JP2013212499A - Palladium hydroxide-supporting solid catalyst, method for producing the same, and method for producing condensed-ring compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a solid catalyst suitably used for production of a condensed-ring compound such as carbazole or dibenzofuran.SOLUTION: A method for producing a palladium hydroxide-supporting catalyst for producing a condensed-ring compound represented by formula (2) from a compound represented by formula (1) includes the steps of: (A) supporting a palladium hydroxide on a carrier by adding an alkali solution to a mixture containing the carrier and a palladium salt and then distilling away a solvent; and (B) drying the carrier at a temperature of 150°C or lower. In the formulae, X is CH, an oxygen atom, sulfur atom, selenium atom or NR.

Description

  The present invention relates to a palladium hydroxide-supported solid catalyst, a method for producing the same, and a method for producing a condensed ring compound. More particularly, the present invention relates to a palladium hydroxide-supported solid catalyst suitable for the production of a condensed ring compound and a method for producing the same, and a method for producing a condensed ring compound such as carbazole and dibenzofuran using the solid catalyst.

Carbazole and dibenzofuran are industrially important compounds as intermediate compounds of pigments and organic electronic materials.
Carbazole and dibenzofuran are slightly contained in coal tar, and these are conventionally produced by distilling coal tar to separate a fraction having a boiling point of 300 to 400 ° C. However, carbazole and dibenzofuran are contained only about 0.1 to 1% in coal tar, and the method for producing such a low concentration target product by distillation purification is extremely low in yield and economical. I could not say. Therefore, development of the manufacturing method of condensed ring compounds, such as carbazole and dibenzofuran, with higher yield and economy is calculated | required.

As a method for producing a condensed ring compound using a catalyst, for example, Patent Document 1 and Patent Document 2 include dehydrocyclization with an inexpensive supported catalyst in which palladium or platinum is immobilized on palladium or platinum on diphenylamine or diphenyl ether. A method for synthesizing carbazole and dibenzofuran is disclosed.
However, in the case of the gas phase reaction disclosed in Patent Document 1, a high temperature of 300 ° C. or higher is required. Moreover, even in the case of the liquid phase reaction disclosed in Patent Document 2, a high temperature of 250 ° C. or higher is necessary, and the selectivity remains at about 60%.

Non-Patent Document 1 and Non-Patent Document 2 report an oxidative coupling reaction using oxygen of diphenylamine or diphenyl ether by a homogeneous Pd complex catalyst.
However, the homogeneous catalyst has a drawback that carbazole can be obtained with high selectivity under mild conditions, but the catalyst cannot be recovered and reused.
In Non-Patent Document 3, it is necessary to use a copper salt as a promoter. Although synthesis of carbazole from diphenylamine using a palladium or platinum activated carbon-supported catalyst is described in Non-Patent Document 4, a high temperature of 250 ° C. or higher is required because hydrothermal synthesis conditions are required.

JP-A-8-92213 Japanese Patent Laid-Open No. 10-59939

B. Liegault, D. Lee, M. P. Huestis, D. R. Stuart, K. Fagnou, J. Org. Chem. 2008, 73 (13), 5022-5028. T. Watanabe, S. Oishi, N. Fujii, H. Ohno, J. Org. Chem. 2009, 74, 4720-4726. V. Sridharan, M. A. Martin, J. C. Menendez, Eur. J. Org. Chem. 2009, 4614-4621. S. Matsubara, K. Asano, Y. Kajita, M. Yamamoto, Synthesis 2007, 13, 2055-2059.

  As described above, in the conventional production of a condensed ring compound such as carbazole, a solid metal catalyst has conventionally required a high temperature of 250 ° C. or more, and a homogeneous complex catalyst has been difficult to recover.

Under such circumstances, an object of the present invention is to provide a solid catalyst suitable for industrial production of condensed ring compounds such as carbazole and dibenzofuran.
Also provided is a method of producing condensed ring compounds such as carbazole and dibenzofuran with high yield and high selectivity under relatively low temperature conditions by dehydrocyclizing an inexpensive raw material using the solid catalyst. The purpose is to do.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor has obtained a solid catalyst prepared by drying on a support as palladium hydroxide, without performing heat treatment at a high temperature. The present invention has been found to show a high catalytic activity.

（式（１）中、Ｒ¹及びＲ²は、それぞれ独立して水素原子、ハロゲン原子、シアノ基、ニトロ基、ヒドロキシ基、置換基を有してもよいアルキル基、アルコキシ基、アリール基、アリールオキシ基、アシル基からなる群から選ばれる基を表し、２，２’位を除くすべての位置に結合できる。また、これらの置換基は環構造を形成していてもよい。ｍ、ｎは１〜４の整数をそれぞれ表す。
Ｘは、ＣＨ₂、酸素原子、硫黄原子、セレン原子又はＮＲ³を表し、Ｒ³は、水素原子又はアルキル基、アリール基、アシル基、アルコキシカルボニル基である。）

（式（２）中、Ｒ¹、Ｒ²、ｍ及びｎ、並びにＸはそれぞれ式（１）におけるＲ¹、Ｒ²、ｍ及びｎ、並びにＸと同義である。）
＜２＞ 工程（Ａ）において、前記担体に対する、前記パラジウム塩の重量比が、１重量％以上５０重量％以下である前記＜１＞に記載の固体触媒の製造方法。
＜３＞ 前記パラジウム塩が塩化パラジウム（ＩＩ）である前記＜１＞または＜２＞に記載の固体触媒の製造方法。
＜４＞ 前記担体が、金属酸化物である前記＜１＞から＜３＞のいずれかに記載の固体触媒の製造方法。
＜５＞ 前記担体が、ジルコニア（ＺｒＯ₂）又はチタニア（ＴｉＯ₂）である前記＜４＞記載の固体触媒の製造方法。
＜６＞ 工程（Ｂ）における乾燥温度が、７０℃以上１２０℃以下である前記＜１＞から＜５＞のいずれかに記載の固体触媒の製造方法。
＜７＞ 前記式（２）で表される縮合環化合物が、カルバゾール、フルオレン、ジベンゾチオフェン、ジベンゾセレノフェン及びジベンゾフランから選ばれる１種、またはこれらの化合物の誘導体である前記＜１＞から＜６＞のいずれかに記載の固体触媒の製造方法。
＜８＞ 前記＜１＞から＜７＞のいずれかに記載の製造方法で製造してなるパラジウム水酸化物担持固体触媒。 That is, the present invention relates to the following inventions.
<1> A method for producing a palladium hydroxide-supported catalyst for producing a condensed ring compound represented by formula (2) from a compound represented by formula (1),
(A) A step of supporting palladium hydroxide on a carrier by adding an alkali solution to a mixed solution containing the carrier and a palladium salt, and then distilling off the solvent;
(B) A method for producing a palladium hydroxide-supported solid catalyst, comprising: drying the support on which the palladium hydroxide is supported at a temperature of 150 ° C. or lower.

