JPH0892213A - Production of carbazole - Google Patents

Abstract

PURPOSE: To economically obtain carbazole in an industrially advantageous way. CONSTITUTION: The objective carbazole is obtained by cyclodehydrogenation of diphenylamine by using the following catalyst: carrying 0.1-10wt.% of Pt on a formed carrier in a highly dispersed fashion and having a CO adsorption of >=9.85×10<-4> mol/g-Pt, or carrying 0.1-20wt.% of Pt on a carbon powder carrier in a highly dispersed fashion and having a CO adsorption of >=25.1×10<-4> mol/g- Pt.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a carbazole by dehydrocyclizing diphenylamine. The present invention also relates to a method for producing high-purity carbazole from crude carbazole.

[0002]

BACKGROUND OF THE INVENTION Carbazole is a useful material as a raw material for dyes, pigments and the like. Carbazole contains about 0.1 to 1% in coal tar, and can usually be produced by separating and purifying from coal tar. A conventionally known method for producing carbazole is, for example, a method in which a fraction having a boiling point of 300 to 400 ° C. obtained by distilling coal tar is cooled and crystallized, and the obtained solid content is subjected to solvent extraction. However, this solvent extraction method is not an economically useful manufacturing method because it has problems such as complicated steps and difficulty in obtaining high-purity carbazole in high yield.

Similarly, a fraction having a boiling point of 300 to 400 ° C. obtained by similarly distilling coal tar is crystallized by cooling, and a monohydric alcohol is added to the obtained solid content to carry out azeotropic distillation to carry out carbazole. A method of recovering the above has also been proposed (US Pat. No. 2,675,345). However, even with this method, high-purity carbazole cannot be efficiently obtained, and recovery of the azeotropic agent is not easy, so it cannot be said to be an economically useful manufacturing method. All of the above methods are methods for recovering carbazole from coal tar by separation and purification.
It is not economically useful to recover carbazole containing only about%.

The present inventors considered to produce carbazole from an inexpensive raw material, for example, diphenylamine, by chemical synthesis in order to industrially produce it at low cost. As a method for producing carbazole by chemical synthesis from diphenylamine, synthesis by a dehydrocyclization reaction of diphenylamine using a catalyst in which platinum is supported on silica, alumina or silica / alumina has also been reported (Japanese Patent Publication No. Sho-3).
7-9234). However, this method requires the weight hourly space velocity to be 0.3 or less, and
Since many by-products such as benzene and aniline are produced and the yield is low, it cannot be said to be an efficient production method. Here, the weight hourly space velocity is the ratio of diphenylamine (parts by weight) introduced into the reaction part per hour to the catalyst (parts by weight).

The above-mentioned known technique is a method by chemical synthesis as in the present invention, but is different from the present invention described in detail below because the components of the catalyst are different. That is, the conventionally known method for producing carbazole is
None of them are completely satisfactory in terms of establishing an economically useful manufacturing method when they are industrially carried out.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing carbazole which is economically useful when it is industrially carried out. That is, an object of the present invention is to provide a method for producing carbazole by dehydrocyclizing inexpensive diphenylamine by a novel production method using a new catalyst. Another object of the present invention is to provide a method for recovering carbazole in good yield by extracting or recrystallizing diphenylamine from a reaction product (crude carbazole) obtained by dehydrocyclization using an inexpensive solvent. Especially.

[0007]

Means for Solving the Problems As a result of research for solving the above problems, the present inventor has found that by using a platinum-supported catalyst in which platinum is highly dispersed and supported on a specific carrier, a dehydrogenation ring of diphenylamine can be obtained. The present invention has been completed by finding that the chemical reaction proceeds efficiently. According to the present invention, 0.1 to 10 wt% of platinum is supported on a molded carrier, and highly dispersed supported platinum having a CO adsorption amount of 9.85 × 10 ⁻⁴ mol / g-platinum or more. It is a method for producing carbazole by dehydrocyclizing diphenylamine using a supported catalyst.

According to the present invention, 0.1 to 20 wt% of platinum is supported on the carbon powder carrier, and the amount of CO adsorbed is 25.1 × 10 ^-4 mol / g-platinum or more. Is a method for producing carbazole by dehydrocyclizing diphenylamine using a highly supported platinum-supported catalyst. Furthermore, the present invention further comprises, in addition to the above-mentioned highly supported platinum-supported catalyst, a catalyst in which 0.01 to 10 wt% of sulfur is supported on the carrier, and 0.01 to 10 wt% of the carrier.
% Of an alkali metal such as sodium or potassium is used to produce a carbazole by dehydrocyclizing diphenylamine.

