JP6862966B2 - Metal-containing zeolite - Google Patents

Description

The present invention relates to a novel metal-containing zeolite, and more specifically, it contains a specific metal suitable for hydrocarbon conversion and isomerization, and has an acid point on the surface having an average particle size of 100 nm or less. Not related to novel metal-containing zeolites.

Medium-pore zeolite is used as a highly selective catalyst utilizing pores of a size equivalent to that of an aromatic compound. Examples of using MFI-type zeolite as a catalyst, which is a typical medium-pore zeolite, include toluene disproportionation (see, for example, Patent Document 1), xylene isomerization (see, for example, Patent Document 2), and aliphatic. Aromatization of hydrocarbons (see, for example, Patent Document 3) and the like can be mentioned. These reactions mainly utilize the characteristics of the micropores of medium-pore zeolite. The micropores of the medium-pore zeolite have an inlet diameter of about 0.5 nm, and are considered to be an effective reaction field for molecules having a molecular diameter close to the pore diameter.

In particular, in the aromatization of hydrocarbons, efforts have been made to improve the activity and selectivity of zeolite by containing a metal. For example, as a catalyst for producing an aromatic compound using a hydrocarbon containing paraffin, olefin, and naphthene as a raw material, a zinc-supported intermediate pore size zeolite-based catalyst in which the amount of zinc scattering is suppressed is provided (for example, Patent Document 4). reference.). Further, as a catalyst used for producing an aromatic compound using paraffin, olefin, acetylene hydrocarbon, cyclic paraffin and cyclic olefin as raw materials, a catalyst obtained by simultaneously supporting platinum and halogen components on L-type zeolite is provided. (See, for example, Patent Document 5). Furthermore, the structure has a size of 0.1 to 100 mm, crystalline porous aluminosilicate is present on the surface layer of the structure, and an inorganic support is present on the inner layer excluding the surface layer of the structure. Provided is a catalyst for an aromatization reaction characterized by carrying zinc and / or gallium on the body (see, for example, Patent Document 6). In addition, catalysts for producing aromatic compounds using hydrocarbons as raw materials are provided (see, for example, Patent Documents 7 and 8).
On the other hand, non-selective reactions at the acid points on the zeolite surface are generally undesirable. These non-selective reactions often lead to reduced product yields, reduced product selectivity, and catalyst deactivation due to cork precipitation.

Therefore, in order to suppress an undesired reaction on the zeolite surface, a method has been proposed in which the aluminum on the surface is extracted with a bulky reagent or the surface is coated to reduce or eliminate the acid spots on the surface.

Then, a method for producing a zeolite having a reduced acidity on the outer surface by coating a zeolite having an MFI structure with a silicate and a method for selectively producing p-xylene by the production has been proposed (see, for example, Patent Document 9). .).

Further, a method of reducing the surface acidity by coating the surface acidity of zeolite with a bulky dialkylamine reagent has been proposed (see, for example, Patent Documents 10 and 11).

Japanese Patent No. 401479 Japanese Patent No. 2598127 Japanese Patent No. 2905947 JP-A-1998-33987 Japanese Patent No. 3264447 Japanese Patent No. 5447468 Japanese Patent No. 3966429 Japanese Patent No. 5564769 Japanese Patent No. 6029654 U.S. Pat. No. 4,502,221 U.S. Pat. No. 4,568,768

However, in the method for producing an aromatic compound using the catalytic reaction proposed in Patent Documents 4 to 8, from the viewpoint of production cost, the catalyst life (from the active state of the catalyst after the start of the reaction to the deactivation of the catalyst) Had a problem in time).

Then, in the coating of the surface acid spot with the amine proposed in Patent Documents 10 and 11, there is a problem that the amine is desorbed or decomposed at a high temperature. Further, in the method of coating zeolite with silicate, which is proposed in Patent Document 9, there is a problem that hydrothermal synthesis is required a plurality of times for coating. As a relatively easy method for removing acid spots without these problems, desorption of aluminum by water vapor can be mentioned, but in general, only aluminum on the zeolite surface can be selectively removed by this method. However, even the aluminum in the pores was removed, which also led to a decrease in the acidity in the pores.

