JP2024048691A - Catalyst and method for producing butadiene - Google Patents

Abstract

[Problem] To provide a catalyst capable of producing butadiene at a higher yield (ethanol conversion rate and/or butadiene selectivity) using ethanol as a raw material, and a method for producing butadiene using such a catalyst. [Solution] According to one aspect of the present invention, a catalyst used for producing butadiene directly from ethanol is provided. The catalyst in this catalyst has an active component that exhibits catalytic activity. The active component includes element A selected from the elements belonging to Group 3 of the periodic table, element B selected from the elements belonging to Group 4 of the periodic table, element C selected from the elements belonging to Group 12 of the periodic table, and element D selected from the elements belonging to Groups 5 and 11 of the periodic table. [Selected Figure] None

Description

The present invention relates to a catalyst and a method for producing butadiene, and more specifically to a catalyst capable of producing butadiene directly from ethanol, and a method for producing butadiene using such a catalyst.

In recent years, the production of butadiene, which is useful as a raw material for synthetic rubber, from ethanol has been investigated (see Patent Document 1).
The catalyst described in Patent Document 1 is a solid catalyst in which metal (A), metal (B) and metal (C) are supported on a carrier. In this solid catalyst, metal (A) is a metal selected from Group 12, metal (B) is a metal selected from Group 4, and metal (C) is at least one metal selected from the group consisting of Group 2, scandium, cerium, neodymium, gadolinium, Group 6, Group 7, Group 9, palladium, and Group 13.

JP 2020-998 A

Although the catalyst described in Patent Document 1 can produce butadiene in a relatively high yield, there is a demand for the development of a catalyst that can produce butadiene at an even higher flow rate.
In view of the above circumstances, the present invention provides a catalyst capable of producing butadiene in a higher yield (ethanol conversion rate and/or butadiene selectivity) using ethanol as a raw material, and a method for producing butadiene using such a catalyst.

According to one aspect of the present invention, a catalyst is provided for use in producing butadiene directly from ethanol. The catalyst in this catalyst has an active component that exhibits catalytic activity. The active component includes element A selected from the elements belonging to Group 3 of the periodic table, element B selected from the elements belonging to Group 4 of the periodic table, element C selected from the elements belonging to Group 12 of the periodic table, and element D selected from the elements belonging to Groups 5 and 11 of the periodic table.

According to this embodiment, butadiene can be produced directly from ethanol with a higher yield.

The catalyst and the method for producing butadiene of the present invention will be described in detail below based on preferred embodiments.
1.1 Catalyst The catalyst of the present invention is used to produce butadiene directly from ethanol (i.e., it is used in the method for producing butadiene of the present invention).
In this case, preferably, ethanol is directly converted into butadiene by passing a gas containing ethanol through a reaction bed (reaction vessel) in which the catalyst of the present invention is packed in a reaction tube.

The catalyst of the present invention has an active component (catalytic component) that exhibits catalytic activity.
The active ingredient comprises element A selected from the elements belonging to Group 3 of the periodic table, element B selected from the elements belonging to Group 4 of the periodic table, element C selected from the elements belonging to Group 12 of the periodic table, and element D selected from the elements belonging to Groups 5 and 11 of the periodic table.
The catalyst containing these elements A to D makes it possible to produce butadiene from ethanol in a sufficiently high yield.

Here, the yield of butadiene from ethanol is a value calculated by multiplying the ratio of ethanol converted to other compounds (ethanol conversion rate) by the ratio of butadiene to the other converted compounds (butadiene selectivity).
Therefore, a high yield of butadiene includes any of the cases where the ethanol conversion is high, the selectivity of butadiene is high, and both the conversion of ethanol and the selectivity of butadiene are high.

[Element A]
The element A is an element selected from the elements belonging to Group 3 of the periodic table. In the following, an "element belonging to Group X of the periodic table" will be simply referred to as an "element of Group X".
Examples of Group 3 elements include scandium (Sc), yttrium (Y), lanthanum (La), cerium (Ce), samarium (Sm), and gadolinium (Gd).
Among these, yttrium and lanthanum are preferred as the Group 3 elements since they provide a higher yield of butadiene.

