WO2021132239A1 - Method for producing indene - Google Patents

Abstract

Provided is a method for stably producing indene over a long time with a high yield using a zeolite catalyst, as a novel method for producing indene.　This method for producing indene comprises a dehydrogenation step of bringing a raw material composition including indene into contact with a zeolite catalyst having an MFI structure to obtain a reaction product including indene, wherein the zeolite catalyst includes, within the zeolite skeleton, at least one kind of metal atoms selected from transition metals or post-transition metals and has Lewis acidity and strong solid basicity.

Description

Indene manufacturing method

The present invention relates to a method for producing indene.

Inden is an industrially useful substance as a raw material for kumaron-indene resin and optical resin. As a method for producing indene, a method of recovering indene from a coal tar fraction is known, but the coal tar fraction contains many impurities such as benzonitrile and benzofuran, and the separation and recovery method by distillation is used. In particular, it is difficult to separate benzofurans with similar boiling points to obtain high-purity indene. As a method for producing high-purity indene, a method by a direct dehydrogenation reaction of tetrahydroindene is known (Patent Documents 1 to 3).
On the other hand, as a dehydrogenation catalyst used for the direct dehydrogenation reaction of butane, a zeolite catalyst and the like are known (Patent Document 4).

Japanese Unexamined Patent Publication No. 2000-63298 Japanese Unexamined Patent Publication No. 2000-63299 Japanese Unexamined Patent Publication No. 2013-133293 JP-A-2019-193921

However, in the conventional methods for producing inden as in Patent Documents 1 to 3, although the conversion rate of the raw material is good, it has been studied to stably produce inden in a high yield for a long period of time. It wasn't enough, and there was still room for improvement.

An object of the present invention is to provide a method for stably producing indene in a high yield for a long period of time using a zeolite catalyst as a new method for producing indene.

As a result of diligent studies by the present inventors to solve the above problems, indene can be stably produced from a raw material composition containing indane in a high yield for a long period of time by using a specific zeolite catalyst. We have found that we can do this, and have completed the present invention.

One aspect of the present invention relates to a method for producing indene, which comprises a dehydrogenation step of bringing a raw material composition containing indane into contact with a zeolite catalyst having an MFI structure to obtain a reaction product containing indene. In this production method, the zeolite catalyst contains at least one metal atom selected from a transition metal or a post-transition metal in the zeolite skeleton, and has Lewis acidity and strong solid basicity.

In one embodiment, the metal atom is one or more selected from Zn atom, Fe atom, and Ni atom, and the content of the metal atom may be 1 to 15 atom% with respect to the Si atom.

In one aspect, the zeolite catalyst may not contain an alkali metal or may contain 1 atom% or less of an alkali metal with respect to the Si atom of the zeolite skeleton.

In one embodiment, the zeolite catalyst may be a catalyst on which a Pt atom is supported.

In one embodiment, the raw material composition may further contain at least one or more of octahydroindene and hexahydroindene.

In one aspect, the raw material composition may further contain molecular hydrogen.

The production method according to one embodiment may further include a raw material synthesis step for obtaining indane by a dehydrogenation reaction of tetrahydroindene.

According to the present invention, as a new method for producing inden, it is possible to provide a method for stably producing inden in a high yield for a long period of time using a zeolite catalyst.

It is a figure which shows the result of the synchrotron XRD analysis of the zeolite catalyst and the Zn impregnated carrier catalyst which concerns on an Example. It is a figure which shows the result ^{of the 29} Si MAS NMR measurement of the zeolite catalyst which concerns on an Example. It is a figure which shows the result of the FT-IR analysis of the zeolite catalyst, the ZnO crystal, and the Zn impregnated supported catalyst which concerns on Example. It is a figure which shows the result of the FT-IR analysis of the catalyst which adsorbed pyridine to the zeolite catalyst, ZnO crystal, and the Zn impregnated supported catalyst which concerns on Example. It can be seen that Bronsted acid is almost absent in the zeolite catalyst according to the examples. Is a graph showing the results of CO ₂ -TPD analysis of zeolite catalysts and Zn impregnated supported catalyst according to the embodiment. In the zeolite catalyst according to the example, a desorption peak is observed at a high temperature of 500 ° C. or higher, indicating that a strong base point exists. It is a figure which shows the result _{of NH 3-} TPD analysis of the zeolite catalyst and the Zn impregnated carrier catalyst which concerns on Example. It is a figure which shows the correlation of the base amount of the zeolite catalyst which concerns on an Example, and the butadiene yield obtained by the dehydrogenation reaction of n-butane. CO ₂ -TPD basic sites of observed at 500 ° C. or higher desorption temperature analysis is large (Fig within the frame) as the active is found to be high. It is a figure which shows the correlation of the acid amount of the zeolite catalyst which concerns on an Example, and the butadiene yield obtained by the dehydrogenation reaction of n-butane. From the NH _3- TPD analysis, it can be seen that the higher the amount of Lewis acid (in the frame of the figure), the higher the activity. It is a graph which shows the indene yield at the time when 2, 4 and 6 hours have passed from the start of a reaction in the indene production of an Example and a comparative example. It is a graph which shows the indene yield from the start of a reaction to 24 hours in the indene production of an Example and a comparative example. It is a graph which shows the time-dependent change of the indene and hexahydroindene of the second stage outlet in the indene production of an Example.

Hereinafter, the production method of the present invention will be described in detail, but the description of the constituent requirements described below is an example (representative example) as an embodiment of the present invention, and is not specified in these contents. ..

The method for producing indene according to the present embodiment includes a dehydrogenation step of bringing a raw material composition containing indane into contact with a zeolite catalyst having an MFI structure to obtain a reaction product containing indene.
According to the production method according to the present embodiment, by adopting a specific zeolite catalyst, indene can be stably produced in a high yield for a long period of time.

(Zeolite catalyst)
The zeolite catalyst according to the present embodiment contains at least one metal atom selected from a transition metal or a post-transition metal in the zeolite skeleton, and has Lewis acidity and strong solid basicity.

