JP2018197215A - Manufacturing method of unsaturated hydrocarbon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an unsaturated hydrocarbon capable of efficiently obtaining an unsaturated hydrocarbon from an alkane as a new method for producing an unsaturated hydrocarbon. A dehydrogenation step is provided in which a raw material gas containing alkane and steam is brought into contact with a dehydrogenation catalyst to obtain a product gas containing at least one unsaturated hydrocarbon selected from the group consisting of olefins and conjugated diene. The dehydrogenation catalyst contains at least one metal element selected from the group consisting of Ga, In and Tl and Pt, and the content of the metal element in the dehydrogenation catalyst is 0.1 based on the total amount of the dehydrogenation catalyst. A method for producing an unsaturated hydrocarbon, which is ~ 5% by mass, and the content of Pt in the dehydrogenation catalyst is 0.9% by mass or more based on the total amount of the dehydrogenation catalyst. [Selection diagram] None

Description

  The present invention relates to a method for producing an unsaturated hydrocarbon.

  Due to motorization in recent years mainly in Asia, the demand for unsaturated hydrocarbons such as butadiene is expected to increase as a raw material for synthetic rubber. Examples of the method for producing butadiene include a method for producing conjugated diene by direct dehydrogenation of n-butane using a dehydrogenation catalyst (Patent Document 1), and a conjugated diene by oxidative dehydrogenation of n-butene. (Patent Documents 2 to 4) are known.

JP 2014-205135 A JP-A-57-140730 JP 60-1139 A JP 2003-220335 A

  With the increase in demand for unsaturated hydrocarbons, development of various methods for producing unsaturated hydrocarbons having different characteristics such as required characteristics, operating costs, reaction efficiency, etc. of production equipment is required.

  An object of the present invention is to provide a method for producing an unsaturated hydrocarbon capable of efficiently obtaining an unsaturated hydrocarbon from an alkane as a novel method for producing an unsaturated hydrocarbon.

  The present inventors have found that alkanes can be efficiently converted into unsaturated hydrocarbons by a catalyst in which a specific metal element is supported on a specific support, and the present invention has been completed.

  One aspect of the present invention is a dehydrogenation step of obtaining a product gas containing at least one unsaturated hydrocarbon selected from the group consisting of olefins and conjugated dienes by contacting a raw material gas containing alkane and steam with a dehydrogenation catalyst. It is related with the manufacturing method of unsaturated hydrocarbon provided with these. In this production method, the dehydrogenation catalyst contains at least one metal element selected from the group consisting of Ga, In and Tl, and Pt. Further, the content of the metal element in the dehydrogenation catalyst is 0.1 to 5% by mass based on the total amount of the dehydrogenation catalyst, and the content of Pt in the dehydrogenation catalyst is 0.00 on the total amount of the dehydrogenation catalyst. It is 9 mass% or more.

  In one embodiment, the dehydrogenation catalyst may contain In.

In one embodiment, the dehydrogenation catalyst may further contain a support supporting the metal element and Pt, and the support may contain MgAl ₂ O ₄ having a spinel structure.

  In one embodiment, the dehydrogenation catalyst may be a catalyst in which the metal element and Pt are supported on a carrier using a metal source that does not contain a chlorine atom.

  In one embodiment, the content of the metal element in the dehydrogenation catalyst may be 0.3 to 2% by mass based on the total amount of the dehydrogenation catalyst.

  In one embodiment, the molar ratio of steam to alkane in the source gas may be 1.5-4.

  In one embodiment, the alkane can be butane, the olefin can be butene, and the conjugated diene can be butadiene.

  In one embodiment, the product gas may contain at least olefins. In this embodiment, the production method may further include a second dehydrogenation step of contacting the product gas with a second dehydrogenation catalyst to convert at least a part of the olefin in the product gas into a conjugated diene. .

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of unsaturated hydrocarbon which can obtain unsaturated hydrocarbon efficiently from alkane is provided as a novel manufacturing method of unsaturated hydrocarbon.

  Hereinafter, a preferred embodiment of the present invention will be described.

