WO2015152160A1 - Method for producing unsaturated hydrocarbon - Google Patents

Abstract

[Problem] To provide a method for producing an unsaturated hydrocarbon by dehydrogenating a hydrocarbon with use of a dehydrogenation catalyst, which stably produces an unsaturated hydrocarbon, namely an olefin and/or a diene for a long period of time by effectively suppressing volatilization of zinc from the dehydrogenation catalyst. [Solution] A method for producing an unsaturated hydrocarbon which comprises a step wherein a starting material-containing gas (1), which contains a hydrocarbon, is brought into contact with zinc metal and/or a zinc compound, and then the starting material-containing gas (1) is brought into contact with a dehydrogenation catalyst which contains zinc as one active component, thereby performing a dehydrogenation reaction of the hydrocarbon so as to produce an unsaturated hydrocarbon.

Description

Process for producing unsaturated hydrocarbons

The present invention relates to a method for producing an unsaturated hydrocarbon by performing a hydrocarbon dehydrogenation reaction.

Unsaturated hydrocarbons, especially olefins and dienes, are very useful as basic raw materials for various derivatives in the petrochemical industry. Representative lower olefins and dienes include propylene, 1-butene, 2-butene, isobutene, 1,3-butadiene and the like. These lower olefins and dienes are also known to be produced by dehydrogenating the corresponding paraffins and / or olefins. For example, a catalyst having chromium oxide supported on an alumina support, an alumina support or zinc aluminate. It is known that such a catalyst having platinum supported on a spinel carrier is suitable for its production (Non-patent Document 1). Patent Documents 1 to 9 disclose that a catalyst in which platinum and zinc are supported on a zeolite carrier exhibits high activity over a long period of time as compared with other catalyst systems.

On the other hand, since the melting point of metallic zinc is as low as about 420 ° C. and has a high vapor pressure, in the case of a dehydrogenation catalyst containing metallic zinc as an active component, metallic zinc is used under typical dehydrogenation reaction conditions that require high temperature and low pressure. Continues to evaporate from the catalyst, resulting in irreversible degradation of the catalyst.

As a method of suppressing the volatilization of zinc from the catalyst, for example, the text of Patent Document 7 describes that the addition of a Group IVB element such as zirconium is effective. Patent Document 10 discloses a method of adding gallium to a zeolite carrying zinc as a propane aromatization catalyst. Patent Document 11 uses a zeolite containing zinc as a lower hydrocarbon aromatization catalyst. A method of supplying carbon dioxide, steam, thiophene and the like together with the raw material gas is disclosed. Furthermore, Patent Document 12 discloses that the formation of zinc aluminate by the reaction of the zinc component contained in the aromatization catalyst and alumina greatly contributes to the stabilization of zinc.

U.S. Pat. No. 4,962,266 US Pat. No. 5,126,502 US Pat. No. 5,208,201 US Pat. No. 5,324,702 US Pat. No. 5,453,558 US Pat. No. 6,197,717 US Pat. No. 6,555,724 International Publication 2012/020743 JP 2012-026197 A U.S. Pat. No. 4,490,569 U.S. Pat. No. 4,849,568 JP-A-10-52646

However, when the present inventors applied the zinc volatilization suppression technology found in the development of these aromatization catalysts to a dehydrogenation catalyst, all of the obtained effects were small or accompanied by a significant decrease in activity. Thus, it was found that the above zinc volatilization suppression technology is never satisfactory. Therefore, establishment of an effective zinc stabilization method applicable to a dehydrogenation catalyst is desired.

Therefore, the present invention provides a method for producing an unsaturated hydrocarbon by dehydrogenating a hydrocarbon using a dehydrogenation catalyst, and effectively suppressing the volatilization of zinc from the dehydrogenation catalyst. It is an object of the present invention to provide a method for stably producing unsaturated hydrocarbons, that is, olefins or dienes.