In the zeolite catalyst according to the present embodiment, Bronsted acid is hardly present in the zeolite catalyst, and only Lewis acid is present. In general, it is known that the amount of by-products of the dehydrogenation reaction increases or decreases depending on the presence of Bronsted acid, but since the zeolite catalyst according to the present embodiment contains almost no Bronsted acid. , Side reactions can be controlled, and the generation of by-products can be suppressed. By using the zeolite catalyst according to the present embodiment for the production of inden, for example, it is conceivable that side reactions are suppressed and the inden selectivity is improved, coke generation due to polymerization of decomposition by-products is suppressed, and the like. Therefore, inden can be stably produced over a long period of time. Further, since the zeolite catalyst according to the present embodiment has the active sites of the dehydrogenation reaction arranged in a high dispersion, the zeolite catalyst according to the present embodiment is used for the production of indene, so that the indene can be produced in a high yield. Can be manufactured.

Here, zeolite _{is a crystal in which TO 4} units (T is the central atom) having a tetrahedral structure share an O atom and are three-dimensionally connected to form open regular micropores. It means a sex substance.

The transition metal means a metal belonging to the Group 3 to Group 12 elements of the periodic table in the periodic table of long-periodic elements based on the provisions of the IUPAC (International Union of Pure and Applied Chemistry).
The post-transition metal means a base metal having an atomic number after the transition metal of the 4th, 5th, and 6th periods of the periodic table in the periodic table.

The inclusion of metal atoms in the zeolite skeleton means that the metal atoms are introduced into the zeolite skeleton in the same manner as silicon (Si) by a method of mixing the metal atoms as a raw material for hydrothermal synthesis. The states containing metal atoms in the zeolite skeleton include, for example, XRD (X-ray Diffraction), NMR (Nuclear Magnetic Resonance spectroscopy), FT-IR (Fourier Transform Infrared Spectroscopy), XPS (X-ray Photoelectron Spectroscopy) and It can be grasped by various measurement methods such as ESCA (Electron Spectroscopy for Chemical Analysis).

Lewis acidity means the property of being able to accept unshared electron pairs, and means that, for example, when pyridine is adsorbed on a zeolite catalyst and FT-IR analysis is performed, an absorption band is detected in the vicinity of ^{1450 cm -1.} To do.

Solid basicity means that the surface of the zeolite catalyst is basic. And strong solid basic means that strong basicity of the surface of the zeolite catalyst, for example, TPD (Temperature Programmed Desorption) upon CO ₂ -TPD analyzed by the analyzer, the zeolite to a high temperature range of not lower than 500 ° C. It means that the peak derived from the catalyst is detected.

The zeolite catalyst according to this embodiment is a zeolite having a 10-membered ring structure and has an MFI structure. Zeolites having an MFI structure are not particularly limited, but are preferably crystalline metallosilicates. The zeolite having an MFI structure means a zeolite corresponding to MFI in the structure code stored in the database by the International Zeolite Association.
It can be confirmed by, for example, X-ray diffraction that the zeolite is a zeolite having a 10-membered ring structure, particularly an MFI structure.

The metal atom contained in the zeolite skeleton is not particularly limited as long as it is a transition metal atom or a post-transition metal atom, and for example, titanium (Ti), vanadium (V), iron (Fe), cobalt (Co), nickel ( Ni), copper (Cu), zinc (Zn), gallium (Ga), zirconium (Zr), indium (In) and the like can be used. Among these, zinc (Zn), nickel (Ni), and iron (Fe) are preferably used from the viewpoint of excellent reactivity in the dehydrogenation reaction. As the metal atom contained in the zeolite skeleton, one kind may be used alone, or two or more kinds may be used.

The content of the metal atom contained in the zeolite skeleton is not particularly limited, but is preferably 1 to 15 atom% and more preferably 2 to 10 atom% with respect to the silicon (Si) atom. When the content of the metal atom contained in the zeolite skeleton is at least the lower limit of the above range, the solid basicity of the zeolite catalyst becomes strong, and the reactivity of the dehydration reaction of indane is excellent. When the content of the metal atom contained in the zeolite skeleton is not more than the upper limit of the above range, the reaction efficiency of the dehydrogenation reaction of indane with respect to the metal content is excellent, which is preferable.

The content of the alkali metal contained in the zeolite catalyst is preferably not containing the alkali metal or is preferably 1 atom% or less, and more preferably 0.1 atom% or less with respect to the Si atom. When it is not more than the above upper limit value, it is preferable because the reactivity of the dehydrogenation reaction of indene can be maintained high while promoting the crystallization of zeolite.

From the viewpoint of improving moldability, the zeolite catalyst may further contain a molding aid as long as it does not deviate from the gist of the present invention. The molding aid may be, for example, at least one selected from the group consisting of thickeners, surfactants, water retention agents, plasticizers, binder raw materials and the like. The molding step of molding the zeolite catalyst may be performed at an appropriate stage in the manufacturing process of the zeolite catalyst in consideration of the reactivity of the molding aid.

The zeolite catalyst may be a catalyst in which platinum is supported on a carrier using a platinum (Pt) source. Examples of the platinum source include tetraammine platinum (II) acid, tetraammine platinum (II) acid salt (for example, nitrate), tetraammine platinum (II) acid hydroxide solution, dinitrodiammine platinum (II) nitric acid solution, and hexahydroxo. Examples thereof include a nitric acid solution of platinum (IV) and an ethanolamine solution of hexahydroxoplatinum (IV). As the platinum source, it is preferable to use a metal source containing no chlorine atom. By using a metal source that does not contain chlorine atoms, corrosion of the device can be suppressed and indane can be dehydrogenated more efficiently.

When platinum is supported on the zeolite catalyst, the content of platinum in the zeolite catalyst is usually 0.05 to 2.5 wt% based on the total amount of the zeolite catalyst. The amount of platinum carried is preferably 0.1 wt% or more based on the total amount of the zeolite catalyst. The amount of platinum supported is preferably 2.0 wt% or less based on the total amount of the zeolite catalyst. With such a loading amount, the platinum surface area per unit platinum weight becomes large, so that a more efficient reaction system can be realized.

As the zeolite catalyst, a catalyst that has been reduced as a pretreatment may be used. The reduction treatment can be carried out, for example, by holding the zeolite catalyst at 40 to 600 ° C. in an atmosphere of a reducing gas. The holding time may be, for example, 0.05 to 24 hours. The reducing gas may be, for example, a gas containing hydrogen, carbon monoxide, or the like. By using a reduction-treated zeolite catalyst, the initial induction period of the dehydrogenation reaction can be shortened. The initial induction period of the dehydrogenation reaction means a state in which, among the supported metals in the zeolite catalyst, there are very few metals in the reduced and active state, and the activity of the catalyst is low.

