JP2023079580A - Oxide catalyst and method for producing hydrocarbon - Google Patents

Abstract

To provide an oxide catalyst that enables an oxidative coupling reaction of methane to proceed at lower temperatures.SOLUTION: An oxide catalyst comprises, as its constitutional elements, at least lanthanum, wherein the oxide catalyst comprises a predetermined combination of first element, second element and third element, or comprises a predetermined combination of first element and second element while being free of a predetermined third element.SELECTED DRAWING: None

Description

The present invention relates to an oxide catalyst and a method for producing hydrocarbons.

BACKGROUND ART Hydrocarbons having 2 carbon atoms (eg, ethane and ethylene) are industrially important compounds in that they serve as raw materials for various compounds.
Hydrocarbons having 2 carbon atoms are generally produced by cracking naphtha. On the other hand, from the viewpoint of effective utilization of resources, the production of hydrocarbons having 2 carbon atoms by the oxidative coupling of methane (OCM) reaction is being studied.

As a catalyst for smoothly advancing the OCM reaction, for example, a catalyst containing sodium and manganese and containing silicon oxide and tungsten oxide (Ma/Na ₂ WO ₄ /SiO ₂ catalyst) is known (non Patent document 1). However, the Ma/Na ₂ WO ₄ /SiO ₂ catalyst required a high temperature of about 800° C. for the reaction. A reaction temperature as high as 800° C. is not preferable because the materials for the reaction vessel and the like are limited.
On the other hand, La ₂ O ₃ is _known to be effective as a catalyst for advancing the OCM reaction at low temperatures _. We are trying to lower the temperature.

Journal of Catalysis, 1998, 222-230 Catalysis Science & Technology, 2021, 11, 524-530

From the point of view of industrialization, it is desired to further lower the reaction temperature of the OCM reaction in order to design and control the reactor and to suppress the decomposition of hydrocarbons having 2 carbon atoms.
When the present inventors investigated how to further lower the reaction temperature of the OCM reaction, they found that the catalysts described in Non-Patent Documents 1 and 2 have room for improvement.

Accordingly, an object of the present invention is to provide an oxide catalyst that allows the oxidative coupling (OCM) reaction of methane to proceed at a lower temperature.
Another object of the present invention is to provide a method for producing hydrocarbons using an oxide catalyst.

The present inventor has completed the present invention as a result of intensive studies in order to solve the above problems. That is, the inventors have found that the above problems can be solved by the following configuration.

[1] An oxide catalyst,
containing at least lanthanum as a contained element,
An oxide catalyst that meets any of the following requirements:
Requirement 1: The oxide catalyst contains gallium or yttrium as the first element, contains one element selected from group 2 elements as the second element, and contains calcium, nickel, gallium, yttrium, as the third element, It contains barium, neodymium, europium, ytterbium, or hafnium, or does not contain the third element. However, the first element, the second element, and the third element are different elements.
Requirement 2: The oxide catalyst contains gallium or yttrium as the first element, contains one element selected from lanthanoid elements other than lanthanum as the second element, and contains silicon, gallium, yttrium, and cerium as the third element. , europium, terbium, ytterbium, hafnium, or tungsten. However, the first element, the second element, and the third element are different elements.
Requirement 3: The oxide catalyst contains gallium or yttrium as the first element, and two elements selected from Group 4 elements as the second and third elements.
Requirement 4: The oxide catalyst contains gallium or yttrium as the first element, zinc as the second element, and gallium, yttrium, zirconium, palladium, europium, or hafnium as the third element. However, the first element, the second element, and the third element are different elements.
Requirement 5: The oxide catalyst contains one element selected from lanthanoid elements other than lanthanum as a first element, one element selected from Group 2 elements as a second element, and a third Contains magnesium, strontium, or hafnium as elements. However, the first element, the second element, and the third element are different elements.
[2] The oxide catalyst according to [1], wherein the requirements 1 to 5 are the following requirements 1A to 5A, respectively.
Requirement 1A: The oxide catalyst contains gallium or yttrium as the first element, calcium, strontium, or barium as the second element, and calcium, nickel, gallium, yttrium, barium, neodymium, and europium as the third element. , ytterbium, or hafnium, or does not contain the third element. However, the first element, the second element, and the third element are different elements.
Requirement 2A: The oxide catalyst contains gallium or yttrium as the first element, cerium, europium, terbium, or ytterbium as the second element, and silicon, gallium, yttrium, cerium, europium, and terbium as the third element. , ytterbium, hafnium, or tungsten. However, the first element, the second element, and the third element are different elements.
Requirement 3A: The oxide catalyst contains gallium or yttrium as the first element, zirconium as the second element, and hafnium as the third element.
Requirement 4A: The oxide catalyst contains gallium or yttrium as the first element, zinc as the second element, and gallium, yttrium, zirconium, palladium, europium, or hafnium as the third element. However, the first element, the second element, and the third element are different elements.
Requirement 5A: The oxide catalyst contains neodymium, europium, or ytterbium as the first element, magnesium, calcium, or strontium as the second element, and magnesium, strontium, or hafnium as the third element. . However, the first element, the second element, and the third element are different elements.
[3] whether the oxide catalyst contains yttrium, europium and hafnium, yttrium, calcium and hafnium, yttrium, calcium and europium, yttrium, calcium and barium, or neodymium and magnesium and hafnium, europium, calcium, and hafnium, yttrium, calcium, and neodymium, neodymium, strontium, and hafnium, europium, magnesium, and hafnium, or gallium and europium and zinc, or magnesium, strontium, and ytterbium, or gallium, strontium, and ytterbium, or gallium, ytterbium, and tungsten, or gallium, calcium, and ytterbium, or , gallium and ytterbium and silicon, or
The oxide catalyst according to [1] or [2], wherein the oxide catalyst contains yttrium and calcium and does not contain any of nickel, gallium, yttrium, barium, neodymium, europium, ytterbium, and hafnium.
[4] The oxide catalyst contains yttrium, europium, and hafnium, yttrium, calcium, and hafnium, yttrium, calcium, and europium, yttrium, calcium, and barium, or europium. and calcium and hafnium, yttrium, calcium and neodymium, europium, magnesium and hafnium, magnesium, strontium and ytterbium, gallium, strontium and ytterbium, gallium and europium and zinc, or gallium, ytterbium, and tungsten, or gallium, calcium, and ytterbium, or gallium, ytterbium, and silicon, or
Any one of [1] to [3], wherein the oxide catalyst contains yttrium and calcium and does not contain any of nickel, gallium, yttrium, barium, neodymium, europium, ytterbium, and hafnium. oxide catalyst.
[5] A hydrocarbon comprising a step of oxidatively coupling methane using the oxide catalyst according to any one of [1] to [4] to produce a hydrocarbon having 2 carbon atoms. manufacturing method.
[6] The method for producing hydrocarbons according to [5], wherein the temperature in the above step is 700°C or lower.