On the other hand, the zeolite of the present invention has substantially no acid point on the surface and has an acid point only in the pores by selectively removing aluminum on the surface of the zeolite, and is further specified therein. By containing the above metal, it is possible to achieve high activity, long life, and high selectivity in, for example, hydrocarbon conversion reaction and isomerization reaction, and it is possible to provide zeolite highly useful in petrochemistry. is there.

As a result of diligent studies to solve the above problems, the present inventors have found a novel metal-containing zeolite containing a specific metal and having specific properties, and have completed the present invention.

That is, the present invention is characterized in that it contains at least one metal selected from Groups 6 to 10 and 12 to 13 of the Periodic Table and has the following characteristics (i) to (iv). It relates to a metal-containing zeolite to be used.
(I) The average particle size (hereinafter referred to as PD) is PD ≦ 100 nm.
(Ii) The skeletal structure is a 10-membered ring structure.
(Iii) Has no acid spot on the surface.
(Iv) The amount of acid is 0.05 to 0.85 mmol / g.

Hereinafter, the present invention will be described in detail.

The metal-containing zeolite of the present invention is a metal-containing zeolite having the characteristics (i) to (iv) and containing at least one metal selected from Groups 6 to 10 and 12 to 13 of the Periodic Table. is there.

At least one metal selected from Groups 6 to 10 and 12 to 13 of the Periodic Table at this time is, for example, at least selected from molybdenum, manganese, iron, cobalt, nickel, palladium, platinum, zinc and gallium. One type of metal can be mentioned, and it should be selected from nickel, zinc, molybdenum, iron and gallium because it exhibits excellent properties and durability especially during conversion and isomerization. Is preferable. The content thereof is preferably 0.05 to 5 wt%.

The metal-containing zeolite of the present invention has (i) PD ≦ 100 nm. In particular, since it is excellent in thermal stability, it is desirable that 3 nm ≦ PD ≦ 100 nm, and further preferably 5 nm ≦ PD ≦ 100 nm. Here, if the PD exceeds 100 nm, the reaction efficiency will be inferior when used in the conversion / isomerization reaction of hydrocarbons.

PD can be calculated from the outer surface area of zeolite, for example, by using the following formula (1).
PD = 6 / S (1 / 2.29 × 10 ⁶ + 0.18 × ^10-6 ) (1)
(Here, S indicates the outer surface area (m ² / g).)
Further, the outer surface area (S (m ² / g)) in the formula (1) can be obtained from the t-prot method using a general nitrogen adsorption method at a liquid nitrogen temperature. For example, when t is the thickness of the adsorption amount, the measurement points in the range of 0.6 to 1 nm are linearly approximated with respect to t, and the outer surface area of the zeolite is obtained from the slope of the obtained regression line.

Further, the metal-containing zeolite has a (ii) skeleton structure having a 10-membered ring structure. Examples of zeolite having a 10-membered ring skeleton structure include zeolites of AEL, EUO, FER, HEU, MEU, MEL, MFI, NES type, etc. Among them, aliphatic hydrocarbon conversion reaction / isomerization reaction. MFI, FER, and MEL type zeolites are preferable, and MFI type zeolites are particularly preferable.

The metal-containing zeolite is one that does not have an acid point on the (iii) surface.

Here, the surface acid point of zeolite, as the word means, indicates the acid point existing on the surface of zeolite. Normally, zeolite has an acid point on its surface and in (micro) pores, and having no acid point on the surface can be said to have an acid point only in (micro) pores. Is. Since the zeolite is particularly excellent in heat resistance, heat resistance and water resistance, and durability, it is preferable that the zeolite has an unmodified surface whose surface is not coated with a silicate, a dialkylamine reagent or the like.

