KR102496524B1 - Dissimilar metal supported catalyst for preparation of aromatic compounds by dehydroaromatization of methane and Method for preparing aromatic compounds using the same - Google Patents

Abstract

The present invention relates to a heterometal-supported catalyst for preparing an aromatic compound by dehydroaromatization of methane and a method for preparing an aromatic compound using the same.
The heterometal-supported catalyst according to the present invention is dehydrogenated by additionally introducing precious metals such as gold (Au), silver (Ag), platinum (Pt) and rhodium (Rh) into the catalyst in which iron (Fe) is supported on a zeolite support. By accelerating the formation of iron carbide (Fe ₃ C), which is an active species in the reaction and dehydroaromatization reaction, the production yield of aromatic compounds can be greatly improved.

Description

Dissimilar metal supported catalyst for preparation of aromatic compounds by dehydroaromatization of methane and Method for preparing aromatic compounds using the same}

The present invention relates to a heterometal-supported catalyst for preparing an aromatic compound by dehydroaromatization of methane and a method for preparing an aromatic compound using the same.

Aromatic compounds represented by benzene, toluene, and xylene are industrially very important compounds and are used as intermediate products of chemical products, solvents, and raw materials for polymers. In 2012, about 40 million tons of benzene and 14 million tons of toluene were produced, and demand for these products is expected to increase by 35% to 40% according to the global GDP growth rate.

Aromatic compounds having such high added value are currently mostly produced by a catalytic reforming process of naphtha, which relies on crude oil. However, this crude oil-dependent production process has limitations in that it can be significantly affected by rapid fluctuations in oil prices and limited reserves of crude oil. Therefore, there is a need for a new raw material-based aromatic compound production technology that is out of this crude oil-dependent production method.

On the other hand, recent developments in shale gas mining technologies such as horizontal drilling and hydraulic fracturing have lowered the unit cost of shale gas mining, causing significant changes in the global energy market. Natural gas, including shale gas, is composed of about 85% methane, 10% ethane, and light hydrocarbons such as propane. Considering the enormous reserves of natural gas, including shale gas, it would be industrially very important to synthesize high value-added compounds from them. Research on technologies for synthesizing high value-added compounds is being intensively studied.

Among them, a method for synthesizing an aromatic compound using the dehydroaromatization reaction of methane has been studied a lot due to the economic advantage of lower unit cost of the raw material itself compared to the existing crude oil-based aromatic compound synthesis method. Since the dehydroaromatization reaction of methane converts methane under non-oxidative conditions, high temperature reaction conditions of 700 ° C or more and an appropriate catalyst are required. The catalyst is a metal active site capable of activating methane as a reactant ), a bronsted acid site capable of causing oligomerization and aromatization of the active species of activated methane, and an appropriate size to selectively separate synthesized aromatic compounds (~ 0.5 nm) molecular sieve and other components are required. The dehydroaromatization reaction of methane is largely composed of activation of reactants through dehydrogenation of methane, oligomerization of activated components, and aromatization.

As a catalyst used for this reaction, a catalyst based on an HZSM-5 carrier supported with molybdenum (Mo) as an active metal has been widely used for the dehydroaromatization reaction of methane, but a satisfactory level of aromatic A limitation exists in that the yield of the compound cannot be shown.

The present invention has been made to solve the above-mentioned problems, in the present invention, gold (Au), silver (Ag), platinum (Pt), rhodium (Rh), etc. By additionally introducing a noble metal, the dehydrogenation reaction is promoted and the formation of iron carbide, which is an active species of the dehydroaromatization reaction, is promoted, thereby improving the yield of aromatic compounds. We want to provide a way.

The present invention, in order to solve the above problems,

zeolite support; A first metal that is supported on the zeolite carrier and is iron (Fe); And at least one second metal supported on the zeolite support and selected from the group consisting of gold (Au), silver (Ag), platinum (Pt) and rhodium (Rh); including, dehydroaromatization of methane It provides a heterogeneous metal-supported catalyst characterized in that it is used for the production of aromatic compounds by reaction.

According to the present invention, the first metal may be supported in an amount of 0.5 to 4 wt.% based on the total weight of the zeolite support.