The highly dispersed and supported platinum-supported catalyst used in the present invention is a platinum-supported catalyst in which a specific amount of platinum is supported on a specific carrier and the supported platinum is in a highly dispersed state. According to the knowledge of the present inventor, the platinum-supported catalyst contains C
It has the property of selectively chemisorbing O on the platinum surface. In the case of platinum-supported catalysts with the same carrier and the same amount of supported platinum,
The higher the dispersed state of the supported platinum, the higher the CO adsorption amount. Therefore, the dispersion state of the supported platinum can be examined from the amount of CO adsorbed.

A molded carrier or carbon powder is used as the carrier of the highly dispersed and supported platinum catalyst used in the present invention. As the molded carrier, a molded body of silica, alumina, silica / alumina or the like can be used. The molded carrier used in the present invention preferably has an average particle size of 100 μm or more, particularly 500 to 5000 μm.

As the powder carrier, use is made of carbonaceous powder or a molded product thereof, specifically carbon black, coke powder, activated carbon powder, carbide of mesocarbon microbeads, etc., and granulated or molded products thereof. You can The carbon powder carrier used in the present invention preferably has an average particle size of 100 μm or less, particularly 1 to 50 μm.

In the present invention, a highly dispersed supported platinum-supported catalyst, that is, a platinum-supported catalyst having a higher CO adsorption amount than the conventional platinum-supported catalyst is used as a catalyst for the dehydrogenative cyclization reaction of diphenylamine. Specifically, when the carrier is a molded carrier, the amount of platinum supported is 0.1 to the carrier.
10 wt% and CO adsorption amount is 9.85 × 10 ⁻⁴ m
ol / g-platinum or more, preferably 10.7 × 10 ^-4 ~
A platinum-supported catalyst that is 4.48 × 10 ⁻⁴ mol / g-platinum is used. When the carrier is a carbon powder carrier, the amount of platinum supported is 0.1 to 20 wt% with respect to the carrier, and the CO adsorption amount is 25.1 × 10 ⁻⁴ mol / g-platinum or more, preferably 26.0 x 10 ^{-4 to} 53.7 x 10 ^-4 m
A platinum-supported catalyst that is ol / g-platinum is used.

The method for preparing the catalyst used in the present invention, that is, the method for supporting platinum on the carrier is not particularly limited. For example, there is a method in which a platinum compound is adsorbed on a carrier and then reduced. As the platinum compound, chloroplatinic acid (H ₂ PtC
l ₆ ) can be used. As a method of supporting chloroplatinic acid on a carrier, there is a method of bringing the carrier and chloroplatinic acid into contact with each other and heating them under alkaline conditions. Foam water hydrazine can be used as a reducing agent for the reduction of chloroplatinic acid adsorbed on the carrier.

In the present invention, the apparatus used for the dehydrogenative cyclization reaction of diphenylamine may be either a batch type or a continuous type. The dehydrogenative cyclization reaction of diphenylamine in the present invention is preferably carried out in a hydrogen atmosphere or an inert gas atmosphere under a reaction condition of a reaction temperature of 300 to 650 ° C. and a reaction pressure of 30 kg / cm ² G or less. The method for producing carbazole by the dehydrocyclization reaction of diphenylamine is a competitive reaction in which the formation of carbazole and the formation of benzene and aniline by the hydrogenolysis reaction occur, and the reaction temperature is 650 ° C.
In the above cases and when the reaction pressure is 30 kg / cm ² G or more, the production of benzene and aniline increases. When the reaction temperature is 300 ° C or lower, carbazole is hardly produced.

From the viewpoint of yield, the reaction atmosphere is generally preferably an inert gas atmosphere. However, when it is desired to suppress the carbon deterioration of the catalyst and prolong the life of the catalyst, particularly in the case of continuous operation, it is preferable to use a hydrogen atmosphere. In the present invention, the weight hourly space velocity in the case where the dehydrogenative cyclization reaction of diphenylamine is carried out in a continuous reaction apparatus is 0.4 or more, preferably 0.
It is good to set it to about 8 to 1.2.

In the present invention, the reaction product (crude carbazole) obtained by the dehydrogenation reaction of diphenylamine is
High-purity carbazole can be produced by extraction or recrystallization using an alcohol having 1 to 5 carbon atoms. This method is effective for producing carbazole having a purity of 95% or more, particularly 98% or more.

