JP7500015B2 - Solid catalyst and method for producing butadiene - Google Patents

Description

The present invention relates to a solid catalyst and a method for producing butadiene using the same.

Conventionally, 1,3-butadiene (hereinafter also abbreviated as "butadiene") has been used as a monomer as a raw material for synthetic rubbers such as butadiene rubber (BR) and styrene-butadiene rubber (SBR), and is mainly obtained as a by-product when naphtha is thermally decomposed by an ethylene cracker (naphtha cracker) to produce ethylene and propylene.
However, in recent years, the amount of butadiene produced has been decreasing due to the shift to light feed materials.
Therefore, as an alternative raw material to petroleum, a process of fermenting biomass (corn or sugarcane) and producing butadiene via butanediol, butanol, butene or ethanol is being researched.

For example, Patent Document 1 describes a solid catalyst comprising a support on which a metal (A) selected from Group 12 and a metal (B) selected from Group 4 are supported, the support being silica having an average pore size of more than 3 nm and not more than 10 nm, and a half-width in the pore size distribution of not more than 6 nm (Claim 1).

JP 2020-001001 A

The inventors have studied the solid catalyst described in Patent Document 1 and have found that there is room for improvement in the yield of butadiene.

Therefore, the objective of the present invention is to provide a solid catalyst that can improve the yield of butadiene and a method for producing butadiene using the same.

Means for Solving the Problems The present inventors have conducted intensive research to achieve the above object, and as a result have found that the yield of butadiene can be improved by using a solid catalyst supporting at least one metal selected from the group consisting of metals belonging to Groups 11 and 13, and at least one metal oxide selected from the group consisting of metals belonging to Groups 3 and 4, and have completed the present invention.
That is, the present inventors have found that the above problems can be solved by the following configuration.

[1] A solid catalyst comprising a metal (A) and a metal oxide (B) supported on a support,
The metal (A) is at least one metal selected from the group consisting of metals belonging to Groups 11 and 13;
The solid catalyst, wherein the metal oxide (B) is an oxide of at least one metal selected from the group consisting of metals belonging to Groups 3, 4 and 5.
[2] The metal (A) is a metal belonging to Group 11,
The solid catalyst according to [1], wherein the metal oxide (B) is an oxide of at least one metal selected from the group consisting of metals belonging to Groups 3 and 4.
[3] The metal (A) is silver,
The solid catalyst according to [1] or [2], wherein the metal oxide (B) is at least one selected from the group consisting of hafnium oxide, zirconium oxide and scandium oxide.
[4] The solid catalyst according to any one of [1] to [3], wherein the support is silica.
[5] The content of the metal (A) is 0.1 to 50% by mass based on the mass of the support,
The solid catalyst according to any one of [1] to [4], wherein the content of the metal oxide (B) is 0.1 to 50 mass% based on the mass of the support.
[6] A method for producing butadiene, comprising the steps of: obtaining butadiene from ethanol or a mixture of ethanol and acetaldehyde in the presence of a catalyst, the method comprising the steps of:
The method for producing butadiene, wherein the catalyst is the solid catalyst according to any one of [1] to [5].

The present invention provides a solid catalyst that can improve the yield of butadiene and a method for producing butadiene using the same.

The present invention will be described in detail below.
The following description of the components may be based on representative embodiments of the present invention, but the present invention is not limited to such embodiments.
In this specification, a numerical range expressed using "to" means a range that includes the numerical values before and after "to" as the lower and upper limits.
In this specification, "butadiene" refers to "1,3-butadiene".
In the present specification, each component may be used alone or in combination of two or more substances corresponding to each component. When two or more substances are used in combination for each component, the content of the component refers to the total content of the substances used in combination, unless otherwise specified.

[Solid catalyst]
The solid catalyst of the present invention is a solid catalyst used for producing butadiene, and is a solid catalyst comprising a metal (A) and a metal oxide (B) supported on a carrier.
In the solid catalyst of the present invention, the metal (A) is at least one metal selected from the group consisting of metals belonging to groups 11 and 13, and the metal oxide (B) is an oxide of at least one metal selected from the group consisting of metals belonging to groups 3, 4, and 5.
In the present invention, among the metals (A), the metals belonging to Group 11 are present as metals on the support, while the metals belonging to Group 13 may be present as metals on the support or as compounds such as metal oxides.