As a result of intensive studies to solve the above-mentioned problems, the present inventors made contact with the catalyst after bringing the raw material-containing gas into contact with metallic zinc and / or a zinc compound, or made the raw material-containing gas containing zinc vapor into the catalyst. It has been found that, by contacting, volatilization of zinc from the catalyst can be effectively suppressed, and as a result, unsaturated hydrocarbons, that is, olefins and dienes can be produced stably over a long period of time.

That is, in one embodiment of the present invention, the raw material-containing gas (1) containing hydrocarbon is brought into contact with zinc metal or zinc compound or both, and then brought into contact with a dehydrogenation catalyst containing zinc as one of the active components. , A method for producing an unsaturated hydrocarbon (hereinafter also referred to as “production method (1)”), which comprises a step of producing an unsaturated hydrocarbon by dehydrogenating the hydrocarbon.

In another embodiment of the present invention, the raw material-containing gas (2) containing hydrocarbon and zinc vapor is brought into contact with a dehydrogenation catalyst containing zinc as one of the active components, and the hydrocarbon is dehydrogenated. This is a method for producing an unsaturated hydrocarbon including a step of producing unsaturated hydrocarbon (hereinafter also referred to as “production method (2)”).
The said raw material containing gas (2) can be obtained by making the said raw material containing gas (1) contact metal zinc or a zinc compound, or both.

It is preferable that the reaction temperature of the dehydrogenation reaction is 300 to 800 ° C. and the reaction pressure is 0.01 to 1 MPa.
The partial pressure of zinc vapor contained in the raw material-containing gas (2) is not more than the vapor pressure of zinc at the reaction temperature of the dehydrogenation reaction. The zinc vapor source is preferably metallic zinc or zinc oxide or both.

The hydrocarbon as the raw material is preferably at least one selected from propane, n-butane and isobutane, or n-butene.
In the production method (1), the raw material-containing gas (1) preferably further contains water vapor and / or hydrogen.
In the production method (2), the raw material-containing gas (2) preferably further contains water vapor and / or hydrogen.

Further, a preferred form as the dehydrogenation catalyst is a catalyst in which zeolite is used as a carrier and zinc and a Group VIIIA metal are supported as active components. The amount of zinc contained in such a catalyst is preferably 0.01 to 15% by weight, with the total weight of the catalyst being 100% by weight, and the amount of the Group VIIIA metal is the total weight of the catalyst. When it is 100% by weight, it is preferably 0.01 to 5% by weight. The Group VIIIA metal is preferably platinum.

As the zeolite, silicalite or borosilicate is preferable, and one having an MFI structure is more preferable. A more preferable zeolite carrier is a silicate obtained by removing at least a part of boron atoms from MFI-type borosilicate, and the boron atom remaining rate in the silicate is 80% or less of the total amount of boron atoms in MFI-type borosilicate. Some are particularly preferred.

According to the present invention, the volatilization of zinc from the dehydrogenation catalyst can be effectively suppressed by a very simple method, and as a result, the high activity of the dehydrogenation catalyst can be obtained over a long period of time. It is possible to produce predominantly unsaturated hydrocarbons, ie olefins or dienes.

The propylene yield of the case where zinc oxide was filled upstream of the gas flow in the reaction tube with respect to the catalyst layer (Example 1, plotted with ◯) and not filled (Comparative Example 1, plotted with ●). It is a figure which shows the difference of a time-dependent change.

Details of the present invention will be described below.
In the method for producing unsaturated hydrocarbons according to the present invention (production method (1)), a raw material-containing gas (1) containing hydrocarbons is brought into contact with metal zinc and / or a zinc compound, and then one of the active ingredients. And a step of producing an unsaturated hydrocarbon by bringing the hydrocarbon into contact with a dehydrogenation catalyst containing zinc.

In another aspect of the present invention, an unsaturated hydrocarbon production method (production method (2)) according to the present invention uses a raw material-containing gas (2) containing hydrocarbon and zinc vapor as one of the active components. It includes a step of producing an unsaturated hydrocarbon by contacting with a dehydrogenation catalyst containing zinc to perform a dehydrogenation reaction of the hydrocarbon.
The following description applies to both the manufacturing method (1) and the manufacturing method (2) unless otherwise specified.

