JP6085780B2 - Method for preparing catalyst for olefin production and method for producing olefin - Google Patents

Description

  The present invention relates to a preparation method of an olefin production catalyst, an olefin production catalyst, and an olefin production method for producing an olefin having one or more carbon atoms of the alcohol as a raw material.

  The current main process for producing olefins, which are various chemical raw materials, is the pyrolysis of petroleum fractions. However, in recent years, in the field of manufacturing chemical raw materials, it is required to convert chemical raw materials from petroleum-based resources to non-edible biomass resources in preparation for the suppression of carbon dioxide generation and future rise or depletion of petroleum resources. Yes. In particular, there is a demand for a technique for more efficiently producing polypropylene, which is a typical general-purpose resin, from bioethanol, which is a biomass resource.

  In Patent Document 1, an acid catalyst, particularly zeolite, is used as a method for producing olefin from ethanol. However, when an acid catalyst is used, the dehydration reaction of ethanol is accompanied and there is a problem that propylene selectivity is low because a large amount of ethylene is produced.

  Non-Patent Document 1, Non-Patent Document 2 and Patent Document 2 report that propylene can be obtained from ethanol using indium oxide as a catalyst. Various methods for producing indium oxide powder have been known for a long time, and all are for obtaining a high-density sintered body as ITO (Indium-Tin-Oxide) for electronic materials (for example, (See Patent Documents 3 to 6).

JP 2007-290991 A JP 2013-6831 A JP-A-5-193939 JP 2003-277052 A JP 2006-264989 A JP 2006-306669 A

Masakazu Iwamoto et. al. , “Selective conversion of ethanol to proposal on In 2 O 3 -based catalyst”, Europac X, PM 149 (2011) Masakazu Iwamoto et al., “Selective Conversion of Ethanol to Propylene with In 2 O 3 Catalyst”, 108th Catalysis Conference, 2F04 (2011)

The present inventors have found that indium oxide is effective as a catalyst for producing an olefin having at least one carbon atom larger than the number of carbon atoms of the alcohol. However, the indium oxide catalyst still has room for improvement in terms of catalyst activity and catalyst life.
Patent Document 2 discloses an olefin production method for producing an olefin having 1 or more carbon atoms from an alcohol in the presence of an indium oxide-containing catalyst. As a catalyst preparation method in the literature, a salt containing a metal component (nitrate, sulfate, chloride, etc.) is baked as it is in air, or a base such as ammonia water is dropped into an aqueous solution containing the metal component. Although a method of forming a precipitate and baking after filtration is mentioned, a method for preparing a catalyst having a higher propylene yield and a longer life has been demanded.

  The present invention has been made in view of the above-mentioned problems, and the object thereof is to stably produce an olefin having at least one carbon atom larger than the alcohol for a long time with a high yield using the alcohol as a raw material. An object of the present invention is to provide a method for preparing a catalyst for olefin production having high performance and long life, a catalyst for olefin production, and a method for producing olefin.

As a result of intensive studies to solve the above problems, the present inventors have added a base aqueous solution and a quaternary ammonium salt aqueous solution of the formula (I) to an aqueous solution containing an indium salt, whereby A long-life catalyst capable of producing an olefin having at least one carbon atom larger than the number of carbon atoms, particularly an olefin having one carbon atom larger than that of the raw alcohol, in a high yield is obtained. As a result, the present invention has been completed.
That is, the present invention is as follows.