<Preparation method of zeolite catalyst>
The zeolite catalyst in the present embodiment can be prepared by treating a combination of a silica gel aging step, a hydrothermal synthesis step, and a firing step. This allows the zeolite catalyst to be prepared without the use of alkali metals, boron or aluminum.

As an example of a suitable production example of the zeolite catalyst according to the present embodiment, for example, a silica source, an organic structure defining agent (OSDA), and water are mixed and aged (stirred) at 100 ° C. or lower for 10 hours or more. Then, after mixing the transition metal atom or the post-transition metal atom as a metal source, hydrothermal synthesis is performed at 100 ° C. or higher, and then firing is performed at 500 ° C. or higher for 5 hours or longer.
When platinum is supported on the zeolite catalyst, the method for supporting platinum is not particularly limited, and for example, an impregnation method, a deposition method, a coprecipitation method, a kneading method, an ion exchange method, a pore filling method and the like can be used.

As the silica source, for example, a hydrolyzable silicon compound such as silicon alcoholate, silane, silicon tetrachloride, or water glass can be used.
The organic structure defining agent is not particularly limited as long as a zeolite having an MFI structure can be obtained, and for example, a quaternary alkylammonium salt, an amine or the like can be used. As the organic structure defining agent, one kind may be used alone, or two or more kinds may be mixed and used.

As an example of a suitable production example of the zeolite catalyst according to the present embodiment, a step of washing the synthetic reaction product with water before firing the synthetic reaction product obtained after hydrothermal synthesis at 500 ° C. or higher for 5 hours or more is further performed. It is preferable to include it. By including the step of washing with water, the influence of alkali such as sodium on the zeolite catalyst can be reduced.

The above-mentioned method is an example of a suitable production example for preparing a zeolite catalyst without using alkali metal, boron or aluminum, but the production method of the present embodiment does not deviate from the gist of the present invention. For example, it does not limit the use of alkali metals, boron or aluminum. For example, in hydrothermal synthesis, an alkali metal may be mixed as long as it does not deviate from the gist of the present invention. By mixing the alkali metal, crystallization of the zeolite is promoted, and there is a tendency that a zeolite catalyst having an MFI structure in which a transition metal atom or a post-transition metal atom is introduced into the zeolite skeleton can be easily obtained.
Examples of the alkali metal include sodium (Na), potassium (K), rubidium (Rb) and the like. Of these, sodium (Na) is preferred. As the mixing amount of the alkali metal, as described above, it is preferable to mix an amount of 1 atom% or less with respect to the Si atom in the zeolite catalyst.

By the above method, a transition metal atom or a post-transition metal atom is introduced into the skeleton of zeolite, and a zeolite catalyst in which active sites are highly dispersed can be obtained. Furthermore, it is possible to obtain a zeolite catalyst having a strong solid basicity in which Bronsted acid is almost absent and only Lewis acid is present.

(Indene manufacturing method)
In the production method according to the present embodiment, in the dehydrogenation step, the raw material composition containing indane is brought into contact with the above-mentioned zeolite catalyst. As a result, a dehydrogenation reaction of indane occurs, and a reaction product containing indene is obtained.

<Raw material composition>
The raw material composition may contain at least indane, but it is preferable that at least one of octahydroindene and hexahydroindene is further contained. Since the zeolite catalyst according to the present embodiment has excellent reactivity in the dehydrogenation reaction, indene can be efficiently produced by containing at least one of octahydroindene and hexahydroindene.

Octahydroindene has two isomers, a cis form and a trans form, and hexahydroindene has a plurality of isomers having different double bond positions. Hexahydroindene has a structure in which one molecule of hydrogen is dehydrogenated from octahydroindene, so that it is easily dehydrogenated and indene is likely to occur.
The origin of production of indane, octahydroindene and hexahydroindene (hereinafter, may be referred to as "indane mixture") is not particularly limited. For example, tetrahydroindene may be obtained by a dehydrogenation reaction. At this time, a mixture in which compounds other than the indane mixture resulting from the production method are arbitrarily mixed may be used as it is, or a purified product may be used.

When octahydroindene or hexahydroindene is contained as the raw material composition, the mixing ratio of indane, octahydroindene, and hexahydroindene is not particularly limited, and for example, the mixing ratio depends on the ratio due to the production method. May be. For example, the mixing ratio (wt%) of indane and hexahydroindene is preferably 40 to 90: 1 to 60.
The mixing ratio of indane, octahydroindene, and hexahydroindene can be measured using a gas chromatograph analyzer.

The raw material composition may further contain an indane or a compound other than the indane mixture. The raw material composition may further contain, for example, an inert gas such as nitrogen or argon, steam, molecular hydrogen, oxygen, carbon monoxide, carbon dioxide, alkanes, olefins and the like. Among these, the raw material composition preferably contains molecular hydrogen from the viewpoint of improving the reaction efficiency in the dehydrogenation reaction of indane.
Generally, in the dehydrogenation reaction, it is known that the coexistence of molecular hydrogen reduces the yield from the viewpoint of thermodynamic equilibrium constraint. However, the present inventors have found that when the zeolite catalyst of the present embodiment is used, the reaction efficiency in the dehydrogenation reaction of indane or an indane mixture can be improved by intentionally coexisting with molecular hydrogen. It was. Therefore, the raw material composition preferably contains molecular hydrogen.

When the raw material composition contains a component other than the indane mixture, the mole fraction of the indane or the indane mixture in the raw material composition is preferably 0.1 or more, and more preferably 0.2 or more. The upper limit of the molar fraction of indane or the indane mixture in the raw material composition is not particularly limited, but may be, for example, 0.95 or less, preferably 0.9 or less. By containing a component other than indan or an indan mixture, the dehydrogenation reaction tends to proceed easily and the decrease in the activity of the catalyst tends to be suppressed. However, since a large amount of energy is required to heat a component other than indane or an indane mixture, it is necessary to make an appropriate amount industrially. When the mole fraction of indane or an indane mixture in the raw material composition is within the above range, the energy required for the dehydrogenation reaction is further suppressed, and the indane can be efficiently dehydrogenated.

