JP2013193977A - Method for producing methyl acetylene - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of producing methyl acetylene at an excellent yield.SOLUTION: In this method for producing methyl acetylene, propadiene in a mixture including propadiene and a halogenated aliphatic hydrocarbon is isomerized in the presence of a catalyst formed by carrying an alkali metal compound on alumina. In the method for producing methyl acetylene, a use amount of the catalyst is ≥3.0 moles in terms of an alkali metal element included in the catalyst, with respect to the 1 mol halogenated aliphatic hydrocarbon.

Description

  The present invention relates to a method for producing methylacetylene by isomerizing propadiene.

  As a method for isomerizing propadiene to methylacetylene, Patent Document 1 describes a method for producing methylacetylene by reacting propadiene in the presence of a catalyst in which potassium carbonate is supported on γ-alumina. .

Examples of propadiene include olefins produced by thermal decomposition of naphtha (steam cracking method) that are obtained as by-products with ethylene and propylene, and halogenated propane or halogenated propene in the presence or absence of a catalyst. Those obtained by dehydrohalogenation are known (see, for example, Patent Documents 2 to 4 and Non-Patent Documents 1 and 2).
Here, if the propadiene contains a halogenated aliphatic hydrocarbon as an impurity, methylacetylene may not be obtained in a satisfactory yield.

JP-A-2-290831 East German Patent Application No. 240740 East German Patent Application No. 240741 Japanese Examined Patent Publication No. 61-37254

Kirk-Othmer Encyclopedia of Chemical Technology, 2nd edition, p.547-556 BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, Vol.44, 1971, p.1388-1393

  The subject of this invention is providing the method which can manufacture a methylacetylene with a favorable yield.

As a result of intensive studies to solve the above problems, the present inventor has found a solution means having the following configuration, and has completed the present invention.
(1) A process for producing methylacetylene, wherein the propadiene in a mixture containing propadiene and a halogenated aliphatic hydrocarbon is isomerized in the presence of a catalyst in which an alkali metal compound is supported on alumina, The method for producing methylacetylene, wherein the amount used is 3.0 mol or more in terms of an alkali metal element contained in the catalyst with respect to 1 mol of the halogenated aliphatic hydrocarbon.
(2) The production method according to (1), wherein the mixture is obtained by a dehydrohalogenation reaction of a halogenated propane and / or a halogenated propene.
(3) The halogenated aliphatic hydrocarbon is at least selected from the group consisting of 1-chloro-1-propene, 2-chloro-1-propene, 3-chloro-1-propene, 1-chloropropane and 2-chloropropane. The production method according to (1) or (2), which is one type.
(4) The production method according to any one of (1) to (3), wherein the alumina is γ-alumina having an average pore radius of 4.5 nm or more.
(5) The production method according to any one of (1) to (4), wherein the alumina is γ-alumina having a pore volume of 0.40 mL / g or more.
(6) The production method according to any one of (1) to (5), wherein the alkali metal compound is a potassium compound.
(7) The production method according to any one of (1) to (6), wherein the catalyst is obtained by subjecting alumina to a contact treatment with a solution containing an alkali metal compound and then firing.

  According to the present invention, even if propadiene contains a halogenated aliphatic hydrocarbon as an impurity, there is an effect that methylacetylene can be produced in a good yield.

  In the method for producing methylacetylene according to the present invention, a catalyst in which an alkali metal compound is supported on alumina as a carrier is used. Examples of alumina include γ-alumina, α-alumina, θ-alumina and the like, and among the exemplified aluminas, γ-alumina is preferable.

  The alumina is preferably γ-alumina having an average pore radius of 4.5 nm or more, and more preferably γ-alumina having an average pore radius of 5.0 nm or more. Thereby, a methylacetylene can be manufactured with a favorable yield. The reason for this is that when the average pore radius is 4.5 nm or more, the pore volume is increased moderately, and reactants and products in the pores, that is, propadiene and methylacetylene are easily diffused, and the reaction rate It is inferred that this is due to the improvement. The upper limit of the average pore radius of γ-alumina is preferably 15 nm or less, and more preferably 10 nm or less. The average pore radius of γ-alumina is a value obtained by measurement by mercury porosimetry.