[0017]

When the dehydrogenative cyclization of diphenylamine is carried out using a metal-supported catalyst, diphenylamine generates active hydrogen on the catalyst carrier and is converted into carbazole. The generated active hydrogen is adsorbed on the catalyst surface and moves on the carrier to promote hydrogenation or hydrogenolysis of the compounds existing on the surface of the supported metal, so that diphenylamine is converted to benzene or aniline. I will end up.

The platinum-supported catalyst used in the present invention has the function of migrating the active hydrogen generated on the carrier on the carrier as well as the conventional metal-supported catalyst by the action of the highly dispersed and supported platinum, and at the same time, the active hydrogen of platinum is supported on the carrier. It has a function of converting to hydrogen molecules on the surface and desorbing it from the catalyst surface (called reverse spillover phenomenon). In the present invention, it is considered that this reverse spillover phenomenon suppresses the production of benzene or aniline, which is a side reaction. The present invention has been completed on the basis of the finding that a platinum-supported catalyst supported highly dispersed as described above is effective as a catalyst having such a reverse spillover phenomenon.

The catalyst of the present invention which further supports sulfur on the highly supported platinum-supported catalyst can suppress the adsorption of active hydrogen on the surface of the supported metal (platinum), so that the catalyst further accelerates the reverse spillover phenomenon. Can be. Further, the advantage of the catalyst supporting an alkali metal such as sodium or potassium in the highly dispersed supported platinum-supported catalyst of the present invention is that decomposition occurs at the nitrogen atom when the nitrogen atom of diphenylamine is adsorbed on the catalyst surface, In contrast to the occurrence of many side reactions, the catalyst surface is kept negative so that it is in the opposite state, that is, the benzene ring is adsorbed and the dehydrocyclization is promoted.

[0020]

INDUSTRIAL APPLICABILITY According to the present invention, carbazole can be economically produced in high yield by dehydrocyclization of industrially inexpensive diphenylamine. Further, the carbazole (crude carbazole) produced by the present invention has 1 to 1 carbon atoms.
High-purity carbazole can be economically obtained by extraction or recrystallization with the alcohol of 5.

[0021]

【Example】

[Preparation of platinum supported catalyst] 5% platinum / carbon powder catalyst (highly dispersed platinum product) 16 g of 10% aqueous sodium hydroxide solution in 266 ml of pure water
20. After charging, the carbon powder carrier [average particle diameter 25 μm] 20.
0 g was added and stirred. Next, chloroplatinic acid (H ₂ PtC
l ₆ ) was dissolved in 2.5 g of pure water and added dropwise over 1 hour. Then, the temperature is raised to 85 to 90 ° C. and kept for 30 minutes,
Subsequently, bubble water hydrazine (H ₂ NNH ₂ · H ₂ O) was added to the mixture.
64 g was added, and the catalyst was further reduced by holding it for 30 minutes. After completion of the reduction, the catalyst was cooled, filtered, and washed with pure hot water until chlorine was not detected in the filtrate. Then, it was air-dried to obtain a catalyst. A dry weight of 20 g of catalyst was obtained, and the amount of platinum supported was 5 wt% with respect to the carbon powder carrier.

Sulfur-supported platinum / carbon powder catalyst (highly dispersed platinum)
Goods) was added 20g were suspended 5% platinum / carbon powder catalyst prepared in pure water 150ml in the manner described (highly dispersed product) in terms of dry weight, followed by stirring. Next, add 15 ml of pure water to sodium sulfide (N
0.53 g of a ₂ S) was dissolved and added to the above slurry. Then, after stirring and holding for 1 hour, the slurry was filtered and air-dried. The amount of sulfur supported on the obtained catalyst was 0.8 wt% with respect to the carbon powder carrier.

Sodium supported platinum / carbon powder catalyst (platinum
Highly dispersed product) 5% platinum / carbon powder catalyst prepared in pure water 150ml in the manner described (highly dispersed product) was added 20g on a dry weight basis were suspended, followed by stirring. Next, 2.31 g of sodium hydroxide was dissolved in 15 ml of pure water and added to the above slurry. Then, after stirring and holding for 1 hour, the slurry was filtered and air-dried. The amount of sodium supported on the obtained catalyst was 1.0 wt% with respect to the carbon powder carrier.

Preparation Method of 1% Platinum / Carbon Bead Catalyst (White
Gold highly dispersed product) 0.5 ml of chloroplatinic acid (H ₂ PtCl ₆ ) was added to 40 ml of pure water.
Dissolve 2g, carbon bead carrier [average particle size 600μm]
After the addition of 20 g, the color of the platinum solution disappeared due to adsorption of platinum, 3.3 g of 10% sodium hydroxide was added, and the temperature was further raised to 90 ° C. or higher to completely adsorb platinum. next,
After adding 0.13 g of foam water hydrazine, the mixture was kept for 30 minutes to reduce the catalyst. The catalyst was separated by filtration, washed with pure warm water until chlorine was not detected in the washing solution, and dried at 100 ° C. The obtained catalyst was 20 g, and the amount of platinum supported was 1.0 wt% with respect to the carbon bead carrier.