  The method for producing an unsaturated hydrocarbon according to the present embodiment includes at least one unsaturated hydrocarbon selected from the group consisting of an olefin and a conjugated diene by bringing a raw material gas containing alkane and steam into contact with a dehydrogenation catalyst. A dehydrogenation step for obtaining a product gas is provided.

  In this embodiment, the dehydrogenation catalyst contains at least one metal element selected from the group consisting of Ga, In and Tl and Pt. The metal element content is 0.1 to 5% by mass based on the total amount of the dehydrogenation catalyst, and the Pt content is 0.9% by mass or more based on the total amount of the dehydrogenation catalyst.

  According to the production method according to the present embodiment, by using a dehydrogenation catalyst supporting a specific metal, an alkane can be reacted at a high conversion rate, and an unsaturated hydrocarbon can be obtained efficiently.

  The source gas contains alkane. The carbon number of the alkane may be the same as the carbon number of the target unsaturated hydrocarbon. The carbon number of the alkane may be, for example, 4 to 10 or 4 to 6.

  For example, the alkane may be a chain or a ring. Examples of the chain alkane include butane, pentane, hexane, heptane, octane, decane, and the like. More specifically, examples of the linear alkane include n-butane, n-pentane, n-hexane, n-heptane, n-octane, and n-decane. Examples of the branched alkane include isobutane, isopentane, 2-methylpentane, 3-methylpentane, 2,3-dimethylpentane, isoheptane, isooctane, and isodecane. Examples of the cyclic alkane include cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclodecane, and methylcyclohexane. The source gas may contain one kind of alkane or two or more kinds.

  In the source gas, the partial pressure of alkane may be 1.0 MPa or less, 0.1 MPa or less, or 0.01 MPa or less. By reducing the alkane partial pressure of the source gas, the alkane conversion rate can be further improved.

  The partial pressure of alkane in the raw material gas is preferably 0.001 MPa or more, and more preferably 0.005 MPa or more, from the viewpoint of reducing the reactor size with respect to the raw material flow rate.

  The source gas further includes steam. By containing steam in the raw material gas, the catalyst activity tends to be remarkably suppressed. The steam content is preferably 0.5 times mol or more, more preferably 1.0 times mol or more, and even more preferably 1.5 times mol or more with respect to the alkane. Further, the steam content may be, for example, 50 times mol or less, preferably 10 times mol or less, more preferably 4 times mol or less with respect to alkane. That is, in the raw material gas, the molar ratio of steam to alkane is preferably 0.5 or more, more preferably 1.0 or more, and more preferably 1.5 or more. The molar ratio of steam to alkane is preferably 50 or less, more preferably 10 or less, and still more preferably 4 or less.

  The source gas may further contain an inert gas such as nitrogen or argon. In addition to the above, the raw material gas may further contain other components such as hydrogen, oxygen, carbon monoxide, carbon dioxide, olefins, and dienes.

  In the present embodiment, the product gas contains at least one unsaturated hydrocarbon selected from the group consisting of olefins and conjugated dienes. The number of carbon atoms of the olefin and conjugated diene may be the same as the carbon number of the alkane, for example, 4 to 10 or 4 to 6.

  Examples of olefins include butene, pentene, hexene, heptene, octene, nonene, decene and the like, and these may be any isomer. Examples of the conjugated diene include 1,3-butadiene, 1,3-pentadiene, isoprene, 1,3-hexadiene, 1,3-heptadiene, 1,3-octadiene, 1,3-nonadiene, and 1,3-decadiene. Etc. The product gas may contain one kind of unsaturated hydrocarbon, and may contain two or more kinds of unsaturated hydrocarbons. For example, the product gas may include olefins and conjugated dienes.

  Below, the dehydrogenation catalyst in this embodiment is explained in full detail.

  The dehydrogenation catalyst is a solid catalyst that catalyzes the dehydrogenation reaction of alkane, and is a catalyst that contains at least one metal element selected from the group consisting of Ga, In, and Tl and Pt.

  In a preferred embodiment, the dehydrogenation catalyst may be a catalyst in which the metal element and Pt are supported on a carrier, that is, a catalyst containing the carrier and the metal element and Pt supported on the carrier. . Hereinafter, the metal element and Pt supported on the carrier may be collectively referred to as a supported metal.