(In Formula (1), R ¹ and R ² are each independently a hydrogen atom, a halogen atom, a cyano group, a nitro group, a hydroxy group, an alkyl group that may have a substituent, an alkoxy group, an aryl group, Represents a group selected from the group consisting of an aryloxy group and an acyl group, and can be bonded to all positions except the 2,2 ′ position, and these substituents may form a ring structure. Represents an integer of 1 to 4, respectively.
X represents CH ₂ , an oxygen atom, a sulfur atom, a selenium atom or NR ³ , and R ³ represents a hydrogen atom or an alkyl group, an aryl group, an acyl group or an alkoxycarbonyl group. )

(Equation (2), R ^1, R ^2, m and n, and X have the same meanings as R ^1, R ^2, m and n, and X in each formula (1).)
<2> The method for producing a solid catalyst according to <1>, wherein in the step (A), a weight ratio of the palladium salt to the support is 1% by weight or more and 50% by weight or less.
<3> The method for producing a solid catalyst according to <1> or <2>, wherein the palladium salt is palladium (II) chloride.
<4> The method for producing a solid catalyst according to any one of <1> to <3>, wherein the carrier is a metal oxide.
<5> The method for producing a solid catalyst according to <4>, wherein the support is zirconia (ZrO ₂ ) or titania (TiO ₂ ).
<6> The method for producing a solid catalyst according to any one of <1> to <5>, wherein the drying temperature in the step (B) is 70 ° C. or higher and 120 ° C. or lower.
<7> The above <1> to <6, wherein the condensed ring compound represented by the formula (2) is one selected from carbazole, fluorene, dibenzothiophene, dibenzoselenophene and dibenzofuran, or a derivative of these compounds. The manufacturing method of the solid catalyst in any one of>.
<8> A palladium hydroxide-supported solid catalyst produced by the production method according to any one of <1> to <7>.

（式（１）中、Ｒ¹及びＲ²は、それぞれ独立して水素原子、ハロゲン原子、シアノ基、ニトロ基、ヒドロキシ基、置換基を有してもよいアルキル基、アルコキシ基、アリール基、アリールオキシ基、アシル基からなる群から選ばれる基を表し、２，２’位を除くすべての位置に結合できる。また、これらの置換基は環構造を形成していてもよい。ｍ、ｎは１〜４の整数をそれぞれ表す。
Ｘは、ＣＨ₂、酸素原子、硫黄原子、セレン原子又はＮＲ³を表し、Ｒ³は、水素原子又はアルキル基、アリール基、アシル基、アルコキシカルボニル基である。）

（式（２）中、Ｒ¹、Ｒ²、ｍ及びｎ、並びにＸはそれぞれ式（１）におけるＲ¹、Ｒ²、ｍ及びｎ、並びにＸと同義である。）
＜１０＞ 前記式（２）で表される縮合環化合物が、カルバゾール、フルオレン、ジベンゾチオフェン、ジベンゾセレノフェン及びジベンゾフランから選ばれる１種、またはこれらの化合物の誘導体である前記＜９＞に記載の縮合環化合物の製造方法。
＜１１＞ 式（１）で表される化合物がジフェニルアミンであり、式（２）で表される縮合環化合物がカルバゾールであって、
反応温度６０℃以上１２０℃以下、かつ、酸素分圧０．０２ＭＰａ以上１．０ＭＰａ以下の条件で合成を行う前記＜９＞に記載の縮合環化合物の製造方法。
＜１２＞ 前記パラジウム水酸化物担持固体触媒における、担体に対するパラジウム水酸化物の重量比（Ｐｄ原子換算）が、１重量％以上３０重量％以下である前記＜１１＞記載の縮合環化合物の製造方法。
＜１３＞ 前記液相の溶媒が、有機酸、又は有機酸と、１，４−ジオキサン、トルエン、酢酸エチル及びテトラヒドロフランの少なくとも１種とを含む混合溶媒であって、該混合溶媒の有機酸の割合が、５体積％以上１００体積％以下である前記＜１１＞または＜１２＞に記載の縮合環化合物の製造方法。
＜１４＞ 式（１）で表される化合物がジフェニルエーテルであり、式（２）で表される縮合環化合物が、ジベンゾフランであって、
反応温度８０℃以上１５０℃以下、酸素分圧０．１ＭＰａ以上２．０ＭＰａ以下の条件で合成を行う前記＜９＞に記載の縮合環化合物の製造方法。
＜１５＞ 前記パラジウム水酸化物担持固体触媒における、担体に対するパラジウム水酸化物の重量比（Ｐｄ原子換算）が、１５重量％以上５０重量％以下である前記＜１４＞記載の縮合環化合物の製造方法。
＜１６＞ 前記液相の溶媒が、ピバル酸を含む前記＜１４＞または＜１５＞に記載の縮合環化合物の製造方法。 <9> The palladium hydroxide-supported solid catalyst according to <8> and the compound represented by the formula (1) in a liquid phase containing Bronsted acid in an oxygen or air atmosphere at 60 ° C. or higher The manufacturing method of the condensed ring compound which makes it contact at 150 degrees C or less, and synthesize | combines the condensed ring compound represented by Formula (2).

(In Formula (1), R ¹ and R ² are each independently a hydrogen atom, a halogen atom, a cyano group, a nitro group, a hydroxy group, an alkyl group that may have a substituent, an alkoxy group, an aryl group, Represents a group selected from the group consisting of an aryloxy group and an acyl group, and can be bonded to all positions except the 2,2 ′ position, and these substituents may form a ring structure. Represents an integer of 1 to 4, respectively.
X represents CH ₂ , an oxygen atom, a sulfur atom, a selenium atom or NR ³ , and R ³ represents a hydrogen atom or an alkyl group, an aryl group, an acyl group or an alkoxycarbonyl group. )

(Equation (2), R ^1, R ^2, m and n, and X have the same meanings as R ^1, R ^2, m and n, and X in each formula (1).)
<10> The condensed ring compound represented by the formula (2) is one kind selected from carbazole, fluorene, dibenzothiophene, dibenzoselenophene, and dibenzofuran, or a derivative of these compounds. A method for producing a fused ring compound.
<11> The compound represented by the formula (1) is diphenylamine, the condensed ring compound represented by the formula (2) is carbazole,
The method for producing a condensed ring compound according to <9>, wherein the synthesis is performed under a reaction temperature of 60 ° C. or higher and 120 ° C. or lower and an oxygen partial pressure of 0.02 MPa or higher and 1.0 MPa or lower.
<12> Production of the condensed ring compound according to <11>, wherein in the palladium hydroxide-supported solid catalyst, the weight ratio of palladium hydroxide to the support (Pd atom conversion) is 1% by weight or more and 30% by weight or less. Method.
<13> The liquid phase solvent is an organic acid or a mixed solvent containing an organic acid and at least one of 1,4-dioxane, toluene, ethyl acetate, and tetrahydrofuran, The manufacturing method of the condensed ring compound as described in said <11> or <12> whose ratio is 5 volume% or more and 100 volume% or less.
<14> The compound represented by the formula (1) is diphenyl ether, the condensed ring compound represented by the formula (2) is dibenzofuran,
The method for producing a condensed ring compound according to <9>, wherein the synthesis is performed under conditions of a reaction temperature of 80 ° C. or more and 150 ° C. or less and an oxygen partial pressure of 0.1 MPa or more and 2.0 MPa or less.
<15> The production of the condensed ring compound according to <14>, wherein in the palladium hydroxide-supported solid catalyst, a weight ratio of palladium hydroxide to a support (Pd atom conversion) is 15% by weight or more and 50% by weight or less. Method.
<16> The method for producing a condensed ring compound according to <14> or <15>, wherein the liquid phase solvent contains pivalic acid.