The reaction temperature range during the dehydrogenation reaction is preferably 300 to 800 ° C., more preferably 400 to 700 ° C., and particularly preferably 450 to 650 ° C. When the reaction temperature is equal to or higher than the lower limit, the hydrocarbon as a raw material is converted to an unsaturated hydrocarbon at a high equilibrium conversion rate, so that the unsaturated hydrocarbon is produced in a high yield with a single pass. Further, when the reaction temperature is not more than the above upper limit value, the coking speed is not increased, and the activity deterioration of the catalyst can be suppressed.

The range of the reaction pressure is preferably 0.01 to 1 MPa, more preferably 0.01 to 0.5 MPa. The lower the reaction pressure, the higher the equilibrium conversion rate of the raw material hydrocarbon, and the higher the yield of unsaturated hydrocarbon in one pass.

Since the production method of the present invention is carried out in the gas phase, the reaction is preferably carried out in a continuous reaction apparatus. At this time, the amount of catalyst used is simply and appropriately expressed by the weight hourly space velocity WHSV (the weight of the feedstock hydrocarbon per unit weight of catalyst and unit time). Range of WHSV in the present invention is not particularly limited, preferably 0.01 ~ 50h ^-1, more preferably from 0.1 ~ 20h ^-1.

In the production method (2), the present invention is characterized in that a raw material-containing gas containing zinc vapor is brought into contact with a catalyst containing zinc as one of active components. By bringing zinc vapor into contact with the catalyst, the volatilization of zinc from the catalyst is suppressed, so that the catalyst can exhibit stable performance over a long period of time. The partial pressure of the zinc vapor contained in the raw material-containing gas in contact with the catalyst is equal to or lower than the vapor pressure of zinc at the reaction temperature, and the concentration (based on volume) of the zinc vapor contained in the raw material-containing gas exceeds 0%. Preferably, it is 0.01% or more, More preferably, it is 0.05% or more.

Examples of the source of zinc vapor include metal zinc, zinc oxide, zinc nitrate, zinc chloride, zinc acetate, zinc aluminate and the like, and since zinc vapor is easily generated, metal zinc and / or zinc oxide is used. preferable.

The source of zinc vapor is heated to generate zinc vapor having a predetermined partial pressure, but the temperature range is preferably 300 ° C. or higher and the reaction temperature or lower, more preferably 400 ° C. or higher and the reaction temperature or lower. Particularly preferably, it is 450 ° C. or higher and the reaction temperature or lower.

There is no particular limitation on the method for supplying zinc vapor to the raw material-containing gas. For example, the metallic zinc and / or zinc compound is heated to a predetermined temperature in a chamber separate from the reactor (that is, the vessel for performing the hydrocarbon dehydrogenation reaction). Then, by passing a mixed gas consisting of a hydrocarbon gas as a raw material and an inert gas optionally used, zinc vapor corresponding to the maximum vapor pressure and a hydrocarbon gas as a raw material and an inert gas You may include in the mixed gas which consists of. Further, a catalyst layer containing the catalyst is formed in the reaction tube, and a layer of zinc oxide or zinc aluminate is provided on the upstream side of the gas flow in the reaction tube with respect to the catalyst layer, and this layer is formed as a reducing gas (for example, , Hydrogen gas) is heated in the presence of this gas to generate zinc vapor from this layer, including the raw material hydrocarbon gas, optionally used inert gas, and optionally unreacted reducing gas. Immediately before the mixed gas comes into contact with the catalyst layer, zinc gas corresponding to a maximum vapor pressure may be contained in the mixed gas.

The supply of zinc vapor may be continuous or intermittent, but in the case of intermittent supply, it is necessary to provide a chamber separate from the reactor.
In the present invention, hydrocarbons that are converted to unsaturated hydrocarbons by dehydrogenation are fed to the reactor. The unsaturated hydrocarbon produced in the present invention is preferably an olefin (unsaturated hydrocarbon in which one double bond exists in one molecule) and a diene (one double bond in one molecule) from the viewpoint of industrial usefulness. Unsaturated hydrocarbons present in the two). That is, the method for producing unsaturated hydrocarbons of the present invention is preferably a method for producing olefins or dienes.