[1] A method for preparing a catalyst for producing an olefin having at least one carbon atom greater than the number of carbon atoms of the alcohol from an alcohol, comprising an aqueous solution containing an indium salt, an aqueous base solution, and a compound of formula (I) A method for preparing a catalyst for olefin production, comprising forming a precipitate by adding an aqueous quaternary ammonium salt solution, and aging the suspension to collect, wash, and calcine the precipitate.
(R _{1 to} R ₄ are alkyl groups, X ⁻ represents an anion)
[2] Each of R _{1 to} R ₄ in formula (I) is any of an ethyl group, a propyl group, and a butyl group, and X ^{− in} formula (I) is a hydroxide ion (OH ⁻ ), The method for preparing a catalyst for olefin production according to the above [1], which is either bromide ion (Br ⁻ ) or chloride ion (Cl ⁻ ).
[3] The method for preparing a catalyst for olefin production according to the above [1] or [2], wherein R _{1 to} R _{4 in the} formula (I) are all propyl groups.
[4] An aqueous base solution is added so that the pH is 5 to 10, and then an aqueous quaternary ammonium salt of the formula (I) is added so that the pH is 9 or more. The preparation method of the catalyst for olefin manufacture in any one.
[5] The method for preparing a catalyst for olefin production according to any one of [1] to [4], wherein the alcohol is ethanol and the olefin is propylene.
[6] An olefin production catalyst prepared by the preparation method according to any one of [1] to [5].
[7] A method for producing an olefin, wherein an olefin having at least one carbon atom larger than the number of carbon atoms of the alcohol is produced by bringing the alcohol into contact with the olefin production catalyst according to [6].

According to the present invention, an olefin having at least one carbon atom larger than the alcohol, particularly an olefin having one carbon atom larger than the carbon number of the raw alcohol, is stable for a long time with a high yield. Thus, it is possible to provide a method for preparing a long-lived olefin production catalyst that can be produced in the same manner.
It is inferred that such an olefin production catalyst is formed by the addition of a quaternary ammonium salt that forms a skeleton of indium hydroxide having a structure in which the indium oxide after calcination is difficult to be reduced to metal indium. Is done.

  Although the preparation method of the catalyst for olefin production of this invention is demonstrated, this invention is not limited to the following description. In the present specification, when a numerical range is indicated by the expression “to”, it includes a lower limit value and an upper limit value.

[1. Preparation method of catalyst for olefin production]
The method for preparing an olefin production catalyst of the present invention comprises a precipitation generating step of adding an aqueous base solution and an aqueous quaternary ammonium salt of formula (I) to an aqueous solution containing an indium salt to form a precipitate of indium hydroxide. Thereafter, the precipitate obtained through an aging step for aging the suspension is filtered, recovered, washed, and calcined, so that the olefin having at least one carbon atom larger than the alcohol, particularly the starting alcohol, is used as the starting material. Thus, an olefin production catalyst composed of high performance and long life indium oxide capable of stably producing an olefin having one carbon atom larger than the number of carbon atoms in a high yield for a long time is obtained.
Hereinafter, the details of the catalyst preparation method of the present invention will be described.

(Precipitation generation process)
Examples of the indium salt include indium nitrate, indium sulfate, indium chloride, and indium acetate. Of these, indium nitrate is preferably used. The indium concentration in the aqueous solution containing the indium salt is preferably 0.1 mol / L or more.

  The “first precipitant” mixed with an aqueous solution containing an indium salt is an aqueous base solution, and examples of the base include ammonia, sodium hydroxide, potassium hydroxide, magnesium hydroxide, urea, and the like. Used as an aqueous solution. Among these, it is preferable to use ammonia water.

A specific compound contained in the “second precipitant” mixed with an aqueous solution containing an indium salt is a quaternary ammonium salt of formula (I) and is used as an aqueous solution.
R _{1 to} R _{4 in} formula (I) are alkyl groups, and the alkyl group is preferably any of an ethyl group, a propyl group, and a butyl group, and all of R _{1 to} R ₄ are propyl groups. Is more preferable.
X < ^- > in formula (I) is an anion, and examples of the anion include hydroxide ion, fluoride ion, chloride ion, bromide ion, iodide ion, nitrate ion, nitrite ion, hydrogen carbonate ion, and alumina. Inorganic anions such as acid ions, organic carboxylate ions such as formate ion and acetate ion, organic sulfonate ions such as methanesulfonate ion and toluenesulfonate ion, organic anions such as phenoxide ion, etc. Oxide ions, bromide ions, and chloride ions are preferable, and hydroxide ions are more preferable.
Specifically, the quaternary ammonium salt of the formula <I> is preferably tetraethylammonium hydroxide (TEAOH), tetrapropylammonium hydroxide (TPAOH), tetrabutylammonium hydroxide (TBAOH), and particularly preferably TPAOH.