According to the present invention, the second metal may be supported in an amount of 0.5 to 2 wt.% based on the total weight of the zeolite support.

According to the present invention, the iron (Fe) may be converted to iron carbide (Fe ₃ C) as the dehydroaromatization reaction of methane proceeds.

According to the present invention, the zeolite support may be selected from the group consisting of HZSM-5, ZSM-5, MCM-22, and MCM-41.

According to the present invention, the Si / Al ratio of the zeolite support may be 15 to 140.

In addition, the present invention to solve the above problems,

It provides a method for producing an aromatic compound including; performing a dehydroaromatization reaction using methane as a reactant under the supported heterogeneous metal catalyst.

According to the present invention, the reaction may be carried out in a gas phase reactor including a column packed with a heterometallic catalyst.

According to the present invention, argon gas may be further included as a reactant.

According to the present invention, the reaction may be carried out at 600 to 800 ℃.

According to the present invention, the aromatic compound may be at least one selected from the group consisting of benzene, toluene, xylene, naphthalene, and coke.

The heterometal-supported catalyst according to the present invention is dehydrogenated by additionally introducing precious metals such as gold (Au), silver (Ag), platinum (Pt) and rhodium (Rh) into the catalyst in which iron (Fe) is supported on a zeolite support. By accelerating the formation of iron carbide (Fe ₃ C), which is an active species in the reaction and dehydroaromatization reaction, the production yield of aromatic compounds can be greatly improved.

1 shows the result of calculating the formation rate of aromatic compounds through the dehydroaromatization reaction of methane according to the amount of supported iron.
Figure 2 is 2Fe / HZSM-5 (a), 2Fe-0.5Au / HZSM-5 (b), 2Fe-0.5Ag / HZSM-5 (c), 2Fe-0.5Pt / HZSM-5 (d) and 2Fe- It is a graph showing the XRD pattern of the 0.5Rh/HZSM-5(e) catalyst.
3 shows the concentration of methane using 2Fe/HZSM-5, 2Fe-0.5Au/HZSM-5, 2Fe-0.5Ag/HZSM-5, 2Fe-0.5Pt/HZSM-5 and 2Fe-0.5Rh/HZSM-5 catalysts. It shows the result of the formation rate of the initial aromatic compound when performing the dehydroaromatization reaction.
Figure 4 shows the concentration of methane using 2Fe/HZSM-5, 2Fe-0.5Au/HZSM-5, 2Fe-0.5Ag/HZSM-5, 2Fe-0.5Pt/HZSM-5 and 2Fe-0.5Rh/HZSM-5 catalysts. It shows the results of the formation rate of aromatic compounds over time when the dehydroaromatization reaction is performed.
Figure 5 shows the concentration of methane using 2Fe/HZSM-5, 2Fe-0.5Au/HZSM-5, 2Fe-0.5Ag/HZSM-5, 2Fe-0.5Pt/HZSM-5 and 2Fe-0.5Rh/HZSM-5 catalysts. It shows the accumulation result of the formation rate of aromatic compounds over time when the dehydroaromatization reaction is performed.
6 shows the results of measuring selectivity to aromatic compounds and selectivity to coke when methane is dehydroaromatized using 2Fe/HZSM-5 and 2Fe-0.5Au/HZSM-5 catalysts.
7 is a graph showing the profile of CH ₄ -TPSR for measuring the activation temperature of methane of 2Fe/HZSM-5 and 2Fe-0.5Au/HZSM-5 catalysts.
8 shows C 1s (FIG. 8a) and Fe 2p (FIG. 8b) for 2Fe/HZSM-5 and 2Fe-0.5Au/HZSM-5 catalysts and catalysts after dehydroaromatization of methane using the catalysts. And it shows the XPS analysis graph for the Au 4f (FIG. 8c) orbital.
9 shows the result of calculating the formation rate of aromatic compounds through the dehydroaromatization reaction of methane according to the supported gold content.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In general, the nomenclature used herein is one well known and commonly used in the art.

Hereinafter, the present invention will be described in more detail.

The present invention relates to a heterogeneous metal-supported catalyst for producing aromatic compounds by dehydroaromatization of methane. In the present invention, gold (Au) and silver (Ag) In order to provide a heterogeneous metal-supported catalyst capable of promoting the formation of iron carbide through the dehydrogenation reaction promotion by additionally introducing metals such as platinum (Pt) and rhodium (Rh), thereby improving the production yield of aromatic compounds do.