Particularly preferred compounds as the hydrocarbon as the raw material are propane, n-butane, isobutane, 1-butene, 2-butene and mixtures thereof, and particularly preferred compounds as the unsaturated hydrocarbon are propylene, 1-butene, 2 -Butene, isobutene, 1,3-butadiene and mixtures thereof. A mixture of 1-butene and 2-butene is usually referred to as n-butene.

The raw material hydrocarbon gas may be supplied to the reactor together with other gases that do not impair the effects of the present invention. Examples of the other gases include water vapor, nitrogen gas, carbon dioxide gas, hydrogen gas, and methane gas. Can be mentioned. Among these, water vapor is particularly preferable from the viewpoint of extending the life of the dehydrogenation catalyst. Moreover, the remainder of the hydrogen gas used in order to generate zinc vapor | steam from zinc oxide may be supplied as other gas. The mixing method and mixing ratio of the hydrocarbon gas and the other gas are not particularly limited.

The reaction format used in the present invention is not particularly limited, and a known method can be employed, and examples thereof include a fixed bed, a moving bed, and a fluidized bed. From the viewpoint of ease of process design, a fixed bed type is particularly preferable.

In the present invention, a dehydrogenation catalyst containing zinc is used as one of the active components, preferably a catalyst using zeolite as a carrier and carrying zinc and a Group VIIIA metal as the active components.

Zinc and Group VIIIA metals can be supported on the zeolite using, for example, metal compounds such as the corresponding metal nitrates, metal chlorides or metal complexes. The loading on zeolite can be carried out by a known method such as an ion exchange method or an impregnation method, and the order of loading is not particularly limited.

Examples of the zinc compound include zinc nitrate, zinc chloride, and zinc acetate. Examples of the Group VIIIA metal compound include chloroplatinic acid, tetraammineplatinum chloride, tetraammineplatinum hydroxide, and tetraammineplatinum nitrate.

The range of the amount of zinc contained in the dehydrogenation catalyst is preferably from 0.01 to 15% by weight, more preferably from 0.05 to 15% by weight as the ratio of the weight of zinc metal atoms to the weight of the whole catalyst (100% by weight). 5% by weight, particularly preferably 0.1 to 3% by weight.

The range of the amount of the Group VIIIA metal contained in the dehydrogenation catalyst is preferably 0.01 to 5% by weight, more preferably as a ratio of the weight of the Group VIIIA metal atom to the total weight (100% by weight) of the catalyst. Is 0.05 to 3% by weight, particularly preferably 0.1 to 1.5% by weight.

The ratio of zinc to the Group VIIIA metal is usually 0.5 or more, preferably 0.5 to 50, more preferably 1 to 30, in terms of molar ratio (number of moles of Zn / number of moles of Group VIIIA metal). Preferably it is 1-20.

The Group VIIIA metal is an old IUPAC system notation, which is a Group 8-10 metal in the IUPAC system. Examples of the Group VIIIA metal include platinum, palladium, ruthenium, iridium, rhodium, and nickel. Among these, platinum is preferable from the viewpoint of catalytic activity.

In an example of the method for producing the dehydrogenation catalyst, the zinc compound and optionally the Group VIIIA metal compound are supported on zeolite, followed by drying and calcination. The drying conditions are not particularly limited, but the drying is usually performed at 80 to 150 ° C. for a predetermined time. The firing conditions are not particularly limited, but the firing is usually performed at 400 to 600 ° C. for a predetermined time. The atmosphere during firing is not particularly limited, but usually drying and firing are carried out under air circulation.

The above-mentioned zeolite is a name used as a general term for crystalline porous aluminosilicate, and is classified by a structure code according to the topology. For each structure code, information about structure, composition, crystallographic data is known (for example, Atlas of Zeolite Structure Types, 4th Ed., Elsevier 1996, and Collection of Simulated XRD Powder Pattern 19). ). In addition, as a compound other than aluminosilicate having the same crystal structure, silicalite not containing aluminum, metallosilicate containing iron, gallium, titanium, etc. instead of aluminum are also included in zeolite (for example, the science of zeolite And engineering, Kodansha Scientific).