The first precipitating agent and the second precipitating agent may be used together, but it is preferable to add the second precipitating agent after adjusting the pH by adding a certain amount of the first precipitating agent.
In that case, the pH of the mixed solution after adding the first precipitant is preferably 5 to 10, more preferably 6 to 9. The pH after adding the second precipitating agent is preferably 9 or more, and more preferably 11 or more.

  In addition, although stirring is performed when the precipitant is added, it is preferable to stir the mixed solution so that the precipitated particles in the aqueous solution do not settle, aggregate, and solidify. Further, the rate of addition of the precipitating agent is preferably 10 mL / min or more, although it depends on the concentration of the indium salt and the precipitating agent.

(Aging process)
After the first and second precipitants are added to form a precipitate and then the precipitate is aged in the mixed solution before being collected by filtration, the intended high performance catalyst can be easily obtained.
Here, “aging” refers to an operation of stirring the mixed solution at a predetermined temperature for a predetermined time. A preferable aging temperature is 10 ° C. to 100 ° C., more preferably 20 ° C. to 80 ° C., and a preferable aging time is 1 hour or more, more preferably 10 hours or more. The stirring speed is preferably such that the mixed solution is stirred so that the precipitated particles do not settle, aggregate or solidify.

The mixed solution containing the precipitate obtained through the aging step is filtered to collect the precipitate, which is washed, dried and calcined, whereby the target catalyst for olefin production of the present invention can be obtained. Here, a calcination temperature is 500 degreeC-1000 degreeC, Preferably it is 600 degreeC-800 degreeC, More preferably, it is 650 degreeC-750 degreeC.
When the catalyst is in a powder form, it is appropriately pulverized and sized so as to be in a desired particle size range. Moreover, when it is a pellet form, it grind | pulverizes suitably and shape | molds, for example in a column shape by a well-known means.

[2. Olefin production catalyst)
The catalyst for olefin production of the present invention is prepared by the above-described method for preparing the catalyst for olefin production of the present invention, and contains indium oxide. Examples of the form of the catalyst include forms of indium oxide powder and pellets made of indium oxide.

Here, as a preferable example of indium oxide include indium oxide (In ₂ O _3). Examples of the type of indium oxide include cubic or amorphous. Moreover, as long as the effect of this invention is not inhibited, you may contain a various other metal component.

[3. (Olefin production method)
The olefin production method using the olefin production catalyst of the present invention includes a production step of producing an olefin having at least one carbon atom larger than the number of carbon atoms of the alcohol from an alcohol, What is necessary is just to make alcohol and the catalyst for olefin manufacture of this invention contact by reaction temperature 300 to 700 degreeC.

Although it does not specifically limit as alcohol made to react with the catalyst which concerns on this invention, It is preferable that it is a C2-C12 primary alcohol. Examples of the primary alcohol having 2 to 12 carbon atoms include ethanol, 1-propanol, 1-butanol, isobutanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1- Examples include decanol, 1-undecanol, 1-dodecanol and the like.
Among these, as the alcohol, a primary alcohol having 2 to 8 carbon atoms is preferable, and a primary alcohol having 2 to 4 carbon atoms is more preferable. If the alcohol is in this range, the selectivity of the olefin having at least one carbon atom larger than that of the raw material alcohol in the product can be improved.

  Furthermore, as the alcohol used in the present invention, it is more preferable to use a bioresource-derived (biomass) alcohol (bioalcohol). Unlike alcohol obtained from fossil fuel, by reacting biological resource-derived alcohol with the catalyst for olefin production of the present invention, at least one carbon atom number of raw material alcohol is increased without increasing carbon dioxide in the environment. Large olefins can be produced.

  The olefin having at least one carbon atom larger than the number of carbon atoms of the raw material alcohol to be produced is 2n-1, 2n, 3n- when the raw material alcohol has n carbon atoms (n is 2 or more). An olefin having 1 carbon number or the like. Specifically, when the alcohol as a raw material is ethyl alcohol, in addition to ethylene, the alcohol as the raw material such as propylene, 1-butene, cis 2-butene, trans 2-butene, isobutene, and pentene is 1- In the case of propanol, pentenes, hexenes, octenes and the like are produced in addition to propylene.