According to the present invention, a palladium hydroxide-supported solid catalyst suitable for the synthesis of condensed ring compounds such as carbazole and dibenzofuran can be produced.
The produced palladium hydroxide-supported solid catalyst has excellent catalytic activity, and the compound represented by the formula (1) is dehydrocyclized at a relatively low temperature, and is represented by the formula (2) such as carbazole and dibenzofuran. The condensed ring compound can be produced with high selectivity and high efficiency.
Further, since the palladium hydroxide-supported solid catalyst of the present invention is a solid catalyst, it can be easily recovered as compared with a conventional homogeneous catalyst, and thus is suitable for catalyst reuse.

（式（１）中、Ｒ¹及びＲ²は、それぞれ独立して水素原子、ハロゲン原子、シアノ基、ニトロ基、ヒドロキシ基、置換基を有してもよいアルキル基、アルコキシ基、アリール基、アリールオキシ基、アシル基からなる群から選ばれる基を表し、２，２’位を除くすべての位置に結合できる。また、これらの置換基は環構造を形成していてもよい。ｍ、ｎは１〜４の整数をそれぞれ表す。
Ｘは、ＣＨ₂、酸素原子、硫黄原子、セレン原子又はＮＲ³を表し、Ｒ³は、水素原子又はアルキル基、アリール基、アシル基、アルコキシカルボニル基である。）

（式（２）中、Ｒ¹、Ｒ²、ｍ及びｎ、並びにＸはそれぞれ式（１）におけるＲ¹、Ｒ²、ｍ及びｎ、並びにＸと同義である。） "1. Production method of palladium hydroxide-supported solid catalyst"
The present invention is a method for producing a palladium hydroxide-supported catalyst for producing a condensed ring compound represented by formula (2) from a compound represented by formula (1),
(A) a step of supporting palladium hydroxide on a carrier by adding an alkali solution to a mixed solution containing a carrier and a palladium salt, and then distilling off the solvent;
(B) drying the carrier carrying the palladium hydroxide at a temperature of 150 ° C. or lower;
The present invention relates to a method for producing a palladium hydroxide-supported solid catalyst containing hydrogen (hereinafter sometimes referred to as “the method for producing a solid catalyst of the present invention”).

(In Formula (1), R ¹ and R ² are each independently a hydrogen atom, a halogen atom, a cyano group, a nitro group, a hydroxy group, an alkyl group that may have a substituent, an alkoxy group, an aryl group, Represents a group selected from the group consisting of an aryloxy group and an acyl group, and can be bonded to all positions except the 2,2 ′ position, and these substituents may form a ring structure. Represents an integer of 1 to 4, respectively.
X represents CH ₂ , an oxygen atom, a sulfur atom, a selenium atom or NR ³ , and R ³ represents a hydrogen atom or an alkyl group, an aryl group, an acyl group or an alkoxycarbonyl group. )

(Equation (2), R ^1, R ^2, m and n, and X have the same meanings as R ^1, R ^2, m and n, and X in each formula (1).)

In formula (1), R ¹ and R ² are each independently a hydrogen atom, a halogen atom, a cyano group, a nitro group, a hydroxy group, an optionally substituted alkyl group, an alkoxy group, an aryl group, an aryl It represents a group selected from the group consisting of an oxy group and an acyl group, and can be bonded to all positions except the 2,2 ′ positions. M and n each represent an integer of 1 to 4. These substituents may form a ring structure. X represents CH ₂ , an oxygen atom, a sulfur atom, a selenium atom or NR ³ , and R ³ represents a hydrogen atom or an alkyl group, an aryl group, an acyl group or an alkoxycarbonyl group.
In the formula (2), R ¹ , R ² and m, n are respectively synonymous with R ¹ , R ^2, m, and n in the formula (1), and X is synonymous with X in the formula (1). .

  The details of the condensed ring compound represented by the formula (2) from the compound represented by the formula (1) are described later in “2. Method for producing the condensed ring compound represented by the formula (2)”. explain.

The palladium hydroxide-supported solid catalyst obtained by the method for producing a solid catalyst of the present invention is obtained by oxidatively coupling the 2,2′-position of the compound represented by the above formula (1) and dehydrocyclizing it. It acts as a catalyst for the reaction for producing the target compound represented by the formula (2).
In the present specification, the palladium hydroxide may be hereinafter referred to as “Pd (OH) ₂ ”, but includes a crystal and an amorphous one, and the Pd (OH) _{2 has} a stoichiometric amount. It is not necessary to satisfy the theoretical composition.

One of the main features of the method for producing a solid catalyst of the present invention is that the temperature at which Pd (OH) ₂ immobilized on the carrier in step (A) is dried in step (B) is 150 ° C. or lower. (Preferably at 110 ° C. or lower), and it has been found that when it is treated at such a low temperature, it has excellent catalytic activity for the above reaction.
On the other hand, when the catalyst carrying Pd (OH) ₂ is heat-treated at a temperature exceeding 150 ° C., the catalytic activity is rapidly reduced. On the other hand, it has a catalytic activity at 150 ° C. or lower and a higher catalytic activity at 110 ° C. or lower.
Note that a catalyst supporting reduced Pd metal (zero valence) or PdO (divalent) has low catalytic activity, and the above reaction does not proceed, or the reaction rate at an industrial level cannot be obtained.

  Moreover, the manufacturing method of the solid catalyst of this invention has the merit that baking at high temperature and a reduction process are not required.

Hereinafter, the method for producing the solid catalyst of the present invention will be described in more detail.
The compound represented by the above formula (1) and the condensed ring compound represented by the formula (2) will be described in “Method for producing condensed ring compound represented by formula (2)” described later.

The palladium salt is not particularly limited as long as it is easily dissolved in a solvent and can form Pd hydroxide by mixing with an alkali solution. Specifically, palladium (II) chloride, tetrachloropalladium (II) acid and salts thereof, palladium bromide, palladium (II) acetate, palladium (II) trifluoroacetate, palladium (II) nitrate, and tetraammine palladium nitrate (II) etc. can be mentioned.
Among these, palladium (II) chloride, which is dissolved in water and relatively inexpensive, is a suitable example. One palladium salt may be used, or two or more palladium salts may be used simultaneously.

There is no restriction | limiting in particular as a support | carrier, For example, a carbon material, a metal oxide, etc. are mentioned.
Examples of the carbon material include activated carbon, ketjen black, graphite, carbon black, nanoporous carbon, and carbon nanotube.
Examples of the metal oxide include zirconia (ZrO ₂ ), alumina (Al ₂ O ₃ ), silica (SiO ₂ ), magnesia (MgO), ceria (CeO ₂ ), calcia (CaO), titania (TiO ₂ ), and cobalt oxide. (Co ₃ O ₄ ) and the like. These composite oxides may be used, and other elements may be doped as long as the physical properties are not impaired.
Among these, metal oxides are preferable, and zirconia and titania are particularly preferable because a solid catalyst having high catalytic activity and high product selectivity can be obtained.