The amount of yttrium contained in the active component is preferably 2 mol % or more and 25 mol % or less, and more preferably 7 mol % or more and 25 mol % or less.
The amount of lanthanum contained in the active ingredient is preferably 0 mol% or more and 20 mol% or less, more preferably 0 mol% or more and 13 mol% or less, even more preferably 0 mol% or more and 12 mol% or less, and particularly preferably 0 mol% or more and 10 mol% or less.
The amount of Group 3 element contained in the active ingredient is preferably 9 mol% or more and 32 mol% or less, more preferably 9 mol% or more and 29 mol% or less, even more preferably 14 mol% or more and 29 mol% or less, and particularly preferably 14 mol% or more and 25 mol% or less.

[Element B]
The element B is an element selected from the Group 4 elements.
Examples of Group 4 elements include titanium (Ti), zirconium (Zr), and hafnium (Hf).
Among these, zirconium and hafnium are preferred as the Group 4 elements since they provide a higher yield of butadiene.

The amount of zirconium contained in the active component is preferably 0 mol % or more and 33 mol % or less, more preferably 0 mol % or more and 18 mol % or less, and even more preferably 0 mol % or more and 14 mol % or less.
The amount of hafnium contained in the active component is preferably 0 mol % or more and 24 mol % or less, and more preferably 7 mol % or more and 24 mol % or less.
The amount of the Group 4 element contained in the active component is preferably 4 mol% or more and 42 mol% or less, more preferably 7 mol% or more and 38 mol% or less, even more preferably 7 mol% or more and 32 mol% or less, and particularly preferably 7 mol% or more and 27 mol% or less.

[Element C]
The element C is an element selected from the Group 12 elements.
Examples of Group 12 elements include zinc (Zn), cadmium (Cd), and mercury (Hg).
Among these, zinc is preferred as the Group 12 element since it leads to a higher yield of butadiene.

The amount of zinc contained in the active ingredient is preferably 1 mol % or more and 26 mol % or less, more preferably 6 mol % or more and 26 mol % or less, and even more preferably 6 mol % or more and 16 mol % or less.
The amount of the Group 12 element contained in the active component is preferably 1 mol % or more and 26 mol % or less, more preferably 6 mol % or more and 26 mol % or less, and even more preferably 6 mol % or more and 16 mol % or less.

The total amount of element A, element B, and element C contained in the active ingredient is preferably 40 mol% or more, more preferably 45 mol% to 80 mol%, even more preferably 50 mol% to 75 mol%, and particularly preferably 55 mol% to 70 mol%. In this case, the butadiene yield (particularly the ethanol conversion rate) can be further increased.

[Element D]
The element D is an element selected from the group 5 elements and the group 11 elements.
Examples of Group 5 elements include vanadium (V), niobium (Nb), and tantalum (Ta).
Examples of Group 11 elements include copper (Cu), silver (Ag), and gold (Au).
Among these, niobium is preferred as the Group 5 element, and copper and silver are preferred as the Group 11 elements, because the yield of butadiene is higher.

The amount of niobium contained in the active component is preferably 0 mol % or more and 12 mol % or less, and more preferably 1 mol % or more and 12 mol % or less.
The amount of the Group 5 element contained in the active component is preferably 0 mol % or more and 12 mol % or less, and more preferably 1 mol % or more and 12 mol % or less.

The amount of copper contained in the active component is preferably 0 mol % or more and 20 mol % or less, more preferably 5 mol % or more and 8 mol % or less, and even more preferably 7 mol % or more and 8 mol % or less.
The amount of silver contained in the active component is preferably 0 mol % or more and 12 mol % or less, more preferably 0 mol % or more and 7 mol % or less, and even more preferably 4 mol % or more and 7 mol % or less.
The amount of the Group 11 element contained in the active component is preferably 0 mol% or more and 27 mol% or less, more preferably 4 mol% or more and 24 mol% or less, even more preferably 7 mol% or more and 15 mol% or less, and particularly preferably 11 mol% or more and 15 mol% or less.