  The reaction temperature in the olefin production step is preferably 300 ° C to 700 ° C, and more preferably 350 ° C to 600 ° C. By carrying out the reaction at a temperature in this range, it is possible to prevent the selectivity of the olefin having at least one carbon atom larger than the carbon atom number of the raw material alcohol in the product from decreasing.

  In the olefin production step, the method for contacting the raw alcohol with the catalyst for olefin production of the present invention is not particularly limited, but the raw alcohol may be simply introduced into a container filled with the catalyst. Examples of the reactor include a fixed bed reactor, a fluidized bed reactor, a batch reactor, a semi-batch reactor and the like. From the viewpoint of olefin productivity, a fixed bed reactor or a fluidized bed reactor. A reactor is preferred, and a fixed bed reactor is more preferred.

  Although the shape of the alcohol used as a raw material is not particularly limited, it is preferably a gas from the viewpoint of enhancing the production efficiency of olefin and facilitating the reaction. Moreover, when contacting gaseous alcohol with a catalyst in a container, you may supply alcohol in a container combining with another component. Other components include, for example, nitrogen gas, water vapor, hydrogen, carbon monoxide, carbon dioxide, all or part of the product recovered from the reactor outlet, the raw alcohol, and the reactivity with the generated olefin. An inert carrier gas or the like which is not necessary can be exemplified. From the viewpoint of stabilizing the catalyst activity, it is preferable that water vapor, hydrogen, and nitrogen coexist among the other components.

  Although the usage-amount of the catalyst for olefin production of this invention is not specifically limited, It is preferable that it is 0.000002 ton-0.02 ton per 1 ton of alcohol. Moreover, the supply speed | rate of alcohol should just be 0.002 ton / h-200 ton / h per ton of catalyst, for example, and it is more preferable that it is 0.02 ton / h-20 ton / h.

  The contact time between the alcohol and the catalyst for olefin production is not particularly limited, and is, for example, 0.001 second to 1 hour, preferably 0.1 second to 1 minute.

  The selection yield of the olefin having at least one carbon atom larger than that of the alcohol as the raw material is not particularly limited, but it is 35% or more at the initial stage (reaction elapsed time: about 2 hours). Is preferable, 40% or more is more preferable, and 45% or more is more preferable. Here, the selective yield of olefin is (the number of carbon moles of the olefin having at least one carbon atom larger than the number of carbon atoms of the raw material alcohol) / (number of carbon moles of the alcohol subjected to the reaction) × 100 (%).

  In addition, as a manufacturing method of the olefin of this invention, it is preferable that raw material alcohol is ethanol and an olefin of carbon number at least 1 larger than the carbon atom number of raw material alcohol is a propylene.

  Hereinafter, embodiments of the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples, and it goes without saying that various aspects are possible in detail. Absent.

[Example 1]
21.11 g of indium nitrate n-hydrate (In (NO ₃ ) ₃ · nH ₂ O, manufactured by Kanto Chemical Co., Ltd., product number 20298-08, purity 99.9% or more) as an indium source, 500.30 g of deionized water A liquid A was prepared by mixing.
Moreover, 9.15 g of ammonia water (manufactured by Kanto Chemical Co., Ltd., special grade 28-30%) as a first precipitant was mixed with 233.70 g of deionized water to prepare a liquid B.
Then, 330.75 g of tetrapropylammonium hydroxide (TPAOH) aqueous solution (manufactured by Tokyo Chemical Industry Co., Ltd., product number T0964, concentration 10%) was used as the second precipitating agent to prepare C solution.

  While stirring the liquid A at room temperature (25 ° C.), the liquid B was added with a burette at a rate of 5 drops / second over about 20 minutes. The pH of the solution after dropping was 7.3. Subsequently, solution C was added at a rate of 5 drops / second. The pH after addition of solution C was 11.99.

  This suspension was aged by stirring at room temperature (25 ° C.) for 40 hours. After aging, the resulting white precipitate was collected by filtration, washed with 500 ml of ion-exchanged water for 3 minutes and then filtered three times. The obtained solid was dried at 80 ° C. overnight to obtain an unfired sample.