  The alumina is preferably γ-alumina having a pore volume of 0.40 mL / g or more, and more preferably γ-alumina having a pore volume of 0.50 mL / g or more. Thereby, a methylacetylene can be manufactured with a favorable yield. The reason for this is presumed to be the same as explained for the average pore radius. The upper limit of the pore volume of γ-alumina is preferably 2.5 mL / g or less, and more preferably 1.5 mL / g or less. The pore volume of γ-alumina is a value obtained by measurement by mercury porosimetry.

The specific surface area of alumina is preferably 100 m ² / g or more from the viewpoint of the amount of alkali metal compound supported. The specific surface area is a value obtained by measurement by a nitrogen adsorption method (BET method), and is usually a value obtained by measurement by a BET one-point method.

  Alumina may be heat-treated before supporting the alkali metal compound from the viewpoint of removing impurities adhering to the surface and activating the surface. The heat treatment can be performed in an oxidizing gas or inert gas atmosphere, and can be performed in multiple stages by combining these gas atmospheres. An oxidizing gas means a gas containing an oxidizing substance. Examples of the oxidizing gas include air and oxygen-containing gas such as pure oxygen. Examples of the inert gas include nitrogen gas, helium gas, and argon gas. As examples of the gas used during the heat treatment, nitrogen gas, oxygen gas, air, or a mixed gas of nitrogen gas and oxygen gas is preferable.

  The heat treatment temperature is preferably 100 to 600 ° C. The heat treatment time is preferably 1 to 48 hours, and more preferably 2 to 24 hours.

  Examples of the alkali metal compounds supported on alumina include alkali metal oxides, alkali metal halides, alkali metal hydroxides, alkali metal carbonates, alkali metal nitrates, and alkali metal hydrides. , Alkali metal alkoxides, alkali metal acetates, and the like, and two or more of them may be supported on alumina as necessary. Of the alkali metal compounds exemplified, potassium compounds are preferred.

  The supported amount of alkali metal in the catalyst is preferably 0.01 to 6.7 mmol, more preferably 0.15 to 4.0 mmol, per 1 g of the catalyst. The amount of alkali metal supported can be quantified by, for example, inductively coupled plasma emission spectroscopy (hereinafter referred to as “ICP analysis”).

  The catalyst is preferably used as a molded body, and the shape thereof is, for example, a spherical granular shape (spherical), a cylindrical shape, a pellet shape, an extruded shape, a ring shape, a honeycomb shape, or an appropriately sized granule that is pulverized and classified after molding. And the like. When the catalyst is pulverized and classified into a granule of an appropriate size after molding, the surface area of the catalyst increases and the contact area with propadiene also increases, making it easy to isomerize propadiene and increasing the yield of methylacetylene. Can be improved.

  Examples of a method for supporting an alkali metal compound on alumina include a method in which alumina is contact-treated with a solution containing an alkali metal compound, a coprecipitation method, and the like. In the contact treatment, the treatment temperature is usually 0 to 100 ° C., preferably 0 to 50 ° C., and the treatment pressure is usually 0.1 to 1 MPa, preferably atmospheric pressure. . The contact treatment can be performed in an air atmosphere or an inert gas atmosphere such as nitrogen gas, helium gas, argon gas, carbon dioxide, or the like. These atmospheres may contain water vapor. Specific examples of the contact treatment include impregnation, immersion, kneading and the like, and water is preferable as a solvent used for preparing the solution.

  The catalyst is preferably calcined after an alkali metal compound is supported on alumina. Thereby, the supported alkali metal compound (however, excluding the alkali metal oxide) can be converted into an alkali metal oxide. In the case of performing the firing, as the alkali metal compound used for loading, it is preferable to use a thermally decomposable salt such as carbonate, nitrate, acetate, hydroxide, halide, etc. Is preferred.