As for the confirmation of the acid point on the surface of the zeolite (the absence of the acid point on the surface), any method can be used as long as the confirmation can be performed, for example, the adsorptivity to the acid point. It can be confirmed by adsorption of 2,4-dimethylquinoline having (Charactration of acid systems on the external surfactants of zeolites, Reaction Kinetics and Catalyst Letters, vol. 67, p. 281). 2,4-Dimethylquinoline has an acid point (-OH) and adsorption properties existing on the zeolite surface (including the inner surface of the pores), but the (micro) pore diameter of the zeolite is 2,4-dimethyl. If it is smaller than the quinoline molecule, it cannot penetrate into the (micro) pores and cannot adsorb to the acid points in the (micro) pores. That is, it is adsorbed only with the acid point on the zeolite surface. Therefore, when the adsorption of 2,4-dimethylquinoline on the acid point (−OH) existing on the surface of the zeolite is not observed, it can be determined that the acid point does not exist on the surface of the zeolite.

As a more specific method, infrared absorption spectrum measurement at 150 ° C. of zeolite which has been degassed and dehydrated at 400 ° C. for 2 hours as a pretreatment of zeolite is performed. Then, 2,4-dimethylquinoline gas is introduced into the degassed / dehydrated zeolite and adsorbed for 10 minutes, and excess 2,4-dimethylquinoline is removed by exhaust at 150 ° C. to remove 2,4-dimethylquinoline. The adsorbed zeolite is prepared and the infrared absorption spectrum is measured at 150 ° C. That is, in the infrared absorption difference spectrum before and after 2,4-dimethylquinoline adsorption, if the difference (decrease) in infrared absorption cannot be confirmed in the range of ^{3600 to 3650 cm -1, it is judged that there is no acid spot on the surface.} Can be done. Although 2,4-dimethylquinoline is also adsorbed on the silanol site on the zeolite surface, absorption derived from the oh expansion and contraction vibration of silanol is observed at ^{3700 to 3800 cm -1.} On the other hand, the absorption derived from the OH expansion and contraction vibration of the acid point on the zeolite surface ^{was observed at 3600 to 3650 cm -1,} and the absorption derived from the OH expansion and contraction vibration of the acid point by adsorbing 2,4-dimethylquinoline was observed. A decrease in the infrared absorption spectrum in the range of 3600 to 3650 cm ^-1 indicates that 2,4-dimethylquinolin was adsorbed on the surface acid point of the zeolite.

The metal-containing zeolite has an (iv) acid content of 0.05 to 0.85 mmol / g, preferably 0.05 to 0.55 mmol / g. Here, when the zeolite has an acid content of more than 0.85 mmol / g, coke easily adheres to the zeolite when it is used for the conversion / isomerization reaction of hydrocarbons, and the conversion / isomerization reaction is deactivated faster. When the amount of acid is less than 0.05 mmol / g, the activity of the zeolite during the conversion / isomerization reaction of the hydrocarbon is low. The amount of acid in the zeolite referred to in the present invention is basically the amount of acid in the (micro) pores because it does not have an acid point on the (iii) surface. Is.

The amount of acid can be measured by using a method generally known as a method for measuring the amount of acid. For example, the ammonia-TPD method (measurement of solid acid properties by ammonia temperature desorption method, catalyst) , Vol. 42, p. 218 (2000).). Specifically, ammonia is saturated and adsorbed on zeolite at room temperature, heated to 100 ° C. to remove ammonia remaining in the measurement atmosphere, and then the temperature rise process to 700 ° C. at a heating rate of 10 ° C./min. Among the peaks of ammonia measured in (1), the amount of ammonia desorbed on the high temperature side indicating the strong acid point can be used as the solid acid amount.

Further, the metal-containing zeolite _{may be any as long as it belongs to the category called zeolite as its SiO 2} / Al ₂ O ₃ ratio, and above all, it is used for the conversion / isomerization reaction of hydrocarbons. When used, the efficiency is excellent, so that the SiO ₂ / Al ₂ O ₃ ratio = 20 to 300 is preferable, and the heat resistance, reaction selectivity, and productivity are particularly excellent. , SiO ₂ / Al ₂ O _{3 ratio = 30 to} 200 is preferable.