When molecular hydrogen is contained as the raw material composition, the molar ratio of molecular hydrogen to the indan or indan mixture (molecular hydrogen / indan or indan mixture) is preferably 10.0 or less in the raw material composition. It is more preferable that it is 7.0 or less. As a result, the influence of the thermodynamic equilibrium constraint is reduced, and the dehydrogenation reaction tends to proceed more efficiently. The molar ratio of molecular hydrogen to the indane or indane mixture in the raw material composition (molecular hydrogen / indane or indane mixture) is preferably 0.01 or more, more preferably 0.05 or more. As a result, the presence of molecular hydrogen can suppress the formation of cork on the catalyst, improve the durability of the catalyst, and obtain indene in a high yield.

When molecular hydrogen is contained as the raw material composition, the total content of the indane or the indane mixture and other compounds other than the molecular hydrogen is, for example, 10.0 times mol or less with respect to the indane or the indane mixture. It is preferably 5.0 times or less the molar amount of indane or an indane mixture, and may be 0.

<Dehydrogenation process>
In the dehydrogenation step, for example, a reactor filled with a zeolite catalyst may be used, and the dehydrogenation reaction may be carried out by flowing a raw material gas through the reactor. As the reactor, various reactors used for the gas phase reaction using a solid catalyst can be used. Examples of the reactor include a fixed bed adiabatic reactor, a radial flow reactor, a tubular reactor and the like.

The reaction type of the dehydrogenation reaction may be, for example, a fixed bed type, a moving bed type or a fluidized bed type. Of these, the fixed floor type is preferable from the viewpoint of equipment cost.

The temperature at which the raw material composition is brought into contact with the zeolite catalyst (which may also be the reaction temperature of the dehydrogenation reaction or the temperature inside the reactor) may be, for example, 350 to 800 ° C. from the viewpoint of reaction efficiency. , 400 to 700 ° C., and may be 450 ° C. to 650 ° C. When the reaction temperature is 350 ° C. or higher, the equilibrium conversion rate of indane or an indane mixture does not become too low, so that the yield of indene tends to be further improved. When the reaction temperature is 800 ° C. or lower, the rate of cork formation is suppressed, and the high activity of the zeolite catalyst can be maintained for a longer period of time.

The pressure at which the raw material composition is brought into contact with the zeolite catalyst (which can also be referred to as the reaction pressure of the dehydrogenation reaction or the pressure inside the reactor) may be, for example, 0.01 to 4.0 MPa, and may be 0. It may be 03 to 0.5 MPa, and may be 0.05 to 0.3 MPa. If the reaction pressure is within the above range, the dehydrogenation reaction tends to proceed easily, and a more excellent reaction efficiency tends to be obtained.

When the dehydrogenation step is carried out in a continuous reaction format in which the raw materials are continuously supplied, the mass space velocity (hereinafter, may be referred to as “WHSV”) may be 0.01 h ^-1 or more. It ^{may be 0.1h -1} or more. When the WHSV is equal to or higher than the above lower limit value, the conversion rate of indane can be further increased. Further, the WHSV may be 100h ^-1 or less, and may be ^{20h -1 or less.} When the WHSV is equal to or less than the above upper limit value, the reactor size can be further reduced. Here, WHSV is the ratio (F / W) of the supply rate (supply amount / hour) F of the raw material to the mass W of the zeolite catalyst in the continuous reactor. The amount of the raw material and the catalyst used may be appropriately selected in a more preferable range depending on the reaction conditions, the activity of the catalyst, and the like, and WHSV is not limited to the above range.

<Dehydrogenation process of tetrahydroindene>
The production method according to the present embodiment may further include a raw material synthesis step of obtaining indane or an indane mixture by a dehydrogenation reaction of tetrahydroindene.
It has a production method having a first dehydrogenation step of obtaining an indane mixture by dehydrogenating tetrahydroindene and a second dehydrogenation step of obtaining indene from the obtained indane mixture by a dehydrogenation reaction, that is, having tetrahydroindene. A production method for producing indene from a raw material is mentioned as a preferable production example according to the present embodiment.

The production conditions (conditions such as temperature and pressure) in the first and second dehydrogenation steps are not particularly limited and can be appropriately adjusted according to the purpose. The production conditions are not particularly limited, but for example, the production conditions in the first dehydrogenation step are relatively mild conditions, and the production conditions in the second dehydrogenation step are the first dehydrogenation step. It is preferable to manufacture under harsher conditions. Under the above production conditions, an indane mixture in which indane, octahydroindene and hexahydroindene are mixed in a suitable ratio is obtained in the first dehydrogenation step, and the indane mixture is used in the second dehydrogenation step. Indane tends to be produced efficiently and in high yield.
In the first dehydrogenation step, the temperature at which the raw material having tetrahydroindene is brought into contact with the dehydrogenation catalyst is not particularly limited, but may be, for example, 150 to 300 ° C.
In the first dehydrogenation step, the pressure at which the raw material having tetrahydroindene is brought into contact with the dehydrogenation catalyst is not particularly limited, but may be, for example, 0.01 to 5.0 MPa.
In the first dehydrogenation step, the WHSV is not particularly limited, but may be, for example, 0.1 to 10 h- ¹ .

As the dehydrogenation catalyst used in the first dehydrogenation step, a solid catalyst that catalyzes the dehydrogenation reaction of tetrahydroindene can be used without particular limitation. For example, the dehydrogenation catalyst, chromium / _Al 2 _{O 3} catalyst used as a catalyst for the dehydrogenation reaction, platinum / _Al 2 _{O 3} catalyst, Fe-K catalyst, platinum _/ SnO 2 _-Al 2 _{O 3} catalyst , Platinum-tin / magnesia alumina catalyst, Bi-Mo catalyst often used as a catalyst for oxidative dehydrogenation reaction, etc. can be used.

According to the production method having the first and second dehydrogenation steps, indene can be produced using an indane mixture in which indane, octahydroindene and hexahydroindene are mixed, and therefore indene can be produced from tetrahydroindene. Can be produced with high efficiency and high yield.

As a more specific production method, the downstream side of the reactor is filled with the above-mentioned zeolite catalyst, and the upstream side of the reactor is filled with a dehydrogenation catalyst for converting tetrahydroindene into indane or an indane mixture. Be done. Since the zeolite catalyst of the present embodiment is excellent in the reaction activity of the dehydrogenation reaction from indane or an indane mixture to indene, indene can be efficiently produced from tetrahydroindene according to the production method.