  Firing can be performed in an oxidizing gas, reducing gas, or inert gas atmosphere, and these gas atmospheres can be combined and performed in multiple stages. Examples of the oxidizing gas and the inert gas include the same gases as exemplified in the heat treatment of alumina described above. A reducing gas means a gas containing a reducing substance. Examples of the reducing gas include a hydrogen-containing gas, a carbon monoxide-containing gas, and a hydrocarbon-containing gas. As examples of the gas used during firing, nitrogen gas, oxygen gas, air, or a mixed gas of nitrogen gas and oxygen gas is preferable.

  As a calcination temperature, it is preferable that it is 500-900 degreeC, and it is more preferable that it is 550-700 degreeC. The firing time is preferably 0.5 to 48 hours, and more preferably 2 to 24 hours.

  The catalyst is preferably dried before calcination. When moisture is removed by rapid heating as in firing, when the moisture moves from within the alumina, the supported alkali metal compound moves with the moisture, and the supported state of the alkali metal compound becomes uneven. There is a fear. By drying the catalyst before calcination and appropriately removing moisture before calcination, the movement of the alkali metal compound at the time of calcination can be suppressed, and the supported state of the catalyst can be made uniform.

  As a drying method, a conventionally known method can be adopted, and the temperature is usually from room temperature to about 100 ° C., and the pressure is usually 0.001 to 1 MPa, which is atmospheric pressure. Is preferred. Drying can be performed in an air atmosphere or an inert gas atmosphere such as nitrogen gas, helium gas, argon gas, carbon dioxide, or the like. These atmospheres may contain water vapor.

  In the present invention, methylacetylene is produced by isomerizing propadiene in a mixture containing propadiene and halogenated aliphatic hydrocarbon in the presence of the above-described catalyst.

  Examples of the halogenated aliphatic hydrocarbon include chloropropenes such as 1-chloro-1-propene, 2-chloro-1-propene and 3-chloro-1-propene; chloropropanes such as 1-chloropropane and 2-chloropropane Dichloropropanes such as 1,2-dichloropropane, 1,1-dichloropropane, 1,3-dichloropropane, 2,2-dichloropropane; 1,2,3-trichloropropane, 1,1,2-tri Trichloropropanes such as chloropropane, 1,1,3-trichloropropane and 1,2,2-trichloropropane; chloropropines such as 1-chloro-1-propyne and 3-chloro-1-propyne; 1-bromo Bromopropenes such as -1-propene, 2-bromo-1-propene, 3-bromo-1-propene; 1-bromopropane; -Bromopropanes such as bromopropane; dibromopropanes such as 1,2-dibromopropane, 1,1-dibromopropane, 1,3-dibromopropane, 2,2-dibromopropane; 1,2,3-tribromo Tribromopropanes such as propane, 1,1,2-tribromopropane, 1,1,3-tribromopropane, 1,2,2-tribromopropane; 1-bromo-1-propyne, 3-bromo- Bromopropines such as 1-propyne; fluoropropenes such as 1-fluoro-1-propene, 2-fluoro-1-propene and 3-fluoro-1-propene; fluoropropanes such as 1-fluoropropane and 2-fluoropropane 1,2-difluoropropane, 1,1-difluoropropane, 1,3-difluoropropane, 2,2-difluoropropyl Difluoropropanes such as bread; trifluoro such as 1,2,3-trifluoropropane, 1,1,2-trifluoropropane, 1,1,3-trifluoropropane, 1,2,2-trifluoropropane, etc. Propanes; fluoropropines such as 1-fluoro-1-propyne and 3-fluoro-1-propyne; such as 1-iodo-1-propene, 2-iodo-1-propene and 3-iodo-1-propene Iodopropenes; iodopropanes such as 1-iodopropane and 2-iodopropane; 1,2-diiodopropane, 1,1-diiodopropane, 1,3-diiodopropane, 2,2-diiodopropane Diiodopropanes such as 1,2,3-triiodopropane, 1,1,2-triiodopropane, 1,1,3-triiodopropane, 1,2,2-tri Examples include triiodopropanes such as iodopropane; iodopropines such as 1-iodo-1-propyne and 3-iodo-1-propyne, and two or more of these may be contained in the mixture. Among the exemplified halogenated aliphatic hydrocarbons, at least one selected from the group consisting of 1-chloro-1-propene, 2-chloro-1-propene, 3-chloro-1-propene, 1-chloropropane and 2-chloropropane. Preferably it is a seed.

