KR102639656B1 - A supported catalyst for oxidative dehydrogenation of alkane and method for preparing alkene using the same - Google Patents

Abstract

The present invention relates to a supported catalyst for the dehydrogenation reaction of alkanes and a method for producing alkenes using the same. More specifically, in the process of producing propene by the dehydrogenation reaction of propane, the catalytic activity is high and the pro It relates to a supported catalyst with high selectivity for pen and a method for producing propene using the same.

Description

Supported catalyst for dehydrogenation reaction of alkanes and method for producing alkenes using the same {A SUPPORTED CATALYST FOR OXIDATIVE DEHYDROGENATION OF ALKANE AND METHOD FOR PREPARING ALKENE USING THE SAME}

The present invention relates to a supported catalyst for the dehydrogenation reaction of alkanes and a method for producing alkenes using the same.

Alkene compounds such as ethene (ethylene), propene (propylene), butene, etc., that is, olefin compounds, are widely used as basic materials for the synthesis of other compounds or polymers in the petrochemical industry.

For example, ethylene is an olefin compound with the simplest structure and is used as a basic monomer for the synthesis of polyethylene and other polymers, and is also used for welding and fruit ripening.

Propylene, along with ethylene, is the most basic substance used as a standard in the petrochemical industry. It has a methyl group and an ethylenically unsaturated bond, so it can be converted into various chemical substances. Representatively, it is mainly used in the production of polypropylene, a thermoplastic plastic, and is also used as a raw material for acrylonitrile, propylene oxide, epoxy resin, oxo alcohol, and isopropyl alcohol.

In the case of butene, it is used as a copolymer monomer with ethylene and propylene, or in the production of butadiene, another major industrial raw material.

Generally, these olefin compounds are produced as by-products during the refining process of crude oil or obtained through the thermal decomposition process of naphtha, but recently, in order to meet the large demand in the petrochemical industry, they are also produced through the dehydrogenation process of low-grade hydrocarbons using catalysts. It is being produced.

In particular, in the case of propylene, demand is increasing as its use as a vehicle or electrical material material is rapidly increasing. Since the existing crude oil refining process or naphtha cracking process is mainly focused on the production of ethylene, the increase in supply of propylene is not possible. There are restrictions, and technologies for diversifying propylene supply are attracting attention.

The dehydrogenation reaction of alkanes is the main reaction that can produce these olefin compounds, and can be carried out under high temperature and low pressure conditions and in the presence of a noble metal catalyst or transition metal catalyst.

In the case of noble metal catalysts, the reaction is known to proceed by a direct dehydrogenation mechanism in which hydrogen is adsorbed at the active site, and in the case of transition metal oxides, the reaction is known to proceed by a partial oxidation mechanism of the lattice oxygen of the catalyst.

As noble metal catalysts, catalysts such as platinum are known, and as transition metal catalysts, catalysts containing chromium oxide or vanadium oxide as the active phase on an alumina carrier are known.

However, there is a problem in that it is difficult to obtain sufficient yield of propylene with a single metal alone without an oxidizing agent, and the catalyst activity is easily reduced due to the low surface area, so while showing high activity in the reaction, it shows high selectivity for a specific product. Catalytic research is needed.

The present specification seeks to provide a catalyst for the dehydrogenation reaction of alkanes, which shows high activity in the dehydrogenation reaction of alkanes and high selectivity for specific alkenes.

Additionally, the present specification seeks to provide a method for producing alkenes using the catalyst.

The present invention includes a carrier and a catalytically active metal supported on the carrier; The catalytically active metal is one or more selected from the group consisting of i) platinum (Pt), and ii) tin (Sn), zinc (Zn), cerium (Ce), iridium (Ir), and gallium (Ga). Contains; The carrier includes alumina on kappa; The object is to provide a supported catalyst for the dehydrogenation reaction of alkanes having 2 to 6 carbon atoms.

The supported catalyst for the dehydrogenation reaction of an alkane having 2 to 6 carbon atoms may include about 10 to about 500 parts by weight of the second metal based on 100 parts by weight of the first metal, and more preferably may include about 50 to about 300 parts by weight of the second metal, or about 80 to about 250 parts by weight, based on about 100 parts by weight of the first metal.