Examples of the support include alumina (Al ₂ O ₃ ), silica (SiO ₂ ), silica alumina (SiO ₂ —Al ₂ O ₃ ), titania (TiO ₂ ), zirconia (ZrO ₂ ), and magnesia alumina (MgAl ₂ O). ₄ ). Among these, as the carrier, a carrier containing MgAl ₂ O ₄ is preferable, and a carrier containing MgAl ₂ O ₄ having a spinel structure is particularly preferable.

The specific surface area of the carrier may be, for example, 30 m ² / g or more, and preferably 50 m ² / g or more. Thereby, the effect of increasing the conversion rate of alkane is produced. The specific surface area of the carrier may be, for example, 1000 m ² / g or less, and preferably 500 m ² / g or less. By having such a specific surface area, a carrier having sufficient strength that can be suitably used industrially can be obtained.

  The method for preparing the carrier is not particularly limited, and may be, for example, a coprecipitation method, a deposition method, a kneading method, an impregnation method, a pore filling method, or the like. Among these, the impregnation method or the pore filling method is preferable from the viewpoint of easily obtaining the above-described suitable specific surface area. As a specific example of the impregnation method, for example, a support is prepared by adding alumina to a solution in which an inorganic salt of a Group 2 metal is dissolved, stirring, removing the solvent under reduced pressure, drying and firing. Can do.

  The dehydrogenation catalyst contains at least one metal element selected from the group consisting of Ga, In and Tl, and Pt. The metal element is preferably at least one selected from the group consisting of Ga and In, and more preferably In.

  The amount of the metal element supported is 0.1% by mass or more, preferably 0.3% by mass or more, based on the total amount of the dehydrogenation catalyst. In addition, the supported amount of the metal element is 5% by mass or less, preferably 2% by mass or less, based on the total amount of the dehydrogenation catalyst. When the content of the metal element in the dehydrogenation catalyst is in the above range, catalyst deterioration is suppressed and high activity tends to be maintained for a longer period of time.

  The supported amount of Pt is 0.9% by mass or more, preferably 1.0% by mass or more, based on the total amount of the dehydrogenation catalyst. The amount of Pt supported is preferably 5.0% by mass or less, more preferably 3.0% by mass or less, based on the total amount of the dehydrogenation catalyst. With such a loading amount, the Pt particles formed on the catalyst have a size suitable for the dehydrogenation reaction, and the platinum surface area per unit platinum weight increases, so that a more efficient reaction system can be realized.

  The supporting method of the supporting metal is not particularly limited, and examples thereof include an impregnation method, a deposition method, a coprecipitation method, a kneading method, an ion exchange method, and a pore filling method.

  One aspect of the loading method is shown below. First, a carrier is added to a solution containing a supported metal precursor, and the solution is stirred. Thereafter, the solvent is removed under reduced pressure, and the solid obtained after drying is calcined, whereby the supported metal can be supported on the carrier.

  In the above supporting method, the supporting metal precursor may be, for example, a metal salt or a complex. The metal salt of the supported metal may be, for example, an inorganic salt, an organic acid salt, or a hydrate thereof. Inorganic salts may be, for example, sulfates, nitrates, chlorides, phosphates, carbonates and the like. The organic acid salt may be, for example, acetate, oxalate and the like. The supported metal complex may be, for example, an alkoxide complex or an ammine complex.

  The precursor of the supported metal is preferably a metal source containing no chlorine atom. By using a metal source that does not contain chlorine atoms as a precursor, corrosion of the apparatus during catalyst preparation can be prevented.

  Firing can be performed, for example, in an air atmosphere or an oxygen atmosphere. Firing may be performed in one stage, or may be performed in two or more stages. The firing temperature may be any temperature as long as the precursor of the supported metal can be decomposed, and may be, for example, 200 to 1000 ° C or 400 to 800 ° C. In addition, when performing multi-stage baking, at least one step should just be the said baking temperature. The firing temperature at the other stage may be in the same range as described above, for example, and may be 100 to 200 ° C.