  The content of the halogenated aliphatic hydrocarbon in the mixture is preferably 0.000001 to 0.01 mol, more preferably 0.00001 to 0.0030 mol, relative to 1 mol of propadiene. 0.0003 to 0.0015 mol is more preferable.

  As the mixture, those obtained by dehydrohalogenation of halogenated propane and / or halogenated propene are preferable. Here, propadiene is obtained by dehydrohalogenation reaction of halogenated propane and / or halogenated propene, and usually in the mixture obtained after the reaction, unreacted halogenated propane and / or halogenated propene, Halogenated aliphatic hydrocarbons such as by-product halogenated propene and halogenated propyne are also included. In the present invention, when a mixture containing propadiene obtained by dehydrohalogenation reaction of halogenated propane and / or halogenated propene and halogenated aliphatic hydrocarbon is used, halogenated propane and / or halogenated. The case where the reaction mixture obtained by the dehydrohalogenation reaction of propene is used as it is and the case where the mixture containing propadiene and halogenated aliphatic hydrocarbon obtained by purifying the reaction mixture is used are included.

  Examples of the halogenated propane include monohalogenated propane such as 1-chloropropane, 2-chloropropane, 1-bromopropane, 2-bromopropane, 1-fluoropropane, 2-fluoropropane, 1-iodopropane and 2-iodopropane. 1,2-dichloropropane, 1,1-dichloropropane, 1,3-dichloropropane, 2,2-dichloropropane, 1,2-dibromopropane, 1,1-dibromopropane, 1,3-dibromopropane, 2,2-dibromopropane, 1,2-difluoropropane, 1,1-difluoropropane, 1,3-difluoropropane, 2,2-difluoropropane, 1,2-diiodopropane, 1,1-diiodopropane , 1,3-diiodopropane, 2,2-diiodopropane and the like 1,2,3-trichloropropane, 1,1,2-trichloropropane, 1,1,3-trichloropropane, 1,2,2-trichloropropane, 1,2,3-tribromopropane, 1, 1,2-tribromopropane, 1,1,3-tribromopropane, 1,2,2-tribromopropane, 1,2,3-trifluoropropane, 1,1,2-trifluoropropane, 1, 1,3-trifluoropropane, 1,2,2-trifluoropropane, 1,2,3-triiodopropane, 1,1,2-triiodopropane, 1,1,3-triiodopropane, 1, Examples include trihalogenated propane such as 2,2-triiodopropane. Examples of the halogenated propene include 1-chloro-1-propene, 2-chloro-1-propene, 3-chloro-1-propene, 1-bromo-1-propene, 2-bromo-1-propene, and 3-bromo. -1-propene, 1-fluoro-1-propene, 2-fluoro-1-propene, 3-fluoro-1-propene, 1-iodo-1-propene, 2-iodo-1-propene, 3-iodo-1 -Monohalogenated propene such as propene, dihalogenated propene and the like.

  The dehydrohalogenation reaction is preferably carried out in the presence of a predetermined catalyst, and a reaction temperature of about 200 to 1200 ° C. and a reaction pressure of about 0.01 to 5 MPa are suitable.

Examples of the dehydrohalogenation reaction method include a fixed bed method, a fluidized bed method, a moving bed method, and the like. Among them, the fixed bed method and the fluidized bed method are preferable. When a fixed bed method is adopted as a reaction method for dehydrohalogenation reaction, the supply rate of halogenated propane and / or halogenated propene is as follows: gas supply rate per liter of catalyst (L / h; 0 ° C., 1 Expressed in terms of atmospheric pressure), that is, GHSV (Gas Hourly Space Velocity), it is usually about ¹ to 20000 h ⁻¹ .