According to the present invention, it is possible to provide an oxide catalyst that allows the OCM reaction to proceed at a lower temperature.
The present invention can also provide a method for producing hydrocarbons.

The present invention will be described in detail below.
The description of the constituent elements described below may be made based on representative embodiments of the present invention, but the present invention is not limited to such embodiments.

Hereinafter, the meaning of each description in this specification is expressed.
In the present specification, a numerical range represented by "to" means a range including the numerical values before and after "to" as lower and upper limits.

<Oxide catalyst>
The oxide catalyst of the present invention contains at least lanthanum (La) as a contained element, and satisfies any of the requirements described later. That is, it contains the elements of the combination described in the requirements described later.
The reason why the oxide catalyst of the present invention allows the OCM reaction to proceed at a lower temperature is not necessarily clear, but the present inventors speculate as follows.
The OCM reaction is exothermic. In the oxide catalyst of the present invention, by containing La and a combination of elements described later, La and the above element, or the above elements act in concert, and a single La ₂ O ₃ catalyst does not react. It is thought that the initial reaction proceeds smoothly at a lower temperature where it is difficult to initiate, and the heat of reaction causes the continuous reaction to proceed. As a result, it is speculated that the oxide catalysts of the present invention allow the OCM reaction to initiate and proceed at lower temperatures.
Hereinafter, when the OCM reaction is allowed to proceed under the same conditions as the single La ₂ O ₃ catalyst using the oxide catalyst of the present invention, it can be progressed at a lower temperature than the single La ₂ O ₃ catalyst. It is also said to be superior to
Hereinafter, requirements that the oxide catalyst of the present invention satisfies will be described, and preferred embodiments for each requirement will be described.

[Requirement 1]
A first aspect of the oxide catalyst of the present invention contains at least lanthanum (La) as a contained element, and satisfies the following requirement 1.
Requirement 1: The oxide catalyst contains gallium (Ga) or yttrium (Y) as the first element, contains one element selected from Group 2 elements as the second element, and contains calcium (Ca ), nickel (Ni), gallium (Ga), yttrium (Y), barium (Ba), neodymium (Nd), europium (Eu), ytterbium (Yb), or hafnium (Hf); Does not contain 3 elements. However, the first element, the second element and the third element are different elements.
That is, the first aspect of the oxide catalyst contains La and the first element, the second element and the third element, or contains La, the first element and the second element and the third element Not included. In addition, the first aspect of the oxide catalyst contains oxygen (O).

Requirement 1 satisfied by the first aspect of the oxide catalyst is preferably Requirement 1A below.
Requirement 1A: The oxide catalyst contains Ga or Y as the first element, calcium (Ca), strontium (Sr), or barium (Ba) as the second element, and Ca, Ni, Ga as the third element. , Y, Ba, Nd, Eu, Yb, or Hf, or no third element. However, the first element, the second element and the third element are different elements.

Combinations of the first element, the second element, and the third element include, for example, a combination of Y, Ca, and Hf, a combination of Y, Mg, and Hf, a combination of Y, Ca, and Eu, and Y and Sr. and Eu, a combination of Y, Ca, and Ba, a combination of Y, Mg, and Ba, a combination of Y, Ca, and Nd, a combination of Y, Sr, and Nd, a combination of Y, Mg, and Ni , a combination of Y, Ca and Ni, a combination of Y, Sr and Ni, a combination of Ga, Ca and Eu, a combination of Ga, Sr and Eu, a combination of Y, Sr and Ga, Y and Ca and a combination of Ga, a combination of Ga, Ca, and Hf; a combination of Ga, Sr, and Hf; a combination of Ga, Sr, and Yb; a combination of Ga, Ca, and Yb; A combination is mentioned.
In terms of excellent low temperature activity, the combination of Y, Ca and Hf, the combination of Y, Ca and Eu, the combination of Y, Ca and Ba, the combination of Y, Ca and Nd, the combination of Y, Ca and Ni a combination of Ga, Sr and Eu, a combination of Y, Sr and Ga, a combination of Ga, Sr and Hf, a combination of Ga, Sr and Yb, a combination of Ga, Ca and Yb, or Ga A combination of Ba and Yb is preferred.
The combination of Y, Ca, and Hf, the combination of Y, Ca, and Eu, the combination of Y, Ca, and Ba, the combination of Y, Ca, and Nd, and the combination of Ga, Sr, and Yb are advantageous in terms of low-temperature activity. A combination or a combination of Ga, Ca and Yb is more preferable, a combination of Y, Ca and Hf, a combination of Y, Ca and Eu, a combination of Y, Ca and Ba, or Y, Ca and Nd A combination with is more preferable.
Examples of the combination of the first element and the second element include a combination of Y and Ca, a combination of Y and Sr, and a combination of Y and Ba. In terms of low temperature activity, the combination of Y and Ca is preferred.

