Heating method for zeolite, reaction method, production method for reaction product, and catalyst

Abstract

To provide a method that improves efficiency of microwave heating of zeolite supporting metal cations.SOLUTION: A heating method for zeolite according to an embodiment comprises a step of heating the zeolite by applying microwaves to zeolite supporting metal cations in pores of a crystal structure, wherein a dielectric loss coefficient of the zeolite supporting metal cations is 0.05 or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION Embodiments of the present invention relate to a method for heating a zeolite, a reaction method, a method for producing a reaction product, and a catalyst. [Background technology]

[0002] Zeolites containing metal cations are known to have catalytic activity in various chemical reactions. In order to activate catalytic reactions, zeolite catalysts are sometimes heated with microwaves (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-023938 Summary of the Invention [Problem to be solved by the invention]

[0004] However, there is still room for improvement in the efficiency of microwave heating. For example, although zeolites can have various crystal structures and can support various metal cations, it is not known how to best combine metal cations and zeolite structures to improve microwave heating efficiency.

[0005] The problem to be solved by the present invention is to provide a zeolite heating method, a reaction method, a method for producing a reaction product, and a catalyst that can improve the efficiency of microwave heating of zeolite supporting metal cations. [Means for solving the problem]

[0006] The present inventors focused on the combination of metal cations and zeolite structures to search for combinations with excellent heating properties. As a result, they focused on the dielectric loss coefficient tanδ, which can be used as an indicator of excellent heating properties, and found that microwave heating efficiency can be improved by selecting a combination of metal cations and zeolite structures that increases the value of tanδ.

[0007] The present invention may include the following aspects. [1] A method for heating zeolite, comprising: The method includes a step of heating a zeolite carrying metal cations in pores of a crystalline structure by irradiating the zeolite with microwaves, The method, wherein the zeolite carrying the metal cations has a dielectric loss factor of 0.05 or more. [2] The method according to [1], wherein the ionic radius (6-coordinate) of the metal cation is 0.6 Å or more and 2 Å or less. [3] The method according to [1] or [2], wherein the zeolite has a pore diameter of 1 Å or more and 20 Å or less. [4] The method according to any one of [1] to [3], wherein the pore diameter Rz of the zeolite and the ionic radius (6-coordinate) Rm of the metal cation satisfy the following relational expression 1: [Equation 1] 1≦Rz / Rm≦8.5 [5] The method according to any one of [1] to [4], wherein the zeolite supporting the metal cations has a dielectric loss coefficient of 0.1 or more and 1 or less. [6] The method according to any one of [1] to [5], wherein the metal cation is a monovalent cation. [7] The method according to any one of [1] to [6], wherein the metal cation is a cation of a metal element of the fourth period or later. [8] The method according to any one of [1] to [7], wherein the metal cation comprises one or more selected from the group consisting of indium (I) ions, potassium (I) ions, rubidium (I) ions, and cesium (I) ions. [9] The method according to [8], wherein the metal cation comprises at least one selected from the group consisting of indium (I) ions and cesium (I) ions.

[10] The method according to any one of [1] to [9], wherein the zeolite is one or more zeolites selected from the group consisting of FAU type, FER type, CHA type, BEA type, and MFI type.

[11] A reaction method comprising a step of heating a zeolite in contact with a reactant by the method according to any one of [1] to

[10] , thereby causing a chemical reaction catalyzed by the zeolite.

[12] A method for producing a reaction product, comprising obtaining a product of a chemical reaction that has proceeded by the method described in

[11] .

[13] A catalyst comprising a zeolite that supports metal cations in the pores of its crystalline structure, wherein the zeolite that supports the metal cations has a dielectric loss coefficient of 0.05 or more.

[14] The catalyst according to

[13] , for heating by microwave. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a zeolite heating method, a reaction method, a method for producing a reaction product, and a catalyst that can improve the efficiency of microwave heating of zeolite supporting metal cations. DETAILED DESCRIPTION OF THE INVENTION

[0009] The following describes the zeolite heating method, reaction method, reaction product production method, and catalyst of the embodiment. Note that the following embodiment shows one aspect of the present invention, does not limit the present invention, and can be arbitrarily modified within the scope of the technical concept of the present invention. Furthermore, each configuration and each feature of the embodiment can be arbitrarily combined.