In general, the larger the specific surface area of the carrier, the more uniformly the Pd hydroxide is supported on the surface of the carrier, making it possible to produce a catalyst loaded with many useful components, but it is possible to support palladium hydroxide. If it has a specific surface area of a grade, it will not specifically limit.
On the other hand, the catalytic activity of the supported Pd hydroxide may change due to the interaction between the support and the Pd hydroxide, and this interaction depends on the type of the support and the production conditions. For example, an oxide support having a small surface area, such as a zirconia support, may have higher catalytic activity than a carbon support having a large surface area.
Taking zirconia (ZrO ₂ ), which is a suitable carrier, as an example, the specific surface area is preferably 10 m ² / g or more, and 50 m ² / g or more in order to have sufficient catalyst activity per unit weight of the catalyst. More preferred.

The shape of the carrier is not particularly limited and may be any shape, but is usually a powder. The form of the carrier may be any form such as a dense body or a porous body.
The average particle size in the case of particles is not particularly limited, but is preferably 5 nm to 1 mm. More preferably, it is 5 nm-100 micrometers.
The average particle diameter of the carrier is calculated as an average value of the particle diameters by, for example, arbitrarily extracting a predetermined number of particles with a scanning electron microscope (SEM), measuring the particle diameter (diameter) for each of them. The method etc. are mentioned.
When the shape of the fine particles is other than a spherical shape, the length in the direction indicating the maximum length of the particles is defined as the particle size.

  Two or more types of carriers having different particle diameters and / or specific surface areas can be mixed.

  In step (A), first, a carrier and a solution in which a palladium salt is dissolved are mixed to prepare a palladium salt solution in which the carrier is dispersed.

The solvent in the palladium salt solution may be any solvent that dissolves the palladium salt to be used, and is usually water.
In addition to water, the solvent includes alcohols such as methanol, ethanol, n-propanol, and isopropyl alcohol, and hydrocarbons such as acetone, hexane, and benzene as long as the effects of the present invention are not impaired. Also good.

  The palladium salt solution may contain an inorganic acid in order to dissolve the palladium precursor in the solution. Examples of the inorganic acid include hydrochloric acid, nitric acid, sulfuric acid and the like.

The Pd concentration in the palladium salt solution is 0.01 to 10 mmol / L, preferably 0.1 to 5 mmol / L in terms of Pd atoms.
If it is less than 0.01 mmol / L, it is difficult to deposit and precipitate palladium hydroxide on the support, and if it exceeds 5 mmol / L, palladium hydroxide precipitates in the solution and the palladium hydroxide is uneven. There is a problem that it will settle.

  As for the quantity of the solvent used in a process (A), 10-5000 are preferable by mass ratio with respect to a support | carrier.

  The carrier and the palladium salt solution may be mixed by a conventionally known method and sufficiently mixed until uniform.

  An alkali is added to the solution obtained by mixing the support and the palladium salt solution, and the pH is adjusted to 7 to 10, whereby palladium hydroxide is deposited and precipitated on the support.

Examples of the alkali component in the alkaline solution include alkali metal salts such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium hydrogen carbonate, potassium carbonate, cesium carbonate and the like.
The alkali concentration of the alkaline solution is 0.05 to 2 mol / L, preferably 0.1 to 1 mol / L. If it is less than 0.05 mol / L, the amount of the alkaline solution to be added increases, and the palladium concentration decreases. When it exceeds 2 mol / L, there is a problem that it is difficult to control pH.

The alkali solvent is preferably the same solvent as the palladium salt solution.
That is, although it is usually water, in addition to water, alcohols such as methanol, ethanol, n-propanol, and isopropyl alcohol, hydrocarbons such as acetone, hexane, and benzene, and the like do not impair the effects of the present invention. May be included.

  There is no particular limitation on the method of adding an alkaline solution to a mixed solution containing a support and a palladium salt solution. However, if the production of palladium hydroxide is not uniform, the catalytic activity of the produced solid catalyst may be reduced. In order to make it non-uniform, a method of dropping an alkaline solution into a mixed solution containing a carrier and a palladium salt solution is preferable.

The stirring temperature is 20 to 90 ° C, preferably 20 to 80 ° C. When it is lower than 20 ° C., the precipitation of palladium hydroxide is delayed. When the temperature is higher than 90 ° C., a precipitate of palladium hydroxide is generated not only on the support but also in the solution, and the palladium hydroxide precipitates unevenly. The stirring time is preferably 3 to 30 hours at 20 to 40 ° C., more preferably 5 to 24 hours. In 40-90 degreeC, 30 minutes-5 hours are preferable, More preferably, they are 1 hour-4 hours. If the stirring time is too short, the precipitation of palladium hydroxide may be insufficient, and if the stirring time is too long, the aggregation of palladium hydroxide is a concern.
Next, by removing the solvent from the suspension, it is possible to obtain a solid (preferably containing a little solvent here) in which the palladium hydroxide is supported on the carrier.
A method for removing the solvent is not particularly limited, but suction filtration is simple.

Next, the step (B) will be described.
Step (B) is a step of drying the carrier on which the above-described palladium hydroxide is supported at a temperature of 150 ° C. or lower.

The drying temperature is required to be 150 ° C. or lower in order for the palladium hydroxide to suppress the change to palladium oxide. The minimum drying temperature is preferably 20 ° C. or higher.
The drying temperature is preferably 70 ° C. or higher and 120 ° C. or lower, and more preferably 70 ° C. or higher and 110 ° C. or lower in that a catalyst with a higher product yield can be produced.
The drying method is not particularly limited, and examples thereof include a heat drying process using a box furnace, a vacuum drying process using a vacuum dryer, and a freeze vacuum drying using liquid nitrogen.

  The drying time requires a time for the solvent to be sufficiently removed, and is usually 2 to 24 hours, although it varies depending on the drying temperature. If it is 2 hours or less, the removal of water is not sufficient, and even if it is dried for 24 hours or more, the subsequent water removal has little effect. You may dry under reduced pressure as needed.

The palladium hydroxide-supported solid catalyst of the present invention (hereinafter referred to as “the solid catalyst of the present invention”) is obtained by the above-described production method.
Although the amount of palladium hydroxide supported on the solid catalyst of the present invention depends on the amount of support and palladium salt charged in the above step (A), not all palladium components are supported on the support. There may be a slight deviation between the charged amount and the actual loaded amount.
The actual amount of palladium hydroxide supported can be evaluated by, for example, fluorescent X-ray analysis (XRF).

  The solid catalyst of the present invention can be suitably used in the following method for producing a condensed ring compound.

（式（１）中、Ｒ¹及びＲ²は、それぞれ独立して水素原子、ハロゲン原子、シアノ基、ニトロ基、ヒドロキシ基、置換基を有してもよいアルキル基、アルコキシ基、アリール基、アリールオキシ基、アシル基からなる群から選ばれる基を表し、２，２’位を除くすべての位置に結合できる。また、これらの置換基は環構造を形成していてもよい。ｍ、ｎは１〜４の整数をそれぞれ表す。
Ｘは、ＣＨ₂、酸素原子、硫黄原子、セレン原子又はＮＲ³を表し、Ｒ³は、水素原子又はアルキル基、アリール基、アシル基、アルコキシカルボニル基である。）

（式（２）中、Ｒ¹、Ｒ²、ｍ及びｎ、並びにＸはそれぞれ式（１）におけるＲ¹、Ｒ²、ｍ及びｎ、並びにＸと同義である。） “2. Method for producing condensed ring compound represented by formula (2)”
In the method for producing a fused ring compound of the present invention, the solid catalyst of the present invention obtained by the production method described above and the compound represented by the formula (1) are contained in a liquid phase containing a Bronsted acid in an oxygen atmosphere. It is made to contact at 150 degrees C or less, and the condensed ring compound represented by Formula (2) is manufactured.
That is, in the compound having two adjacent aryl groups represented by the formula (1), the object represented by the formula (2) is obtained by oxidative coupling and dehydrocyclization at the 2,2 ′ positions. A compound is produced.