  The dehydrogenation catalyst may further contain a molding aid from the viewpoint of improving moldability. The molding aid may be, for example, a thickener, a surfactant, a water retention material, a plasticizer, a binder material, or the like.

  The shape of the dehydrogenation catalyst is not particularly limited, and may be, for example, a pellet shape, a granule shape, a honeycomb shape, a sponge shape, or the like.

  A dehydrogenation catalyst that has been subjected to a reduction treatment as a pretreatment may be used. The reduction treatment can be performed, for example, by holding the dehydrogenation catalyst at 40 to 600 ° C. in a reducing gas atmosphere. The holding time may be, for example, 0.05 to 24 hours. The reducing gas may contain hydrogen, carbon monoxide, etc., for example. By using the dehydrogenation catalyst subjected to the reduction treatment, the initial induction period of the dehydrogenation reaction can be shortened. The initial induction period means a state in which the supported metal in the dehydrogenation catalyst is reduced and is in an active state, and the activity of the catalyst is low.

  Next, the dehydrogenation process in this embodiment will be described in detail.

  The dehydrogenation step is a step in which a raw material gas is brought into contact with a dehydrogenation catalyst to perform an alkane dehydrogenation reaction to obtain a product gas containing unsaturated hydrocarbons.

  The dehydrogenation step may be performed, for example, by using a reactor filled with a dehydrogenation catalyst and circulating a raw material gas through the reactor. As the reactor, various reactors used for a gas phase reaction with a solid catalyst can be used. Examples of the reactor include a fixed bed reactor, a radial flow reactor, and a tubular reactor.

  The reaction type of the dehydrogenation reaction may be, for example, a fixed bed type, a moving bed type, or a fluidized bed type. Among these, the fixed bed type is preferable from the viewpoint of equipment cost.

  The reaction temperature of the dehydrogenation reaction, that is, the temperature in the reactor, may be 300 to 800 ° C. or 500 to 700 ° C. from the viewpoint of reaction efficiency. If reaction temperature is 500 degreeC or more, there exists a tendency for the production amount of unsaturated hydrocarbon to increase further. If reaction temperature is 700 degrees C or less, there exists a tendency for high activity to be maintained over a long period of time.

  The reaction pressure, that is, the atmospheric pressure in the reactor may be 0.01 to 1 MPa, may be 0.05 to 0.8 MPa, and may be 0.1 to 0.5 MPa. When the reaction pressure is in the above range, the dehydrogenation reaction is more likely to proceed, and a further excellent reaction efficiency tends to be obtained.

When the dehydrogenation step is performed in a continuous reaction mode in which the raw material gas is continuously supplied, the weight space velocity (hereinafter referred to as “WHSV”) may be 0.1 h ⁻¹ or more, and 1.0 h. it may also be ^-1 or more, may be at 100h ^-1 or less, may be ^{30h -1} or less. Here, WHSV is the ratio (supply rate / catalyst mass) of the feed rate (supply rate / time) of the raw material gas to the catalyst mass in a continuous reaction apparatus. In addition, the usage amount of the raw material gas and the catalyst may be appropriately selected in a more preferable range according to the reaction conditions, the activity of the catalyst, etc., and WHSV is not limited to the above range.

  In the dehydrogenation step, the reactor may be further charged with a catalyst other than the dehydrogenation catalyst (hereinafter also referred to as the first dehydrogenation catalyst).

  For example, in the present embodiment, a second dehydrogenation catalyst that catalyzes a dehydrogenation reaction from an olefin to a conjugated diene may be further charged after the first dehydrogenation catalyst of the reactor. Since the first dehydrogenation catalyst is excellent in the reaction activity of the dehydrogenation reaction from the alkane to the olefin, the second dehydrogenation catalyst is filled in the subsequent stage of the first dehydrogenation catalyst. The proportion of conjugated dienes can be increased.