[0010] <1. Zeolite heating method> The method for heating zeolite according to the present embodiment includes a step of heating the zeolite by irradiating microwaves onto the zeolite that supports metal cations in the pores of its crystalline structure. The dielectric loss coefficient (measured at 30°C) of the zeolite that supports the metal cations is 0.05 or more.

[0011] [1-1. Zeolite] Generally, zeolite means crystalline aluminosilicate. Crystalline aluminosilicate is a porous material whose skeletal structure is a network formed by silicon atoms (Si) and aluminum atoms (Al) via oxygen atoms (O). Zeolite has cations in its crystalline structure, and the positive charge of the cations balances the negative charge of the crystalline structure composed of aluminosilicate. The general formula of zeolite is M 2 / n It is expressed as O·Al2O3·xSiO2·yH2O (x≧2), where M is the cation and n is the valence of the cation M.

[0012] As used herein, "zeolite" refers to a compound comprising a zeolite framework and metal cations supported in the pores of the zeolite's crystalline structure. As used herein, "heating a zeolite" refers to an increase in the temperature of the zeolite, and includes not only the direct heating of the zeolite framework but also the heating of the zeolite framework as a result of heating the metal cations supported in the zeolite's crystalline structure.

[0013] The present specification describes the use of zeolites as catalysts, and the term "zeolite functions as a catalyst" includes cases where the zeolite framework itself functions as a catalyst, cases where metal cations supported in the pores of the zeolite crystal structure function as a catalyst, and cases where both of these function as catalysts.

[0014] The zeolite may be a natural zeolite or a synthetic zeolite.

[0015] (1-1-1. Zeolite Structure) The structure of the zeolite is not particularly limited. The structure of the zeolite refers to the framework structure of the structure code defined by the International Zeolite Association (IZA). Examples of structure codes include, but are not limited to, AEI, AFX, BEA, CHA, ERI, FAU, FER, LTA, LTL, MFI, MWW, and MOR. Multiple types of zeolites having different zeolite structures may be mixed. For example, the zeolite may be one or more zeolites selected from the group consisting of FAU-type, FER-type, CHA-type, BEA-type, and MFI-type zeolites.

[0016] The size of the pores formed in the crystal structure (hereinafter referred to as "pore diameter") varies depending on the zeolite structure. Here, in this specification, "pore diameter" means the maximum diameter of a sphere that can be included or the maximum diameter of a sphere that can be diffused along, as listed in the International Zeolite Association's web database "Database of Zeolite Structures" (https: / / www.iza-structure.org / databases / ). When both the maximum diameter of a sphere that can be included and the maximum diameter of a sphere that can be diffused are listed, the value of the maximum diameter of a sphere that can be included is used. When the maximum diameter of a sphere that can be diffused varies depending on the crystal axis direction, the smallest value is used.

[0017] The pore size of the zeolite may be, for example, but not limited to, 1 Å to 20 Å. For example, the pore size of the zeolite may be 1.2 Å to 1 Å, 1.4 Å to 10 Å, 1.6 Å to 9.5 Å, 1.8 Å to 9 Å, 2 Å to 8.5 Å, 2.2 Å to 8 Å, 2.4 Å to 7.5 Å, 2.6 Å to 7 Å, 2.8 Å to 6.5 Å, 3 Å to 6 Å, 3.2 Å to 5.5 Å, 3.4 Å to 5 Å, 3.6 Å to 4.5 Å, or 3.8 Å to 4 Å.

[0018] The molar ratio of silica to alumina in the zeolite (hereinafter referred to as the "SiO2 / Al2O3 ratio") is not particularly limited. The SiO2 / Al2O3 ratio may be, for example, from 2 to 50, but is not limited thereto. For example, the SiO2 / Al2O3 ratio may be from 2 to 40, from 2.5 to 30, from 3 to 25, from 5 to 20, or from 10 to 15.