[Element E]
From the viewpoint of further increasing the yield of butadiene, it is preferable that the active component further contains element E.
The element E is an element selected from the Group 6 elements.
Examples of Group 6 elements include chromium (Cr), molybdenum (Mo), and tungsten (W).
Among these, chromium and molybdenum are preferred as the Group 6 elements since they provide a higher yield of butadiene.

The amount of chromium contained in the active component is preferably 0 mol % or more and 12 mol % or less, more preferably 0 mol % or more and 9 mol % or less, and even more preferably 0 mol % or more and 1 mol % or less.
The amount of molybdenum contained in the active component is preferably 0 mol % or more and 14 mol % or less, more preferably 0 mol % or more and 12 mol % or less, and even more preferably 0 mol % or more and 1 mol % or less.
The amount of the Group 6 element contained in the active component is preferably 0 mol % or more and 24 mol % or less, more preferably 1 mol % or more and 10 mol % or less, and even more preferably 1 mol % or more and 2 mol % or less.

[Element F]
From the viewpoint of further increasing the yield of butadiene, it is preferable that the active component further contains the element F.
The element F is an element selected from the Group 2 elements.
Examples of Group 2 elements include beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba).
Among these, magnesium is preferred as the Group 2 element since it leads to a higher yield of butadiene.

The amount of magnesium contained in the active ingredient is preferably 0 mol % or more and 26 mol % or less, and more preferably 8 mol % or more and 26 mol % or less.
The amount of the Group 2 element contained in the active component is preferably 0 mol % or more and 26 mol % or less, and more preferably 8 mol % or more and 26 mol % or less.

[Element G]
From the viewpoint of further increasing the yield of butadiene, it is preferable that the active component further contains element G.
The element G is an element selected from the Group 13 elements.
Examples of Group 13 elements include boron (B), aluminum (Al), gallium (Ga), indium (In), and thallium (Tl).
Among these, aluminum and gallium are preferred as the Group 13 elements since they provide a higher yield of butadiene.

The amount of aluminum contained in the active component is preferably 0 mol% or more and 10 mol% or less, more preferably 0 mol% or more and 9 mol% or less, even more preferably 0 mol% or more and 8 mol% or less, and particularly preferably 0 mol% or more and 7 mol% or less.
The amount of gallium contained in the active ingredient is preferably 0 mol% or more and 43 mol% or less, more preferably 0 mol% or more and 8 mol% or less, even more preferably 0 mol% or more and 2 mol% or less, and particularly preferably 1 mol% or more and 2 mol% or less.
The amount of the Group 13 element contained in the active component is preferably 0 mol% or more and 47 mol% or less, more preferably 0 mol% or more and 13 mol% or less, even more preferably 0 mol% or more and 10 mol% or less, and particularly preferably 2 mol% or more and 4 mol% or less.

[Element H]
From the viewpoint of further increasing the yield of butadiene, it is preferable that the active component further contains the element H.
The element H is an element selected from the group 10 elements.
Examples of Group 10 elements include nickel (Ni), palladium (Pd), and platinum (Pt).
Among these, nickel is preferred as the Group 10 element since it leads to a higher yield of butadiene.

The amount of nickel contained in the active component is preferably 0 mol % or more and 16 mol % or less, and more preferably 0 mol % or more and 8 mol % or less.
The amount of the Group 10 element contained in the active component is preferably 0 mol % or more and 16 mol % or less, and more preferably 0 mol % or more and 8 mol % or less.