  The reaction mixture obtained by the dehydrohalogenation reaction is appropriately purified, and then as a mixture containing propadiene and halogenated aliphatic hydrocarbon obtained by the dehydrohalogenation reaction of halogenated propane and / or halogenated propene. It can be used for the isomerization described below. Purification can be performed, for example, by distillation or the like, whereby the content of halogenated aliphatic hydrocarbons relative to propadiene in the resulting mixture can be reduced.

  On the other hand, the isomerization of propadiene in the mixture described above may be performed in a batch system, a semi-batch system, or a continuous system. The temperature in isomerization is usually -30 to 600 ° C, preferably 0 to 100 ° C, and the pressure is usually 0.1 to 10 MPa.

  Isomerization may be performed in an inert gas atmosphere or an oxidizing gas atmosphere. Examples of the inert gas and the oxidizing gas include the same gases as exemplified in the heat treatment of alumina described above. In addition, when performing isomerization by a continuous type, you may supply an inert gas and oxidizing gas with a raw material. In the continuous reaction, for example, isomerization can be performed by adopting a fixed bed system under liquid phase conditions.

  In the isomerization, an organic solvent may be used. Examples of the organic solvent include aliphatic hydrocarbons such as methane, ethane, propane, butane, pentane, hexane, and octane; alicyclic hydrocarbons such as cyclopentane and cyclohexane; aromatic hydrocarbons such as benzene, toluene, and xylene; Examples thereof include aprotic polar solvents such as N, N-dimethylformamide and N, N-dimethylacetamide, and two or more of these may be used as necessary. Among the exemplified organic solvents, aliphatic hydrocarbons are preferable, and propane is more preferable.

  Isomerization is preferably performed under conditions where water and carbon dioxide are substantially absent. Thereby, it can suppress that the activity of a catalyst falls.

  Here, in this invention, the usage-amount of the catalyst in isomerization is 3.0 mol or more in conversion of the alkali metal element contained in a catalyst with respect to 1 mol of halogenated aliphatic hydrocarbons, Preferably it is 6.0. Make it more than moles. Thereby, a methylacetylene can be manufactured with a favorable yield. The upper limit of the amount of the catalyst used is suitably 100000 mol or less in terms of the alkali metal element contained in the catalyst with respect to 1 mol of the halogenated aliphatic hydrocarbon. The amount of the catalyst used in the case where two or more kinds of halogenated aliphatic hydrocarbons are contained in the mixture is the same as described above in terms of the total content of the halogenated aliphatic hydrocarbons converted to the alkali metal element contained in the catalyst. It may be within a specific range.

  The amount of the catalyst used is appropriately set so as to be within the specific range described above. However, the amount of the catalyst used relative to propadiene is converted to the alkali metal element contained in the catalyst in order to efficiently promote isomerization. In addition, it is preferably 0.0001 to 0.1 mol, more preferably 0.001 to 0.050 mol, and 0.001 to 0.030 mol with respect to 1 mol of propadiene. Further preferred.

  The post-treatment operation after the reaction is appropriately selected. For example, methylacetylene and propadiene can be separated by performing an operation such as distillation.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by these Examples.

In the following examples, the average pore radius of alumina was measured as follows.
<Measurement method of average pore radius>
After the alumina was dried at 120 ° C. for 4 hours, it was determined by mercury porosimetry using a pore volume measuring device “Autopore III9420” manufactured by MICROMERITICS.

<Preparation of catalyst>
Spherical γ-alumina (average pore radius 6.4 nm, pore volume 0.60 mL / g, BET surface area 106 m ² / g, 2.0 to 4.0 mm sphere) was used as a carrier. First, this support was heat-treated in an air atmosphere under conditions of a heat treatment temperature of 500 ° C. and a heat treatment time of 16 hours.

Next, the heat-treated γ-alumina was contact-treated with a solution containing an alkali metal compound. Specifically, 28.61 g of heat-treated γ-alumina was impregnated with an aqueous solution prepared by dissolving 7.20 g of potassium carbonate “K ₂ CO ₃ ” manufactured by Wako Pure Chemical Industries, Ltd. in 14.47 g of pure water. I let you. This contact treatment was performed in an air atmosphere, the treatment temperature was 23 ° C., and the treatment pressure was atmospheric pressure.