[0019] (1-1-2. Metal cations) In this embodiment, the cation M supported in the zeolite crystal structure is a metal cation. Examples of metal cations include sodium (I) ions (Na + ), potassium (I) ion (K + ), rubidium(I) ion (Rb + ), cesium(I) ion (Cs + ), indium(I) ion (In + ), silver(I) ions (Ag + ), thallium(I) ion (Tl + ), magnesium ions (Mg 2+ ), calcium ions (Ca 2+ ), scandium ions (Sc 2+ ), barium ions (Ba 2+ ), cobalt(II) ion (Co 2+ ), nickel(II) ions (Ni 2+ ), copper(I) ion (Cu + ), copper(II) ion (Cu 2+ ), zinc(II) ion (Zn 2+ ), palladium(II) ion (Pd 2+ ), gallium(III) ion (Ga 3+ ) and the like, but are not limited to these. It may be a cation of another metal element, or an indium (III) ion (In 3+ ) may have a different valence from the above examples. Also, multiple types of metal cations may be supported in the pores of the zeolite. The cation M may be partially supported by non-metal cations (protons H + , ammonium ion NH4 + etc.)

[0020] Zeolites carrying metal cations such as those described above can be heated by microwave irradiation. The details of microwave irradiation will be described later, but the principle of microwave heating is presumed to be as follows. However, the present invention is not limited to this presumption. (1) Microwaves induce vibrational motion in metal cations, increasing their kinetic energy, which in turn increases the local temperature of the metal cations (this has been experimentally confirmed by the present inventors). (2) The vibrational motion of the metal cations is transmitted to the zeolite framework surrounding the metal cations, inducing lattice vibrations in the zeolite framework. (3) The temperature of the zeolite increases due to lattice vibrations of the zeolite framework.

[0021] Preferably, the metal cation is a monovalent cation for the following reasons. The number of metal cations supported in the zeolite crystal structure is inversely proportional to the valence of the metal cations, so the amount of metal cations supported in the zeolite crystal structure is greatest for monovalent metal cations. According to the microwave heating mechanism described above, it is presumed that the greater the amount of metal cations, the higher the heating efficiency of the zeolite framework. Therefore, monovalent cations are most preferable as metal cations supported by zeolites. Furthermore, cations with a valence of two or more have a larger charge than monovalent cations, and are therefore constrained by electrostatic interactions with the surrounding zeolite crystal structure, making them less likely to vibrate. This is presumed to result in reduced microwave heating efficiency.

[0022] Preferably, the metal cation is a cation of a metal element of period 4 or later, and more preferably, a cation of a metal element of period 5 or later or period 6 or later, for the following reasons. It is presumed that the larger the ionic radius of the metal cations supported in the pores of the zeolite, the smaller the distance between the outer shell of the metal cation and the zeolite framework surrounding the metal cation (i.e., the metal cation fits more easily into the pores of the zeolite), making it easier for the vibrational motion of the metal cations to be transmitted to the surrounding zeolite framework. Furthermore, according to the above-described microwave heating mechanism, it is presumed that the more easily the vibrational motion of the metal cations is transmitted to the surrounding zeolite framework, the higher the heating efficiency of the zeolite framework. Therefore, it is presumed that the larger the ionic radius of the metal cations supported in the pores of the zeolite, the higher the heating efficiency of the zeolite framework. Generally, the ionic radius increases as you move down the periodic table, so it is presumed that the heating efficiency of the zeolite framework increases.

[0023] Preferably, the metal cations include one or more selected from the group consisting of indium(I) ions, sodium(I) ions, potassium(I) ions, rubidium(I) ions, and cesium(I) ions. These metal cations have been demonstrated to exhibit excellent heating properties in the experimental examples described below. More preferably, the metal cations include one or more selected from the group consisting of indium(I) ions and cesium(I) ions. These two types of metal cations have been demonstrated to exhibit particularly excellent heating properties in the experimental examples described below.