In the present invention, as described above, the yield of butadiene is improved by using a solid catalyst in which the metal (A) and the metal oxide (B) are supported on a carrier.
Although the details of this are not clear, the present inventors speculate as follows.
That is, as can be seen from a comparison of Comparative Examples 1 and 2 described later with Examples 1 and 2 in which the reaction temperature conditions were the same, when an oxide of a metal belonging to Group 12 and an oxide of a metal belonging to Group 4 were supported on a carrier, the conversion rate of the raw material was low, and therefore the yield of butadiene was considered to be low.
Therefore, in the present invention, it is considered that since at least one kind of metal (A) selected from the group consisting of metals belonging to Groups 11 and 13 is supported on the support, the raw material is efficiently converted and the selectivity of butadiene is improved, thereby improving the yield of butadiene.

[Carrier]
The carrier used in the solid catalyst of the present invention is not particularly limited as long as it can support the metal (A) and metal oxide (B) described below, and specific examples thereof include silica, alumina, magnesia, and the like.

In the present invention, it is preferable that the carrier is silica, because this increases the ethanol conversion rate and the butadiene selectivity, thereby improving the butadiene yield.

In the present invention, because the selectivity of butadiene is further increased and the yield of butadiene is further improved, it is preferable to use silica having an average pore diameter in the range of 3 to 15 nm as the carrier, and it is more preferable to use silica having an average pore diameter in the range of more than 3 nm and not more than 10 nm.
The term "average pore diameter" as used herein refers to the pore diameter showing the peak value of the pore diameter distribution curve obtained from the nitrogen adsorption isotherm by the BJH method or the DFT method.

[Metal (A)]
The metal (A) contained in the solid catalyst of the present invention is at least one metal selected from the group consisting of metals belonging to Groups 11 and 13.
Specific examples of metals belonging to Group 11 include copper (Cu), silver (Ag), and Au (gold).
Specific examples of metals belonging to Group 13 include aluminum (Al), gallium (Ga), and indium (In).

Here, the raw material of the metal belonging to Group 11 is not particularly limited, but examples thereof include nitrates and acetates of metals selected from Group 11. Specific examples thereof include Ag(NO ₃ ), CH ₃ COOAg, etc.
The raw material of the metal belonging to Group 13 is not particularly limited, but examples thereof include nitrates, oxynitrates, acetates, oxyacetates, and hydrates thereof of metals selected from Group 13. Specific examples thereof include aluminum nitrate nonahydrate, gallium nitrate hydrate, and indium nitrate trihydrate.

In the present invention, the metal (A) is preferably a metal belonging to Group 11, and more preferably silver, because this increases the ethanol conversion rate and the butadiene selectivity, thereby improving the butadiene yield.

In the present invention, the content of the metal (A) is preferably 0.1 to 50 mass%, more preferably 0.1 to 40 mass%, and even more preferably 0.2 to 30 mass%, relative to the mass of the carrier.
Here, the "content" of the metal (A) and the metal oxide (B) described later can be measured, for example, by ICP or fluorescent X-ray.

[Metal oxide (B)]
The metal oxide (B) contained in the solid catalyst of the present invention is an oxide of at least one metal selected from the group consisting of metals belonging to Groups 3, 4 and 5.
Specific examples of metals belonging to Group 3 include scandium (Sc) and yttrium (Y).
Specific examples of metals belonging to Group 4 include titanium (Ti), zirconium (Zr), and hafnium (Hf).
Specific examples of metals belonging to Group 5 include vanadium (V), niobium (Nb), and tantalum (Ta).

Here, the raw material of the metal belonging to Group 3 is not particularly limited, but examples thereof include nitrates, oxynitrates, acetates, oxyacetates, and hydrates thereof of metals selected from Group 3. Specific examples include Sc(NO ₃ ) ₂ and scandium nitrate pentahydrate.
The raw material of the metal belonging to Group 4 is not particularly limited, but examples thereof include nitrates, hydrochlorides, oxynitrates, acetates, oxyacetates, and hydrates thereof of metals selected from Group 4. Specific examples include ZrO( _NO3 ) ₂ , _ZrO ( _NO3 ) _2.2H2O , ZrO( _OCOCH3 ) ₂ , and _HfCl4 .
The raw material of the metal belonging to Group 5 is not particularly limited, but examples thereof include sulfates, oxysulfates, acetates, oxyacetates, hydrochlorides, and hydrates thereof of metals selected from Group 5. Specific examples thereof include _VOSO4 , _VOSO4.nH2O , ( _CH3COO ) _2Ta , _{VCl3 , NbCl5} , and _TaCl5 .