(In Formula (1), R ¹ and R ² are each independently a hydrogen atom, a halogen atom, a cyano group, a nitro group, a hydroxy group, an alkyl group that may have a substituent, an alkoxy group, an aryl group, Represents a group selected from the group consisting of an aryloxy group and an acyl group, and can be bonded to all positions except the 2,2 ′ position, and these substituents may form a ring structure. Represents an integer of 1 to 4, respectively.
X represents CH ₂ , an oxygen atom, a sulfur atom, a selenium atom or NR ³ , and R ³ represents a hydrogen atom or an alkyl group, an aryl group, an acyl group or an alkoxycarbonyl group. )

(Equation (2), R ^1, R ^2, m and n, and X have the same meanings as R ^1, R ^2, m and n, and X in each formula (1).)

As described above, in the compound of the formula (1) that is the raw material compound, R ¹ and R ² may each independently have a hydrogen atom, a halogen atom, a cyano group, a nitro group, a hydroxy group, or a substituent. It is a group selected from the group consisting of an alkyl group, an alkoxy group, an aryl group, an aryloxy group, and an acyl group, and can be bonded to all positions except the 2,2 ′ positions. M and n each represent an integer of 1 to 4. These substituents may form a ring structure.

R ¹ and R ² are preferably selected so as not to significantly suppress the above-described 2,2′-position dehydrocyclization. An example of a suitable group is an alkyl group such as a methyl group, an alkoxy group such as a methoxy group, an aryloxy group, a nitro group, a fluorine, and an acetyl group.

X represents CH ₂ , an oxygen atom, a sulfur atom, a selenium atom or NR ³ , and R ³ represents a hydrogen atom, an alkyl group, an aryl group, an acyl group or an alkoxycarbonyl group.

In the condensed ring compound of the formula (2) which is the product compound, R ¹ , R ² , m and n, and X and R ³ are R ¹ , R ² , m and n and X and R in the formula (1), respectively. Synonymous with ³ .

A preferred application example of the method for producing a fused ring compound of the present invention is that the fused ring compound represented by the formula (2) is one selected from carbazole, fluorene, dibenzothiophene, dibenzoselenophene and dibenzofuran, or these This is the case when it is a derivative of a compound.
Here, as a derivative, preferable groups are an alkyl group such as a methyl group, an alkoxy group such as a methoxy group, an aryloxy group, a nitro group, a fluorine, and an acetyl group.

  A more preferable application example of the method for producing a fused ring compound of the present invention is that the starting compound is diphenylamine (formula (1a)) in which X in formula (1) is NH, and the product compound is carbazole (formula (2a) )).

  In another more preferable application example, the raw material compound is diphenyl ether (formula (1b)) in which X in formula (1) is O (oxygen atom), and the product compound is dibenzofuran (formula (2b)). Is the case.

  In the present invention, the compound represented by the above formula (1) as a raw material may be used alone or as a mixture of several kinds, but separation of the product becomes difficult, resulting in a complicated process. Therefore, it is preferable to use it alone.

As described above, in the method for producing a fused ring compound of the present invention, an oxygen or air atmosphere is essential because dehydrocyclization is performed by oxidative coupling.
The oxygen pressure in the reaction system is usually in the range of oxygen partial pressure of 0.02 to 3.0 MPa, although it depends on the types of raw material compound and product compound.
If the oxygen pressure in the reaction system is too low, the reaction rate becomes slow, and if it is too high, there is a problem that the product selectivity may be lowered due to side reactions.
In particular, when the raw material compound is diphenylamine and the product compound is carbazole, the oxygen partial pressure of the reaction system is preferably 0.02 to 1.0 MPa, more preferably 0.1 to 0.5 MPa.
Further, when the raw material compound is dibenzofuran and the product compound is dibenzofuran, the oxygen partial pressure of the reaction system is preferably 0.1 to 2.0 MPa, more preferably 0.8 to 1.5 MPa. is there.

The reaction temperature can be synthesized at 150 ° C. or lower, although it depends on the type of raw material compound and product compound. When the temperature exceeds 150 ° C., there is a problem that the product selectivity may be lowered.
Moreover, the minimum temperature of reaction temperature should just be the temperature which the said reaction advances, and is 60 degreeC or more normally, Preferably it is 80 degreeC or more. If it is less than 60 ° C., it is not preferable from the viewpoint of industrial productivity from the viewpoint of synthesis speed.
In particular, when the raw material compound is diphenylamine and the product compound is carbazole, the reaction temperature is preferably from 80 to 120 ° C, more preferably from 80 to 100 ° C.
When the raw material compound is diphenyl ether and the product compound is dibenzofuran, the reaction temperature is preferably 100 to 150 ° C, more preferably 120 to 150 ° C.

It is essential that the solvent used for the reaction contains a Bronsted acid such as an organic acid or phosphoric acid. Examples of the organic acid include formic acid, acetic acid, butanoic acid, and pivalic acid. These may be used alone or in combination of two or more.
In addition to Bronsted acids such as organic acids and phosphoric acids, mixed solvents containing other solvents can also be used.
Examples of other solvents include 1,4-dioxane, toluene, methanol, chloroform, dimethylformamide (DMF), tetrahydrofuran (THF), ethyl acetate, acetonitrile, and the like. In addition to the organic solvent, water can be used.

In addition, in the manufacturing method of the condensed ring compound of this invention, a suitable solvent is dependent on the kind of raw material compound and a production | generation compound.
For example, when the raw material compound is diphenylamine and the product compound is carbazole, only an organic acid such as formic acid, acetic acid, and pivalic acid may be used as a solvent, but a mixed solvent including, for example, an organic solvent can also be used. In particular, when a mixed solvent of acetic acid and 1,4-dioxane, toluene, ethyl acetate, and tetrahydrofuran is used, the yield is higher than that of acetic acid alone. Since an organic solvent can be used as a solvent, there is an advantage that the neutralization step of the solvent after the reaction can be simplified.
In addition, since the reaction does not proceed when the organic acid is not present, the ratio of the organic acid when the organic acid is used is 5 to 100% by volume, preferably 20 to 20%. 80% by volume.
Further, when the raw material compound is diphenyl ether and the product compound is dibenzofuran, the yield is better than acetic acid when a solvent containing pivalic acid is used as the organic acid. Moreover, a higher yield can be obtained by using pivalic acid alone as a solvent than mixing with another organic solvent.
In addition, as for the mixed solvent ratio of pivalic acid and another organic solvent, it is preferable that the ratio of pivalic acid is 50-100 volume%.