The metal-containing zeolite can be made by using zeolite having the following characteristics (v) to (viii) as a base material and containing a metal. As a production method at that time, for example, the following (v) Examples thereof include a method of introducing a metal into a zeolite having the characteristics of to (viii) by impregnation support, ion exchange, skeleton substitution, or the like.
(V) PD ≦ 100 nm.
(Vi) The skeletal structure is a 10-membered ring structure.
(Vii) There are no acid spots on the surface.
The amount of (viii) acid is 0.1 to 1.0 mmol / g.

The zeolite used as the base material at that time is (v) PD ≦ 100 nm. In particular, since the metal-containing zeolite is excellent in thermal stability, it is desirable that 3 nm ≦ PD ≦ 100 nm, and further preferably 5 nm ≦ PD ≦ 100 nm. The PD can be calculated and obtained by using the above method, that is, the above equation (1).

Further, the base zeolite has a (vi) skeletal structure having a 10-membered ring structure. Examples of zeolite having a 10-membered ring skeleton structure include zeolites of AEL, EUO, FER, HEU, MEU, MEL, MFI, NES type and the like, and among them, suitable for hydrocarbon conversion reaction and isomerization reaction. MFI, FER, and MEL type zeolites are preferable, and MFI type zeolites are particularly preferable.

Further, the base zeolite is one that does not have an acid point on the (vii) surface. Then, as the confirmation of the acid point on the surface of the zeolite (the absence of the acid point on the surface), the above-mentioned method can be mentioned.

The base zeolite has a (viii) acid amount of 0.1 to 1.0 mmol / g, preferably 0.1 to 0.6 mmol / g. Since the acid amount in the zeolite as the base material does not have an acid point on the (vii) surface, it is basically the acid amount of the acid point in the (micro) pores. Is. As the measurement of the amount of acid, the above-mentioned method can be mentioned.

As a method for producing the base zeolite, any method can be used as long as the zeolite having the characteristics described in (v) to (vi) above can be produced. Then, as a method for selectively removing the acid spots on the surface of the zeolite, that is, the zeolite having no acid spot on the surface, a firing (heat treatment) step for producing the zeolite having the characteristics (v) to (vi). A method in which a part or all of the above is used as a water heat (steam) treatment step and an ion exchange step is added before and after the firing step can be mentioned.

As a method for synthesizing a zeolite that satisfies the characteristics (v) to (vi), a generally known method is used to obtain a zeolite having a PD ≦ 100 nm and a 10-membered ring skeleton structure. Specifically, it can be produced by mixing a compound containing an alkali metal and / or an alkaline earth metal as a cation, an organic structure-directing agent and an aluminosilicate gel, and calcining the obtained crystal. .. Examples of the compound containing an alkali metal and an alkaline earth metal at that time include sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide and the like, and sodium hydroxide is particularly preferable. Examples of the organic structure-directing agent include tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, and tetraethylammonium hydroxide. Further, as the aluminosilicate gel, for example, an amorphous aluminosilicate gel can be mentioned.

Further, in the case of producing zeolite having the characteristics (v) to (viii), ion exchange is performed before firing the crystal obtained as described above, and a part or all of the firing is subjected to a hydrothermal treatment step. After that, it becomes possible to carry out the production by a method of further ion exchange.

As the firing conditions at that time, the treatment temperature is preferably 300 to 900 ° C, particularly preferably 400 to 700 ° C. The treatment time is industrially preferably 10 minutes to 40 hours. The atmosphere may also include, for example, nitrogen, air, oxygen, argon, or any other combination of one or more of the inert gases. Then, by performing a hydrothermal (steam) treatment on a part or all of the firing step, the aluminum at the proton acid point is desorbed. The treatment temperature of the hydrothermal treatment is preferably 400 to 750 ° C, particularly preferably 500 to 650 ° C. The water vapor concentration is preferably 10 to 100%, particularly preferably 40 to 90%.