As described above, according to the production method according to the present embodiment, indene can be stably produced from a raw material composition containing indane in a high yield for a long period of time by using a specific zeolite catalyst. Can be done. As a result, the number of times of catalyst regeneration required for producing inden can be reduced and the production efficiency can be improved, which is very useful industrially.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the Examples.

[Catalyst synthesis example 1]
<Preparation of catalyst A>
(1) Aging step To the inside of a stainless steel pressure-resistant container, 4.0 g of tetraethyl orthosilicate (TEOS) and 4.6 g of a 20 to 25 wt% tetrapropylammonium hydroxide aqueous solution (TPAOH, organic structure defining agent) are added and sealed. Stirring (aging) was performed at 80 ° C. for 24 hours. The state of the mixture after stirring was liquid. TPAOH has been added as a regulator to build the zeolite structure and to make the aqueous solution basic. As a result, TEOS was polycondensed in the basic aqueous solution.

(2) Hydrothermal Synthesis Step A metal salt (zinc nitrate hexahydrate in this synthesis example) of a metal element (zinc in this synthesis example) to be introduced into the zeolite skeleton was dissolved in 0.5 g of ion-exchanged water.
Then, the mixture was added to the mixture obtained in the aging step, and the mixture was stirred at room temperature (25 to 30 ° C.) until homogenized. As a result, a gel in which silica and zinc ions coexist was obtained. The gelled mixture was placed in an oven, and hydrothermal synthesis was carried out at 175 ° C. for 24 hours while rotating at 20 rpm.

(3) Firing step The mixture after the hydrothermal synthesis step was put into a centrifuge tube and centrifuged to obtain a gel-like sample. Then, this gel-like sample was washed with ion-exchanged water.
For washing, ion-exchanged water was added to the gel-like sample for washing, and then centrifugation was performed. The pH of the supernatant after centrifugation was measured, and washing and centrifugation were repeated until the pH belonged to the range of 7 to 8.
The washed gel-like sample was dried in an oven at 90 ° C.
The dried sample was put into a muffle furnace and calcined at 550 ° C. for 8 hours in an air environment to obtain a zeolite catalyst. As a result, the tetrapropylammonium ion (cation), which is an organic substance in the zeolite, has been removed.

The following measurements were carried out on the obtained zeolite catalyst.
(A) Synchrotron XRD analysis XRD analysis was performed with a synchrotron XRD apparatus.
^{(B) Solid-state NMR analysis 29} Si MAS NMR measurement was performed by NMR (ECA-600, manufactured by JEOL Ltd.).
(C) FT-IR analysis Structural analysis was performed by FT-IR (FT / IR-4600, manufactured by JASCO Corporation). At this time, as a pretreatment, vacuum exhaust was performed at 450 ° C. for 1 hour.
_(D) CO 2 -TPD analyzer TPD analyzer (Microtrac Bell Co., BELCAT II) was _CO 2 -TPD analyzed by. About 30 mg of the zeolite catalyst was pretreated at 500 ° C. for 1 hour while flowing helium gas at a flow rate of 50 mL / min. Then, it was cooled to less than 40 ° C., 1 vol% CO ₂ / He gas was circulated at a flow rate of 50 mL / min _{to adsorb CO 2} on the zeolite catalyst, and then helium gas was circulated at a flow rate of 50 mL / min for 5 minutes. .. Then, while helium gas was circulated at 30 mL / min, the temperature was raised to 800 ° C. at a heating rate of 10 ° C./min, and CO ₂ desorption was analyzed by TCD (Thermal Conductivity Detector) and MASS. As MASS, BELMass manufactured by Microtrack Bell Co., Ltd. was used.
Measurement of amount of _base, was calculated from the peak area due to CO 2 -TPD.
_(E) NH 3 -TPD analyzer TPD analyzer (Microtrac Bell Co., BELCAT II) was _NH 3 -TPD analyzed by. About 30 mg of the zeolite catalyst was pretreated at 500 ° C. for 1 hour while flowing helium gas at a flow rate of 50 mL / min. Then, the mixture was cooled to 100 ° C., 1 vol% NH ₃ / He gas was circulated at a flow rate of 50 mL / min _{to adsorb NH 3} on a zeolite catalyst, and then helium gas was circulated at a flow rate of 50 mL / min for 15 minutes. Then, while helium gas was circulated at 30 mL / min, the temperature was raised to 700 ° C. at a heating rate of 10 ° C./min, _{and the withdrawal of NH 3} was analyzed by TCD and MASS. As MASS, BELMass manufactured by Microtrack Bell Co., Ltd. was used.
Measurement of the Lewis acid amount _was calculated from the peak area by NH 3 -TPD.