The combination of elements that can produce a catalyst with a particularly high butadiene yield is as follows:
I: a combination of element A (Group 3 element), element B (Group 4 element), element C (Group 12 element), element D (Group 5 element and/or Group 11 element), element E (Group 6 element), element F (Group 2 element), and element G (Group 13 element);
II: a combination of element A (Group 3 element), element B (Group 4 element), element C (Group 12 element), element D (Group 5 element and/or Group 11 element), element E (Group 6 element), element F (Group 2 element), element G (Group 13 element), and element H (Group 10 element);
III: a combination of element A (Group 3 element), element B (Group 4 element), element C (Group 12 element), element D (Group 5 element and/or Group 11 element), element F (Group 2 element), and element G (Group 13 element);
IV: a combination of element A (Group 3 element), element B (Group 4 element), element C (Group 12 element), element D (Group 5 element and/or Group 11 element), element E (Group 6 element), element G (Group 13 element), and element H (Group 10 element);
V: a combination of element A (Group 3 element), element B (Group 4 element), element C (Group 12 element), element D (Group 5 element and/or Group 11 element), element E (Group 6 element), element F (Group 2 element), and element H (Group 10 element);
Examples include:

Among these, the combination of elements is preferably the combination of II: element A (group 3 element), element B (group 4 element), element C (group 12 element), element D (group 5 element and/or group 11 element), element E (group 6 element), element F (group 2 element), element G (group 13 element), and element H (group 10 element), and more preferably the combination of element A (group 3 element), element B (group 4 element), element C (group 12 element), element D (group 5 element and group 11 element), element E (group 6 element), element F (group 2 element), element G (group 13 element), and element H (group 10 element).

The amount of each element contained in the active ingredient is preferably in the range of 1, more preferably in the range of 2, even more preferably in the range of 3, particularly preferably in the range of 4, and most preferably in the range of 5 in Table 1 below.
In addition, "Y to Z" in Table 1 indicates Y or more and Z or less. The same applies hereinafter.

Specific combinations of elements that are suitable include magnesium (Mg), zinc (Zn), copper (Cu), silver (Ag), nickel (Ni), aluminum (Al), lanthanum (La), yttrium (Y), hafnium (Hf), zirconium (Zr), chromium (Cr), gallium (Ga), niobium (Nb), and molybdenum (Mo).

The amount of each element contained in the active ingredient is preferably in the range of 1, more preferably in the range of 2, even more preferably in the range of 3, particularly preferably in the range of 4, and most preferably in the range of 5 in Table 2 below.

The catalyst of the present invention may be composed of the active component alone, or may be composed of the active component and a carrier supporting the active component. In this case, the shape retention of the catalyst can be improved and the specific surface area of the catalyst can be easily adjusted.
When the catalyst has a carrier, the amount of the active component supported on 1 g of the carrier (hereinafter also referred to as "supported amount") is preferably 1.05 mmol to 1.56 mmol, more preferably 1.05 mmol to 1.47 mmol, and even more preferably 1.05 mmol to 1.46 mmol. If the catalyst has a loading amount (loading) of the active component within the above range, it is possible to further improve the yield of butadiene while maintaining its high shape retention.

The constituent material of the carrier is not particularly limited as long as it is a compound that is not easily denatured in response to contact with a gas containing ethanol or reaction conditions, and examples of the material include inorganic materials such as oxides, nitrides, oxynitrides, and carbides, and carbon materials (graphite, graphene, etc.).
Among these, the support is preferably an oxide, more preferably an oxide containing at least one of magnesium (Mg), titanium (Ti), zirconium (Zr), aluminum (Al) and silicon (Si), and even more preferably silicon oxide. These oxides are preferred because they have high thermal stability and can easily support the active component stably.

The support may be a dense body, but is preferably a porous body.
In this case, the average pore diameter of the carrier is preferably 2 nm to 50 nm, more preferably 2 nm to 30 nm, and even more preferably 2 nm to 15 nm, in which case the amount of the active component supported can be sufficiently increased, and the yield of butadiene produced by the catalyst can be further improved.
The total pore volume of the carrier is preferably 0.1 mL/g or more and 2 mL/g or less, more preferably 0.5 mL/g or more and 2 mL/g or less, and even more preferably 0.75 mL/g or more and 2 mL/g or less. In this case, the ethanol-containing gas can be guided to the inside of the catalyst, and the contact area between the ethanol and the active component can be sufficiently secured, thereby further increasing the yield of butadiene.