Further, the ion exchange is performed before and after the firing step, and may be divided into a plurality of times of ion exchange. Further, the ion exchange includes ion exchange using an acid such as ammonium chloride, hydrochloric acid and nitric acid, and those using hydrochloric acid and nitric acid are preferable. In addition, ion exchange can be replaced by washing with water.

The metal-containing zeolite of the present invention is suitable as a catalyst that exhibits high activity, high selectivity, and long life in hydrocarbon conversion reactions and isomerization reactions. For example, by using the metal-containing zeolite as a catalyst for producing an aromatic compound, it becomes a catalyst having excellent efficiency such as reaction selectivity and productivity. For example, aliphatic hydrocarbons, particularly aliphatic hydrocarbons having 10 or less carbon atoms. By contacting with hydrogen and further, an aliphatic hydrocarbon having 2 to 6 carbon atoms, it is possible to efficiently produce an aromatic compound. Examples of the aliphatic hydrocarbon at that time include those including paraffin-based, olefin-based, acetylene-based, and alicyclic hydrocarbons, and specifically, ethane, propane, butene, isobutane, pentane, and the like. Paraffin-based compounds such as hexane; olefin-based compounds such as ethylene, propylene, butene, isobutene, pentene, and hexene; acetylene-based compounds such as acetylene; alicyclic compounds such as cyclopropane, cyclobutane, and cyclohexane, and mixtures thereof.

The present invention relates to a novel metal-containing zeolite having microcrystalline medium pore zeolite from which surface acid spots have been removed and containing a specific metal. A metal-containing zeolite having such unique properties can be expected as a catalyst having high activity, long life, and high selectivity in, for example, a hydrocarbon conversion reaction or an isomerization reaction.

Hereinafter, specific examples of the present invention will be described as examples, but the present invention is not limited to these examples.

~ Measurement of outer surface area of zeolite ~
The outer surface area of zeolite was measured by nitrogen adsorption measurement.

As the nitrogen adsorption measurement, a nitrogen adsorption device ((trade name) Belsorb-max, manufactured by Microtrac Bell Co., Ltd.) was used, and both adsorption and desorption were measured under the condition of 40 torr / step. The outer surface area was determined by linearly approximating the range of the thickness (t = 0.6 to 1.0 nm) of the adsorption layer by the t-prot method.

~ Measurement of average particle size ~
The average particle size was calculated from the outer surface area of the zeolite using the above formula (1). In formula (1), S is the outer surface area (m ² / g) and PD is the average particle size (m).

~ SiO ₂ / Al ₂ O ₃ ratio, measurement of metal content ~
The SiO ₂ / Al ₂ O ₃ molar ratio and metal content of the zeolite are determined by dissolving the zeolite in a mixed aqueous solution of hydrofluoric acid and nitric acid and using a general ICP device ((trade name) OPTIMA3300DV, manufactured by PerkinElmer). It was measured and determined by inductively coupled plasma emission spectroscopy (ICP-AES).

~ 2,4-Dimethylquinoline adsorption infrared absorption spectroscopy ~
Infrared absorption spectroscopy is measured by using a general FT-IR measuring device ((trade name) Varian 660-IR, manufactured by Agilent Technologies, Inc.) and parts for IR measuring device under vacuum ((trade name) multi-mode cell). , ST Japan) was used in combination. The sample was disc-molded, placed in a cell, heated to 400 ° C. at 10 ° C./min under vacuum exhaust, and held for 2 hours. After cooling to 150 ° C., the infrared absorption spectrum before adsorption of 2,4-dimethylquinoline was measured. 2,4-Dimethylquinoline gas was introduced, adsorbed for 10 minutes, evacuated at 150 ° C. for 1 hour, and then the infrared absorption spectrum after adsorbing 2,4-dimethylquinoline was measured. The difference between the infrared absorption spectrum after adsorption of 2,4-dimethylquinoline and the spectrum before adsorption was taken, and the change in infrared absorption due to adsorption was measured.

