JP2019137663A - Method for producing unsaturated hydrocarbon - Google Patents

Abstract

To provide a method for producing an unsaturated hydrocarbon capable of efficiently converting an alkane with less catalyst deterioration as a novel production method of an unsaturated hydrocarbon.SOLUTION: There is provided a method for producing an unsaturated hydrocarbon which comprises a dehydrogenation step of bringing a raw material gas containing an alkane and steam into contact with a dehydrogenation catalyst to obtain a product gas containing at least one unsaturated hydrocarbon selected from the group consisting of an olefin and a conjugated diene, wherein the dehydrogenation catalyst contains a carrier and a supported metal containing tin and platinum supported on the carrier, the carrier contains a first metal oxide containing a group 4 element and a second metal oxide containing at least one element selected from the group consisting of a group 2 element and lanthanoid and the content of the second metal oxide in the carrier is 2.0 mass% or more and 20 mass% or less based on the total amount of the carrier.SELECTED DRAWING: None

Description

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

  Unsaturated hydrocarbons obtained by alkane dehydrogenation are required in large quantities in various fields, for example, as starting materials for industrial products. For example, unsaturated hydrocarbons are used for manufacturing detergents, high-octane gasoline, chemicals, etc., and also for manufacturing plastics.

  In particular, butene is widely used as a starting material for methyl ethyl ketone, alkylate gasoline and the like. As a method for producing butene, for example, a method of directly dehydrogenating n-butane using a heterogeneous dehydrogenation catalyst is known (for example, Patent Documents 1 to 4).

JP 2014-205135 A Japanese Patent Laying-Open No. 2015-027669 US Patent Application Publication No. 2014/0309470 US Pat. No. 6,433,241

  With increasing demand for unsaturated hydrocarbons, development of various alkane dehydrogenation methods differing in characteristics such as required characteristics of production equipment, operating costs, reaction efficiency, and the like has been demanded.

  An object of the present invention is to provide a method for producing an unsaturated hydrocarbon, which is a novel method for producing an unsaturated hydrocarbon with little catalyst deterioration and capable of efficiently converting alkane.

  The present inventors have found that alkane can be efficiently dehydrogenated by a dehydrogenation catalyst in which a specific metal element is supported on a specific support, and have completed the present invention.

  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 includes a support and a supported metal including tin and platinum supported on the support, and the support includes a first metal oxide including a Group 4 element; A second metal oxide containing at least one element selected from the group consisting of Group 2 elements and lanthanoids, and the content of the second metal oxide in the support is It is 2.0 mass% or more and 20 mass% or less on the basis of the total amount.

In one embodiment, the first metal oxide may contain at least one selected from the group consisting of ZrO ₂ and HfO ₂ .

  In one embodiment, the second metal oxide may contain CaO.

In one embodiment, the second metal oxide may include La ₂ O ₃ .

  In one embodiment, the content of the second metal oxide in the support may be 5.0% by mass or more and 10% by mass or less based on the total amount of the support.

  In one embodiment, the alkane may contain butane, the olefin may contain butene, and the conjugated diene may contain butadiene.

  According to the present invention, as a novel method for producing an unsaturated hydrocarbon, there is provided a method for producing an unsaturated hydrocarbon that is capable of efficiently converting alkane with little catalyst deterioration.

  Hereinafter, preferred embodiments 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 a carrier and a supported metal containing tin and platinum supported on the carrier. The carrier contains a first metal oxide containing a Group 4 element and a second metal oxide containing at least one element selected from the group consisting of Group 2 elements and lanthanoids. Yes. Furthermore, in the present embodiment, the content of the second metal oxide in the support is 2.0% by mass or more and 20% by mass or less based on the total amount of the support.

  According to the production method according to the present embodiment, by using a dehydrogenation catalyst in which a specific metal element is supported on a specific support, alkane can be reacted at a high conversion rate while suppressing catalyst deterioration, and efficiently. Unsaturated hydrocarbons can be obtained.

  The dehydrogenation catalyst used in the present embodiment is a solid catalyst that catalyzes a dehydrogenation reaction of alkane, and a support metal including tin and platinum is supported on a support including the first metal oxide and the second metal oxide. Catalyst.