In addition, the supported catalyst for the dehydrogenation reaction of an alkane having 2 to 6 carbon atoms contains about 0.01 to about 10 parts by weight of the second metal, preferably about 0.1 to about 0.1 to about 100 parts by weight of the carrier. It may contain 5 parts by weight, or about 0.5 to about 2 parts by weight.

In addition, the supported catalyst for the dehydrogenation reaction of an alkane having 2 to 6 carbon atoms contains about 0.01 to about 10 parts by weight of the first metal, preferably about 0.05 to about 0.05 to about 100 parts by weight of the carrier. It may contain 5 parts by weight, or about 0.1 to about 2 parts by weight.

And, the catalytically active metal may further include a Group 1 metal. At this time, the Group 1 metal may include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs).

In this case, the Group 1 metal may be included in an amount of about 10 to about 200 parts by weight, or about 50 to about 150 parts by weight, based on 100 parts by weight of the first metal.

In addition, the kappa phase alumina may have a BET surface area of about 50 to about 200 m ² /g, preferably about 100 to about 170 m ² /g, or about 120 to about 150 m ² /g.

In addition, the kappa phase alumina may have an average pore diameter of about 5 to about 20 nm, preferably about 10 to about 15 nm, and a total pore volume of about 0.2 to 0.7 cm ³ /g, preferably about It may be 0.3 to about 0.5 cm ³ /g.

In addition, the kappa phase alumina may have a functional group content on its surface of about 0.5 to 0.8 mmol/g, preferably about 0.6 to about 0.7 mmol/g, or about 0.63 to about 0.68 mmol/g.

Meanwhile, the present invention provides a method for producing an alkene having 2 to 6 carbon atoms, comprising the step of carrying out a dehydrogenation reaction of an alkane having 2 to 6 carbon atoms in the presence of any of the catalysts described above. We would like to provide

At this time, the alkane having 2 to 6 carbon atoms is propane, butane, pentane, and hexane. At least one selected from the group consisting of hexane; The alkene having 2 to 6 carbon atoms may be one or more selected from the group consisting of propene, butane, pentene, and hexane, and more preferably, the alkene An alkane having 2 to 6 carbon atoms may be propane, and an alkene having 2 to 6 carbon atoms may be propene.

And, specifically, the method for producing an alkene having 2 to 6 carbon atoms includes activating the catalyst using an active gas; and contacting the activated catalyst with an alkane having 2 to 6 carbon atoms.

In the present invention, terms such as first and second are used to describe various components, and the terms are used only for the purpose of distinguishing one component from another component.

Additionally, the terminology used herein is only used to describe exemplary embodiments and is not intended to limit the invention.

Singular expressions include plural expressions unless the context clearly dictates otherwise.

In this specification, terms such as “comprise,” “comprise,” or “have” are used to describe implemented features, numbers, steps, components, or combinations thereof, and include one or more other features, numbers, or steps. , does not exclude the possibility of components, combinations or additions thereof.

Additionally, in this specification, when each layer or element is referred to as being formed “on” or “on” the respective layers or elements, it means that each layer or element is formed directly on the respective layers or elements, or other This means that layers or elements can be additionally formed between each layer, on the object, or on the substrate.

Since the present invention can be subject to various changes and can take various forms, specific embodiments will be illustrated and described in detail below. However, this does not limit the present invention to the specific disclosed form, and should be understood to include all changes, equivalents, and substitutes included in the spirit and technical scope of the present invention.

In this specification, the dehydrogenation reaction of an alkane having 2 to 6 carbon atoms means that hydrogen is adsorbed to the active site of the catalyst, and two different hydrogens bonded to adjacent carbons of the alkane are removed. This refers to a direct dehydrogenation reaction in which a double bond is formed between adjacent carbons, and is distinguished from an oxidative dehydrogenation reaction that occurs through a partial oxidation mechanism of oxygen located in the lattice of the catalyst.

This direct dehydrogenation reaction can be briefly expressed by the reaction mechanism below.

In the above reaction formula, R1 and R2 may each independently be the same or different from each other, hydrogen, or alkyl having 1 to 4 carbon atoms.

Hereinafter, the present invention will be described in detail.