Preparation Method of 5% Platinum / Carbon Bead Catalyst (White
Gold high-dispersion product) Chloroplatinic acid (H ₂ PtCl ₆ ) was added to 2.9 in 40 ml of pure water.
Dissolve 7 g, carbon bead carrier [average particle size 600 μm]
After the addition of 20 g, the color of the platinum solution disappeared due to the adsorption of platinum, 19.0 g of 10% sodium hydroxide was added, and the temperature was further raised to 90 ° C. or higher to completely adsorb platinum. Next, 0.74 g of foam water hydrazine was added, and the mixture was kept for 30 minutes to reduce the catalyst. Then, after the catalyst was filtered off, it was washed with pure warm water until chlorine was not detected in the washing solution, and then 10
Drying was performed at 0 ° C. 20 g of catalyst was obtained, and the supported amount of platinum was 5 wt% with respect to the carbon bead carrier.

[Method of Measuring CO Adsorption] The platinum catalyst is CO
Has the property of adsorbing. Here, CO is chemisorbed only on the platinum surface in the catalyst. In the case of a catalyst carrying the same amount of platinum, the amount of CO adsorbed is large if the platinum is highly dispersed (finely dispersed), and the CO is adsorbed if the platinum is lowly dispersed (largely dispersed).
The amount of adsorption decreases. Therefore, measuring the CO adsorption amount is an index for examining the dispersion state of platinum particles. The measurement can be performed by a general glass vacuum adsorption device or a flow type pulse adsorption device. The CO adsorption amount of each of the above-mentioned catalysts, which was measured by the flow type pulse adsorption device, was as follows.

Catalyst CO adsorption amount (mol / g-platinum) 5% platinum / carbon powder 3.13 × 10 ⁻³ 1% platinum / carbon beads 2.24 × 10 ⁻³ 5% platinum / carbon beads 3.58 × 10 ⁻³ [Production of carbazole] Example 1 A 100 cc shaking type stainless steel autoclave was used.
1.0 g of 1% platinum / carbon bead catalyst finely pulverized in an agate mortar and 10 g of diphenylamine were charged, the autoclave was purged with nitrogen, and then the temperature was raised to 450 ° C. to start the reaction. The reaction time required 2 hours to reach 450 ° C, and the reaction was continued for another 2 hours after reaching 450 ° C. The pressure after the reaction was 16 kg / cm ² G. As a result of analyzing the obtained reaction liquid, the yield of carbazole was 54.9%, and the selectivity was 77.5%.

The yield and selectivity of carbazole referred to in the present specification are calculated according to the following formulas: [Yield] (%) = [number of moles of carbazole obtained after the reaction] / [raw material diphenylamine before the reaction] Number of moles] ×
100; [selectivity] (%) = [weight of carbazole obtained after reaction] / [weight of reacted diphenylamine] × 100 Example 2 Implemented except that 0.05 g of 5% platinum / carbon powder was used as a catalyst. The reaction was carried out under the same conditions as in Example 1. The pressure after the reaction was 17 kg / cm ² G. As a result of analyzing the reaction product, the yield of carbazole was 70.4% and the selectivity was 8
It was 1.8%.

Example 3 The reaction was carried out under the same conditions as in Example 1 except that 0.20 g of 5% platinum / carbon powder supporting 0.8% of sulfur was used as the catalyst. As a result of analyzing the reaction product, the yield of carbazole was 42.9%, and the selectivity was 92.3%.

Example 4 The reaction was carried out under the same conditions as in Example 1 except that 0.20 g of 5% platinum / carbon powder supporting 1% sodium was used as the catalyst. As a result of analyzing the reaction product, the yield of carbazole was 59.9%, and the selectivity was 87.1%.

Example 5 14 g of 1% platinum / carbon bead catalyst was charged into a reaction tube of a fixed bed flow reactor, and a normal pressure reaction was carried out at 450 ° C. 14 g of the raw material diphenylamine was supplied per hour while flowing 40 cc of hydrogen per minute. The yield of carbazole was 43.6%, and the selectivity was 97.7%.