[0024] The ionic radius of the metal cation may be, for example, 0.6 Å to 2 Å, 0.7 Å to 1.9 Å, 0.8 Å to 1.8 Å, 0.9 Å to 1.7 Å, 1.0 Å to 1.6 Å, 1.1 Å to 1.5 Å, or 1.2 Å to 1.4 Å. Here, the "ionic radius" in this specification refers to the value for hexacoordination. As described above, it is presumed that, assuming a constant zeolite pore size, the larger the ionic radius, the more likely the heating efficiency will improve. However, if the ionic radius is too large to fit into the zeolite pores, the zeolite will be unable to support the metal cations, and therefore the ionic radius will be smaller than the zeolite pore size.

[0025] (1-1-3. Relationship between zeolite pore size and ionic radius of metal cations) As mentioned above, it is speculated that the closer the metal cation fits into the zeolite pores, the easier it is for the vibration of the metal cation to be transmitted to the zeolite framework, resulting in improved microwave heating efficiency. Therefore, if the ionic radius of the metal cation is Rm and the pore diameter of the zeolite is Rz, the relative value representing their relationship can be considered an index of heating characteristics. Examples of such relative values ​​include Rz / Rm, Rm / Rz, and Rz-Rm.

[0026] Rz / Rm is a relative value that indicates how many times the pore diameter of the zeolite is compared to the ionic radius of the metal cation. For example, Rz / Rm is 1 to 8.5, 2 to 8, 3 to 7.5, 4 to 7, 4.5 to 6.5, or 5 to 6. When Rz / Rm is 1 to 7.5, the vibration of the metal cation is efficiently transmitted to the zeolite framework, and sufficient heating efficiency can be achieved.

[0027] Rm / Rz is a relative value that indicates the ratio of metal cations occupying the pores of the zeolite. For example, Rm / Rz is 0.12 to 1, 0.13 to 0.5, 0.14 to 0.4, or 0.15 to 0.3. When Rm / Rz is 0.12 to 1, the vibration of the metal cations is efficiently transmitted to the zeolite framework, and sufficient heating efficiency can be achieved.

[0028] Rz-Rm is a relative value that indicates the size of the gaps in the zeolite pores when metal cations are accommodated. For example, Rz-Rm is 1 Å to 7.9 Å, 2 Å to 7.8 Å, 3 Å to 7.7 Å, or 4 Å to 7.5 Å. If Rz-Rm is 1 Å to 7.9 Å, the vibrations of the metal cations are transmitted well to the zeolite framework, and sufficient heating efficiency can be achieved.

[0029] When multiple types of metal cations and / or zeolite structures are present, it is sufficient that the ionic radius Rm of at least one metal cation and the pore diameter Rz of at least one zeolite satisfy the above relationship.

[0030] Even if the above relative value is within the preferred range, sufficient heating efficiency may not be obtained if the valence of the metal cation is 2 or more. Therefore, it is most preferable that the above range is satisfied when the valence of the metal cation is 1 or more.

[0031] (1-1-4. Dielectric loss coefficient (dielectric tangent) of zeolite) As explained above, the relationship between the ionic radius of metal cations and the pore size of zeolite can be used as an indicator of heating efficiency. However, the ionic radius varies depending on the coordination number and valence. Furthermore, there are ions for which no literature values ​​exist. Therefore, the inventors further investigated indicators of heating efficiency that do not use ionic radius and found that the dielectric loss factor (dielectric tangent) tanδ is useful as an indicator of heating efficiency.

[0032] The dielectric loss coefficient here is measured using a 915MHz semiconductor microwave oscillator (manufactured by Ryowa Electronics, model name: MR-0.9G-300) and a TM 010 The measurements were carried out using a circular cavity resonator (manufactured by Ryowa Electronics, inner diameter 260 mm, height 20 mm) of the 1000-mV mode. Specific measurement conditions are described below. The dielectric loss coefficient measurements in the examples described below were carried out under these measurement conditions. (1) 50 mg to 150 mg of metal cation-supported zeolite is filled into a quartz container and introduced into a cavity resonator. (2) Irradiate electromagnetic waves with a microwave output of 10 W or more and measure the resonant frequency and Q value. (3) Using these values, calculate the dielectric constant (ε'), dielectric loss factor (ε"), and dielectric loss coefficient (tan δ) according to the following equations: (4) The zeolite sample is placed at room temperature (e.g., 30°C). (5) The zeolite sample is placed under a nitrogen gas flow at normal pressure, and the nitrogen gas is supplied at a flow rate of 50 mL / min.