This sample was spread thinly on a magnetic dish, heated to 700 ° C. at 1 ° C./min, and calcined in air for 5 hours to obtain an indium oxide catalyst.
The specific surface area of this catalyst was 7.1 m ² / g. The specific surface area was measured by a nitrogen adsorption method using a commercially available apparatus (BELSORPmax, manufactured by Nippon Bell Co., Ltd.) (for nitrogen adsorption method, Yoshio Ono, Isao Suzuki, “Science and Application of Adsorption”, Kodansha Scientific) Fick, page 60 (2003)).

[Example 2]
A solution A was prepared in the same manner as in Example 1 except that 21.63 g of indium nitrate n hydrate and 501.41 g of deionized water were used.
Further, a liquid B was prepared in the same manner as in Example 1 except that 9.16 g of ammonia water and 231.03 g of deionized water were used.
Then, 238.15 g of an aqueous tetraethylammonium hydroxide (TEAOH) solution (manufactured by Tokyo Chemical Industry Co., Ltd., product number T0096, concentration 10%) was used as the second precipitating agent, and the resulting liquid C was obtained.

  While stirring the liquid A at room temperature (25 ° C.), the liquid B was added with a burette at a rate of 5 drops / second over about 20 minutes. The pH of the solution after dropping was 7.3. Subsequently, solution C was added at a rate of 5 drops / second. The pH after addition of solution C was 12.07.

  This suspension was aged by stirring at room temperature (25 ° C.) for 40 hours. After aging, the resulting white precipitate was collected by filtration, washed with 500 ml of ion-exchanged water for 3 minutes and then filtered three times. The obtained solid was dried at 80 ° C. overnight to obtain an unfired sample.

This sample was spread thinly on a magnetic dish, heated to 700 ° C. at 1 ° C./min, and calcined in air for 5 hours to obtain an indium oxide catalyst.
The surface area of this catalyst was 10.7 m ² / g.

Example 3
A solution A was prepared in the same manner as in Example 1 except that 21.23 g of indium nitrate n hydrate and 500.90 g of deionized water were used.
A liquid B was prepared in the same manner as in Example 1 except that the ammonia water was 8.77 g and the deionized water was 222.80 g.
Then, 402.04 g of an aqueous solution of tetrabutylammonium hydroxide (TBAOH) (manufactured by Tokyo Chemical Industry Co., Ltd., product number T0096, concentration 10%) was used as the second precipitating agent to prepare C solution.

  While stirring the liquid A at room temperature (25 ° C.), the liquid B was added with a burette at a rate of 5 drops / second over about 20 minutes. The pH of the solution after dropping was 7.3. Subsequently, solution C was added at a rate of 5 drops / second. The pH after adding solution C was 12.42.

  This suspension was aged by stirring at room temperature (25 ° C.) for 40 hours. After aging, the resulting white precipitate was collected by filtration, washed with 500 ml of ion-exchanged water for 3 minutes and then filtered three times. The obtained solid was dried at 80 ° C. overnight to obtain an unfired sample.

This sample was spread thinly on a magnetic dish, heated to 700 ° C. at 1 ° C./min, and calcined in air for 5 hours to obtain an indium oxide catalyst.
The surface area of this catalyst was 12.8 m ² / g.

Example 4
A solution A was prepared in the same manner as in Example 1 except that 21.37 g of indium nitrate n hydrate and 499.61 g of deionized water were used.
Further, a liquid B was prepared in the same manner as in Example 1 except that the ammonia water was 8.89 g and the deionized water was 222.39 g.
Then, 306.1 g of tetrapropylammonium hydroxide (TPAOH) aqueous solution was used to prepare a C solution.

  While stirring the liquid A at room temperature (25 ° C.), the liquid B was added with a burette at a rate of 5 drops / second over about 20 minutes. The pH of the solution after dropping was 7.3. Subsequently, solution C was added at a rate of 5 drops / second. The pH after addition of solution C was 11.26.

  This suspension was aged by stirring at 50 ° C. for 40 hours. After aging, the resulting white precipitate was collected by filtration, washed with 500 ml of ion-exchanged water for 3 minutes and then filtered three times. The obtained solid was dried at 80 ° C. overnight to obtain an unfired sample.