Example 6 The reaction was carried out under the same conditions as in Example 5 except that 7 g of the raw material diphenylamine was supplied every hour. The yield of carbazole was 80.4% and the selectivity was 95.3%.

Example 7 The reaction was carried out under the same conditions as in Example 5 except that the catalyst was 5% platinum / carbon beads. The yield of carbazole is 67.
5% and the selectivity was 75.4%.

Example 8 To 100 parts of the reaction product (crude carbazole) obtained by the reaction of Example 5, 400 parts of isopropyl alcohol was added and stirred at reflux temperature for 1 hour. After cooling to room temperature, solid-liquid separation was performed by filtration. The obtained crystals were washed with 20 parts of methyl alcohol and filtered to remove the residual liquid. The crystal component was dried by heating to obtain 55 parts of purified carbazole. The purity of the purified carbazole was 99.2%, and the carbazole recovery rate from the raw material was 91.2%.

Comparative Example 1 The reaction was carried out under the same conditions as in Example 1 except that 0.2 g of 10% palladium / carbon was used as the catalyst. When the reaction product was analyzed, the yield of carbazole was 10.7%,
The selectivity was 71.0%. The amount of CO adsorbed on the used 10% palladium / carbon was measured to be 2.02 × 10
^{It was -3} mol / g-palladium.

Comparative Example 2 The reaction was carried out under the same conditions as in Example 5 except that 1% platinum / γ-alumina (commercially available product) was used as the catalyst. The yield of carbazole was 15.4% and the selectivity was 24.6%. The CO adsorption amount of the 1% platinum / γ-alumina catalyst used was measured and found to be 8.95 × 10 ⁻⁴ mol / g-platinum.

Comparative Example 3 As the catalyst, the loading amount of platinum was 5 w with respect to the carbon powder carrier.
t% and CO adsorption amount is 19.7 × 10 ⁻⁴ mol /
The reaction was carried out under the same conditions as in Example 1 using a platinum / carbon powder catalyst (standard product) which was g-platinum. The yield of carbazole was 10.0% and the selectivity was 51.1%.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuaki Yamada 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi, Osaka Within Osaka Gas Co., Ltd. (72) Inventor Yoshitaka Konishi, 4 Hirano-cho, Chuo-ku, Osaka-shi, Osaka 1--2, Osaka Gas Co., Ltd. (72) Inventor Hiroshi Nakamura 4-1-2, Hirano-cho, Chuo-ku, Osaka City, Osaka Prefecture (72) In-house Gas Co., Ltd. (72) Inventor, Muroi ▲ Taka ▼ Castle, Minato-ku, Tokyo 2-4-1, Hamamatsucho N Echemcat Co., Ltd. (72) Inventor Hideaki Iketani 2-4-1, Hamamatsucho Minato-ku, Tokyo N / E Chemcat Co., Ltd. (72) Inventor Tsuyoshi Hashimoto Chiba Prefecture Ichikawa City Chugoku 3-19-3

Claims (6)

[Claims] 1. On a molded carrier, 0.1 to 1 with respect to the carrier.
It is loaded with 0 wt% platinum and has a CO adsorption amount of 9.8.
A method for producing carbazole, which comprises dehydrogenative cyclization of diphenylamine using a highly dispersed supported platinum-supported catalyst of 5 × 10 ⁻⁴ mol / g-platinum or more. 2. A carbon powder carrier having a density of 0.
Dehydrocyclization of diphenylamine using a highly supported platinum-supported catalyst supporting 1 to 20 wt% of platinum and having a CO adsorption amount of 25.1 × 10 ⁻⁴ mol / g-platinum or more. A method for producing carbazole, which comprises: 3. The platinum-supported catalyst according to claim 1 or 2, further comprising a catalyst in which 0.01 to 10 wt% of sulfur is supported on the carrier, for dehydrogenative cyclization of diphenylamine. And a method for producing carbazole. 4. Dehydrogenative cyclization of diphenylamine using the platinum-supported catalyst according to claim 1 or 2 and a catalyst in which 0.01 to 10 wt% of an alkali metal is supported on the carrier. A method for producing carbazole, which is characterized. 5. A reaction temperature of 300 for dehydrocyclization of diphenylamine in a hydrogen atmosphere or an inert gas atmosphere.
To 650 ° C., a manufacturing method of a carbazole according to any one of claims 1 to 4, which comprises carrying out the following reaction conditions the reaction pressure 30kg / cm ² G. 6. A method for producing high-purity carbazole, which comprises extracting or recrystallizing the reaction product obtained by the dehydrocyclization of diphenylamine according to claim 5 with an alcohol having 1 to 5 carbon atoms. .