The properties of the first aspect of the oxide catalyst of the present invention are not particularly limited as long as it satisfies Requirement 1 above. The above properties include all states of the oxide catalyst, such as the ratio of constituent elements of the oxide catalyst, the crystal state of the oxide catalyst, the arrangement of each element contained in the oxide catalyst, the shape and size of the oxide catalyst. etc.
The properties of the oxide catalyst are described below.

(Constituent element ratio of oxide catalyst)
The ratio of constituent elements in the first aspect of the oxide catalyst of the present invention is not particularly limited.
The first aspect of the oxide catalyst contains La, the first element, the second element, the third element, and O as constituent elements, or La, the first element, the second element, and O as constituent elements. contain and do not contain a tertiary element.

When the third element is included, the content of each element with respect to the total content of the first element, the second element, and the third element is preferably 5 to 90% by mass, and 10 to 80% as a single element. % by mass is more preferred, and 25 to 50% by mass is even more preferred.
Further, when the third element is included, the total content of the first element, the second element, and the third element is 0.01 to 0.01 with respect to the total mass of the oxide catalyst as the total content of each element alone. 50% by mass is preferable, 0.1 to 10% by mass is more preferable, 0.3 to 5% by mass is more preferable, 0.6 to 3% by mass is particularly preferable, and 0.9 to 1.5% by mass is most preferable. preferable.
When the third element is included, the total content of the first element, the second element, and the third element is 0.01 to 0.01 with respect to the total mass of the oxide catalyst as the total content of the oxides of each element. 65% by mass is preferable, 0.1 to 15% by mass is more preferable, 0.3 to 6.5% by mass is more preferable, 0.6 to 4% by mass is particularly preferable, and 0.9 to 2% by mass is most preferable. preferable.

When the third element is not included, the content of each element with respect to the total content of the first element and the second element is preferably 5 to 95% by mass, more preferably 10 to 90% by mass, as a single element. , 30 to 70 mass % is more preferable.
In addition, when the third element is not included, the total content of the first element and the second element is preferably 0.01 to 50% by mass based on the total mass of the oxide catalyst as the total content of each element alone. , more preferably 0.1 to 10% by mass, more preferably 0.3 to 5% by mass, particularly preferably 0.6 to 3% by mass, and most preferably 0.6 to 1.5% by mass.
When the third element is not included, the total content of the first element and the second element is preferably 0.01 to 65% by mass based on the total mass of the oxide catalyst as the total content of oxides of each element. , more preferably 0.1 to 15% by mass, more preferably 0.3 to 6.5% by mass, particularly preferably 0.6 to 4% by mass, and most preferably 0.6 to 2% by mass.

The content of O is preferably 1 to 30% by mass, more preferably 5 to 25% by mass, even more preferably 10 to 20% by mass, relative to the total mass of the oxide catalyst.
The content of La is preferably 60 to 95% by mass, more preferably 70 to 90% by mass, and even more preferably 80 to 90% by mass, based on the total mass of the oxide catalyst as the content of La alone.

The first aspect of the oxide catalyst may contain elements other than the above constituent elements.
Examples of elements other than the above include carbon (C), nitrogen (N), fluorine (F), phosphorus (P), sulfur (S), chlorine (Cl), and bromine (Br). , but not limited to these.
In the first aspect of the oxide catalyst, La, the first element, the second element, the third element, and O (when the third element is not included, La, the first element, the second element, and O ) is preferably 70% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and particularly preferably 99% by mass or more, relative to the total mass of the oxide catalyst. As for the upper limit of total content, 100 mass % is mentioned.

(Crystal state of oxide catalyst)
The crystal state in the first aspect of the oxide catalyst of the present invention is not particularly limited.
The crystalline state of the oxide catalyst may be amorphous (non-crystalline) or crystalline. The crystallite diameter in the case of crystalline is not particularly limited, and is, for example, 0.5 to 1000 nm.

(Arrangement of Elements in Oxide Catalyst)
Arrangement of elements in the first aspect of the oxide catalyst of the present invention is not particularly limited.
The oxide catalyst may be a composite oxide in which the constituent elements are uniformly mixed, or the oxide of each element may be unevenly distributed in a part of the oxide catalyst.
Among them, when the third element is contained, it is preferable that at least one of the first element, the second element and the third element is present on the surface of the oxide catalyst, and at least two elements are present. It is more preferable that there are 3 types.
When the tertiary element is not contained, at least one of the first element and the second element is preferably present on the surface of the oxide catalyst, and more preferably two of them are present.
At least one of the first element, the second element and the third element (at least one of the first element and the second element when the third element is not included) is present on the surface of the oxide catalyst. When present, the above elements may be unevenly distributed on the surface of the oxide catalyst, or may be uniformly distributed on the surface of the oxide catalyst. Among others, it is preferable that the above elements are uniformly distributed on the surface of the oxide catalyst.

In addition, the oxide of each element of the constituent elements is present in a part (for example, the surface) of the oxide catalyst, and the total content of the constituent elements is the total mass of the oxide catalyst. A preferred range is also preferred.
As an example of the above aspect, La ₂ O ₃ is used as a carrier, and oxides of the first element, the second element and the third element (the first element and the second element when the third element is not included) are supported. Aspects can be mentioned. The oxide of each of the above elements is a composite oxide containing two or more elements selected from the first element, the second element and the third element (the first element and the second element if the third element is not included) may be Further, the composite oxide may contain La.

(Shape of oxide catalyst)
The shape of the oxide catalyst in the first aspect of the oxide catalyst of the present invention is not particularly limited.
The oxide catalyst is usually particulate, and the shape of the particles is not particularly limited.
Examples of the shape of the oxide catalyst include spherical, polyhedral (eg, octahedral, rhomboidal dodecahedral), polygonal prismatic, and tabular shapes. Moreover, it may be an agglomerate formed by aggregating particles having the above shape. Moreover, the shape of the oxide catalyst may be a structure having communication holes through which gas can pass, and may be, for example, a honeycomb shape or a sponge shape.