According to one aspect of the present invention, it includes a carrier and a catalytically active metal supported on the carrier; The catalytically active metal is one or more selected from the group consisting of i) platinum (Pt), and ii) tin (Sn), zinc (Zn), cerium (Ce), iridium (Ir), and gallium (Ga). Contains; The carrier includes alumina on kappa; A supported catalyst for the dehydrogenation reaction of an alkane having 2 to 6 carbon atoms is provided.

As described above, the direct dehydrogenation reaction of an alkane is a reaction that removes hydrogen atoms bonded to adjacent carbons from an alkane to produce an olefin having a carbon double bond.

This direct dehydrogenation reaction is thermodynamically unfavorable because it is a highly endothermic reaction, although the reaction mechanism itself is very simple. Therefore, in order to increase the yield of alkenes, very high temperature reaction conditions are required, generally, at temperature conditions of about 500 to about 800 ° C. and pressure conditions of about 0.5 to about 2 atm, metals such as platinum It proceeds in the presence of a catalyst.

However, when using a catalyst and increasing the temperature to increase the conversion rate, the carbon-carbon bond of the alkane reactant is broken, and as hydrogen is added, side reactions such as decomposition into smaller alkanes increase, and the catalyst or There is a problem in that by-products such as coke or tar are rapidly deposited on the carrier, and the activity of the catalyst is instantly reduced.

The inventors of the present invention have found that when a metal catalyst of a specific composition is used while supported on a specific carrier, the activity for the dehydrogenation reaction of alkanes is very high and the selectivity for specific olefins is very high, preventing the generation of by-products. The present invention was completed after discovering that catalytic activity can be suppressed and thus high catalytic activity can be stably maintained.

According to one embodiment of the present invention, a supported catalyst for the dehydrogenation reaction of an alkane having 2 to 6 carbon atoms includes a carrier and a catalytically active metal supported on the carrier; The catalytically active metal is one or more selected from the group consisting of i) platinum (Pt), and ii) tin (Sn), zinc (Zn), cerium (Ce), iridium (Ir), and gallium (Ga). Contains; The carrier includes kappa phase alumina, κ-phase alumina, or κ-alumina.

At this time, the supported catalyst for the dehydrogenation reaction of an alkane having 2 to 6 carbon atoms may include about 10 to about 500 parts by weight of the second metal based on 100 parts by weight of the first metal, More preferably, it may include about 50 to about 300 parts by weight, or about 80 to about 250 parts by weight, of the second metal, based on about 100 parts by weight of the first metal.

In addition, the supported catalyst for the dehydrogenation reaction of an alkane having 2 to 6 carbon atoms contains about 0.01 to about 10 parts by weight of the second metal, preferably about 0.1 to about 0.1 to about 100 parts by weight of the carrier. It may contain 5 parts by weight, or about 0.5 to about 2 parts by weight.

In addition, the supported catalyst for the dehydrogenation reaction of an alkane having 2 to 6 carbon atoms contains about 0.01 to about 10 parts by weight of the first metal, preferably about 0.05 to about 0.05 to about 100 parts by weight of the carrier. It may contain 5 parts by weight, or about 0.1 to about 2 parts by weight.

Due to the above relative amounts, it may be more preferable for the catalytically active metal in the catalyst of the present invention to have the following compositional form.

X(M2)-Y(M1)/Al ₂ O ₃

In the above composition formula, M2 is the second metal, M1 is the first metal,

X and Y are the ratio of each metal atom or metal atom group, where X is 0.1 or more, or about 1 or more, or about 3 or more, or 5 or less, or about 4 or less, or about 3.5 or less, and Y is 1.0. .

Due to the composition described above, the catalyst according to an example of the present invention can exhibit high activity for the dehydrogenation reaction of alkanes and at the same time have high selectivity for specific alkenes.

In the catalyst composition, the first metal may mainly serve to provide an active site for the above-described reaction.

In addition, the second metal may weaken the interaction between the second metal and the alkene, which is a product of the reaction, thereby promoting removal of the product from the catalytic active site and playing a role in suppressing side reactions. It can act as a kind of co-catalyst that prevents a decrease in catalytic activity due to sintering of the first metal. The role of this second metal can be especially maximized when the second metal becomes ionic by combining with the carrier or the first metal on the carrier.