The BET specific surface area of the carrier is preferably ⁵⁰ m2/g or more and 1200 ^m2 /g or less, more preferably ⁵⁰ m2/g or more and 1000 ^m2 /g or less, and even more preferably ¹⁰⁰ m2/g or more and ¹⁰⁰⁰ m2/g or less. If the BET specific surface area is within the above range, the above effects can be further improved.
The shape of the carrier is not particularly limited, but is preferably, for example, granular.
Here, granular is a concept including powder, particle, lump, pellet, etc., and the form may be any of spherical, plate-like, polygonal, crushed, columnar, needle-like, and scale-like.

The average particle size of the carrier is preferably 1 μm to 10 mm, more preferably 100 μm to 10 mm, and even more preferably 100 μm to 5 mm. If the catalyst has such an average particle size, it is easy to adjust the BET specific surface area to the above range.
In this specification, the average particle size means the average particle size of 200 randomly selected carriers in one visual field observed under an electron microscope. In this case, the "particle size" means the maximum distance between two points on the contour line of the carrier. In addition, when the carrier is cylindrical, the maximum distance between two points on the contour line of the end face is taken as the "particle size".
Furthermore, the average particle size refers to the average particle size of secondary particles when the primary particles are aggregated, for example in a lump form.

The yield of butadiene using the catalyst of the present invention is preferably 40% or more, more preferably 45% or more, more preferably 50% or more, even more preferably 55% or more, still more preferably 60% or more, particularly preferably 65% or more, and most preferably 70% or more.
Incidentally, no catalyst capable of producing such a high yield of butadiene has been found so far.

1.2 Method for Producing Catalyst Next, a method for producing the catalyst will be described.
The method for producing the catalyst is not particularly limited, but examples thereof include an impregnation method, a sol-gel method, a coprecipitation method, a solid phase method, and a hydrothermal synthesis method.
As an example, the catalyst can be produced as follows. First, a salt of an element (constituent element) constituting the active component is dissolved in a suitable solvent to prepare a solution. Next, a carrier is added to this solution as necessary, and the solution is dried under reduced pressure while being heated with stirring, thereby impregnating the metal salt. Thereafter, the solution is dried at a temperature higher than the heating temperature as necessary, and further calcined. That is, the catalyst of the present invention can be produced easily and reliably by the so-called impregnation method.
In addition, for example, citric acid, acetic acid, malic acid, tartaric acid, hydrochloric acid, nitric acid, or a mixture thereof may be added to the solution.

Examples of salts of the constituent elements include nitrates, sulfates, chlorides, hydroxides, carbonates, and compounds thereof, among which nitrates and chlorides are preferred. Hydrates of the salts of the elements may also be used as needed.
In the case of nitrates, water is preferably used as the solvent, and in the case of chlorides, alcohols such as ethanol are preferably used as the solvent.

The temperature during impregnation (drying temperature) is preferably 20° C. or higher and 150° C. or lower, more preferably 50° C. or higher and 100° C. or lower. When the solvent is water, the drying temperature is about 90° C., and when the solvent is ethanol, the drying temperature is about 70° C.
The time for impregnation (drying time) is preferably from 0.5 hours to 15 hours, more preferably from 1 hour to 10 hours.
By drying in this manner, the support impregnated with the metal salt can be dried uniformly. The drying may be performed under atmospheric pressure or under reduced pressure, but is preferably performed under reduced pressure.