In the present invention, because the ethanol conversion rate and the butadiene selectivity are higher and the butadiene yield is further improved, the metal oxide (B) is preferably an oxide of at least one metal selected from the group consisting of metals belonging to Groups 3 and 4, and more preferably at least one selected from the group consisting of hafnium oxide, zirconium oxide and scandium oxide.

In addition, in the present invention, the content of the metal oxide (B) is preferably 0.1 to 50 mass%, more preferably 0.1 to 40 mass%, and even more preferably 0.2 to 30 mass%, relative to the mass of the carrier.

[Method for preparing solid catalyst]
The method for preparing the solid catalyst of the present invention is not particularly limited, and for example, known methods such as the impregnation method, the sol-gel method, etc. can be adopted. Among these, the impregnation method is preferred because the activity and selectivity of the resulting solid catalyst are high and the method is simple.
As the impregnation method, for example, known methods such as a spraying method, a coating method, a pore filling method, and a selective adsorption method can be adopted. Specifically, a method is mentioned in which the nitrate, acetate, etc. of the metal that is the raw material of the above-mentioned metal (A) and metal oxide (B) is dissolved in water, the obtained aqueous solution is impregnated into the above-mentioned carrier, and then the carrier is dried. The drying method and drying time are not particularly limited, but it is preferable to dry under reduced pressure at 60 to 80 ° C. In addition, after drying, it is preferable to calcine at a temperature of 200 to 600 ° C.
In addition to the above-mentioned preparation methods, there can also be mentioned a method in which, for example, the above-mentioned metal (A) and a metal nitrate, acetate, or the like, which are raw materials for the metal oxide (B), are mixed, and then the mixture is subjected to treatments such as heating, concentration, and hydrothermal synthesis, and then dried and fired.
The prepared catalyst may be subjected to molding, granulation, etc., before use, if necessary.

[Production method of butadiene]
The butadiene production method of the present invention (hereinafter also referred to as "the production method of the present invention") is a butadiene production method in which butadiene is obtained from ethanol or a mixture of ethanol and acetaldehyde in the presence of the above-mentioned solid catalyst of the present invention.

〔material〕
In the production method of the present invention, ethanol or a mixture of ethanol and acetaldehyde is used as the raw material for the target product, butadiene.
The raw material may be appropriately diluted and then contacted with the solid catalyst.
Specific examples of the medium for diluting the raw material (hereinafter also referred to as the "dilution medium") include inert gases such as nitrogen, argon, and helium.
The raw material may also contain impurities other than ethanol, acetaldehyde, and the dilution medium.

When a mixture of ethanol and acetaldehyde is used as a raw material in the production method of the present invention, the mass ratio of ethanol to acetaldehyde (ethanol:acetaldehyde) is not particularly limited, but is preferably in the range of 19:1 to 1:9, and more preferably in the range of 16:4 to 2:8.

[Reaction conditions, etc.]
The production method of the present invention can be carried out by a known reaction system, which may be a flow system, a batch system, or the like, but is preferably carried out in a flow system from the viewpoint of productivity.
The production method of the present invention may be carried out in either a gas phase or a liquid phase, but is preferably carried out under gas phase conditions, from the viewpoints of being able to apply a high reaction temperature and improving the conversion rate of the raw materials.
If desired, the catalyst may be reduced before the start of the reaction. For example, the catalyst may be reduced in a hydrogen stream at 200 to 500° C., and then the butadiene production step may be carried out by contacting the catalyst with the raw material.

Methods for contacting the raw material with the solid catalyst include, for example, a suspension bed method, a fluidized bed method, a fixed bed method, etc. In addition, the present invention may be either a gas phase method or a liquid phase method, but it is preferable to use a gas phase method.

When the reaction is carried out in the gas phase, the raw material gas (e.g., ethanol gas, preferably a mixture of ethanol gas and acetaldehyde gas) may be supplied to the reactor without dilution, or may be appropriately diluted with an inert gas such as nitrogen, helium, argon, or water vapor before being supplied to the reactor.

The reaction temperature is preferably from 260 to 500°C, and more preferably from 300 to 480°C.
The reaction pressure can be appropriately set within a wide range from normal pressure to high pressure, but is preferably set to 1.0 MPa or less from the viewpoints of production efficiency and apparatus configuration.