(Size of oxide catalyst)
The size of the oxide catalyst in the first aspect of the oxide particle catalyst of the present invention is not particularly limited.
The size of the oxide catalyst can be, for example, 0.5 nm to 500 μm.
The size of the oxide catalyst can be measured by a known method according to its size.
In the case of the embodiment in which the simple substance or oxide of the first element, the second element and the third element (the first element and the second element when the third element is not included) is supported, the size of the supported particles The thickness is not particularly limited, but may be, for example, 0.2 to 1000 nm.

[Requirement 2]
The second aspect of the oxide catalyst of the present invention contains at least lanthanum (La) as a contained element, and satisfies the following requirement 2.
Requirement 2: The oxide catalyst contains gallium (Ga) or yttrium (Y) as the first element, contains one element selected from lanthanide elements excluding lanthanum (La) as the second element, and contains a third element as Silicon (Si), Gallium (Ga), Yttrium (Y), Cerium (Ce), Europium (Eu), Terbium (Tb), Ytterbium (Yb), Hafnium (Hf), or Tungsten (W). However, the first element, the second element and the third element are different elements.

Requirement 2, which the second aspect of the oxide catalyst satisfies, is preferably Requirement 2A below.
Requirement 2A: The oxide catalyst contains Ga or Y as the first element and Cerium (Ce), Neodymium (Nd), Europium (Eu), Terbium (Tb), or Ytterbium (Yb) as the second element. , Si, Ga, Y, Ce, Eu, Tb, Yb, Hf, or W as a third element. However, the first element, the second element and the third element are different elements.

Combinations of the first element, the second element, and the third element include, for example, a combination of Y, Ce, and Hf, a combination of Y, Nd, and Hf, a combination of Y, Eu, and Hf, and a combination of Y and Eu. and W, a combination of Y and gadolinium (Gd) and Hf, a combination of Ga and Tb and Si, a combination of Ga and Tb and Hf, a combination of Ga and Eu and Hf, Y and Eu and Ga a combination of Ga, Yb, and Hf; a combination of Ga, Eu, and Tb; a combination of Ga, Yb, and W; a combination of Ga, Eu, and Yb; a combination of Ga, Yb, and Si; and Ce and Yb, a combination of Ga, Ce and Hf, and a combination of Ga, Nd and W.
In terms of excellent low temperature activity, the combination of Y, Eu and Hf, the combination of Ga, Tb and Hf, the combination of Ga, Eu and Hf, the combination of Y, Eu and Ga, the combination of Ga, Yb and Hf A combination of Ga, Eu, and Tb, a combination of Ga, Yb, and W, a combination of Ga, Eu, and Yb, a combination of Ga, Yb, and Si, or a combination of Ga, Ce, and Yb is preferred. , a combination of Ga, Yb and W, or a combination of Ga, Yb and Si.

The properties of the second aspect of the oxide catalyst of the present invention are not particularly limited as long as the above requirement 2 is satisfied. The above properties include all states of the oxide catalyst, such as the ratio of constituent elements of the oxide catalyst, the crystal state of the oxide catalyst, the arrangement of each element contained in the oxide catalyst, the shape and size of the oxide catalyst. etc.
The properties of the oxide catalyst are described below.

(Constituent element ratio of oxide catalyst)
The ratio of constituent elements in the second aspect of the oxide catalyst of the present invention is not particularly limited.
A second aspect of the oxide catalyst contains La, the first element, the second element, the third element, and O as constituent elements.
A preferred aspect of the ratio of the constituent elements in the second aspect is the same as in the case of including the third element in the first aspect, so the description is omitted.

(Crystal state of oxide catalyst)
The crystal state in the second aspect of the oxide catalyst of the present invention is not particularly limited.
Preferred aspects of the crystalline state in the second aspect are the same as those in the first aspect, and thus description thereof is omitted.

(Arrangement of Elements in Oxide Catalyst)
Arrangement of elements in the second aspect of the oxide catalyst of the present invention is not particularly limited.
A preferred aspect of the arrangement of the elements in the second aspect is the same as the case in which the third element is included in the first aspect, so the description is omitted.

(Shape and size of oxide catalyst)
The shape and size of the oxide catalyst in the first aspect of the oxide catalyst of the present invention are not particularly limited.
Preferred aspects of the shape and size of the oxide catalyst in the second aspect are the same as in the case of the first aspect, so description thereof is omitted.

[Requirement 3]
A third aspect of the oxide catalyst of the present invention contains at least lanthanum (La) as a contained element, and satisfies the following requirement 3.
Requirement 3: The oxide catalyst contains gallium (Ga) or yttrium (Y) as the first element, and two elements selected from Group 4 elements as the second and third elements.

Requirement 3, which the third aspect of the oxide catalyst satisfies, is preferably Requirement 3A below.
Requirement 3A: The oxide catalyst contains Ga or Y as the first element, zirconium (Zr) as the second element, and hafnium (Hf) as the third element.

Examples of combinations of the first element, the second element, and the third element include a combination of Y, titanium (Ti), and Zr, a combination of Y, Ti, and Hf, a combination of Y, Zr, and Hf, A combination of Ga, Ti and Zr, a combination of Ga, Ti and Hf, and a combination of Ga, Zr and Hf are included.
A combination of Y, Zr, and Hf is preferred from the viewpoint of excellent low-temperature activity.

The properties of the third aspect of the oxide catalyst of the present invention are not particularly limited as long as the above requirement 3 is satisfied. The above properties include all states of the oxide catalyst, such as the ratio of constituent elements of the oxide catalyst, the crystal state of the oxide catalyst, the arrangement of each element contained in the oxide catalyst, the shape and size of the oxide catalyst. etc.
Since preferred aspects of the properties of the third aspect of the oxide catalyst are the same as those of the second aspect, description thereof is omitted.

[Requirement 4]
A fourth aspect of the oxide catalyst of the present invention contains at least lanthanum (La) as a contained element, and satisfies the following requirement 4.
Requirement 4: The oxide catalyst contains gallium (Ga) or yttrium (Y) as the first element, zinc (Zn) as the second element, and gallium (Ga), yttrium (Y), and zirconium as the third element. (Zr), palladium (Pd), europium (Eu), or hafnium (Hf). However, the first element, the second element and the third element are different elements.