The temperature during calcination of the carrier impregnated with the metal salt (calcination temperature) is preferably 200°C or higher and 800°C or lower, more preferably 300°C or higher and 600°C or lower.
The time for calcining the carrier impregnated with the metal salt (calcination time) is preferably 1 hour or more and 24 hours or less, more preferably 1.5 hours or more and 20 hours or less. The metal salt can be converted into an active component by calcination. Moreover, calcination under the above calcination conditions can prevent excessive particle growth of the active component (catalyst).
Until the calcination temperature is reached, the temperature is increased at a rate of 1° C./min to 20° C./min, preferably 2° C./min to 10° C./min, which promotes the growth of particles of the active component (catalyst) and also prevents cracking of the crystals (particles).

Specific examples of salts of the constituent elements include magnesium (II) nitrate hexahydrate, zinc nitrate hexahydrate, copper (II) nitrate trihydrate, silver nitrate, nickel (II) nitrate hexahydrate, aluminum nitrate nonahydrate, lanthanum (III) nitrate hexahydrate, yttrium (III) nitrate hexahydrate, hafnium (IV) chloride, zirconium nitrate dihydrate, zirconium (IV) chloride, zirconium oxychloride octahydrate, chromium (III) nitrate nonahydrate, chromium (III) chloride hexahydrate, gallium (III) nitrate, niobium (V) chloride, and molybdenum (V) chloride.

[Production method of butadiene]
The method for producing butadiene of the present invention is a method for directly producing butadiene by contacting ethanol with a catalyst. Specifically, the method is carried out by supplying a gas containing ethanol to a reaction bed in which a reaction tube is filled with the catalyst.
The catalyst used in the method for producing butadiene of the present invention has an active component exhibiting catalytic activity, which includes element A selected from the Group 3 elements, element B selected from the Group 4 elements, element C selected from the Group 12 elements, and element D selected from the Groups 5 and 11 elements.
The preferred configuration, shape, characteristics, etc. of the catalyst are the same as those described above.

The temperature (reaction temperature) when ethanol is brought into contact with the catalyst is preferably 200°C or higher and 600°C or lower, and more preferably 300°C or higher and 500°C or lower.
The concentration of ethanol contained in the gas to be supplied is preferably 5% by volume or more and 20% by volume or less.
The flow rate of the gas to be supplied is preferably 1 mL/min or more and 30 mL/min or less, and more preferably 5 mL/min or more and 25 mL/min or less.
By setting such conditions, the yield of butadiene can be sufficiently increased.

As described above, the present invention can provide a catalyst capable of producing butadiene in a higher yield (ethanol conversion rate and/or butadiene selectivity) using ethanol as a raw material, and a method for producing butadiene using such a catalyst.
Furthermore, it may be provided in the following aspects:

(1) A catalyst used to directly produce butadiene from ethanol, the catalyst having an active component exhibiting catalytic activity, the active component including element A selected from the elements belonging to Group 3 of the periodic table, element B selected from the elements belonging to Group 4 of the periodic table, element C selected from the elements belonging to Group 12 of the periodic table, and element D selected from the elements belonging to Groups 5 and 11 of the periodic table.

(2) The catalyst described in (1) above, in which the total amount of the element A, the element B, and the element C contained in the active component is 40 mol% or more.

(3) A catalyst according to (1) or (2) above, in which the active component further contains an element E selected from the elements belonging to Group 6 of the periodic table.

(4) A catalyst according to any one of (1) to (3) above, wherein the active component further contains element F selected from the elements belonging to Group 2 of the periodic table.

(5) A catalyst according to any one of (1) to (4) above, wherein the active component further contains an element G selected from the elements belonging to Group 13 of the periodic table.

(6) A catalyst according to any one of (1) to (5) above, wherein the active component further contains an element H selected from the elements belonging to Group 10 of the periodic table.

(7) In the catalyst described in (1) above, the active component further includes an element E selected from the elements belonging to Group 6 of the periodic table, an element F selected from the elements belonging to Group 2 of the periodic table, and an element G selected from the elements belonging to Group 13 of the periodic table.