  In addition, the production method according to the present embodiment includes contacting the product gas containing the olefin obtained in the dehydrogenation step (hereinafter also referred to as the first product gas) with the second dehydrogenation catalyst to dehydrate the olefin. A step of performing an elementary reaction to obtain a second product gas containing a conjugated diene (hereinafter also referred to as a second dehydrogenation step) may be further provided. According to such a production method, a product gas containing more conjugated diene can be obtained.

  As the second dehydrogenation catalyst, any olefin dehydrogenation catalyst can be used without particular limitation. For example, as the second dehydrogenation catalyst, a noble metal catalyst, a catalyst containing Fe and K, a catalyst containing Mo and the like can be used.

  The dehydrogenation reaction conditions in the second dehydrogenation step may be the same as the dehydrogenation reaction conditions in the first dehydrogenation step.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited to an Example.

[Catalyst Synthesis Example 1]
<Preparation of carrier A-1>
15 g of alumina classified to 0.5 to 1 mm (Neobead GB-13, manufactured by Mizusawa Chemical Co., Ltd., pH of a suspension suspended in water at a concentration of 1% by mass: 7.9), 18 A solution of .8 g Mg (NO ₃ ) ₂ .6H ₂ O dissolved in 56 mL water was added. The obtained mixed solution was stirred at 40 ° C. and 0.015 MPaA for 30 minutes using a rotary evaporator, and stirred at 40 ° C. and normal pressure for 30 minutes. Thereafter, water was removed under reduced pressure while stirring the mixture. The resulting solid was dried in an oven at 130 ° C. overnight. Next, the dried solid was calcined at 550 ° C. for 3 hours and at 800 ° C. for 3 hours under air flow. A solution obtained by dissolving 18.8 g of Mg (NO ₃ ) ₂ .6H ₂ O in 56 mL of water was added to the obtained solid again, and the same procedure was repeated to support A-1 containing MgAl ₂ O _4. Got.

<Preparation of catalyst A-1>
A solution A obtained by diluting 0.101 mL of a dinitrodiamine platinum nitric acid solution having a Pt concentration of 100 g / L with 0.601 mL of water was prepared, and 1.0 g of the carrier A-1 was impregnated with the solution A. Then, it dried in 130 degreeC oven overnight, and the solid after drying was baked at 550 degreeC for 3 hours by air circulation. Next, a solution B in which 9.3 mg of In (NO ₃ ) ₃ .3H ₂ O was dissolved in 0.606 mL of water was prepared, and this fired solid was impregnated with the fired solid. Then, it dried in 130 degreeC oven overnight, and the solid after drying was baked at 550 degreeC for 3 hours by air circulation. Finally, hydrogen reduction was performed at 550 ° C. for 2 hours to obtain a catalyst A-1 carrying Pt and In. In catalyst A-1, the supported amount of Pt was 1.0 mass%, and the supported amount of In was 0.29 mass%.

[Catalyst synthesis example 2]
<Preparation of catalyst A-2>
The catalyst was prepared in the same manner as in Catalyst Synthesis Example 1, except that a solution in which 18.6 mg of In (NO ₃ ) ₃ .3H ₂ O was dissolved in 0.608 mL of water was used instead of the solution B. Catalyst A-2 was obtained. In the obtained catalyst A-2, the supported amount of Pt was 1.0% by mass, and the supported amount of In was 0.59% by mass.

[Catalyst Synthesis Example 3]
<Preparation of catalyst A-3>
The catalyst was prepared in the same manner as in Catalyst Synthesis Example 1, except that a solution obtained by dissolving 27.8 mg of In (NO ₃ ) ₃ .3H ₂ O in 0.607 mL of water was used instead of the solution B. Catalyst A-3 was obtained. In the obtained catalyst A-3, the supported amount of Pt was 1.0% by mass, and the supported amount of In was 0.88% by mass.

[Catalyst Synthesis Example 4]
<Preparation of catalyst A-4>
The catalyst was prepared in the same manner as in Catalyst Synthesis Example 1, except that a solution in which 37.1 mg of In (NO ₃ ) ₃ .3H ₂ O was dissolved in 0.606 mL of water was used instead of the solution B. Catalyst A-4 was obtained. In the obtained catalyst A-4, the supported amount of Pt was 1.0% by mass, and the supported amount of In was 1.16% by mass.