In the present invention, silicalite containing no aluminum or borosilicate which is a metallosilicate containing boron instead of aluminum is preferably used as a catalyst carrier.

The aluminum content in the silicalite or borosilicate used in the present invention is not particularly limited, but the silica / alumina molar ratio (number of moles of SiO ₂ / number of moles of Al ₂ O ₃ ) in these zeolites is 100 or more. Is more preferably 500 or more, particularly preferably 1000 or more, and most preferably 2000 or more. When the silica / alumina molar ratio is 100 or more, side reactions such as oligomerization that proceeds on acid sites caused by aluminum are suppressed. If the silica / alumina molar ratio is 2000 or more, such side reactions can be more effectively suppressed.

The boron content in the borosilicate is not particularly limited, but is preferably 100 to 30000 ppm, more preferably 500 to 10000 ppm, and particularly preferably 1000 to 80000 ppm.

The content of alkali metal and alkaline earth metal in silicalite or borosilicate is not particularly limited, but it is preferable that these metals are not substantially present. “Substantially absent” means that the content of alkali metal and alkaline earth metal in silicalite or borosilicate is 300 ppm or less, respectively.

Furthermore, it is preferable that the silicalite and the borosilicate have an MFI structure.
A borosilicate having an MFI structure (hereinafter also referred to as “MFI-type borosilicate”) may be used as a carrier as it is, but a silicate obtained by removing at least a part of boron atoms from the MFI-type borosilicate is used as a carrier. It is preferable to use it.

The boron atom remaining rate in the silicate after removing at least a part of boron atoms from the MFI-type borosilicate is preferably 80% or less of the total amount of boron atoms in the borosilicate, and is 50% or less. Is more preferably 30% or less, and most preferably 20% or less.

The boron atom residual ratio is calculated by comparing the boron atom content in the borosilicate before removing the boron atom and the boron atom content in the silicate after removing the boron atom. The method for removing at least a part of boron atoms from the borosilicate is not limited, and a known method such as a method of treating with an aqueous solution of an inorganic acid or an organic acid is employed.

The catalyst charged in the reactor may be in the form of a powder or a molded body. There is no restriction | limiting about a shaping | molding method, Well-known methods, such as extrusion molding, tableting shaping | molding, and coating shaping | molding, are employ | adopted.

A pretreatment for activating the catalyst may be performed after the catalyst is charged into the reactor and before the start of the reaction. In the pretreatment, the catalyst is usually a reducing gas such as hydrogen or carbon monoxide. Contact. These reducing gases may be used without being diluted, or may be appropriately diluted with the above-described inert gas.

When a certain time has elapsed from the start of the reaction and a decrease in the catalyst activity is confirmed, the reaction may be stopped and the catalyst may be reactivated by a method called regeneration treatment. The method is not particularly limited, but usually a method of burning and removing heavy hydrocarbons called coke deposited on the catalyst surface by bringing a gas containing oxygen into contact with the catalyst at a predetermined temperature.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
(Catalyst preparation 1)
10 g of MFI-type borosilicate containing 3200 ppm of boron atom was stirred in 200 ml of 1N nitric acid aqueous solution at 80 ° C. for 2 hours, and then filtered to separate into a cake and a filtrate. Furthermore, the operation of stirring the filtered cake in 200 ml of 1N nitric acid aqueous solution at 80 ° C. for 2 hours and then filtering to separate the cake and the filtrate was repeated twice, and then the filtered cake was used. Washed with distilled water until the washed solution was neutral. The washed cake was dried for 3 hours in a static electric furnace in which air was circulated and maintained at 120 ° C., and then calcined at 500 ° C. for 4 hours. A silicate from which part was removed was obtained. The amount of boron atoms in the obtained silicate was 260 ppm, and the residual ratio of boron atoms at this time was 8%.