From this point of view, if the ratio of the second metal exceeds the above range and becomes too high, a problem may occur in which the conversion rate is reduced by covering the active sites of the first metal, that is, platinum (Pt), and the ions of the first metal may be converted into metal. There is a high probability that it exists in its own state, so the above-mentioned effects may be reduced.

On the other hand, if the ratio of the first metal, that is, platinum (Pt), exceeds the above range and becomes too high, sintering of the metal occurs and coke is easily generated, which causes the problem of reduced catalytic activity. You can.

And, the catalytically active metal may further include a Group 1 metal. At this time, the Group 1 metal may include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs).

Alumina, that is, Al ₂ O ₃ , used as a carrier in the present invention, is neutral as a material itself, but acid points exist on its surface, and these acid points serve as active points for side reactions in the dehydrogenation reaction of alkane. This action can promote the formation of by-products.

The above-described Group 1 metal can bind to acid sites on the alumina surface to suppress side reactions, thereby reducing deposition of by-products, coke, etc.

In this case, the Group 1 metal may be included in an amount of about 10 to about 200 parts by weight, or about 50 to about 150 parts by weight, based on 100 parts by weight of the first metal.

If the content of the Group 1 metal is too small, it may not be sufficient to achieve the above-described effect, and if the content of the Group 1 metal is too high, the problem of lowering the activity of the dehydrogenation reaction of the alkane may occur.

Meanwhile, in the supported catalyst for the dehydrogenation reaction of an alkane having 2 to 6 carbon atoms according to an embodiment of the present invention, kappa phase alumina, κ-phase alumina, or κ-alumina is used as a carrier. ) is used.

Alumina, depending on its crystalline structure, has alpha phase (α phase, chi phase), eta phase (η phase, eta phase), and delta phase (δ phase). , delta phase, kappa phase (κ phase, kappa phase), theta phase (θ phase, theta phase), gamma phase (γ phase, gamma phase), rho phase (ρ phase, rho phase), etc. It can be, and generally, alpha-phase or gamma-phase alumina is used as a catalyst carrier.

However, in the case of such alpha-phase or gamma-phase alumina, a relatively large number of acid points are distributed on the surface, and these acid points act as active points for side reactions in the dehydrogenation reaction of alkanes, as described above. Deposition of by-products is accelerated, and deactivation of the catalyst progresses very quickly.

In addition, if Group 1 metals are used to solve this acid point problem, the amount of Group 1 metals used may excessively increase, which may cause problems in terms of cost. In addition, a decrease in catalytic activity points may result in Al. There is a problem in that the activity for the dehydrogenation reaction of cane may be reduced and the selectivity for specific olefins is greatly reduced.

However, compared to other forms, alumina in the kappa phase has a relatively large surface area, but the number of acid sites distributed on the surface is relatively small, so when it is used as a carrier, its catalytic activity for the dehydrogenation reaction of alkanes is very high. is maintained high, side reactions are relatively suppressed, and selectivity for specific olefins can also be maintained high.

Such kappa-phase alumina can be formed from gibbsite or chi-phase alumina by heat treatment reaction. Specifically, gibbsite is stable below about 150°C, but is stable at temperatures above about 250°C. , the alumina in the chi phase is replaced by the alumina in the chi phase, which can also remain in a stable form at temperatures from about 250 to about 650° C., but at temperatures above about 700 or about 750° C., it is replaced by the alumina in the kappa phase. (replaced) In the case of alumina in the kappa phase, its form can be stably maintained at a temperature of about 750 to about 1000°C.

This kappa phase alumina is known to have a hexagonal crystal structure, and in particular, has about 28 unit molecules per unit cell, which, compared to alumina of other phases, per unit cell. It contains the largest number of unit molecules.

Due to these molecular structural characteristics, although kappa-phase alumina has a high specific surface area, only a relatively small amount of acid sites are distributed on its surface. When a catalytically active metal is supported on kappa-phase alumina, the catalytically active metal is While the catalytic activity for the dehydrogenation reaction of alkanes can be maintained very high, side reactions can be effectively suppressed.

In this respect, the BET surface area value of the kappa phase alumina is specifically about 50 to about 200 m ² /g, preferably about 100 to about 170 m ² /g, or about 120 to about 150 m ² /g. It can be.