[0033] The dielectric constant (ε'), dielectric loss factor (ε"), and dielectric loss coefficient (tanδ) are calculated from the resonance frequency and Q value measured in (2) above using the following formulas. Here, the subscripts "L" and "0" represent the values ​​before and after sample insertion, respectively.

number

number

number

number

[0034] where Q, f, and Δf are the 21 The parameters Q value, the frequency at the top of the resonance peak (i.e., the resonance frequency), and the full width at half maximum of the resonance peak are shown. n is a constant determined depending on the resonance mode, and TM 010 In mode, it is 1.85515. V is TM 010 represents the internal volume of the circular cavity of the mode, and ΔV represents the volume of the sample.

[0035] The dielectric loss factor is a physical constant that varies depending on the type of metal cation and the type of zeolite structure. Generally, when an external AC electric field is applied to a dielectric, a portion of the electrical energy supplied by the electric field is consumed as heat energy by the dielectric, which is called dielectric loss. Ideally, there is a phase difference of π / 2 between the phase of the external AC electric field and the phase of the current caused by the polarization and electrification reversal of the dielectric, but in reality, this phase difference deviates from π / 2 due to the influence of dielectric loss and other factors. This deviation is called the dielectric loss angle δ, and its tangent (tanδ) is called the dielectric loss coefficient or dielectric dissipation factor.

[0036] The dielectric loss factor is proportional to the dielectric loss and therefore serves as an indicator of the heat energy generated when zeolite, a dielectric material, is irradiated with microwaves, an external alternating electromagnetic field. In other words, the larger the dielectric loss factor, the easier it is to heat a material with microwaves. According to the above-mentioned speculated mechanism, metal cations irradiated with microwaves convert the electrical energy of the microwaves into kinetic energy, such as vibrations. This kinetic energy is then converted into lattice vibrations in the zeolite framework, thereby increasing the temperature (i.e., generating heat). Therefore, the easier it is for kinetic energy, such as vibrations, to be transmitted from the metal cations to the zeolite framework, the easier it is for microwave heating to occur, and the larger the dielectric loss factor. Therefore, the dielectric loss factor can be used to represent the ease of energy transmission from metal cations to the zeolite framework, instead of the ionic radius, which is difficult to determine experimentally and whose literature values ​​are not always consistent.

[0037] In fact, as will be shown in the experimental examples described later, it has been confirmed that excellent heating efficiency can be achieved by microwave irradiation if the dielectric loss coefficient tan δ is 0.05 or more. Preferably, the dielectric loss coefficient tan δ may be 0.05 to 1, 0.06 to 0.9, 0.07 to 0.8, 0.08 to 0.75, 0.09 to 0.7, 0.1 to 0.65, 0.11 to 0.6, 0.12 to 0.58, 0.13 to 0.56, 0.14 to 0.54, 0.15 to 0.52, 0.16 to 0.5, 0.17 to 0.49, 0.18 to 0.48, 0.19 to 0.47, 0.2 to 0.46, 0.21 to 0.45, 0.22 to 0.44, or 0.23 to 0.43.

[0038] Even if the dielectric loss factor is within the preferred range, sufficient heating efficiency may not be obtained if the valence of the metal cation is 2 or more. Therefore, it is most preferable that the dielectric loss factor satisfies the above range when the valence of the metal cation is 1 or more.

[0039] (1-1-5. Zeolite manufacturing method The zeolite may be commercially available or may be produced by a known method. Generally, commercially available zeolites contain protons (H + ), ammonium ion (NH4 + ), or sodium ions (Na + ) is supported on the zeolite. For example, zeolites supporting desired metal cations can be obtained by ion-exchanging commercially available zeolites. The specific method of ion-exchange is not particularly limited, and any known method can be used as long as it can support the desired metal cations on the zeolite. Examples of the method include, but are not limited to, the following methods. (a) A method in which the raw material zeolite is dispersed in an aqueous solution containing the desired metal cations and stirred. (b) A method in which an aqueous solution containing the desired metal cations is passed through a column packed with the raw zeolite. (c) A method of mixing the raw material zeolite powder with a powder containing the desired metal cation (for example, a metal oxide powder) and firing the mixture (if necessary, firing may be carried out in a reducing atmosphere).