This sample was spread thinly on a magnetic dish, heated to 700 ° C. at 1 ° C./min, and then calcined in air for 5 hours to obtain an indium oxide catalyst (Catalyst No. N700-50 ° C.).
The surface area of this catalyst was 10.6 m ² / g.

Example 5
A solution A was prepared in the same manner as in Example 1 except that 21.67 g of indium nitrate n hydrate and 500.54 g of deionized water were used.
Further, a liquid B was prepared in the same manner as in Example 1 except that the ammonia water was 8.98 g and the deionized water was 311.34 g.
Then, 317.8 g of an aqueous tetrapropylammonium hydroxide (TPAOH) solution was used to prepare a C solution.

  While stirring the liquid A at room temperature (25 ° C.), the liquid B was added with a burette at a rate of 5 drops / second over about 20 minutes. The pH of the solution after dropping was 7.3. Subsequently, solution C was added at a rate of 5 drops / second. The pH after addition of solution C was 11.31.

  This suspension was aged by stirring at 80 ° C. for 40 hours. After aging, the resulting white precipitate was collected by filtration, and the operation of stirring in 500 ml of ion exchange water for 3 minutes and then filtering was repeated 3 times. The obtained solid was dried at 80 ° C. overnight to obtain an unfired sample.

This sample was spread thinly on a magnetic dish, heated to 700 ° C. at 1 ° C./min, and calcined in air for 5 hours to obtain an indium oxide catalyst.
The surface area of this catalyst was 10.6 m ² / g.

[Comparative Example 1]
A solution A was prepared in the same manner as in Example 1 except that 21.33 g of indium nitrate n hydrate and 500.37 g of deionized water were used.
Further, a liquid B was prepared in the same manner as in Example 1 except that the ammonia water was 8.84 g and the deionized water was 217.88 g.
Then, 261.65 g of a benzyltrimethylammonium hydroxide (BTMAOH) aqueous solution (manufactured by Tokyo Chemical Industry Co., Ltd., product number B1070, concentration 10%) was used as the second precipitating agent to prepare C solution.

  While stirring the liquid A at room temperature (25 ° C.), the liquid B was added with a burette at a rate of 5 drops / second over about 20 minutes. The pH of the solution after dropping was 7.3. Subsequently, solution C was added at a rate of 5 drops / second. The pH after addition of solution C was 12.18.

  This suspension was aged by stirring at room temperature (25 ° C.) for 40 hours. After aging, the resulting white precipitate was collected by filtration, and the operation of stirring in 500 ml of ion exchange water for 3 minutes and then filtering was repeated 3 times. The obtained solid was dried at 80 ° C. overnight to obtain an unfired sample.

This sample was spread thinly on a magnetic dish, heated to 700 ° C. at 1 ° C./min, and calcined in air for 5 hours to obtain an indium oxide catalyst.
The surface area of this catalyst was 11.6 m ² / g.

[Comparative Example 2]
A solution A was prepared in the same manner as in Example 1 except that 12.46 g of indium nitrate n hydrate and 500.20 g of deionized water were used.
Further, a liquid B was prepared in the same manner as in Example 1 except that the ammonia water was 9.20 g and the deionized water was 230.10 g.
Then, 10.08 g of ethanolamine (EA) (manufactured by Tokyo Chemical Industry Co., Ltd., product number A0297, concentration of 99% or more) was used as the second precipitating agent to prepare a C solution.

  While stirring the liquid A at room temperature (25 ° C.), the liquid B was added with a burette at a rate of 5 drops / second over about 20 minutes. The pH of the solution after dropping was 7.3. Subsequently, solution C was added at a rate of 5 drops / second. The pH after addition of solution C was 9.65.

  This suspension was aged by stirring at room temperature (25 ° C.) for 40 hours. After aging, the resulting white precipitate was collected by filtration, washed with 500 ml of ion-exchanged water for 3 minutes and then filtered three times. The obtained solid was dried at 80 ° C. overnight to obtain an unfired sample.

This sample was spread thinly on a magnetic dish, heated to 700 ° C. at 1 ° C./min, and calcined in air for 5 hours to obtain an indium oxide catalyst.
The surface area of this catalyst was 17.3 m ² / g.