If the BET surface area value is too small, sufficient active sites may not be provided to the catalytically active metal, which may result in a decrease in activity for the reaction.

In addition, the kappa phase alumina may have an average pore diameter of about 5 to about 20 nm, preferably about 10 to about 15 nm, and a total pore volume of about 0.2 to 0.7 cm ³ /g, preferably about It may be 0.3 to about 0.5 cm ³ /g.

In addition, the kappa phase alumina may have a functional group content on its surface of about 0.5 to 0.8 mmol/g, preferably about 0.6 to about 0.7 mmol/g, or about 0.63 to about 0.68 mmol/g.

Due to the above-described pore characteristics, the kappa-phase alumina may have a large BET surface area and a large total pore volume compared to the average pore diameter, but has the characteristic of having a relatively small number of functional groups, that is, acid points, distributed on the surface. .

Therefore, when kappa-phase alumina, which has these characteristics, is used as a catalyst carrier, the catalytic activity for the dehydrogenation reaction of alkanes is maintained very high, side reactions are relatively suppressed, and selectivity for specific olefins is also maintained high. It can be.

The supported catalyst as described above can be prepared by a sequential impregnation method, a co-precipitation method, or a sol- It can be manufactured by a method generally used when supporting a metal catalyst on a carrier, such as the gel method (sol-gel method).

Salts of the first metal, that is, platinum (Pt), that can be used at this time include halogenates of platinum, including PtBr ₂ , PtCl ₂ , PtCl ₄ , PtI _{2 ,} etc.; Hydrohalides of platinum, including H ₂ PtBr ₆ (xH ₂ O), H ₂ PtCl ₆ (xH ₂ O), hydrogen hydroxides of platinum, including H ₂ Pt(OH) ₆ , or Pt. and ammonia chloride of platinum, including (NH ₃ ) ₂ Cl ₄ and Pt(NH ₃ ) ₂ Cl ₂ .

In addition, the salt of the second metal includes halides containing the above-mentioned second metal and Cl, Br, I, etc., sulfate salt of the second metal, carbonate salt of the second metal, and nitrate salt of the second metal. , hydroxide salts of the second metal, or organic acid salts of the second metal, etc. can be used.

These precursors may be prepared in the form of an aqueous solution or a solution using another solvent, and may be prepared in the form of further addition of nitric acid, hydrochloric acid, or sulfuric acid for support activation.

According to the sequential impregnation method, the first metal is first supported on the carrier, and after the support is completed, the second metal is supported again.

Specifically, prepare water or other solvent as a medium for the supporting reaction, add an appropriate amount of nitric acid, hydrochloric acid, or sulfuric acid thereto, add the precursor of the first metal, stir, and remove the solvent. . Afterwards, optionally, it may further undergo a firing process at a temperature of about 500 to about 700°C.

Separately, after preparing a solution in which the precursor of the second metal is dissolved in water or other solvent to which an appropriate amount of nitric acid, hydrochloric acid, or sulfuric acid is added, a carrier carrying the first metal is added thereto, and then stirred. , by removing the solvent, a supported catalyst on which both the first and second metals are supported can be obtained, and optionally, a further calcination process may be performed at a temperature of about 500 to about 700° C.

When following the sequential impregnation method, there is an advantage of being able to effectively control the ratio of the first and second metals on the surface of the supported catalyst according to the loading order.

In the case of other sol-gel methods or co-precipitation methods, the process can be carried out without much difference from methods generally used in the technical field to which the present invention pertains, and the present invention is not necessarily limited thereto.

Meanwhile, the present invention provides a method for producing an alkene having 2 to 6 carbon atoms, comprising the step of carrying out a dehydrogenation reaction of an alkane having 2 to 6 carbon atoms in the presence of any of the catalysts described above. We would like to provide

As described above, the dehydrogenation reaction of an alkane can be briefly expressed as the following reaction mechanism and can proceed in two steps.

First, in the first step, each hydrogen bonded to an alkane having 2 to 6 carbon atoms is aligned in the catalytically active metal, and in any one hydrogen, the bond between carbon and hydrogen is broken, and the hydrogen It may be adsorbed on catalytically active metals and alkenyl radicals may be formed.