[0040] [1-2. Microwave heating] Zeolite can be heated by irradiating it with microwaves. Any known microwave generator can be used. For example, a semiconductor diode, a magnetron, a klystron, a traveling wave tube (TWT), etc.

[0041] The microwave frequency is not particularly limited as long as it is within the range of about 300 MHz to about 300 GHz, which is the general microwave frequency range. Since the optimal frequency can vary depending on conditions such as the type of metal cation and the zeolite structure, the microwave frequency may be appropriately selected depending on various conditions such as the type of zeolite, reaction conditions, and reaction target. For example, the microwave frequency may be, but is not particularly limited to, 300 MHz to 300 GHz, 500 MHz to 100 GHz, 700 MHz to 10 GHz, or 900 MHz to 1 GHz.

[0042] In general, it is believed that the higher the microwave output, the faster the zeolite is heated. For example, the microwave output may be, but is not limited to, 10 W to 1000 W, 20 W to 500 W, 50 W to 300 W, 80 W to 200 W, or 100 W to 150 W.

[0043] <2. Reaction method> The reaction method according to this embodiment includes a step of heating the zeolite in contact with the reactants by the heating method described above, thereby causing a chemical reaction catalyzed by the zeolite.

[0044] Various chemical reactions are known to use zeolites as catalysts. The above method can be applied to any reaction. Examples of reactions in which zeolites function as catalysts include oxidation or reduction reactions of hydrocarbons, hydroconversion reactions of carbon dioxide, cracking (catalytic cracking) of hydrocarbons, reforming, and dehydration condensation of alcohols.

[0045] The method may further include contacting the zeolite with a reactant. The reactant may be a raw material for a chemical reaction catalyzed by the zeolite. The chemical reaction may be a solid-phase reaction, a liquid-phase reaction, or a gas-phase reaction. By irradiating microwaves onto the zeolite while it is in contact with the reactant, the zeolite can be heated to promote or accelerate the catalytic reaction. Such microwave heating can locally and selectively heat the zeolite, making it easier to control the progress of the catalytic reaction compared to uniformly heating the entire reaction system using a heater such as a hot plate or oil bath.

[0046] <3. Method for producing reaction product> The method for producing a reaction product according to this embodiment includes a step of obtaining a product of a chemical reaction that has proceeded by the above-described reaction method.

[0047] As described above, the chemical reaction to which the method is applied is not particularly limited. Accordingly, the product is also not particularly limited and may be any product obtained by any catalytic reaction that can be advanced or accelerated by heating the zeolite as a catalyst. The product may also include intermediate products.

[0048] 4. Catalyst The catalyst according to this embodiment contains zeolite that supports metal cations in the pores of its crystal structure, and the dielectric loss coefficient of the zeolite that supports the metal cations is 0.05 or more.

[0049] Preferably, the catalyst is a catalyst for heating with microwaves. More preferably, the catalyst is a catalyst for promoting or accelerating a catalytic reaction by heating zeolite with microwaves. The catalyst may further contain a substance other than zeolite.

[0050] <5. Effects> The above-described zeolite heating method can improve the efficiency of microwave heating. By using the dielectric loss coefficient as an indicator of heating efficiency, it is possible to discover combinations of metal cations and zeolite structures that are easily heated by microwaves. This makes it possible to achieve high heating efficiency without the need for additives such as heating aids. Furthermore, microwave irradiation can heat the zeolite locally and selectively, rather than the entire reaction system. This allows chemical reactions catalyzed by the zeolite to proceed locally and selectively. This makes it possible to suppress side reactions. [Example]

[0051] The present invention will be described below with reference to experimental examples, but the present invention is not limited to the following experimental examples.