~ How to measure the amount of acid ~
_{A general NH 3-} TPD device ((trade name) BELCATII, manufactured by Microtrack Bell Co., Ltd.) and a gas analyzer ((trade name) BELMass, manufactured by Microtrack Bell Co., Ltd.) were used to measure the amount of acid. .. The sample was granulated, placed in a cell, heated to 500 ° C. at 10 ° C./min under a helium atmosphere, and held for 1 hour. Then, the temperature was lowered to 100 ° C., and 0.2% ammonia gas was introduced for 30 minutes. The temperature was raised to 600 ° C. at 10 ° C./min, and the desorbed ammonia was analyzed with a gas analyzer. The acid amount of the sample was calculated from the remaining desorption amount excluding the desorption amount derived from the weak acid.

~ Aromatic compound manufacturing equipment and its manufacturing method ~
As the reaction device, a fixed bed gas phase flow type reaction device using a stainless steel reaction tube (inner diameter 16 mm, length 300 mm) was used. The middle stage of each stainless steel reaction tube was filled with a catalyst for producing an aromatic compound, pretreated by heating under a dry air flow, and then the raw material gas was fed. The apparatus conditions and operating conditions of the reactor are not limited to the conditions described in this embodiment, and can be appropriately selected. Then, a ceramic tube furnace was used for heating, and the temperature of the catalyst layer was controlled. The reaction outlet gas and the reaction solution were collected, and the gas component and the liquid component were analyzed individually using a gas chromatograph. The gas component was analyzed using a gas chromatograph equipped with a TCD detector (manufactured by Shimadzu Corporation, (trade name) GC-1700). As the filler, Waters Corp. PorapakQ (trade name) or GL Science Co., Ltd. MS-5A (trade name) was used. The liquid components were analyzed using a gas chromatograph equipped with a FID detector (manufactured by Shimadzu Corporation, (trade name) GC-2015). As the separation column, a capillary column (manufactured by GL Science Co., Ltd. (trade name) TC-1) was used.

The reaction conditions were set as follows.

(Aromatic compound production conditions)
Catalyst temperature: 550 ° C
Distribution gas: Mixed gas of 50 mol% of raw material hydrocarbon + 50 mol% of nitrogen, 60 ml / min.
Raw Hydrocarbon: 1-Ratio of raw material hydrocarbon volume to butene catalyst volume: 1000 / hour.
Catalyst weight: 0.9 g.
Catalyst shape: The metal-containing zeolite powder was ^{molded at 400 kgf / cm 2} for 1 minute and then pulverized to obtain a pellet shape of about 1 mm.
Reaction pressure: 0.1 MPa.

Preparation Example 1
Atypical aluminosilicate gel was added to an aqueous solution of tetrapropylammonium (hereinafter sometimes abbreviated as TPA) hydroxide and sodium hydroxide and suspended. MFI-type zeolite was added as a seed crystal to the obtained suspension to prepare a raw material composition. The amount of the seed crystal added at that time was 0.7% by weight with respect to the weight _{of Al 2} O ₃ and SiO _{2 in the raw material composition.} In addition, the by-produced ethanol was removed by evaporation.

The composition of the raw material composition is as follows.
SiO ₂ / Al ₂ O ₃ molar ratio = 44, TPA / Si molar ratio = 0.05, Na / Si molar ratio = 0.16, OH / Si molar ratio = 0.21, H ₂ O / Si molar ratio = 10
The obtained raw material composition was sealed in a stainless steel autoclave and crystallized for 4 days with stirring at 115 ° C. to obtain a slurry-like mixed solution. The slurry-like mixed solution after crystallization was solid-liquid separated by a centrifugal sedimentation machine, and then the solid particles were washed with a sufficient amount of pure water and dried at 110 ° C. to obtain a dry powder.