  Next, the potassium carbonate-carrying γ-alumina obtained by the contact treatment was dried before firing. Drying was performed by air-drying potassium carbonate-supported γ-alumina in an air atmosphere under conditions of a temperature of 20 to 30 ° C., a pressure of atmospheric pressure, and a drying time of 15 hours or more.

  Next, the dried potassium carbonate-supported γ-alumina was heated from room temperature (23 ° C.) to 620 ° C. over 1 hour under air flow, and then held at that temperature for 6 hours to be fired. The fired product was pulverized and sized to obtain a 10-30 mesh granular potassium-supported γ-alumina catalyst (A).

  The amount of potassium supported on the obtained catalyst (A) was calculated by ICP analysis using an ICP emission analyzer “ICPS-8100” manufactured by Shimadzu Corporation. The amount of potassium supported per gram of catalyst was: It was 2.56 mmol.

<Catalyst activity test>
First, 0.597 g of the obtained catalyst (A) and 3-chloro-1-propene manufactured by Tokyo Chemical Industry Co., Ltd. were placed in a 100 mL stainless steel (SUS) autoclave under a nitrogen gas atmosphere in a glove box. Was introduced at a rate of 0.0047 g (0.060 mmol) (see Table 1).

In addition, the usage-amount (mmol-potassium) of the catalyst in Table 1 and the content of the potassium ratio (molar ratio) with respect to 3-chloro- 1-propene are as follows.
-Amount of catalyst used (mmol-potassium): A value obtained by converting the amount of catalyst used to an alkali metal element (potassium) contained in the catalyst.
-Potassium ratio (molar ratio) to 3-chloro-1-propene: The amount of the catalyst used is an alkali metal element contained in the catalyst with respect to 1 mol of the halogenated aliphatic hydrocarbon (3-chloro-1-propene). It is the value converted into (potassium).

  Next, after reducing the pressure in the autoclave to -0.1 MPaG, 7.07 g of propadiene, 9.8 mg of methylacetylene and 15.20 g of propane as an organic solvent were introduced into the autoclave while cooling the autoclave in an ethanol / dry ice bath. . Then, the reaction was carried out at 30 ° C. and 1.0 to 1.1 MPa (absolute pressure) for 2 hours while stirring in the autoclave to isomerize propadiene in the presence of the catalyst (A).

  Note that propadiene, methylacetylene and propane were all introduced from the cylinder into the autoclave. The amount of propadiene, methylacetylene and propane charged was calculated from the weight reduction of the cylinder. 9.8 mg of methylacetylene introduced into the autoclave is contained as an impurity in propadiene.

  In addition, propadiene, methylacetylene and propane were all introduced into the autoclave in a gas state from a cylinder. Since the autoclave is cooled in an ethanol / dry ice bath (about −65 ° C.), all of propadiene, methylacetylene and propane immediately after being introduced into the autoclave are in a liquid state. Since the reaction was carried out under pressure, most of the propadiene, methylacetylene and propane remained in the liquid state during the reaction and therefore are liquid phase reactions.

  After the reaction, the reaction solution is analyzed by gas chromatography, propadiene conversion rate (hereinafter sometimes referred to as “PD conversion rate”) (%), methylacetylene yield (hereinafter referred to as “MA yield”). (%), And methylacetylene production amount per 1 g of catalyst (hereinafter sometimes referred to as “MA production amount”) (g-MA / g-cat.). It was shown in 1.

The PD conversion rate (%) was calculated from the formula: [number of moles of reacted propadiene / number of moles of supplied propadiene] × 100.
The MA yield (%) was calculated from the formula: [number of moles of produced methylacetylene / number of moles of supplied propadiene] × 100.
The MA production amount (g-MA / g-cat.) Was calculated from the formula: [methylacetylene production amount (g) / catalyst weight (g)].

  0.606 g of catalyst (A), 0.0094 g (0.120 mmol) of 3-chloro-1-propene, 7.00 g of propadiene, 9.5 mg of methylacetylene and 15.42 g of propane in the autoclave A catalyst activity test was conducted in the same manner as in Example 1 except that the catalyst was introduced into the catalyst. The results are shown in Table 1.