Requirement 4, which the fourth aspect of the oxide catalyst satisfies, is preferably Requirement 4A below.
Requirement 4A: The oxide catalyst contains Ga or Y as the first element, Zn as the second element, and Ga, Y, Zr, Pd, Eu, or Hf as the third element. However, the first element, the second element and the third element are different elements.

Combinations of the first element, the second element, and the third element include a combination of Y, Zn, and Pd, a combination of Y, Zn, and Zr, a combination of Y, Zn, and Eu, and a combination of Y, Zn, and Hf. , a combination of Y, Zn and Ga, a combination of Ga, Zn and Eu, and a combination of Ga, Zn and Hf. and Zn and Zr, a combination of Y, Zn and Hf, a combination of Y, Zn and Ga, a combination of Ga, Zn and Eu, and more preferably a combination of Ga, Zn and Eu.

The properties of the fourth aspect of the oxide catalyst of the present invention are not particularly limited as long as the above requirement 4 is satisfied. The above properties include all states of the oxide catalyst, such as the ratio of constituent elements of the oxide catalyst, the crystal state of the oxide catalyst, the arrangement of each element contained in the oxide catalyst, the shape and size of the oxide catalyst. etc.
Since preferred aspects of the properties of the fourth aspect of the oxide catalyst are the same as those of the second aspect, description thereof is omitted.

[Requirement 5]
The second aspect of the oxide catalyst of the present invention contains at least lanthanum (La) as a contained element, and satisfies requirement 5 below.
Requirement 5: The oxide catalyst contains one element selected from lanthanoid elements excluding lanthanum (La) as the first element, and one element selected from Group 2 elements as the second element, It contains magnesium (Mg), strontium (Sr), or hafnium (Hf) as the third element. However, the first element, the second element and the third element are different elements.

Requirement 5, which the fifth aspect of the oxide catalyst satisfies, is preferably Requirement 5A below.
Requirement 5A: The oxide catalyst contains neodymium (Nd), europium (Eu), or ytterbium (Yb) as the first element and magnesium (Mg), calcium (Ca), or strontium (Sr) as the second element. ) and contains Mg, Sr, or Hf as the third element. However, the first element, the second element and the third element are different elements.

Combinations of the first element, the second element, and the third element include a combination of Nd, Mg, and Hf, a combination of Nd, Ca, and Hf, a combination of Eu, Ca, and Hf, and a combination of Gd, Mg, and Hf. A combination of Nd, Sr and Hf, a combination of Eu, Mg and Hf, a combination of Eu, Sr and Hf, a combination of Ce, Mg and Sr, a combination of Nd, Mg and Sr, Eu and Mg and Sr, a combination of Eu, Mg and Ba, a combination of Yb, Mg and Sr, and a combination of Yb, Ca and Sr.
Combinations of Nd, Mg, and Hf, combinations of Eu, Ca, and Hf, combinations of Nd, Sr, and Hf, combinations of Eu, Mg, and Hf, and combinations of Yb, Mg, and Sr are preferred in terms of excellent low-temperature activity. A combination is preferred, and a combination of Eu, Ca and Hf, and a combination of Eu, Mg and Hf are more preferred.

The properties of the fifth aspect of the oxide catalyst of the present invention are not particularly limited as long as the above requirement 5 is satisfied. The above properties include all states of the oxide catalyst, such as the ratio of constituent elements of the oxide catalyst, the crystal state of the oxide catalyst, the arrangement of each element contained in the oxide catalyst, the shape and size of the oxide catalyst. etc.
Preferred aspects of the properties of the fifth aspect of the oxide catalyst are the same as those of the second aspect, so description thereof will be omitted.

<Method for producing oxide catalyst>
The method for producing the oxide particle catalyst of the present invention is not particularly limited, and known methods can be used.
Methods for producing the oxide catalyst include, for example, wet methods and dry methods.
Examples of the wet method include a method (precipitation method) in which a precursor solution containing the constituent elements is subjected to oxidation treatment, reduction treatment, etc. to generate catalyst precursor particles, and oxidation treatment is performed to obtain an oxide catalyst. .
Examples of the wet method include a method (impregnation method) in which a carrier having a desired particle size is brought into contact with a precursor solution containing the constituent elements to adsorb the precursor onto the carrier, and an oxidation treatment is performed to obtain an oxide catalyst. be done. The carrier may or may not contain the constituent elements, but preferably contains the constituent elements, more preferably La, and La ₂ O ₃ . Particles are more preferred.
The precursor solution in the wet method may contain all of the above constituent elements, or may contain a part of the above constituent elements. That is, in the precipitation method and the impregnation method, the oxide catalyst may be produced, for example, by one treatment using a precursor solution containing all of the constituent elements, and a part of the constituent elements may be The above treatment may be carried out stepwise, for example element by element, using a precursor solvent comprising:

The oxidation treatment is not particularly limited as long as the precursor particles or precursor is oxidized, and can be performed by a known method. Examples of the oxidation treatment include a method of firing at a temperature of 100 to 1500° C. in an atmosphere containing oxygen, a method of oxidation treatment using an oxidizing agent in a gas phase, and a method of treating with an oxidizing agent in a solution. methods and the like. The oxidation treatment may be performed by combining the above methods.
Moreover, before and after the oxidation treatment, a drying treatment may be performed as necessary. The drying treatment can be performed by a known method, and examples thereof include natural drying, heat drying, reduced pressure drying, solvent replacement drying, supercritical drying, freeze drying, and spray drying. The drying treatment may be performed by combining the above methods.