(A) Synchrotron XRD analysis The results of the synchrotron XRD analysis are shown in FIG. In the Zn-impregnated supported catalyst (a catalyst in which Zn is impregnated and supported on MFI-type zeolite having no metal introduced), a peak due to ZnO crystals was observed at the position indicated by the dotted line, but the zeolite in this example was observed. In the catalyst, no peak derived from ZnO crystals was observed.
(B) Solid-state NMR analysis ²⁹ The results of Si MAS NMR analysis are shown in FIG. When a zeolite composed of Si, O, and Zn is ^{measured by 29} Si MAS NMR, a peak appears at -110 to -120 ppm when the four bonds of Si atoms are only -O-Si, and four Si atoms are present. When at least one of the bonds is -O-Zn, a peak appears around -100 ppm ("Synthesis and Chemistry OF Zincosilicates with the SOD Topology" MA Camblor, RF Love, H. Koller, ME Davis, Chemistry of Materials, 6, P.2193-2199 (1994)). In the zeolite catalyst in this example, this peak of -100 ppm was observed.
(C) FT-IR analysis The result of FT-IR analysis at room temperature is shown in FIG. 3 after performing pretreatment by vacuum exhausting at 450 ° C. for 1 hour. If Zns are close to each other, they become Zn—O—Zn by pretreatment. ZnO crystals and Zn-impregnated supported catalysts do not have an absorption band in the region of ^{3600 to 3700 cm -1 in FT-IR analysis.} However, in the zeolite catalyst of this example, ^{an absorption band around 3640 cm -1} derived from the Zn-OH vibration of Zn is observed, and it is considered that the Zns are isolated from each other by being incorporated into the zeolite skeleton.
Further, after the pretreatment, the mixture was cooled to 150 ° C., pyridine was introduced, the temperature was raised to 250 ° C. while evacuating, and then FT-IR analysis was performed. The result is shown in FIG. In the presence of Bronsted acid, it is known that when pyridine is adsorbed on a zeolite catalyst and measured by FT-IR, an absorption band derived from the vibration of C ₆ H ₅ ^{N H is observed near 1560 cm -1.} There is. However, the absorption band was not found in the zeolite catalyst in this example.
In the presence of Lewis acid, it is known that an absorption band is observed in the vicinity of ^{1450 cm -1} when pyridine is adsorbed on a zeolite catalyst and measured by FT-IR. Then, in the zeolite catalyst of this example, an absorption band was observed in the vicinity of ^{1450 cm -1.} From this, it was found that the zeolite catalyst in this example does not have Bronsted acid and has only Lewis acid.
(D) CO _2- TPD _{analysis The results of CO 2-} TPD analysis are shown in FIG. In CO ₂ -TPD analysis, the zeolite catalyst comprising a common aluminum, while indicating the peak in the low temperature range around 100 ° C., no peak was observed in a high temperature range of not lower than 500 ° C.. Further, in the Zn-impregnated supported catalyst, a peak is observed only at around 100 ° C. However, in the zeolite catalyst of this example, a peak was observed even in a high temperature range of 500 ° C. or higher, confirming that the zeolite catalyst has strong solid basicity. Note _that solid base amount calculated from the peak area of the high temperature region of 500 ° C. or higher due to CO 2 -TPD was 0 ~ 0.035mmol / g.
(E) NH _3- TPD _{analysis The results of NH 3-} TPD analysis are shown in FIG. In the NH _3- TPD analysis, a broad peak was observed around 200 ° C. in the Zn-impregnated supported catalyst. Further, in the zeolite catalyst in this example, a large broad peak from 150 ° C. to 500 ° C. was observed. In FT-IR analysis, it was confirmed that the zeolite catalyst in this example did not have Bronsted acid and had only Lewis acid, so this peak was derived from the withdrawal of _{NH 3 adsorbed on Lewis acid.} It is thought that. The amount of acid calculated from the peak area was 0.01 to 0.2 mmol / g.

From the above results, it was confirmed that the obtained zeolite catalyst is a zeolite catalyst having an MFI structure, which does not have Bronsted acid but has only Lewis acid and has strong solid basicity.

(4) Platinum-supporting step Next, a dinitrodiamine platinum (II) nitric acid solution having a platinum content of 4.557 wt% with respect to 1 g of the calcined zeolite catalyst (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd., [Pt (NH ₃ ) ₂ (NO) ₂ ) ₂ ] / HNO ₃ ) 0.22 g was added, and platinum was impregnated and supported so that the amount of platinum supported was 1.0 wt%. Then, it was dried overnight at 130 ° C. and calcined in air at 550 ° C. for 3 hours to prepare catalyst A, which is a platinum-supported zeolite catalyst.

[Catalyst synthesis example 2]
<Preparation of catalyst B>
10 g of commercially available MFI-type zeolite (HZSM-5, SiO ₂ / Al ₂ O ₃ = 1500 (mol / mol), manufactured by Tosoh) was subjected to ion exchange at 50 ° C. in 250 mL of a 1 M sodium nitrate aqueous solution four times, and then at room temperature. Was washed with water. Then, it was dried overnight at 130 ° C. and calcined at 550 ° C. for 3 hours. Next, using a dinitrodiammine platinum (II) nitric acid solution (manufactured by Tanaka Kikinzoku Kogyo, [Pt (NH ₃ ) ₂ (NO ₂ ) ₂ ] / HNO ₃ ), platinum was supported so that the amount of platinum supported was 1.0 wt%. Was impregnated and supported, dried at 130 ° C. overnight, and calcined at 550 ° C. for 3 hours to prepare catalyst B.

[Catalyst synthesis example 3]
<Preparation of catalyst C>
10 g of commercially available MFI-type zeolite (HZSM-5, SiO ₂ / Al ₂ O ₃ = 40 (mol / mol), manufactured by Tosoh) was subjected to ion exchange at 50 ° C. in 250 mL of a 1 M sodium nitrate aqueous solution four times, and then at room temperature. Was washed with water and dried at 130 ° C. overnight. Subsequently, ion exchange was carried out four times again at 50 ° C. in 250 mL of an aqueous solution of 1M zinc nitrate hexahydrate, and then water washing was performed at room temperature. Then, it was dried overnight at 130 ° C. and calcined at 550 ° C. for 3 hours. Next, using a dinitrodiammine platinum (II) nitric acid solution (manufactured by Tanaka Kikinzoku Kogyo, [Pt (NH ₃ ) ₂ (NO ₂ ) ₂ ] / HNO ₃ ), platinum was supported so that the amount of platinum supported was 1.0 wt%. Was impregnated and supported, dried at 130 ° C. overnight, and calcined at 550 ° C. for 3 hours to prepare catalyst C.

[Catalyst synthesis example 4]
<Preparation of catalyst D>
Sodium hydroxide, tetraethyl orthosilicate (TEOS), tetrapropylammonium hydroxide (TPAOH), ethanol, and ion-exchanged water are mixed (TEOS: TPAOH: ion-exchanged water = 1: 0.12: 70 (mol ratio)). The prepared gel was stirred (aged) at 80 ° C. for 24 hours. The obtained mixture was hydrothermally synthesized at 175 ° C. for 24 hours and then repeatedly washed with water. Then, it was dried overnight at 130 ° C. and calcined at 550 ° C. for 3 hours. As a result, an aluminum-free silica light was obtained. The obtained silica light was confirmed to have an MFI structure by X-ray diffraction measurement (X-ray source: CuKα, apparatus: manufactured by Rigaku, RINT 2500).
Next, using a dinitrodiammine platinum (II) nitric acid solution (manufactured by Tanaka Kikinzoku Kogyo, [Pt (NH ₃ ) ₂ (NO ₂ ) ₂ ] / HNO ₃ ), platinum was supported so that the amount of platinum supported was 1.0 wt%. Was impregnated and supported, dried at 130 ° C. overnight, and calcined at 550 ° C. for 3 hours to prepare catalyst D.