[Catalyst Synthesis Example 5]
<Preparation of catalyst A-5>
The catalyst was prepared in the same manner as in Catalyst Synthesis Example 1, except that a solution prepared by dissolving 74.2 mg of In (NO ₃ ) ₃ .3H ₂ O in 0.600 mL of water was used instead of the solution B. Catalyst A-5 was obtained. In the obtained Catalyst A-5, the supported amount of Pt was 1.0% by mass, and the supported amount of In was 2.30% by mass.

[Catalyst Synthesis Example 6]
<Preparation of catalyst B-1>
A catalyst was prepared in the same manner as in Catalyst Synthesis Example 1 except that the impregnation with the solution B was not performed to obtain a catalyst B-1. In the obtained catalyst A-5, the supported amount of Pt was 1.0% by mass, and the supported amount of In was 0% by mass.

Example 1
1.0 g of catalyst A-1 was charged into a tubular reactor, and the reaction tube was connected to a fixed bed flow reactor. Next, the upper layer of the reaction tube was heated to 550 ° C. while flowing a mixed gas of hydrogen and N ₂ (hydrogen: N ₂ = 5: 5 (mol ratio)) at 50 mL / min, and the temperature was increased to 550 ° C. for 1 hour. Retained. At the same time, the lower layer of the reaction tube was heated to 600 ° C. and held at that temperature for 1 hour. Subsequently, a mixed gas (raw material gas) of n-butane, N ₂ and steam (water) was supplied to the reactor, and n-butane in the raw material gas was dehydrogenated. Here, the molar ratio of n-butane, N ₂ and steam in the raw material gas was adjusted to 1: 5: 3. The feed rate of the raw material gas to the tubular reactor was adjusted to 62 mL / min. The WHSV with respect to the total amount of the catalyst was adjusted to 1.0 h- ¹ . The pressure of the raw material gas in the tubular reactor was adjusted to atmospheric pressure.

  When 60 minutes passed from the start of the reaction, the product (product gas) of the dehydrogenation reaction was collected from the tubular reactor. Further, when 300 minutes passed from the reaction start time, the product (product gas) of the dehydrogenation reaction was collected from the tubular reactor. The reaction start time is the time when the supply of the source gas is started. The product gas collected at each time point was analyzed using a gas chromatograph (TCD-GC) equipped with a thermal conductivity detector. As a result of analysis, it was confirmed that the product gas contained butene and 1,3-butadiene. Based on the gas chromatograph, the butene concentration (unit: mass%) and the butadiene concentration (unit: mass%) in the product gas collected at each time point were quantified.

From the concentration of butane, butene and 1,3-butadiene in the product gas, the butane conversion rate, butene yield and butadiene yield at the time of 60 minutes and 180 minutes were calculated. The butane conversion rate is defined by the following formula (1), the butadiene yield is defined by the following formula (2), and the butene yield is defined by the following formula (3).
R _Y1 = M _a / M ₀ × 100 (1)
R _Y2 = M _b / M ₀ × 100 (2)
R _Y3 = M _P / M ₀ × 100 (3)
R _Y1 in Formula (1) is a butane conversion, M ₀ is the number of moles of n- butane in the feed gas, M _a is the number of moles of n- butane in the product gas.
In Formula (2), R _Y1 is the butadiene yield, M ₀ is the number of moles of n-butane in the raw material gas, and M _b is the number of moles of 1,3-butadiene in the product gas.
_{R Y2} in Formula (3) is a butene yield, _{M 0} is the number of moles of n- butane in the feed gas, _{M P} is in the product gas of 1-butene, t-2-butene and c- The number of moles of 2-butene.

  As a result of the calculation, the butane conversion rate, butene yield and butadiene yield after 60 minutes were 57.2%, 35.2%, 2.3%, butane conversion rate and butene yield after 180 minutes, respectively. The rate and butadiene yield were 40.4%, 25.6%, and 2.7%, respectively.