(8) In the catalyst described in (1) above, the active component further includes an element E selected from the elements belonging to Group 6 of the periodic table, an element F selected from the elements belonging to Group 2 of the periodic table, an element G selected from the elements belonging to Group 13 of the periodic table, and an element H selected from the elements belonging to Group 10 of the periodic table.

(9) The catalyst according to (1) above, wherein the active component further comprises an element F selected from the elements belonging to Group 2 of the periodic table, and an element G selected from the elements belonging to Group 13 of the periodic table.

(10) In the catalyst described in (1) above, the active component further includes an element E selected from the elements belonging to Group 6 of the periodic table, an element G selected from the elements belonging to Group 13 of the periodic table, and an element H selected from the elements belonging to Group 10 of the periodic table.

(11) In the catalyst described in (1) above, the active component further includes an element E selected from the elements belonging to Group 6 of the periodic table, an element F selected from the elements belonging to Group 2 of the periodic table, and an element H selected from the elements belonging to Group 10 of the periodic table.

(12) A method for directly producing butadiene by contacting ethanol with a catalyst, the catalyst having an active component exhibiting catalytic activity, the active component including element A selected from the elements belonging to Group 3 of the periodic table, element B selected from the elements belonging to Group 4 of the periodic table, element C selected from the elements belonging to Group 12 of the periodic table, and element D selected from the elements belonging to Groups 5 and 11 of the periodic table.
Of course, this is not the case.

As mentioned above, various embodiments of the present invention have been described, but these are presented as examples and do not limit the scope of the invention in any way. The novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. The embodiments and their modifications are included within the scope and gist of the invention, and are included in the scope of the invention and its equivalents set forth in the claims.

For example, the catalyst and butadiene production method of the present invention may have any other additional configurations compared to the above-mentioned embodiments, may be replaced with any configurations (steps) that exhibit similar functions, and some configurations (steps) may be omitted.

The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

1. Preparation of Catalyst First, a predetermined amount of each of the salts of the constituent elements was weighed out.
Next, the weighed chlorides of the constituent elements were dissolved in 5 mL of ethanol to prepare a solution.
Next, silica particles (average particle size: 2 μm, average pore diameter: 9 nm, total pore volume: 1.5 mL/g, specific surface area: 550 m ² /g) were added as a porous carrier to this solution, and the mixture was stirred at 50° C. for 2 hours.
Thereafter, the mixture was dried under reduced pressure at 70° C. for 4 hours.

Next, the weighed nitrates of the constituent elements were dissolved in 5 mL of water to prepare a solution.
Next, the sample that had been dried under reduced pressure for 4 hours was added to this solution, and the mixture was stirred at 50° C. for 2 hours.
Thereafter, the mixture was dried under reduced pressure at 90° C. for 4 hours, and then calcined at 400° C. for 3 hours.
In this manner, a catalyst in which the active component was supported on the carrier was obtained.
The ratio of elements constituting the active components of each of Catalysts 1 to 228 is as shown in Tables 3 to 12.

2. Evaluation of butadiene yield First, a cylindrical glass reaction tube was filled with the catalyst to a height of 2 cm to prepare a reaction bed.
Next, the temperature of the reaction bed was set to 400° C., the pressure of the reaction bed was set to 0.1 MPa, and a pretreatment was carried out by passing an oxygen-containing gas through the reaction tube.
Thereafter, the reaction temperature was set to a temperature of 300° C. or more and 400° C. or less, and a gas containing ethanol was supplied to the reaction tube.

The gas supplied to the reaction tube was a mixed gas in which ethanol was diluted with an inert gas. The ethanol concentration in the mixed gas was 9% by volume and 18% by volume, and the flow rate of the mixed gas was 2 mL/min. The mixed gas with the ethanol concentration adjusted to 18% by volume was used to evaluate the catalyst 226.
The gas flowing out from the reaction tube was collected and analyzed by a mass spectrometer to determine the ethanol conversion rate, butadiene selectivity, and butadiene yield.
The results are shown in Tables 3 to 12 below.
The evaluation examples of catalysts 1 to 94 correspond to Examples, the evaluation examples of catalysts 95, 128 and 226 correspond to Comparative Examples, and the other evaluation examples correspond to Reference Examples.