The obtained dry powder was dispersed in 1 mol / L hydrochloric acid, filtered and dried. After firing in air at 550 ° C. for 1 hour, it was treated with 60 ° C. and 80% steam for 2 hours.

The obtained powder was dispersed in 1 mol / L hydrochloric acid, filtered and dried to obtain an MFI-type zeolite.

The obtained MFI-type zeolite had a 10-membered ring skeleton structure, an average particle size of 40 nm, a SiO ₂ / Al ₂ O ₃ molar ratio of 68, and an acid content of 0.23 mmol / g.

The difference spectrum of infrared absorption before and after adsorbing 2,4-dimethylquinoline on the obtained MFI-type zeolite is shown in FIG. Peak derived from OH zeolite acid sites of 3605cm ^-1 is not reduced, the peak derived from OH of silanol 3700～3800Cm ^-1 decreased significantly. Therefore, it was confirmed that 2,4-dimethylquinoline was adsorbed only on silanol on the surface of the zeolite, and no acid spot was present on the surface of the zeolite.

Example 1
The MFI-type zeolite obtained in Preparation Example 1 was supported by a metal by an ion exchange method. 0.32 g (0.31 mmol) of gallium nitrate pentahydrate was dissolved in 300 ml of distilled water, and 3 g of the MFI-type zeolite obtained above was added to 100 m of the aqueous solution to prepare a slurry solution, which was stirred in a water bath at 45 ° C. for 2 hours. .. After filtering with a Büchner funnel, 100 ml of a gallium nitrate pentahydrate aqueous solution was added again, and the mixture was stirred in the same manner. After repeating 3 times, the filtered zeolite was dried at 110 ° C. overnight and calcined at 550 ° C. for 4 hours to obtain a gallium-containing MFI-type zeolite.

The obtained gallium-containing MFI-type zeolite contains 0.62 wt% of gallium. It had a 10-membered ring skeleton structure, an average particle size of 40 nm, a SiO ₂ / Al ₂ O ₃ molar ratio of 68, no acid spots on the surface, and an acid content of 0.20 mmol / g.

Example 2
A zinc-containing MFI-type zeolite was obtained by the same method as in Example 1 except that 0.04 g (0.12 mmol) of zinc nitrate hexahydrate was used instead of 0.32 g of gallium pentahydrate. ..

The obtained zinc-containing MFI-type zeolite contains 0.93 wt% of zinc, has a 10-membered ring skeleton structure, has an average particle size of 40 nm, a SiO ₂ / Al ₂ O ₃ molar ratio of 68, and has no acid spot on the surface. The acid content was 0.24 mmol / g.

Example 3
A nickel-containing MFI-type zeolite was obtained in the same manner as in Example 1 except that 0.20 g (0.68 mmol) of nickel nitrate hexahydrate was used instead of 0.32 g of potassium nitrate pentahydrate.

The obtained nickel-containing MFI-type zeolite contains 0.80 wt% of nickel, has a 10-membered ring skeleton structure, has an average particle size of 40 nm, a SiO ₂ / Al ₂ O ₃ molar ratio of 68, and has no acid spot on the surface. The acid content was 0.25 mmol / g.

Example 4
The MFI-type zeolite obtained in Preparation Example 1 was supported by a metal by an impregnation method. 3 g of the MFI-type zeolite obtained above was placed in a mortar. Therefore, an aqueous solution prepared by dissolving 0.52 g (0.41 mmol) of hexaammonium hexaammonium tetrahydrate in 1.2 ml of distilled water was added dropwise over 10 minutes and kneaded. Then, it was dried overnight at 110 ° C. and calcined at 550 ° C. for 4 hours to obtain a molybdenum-containing MFI-type zeolite.

The obtained molybdenum-containing MFI-type zeolite contains 1.05 wt% of molybdenum, has a 10-membered ring skeleton structure, has an average particle size of 40 nm, a SiO ₂ / Al ₂ O ₃ molar ratio of 68, and has no acid spot on the surface. The acid content was 0.23 mmol / g.