(Example 2)
The dehydrogenation reaction of n-butane and the analysis of the product gas were performed in the same manner as in Example 1 except that the catalyst A-2 was used instead of the catalyst A-1. The butane conversion rate, butene yield and butadiene yield after 60 minutes from the start of the reaction were 65.3%, 44.1%, 3.3%, butane conversion rate and butene yield after 180 minutes, respectively. The rate and butadiene yield were 49.1%, 35.1%, and 4.0%, respectively.

Example 3
A dehydrogenation reaction of n-butane and analysis of the product gas were performed in the same manner as in Example 1 except that the catalyst A-3 was used instead of the catalyst A-1. The butane conversion rate, butene yield and butadiene yield after 60 minutes from the start of the reaction were 62.1%, 47.3%, 6.1%, butane conversion rate and butene yield after 180 minutes, respectively. The rate and butadiene yield were 55.9%, 43.6% and 6.6%, respectively.

(Example 4)
A dehydrogenation reaction of n-butane and analysis of the product gas were performed in the same manner as in Example 1 except that the catalyst A-4 was used instead of the catalyst A-1. The butane conversion rate, butene yield and butadiene yield after 60 minutes from the start of the reaction were 68.2%, 51.7%, 7.0%, butane conversion rate and butene yield after 180 minutes, respectively. The rate and butadiene yield were 56.7%, 43.5%, and 7.5%, respectively.

(Example 5)
The dehydrogenation reaction of n-butane and the analysis of the product gas were performed in the same manner as in Example 1 except that the catalyst B-2 was used instead of the catalyst A-1. The butane conversion rate, butene yield and butadiene yield after 60 minutes from the start of the reaction were 55.6%, 42.7%, 5.7%, butane conversion rate and butene yield after 180 minutes, respectively. The rate and butadiene yield were 48.1%, 34.1%, and 6.6%, respectively.

(Comparative Example 1)
The dehydrogenation reaction of n-butane and the analysis of the product gas were performed in the same manner as in Example 1 except that the catalyst B-1 was used instead of the catalyst A-1. Butane conversion rate, butene yield, and butadiene yield after 60 minutes from the start of the reaction were 41.5%, 7.5%, 0.4%, butane conversion rate, butene yield after 180 minutes, respectively. The rate and butadiene yield were 31.5%, 6.8%, and 0.4%, respectively.

  The results of Examples 1 to 5 and Comparative Example 1 are shown in Table 1.

Claims (8)

A dehydrogenation step of obtaining a product gas containing at least one unsaturated hydrocarbon selected from the group consisting of olefins and conjugated dienes by contacting a raw material gas containing alkane and steam with a dehydrogenation catalyst;
The dehydrogenation catalyst contains at least one metal element selected from the group consisting of Ga, In and Tl, and Pt;
The content of the metal element in the dehydrogenation catalyst is 0.1 to 5% by mass based on the total amount of the dehydrogenation catalyst,
The method for producing an unsaturated hydrocarbon, wherein the Pt content in the dehydrogenation catalyst is 0.9 mass% or more based on the total amount of the dehydrogenation catalyst.   The production method according to claim 1, wherein the dehydrogenation catalyst contains In. The dehydrogenation catalyst further comprises a carrier supporting the metal element and the Pt;
Wherein said carrier comprises a MgAl ₂ O ₄ having a spinel structure, the manufacturing method according to claim 1 or 2.   The production method according to any one of claims 1 to 3, wherein the dehydrogenation catalyst is a catalyst in which the metal element and the Pt are supported on a carrier using a metal source containing no chlorine atom.   5. The production method according to claim 1, wherein the content of the metal element in the dehydrogenation catalyst is 0.3 to 2 mass% based on the total amount of the dehydrogenation catalyst.   The manufacturing method as described in any one of Claims 1-5 whose molar ratio with respect to the said alkane of the said steam is 1.5-4 in the said source gas.   The production method according to any one of claims 1 to 6, wherein the alkane is butane, the olefin is butene, and the conjugated diene is butadiene. The product gas contains at least olefin,
8. The method according to claim 1, further comprising a second dehydrogenation step of contacting the product gas with a second dehydrogenation catalyst to convert at least a part of the olefin in the product gas into a conjugated diene. The production method according to item.