To confirm the effectiveness of the catalyst of the present invention, the results of evaluation examples of catalysts 1 to 3, 24, 27, 45, 62, 63, 95, 128 and 226 are summarized in Table 13 below.

As shown in Table 13, the catalyst of each Example had a high yield of butadiene. In contrast, the catalyst of each Comparative Example had a low yield of butadiene.
Among the Examples, the catalysts not containing a Group 5 element or a Group 11 element (element D) (Examples 7 and 8) tended to have a low yield of butadiene.
Furthermore, among the comparative examples, the catalyst not containing a Group 4 element (Comparative Example 3) showed an extremely low yield of butadiene, suggesting that the Group 4 element is an important element for catalytic activity.

Claims (12)

A catalyst used for producing butadiene directly from ethanol, comprising:
The catalyst has an active component that exhibits catalytic activity,
The active ingredient is
an element A selected from the elements of group 3 of the periodic table;
an element B selected from the elements of group 4 of the periodic table;
an element C selected from the elements belonging to group 12 of the periodic table;
and element D selected from the elements belonging to groups 5 and 11 of the periodic table. 2. The catalyst according to claim 1 ,
A catalyst, wherein the total amount of the element A, the element B and the element C contained in the active component is 40 mol % or more. 2. The catalyst according to claim 1 ,
A catalyst, wherein the active component further comprises an element E selected from the elements belonging to group 6 of the periodic table. 2. The catalyst according to claim 1 ,
A catalyst, wherein the active component further comprises an element F selected from the elements belonging to group 2 of the periodic table. 2. The catalyst according to claim 1 ,
A catalyst, wherein the active component further comprises an element G selected from the elements belonging to group 13 of the periodic table. 2. The catalyst according to claim 1 ,
A catalyst, wherein the active component further comprises an element H selected from the elements belonging to group 10 of the periodic table. 2. The catalyst according to claim 1 ,
The catalyst, wherein the active component further comprises an element E selected from the elements belonging to Group 6 of the periodic table, an element F selected from the elements belonging to Group 2 of the periodic table, and an element G selected from the elements belonging to Group 13 of the periodic table. 2. The catalyst according to claim 1 ,
The catalyst, wherein the active component further comprises an element E selected from the elements belonging to Group 6 of the periodic table, an element F selected from the elements belonging to Group 2 of the periodic table, an element G selected from the elements belonging to Group 13 of the periodic table, and an element H selected from the elements belonging to Group 10 of the periodic table. 2. The catalyst according to claim 1 ,
The catalyst, wherein the active component further comprises an element F selected from the elements belonging to Group 2 of the Periodic Table, and an element G selected from the elements belonging to Group 13 of the Periodic Table. 2. The catalyst according to claim 1 ,
The catalyst, wherein the active component further comprises an element E selected from the elements belonging to Group 6 of the periodic table, an element G selected from the elements belonging to Group 13 of the periodic table, and an element H selected from the elements belonging to Group 10 of the periodic table. 2. The catalyst according to claim 1 ,
The catalyst, wherein the active component further comprises an element E selected from the elements belonging to Group 6 of the periodic table, an element F selected from the elements belonging to Group 2 of the periodic table, and an element H selected from the elements belonging to Group 10 of the periodic table. A process for directly producing butadiene by contacting ethanol with a catalyst, comprising the steps of:
The catalyst has an active component that exhibits catalytic activity,
The active ingredient is
an element A selected from the elements of group 3 of the periodic table;
an element B selected from the elements of group 4 of the periodic table;
an element C selected from the elements belonging to group 12 of the periodic table;
and element D selected from the elements belonging to groups 5 and 11 of the periodic table.