[0052] <Experimental Example 1> NH4 in the pores of the crystal structure + Cation-supported MFI-type zeolite (HSZ-820NHA; Si / Al = 11.5; average particle size ~ 250 nm; specific surface area ~ 340 m 2 / g; manufactured by Tosoh Corporation) was used as a raw material and ion exchange was carried out by the liquid phase ion exchange method as follows. First, indium nitrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was dissolved in pure water to prepare a 0.05M indium nitrate aqueous solution. Next, 1 g of MFI zeolite was dispersed in 100 mL of this indium nitrate aqueous solution and stirred at 80°C for 6 hours. Next, the dispersed zeolite was recovered by centrifugation and redispersed in a fresh indium nitrate aqueous solution. After repeating this procedure three times, the zeolite was washed with water and dried overnight at 50°C. In this way, In was dispersed in the pores of the crystalline structure. + A powder sample of MFI-type zeolite carrying α-methyl-2-pyrrolidone was obtained.

[0053] <Experimental Examples 2-5> In Experimental Examples 2 to 5, powder samples of MFI-type zeolite carrying metal cations in the pores of the crystalline structure were obtained in the same manner as in Experimental Example 1, except that cesium nitrate, rubidium nitrate, potassium nitrate, and sodium nitrate (all manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were used instead of indium nitrate.

[0054] <Experimental Example 6> In Experimental Example 6, the NH4 + By treating the cation-supported MFI zeolite at 550°C overnight in air, H was introduced into the pores of the crystal structure. + A powder sample of MFI-type zeolite carrying α-methyl-2-pyrrolidone was obtained.

[0055] <Experimental Examples 7-10> In Experiments 7 to 10, NH4 + Instead of MFI type zeolite supporting cations, NH4 + In was introduced into the pores of the crystal structure in the same manner as in Experimental Example 1, except that cation-supporting FER-type zeolite (product name HSZ-720NHA; Si / Al=9; manufactured by Tosoh Corporation), CHA-type zeolite (synthesized by a known method), BEA-type zeolite (product name HSZ-930NHA; Si / Al=13.5; manufactured by Tosoh Corporation), and FAU-type zeolite (HSZ-371NHA; Si / Al=12.5; manufactured by Tosoh Corporation) were used. + Powder samples of FER, CHA, BEA, and FAU zeolites carrying Zn were obtained.

[0056] <Experimental Examples 11-14> In Experimental Examples 11 to 14, powder samples of FAU-type zeolite carrying alkali metal cations in the pores of the crystalline structure were obtained in the same manner as in Experimental Example 10, except that cesium nitrate, rubidium nitrate, potassium nitrate, and sodium nitrate (all manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were used instead of indium nitrate.

[0057] <Experimental Examples 15-19> In Experimental Examples 15 to 19, powder samples of MFI-type zeolite carrying metal cations in the pores of the crystalline structure were obtained in the same manner as in Experimental Example 1, except that cobalt nitrate, nickel nitrate, zinc nitrate, gallium nitrate, and palladium nitrate (all manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were used instead of indium nitrate.

[0058] <Evaluation Example 1: Dielectric and Heating Properties of Sample> The dielectric properties and heating properties of each of the obtained samples were evaluated as follows. A GaN semiconductor microwave generator (manufactured by Ryowa Electronics Co., Ltd.) was connected to a cylindrical cavity resonator (TM 010 In addition, a signal sensor for measuring S parameters was attached to the semiconductor microwave generator. The cavity was filled with the sample and irradiated with microwaves at a frequency of 915 MHz. Nitrogen gas was used as the feed gas, and the flow rate of the feed gas was 50 mL / min. The surface temperature of the sample was monitored using an infrared radiation thermometer (FLHX series; manufactured by Nippon Sensor Co., Ltd.). For Experimental Examples 1 to 5 and Experimental Examples 7 to 14, the surface temperature was raised to 500 °C by microwave irradiation, and the microwave power required to maintain the surface temperature at 500 °C (hereinafter referred to as "500 °C maintenance power") was then measured. For Experimental Examples 6 and 15 to 19, the surface temperature could not be raised to 500 °C with a microwave power of up to 250 W, so the maximum surface temperature (hereinafter referred to as "achieved temperature") when irradiated with microwaves at a power of 250 W was recorded. Note that for Experimental Examples 12 to 14, the surface temperature was not stable, so the "500 °C maintenance power" value could not be accurately measured.