Dry methods include a powder method, a CVD (chemical vapor deposition) method, and a PVD (Physical vapor deposition) method. In the dry method, a method of forming a layer or particles containing the element contained above on a carrier by CVD or PVD is preferred.
As the powder method, a known method can be used, and examples thereof include a method of mixing a solid precursor containing the above-described constituent elements and performing a calcination treatment. In the firing treatment, the oxidation treatment may be performed at the same time.
A known method can be used as the CVD method, and examples thereof include a thermal CVD method, a plasma CVD method, and an atomic layer deposition (ALD) method.
A known method can be used as the PVD method, and examples thereof include a sputtering method, a vapor deposition method, and an ion plating method.
In the dry method, the oxidation treatment and the drying treatment mentioned in the wet method may be carried out.

As the method for producing the oxide catalyst, among the above methods, the above wet method is preferable, and the above impregnation method is more preferable, because the production is simple.

<Method for producing hydrocarbon>
The gas production method of the present invention includes a step (reaction step) of producing hydrocarbons having 2 carbon atoms by performing oxidative coupling (OCM) of methane using the oxide catalyst of the present invention. is a manufacturing method.
The gas production method of the present invention is not particularly limited as long as it includes the above reaction step.
The gas production method of the present invention includes, in addition to the above steps, a supply step of supplying a gas containing methane to a reaction section in which the oxide catalyst of the present invention is arranged, and a carbon number of 2 obtained through the reaction step. and a refining step of refining hydrocarbons having 2 carbon atoms from a hydrocarbon-containing gas.
Each step that can be included in the gas production method of the present invention will be described below.

[Supply process]
The supplying step supplies a gas containing methane to the reaction section in which the oxide catalyst is arranged.
The methane-containing gas may contain components other than methane, and preferably contains an oxidizing agent. The oxidizing agent is not particularly limited, but oxygen is preferred.
When the oxidizing agent is oxygen, the volume ratio of the methane content to the oxygen content is preferably 1.5 to 10.0, more preferably 1.8 to 8.0, and 2.0 to 6.0. is more preferred.
The total content of methane and oxidant is preferably 50% by volume or more, more preferably 70% by volume or more, and even more preferably 80% by volume or more, relative to the total amount of gas containing methane.
The gas containing methane may be preheated to a temperature equal to or lower than the reaction temperature in the reaction step described below.

[Reaction step]
In the reaction step, OCM is performed using the oxide catalyst of the present invention to produce hydrocarbons having 2 carbon atoms.
The temperature in the reaction step is generally 900° C. or lower, preferably 850° C. or lower, more preferably 700° C. or lower, even more preferably 650° C. or lower, particularly preferably 600° C. or lower. The lower limit is generally 400° C. or higher. According to the oxide catalyst of the present invention, OCM proceeds even at a low temperature of, for example, 600° C. or lower, and hydrocarbons having 2 carbon atoms can be efficiently produced.
When a gas containing oxygen is supplied as an oxidant, ethane and ethylene are produced as hydrocarbons having 2 carbon atoms, and at the same time, carbon dioxide, carbon monoxide, hydrogen, water, and the like are produced.
In the reaction step, the oxide catalyst is preferably brought into contact with the supplied methane-containing gas. The reaction between the oxide catalyst and the gas may be carried out in a fixed bed system or a fluidized bed system, preferably a fixed bed system.
In the case of the fixed bed system, the ratio of the amount of supplied gas to the volume of the reaction section in which the oxide catalyst is arranged, that is, the gas hourly space velocity (h ⁻¹ ) may be appropriately set. Also, the ratio of the amount of supplied gas to the cross-sectional area of the reaction section where the oxide catalyst is arranged, that is, the linear velocity (m/s) may be appropriately set.

[Purification process]
In the purification step, hydrocarbons having 2 carbon atoms are purified from the gas containing hydrocarbons having 2 carbon atoms obtained through the reaction step. Examples of hydrocarbons having 2 carbon atoms include ethane and ethylene.
A purification method is not particularly limited, and a known method can be used.
Purification methods include, for example, cryogenic separation methods, adsorption methods, and absorption methods, with cryogenic separation methods being preferred.

The present invention will be described in more detail below based on examples.
The materials, amounts used, proportions, processing details, processing procedures, etc. shown in the following examples can be changed as appropriate without departing from the gist of the present invention. Therefore, the scope of the present invention should not be construed as limited by the examples shown below.

<Preparation of oxide catalyst>
The oxide catalysts used in Examples and the oxide catalysts used in Comparative Examples were prepared by the following procedures.
The oxide catalyst is obtained by obtaining precursor particles in which a precursor containing the first element, the second element and the third element is attached to La ₂ O ₃ particles by a co-impregnation method, and calcining the precursor particles to oxidize the catalyst. obtained a catalyst.
More specifically, first, 6 mL of precursor aqueous solution containing each precursor containing the first element, the second element and the third element was prepared. The content of each precursor was adjusted so that each element contained 3 mg by weight. The reagents used as each precursor are shown below. Combinations of the first element, the second element and the third element are as shown in the table below.
1.0 g of La ₂ O ₃ (manufactured by Kanto Kagaku Co., Ltd.) was added as a carrier to the aqueous precursor solution and dispersed therein, followed by stirring at 50° C. for 6 hours. After the stirring treatment, the precursor particles were obtained by drying under reduced pressure at 80° C. with a centrifugal evaporator (CVE-3110, manufactured by Tokyo Rika Kikai Co., Ltd.). The precursor particles were further dried at 110° C. for 2 hours with a dryer (ETTAS ON-300S, manufactured by AS ONE).
The dried precursor particles were pulverized and calcined in an air atmosphere at 600° C. for 3 hours in a muffle furnace (KDF 3000plus, manufactured by Denken-Highdental) to obtain an oxide catalyst.

In addition, the oxide catalyst of the comparative example was prepared according to the above procedure.
Specifically, in the catalyst used in Comparative Example 1, the combination of the first element, the second element and the third element is as shown in the table below, and the carrier is SiO ₂ (median diameter: 46 to 50 μm, Kanto Kagaku Co., Ltd.).
The oxide catalyst used in Comparative Example 2 was prepared according to the above procedure, except that the respective precursors containing the first, second and third elements were not added.