The contact time between the raw material and the solid catalyst can be controlled by adjusting the feed rate of the raw material, and the weight hourly space velocity (WHSV) per unit catalyst is preferably 1.0 to 40 g raw material/g-cat·h, and more preferably 2.0 to 20 g raw material/g-cat·h.

After the reaction is complete, the reaction products can be separated and purified into light gases, C4 fractions, heavy fractions, water, ethanol, acetaldehyde, etc., using separation methods such as distillation, extraction, membrane separation, or a combination of these.

The present invention will be described in more detail below with reference to examples. The materials, amounts used, ratios, processing contents, processing procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the examples shown below.

Example 1
Aqueous solution A1 was prepared by dissolving 0.211 g of AgNO ₃ (Ag salt) in 5 ml of water.
Separately, 0.204 g of HfCl ₄ (Hf salt) was dissolved in 5 ml of water to prepare an aqueous solution B1.
The prepared aqueous solution A1 was impregnated into mesoporous silica (manufactured by Fuji Silysia Ltd., product name: CARiACT G-6, average pore size: 6 nm), which was then dried at 110° C. for 4 hours and further calcined at 500° C. for 4 hours.
After the calcination, the sample was impregnated with the prepared aqueous solution B1, dried at 110° C. for 4 hours, and further calcined at 500° C. for 4 hours to prepare a solid catalyst 1 in which Ag and HfO ₂ were supported on silica.
Table 1 below shows the types and amounts of metals supported.

0.3 g of the prepared solid catalyst 1 was packed into a fixed-bed flow reactor, _N2 gas was flowed at 5 to 15 ml/min, and ethanol (EtOH) was added to the _N2 gas flow at a rate of 0.03 ml/min. The reaction was carried out at a reaction temperature of 425° C. under atmospheric pressure and a weight hourly space velocity (WHSV) of 5.0 g-raw material/g-cat·h. Table 1 below shows the raw materials, reaction temperature, and weight hourly space velocity (WHSV).
The reaction was carried out for 2 hours, and the resulting product was analyzed using a gas chromatograph (manufactured by Shimadzu Corporation).
The conversion rate of the raw material, butadiene (BD) selectivity, BD yield, and BD productivity were calculated according to the following formulas. These results are shown in Table 1 below.
Conversion rate of raw material=(amount of raw material input−amount of unreacted raw material distillate)/(amount of raw material input)×100(%)
BD selectivity=(amount of butadiene produced)/(amount of raw material input−amount of unreacted raw material distilled)×100(C-mol%)
BD yield = (conversion rate of raw material) x (BD selectivity) ÷ 100 (C-mol%)
BD productivity=(mass of butadiene produced per hour)/(mass of catalyst used)(g-BD/g-cat·h)

Example 2
The raw material conversion, butadiene (BD) selectivity, BD yield, and BD productivity were calculated in the same manner as in Example 1, except that the reaction temperature was changed to the temperature (400° C.) shown in Table 1 below. These results are shown in Table 1 below.

Example 3
The raw material conversion, butadiene (BD) selectivity, BD yield, and BD productivity were calculated in the same manner as in Example 1, except that the reaction temperature was changed to the temperature (375° C.) shown in Table 1 below. These results are shown in Table 1 below.

Example 4
A solid catalyst ₄ in which Ag and _ZrO2 were supported on silica was prepared in the same manner as in Example 1, except that an aqueous solution B4 in which 0.147 g of ZrO( _NO3 ) _2.2H2O (Zr salt) was dissolved in 5 ml of water was used instead of the aqueous solution B1.
In addition, for the prepared solid catalyst 4, the raw material conversion rate, butadiene (BD) selectivity, BD yield, and BD productivity were calculated in the same manner as in Example 1. These results are shown in Table 1 below.

Example 5
The raw material conversion, butadiene (BD) selectivity, BD yield, and BD productivity were calculated in the same manner as in Example 4, except that the reaction temperature was changed to the temperature (400° C.) shown in Table 1 below. These results are shown in Table 1 below.

Example 6
The raw material conversion, butadiene (BD) selectivity, BD yield, and BD productivity were calculated in the same manner as in Example 4, except that the reaction temperature was changed to the temperature (375° C.) shown in Table 1 below. These results are shown in Table 1 below.

Example 7
A solid catalyst _{7 in which Ag and Sc2O3 were} supported on silica was prepared in the same manner as in Example 1, except that an aqueous solution B7 in which 0.108 g of Sc( _NO3 ) ₂ (Sc raw material) was dissolved in 5 ml of water was used instead of the aqueous solution B1.
In addition, for the prepared solid catalyst 7, the raw material conversion rate, butadiene (BD) selectivity, BD yield, and BD productivity were calculated in the same manner as in Example 2. These results are shown in Table 1 below.