(Catalyst preparation 2)
To 2 g of the silicate obtained in Catalyst Preparation 1, 0.66 g of an aqueous solution containing 0.058 g of zinc nitrate hexahydrate was added and impregnated with zinc ions by the incipient-wetness method. The silicate impregnated with zinc ions was dried for 3 hours in a static electric furnace maintained at 120 ° C. through which air was circulated, and then baked at 500 ° C. for 4 hours to form a silicate on which zinc was supported. Prepared.

(Catalyst preparation 3)
Add 0.375 g of an aqueous solution containing 0.0127 g of chloroplatinic acid hexahydrate to 1.5 g of the zinc-supported silicate obtained in Catalyst Preparation 2, and impregnate it with platinum ions by the incipient-wetness method. It was. The silicate impregnated with platinum ions was dried for 3 hours in a static electric furnace in which air was circulated and maintained at 120 ° C., followed by firing at 500 ° C. for 4 hours to support platinum and zinc. Silicate catalyst powder was obtained. This silicate catalyst had a platinum loading of 0.32 wt% and a zinc loading of 0.64 wt%.

[Example 1]
An SUS tube equipped with an inner tube of alumina with an inner diameter of 6 mm was filled with 0.2 g of the silicate catalyst carrying platinum and zinc obtained in Catalyst Preparation 3, and then oxidized upstream of the catalyst with silica wool in between. A reaction tube was manufactured by charging 0.1 g of zinc (manufactured by Sigma-Aldrich), filling alumina balls before and after them, and fixing the catalyst and zinc oxide. The catalyst was pretreated by flowing a mixed gas consisting of 20 sccm of hydrogen and 0.064 g / min of water vapor at 600 ° C. and atmospheric pressure for 2 hours, and then the reaction tube was pretreated with 2.1 sccm of hydrogen, 13.55 sccm of propane, and 0. The propane dehydrogenation reaction was started by feeding 022 g / min. Moreover, the reaction temperature was raised to 650 degreeC with the start of reaction.
The catalyst showed stable activity over a long period of time, with a propylene yield of 60% over about 120 hours.

[Comparative Example 1]
A reaction tube was produced in the same manner as in Example 1 except that zinc oxide was not charged, and propane dehydrogenation reaction was started under the same pretreatment conditions and reaction conditions as in Example 1. The catalyst showed a propylene yield of 60% over about 60 hours.

[Comparative Example 2]
A reaction tube was manufactured in the same manner as in Example 1 except that the silicate catalyst was not charged. As in Example 1, the reaction tube was charged with 20 sccm of hydrogen and 0.064 g / min of water vapor at 600 ° C. and normal pressure. After flowing the mixed gas for 2 hours, 2.1 sccm of hydrogen, 13.55 sccm of propane, and 0.022 g / min of water vapor were supplied at 650 ° C. Zinc oxide did not show any catalytic activity in the propane dehydrogenation reaction.
From the above results, it is clear that the zinc oxide itself charged upstream of the catalyst has no catalytic activity, while the presence of zinc oxide exhibits a high activity over a long period of time.

[Reference example]
A reaction tube was manufactured in the same manner as in Comparative Example 2 except that a quartz tube that had been processed to fix the catalyst was used instead of the SUS tube that was fitted with an alumina intubation tube, and the alumina balls were not filled. In the same manner as in Comparative Example 2, after flowing a mixed gas composed of hydrogen at 20 ° C. and water vapor at 0.064 g / min at 600 ° C. and normal pressure for 2 hours, 650 ° C. at 2.1 sccm of hydrogen and propane 13.55 sccm and water vapor 0.022 g / min were fed. As in Comparative Example 2, zinc oxide did not show any catalytic activity in the propane dehydrogenation reaction, but a silvery and band-like film was formed at the bottom of the quartz tube after the reaction. As a result of analyzing the solution after dissolving this film with dilute nitric acid by ICP (inductively coupled plasma), it was confirmed that the silver-colored and band-shaped film was zinc.