In the second step, the bond between carbon and hydrogen is broken in the other hydrogen bonded to the adjacent carbon, and the hydrogen is adsorbed to the catalytically active metal, forming a double bond between carbon and carbon.

Then, the hydrogen adsorbed on the catalytically active metal is released, and the catalyst can be regenerated.

At this time, the alkane having 2 to 6 carbon atoms is propane, butane, pentane, and hexane. At least one selected from the group consisting of hexane; The alkene having 2 to 6 carbon atoms may be one or more selected from the group consisting of propene, butane, pentene, and hexane, and more preferably, the alkene An alkane having 2 to 6 carbon atoms may be propane, and an alkene having 2 to 6 carbon atoms may be propene.

The alkane may be in a straight-chain or branched-chain form, and the alkene may also be in a straight-chain or branched-chain form depending on the structure of the alkane, which is a reactant. In this case, the edge portion or the middle of the straight-chain or branched chain. Among the parts, the double bond may be formed at any position where a double bond can be formed.

In addition, the dehydrogenation reaction of the alkane may proceed at two or more positions in the alkane molecule when the number of carbon atoms of the reactant is 4 or more, and in this case, the product may be produced in the form of a diene.

Specifically, if the reactant is butane, 1,3-butadiene may be formed as the product, and if the reactant is pentane, 1,3-pentadiene or 1,4-pentadiene may be formed as the product. When the reactant is hexane, the product is 1,3-hexadiene, 1,4-hexadiene, 1,5-hexadiene, 2,4-hexadiene, or 1,3,5-hexadiene. This may be formed.

When such a diene-type compound is formed, the dehydrogenation reaction of the alkane may proceed simultaneously at two or more positions in the alkane molecule, and the alkene is first formed through a first reaction, and then sequentially at other sites of the molecule. A second or third dehydrogenation reaction may proceed.

However, in terms of the reaction activity and selectivity of the catalytically active metal, it is most preferable that the reactant is propene, and accordingly, it is most preferable that the product is propene.

And, specifically, the method for producing an alkene having 2 to 6 carbon atoms includes activating the catalyst using an active gas; and contacting the activated catalyst with an alkane having 2 to 6 carbon atoms.

At this time, the active gas may be a reducing gas such as carbon monoxide, hydrogen, ethylene, ethane, or methane, and an inert gas such as nitrogen may be used as the carrier gas. This active gas can activate the catalyst by reacting with oxygen on the surface of the highly reactive catalyst.

This pretreatment may be carried out at a temperature of about 300 to about 600 °C.

Then, a dehydrogenation reaction can be carried out by contacting the activated catalyst with an alkane having 2 to 6 carbon atoms.

The dehydrogenation reaction may be carried out by supplying the alkane reactant in gaseous form to the inside of the reactor containing the catalyst under temperature conditions of about 300 to about 800 ° C., more preferably about 500 to about 700 ° C. there is. If the temperature is too low, the activity of the reaction may decrease, and if the temperature is too high, the decomposition reaction of the alkane used as a reactant may proceed.

And, when supplying, the alkane, which is a reactant, can be injected using an inert gas such as nitrogen as a carrier gas, and the injection amount can be adjusted by a mass flow rate controller or the like. The injection amount of the reactant (WHSV, weight hourly space velocity) may be about 1 to about 10/H, or about 3 to about 7/H, but the present invention is not necessarily limited thereto, and this depends on the specific composition of the catalyst used. However, it can be adjusted differently depending on the amount used or the reaction temperature.

The catalyst for the dehydrogenation reaction of alkanes according to one aspect of the present invention has high activity for the dehydrogenation reaction of alkanes, can maintain high activity for a long time, and shows high selectivity for specific alkenes.

Therefore, when producing an alkene using the catalyst according to one aspect of the present invention, a higher yield can be achieved compared to the existing method.

Figures 1 and 2 are XRD graphs of the carriers prepared in Examples 1 and 2 of the present application, respectively.

Hereinafter, the operation and effects of the invention will be described in more detail through specific examples of the invention. However, these examples are merely presented as examples of the invention, and the scope of the invention is not determined by them.

<Example>

Preparation of supported catalyst

Preparation of supported catalyst: Example 1 (Sn-Pt/Al ₂ O ₃ -One)

The Sn-Pt/Al ₂ O ₃ catalyst was manufactured by sequentially supporting the first and second metals.