The first metal oxide is a metal oxide containing a Group 4 element. Examples of the first metal oxide include TiO ₂ , ZrO ₂ and HfO ₂ . The first metal oxide preferably comprises at least one ZrO ₂ and HfO _2, more preferably containing ZrO _2, it is further preferred to include both an ZrO ₂ and HfO _2.

  The content of the first metal oxide is preferably 80% by mass or more, more preferably 90% by mass or more based on the total amount of the carrier. In addition, the content of the first metal oxide is preferably 98% by mass or less, more preferably 95% by mass or less, based on the total amount of the carrier. When the content of the first metal oxide is in the above range, catalyst deterioration is more significantly suppressed, and high activity tends to be maintained for a longer time.

The second metal oxide is a metal oxide containing at least one element selected from the group consisting of Group 2 elements and lanthanoids. Examples of the second metal oxide include MgO, CaO, SrO, BaO, La ₂ O _{3 and the} like. Of the second metal oxides, CaO is preferred as the metal oxide containing a Group 2 element. Of the second metal oxides, La ₂ O ₃ is preferable as the metal oxide containing a lanthanoid.

  The content of the second metal oxide is 2.0% by mass or more, preferably 5.0% by mass or more, based on the total amount of the carrier. Further, the content of the second metal oxide is 20% by mass or less, preferably 10% by mass or less, based on the total amount of the carrier. When the content of the second metal oxide is within the above range, catalyst deterioration is more significantly suppressed, and high activity tends to be maintained for a longer time.

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, there exists a tendency for the conversion rate of alkane to improve further. 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. Thereby, it can be set as the support | carrier which has sufficient intensity | strength which can be utilized industrially suitably. In the present specification, the specific surface area of the carrier is measured by a BET specific surface area meter using a nitrogen adsorption method.

  The supported amount of platinum (Pt) in the dehydrogenation catalyst may be, for example, 0.8% by mass or more, preferably 0.9% by mass or more, based on the total amount of the dehydrogenation catalyst. Further, the supported amount of Pt may be, for example, 5.0% by mass or less, 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 suitable size due to the dehydrogenation reaction, and the platinum surface area per unit platinum weight increases, so a more efficient reaction system can be realized.

  The supported amount of tin (Sn) in the dehydrogenation catalyst is, for example, 1.0% by mass or more, preferably 2.0% by mass or more, based on the total amount of the dehydrogenation catalyst. The amount of Sn supported is, for example, 5.0% by mass or less, preferably 3.0% by mass or less, based on the total amount of the dehydrogenation catalyst. When the supported amount of Sn is in the above range, not only the alkane conversion rate is further improved, but also catalyst deterioration is more significantly suppressed, and high activity tends to be maintained for a longer time.

  The supported metal to be supported may be supported as an oxide or may be supported as a single metal.

  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 precursor of a supported metal (platinum source and tin source), and the carrier containing the solution is kneaded. Thereafter, the solvent is removed by drying, and the obtained solid is fired, whereby the supported metal can be supported on the support.

  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 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 may further contain an inert gas such as nitrogen or argon, and may further contain steam. By containing steam in the raw material gas, the catalyst activity tends to be remarkably suppressed.

  When the raw material gas contains steam, the steam content is preferably 0.5 times mole or more, more preferably 1.0 times mole or more, more preferably 1.5 times mole or more with respect to the alkane. More preferably. 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.

  The source gas may further contain other components such as hydrogen, oxygen, carbon monoxide, carbon dioxide gas, olefins and dienes in addition to the above.

  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.

  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. 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 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 the reaction temperature is 500 ° C. or higher, the alkane tends to be more easily converted. When the reaction temperature is 700 ° C. or lower, catalyst deterioration is suppressed and high activity tends to be maintained over a longer period.