In the method for producing a condensed ring compound of the present invention, the solid catalyst of the present invention is preferably used in a state of being suspended in a reaction solution for performing liquid phase oxidation, but may be used in a fixed bed.
The amount of suitable catalyst used depends on the type of raw material compound and product compound and the production amount, but when the amount of the solution present in the reactor is 100 parts by mass, the solid catalyst present in the reactor is usually 1 to 200 parts by mass, preferably 10 to 70 parts by mass.

Further, the catalytic activity of the solid catalyst of the present invention also varies depending on the supported amount of palladium hydroxide, and there is a suitable supported amount depending on the type of raw material compound and product compound.
For example, when the raw material compound is diphenylamine and the product compound is carbazole, the weight ratio of palladium hydroxide to the carrier (Pd atom conversion) is preferably 1 to 30% by weight, more preferably 5 to 20% by weight. %.
When the starting compound is diphenyl ether and the product compound is dibenzofuran, the weight ratio of palladium hydroxide to the carrier (Pd atom conversion) is preferably 10 to 50% by weight, more preferably 10 to 10% by weight. 40% by weight.

  The reaction time is appropriately selected depending on various conditions such as the raw material compound, the type of the produced compound, the type of the solvent, and the reaction temperature.

The reaction product after the reaction is separated and recovered by a conventionally known method.
Specifically, a method of neutralizing the filtrate, extracting with an organic solvent such as dichloromethane, and drying the organic phase with sodium sulfate can be mentioned.

  The palladium hydroxide-supported solid catalyst after the reaction can be easily separated and recovered by using a method such as filtration or centrifugation. The separated palladium hydroxide-supported solid catalyst is appropriately dried and can be reused after reactivation as necessary.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is changed.

The main chemicals and analyzers used are as follows.
(Palladium salt)
・ Palladium chloride (II) (Tanaka Kikinzoku Kogyo Co., Ltd.)
(Carrier)
(A) Zirconia (ZrO ₂ )
Daiichi Rare Element Chemical Co., Ltd., product number: RC-100
Specific surface area: 80-120 m ² / g
Average particle size: 1.5-4 μm

(B) Carbon (Ketjen Black)
Lion Corporation, product number: EC300J
Specific surface area: 800 m ² / g
Average particle size: 40 nm

(C) Alumina (Al ₂ O ₃ )
Catalytic Society Reference Catalyst, Part Number: JRC-ALO-8
Specific surface area: 160 m ² / g

(D) Titania (TiO ₂ )
(A) TiO ₂ (Rutile + Anatase)
Nippon Aerosil Co., Ltd., product number: P-25
Specific surface area: 50 m ² / g
Average particle size: 20nm

(B) TiO ₂ (Anatase)
Titanium Industry Co., Ltd., product number: ST-111
Specific surface area: 310 m ² / g

(E) Ceria (CeO ₂ )
Shin-Etsu Chemical Co., Ltd. Specific surface area: 161m ² / g

"Analysis equipment"
・ Energy dispersive X-ray fluorescence analyzer (XRF)
Made by Shimadzu Corporation, model number: EDX-720

·Gas chromatograph
Agilent 6850 Series GC System, capillary column J & W Scientific, HP-1 (id 0.32 mm, film thickness 0.25 μm, 30 m)

1. Preparation of solid catalyst supporting Pd hydroxide “Solid Catalyst A1”
Palladium (II) chloride (PdCl ₂ ) (189 mg, 1 mmol) is added to distilled water (1050 mL), a small amount of hydrochloric acid is added to dissolve PdCl ₂ , and the aqueous solution is adjusted so that the Pd concentration is 1 mmol / L. Prepared.
Next, an aqueous NaOH solution was added dropwise to this aqueous solution to adjust the pH to 8, and 1 g of ZrO ₂ powder was added as a carrier, and the mixture was stirred at 70 ° C. for 1 hour while maintaining the pH of 8.
Next, after washing with distilled water until the pH of the solution was stabilized, suction filtration was performed, and drying was performed at 70 ° C. overnight to obtain 10 wt% (Pd conversion, charged amount) of solid catalyst A1.
The amount of Pd supported on the solid catalyst A1 evaluated by fluorescent X-ray analysis was 8.6 wt% (Pd conversion).

"Solid Catalyst A3"
The same procedure as in the preparation of the solid catalyst A1, except that an aqueous solution of palladium (II) chloride with the Pd concentration fixed at 1 mmol / L and 1 wt% (in terms of Pd, charged amount) of ZrO ₂ powder was added. A solid catalyst A3 was obtained.

"Solid Catalyst A4"
A solid catalyst except that a palladium (II) chloride aqueous solution having a Pd concentration fixed at 1 mmol / L, an amount of ZrO ₂ powder of 30 wt% (Pd conversion, charged amount) was added, and the drying temperature was 100 ° C. A solid catalyst A4 was obtained by the same operation as in the preparation of A1.

"Solid Catalyst A5"
The solid catalyst A5 was obtained by the same operation as the preparation of the solid catalyst A1, except that the pH of the aqueous solution was adjusted to 10, stirred at 20 ° C. for 24 hours, and the drying temperature was changed from 70 ° C. to 100 ° C.

"Solid Catalyst A6"
A palladium (II) chloride aqueous solution with a Pd concentration fixed at 1 mmol / L and an operation similar to the preparation of the solid catalyst A1 except that 20 wt% (in terms of Pd, charged amount) of ZrO ₂ powder was added. , Solid catalyst A6 was obtained.

"Solid Catalyst A7"
A palladium (II) chloride aqueous solution with a Pd concentration fixed at 1 mmol / L and the same operation as in the preparation of the solid catalyst A1, except that ZrO ₂ powder was added in an amount of 30 wt% (Pd equivalent, charged amount). The solid catalyst A7 was obtained.

"Solid catalyst B1"
A solid catalyst B1 was obtained by the same operation as the preparation of the solid catalyst A1, except that Carbon powder was used instead of ZrO ₂ as a support.

"Solid catalyst B2"
A solid catalyst B2 was obtained in the same manner as in the preparation of the solid catalyst B1, except that the amount of Pd conversion was changed to 5 wt%.

"Solid Catalyst B3"
A solid catalyst B3 was obtained in the same manner as in the preparation of the solid catalyst B1, except that the drying temperature was 200 ° C.

"Solid catalyst C1"
A solid catalyst C1 was obtained in the same manner as in the preparation of the solid catalyst A1, except that Al ₂ O ₃ powder was used instead of ZrO ₂ as a support. The amount of Pd supported on the solid catalyst C1 evaluated by fluorescent X-ray analysis was 8.0 wt% (Pd conversion).

"Solid catalyst D1"
A solid catalyst D1 was obtained in the same manner as in the preparation of the solid catalyst A1, except that TiO ₂ powder (P-25) was used instead of ZrO ₂ as a support.

"Solid catalyst D2"
An aqueous palladium (II) chloride solution having a Pd concentration fixed at 1 mmol / L, an amount of TiO ₂ powder (ST-111) of 40 wt% (Pd conversion, charged amount) was added, and the drying temperature was 100 ° C. Except for the above, a solid catalyst D2 was obtained in the same manner as in the preparation of the solid catalyst D1.