[0059] The measurement results of the dielectric loss coefficient for the samples obtained in each experimental example are summarized in Table 1 below. [Table 1]

[0060] In Experiments 2 to 5, in which the same MFI-type zeolite was used but the type of alkali metal ion was changed, it was confirmed that all zeolites had a tendency to have a larger dielectric loss coefficient tanδ and a smaller 500°C maintenance output compared to Experiment 6, which used a zeolite containing protons. Here, the smaller the 500°C maintenance output, the easier the sample is to heat, so it can be said that the heating characteristics are excellent. On the other hand, when the metal cation is In + When comparing Experimental Example 1 and Experimental Examples 7 to 10, in which the structure of the zeolite was changed as a catalyst, it was confirmed that the smaller the pore diameter of the zeolite, the smaller the 500°C maintenance output, and the tendency for the heating characteristics to be excellent. + When Experimental Example 1, in which a divalent or trivalent metal cation was used, was compared with Experimental Examples 15 to 19, in which a divalent or higher metal cation was used, it was found that the monovalent metal cation In + It was confirmed that the dielectric loss coefficient tan δ tended to be smaller than when using the SiO2 film, and neither of them reached 500°C at outputs up to 250W.

[0061] <Evaluation Example 2: Catalytic Properties> Cs produced in Experimental Example 11 + A test oxidation reaction of methane gas was carried out using FAU-type zeolite carrying cations as a catalyst. The catalytic reaction proceeded when microwaves were irradiated at a power of 40 W. The temperature of the zeolite catalyst bed was monitored with an IR thermometer and maintained at approximately 500°C. A test oxidation reaction of carbon monoxide was also carried out, and the catalytic reaction proceeded under similar conditions. To achieve the same level of heating using a conventional heating furnace, a power of 164 W was required, which is about four times the power of the microwave heating mentioned above.

Claims

1. A method for heating zeolite, comprising the steps of: The method includes a step of heating a zeolite carrying metal cations in pores of a crystalline structure by irradiating the zeolite with microwaves, The method, wherein the zeolite carrying the metal cations has a dielectric loss factor of 0.05 or more.

2. The method of claim 1, wherein the ionic radius (6-coordinate) of the metal cation is 0.6 Å or more and 2 Å or less.

3. The method according to claim 1 or 2, wherein the pore diameter of the zeolite is 1 Å or more and 20 Å or less.

4. 3. The method according to claim 1, wherein the pore diameter Rz of the zeolite and the ionic radius (six-coordination) Rm of the metal cation satisfy the following relationship 1: [Relationship 1] 1≦Rz / Rm≦8.5

5. 3. The method according to claim 1, wherein the zeolite carrying the metal cations has a dielectric loss coefficient of 0.1 or more and 1 or less.

6. 3. The method of claim 1, wherein the metal cation is a monovalent cation.

7. The method according to claim 1 or 2, wherein the metal cation is a cation of a metal element of the fourth period or later.

8. 3. The method of claim 1, wherein the metal cation comprises one or more selected from the group consisting of indium (I) ions, sodium (I) ions, potassium (I) ions, rubidium (I) ions, and cesium (I) ions.

9. 9. The method of claim 8, wherein the metal cations comprise one or more selected from the group consisting of indium (I) ions and cesium (I) ions.

10. 3. The method according to claim 1, wherein the zeolite is one or more zeolites selected from the group consisting of FAU type, FER type, CHA type, BEA type, and MFI type zeolite.

11. A reaction method comprising the step of heating a zeolite in contact with a reactant by the method of claim 1 or 2, thereby causing a chemical reaction catalyzed by the zeolite.

12. 12. A method for producing a reaction product, comprising obtaining a product of a chemical reaction proceeded by the method of claim 11.

13. A catalyst comprising a zeolite that supports metal cations in the pores of its crystalline structure, wherein the zeolite that supports the metal cations has a dielectric loss coefficient of 0.05 or more.

14. Catalyst according to claim 13 for heating by microwaves.

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