  0.602 g of catalyst (A), 0.019 g (0.240 mmol) of 3-chloro-1-propene, 8.72 g of propadiene, 12.2 mg of methylacetylene and 15.28 g of propane in the autoclave A catalyst activity test was conducted in the same manner as in Example 1 except that the catalyst was introduced into the catalyst. The results are shown in Table 1.

<Preparation of catalyst>
First, γ-alumina heat-treated as in Example 1 was obtained. Next, the heat-treated γ-alumina was contact-treated with a solution containing an alkali metal compound. In the contact treatment, 10.85 g of heat-treated γ-alumina is impregnated with an aqueous solution prepared by dissolving 1.16 g of potassium carbonate “K ₂ CO ₃ ” manufactured by Wako Pure Chemical Industries, Ltd. in 5.73 g of pure water. The procedure was the same as in Example 1 except that.

  Next, potassium carbonate-carrying γ-alumina obtained by the contact treatment was dried in the same manner as in Example 1. The dried potassium carbonate-supported γ-alumina was fired in the same manner as in Example 1 except that it was fired under a nitrogen gas flow, and the fired product was pulverized and sized to give 10-30 mesh granular potassium. A supported γ-alumina catalyst (B) was obtained. When the amount of potassium supported on the obtained catalyst (B) was calculated in the same manner as in Example 1, it was 1.28 mmol per 1 g of the catalyst.

<Catalyst activity test>
Instead of catalyst (A), 0.600 g of catalyst (B) is used, 0.0094 g (0.120 mmol) of 3-chloro-1-propene, 6.93 g of propadiene, 9.9 mg of methylacetylene and propane Was introduced into the autoclave at a rate of 15.57 g, and the catalyst activity test was conducted in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Example 1]
0.602 g of catalyst (A), 0.047 g (0.600 mmol) of 3-chloro-1-propene, 6.81 g of propadiene, 9.8 mg of methylacetylene and 15.89 g of propane in the autoclave A catalyst activity test was conducted in the same manner as in Example 1 except that the catalyst was introduced into the catalyst. The results are shown in Table 1.

  As is clear from Table 1, Examples 1 to 4 in which the amount of the catalyst used was 3.0 mol or more in terms of the alkali metal element contained in the catalyst with respect to 1 mol of the halogenated aliphatic hydrocarbon. Since the catalyst activity test showed better results than Comparative Example 1 in which the amount of catalyst used was less than 3.0 mol and 2.6 mol, methylacetylene could be produced in good yield. I can see that

[Reference Example 1]
<Preparation of catalyst>
Spherical γ-alumina (average pore radius 6.4 nm, pore volume 0.60 mL / g, BET surface area 106 m ² / g, 2.0 to 4.0 mm sphere) was used as a carrier. The carrier was heated from room temperature (23 ° C.) to 800 ° C. over 2.2 hours under air flow, and then calcined by holding at the same temperature for 3 hours to obtain a γ-alumina catalyst (a).

<Dehydrochlorination>
First, near the outlet of a quartz reaction tube with an inner diameter of 14 mm equipped with a thermometer sheath tube with an outer diameter of 4 mm, quartz wool is filled as a partition material, and the obtained catalyst (a) is 1 on the partition material. Filled with 0.0 g.

  Next, the reaction tube filled with the catalyst (a) was heated in an electric furnace, and the temperature of the reaction tube was increased while supplying nitrogen gas from the reaction tube inlet at a rate of 50 ml / min. Then, 1,2-dichloropropane manufactured by Wako Pure Chemical Industries, Ltd. was charged into the gas suction bottle and cooled to 0 ° C., then nitrogen gas was supplied to the gas suction bottle at a rate of 50 ml / min, Nitrogen gas entrained with 1,2-dichloropropane obtained by flowing into 1,2-dichloropropane is supplied from the reaction tube inlet instead of the supply nitrogen gas at the time of temperature increase (1,2-dichloropropane). Feed rate: 0.002 mol / hour, GHSV = 46), reaction started at a reaction pressure of 0.1 MPa.