"Solid catalyst E1"
A solid catalyst E1 was obtained in the same manner as in the preparation of the solid catalyst A1, except that CeO ₂ powder was used instead of ZrO ₂ as a support.

2. Synthesis of carbazole 2-1. Comparison of Supports Carbazoles were synthesized under the same conditions using Pd hydroxide supported solid catalysts using different supports, and the carbazole yields were compared.

(Carbazole synthesis example 1)
Diphenylamine (1 mmol), solid catalyst A1 (50 mg, Pd 5 mol%), 1,4-dioxane (1.5 mL) and acetic acid (1.5 mL) as a solvent and a magnetic stir bar were added to the autoclave, and then oxygen was gauged. Until 0.25 MPa.
Subsequently, after stirring with heating at 100 ° C. for 12 hours, the catalyst was filtered through Celite (registered trademark).
The filtrate was neutralized and extracted with dichloromethane, and the organic phase was dried over sodium sulfate. When the filtrate was analyzed by gas chromatography using tridecane as an internal standard substance, the conversion rate of diphenylamine was 92% and the yield of carbazole was 80%. Table 1 summarizes the catalysts used, carbazole synthesis conditions, and carbazole yield.

(Carbazole Synthesis Example 1 ′)
The synthesis was performed in the same manner as in Carbazole Synthesis Example 1 except that the solid catalyst A5 was used in place of the solid catalyst A1, and the filtrate was analyzed. The yield of carbazole was 85%. Table 1 summarizes the catalysts used, carbazole synthesis conditions, and carbazole yield.

(Carbazole synthesis example 2)
The synthesis was performed in the same manner as in Carbazole Synthesis Example 1 except that the solid catalyst B1 was used instead of the solid catalyst A1, and the filtrate was analyzed. As a result, the yield of carbazole was 63%. Table 1 summarizes the catalysts used, carbazole synthesis conditions, and carbazole yield.

(Carbazole synthesis example 3)
The synthesis was performed in the same manner as in Carbazole Synthesis Example 1 except that the solid catalyst C1 was used in place of the solid catalyst A1, and the filtrate was analyzed. The yield of carbazole was 78%. Table 1 summarizes the catalysts used, carbazole synthesis conditions, and carbazole yield.

(Carbazole synthesis example 4)
The synthesis was performed in the same manner as in Carbazole Synthesis Example 1 except that the solid catalyst D1 was used instead of the solid catalyst A1, and the filtrate was analyzed. The yield of carbazole was 59%. Table 1 summarizes the catalysts used, carbazole synthesis conditions, and carbazole yield.

(Carbazole synthesis example 5)
The synthesis was performed in the same manner as in Carbazole Synthesis Example 1 except that the solid catalyst E1 was used instead of the solid catalyst A1, and the filtrate was analyzed. The yield of carbazole was 41%. Table 1 summarizes the catalysts used, carbazole synthesis conditions, and carbazole yield.

(Carbazole Synthesis Example 6)
Synthesis was performed in the same manner as in Carbazole Synthesis Example 1 except that Pd (OAc) ₂ (50 mg, Pd 2.3 mol%), which is a homogeneous catalyst, was used instead of the solid catalyst A1, and the solution after the reaction was analyzed. The yield of carbazole was 7%. Table 1 summarizes the catalysts used, carbazole synthesis conditions, and carbazole yield.

(Carbazole Synthesis Example 7)
The synthesis was performed in the same manner as in Carbazole Synthesis Example 1 except that a PdO catalyst was used in place of the solid catalyst A1, and the filtrate was analyzed. The yield of carbazole was 2%. Table 1 summarizes the catalysts used, carbazole synthesis conditions, and carbazole yield.
The PdO catalyst was prepared by heat treating the palladium hydroxide supported catalyst (A1) at 300 ° C. for 4 hours in the air.

2-2. Comparison of catalyst activity at drying temperature Using a Pd hydroxide-supported solid catalyst (solid catalysts B1 to B3) dried at different temperatures, carbazole was synthesized in the same manner as in carbazole synthesis example 1, and the filtrate was analyzed.
Carbazole of carbazole synthesis example 2 (solid catalyst B1, drying temperature: 80 ° C.), carbazole synthesis example 8 (solid catalyst B2, drying temperature: 100 ° C.), carbazole synthesis example 9 (solid catalyst B3 (drying temperature: 200 ° C.)) Yields of 63%, 46% and 8%, respectively. Table 2 summarizes the catalysts used, the carbazole synthesis conditions, and the carbazole yield.

  From this, it is considered that a part of the palladium hydroxide changed to PdO which is inactive to this reaction as the drying temperature increases.

2-3. Difference in Pd hydroxide loading amount Using solid catalysts A1 and A3 (support: ZrO ₂ ), the relationship between the Pd hydroxide loading amount (Pd conversion) and the carbazole yield was compared. Table 3 summarizes the catalysts used, carbazole synthesis conditions, and carbazole yield.

3. Synthesis of dibenzofuran (Dibenzofuran Synthesis Example 1)
Diphenyl ether (1 mmol), solid catalyst A4 (50 mg), pivalic acid (2.0 g), and a magnetic stir bar were added to the autoclave, and then oxygen was added until the gauge pressure reached 0.5 MPa. After heating and stirring at 120 ° C. for 60 hours, the catalyst was filtered through celite. When the filtrate was analyzed by gas chromatography using tridecane as an internal standard substance, the conversion of diphenyl ether was 62% and the yield of dibenzofuran was 41%. Table 4 summarizes the catalysts used, dibenzofuran synthesis conditions, and dibenzofuran yield.

(Dibenzofuran Synthesis Example 2)
Diphenyl ether (1 mmol), solid catalyst A4 (100 mg), pivalic acid (1.2 g), 1,4-dioxane (1.0 mL) and a magnetic stir bar were added to the autoclave, and oxygen was added at a gauge pressure of 0.5 MPa. Added until After heating and stirring at 120 ° C. for 48 hours, the catalyst was filtered through celite. When analyzed in the same manner as described above, the conversion rate of diphenyl ether was 55%, and the yield of dibenzofuran was 33%. Table 4 summarizes the catalysts used, dibenzofuran synthesis conditions, and dibenzofuran yield.

(Dibenzofuran Synthesis Example 3)
Diphenyl ether (1 mmol), solid catalyst A5 (30 mg), pivalic acid (0.7 g), and a magnetic stir bar were added to the autoclave, and then oxygen was added until the gauge pressure reached 0.5 MPa. After stirring with heating at 130 ° C. for 48 hours, the catalyst was filtered through celite. When analyzed in the same manner as described above, the conversion rate of diphenyl ether was 80%, and the yield of dibenzofuran was 69%. Table 4 summarizes the catalysts used, dibenzofuran synthesis conditions, and dibenzofuran yield.

(Dibenzofuran Synthesis Example 4)
Diphenyl ether (1 mmol), solid catalyst A6 (30 mg), pivalic acid (0.7 g), and a magnetic stir bar were added to the autoclave, and oxygen was added until the gauge pressure reached 0.5 MPa. After stirring with heating at 130 ° C. for 48 hours, the catalyst was filtered through celite. When analyzed in the same manner as described above, the conversion rate of diphenyl ether was 88%, and the yield of dibenzofuran was 80%. Table 4 summarizes the catalysts used, dibenzofuran synthesis conditions, and dibenzofuran yield.