Comparative Example 1
An aqueous solution was prepared by dissolving 0.037 g of Zn(NO ₃ ) ₂ .6H ₂ O (Zn salt) and 0.022 g of ZrO(NO ₃ ) ₂ .2H ₂ O (Zr salt) in 1 ml of water.
The prepared aqueous solution was impregnated into silica (manufactured by Fuji Silysia Chemical Ltd., product name: CARiACT G-6, average pore size: 6 nm, half width: 1.6 nm), which was then dried at 110°C for 4 hours and calcined at 500°C for 4 hours to prepare a solid catalyst C1 in which ZnO and _ZrO2 were supported on silica.
In addition, for the prepared solid catalyst C1, the raw material conversion rate, butadiene (BD) selectivity, BD yield, and BD productivity were calculated in the same manner as in Example 1. These results are shown in Table 1 below.

Comparative Example 2
The raw material conversion, butadiene (BD) selectivity, BD yield, and BD productivity were calculated in the same manner as in Comparative Example 1, except that the reaction temperature was changed to the temperature (400° C.) shown in Table 1 below. These results are shown in Table 1 below.

Comparative Example 3
An aqueous solution was prepared by dissolving 0.183 g of Zn(NO ₃ ) _{2.6H 2} O (Zn salt) and 0.125 g of Mg(NO ₃ ) _{2.6H 2} O (Mg salt) in 5 ml of water.
The prepared aqueous solution was impregnated into mesoporous silica (manufactured by Fuji Silysia Chemical Ltd., product name: CARiACT G-6, average pore size: 6 nm, half width: 1.6 nm), which was then dried at 110°C for 4 hours and calcined at 500°C for 4 hours to prepare solid catalyst C3 in which ZnO and MgO were supported on silica.
In addition, for the prepared solid catalyst C3, the raw material conversion rate, butadiene (BD) selectivity, BD yield, and BD productivity were calculated in the same manner as in Example 1. These results are shown in Table 1 below.

Comparative Example 4
The raw material conversion, butadiene (BD) selectivity, BD yield, and BD productivity were calculated in the same manner as in Comparative Example 3, except that the reaction temperature was changed to the temperature (400° C.) shown in Table 1 below. These results are shown in Table 1 below.

From the results shown in Table 1, it was found that the solid catalyst supporting a metal of Group 12 and an oxide of a metal of Group 4 gave a butadiene yield of less than 40% (Comparative Examples 1 and 2).
It was also found that the solid catalyst supporting a Group 12 metal and an oxide of a Group 2 metal gave a butadiene yield of about 10% (Comparative Examples 3 and 4).
In contrast, it was found that the yield of butadiene was improved by using a solid catalyst supporting at least one metal selected from the group consisting of metals belonging to Groups 11 and 13 and an oxide of at least one metal selected from the group consisting of metals belonging to Groups 3 and 4 (Examples 1 to 7).

Claims (6)

A solid catalyst for use in the production of butadiene, comprising a metal (A) and a metal oxide (B) supported on a support, comprising:
The metal (A) is at least one metal selected from the group consisting of metals belonging to Groups 11 and 13;
The solid catalyst, wherein the metal oxide (B) is an oxide of at least one metal selected from the group consisting of scandium, yttrium and hafnium. The metal (A) is a metal belonging to Group 11,
2. The solid catalyst according to claim 1, wherein the metal oxide (B) is an oxide of at least one metal selected from the group consisting of scandium, yttrium and hafnium. The metal (A) is silver,
3. The solid catalyst according to claim 1, wherein the metal oxide (B) is at least one selected from the group consisting of hafnium oxide and scandium oxide. The solid catalyst according to any one of claims 1 to 3, wherein the support is silica. The content of the metal (A) is 0.1 to 50% by mass based on the mass of the support,
The solid catalyst according to any one of claims 1 to 4, wherein the content of the metal oxide (B) is 0.1 to 50 mass% based on the mass of the support. A method for producing butadiene, comprising the steps of: obtaining butadiene from ethanol or a mixture of ethanol and acetaldehyde in the presence of a catalyst, the method comprising the steps of:
The method for producing butadiene, wherein the catalyst is the solid catalyst according to any one of claims 1 to 5.