  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 dehydrogenation method according to the present embodiment brings the product gas containing the olefin obtained in the dehydrogenation step (hereinafter, also referred to as the first product gas) into contact with the second dehydrogenation catalyst. A step of performing a dehydrogenation 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 dehydrogenation method, a product gas containing more conjugated dienes 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, or 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 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 0.995 mL of water was prepared, and 1.0 g of ZrO ₂ —CaO support (Z-2986, first Elemental Chemical Co., Ltd., first metal oxide: 90.1% by mass (ZrO ₂ is about 88% by mass, HfO ₂ is about 2% by mass), second metal oxide: 9.9% by mass (CaO 9.9 mass%)) was added and kneaded. 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 66.6 mg of sodium stannate trihydrate was dissolved in 1.083 mL of water was prepared, and 1.0 g of the baked solid was added to this solution B and kneaded. Then, it dried in 130 degreeC oven overnight, and the solid after drying was baked at 550 degreeC for 3 hours by air circulation. Subsequently, the sodium compound contained in the obtained solid was removed with ion-exchanged water. Finally, hydrogen reduction was performed at 550 ° C. for 2 hours to obtain a catalyst A-1 carrying Pt and Sn. In catalyst A-1, the supported amount of Pt was 1.0% by mass, and the supported amount of Sn was 2.6% by mass.

[Catalyst synthesis example 2]
<Preparation of catalyst A-2>
Instead of ZrO ₂ —CaO support, ZrO ₂ —La ₂ O ₃ support (Z-1799, Daiichi Rare Element Chemical Co., Ltd., first metal oxide: 90.9% by mass (ZrO ₂ is about 89% by mass) HfO ₂ was about 2% by mass), the second metal oxide was 9.1% by mass (La ₂ O ₃ was 9.1% by mass)), and the amount of dilution water was changed in place of the solution A. Example of catalyst synthesis, except that 1.105 mL of solution was used, and that the solution used was 1.193 mL of water used for dissolving sodium stannate trihydrate instead of solution B. The catalyst was prepared in the same manner as in Example 1 to obtain Catalyst A-2. In the obtained catalyst A-2, the supported amounts of Pt and Sn were the same as the supported amounts of Pt and Sn in the catalyst A-1.

[Catalyst Synthesis Example 3]
<Preparation of catalyst B-1>
The MgAl ₂ O ₄ support was used instead of the ZrO ₂ —CaO support, the solution in which the amount of dilution water was 0.601 mL was used instead of the solution A, and the sodium stannate was used instead of the solution B. Catalyst B-1 was obtained in the same manner as in Catalyst Synthesis Example 1 except that a solution in which the amount of water used for dissolving the hydrate was 0.689 mL was used. In the obtained catalyst B-1, the supported amounts of Pt and Sn were the same as the supported amounts of Pt and Sn in the catalyst A-1.

[Catalyst Synthesis Example 4]
<Preparation of catalyst B-2>
A carrier having a different composition as a ZrO ₂ —CaO carrier (Z-2920, first rare element chemical industry, first metal oxide: 98.2% by mass (ZrO ₂ is about 96% by mass, HfO ₂ is about 2%) Mass%), the second metal oxide: 1.8 mass% (CaO is 1.8 mass%)), and instead of the solution A, a solution in which the amount of dilution water was 1.299 mL was used. The catalyst was prepared in the same manner as in Catalyst Synthesis Example 1, except that a solution in which the amount of water used for dissolving sodium stannate trihydrate was 1.387 mL was used instead of Solution B. Catalyst B-2 was obtained. In the obtained catalyst B-2, the supported amounts of Pt and Sn were the same as the supported amounts of Pt and Sn in the catalyst A-1.

[Catalyst Synthesis Example 5]
<Preparation of catalyst B-3>
Instead of the ZrO ₂ —CaO carrier, the ZrO ₂ —Y ₂ O ₃ carrier (Z-2987, Daiichi Rare Element Chemical Co., Ltd., first metal oxide: 60.1% by mass (ZrO ₂ is about 58% by mass) HfO ₂ was about 2% by mass), the second metal oxide was 39.9% by mass (Y ₂ O ₃ was 39.9% by mass)), and the amount of dilution water was changed in place of the solution A. Catalyst Synthesis Example 1 except that a solution of 1.357 mL was used and a solution in which the amount of water used for dissolving sodium stannate trihydrate was 1.445 mL was used instead of solution B. Catalyst preparation was performed in the same manner to obtain Catalyst B-3. In the obtained catalyst B-3, the supported amounts of Pt and Sn were the same as the supported amounts of Pt and Sn in the catalyst A-1.