The following precursors containing the first element, the second element and the third element were used.
・Na: _Na2CO3.10H2O , FUJIFILM Wako Pure Chemical ・Mg: _Mg ( _NO3 ) _2.6H2O , _FUJIFILM Wako Purechemical ・Si _: Si( _OC2H5 ) _{4 ,} Aldrich
・Ca: Ca(NO ₃ ) 2.4H ₂ O, FUJIFILM Wako Pure Chemical Industries, _Ltd.・Mn: _Mn (NO ₃ ) 2.4H ₂ O, FUJIFILM Wako Pure Chemical Industries _, Ltd. ・Ni: Ni(NO ₃ ) 2.6H ₂ O, FUJIFILM Wako Pure Chemicals Zn: _Zn (NO ₃ ) 2.6H ₂ O, FUJIFILM Wako Pure Chemicals Ga: Ga(NO ₃ ) _{3.nH 2} O, FUJIFILM Wako Pure Chemicals Sr: Sr( NO ₃ ) ₂ , Alfa Aeser
Y: Y( _NO3 ) _2.6H2O , _Aldrich
・Zr: ZrCl ₂ O.8H ₂ O, Kanto Chemical ・Pd: Pd(NO ₃ ) ₂ , FUJIFILM Wako Pure Chemical ・Ba: Ba(CH ₃ COO) ₂ , FUJIFILM Wako Pure Chemical ・La: La(NO _{3 )} 3.6H ₂ O _, FUJIFILM _Wako Pure Chemicals ・Ce: Ce(NO ₃ ) 3.6H ₂ O, FUJIFILM Wako Pure Chemicals ・Nd: Nd(NO ₃ ) 3.6H ₂ O, Aldrich
-Eu: Eu( _NO3 ) _3.5H2O , _Aldrich
・Tb _: Tb(NO ₃ ) _{3.6H 2} O, Kanto Kagaku ・Yb: Yb(NO ₃ ) 3.5H ₂ O, Aldrich
Hf _{: HfCl2O.8H2O} , Strem Chemicals
・W: 5( _NH4 ) _2O.12 ( _WO3 ) _.5H2O , Kanto Kagaku

<Evaluation>
For each oxide catalyst of Examples and Comparative Examples, the OCM reaction activity was evaluated by the following procedure.
The OCM reaction activity of the oxide catalyst was measured by placing the oxide catalyst in a reaction tube, supplying a gas containing methane to the temperature-controlled oxide catalyst, and analyzing the components of the discharged gas.
More specifically, a reaction tube to which a quartz tube having an inner diameter of 4 mm (gas inlet side) and an inner diameter of 2 mm (gas outlet side) are connected is placed so that the gas inlet side faces upward, and gas is introduced into the connecting portion. Glass wool was placed from the side, 50 mg of an oxide catalyst was placed on the glass wool, and further glass wool was placed. The length of the portion of the reaction tube with an inner diameter of 4 mm was 235 mm, and the length of the portion of the inner diameter of 2 mm was 150 mm.
The reaction tube in which the oxide catalyst was installed was fixed to a ring furnace (ARF-30KC, manufactured by Asahi Rika Seisakusho, the heating part was 270 mm) so that the gas introduction side was at the top, and oxygen was supplied from the gas introduction side at 20 mL / min. However, the pretreatment was carried out at a catalyst temperature of 400°C. The catalyst temperature was monitored by an R thermocouple installed near the connecting portion of the reaction tube and controlled by a control unit (model SU, manufactured by Chino Corporation).

After the pretreatment, nitrogen gas was supplied at 20 mL/min for purging, and then a mixed gas of methane, oxygen and nitrogen was supplied to the reaction tube at 21 mL/min. The mixed gas was mixed before being supplied to the reaction tube (CH ₄ /O ₂ = 2.0). A condensing water trap and a gas chromatograph (Micro GC FUSION, manufactured by INFICON) were connected to the gas outlet side of the reaction tube.
While the mixed gas was continuously supplied to the reaction tube, the temperature of the catalyst was maintained at 400° C. for 17 minutes, and the gas components were analyzed with a gas chromatograph installed on the gas outlet side of the reaction tube. Gas component analysis was performed 10 minutes after the start of holding for 17 minutes. From the obtained gas component analysis results, the yield of hydrocarbons having 2 carbon atoms at 400 ° C. (C2 compound yield), and the volume ratio of hydrocarbons having 2 carbon atoms in the reaction product (C2 compounds selectivity) was obtained. For gas analysis, Rt-Msieve 5A column (0.25 mm × 10 m, carrier gas: argon, manufactured by Restek) and Rt-U-BOND column (0.25 mm × 8 m, carrier gas: helium, Restek company) was used.
After the measurement at 400° C., the catalyst temperature was raised to 450° C. in 5 minutes, and the temperature maintenance and gas component analysis were performed in the same manner as above to obtain C2 compound yield and C2 compound selectivity. The above temperature elevation and gas component analysis were performed up to 850°C every 50°C.

Further, in the mixed gas supplied to the reaction tube, when the flow rate of each component is 14 mL/min for methane, 4 mL/min for oxygen, and 3 mL/min for nitrogen (CH ₄ / O ₂ =3.5), when the methane flow rate is 15 mL/min, the oxygen flow rate is 3 mL/min, and the nitrogen flow rate is 3 mL/min (CH ₄ /O ₂ =5.0), some The same evaluation was carried out for the examples.

<Results>
Tables 1-1 and 1-2 show the evaluation results of C2 compound yield and C2 compound selectivity at 450° C. or 550° C. for the oxide catalysts of each example and each comparative example.
The “content of each element relative to the carrier” means the content (% by mass) of each element present as an element (for example, metal) relative to the carrier.
It should be noted that Example 4 corresponds to the aspect of Requirement 1 or Requirement 1A that does not contain the third element, and "La" described as the third element is calculated as the content of La.