Example 5
An iron-containing MFI-type zeolite was obtained by the same method as in Example 1 except that 0.30 g (0.73 mmol) of iron nitrate nine hydrate was used instead of 0.32 g of potassium nitrate pentahydrate.

The obtained iron-containing MFI-type zeolite contains 0.97 wt% of iron, has a 10-membered ring skeleton structure, has an average particle size of 40 nm, a SiO ₂ / Al ₂ O ₃ molar ratio of 68, and has no acid spot on the surface. The acid content was 0.26 mmol / g.

Example 6
Using the gallium-containing zeolite obtained in Example 1, an aromatization reaction was carried out according to the above using 1-butene as a raw material. The reaction results are shown in Table 1. The decrease in yield after 480 minutes was slight, and it was possible to stably produce an aromatic compound from unsaturated aliphatic hydrocarbons in high yield.

It was confirmed that the reaction efficiency and durability during the aromatization reaction were excellent.

Comparative Example 1
Using the metal-free MFI-type zeolite obtained in Preparation Example 1, an aromatization reaction was carried out using 1-butene as a raw material. The results are shown in Table 3.

Both the conversion rate and the aromatic yield were low.

Preparation Example 2
Crystallization, washing, and drying of zeolite by autoclave were carried out in the same manner as in Preparation Example 1.

The obtained dry powder was calcined under air at 550 ° C., and the obtained powder was dispersed in 1 mol / L hydrochloric acid, filtered and dried to obtain zeolite.

The obtained zeolite had a 10-membered ring skeleton structure, an average particle size of 41 nm, a SiO ₂ / Al ₂ O ₃ molar ratio of 46, and an acid content of 0.22 mmol / g.

The difference spectrum of infrared absorption before and after adsorbing 2,4-dimethylquinoline on the obtained zeolite is shown in FIG. A peak derived from OH zeolite acid sites of 3605cm ^-1, a peak derived from OH of silanol 3700～3800Cm ^-1 decreased. Therefore, it was confirmed that 2,4-dimethylquinoline was adsorbed on the acid spots on the surface of the zeolite and silanol, and that the acid spots were present on the surface of the zeolite.

The present invention provides a novel metal-containing zeolite having no acid spot on the surface, and the metal-containing zeolite has specific stability during, for example, a conversion reaction or an isomerization reaction of an aliphatic hydrocarbon. Its industrial value is extremely high in order to develop efficiency.

It is a figure which shows the infrared absorption spectrum of the zeolite (before and after adsorption of 2,4-dimethylquinoline) obtained in Preparation Example 1 and Preparation Example 2.

Claims (5)

At least one metal selected from the periodic table Group 6-10 and 12-13 group carries, those having the following characteristics (i) ~ (iv), the metal 0.05-5% A metal- supported zeolite characterized by being contained.
(I) The average particle size (PD) is PD ≦ 100 nm.
(Ii) The skeletal structure is a 10-membered ring structure.
(Iii) There are no acid spots on the surface.
(Iv) The amount of acid is 0.05 to 0.85 mmol / g. The metal-supporting zeolite according to claim 1, wherein the metal is at least one metal selected from molybdenum, manganese, iron, cobalt, nickel, palladium, platinum, zinc and gallium. The metal-supported zeolite according to claim 1 or 2, wherein the SiO ₂ / Al ₂ O ₃ ratio is 20 to 300. The metal-supported zeolite according to any one of claims 1 to 3, which is selected from the group consisting of MFI-type zeolite, MEL-type zeolite, and FER-type zeolite. A zeolite having the following characteristics (v) to (viii) is used as a base material, and at least one metal selected from groups 6 to 10 and 12 to 13 of the periodic table is supported, and the metal is 0.05 to 5 wt. A metal- supported zeolite characterized by containing%.
(V) PD ≦ 100 nm.
(Vi) The skeletal structure is a 10-membered ring structure.
(Vii) There are no acid spots on the surface.
The amount of (viii) acid is 0.1 to 1.0 mmol / g .

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