From the above results, it is clear that at least a part of the zinc oxide was reduced during the pretreatment and during the reaction to become metallic zinc, from which zinc vapor was generated and moved in the gas phase. It is also clear that the partial pressure of zinc vapor at this time is equal to or lower than the vapor pressure of zinc at 650 ° C., which is the reaction temperature.

Claims (19)

1. A hydrocarbon-containing feed gas (1) is contacted with zinc metal or a zinc compound or both and then contacted with a dehydrogenation catalyst containing zinc as one of the active components to effect dehydrogenation of the hydrocarbon. A method for producing unsaturated hydrocarbon, comprising a step of producing unsaturated hydrocarbon.
2. The method for producing an unsaturated hydrocarbon according to claim 1, wherein the raw material-containing gas (1) further contains water vapor.
3. The method for producing an unsaturated hydrocarbon according to claim 1 or 2, wherein the raw material-containing gas (1) further contains hydrogen.
4. A raw material-containing gas (1) containing hydrocarbons is brought into contact with metal zinc or a zinc compound or both to obtain a raw material-containing gas (2) containing hydrocarbons and zinc vapor, and the raw material-containing gas (2) is The method for producing an unsaturated hydrocarbon according to claim 1, comprising a step of producing an unsaturated hydrocarbon by contacting with a dehydrogenation catalyst containing zinc as one of active components to perform a dehydrogenation reaction of the hydrocarbon. .
5. The method for producing an unsaturated hydrocarbon according to claim 4, wherein a partial pressure of zinc vapor contained in the raw material-containing gas (2) is equal to or lower than a vapor pressure of zinc at a reaction temperature of the dehydrogenation reaction.
6. The method for producing an unsaturated hydrocarbon according to claim 4 or 5, wherein the raw material-containing gas (2) further contains water vapor.
7. The method for producing an unsaturated hydrocarbon according to any one of claims 4 to 6, wherein the raw material-containing gas (2) further contains hydrogen.
8. The method for producing an unsaturated hydrocarbon according to any one of claims 1 to 7, wherein a reaction temperature in the dehydrogenation reaction is in a range of 300 to 800 ° C and a reaction pressure is in a range of 0.01 to 1 MPa.
9. The method for producing an unsaturated hydrocarbon according to any one of claims 1 to 8, wherein the zinc compound is zinc oxide.
10. The method for producing an unsaturated hydrocarbon according to any one of claims 1 to 9, wherein the hydrocarbon is at least one hydrocarbon selected from propane, n-butane and isobutane.
11. The method for producing an unsaturated hydrocarbon according to any one of claims 1 to 9, wherein the hydrocarbon is n-butene.
12. The method for producing an unsaturated hydrocarbon according to any one of claims 1 to 11, wherein the dehydrogenation catalyst is a catalyst using zeolite as a carrier and carrying zinc and a Group VIIIA metal as active components.
13. The method for producing an unsaturated hydrocarbon according to claim 12, wherein the amount of zinc contained in the dehydrogenation catalyst is 0.01 to 15% by weight when the weight of the whole catalyst is 100% by weight.
14. The production of an unsaturated hydrocarbon according to claim 12 or 13, wherein the amount of the Group VIIIA metal contained in the dehydrogenation catalyst is 0.01 to 5% by weight, where the total weight of the catalyst is 100% by weight. Method.
15. The method for producing an unsaturated hydrocarbon according to any one of claims 12 to 14, wherein the Group VIIIA metal is platinum.
16. The method for producing an unsaturated hydrocarbon according to any one of claims 12 to 15, wherein the zeolite is silicalite or borosilicate.
17. The method for producing an unsaturated hydrocarbon according to claim 16, wherein the silicalite or the borosilicate has an MFI structure.
18. The method for producing an unsaturated hydrocarbon according to any one of claims 12 to 15, wherein the zeolite is a silicate obtained by removing at least a part of boron atoms from an MFI-type borosilicate.
19. The method for producing an unsaturated hydrocarbon according to claim 18, wherein a residual ratio of boron atoms in the silicate is 80% or less of a total amount of boron atoms in the MFI-type borosilicate.

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