From the results in Tables 1-1 and 1-2, when comparing Examples and Comparative Examples, the oxide catalyst of the present invention is excellent in C2 compound yield and C2 compound selectivity at 450 ° C., and the OCM reaction is better. It was confirmed that it can proceed at low temperature.
From comparison with Examples 1 to 9, 11, 20, 25 to 29 and 31 and other Examples, the combination Y of the first element, the second element and the third element and the combination of Eu and Hf, Y and Ca and Hf, a combination of Y, Ca and Eu, a combination of Y, Ca and Ba, a combination of Nd, Mg and Hf, a combination of Eu, Ca and Hf, Y and Ca and Nd and a combination of Nd, Sr, and Hf; a combination of Eu, Mg, and Hf; a combination of Ga, Eu, and Zn; a combination of Mg, Sr, and Yb; a combination of Ga, Sr, and Yb; The combination of Yb and W, the combination of Ga, Ca and Yb, or the combination of Ga, Yb and Si, or the combination of the first element and the second element is the combination of Y and Ca , it was confirmed that at least one of the C2 compound yield and the C2 compound selectivity at 450° C. is superior.
From the comparison of Examples 2, 11, 20, 28 and 30 with other examples, the combination of Y, Ca and Hf, the combination of Eu, Mg and Hf, the combination of Ga, Zn and Eu, the combination of Ga and It was confirmed that when the combination of Yb and W or the combination of Ga, Yb and Si was used, the C2 compound yield at 450° C. was superior even when the methane/oxygen flow ratio was large.

Claims (6)

an oxide catalyst,
containing at least lanthanum as a contained element,
An oxide catalyst that meets any of the following requirements:
Requirement 1: The oxide catalyst contains gallium or yttrium as the first element, contains one element selected from Group 2 elements as the second element, and contains calcium, nickel, gallium, yttrium, as the third element, It contains barium, neodymium, europium, ytterbium, or hafnium, or does not contain the third element. However, the first element, the second element and the third element are different elements.
Requirement 2: The oxide catalyst contains gallium or yttrium as the first element, contains one element selected from lanthanide elements other than lanthanum as the second element, and contains silicon, gallium, yttrium, and cerium as the third element. , europium, terbium, ytterbium, hafnium, or tungsten. However, the first element, the second element and the third element are different elements.
Requirement 3: The oxide catalyst contains gallium or yttrium as the first element, and two elements selected from Group 4 elements as the second and third elements.
Requirement 4: The oxide catalyst contains gallium or yttrium as the first element, zinc as the second element, and gallium, yttrium, zirconium, palladium, europium, or hafnium as the third element. However, the first element, the second element and the third element are different elements.
Requirement 5: The oxide catalyst contains one element selected from lanthanoid elements other than lanthanum as a first element, one element selected from Group 2 elements as a second element, and a third Contains magnesium, strontium, or hafnium as elements. However, the first element, the second element and the third element are different elements. The oxide catalyst according to claim 1, wherein the requirements 1 to 5 are the following requirements 1A to 5A, respectively.
Requirement 1A: The oxide catalyst contains gallium or yttrium as the first element, calcium, strontium, or barium as the second element, and calcium, nickel, gallium, yttrium, barium, neodymium, and europium as the third element. , ytterbium, or hafnium, or does not contain the third element. However, the first element, the second element and the third element are different elements.
Requirement 2A: The oxide catalyst contains gallium or yttrium as the first element, cerium, europium, terbium, or ytterbium as the second element, and silicon, gallium, yttrium, cerium, europium, and terbium as the third element. , ytterbium, hafnium, or tungsten. However, the first element, the second element and the third element are different elements.
Requirement 3A: The oxide catalyst contains gallium or yttrium as the first element, zirconium as the second element, and hafnium as the third element.
Requirement 4A: The oxide catalyst contains gallium or yttrium as the first element, zinc as the second element, and gallium, yttrium, zirconium, palladium, europium, or hafnium as the third element. However, the first element, the second element and the third element are different elements.
Requirement 5A: The oxide catalyst contains neodymium, europium, or ytterbium as the first element, magnesium, calcium, or strontium as the second element, and magnesium, strontium, or hafnium as the third element. . However, the first element, the second element and the third element are different elements. The oxide catalyst comprises yttrium, europium and hafnium, yttrium, calcium and hafnium, yttrium, calcium and europium, yttrium, calcium and barium, or neodymium and magnesium. contains hafnium; contains europium, calcium, and hafnium; contains yttrium, calcium, and neodymium; contains neodymium, strontium, and hafnium; contains europium, magnesium, and hafnium; zinc, magnesium, strontium, and ytterbium; gallium, strontium, and ytterbium; gallium, ytterbium, and tungsten; gallium, calcium, and ytterbium; containing ytterbium and silicon, or
3. The oxide catalyst according to claim 1 or 2, wherein the oxide catalyst contains yttrium and calcium and does not contain any of nickel, gallium, yttrium, barium, neodymium, europium, ytterbium and hafnium. The oxide catalyst comprises yttrium, europium and hafnium, yttrium, calcium and hafnium, yttrium, calcium and europium, yttrium, calcium and barium, or europium and calcium. contains hafnium; contains yttrium, calcium, and neodymium; contains europium, magnesium, and hafnium; contains magnesium, strontium, and ytterbium; contains gallium, strontium, and ytterbium; gallium, ytterbium, and tungsten; gallium, calcium, and ytterbium; or gallium, ytterbium, and silicon; or
Oxidation according to any one of claims 1 to 3, wherein the oxide catalyst contains yttrium and calcium and does not contain any of nickel, gallium, yttrium, barium, neodymium, europium, ytterbium and hafnium. material catalyst. A method for producing hydrocarbons, comprising the step of oxidatively coupling methane using the oxide catalyst according to any one of claims 1 to 4 to produce hydrocarbons having 2 carbon atoms. 6. The method for producing hydrocarbons according to claim 5, wherein the temperature in said step is 650[deg.] C. or less.