Tin chloride dihydrate (junsei, 98%) was used as a precursor for tin (Sn), the second metal, and chloroplatinic acid hexahydrate (Sigma-aldrich, ≥37.50% Pt basis) was used as a precursor for platinum (Pt), the first metal. ) was used.

As a carrier, Al ₂ O ₃ (KHO-12 from Sumitomo) was used by heat treatment at about 700°C for about 10 hours.

Figure 1 is an XRD graph of the carrier prepared above.

Referring to Figure 1, it can be clearly seen that the carrier used in Example 1 was converted to the kappa phase.

Data related to the physical properties of the kappa phase alumina carrier are as follows.

BET surface area: 99.38 m ² /g; Average pore diameter: 14.8 nm; Pore volume: 0.3681 cm ³ /g; Total Acidity (NH ₃ -TPD): 0.54619 mmol/g

As a supporting solvent, an acidic aqueous solution with a pH of about 1.5 containing a small amount of HCl and HNO ₃ added to distilled water was used.

Based on 10 g of carrier, the catalyst was prepared so that the Sn supported amount was 1.0 wt% and the Pt supported amount was 0.5 wt%.

The amount of Pt precursor calculated by backward calculation based on the supported amount was added to the acid aqueous solution and completely dissolved, and then the heat-treated Al ₂ O ₃ was added.

Afterwards, after stirring at room temperature for about 1.5 hours using a rotary evaporator, the solvent was removed under reduced pressure conditions of about 80°C.

This was transferred to an oven, dried at about 105°C for about 15 hours, and then calcined at a temperature of about 600°C in an air atmosphere for about 3 hours to prepare a Pt/Al ₂ O ₃ catalyst.

After completely dissolving the amount of Sn precursor calculated by backward calculation based on the supported amount in the acid aqueous solution, the previously prepared Pt/Al ₂ O ₃ was added.

Afterwards, after stirring at room temperature for about 1.5 hours using a rotary evaporator, the solvent was removed under reduced pressure conditions of about 80°C.

This was transferred to an oven, dried at about 105°C for about 15 hours, and then calcined at a temperature of about 600°C in an air atmosphere for about 3 hours to prepare a Pt-Sn/Al ₂ O ₃ catalyst.

Preparation of supported catalyst: Example 2 (Sn-Pt/Al ₂ O ₃ -2)

The procedure was the same as Example 1, except that Al ₂ O ₃ (HD-13, Sumitomo) was used as a carrier and heat-treated at 700° C. for 10 hours.

Figure 2 is an XRD graph of the carrier prepared above.

Referring to Figure 2, it can be clearly seen that the carrier used in Example 1 was converted to the kappa phase.

Data related to the physical properties of the kappa phase alumina carrier are as follows.

BET surface area: 98.3 m ² /g; Average pore diameter: 15.2 nm; Pore volume: 0.3738 cm ³ /g; Total Acidity (NH ₃ -TPD): 0.44043 mmol/g

Preparation of supported catalyst: Comparative Example 1 (Sn-Pt/theta-Al ₂ O ₃ )

The same procedure as Example 1 was carried out, except that Al ₂ O ₃ (Sasol 1.6/130) was heat-treated at about 700° C. for about 10 hours as a carrier, and theta phase alumina was used.

Dehydrogenation reaction of propane progresses

Using the catalyst prepared in the above Examples and Comparative Examples, the dehydrogenation reaction of propane was carried out by the following method.

First, 0.03 g of quartz wool and 0.2 g of the supported catalyst were charged into a quartz reactor with an inner diameter of 0.8 cm and a length of 40 cm.

While raising the temperature of the reactor to about 10℃/min, a mixed gas of hydrogen (4ml/min) and nitrogen (46ml/min) was injected into the reactor for about 60 minutes, and then, nitrogen (44ml/min) was added for about 20 minutes. The liver was purged.

Afterwards, at 600°C and normal pressure, a mixed gas of propane (8 ml/min) and nitrogen (52 ml/min) was injected into the reactor at a WHSV of about 4.6/H, and the dehydrogenation reaction of propane was performed.