[Comparative Example 3]
A solution A was prepared in the same manner as in Example 1 except that 21.16 g of indium nitrate n hydrate and 500.39 g of deionized water were used.
Further, as a precipitating agent, liquid B was prepared by mixing 23.21 g of ammonia water (special grade 28-30% manufactured by Kanto Chemical Co., Ltd.) and 311.15 g of deionized water.

While stirring the liquid A at room temperature (25 ° C.), the liquid B was added with a burette at a rate of 5 drops / second over about 20 minutes. This suspension was aged by stirring at room temperature (25 ° C.) for 40 hours. The pH immediately after the liquid B was added was 8.55, and the final pH of the suspension after aging for 40 hours was 8.45.
After aging, the resulting white precipitate was collected by filtration, washed with 500 ml of ion-exchanged water for 3 minutes and then filtered three times. The obtained solid was dried at 80 ° C. overnight to obtain an unfired sample.

This sample was spread thinly on a magnetic dish, heated to 700 ° C. at 1 ° C./min, and calcined in air for 5 hours to obtain an indium oxide catalyst.
The surface area of this catalyst was 31.7 m ² / g.

[Reaction of ethanol]
Using the catalysts prepared in Examples 1 to 3 and Comparative Examples 1 and 2, ethanol was reacted.
Each catalyst (0.5 g) was filled in a quartz reaction tube, and the temperature of the catalyst filling portion was maintained at 550 ° C. Ethanol and water vapor for dilution (H ₂ O), hydrogen (H ₂ ), and nitrogen (N ₂ ) so that their partial pressures are 0.3, 0.08, 0.3, and 0.32, respectively. After mixing, the total gas flow rate was 12.8 ml / min (25 ° C., converted to 1 atm) and supplied to the reaction tube.

  After starting the supply of the reaction raw materials, the gas at the outlet of the reaction tube was analyzed with a gas chromatograph device every predetermined time, and the propylene yield was measured. In addition, the propylene yield was calculated in terms of carbon yield by the following formula.

Propylene yield (%) = [(Amount of propylene in product gas (mol / min) × 3)
/ (Ethanol supply amount (mol / min) × 2)] × 100

  Table 1 shows the propylene yield when each catalyst was used.

  As shown in the results of Table 1, in Examples 1 to 5, a high propylene yield was obtained for a long time. On the other hand, as in Comparative Examples 1 to 3, in the catalyst prepared by a method that does not use the second precipitant containing the compound of formula <I), the propylene yield rapidly decreased after a longer reaction. .

Claims (6)

A process for preparing a catalyst for producing an olefin having at least one carbon atom greater than the number of carbon atoms of the alcohol from an alcohol, comprising:
A precipitate is formed by adding an aqueous base solution and an aqueous quaternary ammonium salt of formula (I) to an aqueous solution containing an indium salt;
The precipitate obtained by aging the suspension is filtered, washed, and calcined.
A method for preparing a catalyst for olefin production.

(R _{1 to} R ₄ are alkyl groups, and X ⁻ represents an anion) Each of R _{1 to} R ₄ in formula (I) is any one of an ethyl group, a propyl group, and a butyl group, and X ^{− in} formula (I) is a hydroxide ion (OH ⁻ ), a bromide ion ( The method for preparing a catalyst for olefin production according to claim 1, which is any one of Br ⁻ ) and chloride ions (Cl ⁻ ). The method for preparing a catalyst for olefin production according to claim 1 or 2, wherein R _{1 to} R _{4 in} formula (I) are all propyl groups.   The olefin according to any one of claims 1 to 3, wherein an aqueous base solution is added so that the pH is 5 to 10, and then an aqueous quaternary ammonium salt of the formula (I) is added so that the pH is 9 or more. A method for preparing a catalyst for production.   The method for preparing a catalyst for olefin production according to any one of claims 1 to 4, wherein the alcohol is ethanol and the olefin is propylene. An olefin for producing an olefin having at least one carbon atom greater than the number of carbon atoms of the alcohol by contacting the alcohol with the catalyst for olefin production prepared by the preparation method according to any one of claims 1 to 5 . Production method.