  After the start of the reaction, the temperature of the catalyst layer is maintained at 500 ° C. ± 2 ° C., and 90 minutes after the start of the reaction, the reaction tube outlet gas is absorbed in a 30% potassium iodide aqueous solution, and TCD detection is performed on the unabsorbed gas. Each product was quantified by analysis with a gas chromatography equipped with a vessel.

  Next, 10% caustic soda, carbon tetrachloride, and a three-stage trap in contact with carbon tetrachloride absorb the halogenated propanes, and the first stage 10% caustic soda is extracted with carbon tetrachloride. In the stage, the absorption solution was directly analyzed by gas chromatography having an FID detector to quantify the halogenated propanes.

  Based on the following formulas (I) and (II), the conversion rate of 1,2-dichloropropane (hereinafter sometimes referred to as “DCP conversion rate”) (%), and the selectivity of each product ( %) And the results are shown in Table 2.

  In addition, in the conversion rate of 1,2-dichloropropane, the supply rate of 1,2-dichloropropane was calculated from the change in the weight of the gas suction bottle from the start to the end of supply. The product is methylacetylene (hereinafter sometimes referred to as “MA”); propadiene (hereinafter sometimes referred to as “PD”); propylene (hereinafter referred to as “C3 ′”). Chloropropenes consisting of 1-chloro-1-propene, 2-chloro-1-propene and 3-chloro-1-propene (hereinafter sometimes referred to as “CP ′”); 1-chloropropane And chloropropanes composed of 2-chloropropane (hereinafter sometimes referred to as “CP”).

[Reference Example 2]
<Preparation of catalyst>
As a carrier, “WH2C” manufactured by Nippon Enviro Chemicals, which is granular activated carbon, was used. 30.0 g of this carrier was put into an aqueous solution prepared by dissolving 22.40 g of iron sulfate heptahydrate “FeSO ₄ .7H ₂ O” manufactured by Wako Pure Chemical Industries, Ltd. and 500 ml of pure water, and urea. 14.65 g was dissolved, and iron hydroxide, which is a hydrolyzate of iron sulfate, was supported on activated carbon by precipitation.

  The obtained solid was filtered, washed with pure water and then dried to obtain a dried product. Then, the obtained dried product was heated from room temperature (23 ° C.) to 500 ° C. over 1.1 hours under a nitrogen gas flow, then held at the same temperature for 2 hours and calcined, and the iron oxide-supported activated carbon catalyst (B) was obtained.

<Dehydrochlorination>
The reaction was performed in the same manner as in Reference Example 1 except that the catalyst (b) was used instead of the catalyst (a). The results are shown in Table 2.

  As is apparent from Table 2, it can be seen that propadiene is obtained when a halogenated propane (1,2-dichloropropane) is dehydrohalogenated (dehydrochlorinated) in the presence of a catalyst.

Claims (7)

A method for producing methylacetylene, comprising isomerizing the propadiene in a mixture containing propadiene and a halogenated aliphatic hydrocarbon in the presence of a catalyst in which an alkali metal compound is supported on alumina,
The method for producing methylacetylene, wherein an amount of the catalyst used is 3.0 mol or more in terms of an alkali metal element contained in the catalyst with respect to 1 mol of the halogenated aliphatic hydrocarbon.   The production method according to claim 1, wherein the mixture is obtained by a dehydrohalogenation reaction of a halogenated propane and / or a halogenated propene.   The halogenated aliphatic hydrocarbon is at least one selected from the group consisting of 1-chloro-1-propene, 2-chloro-1-propene, 3-chloro-1-propene, 1-chloropropane and 2-chloropropane. The manufacturing method according to claim 1 or 2.   The production method according to claim 1, wherein the alumina is γ-alumina having an average pore radius of 4.5 nm or more.   The manufacturing method according to claim 1, wherein the alumina is γ-alumina having a pore volume of 0.40 mL / g or more.   The method according to claim 1, wherein the alkali metal compound is a potassium compound.   The manufacturing method according to claim 1, wherein the catalyst is obtained by calcining alumina after a contact treatment with a solution containing an alkali metal compound.