[Catalyst synthesis example 5]
<Preparation of catalyst E>
To silicalite 1.25g obtained by the process of Catalyst Preparation Example 4, zinc nitrate hexahydrate (Kishida Chemical _{Ltd., Zn (NO 3) 2 ·} 6H 2 O) and 0.57g of water 0.71mL The dissolved aqueous solution was mixed, and zinc was impregnated and supported so that the final zinc content after the catalyst was prepared was 9.0 wt%. Then, it was dried overnight at 130 ° C. and calcined at 550 ° C. for 3 hours.
Next, using a dinitrodiammine platinum (II) nitric acid solution (manufactured by Tanaka Kikinzoku Kogyo, [Pt (NH ₃ ) ₂ (NO ₂ ) ₂ ] / HNO ₃ ), platinum was supported so that the amount of platinum supported was 1.0 wt%. Was impregnated and supported, dried at 130 ° C. overnight, and calcined at 550 ° C. for 3 hours to prepare catalyst E.

[Catalyst synthesis example 6]
<Preparation of catalyst F>
And commercial γ- alumina (manufactured by Sumitomo Chemical Co., Ltd.) 10.0 g, water magnesium nitrate hexahydrate (manufactured by Wako Pure Chemical Industries, _{Ltd., Mg (NO 3) 2 ·} 6H 2 O) and 12.5 g 100 mL Was mixed with the aqueous solution dissolved in. The obtained mixed solution was stirred at 50 ° C. for 180 minutes using an evaporator, and then water was removed under reduced pressure. Then, it was dried overnight at 130 ° C., calcined at 550 ° C. for 3 hours, and subsequently calcined at 800 ° C. for 3 hours. The resulting fired product and magnesium nitrate hexahydrate (manufactured by Wako Pure Chemical Industries, _{Ltd., Mg (NO 3) 2 ·} 6H 2 O) and 12.5g were mixed and an aqueous solution dissolved in water of 100 mL, an evaporator It was stirred at 50 ° C. for 180 minutes and then the water was removed under reduced pressure. Then, it was dried overnight at 130 ° C., calcined at 550 ° C. for 3 hours, and subsequently calcined at 800 ° C. for 3 hours. As a result, an alumina-magnesia carrier having a spinel-type structure was obtained. The obtained alumina-magnesia carrier was measured by X-ray diffraction measurement (X-ray source: CuKα, apparatus: Rigaku, RINT 2500), and 2θ = 36.9, 44.8, 59.4, 65.3 deg. A diffraction peak derived from Mg spinel was confirmed in.
Then, using a dinitrodiammine platinum (II) nitric acid solution (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd., [Pt (NH ₃ ) ₂ (NO ₂ ) ₂ ] / HNO ₃ ), the platinum content becomes 1.0 wt%. It was impregnated with platinum and supported, dried at 130 ° C. overnight, and calcined at 550 ° C. for 3 hours to prepare catalyst F.

[Manufacturing of Inden I]
Indene was produced using the catalysts A to F obtained in Catalyst Synthesis Examples 1 to 6.

(Example 1)
A tube reactor was filled with 1.0 g of catalyst A and the reaction tube was connected to a fixed bed flow reactor. The temperature of the reaction tube was raised to 500 ° C. while flowing molecular hydrogen at 30 mL / min and nitrogen at 30 mL / min, and then maintained for 1.0 h. Then, the raw materials indane, octahydroindene, hexahydroindene (indane: octahydroindene: hexahydroindene = 51: 5: 44 (wt%), indane mixture) and hydrogen are supplied to the reactor, respectively, and the reaction temperature is changed. The dehydrogenation reaction of the indane mixture was carried out at 500 ° C. and normal pressure. The composition supplied to the reactor was an indane mixture: hydrogen (H ₂ ) = 1.0: 3.0 (molar ratio). The WHSV was set to 3.0 h ^-1 .

When 2, 4 and 6 hours had passed from the start of the reaction, the product of the dehydrogenation reaction was collected from the tubular reactor. The reaction start time is the time when the supply of the raw material is started. The collected product was analyzed using a gas chromatograph (FID-GC) equipped with a hydrogen flame detector. Based on the gas chromatograph, each component (unit: wt%) of the collected reaction product was quantified, and the yield of indene was calculated. The results are shown in FIG.
Here, FIG. 9 is a graph showing the indene yield at the time when 2, 4 and 6 hours have passed from the start of the reaction in the indene production of Examples and Comparative Examples.

The indene yield is defined by the following formula (1).
rY = (m ₁ / m ₀ ) x 100 (1)
RY in the formula (1) is the indene yield (wt%). m ₀ is the total mass of the indane mixture present in the raw material. m ₁ is the mass of indene contained in the product.

(Comparative Example 1)
The procedure was the same as in Example 1 except that the catalyst B was used instead of the catalyst A. The results are shown in FIG.

(Comparative Example 2)
The procedure was the same as in Example 1 except that the catalyst C was used instead of the catalyst A. The results are shown in FIG.

(Comparative Example 3)
The procedure was the same as in Example 1 except that the catalyst D was used instead of the catalyst A. The results are shown in FIG.

(Comparative Example 4)
The procedure was the same as in Example 1 except that the catalyst E was used instead of the catalyst A. The results are shown in FIG.

(Comparative Example 5)
The procedure was the same as in Example 1 except that the catalyst F was used instead of the catalyst A. The results are shown in FIG.

(Example 2)
When 2, 4 and 6 hours have passed from the start of the reaction, the product of the dehydrogenation reaction was collected from the tubular reactor, and from the start of the reaction to 24 hours, every 2 hours. The same procedure as in Example 1 was carried out except that the product of the dehydrogenation reaction was collected from a tubular reactor. The results are shown in FIG.
FIG. 10 is a graph showing the indene yield from the start of the reaction to 24 hours in the indene production of Examples and Comparative Examples.

(Comparative Example 6)
When 2, 4 and 6 hours have passed from the start of the reaction, the product of the dehydrogenation reaction was collected from the tubular reactor, and from the start of the reaction to 24 hours, every 2 hours. , The same procedure as in Comparative Example 5 was carried out except that the product of the dehydrogenation reaction was collected from the tubular reactor. The results are shown in FIG.