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, while flowing a mixed gas of hydrogen and N ₂ (hydrogen: N ₂ = 1: 1 (mol ratio)) at 125 mL / min, the temperature of the reaction tube was increased to 550 ° C. and held at that temperature for 2 hours. . Subsequently, while maintaining the reaction tube at 550 ° C., a mixed gas of N ₂ and steam (water) (N ₂ : steam = 5.3: 3.2 (molar ratio)) at 54.5 mL / min for 20 minutes. Circulated. Thereafter, 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 1.0: 5.3: 3.2. The feed rate of the raw material gas to the tubular reactor was adjusted to 60.9 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 240 minutes had elapsed 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 butane concentration (unit: mass%) in the product gas collected at each time point was quantified.

From the butane concentration in the product gas, the butane conversion rate at the time of 60 minutes and 240 minutes was calculated. In addition, the butane conversion rate at the time of 60 minutes and 240 minutes is defined by the following formulas (1) and (2), respectively.
R ₁ = (1−M ₁ / M ₀ ) × 100 (1)
R ₂ = (1-M ₂ / M ₀ ) × 100 (2)
R ₁ in the formula (1) is the butane conversion rate after 60 minutes, M ₀ is the number of moles of n-butane in the raw material gas, and M ₁ is in the product gas after 60 minutes. The number of moles of n-butane. R ₂ in the formula (2) is the butane conversion rate after 240 minutes, M ₀ is the number of moles of n-butane in the raw material gas, and M ₂ is in the product gas after 240 minutes. The number of moles of n-butane.

  As a result of the calculation, the butane conversion rate was 75.9% after 60 minutes from the start of the reaction, and 67.6% after 240 minutes. The value obtained by dividing the latter by the former was 0. .891.

(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 was 72.4% after 60 minutes from the start of the reaction and 58.9% after 240 minutes, and the value obtained by dividing the latter by the former was 0.814. It was.

(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. The butane conversion rate was 58.0% after 60 minutes from the start of the reaction, and 46.6% after 240 minutes. The value obtained by dividing the latter by the former was 0.803. It was.

(Comparative 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 B-2 was used instead of the catalyst A-1. The butane conversion rate was 72.4% after 60 minutes from the start of the reaction and 45.7% after 240 minutes, and the value obtained by dividing the latter by the former was 0.631. It was.

(Comparative Example 3)
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-3 was used instead of the catalyst A-1. The butane conversion rate was 72.3% after 60 minutes from the start of the reaction and 50.4% after 240 minutes, and the value obtained by dividing the latter by the former was 0.697. It was.

(Comparative Example 4)
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-4 was used instead of the catalyst A-1. The butane conversion rate was 46.4% after 60 minutes from the start of the reaction and 42.8% after 240 minutes, and the value obtained by dividing the latter by the former was 0.922. It was.

(Comparative 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-5 was used instead of the catalyst A-1. The butane conversion rate was 19.8% after 60 minutes from the start of the reaction, and 17.2% after 240 minutes, and the value obtained by dividing the latter by the former was 0.869. It was.

  The results of Example 1, Example 2, and Comparative Examples 1-5 are shown in Table 1.

Claims (6)

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 a support and a supported metal containing tin and platinum supported on the support,
The carrier contains a first metal oxide containing a Group 4 element and a second metal oxide containing at least one element selected from the group consisting of Group 2 elements and lanthanoids;
The content of the second metal oxide in the carrier is 2.0% by mass or more and 20% by mass or less based on the total amount of the carrier.
A method for producing unsaturated hydrocarbons. The manufacturing method according to claim 1, wherein the first metal oxide includes at least one selected from the group consisting of ZrO ₂ and HfO ₂ .   The manufacturing method according to claim 1 or 2, wherein the second metal oxide contains CaO. The manufacturing method according to claim 1, wherein the second metal oxide includes La ₂ O ₃ .   5. The production method according to claim 1, wherein the content of the second metal oxide in the carrier is 5.0% by mass or more and 10% by mass or less based on the total amount of the carrier.   The production method according to any one of claims 1 to 5, wherein the alkane contains butane, the olefin contains butene, and the conjugated diene contains butadiene.