TECHNICAL FIELD

The present invention relates to a catalyst, a method for producing the same, and a method for producing a diene compound using the catalyst.

Priority is claimed on Japanese Patent Application No. 2018-003731, filed on Jan. 12, 2018, the content of which is incorporated herein by reference.

BACKGROUND ART

Butadiene such as 1,3-butadiene, which is a representative example of diene compounds, is used as a raw material for styrene-butadiene rubber (SBR) and the like. Conventionally, butadiene has been purified from the C4 fraction. The C4 fraction is a fraction obtained as a by-product in naphtha cracking for producing ethylene from petroleum. However, the use of petroleum has decreased as a result of increased use of shale gas. Consequently, the butadiene production by naphtha cracking of petroleum has also decreased. Therefore, there is a demand for an alternative method for producing diene compounds such as 1,3-butadiene.

For example, Patent Document 1 discloses an invention relating to a metal-impregnated silica catalyst for selectively converting ethanol into butadiene. More specifically, Patent Document 1 describes a butadiene synthesis catalyst including Hf and two or more catalytically active metals M1 and M2, wherein the two or more catalytically active metals M1 and M2 are selected from the group consisting of Zr, Zn, Cu, and combinations thereof, provided that M1 and M2 are different.

Patent Document 1 describes a method for synthesizing butadiene, which includes (i) providing a gas stream G-1 containing ethanol and optional acetaldehyde, and (ii) contacting the gas stream G-1 with the butadiene synthesis catalyst to obtain a gas stream G-2 containing butadiene.

Patent Document 1 describes that the method for synthesizing butadiene achieves a butadiene selectivity of at least 10%.

DESCRIPTION OF PRIOR ART

Patent Document

Patent Document 1: International Patent Application Publication No. 2014/199349

DISCLOSURE OF INVENTION

Problems to be Solved by the Invention

Although the invention described in Patent Document 1 enables butadiene synthesis using ethanol as a raw material gas, it is necessary to reduce the ethanol concentration in the raw material gas. For this reason, according to the invention described in Patent Document 1, the yield of butadiene per unit time is low, and it is difficult to increase the production efficiency of butadiene.

In this situation, the object of the present invention is to provide a catalyst that can efficiently produce a diene compound even when the alcohol concentration in the raw material gas is high.

Means to Solve the Problems

The present inventors have made intensively studies to solve the above-mentioned problems. As a result, they have found that the above problems can be solved by a catalyst obtained by contacting an oxide containing specific metals with a porous carrier, and have completed the present invention.

That is, the embodiments of the present invention are as follows.

[1] A catalyst including:

a porous carrier including at least one element X selected from the group consisting of elements belonging to Groups 13 and 14 of the periodic table;

an oxide of at least one metal element A selected from the group consisting of elements belonging to Groups 3 to 6 of the periodic table; and

at least one oxide of a metal element B selected from the group consisting of elements belonging to Group 2 and Groups 7 to 12 of the periodic table, wherein at least a part of the oxide of the metal element A is bonded to the porous carrier.

[2] The catalyst according to [1], wherein a ratio of the number of moles of the metal element A to the number of moles of the element X (metal element A/element X) is 0.001 to 1.

[3] The catalyst according to [1] or [2], wherein a ratio of the number of moles of the metal element B to the number of moles of the element A (metal element B/element A) is 0.1 to 10.

[4] The catalyst according to any one of [1] to [3], wherein the porous carrier has mesopores.

[5] The catalyst according to any one of [1] to [4], which is a catalyst for synthesizing a diene compound from a raw material gas containing an alcohol.

[6] The catalyst according to [5], wherein the raw material gas is ethanol, or a mixture of ethanol and acetaldehyde.

[7] A method for producing the catalyst of any one of [1] to [6], comprising:

reacting a compound containing the metal element A with the porous carrier to prepare a catalyst precursor in which at least a part of the oxide of the metal element A is bonded to the porous carrier; and

reacting the catalyst precursor with a compound containing the metal element B.

[8] The method according to [7], wherein the catalyst precursor is prepared by a method including:

impregnating a porous carrier with a first solution containing a compound containing the metal element A to obtain a solution containing an impregnated product; and

separating the impregnated product from the first solution; and

calcining the impregnated product.

[9] A method for producing a diene compound, including contacting the catalyst of any one of [1] to [6] with a raw material gas containing an alcohol to obtain a diene compound.

[10] The method according to [9], wherein a reaction temperature for obtaining the diene compound is 200 to 600° C.

Effect of the Invention

The catalyst of the present invention enables efficient production of a diene compound even when the alcohol concentration in the raw material gas is high.