The reaction proceeded for about 60 minutes, and the product was analyzed at 5 minutes and about 60 minutes after the start of the reaction to confirm the decrease in catalyst activity as the reaction progressed.

After the reaction, the product was analyzed through gas chromatography (HP 6890N) equipped with a flame ionization detector (FID) and a thermal conductivity detector (TCD).

Through FID, products such as methane, ethane, ethene, and propene were analyzed, and through TCD, products such as hydrogen, methane, carbon monoxide, and carbon dioxide were analyzed, and through this, the conversion rate of propane to propene and propene were analyzed. Selectivity and yield of propene were calculated.

The analysis results are summarized in the table below.

carrier phase 5 minutes 60 minutes propane
conversion rate
(wt%) propene
selectivity
(wt%) transference number
(wt%) propane
conversion rate
(wt%) propene
selectivity
(wt%) transference number
(wt%) Example 1 Kappa 54.9 88.8 48.7 47.9 96.8 46.4 Example 2 Kappa 50.1 93.4 46.7 44.8 97.2 43.6 Comparative Example 1 Theta - - 47.7 - - 40.4

Referring to Table 1, the supported catalyst according to an example of the present invention has high activity for the dehydrogenation reaction of propane and high selectivity for propene, and the high activity and selectivity are as compared to the comparative example. You can see that it is maintained well.

Claims (12)

Comprising a carrier and a catalytically active metal supported on the carrier;
The catalytically active metal is selected from the group consisting of i) platinum (Pt) as a first metal, and ii) tin (Sn), zinc (Zn), cerium (Ce), iridium (Ir), and gallium (Ga). Contains at least one second metal;
The carrier includes alumina on kappa;
A supported catalyst for the dehydrogenation reaction of an alkane having 2 to 6 carbon atoms.
According to paragraph 1,
A supported catalyst for the dehydrogenation reaction of an alkane having 2 to 6 carbon atoms, comprising 10 to 500 parts by weight of the second metal based on 100 parts by weight of the first metal.
According to paragraph 1,
A supported catalyst for the dehydrogenation reaction of an alkane having 2 to 6 carbon atoms, comprising 0.01 to 10 parts by weight of the second metal based on 100 parts by weight of the carrier.
According to paragraph 1,
A supported catalyst for the dehydrogenation reaction of an alkane having 2 to 6 carbon atoms, comprising 0.01 to 10 parts by weight of the first metal based on 100 parts by weight of the carrier.
According to paragraph 1,
The catalytically active metal is a supported catalyst for the dehydrogenation reaction of an alkane having 2 to 6 carbon atoms, further comprising a Group 1 metal.
According to clause 5,
The Group 1 metal is contained in an amount of 10 to 200 parts by weight based on 100 parts by weight of the first metal. A supported catalyst for the dehydrogenation reaction of an alkane having 2 to 6 carbon atoms.
According to paragraph 1,
The kappa-phase alumina is a supported catalyst for the dehydrogenation reaction of an alkane having 2 to 6 carbon atoms, and has a BET surface area of 50 to 200 m ² /g.
According to paragraph 1,
The kappa phase alumina has an average pore diameter of 5 to 20 nm and a total pore volume of 0.2 to 0.7 cm ³ /g. A supported catalyst for the dehydrogenation reaction of an alkane having 2 to 6 carbon atoms.
According to paragraph 1,
The kappa-phase alumina is a supported catalyst for the dehydrogenation reaction of an alkane having 2 to 6 carbon atoms, and the amount of surface functional groups is 0.5 to 0.8 mmol/g.
A method for producing an alkene having 2 to 6 carbon atoms, comprising carrying out a dehydrogenation reaction of an alkane having 2 to 6 carbon atoms in the presence of the catalyst according to claim 1.
According to clause 10,
The alkane having 2 to 6 carbon atoms is at least one selected from the group consisting of propane, butane, pentane, and hexane;
The alkene having 2 to 6 carbon atoms is at least one alkene (alkene having 2 to 6 carbon atoms) selected from the group consisting of propene, butane, pentene, and hexene. Alkene) manufacturing method.
According to clause 10,
activating the catalyst using an activating gas; and
A method for producing an alkene having 2 to 6 carbon atoms, comprising contacting an activated catalyst with an alkane having 2 to 6 carbon atoms.