shown in Table 6. Table 6 Elapsed time (hr) Response rate (% ) Selectivity rate (% ) 0.5 98.7 93.9 1 97.2 94.9 2.5 93.8 95.4 4 90.4 95.3 7 88.4 95.0 10 86.1 95.5

Example 7 A mixture of Example 1 except that the catalyst A was used instead of the catalyst A, and the mixture consisted of cyclohexanone oxime and methanol.
(Molar ratio 1:14) at 3.0 g / hr (space velocity WHSV
Was carried out in accordance with Example 1 except for 4.0 hr ⁻¹ ), and the results are shown in Table 7. Table 7 Elapsed time (hr) Response rate (% ) Selectivity rate (% ) 0.5 99.8 95.6 1 99.5 95.6 2.5 99.3 95.9 4 99.4 96.1 7 99.0 96.0 10 97.5 96.2

Comparative Example 1 The procedure of Example 1 was repeated except that the catalyst B was used in place of the catalyst A, and the results are shown in Table 8. Table 8 Elapsed time (hr) Response rate (% ) Selectivity rate (% ) 0.5 97.6 95.1 1 95.7 95.5 2.5 91.5 95.2 4 89.8 95.6 7 84.4 96.4 10 82.5 95.5

Claims (6)

[Claims] 1. In producing ε-caprolactam by contacting cyclohexanone oxime with a zeolite catalyst in a gas phase, platinum, palladium, and
A method for producing ε-caprolactam, which comprises using a pentasil-type zeolite supporting at least one transition metal selected from rhodium and ruthenium. 2. The production method according to claim 1, which is carried out in the presence of a lower alcohol. 3. The method according to claim 2, wherein the lower alcohol is at least one selected from methanol, ethanol and propanol. 4. The method according to any one of claims 1 to 3, which is carried out in the presence of an inert gas. 5. The method according to claim 4, wherein the inert gas is at least one selected from carbon dioxide, hydrogen and nitrogen. 6. The pentasil-type zeolite having a silicon / metal atomic ratio of 100 or more.
6. The production method according to any one of claims 1 to 5.