Here, Examples 1 and 2 are experimental examples showing the indene yield using a zeolite catalyst in which a transition metal is introduced into the zeolite skeleton.
As a comparative example, a transition metal is not introduced in the zeolite skeleton and the aluminum content is small (Comparative Example 1), and a transition metal is not introduced in the zeolite skeleton and the aluminum content is high. A large zeolite catalyst (Comparative Example 2), a catalyst using silicalite as a carrier (Comparative Example 3), a catalyst using a silicalite as a carrier impregnated with a transition metal (Comparative Example 4), and an alumina having a spinel-type structure. For catalysts using magnesia as a carrier (Comparative Examples 5 and 6), the inden yield was determined by a method similar to that of Examples.

As shown in FIG. 9, when the reaction was carried out using the zeolite catalyst in which the transition metal was introduced into the zeolite skeleton of Example 1, the catalyst in which the transition metal was not introduced into the skeleton of Comparative Examples 1 to 5 was carried out. It was confirmed that the inden yield was higher than that of the above.
Further, in the catalysts of Comparative Examples 1 to 5, the indene yield decreased with the lapse of the reaction time, but it was confirmed that the catalyst of Example 1 showed stable indene formation with the lapse of the reaction time. ..
Further, as shown in FIG. 10, a high indene yield was maintained even after the reaction with the catalyst of Example 2 for 24 hours, and it was confirmed that the catalyst of Example 2 had a remarkably long catalyst life.

[Manufacturing of Inden II]
A raw material containing indan using a fixed-bed flow reactor, two tubular reactors connected in series, using tetrahydroinden as a raw material, and using a catalyst for the first dehydrogenation step described later on the upstream side of the reactor. The composition was obtained (first dehydrogenation step), and inden was produced (second dehydrogenation step) using the catalyst A obtained in Catalyst Synthesis Example 1 on the downstream side of the reactor.

(Example 3)
<Preparation of catalyst for the first dehydrogenation process>
To commercial γ- alumina (Sumitomo Chemical Co., Ltd.) 10.0 g, Sodium stannate (Kishida Chemical Co., _{Ltd., Na 2 SnO 3 · 3H 2} O) an aqueous solution prepared by dissolving 6.1g of water 60ml mixing did. The obtained mixed solution was stirred at 50 ° C. for 120 minutes using an evaporator, and then water was removed under reduced pressure. Then, it was dried overnight at 130 ° C., calcined at 550 ° C. for 3 hours, and then repeatedly washed with water to obtain an alumina-tin oxide carrier.
Using a dinitrodiammine platinum (II) nitric acid solution (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd., [Pt (NH ₃ ) ₂ (NO ₂ ) ₂ ] / HNO ₃ ) on the above alumina-tin oxide carrier, the platinum content is 1. Platinum was impregnated and supported so as to be 0.0 wt%, dried at 130 ° C. overnight, and calcined at 550 ° C. for 3 hours to obtain a catalyst for the first dehydrogenation step.

<Dehydrogenation reaction related to the first and second dehydrogenation steps>
Two tubular reactors are connected in series, 1.0 g of the dehydrogenation catalyst for the first dehydrogenation step is applied to the upstream side (first stage) of the reactor, and the downstream side (second stage) of the reactor. Was filled with 1.0 g of catalyst A, and the reaction tube was connected to a fixed bed flow reactor. After heating the temperature of the first-stage reaction tube to 180 ° C and the second-stage reaction tube to 500 ° C while flowing molecular hydrogen at 30 mL / min and nitrogen at 30 mL / min from the first-stage inlet, 1. It was held for 0 h, and the hydrogen pretreatment of the catalyst was completed.
Tetrahydroindene (3a, 4,7,7a-tetrahydroindene; manufactured by Tokyo Chemical Industry Co., Ltd.) was used as a raw material and supplied at 3.0 g / h from the first stage entrance. The reaction temperature of the first stage was 180 ° C., the reaction pressure was 0.9 MPa, no diluting gas such as hydrogen or nitrogen was used, and only the raw materials were supplied (first dehydrogenation step). The product oil of the first stage is supplied as it is to the second stage, the reaction temperature of the second stage is set to 500 ° C., the reaction pressure is set to normal pressure, and molecular hydrogen is added from the inlet of the second stage in an amount three times as much as that of tetrahydroinden. Then, the reaction was carried out to produce an inden (second dehydrogenation step). The reaction was carried out for 12 hours, and the first-stage outlet composition and the second-stage outlet composition were measured every 2 to 3 hours.

For 12 hours, the first-stage outlet composition was stable at 52 wt% for indene, 1 wt% for indene, 6 wt% for octahydroindene, 40 wt% for hexahydroindene, and 1 wt% for unidentified material. The raw material tetrahydroindene was not detected at the exit of the first stage, and the conversion rate was 100%. The time course of indene and hexahydroindene at the exit of the second stage is shown in FIG. For 12 hours, the composition of the first-stage outlet was stable, and the indene yield of the second-stage outlet was also stable. Since hexahydroindene was significantly reduced and indene was generated at the second stage reaction outlet, it is considered that hexahydroindene is easily dehydrogenated and contributes to the improvement of indene yield.

This application claims priority based on Japanese Patent Application No. 2019-233192, which is a Japanese patent application filed on December 24, 2019, and incorporates all the contents of the Japanese patent application.

Claims (7)

1. A dehydrogenation step is provided in which the raw material composition containing indane is brought into contact with a zeolite catalyst having an MFI structure to obtain a reaction product containing indene.
   The zeolite catalyst contains at least one metal atom selected from a transition metal or a post-transition metal in the zeolite skeleton, and has Lewis acidity and strong solid basicity.
   Indene manufacturing method.
2. The inden according to claim 1, wherein the metal atom is one or more selected from Zn atom, Fe atom, and Ni atom, and the content of the metal atom is 1 to 15 atom% with respect to the Si atom. Manufacturing method.
3. The method for producing an inden according to claim 1 or 2, wherein the zeolite catalyst does not contain an alkali metal or contains 1 atom% or less of an alkali metal with respect to the Si atom of the zeolite skeleton.
4. The method for producing indene according to any one of claims 1 to 3, wherein the zeolite catalyst is supported by a Pt atom.
5. The method for producing indene according to any one of claims 1 to 4, wherein the raw material composition further contains at least one of octahydroindene and hexahydroindene.
6. The method for producing indene according to any one of claims 1 to 5, wherein the raw material composition further contains molecular hydrogen.
7. The method for producing indene according to any one of claims 1 to 6, further comprising a raw material synthesis step of obtaining indane by a dehydrogenation reaction of tetrahydroindene.
   
   

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