(Dibenzofuran Synthesis Example 5)
Diphenyl ether (1 mmol), solid catalyst A6 (30 mg), pivalic acid (2 g), and a magnetic stir bar were added to the autoclave, and then oxygen was added until the gauge pressure reached 0.5 MPa. After stirring with heating at 130 ° C. for 48 hours, the catalyst was filtered through celite. When analyzed in the same manner as described above, the conversion rate of diphenyl ether was 64%, and the yield of dibenzofuran was 58%. Table 4 summarizes the catalysts used, dibenzofuran synthesis conditions, and dibenzofuran yield.

(Dibenzofuran Synthesis Example 6)
Diphenyl ether (1 mmol), solid catalyst A7 (50 mg), pivalic acid (2 g), and a magnetic stir bar were added to the autoclave, and then oxygen was added until the gauge pressure reached 0.5 MPa. After stirring with heating at 130 ° C. for 60 hours, the catalyst was filtered through celite. When analyzed in the same manner as described above, the conversion rate of diphenyl ether was 65%, and the yield of dibenzofuran was 62%. Table 4 summarizes the catalysts used, dibenzofuran synthesis conditions, and dibenzofuran yield.

(Dibenzofuran Synthesis Example 7)
Diphenyl ether (1 mmol), solid catalyst D2 (50 mg), pivalic acid (1.8 g), and a magnetic stir bar were added to the autoclave, and then oxygen was added until the gauge pressure reached 0.5 MPa. After heating and stirring at 120 ° C. for 60 hours, the catalyst was filtered through celite. When analyzed in the same manner as described above, the conversion rate of diphenyl ether was 46%, and the yield of dibenzofuran was 38%. Table 4 summarizes the catalysts used, dibenzofuran synthesis conditions, and dibenzofuran yield.

  According to the present invention, a palladium hydroxide-supported solid catalyst suitable for the synthesis of condensed ring compounds such as carbazole and dibenzofuran can be produced. The produced palladium hydroxide-supported solid catalyst has an excellent catalytic activity, and from an inexpensive raw material compound, industrially high value-added condensed ring compounds such as carbazole and dibenzofuran, high product selectivity and high efficiency. Can be manufactured.

Claims (16)

A method for producing a palladium hydroxide-supported catalyst for producing a condensed ring compound represented by formula (2) from a compound represented by formula (1),
(A) A step of supporting palladium hydroxide on a carrier by adding an alkali solution to a mixed solution containing the carrier and a palladium salt, and then distilling off the solvent;
And (B) drying the support on which the palladium hydroxide is supported at a temperature of 150 ° C. or less, and a method for producing a palladium hydroxide-supported solid catalyst.

(In Formula (1), R ¹ and R ² are each independently a hydrogen atom, a halogen atom, a cyano group, a nitro group, a hydroxy group, an alkyl group that may have a substituent, an alkoxy group, an aryl group, Represents a group selected from the group consisting of an aryloxy group and an acyl group, and can be bonded to all positions except the 2,2 ′ position, and these substituents may form a ring structure. Represents an integer of 1 to 4, respectively.
X represents CH ₂ , an oxygen atom, a sulfur atom, a selenium atom or NR ³ , and R ³ represents a hydrogen atom or an alkyl group, an aryl group, an acyl group or an alkoxycarbonyl group. )

(Equation (2), R ^1, R ^2, m and n, and X have the same meanings as R ^1, R ^2, m and n, and X in each formula (1).)   2. The method for producing a solid catalyst according to claim 1, wherein in step (A), a weight ratio of the palladium salt to the support is 1 wt% or more and 50 wt% or less.   The method for producing a solid catalyst according to claim 1 or 2, wherein the palladium salt is palladium (II) chloride.   The method for producing a solid catalyst according to claim 1, wherein the carrier is a metal oxide. The method for producing a solid catalyst according to claim 4, wherein the support is zirconia (ZrO ₂ ) or titania (TiO ₂ ).   The method for producing a solid catalyst according to any one of claims 1 to 5, wherein the drying temperature in the step (B) is 70 ° C or higher and 120 ° C or lower.   The fused ring compound represented by the formula (2) is one selected from carbazole, fluorene, dibenzothiophene, dibenzoselenophene and dibenzofuran, or a derivative of these compounds. A method for producing a solid catalyst.   A palladium hydroxide-supported solid catalyst produced by the production method according to claim 1. The palladium hydroxide-supported solid catalyst according to claim 8 and the compound represented by the formula (1) in a liquid phase containing Bronsted acid in an oxygen or air atmosphere at 60 ° C or higher and 150 ° C or lower. A method for producing a condensed ring compound, comprising bringing a condensed ring compound represented by Formula (2) into contact with each other.

(In Formula (1), R ¹ and R ² are each independently a hydrogen atom, a halogen atom, a cyano group, a nitro group, a hydroxy group, an alkyl group that may have a substituent, an alkoxy group, an aryl group, Represents a group selected from the group consisting of an aryloxy group and an acyl group, and can be bonded to all positions except the 2,2 ′ position, and these substituents may form a ring structure. Represents an integer of 1 to 4, respectively.
X represents CH ₂ , an oxygen atom, a sulfur atom, a selenium atom or NR ³ , and R ³ represents a hydrogen atom or an alkyl group, an aryl group, an acyl group or an alkoxycarbonyl group. )

(Equation (2), R ^1, R ^2, m and n, and X have the same meanings as R ^1, R ^2, m and n, and X in each formula (1).)   The fused ring compound according to claim 9, wherein the fused ring compound represented by the formula (2) is one selected from carbazole, fluorene, dibenzothiophene, dibenzoselenophene and dibenzofuran, or a derivative of these compounds. Production method. The compound represented by the formula (1) is diphenylamine, the condensed ring compound represented by the formula (2) is carbazole,
The method for producing a condensed ring compound according to claim 9, wherein the synthesis is performed under conditions of a reaction temperature of 60 ° C to 120 ° C and an oxygen partial pressure of 0.02 MPa to 1.0 MPa.   The method for producing a condensed ring compound according to claim 11, wherein the palladium hydroxide-supported solid catalyst has a weight ratio (in terms of Pd atoms) of palladium hydroxide to the support of 1 wt% to 30 wt%.   The liquid phase solvent is an organic acid or a mixed solvent containing an organic acid and at least one of 1,4-dioxane, toluene, ethyl acetate and tetrahydrofuran, and the ratio of the organic acid in the mixed solvent is It is 5 volume% or more and 100 volume% or less, The manufacturing method of the condensed ring compound of Claim 11 or 12. The compound represented by the formula (1) is diphenyl ether, the condensed ring compound represented by the formula (2) is dibenzofuran,
The method for producing a condensed ring compound according to claim 9, wherein the synthesis is performed under conditions of a reaction temperature of 80 ° C to 150 ° C and an oxygen partial pressure of 0.1 MPa to 2.0 MPa.   The method for producing a condensed ring compound according to claim 14, wherein in the palladium hydroxide-supported solid catalyst, the weight ratio of palladium hydroxide to the support (in terms of Pd atoms) is 10 wt% or more and 50 wt% or less.   The method for producing a fused ring compound according to claim 14 or 15, wherein the liquid phase solvent contains pivalic acid.