To this end, the present invention is a zeolite support; A first metal that is supported on the zeolite carrier and is iron (Fe); And at least one second metal supported on the zeolite support and selected from the group consisting of gold (Au), silver (Ag), platinum (Pt) and rhodium (Rh); including, dehydroaromatization of methane It provides a heterogeneous metal-supported catalyst characterized in that it is used for the production of aromatic compounds by reaction.

At this time, the first metal and the second metal may be supported by any conventional method known in the art, and may be more preferably supported by an initial wetting method.

In addition, as can be seen from the results of the following examples, iron, the first metal, is preferably supported in an amount of 0.5 to 4 wt.% based on the total weight of the zeolite support, and the content range of the first When a metal is supported, the rate of formation of an aromatic compound through the improvement of the dehydrogenation reaction may be remarkably increased.

In addition, as can be seen from the results of the following examples, the second metal is preferably supported in an amount of 0.5 to 2 wt.% based on the total weight of the zeolite carrier. If the content of the second metal is less than the lower limit or exceeds the upper limit, there is a problem in that the yield of the product (aromatic compound) is significantly lowered due to an insignificant effect of improving the dehydrogenation reaction during the dehydroaromatization of methane.

The zeolite used in the present invention is commonly used as a catalyst support, and may be selected from the group consisting of, for example, HZSM-5, ZSM-5, MCM-22, and MCM-41.

In addition, the Si / Al ratio of the zeolite support is preferably 15 to 140.

In addition, the present invention provides a method for preparing an aromatic compound comprising the step of carrying out a dehydroaromatization reaction using methane as a reactant in the presence of the above-mentioned heterogeneous metal-supported catalyst.

The dehydroaromatization reaction is preferably carried out in a gas phase reactor including a column packed with the heterometal supported catalyst, for example, a fixed bed gas phase reactor.

During the dehydroaromatization reaction, reactants may further include argon gas in addition to methane.

The dehydroaromatization reaction is preferably carried out at 600 to 800 °C.

The aromatic compound, which is a product of the dehydroaromatization reaction, may be at least one selected from the group consisting of benzene, toluene, xylene, naphthalene, and coke.

In addition, as in the following examples, the dehydroaromatization reaction performed using methane as a reactant under the heterogeneous metal-supported catalyst according to the present invention has a volume ratio of methane and argon of 2: 1, a GHSV of 4,500 ml / h g _cat , Most preferably, the reaction temperature is 750° C. and the reaction time is 1 hour.

Hereinafter, the present invention will be described in more detail through examples. These examples are only for illustrating the present invention, and it will be apparent to those skilled in the art that the scope of the present invention is not to be construed as being limited by these examples. Accordingly, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

manufacturing example 1. Various contents of iron supported Preparation of zeolite catalyst

First, NH ₄ -ZSM-5 (CBV 3024E, Zeolyst) with ammonium cations is heated at 5 ° C / min and calcined at 500 ° C for 5 hours HZSM-5 zeolite carrier with proton cations used as a catalyst carrier was manufactured.

Next, after dissolving 0.036, 0.072, 0.145, 0.29, 0.435, and 0.725 g of iron nitrate hydrate (Fe(NO ₃ ) 9H ₂ O , Sigma-Aldrich) in distilled water, 1.0 g of HZSM-5 carrier was supported by the initial wetting method and dried at 110° C. for 12 hours. After drying, the temperature was raised at 5 ° C / min under normal air conditions and calcined at 500 ° C for 5 hours to obtain 0.5, 1, 2, 4, 6, and 10 wt.% iron-supported zeolite catalysts (each 0.5 Fe/HZSM-5, 1Fe/HZSM-5, 2Fe/HZSM-5, 4Fe/HZSM-5, 6Fe/HZSM-5 and 10Fe/HZSM-5) were prepared.

manufacturing example 2. iron supported Gold, silver, platinum or rhodium in zeolite catalyst supported Preparation of Catalyst

manufacturing example 2-1. iron supported Silver, platinum or rhodium in zeolite catalyst supported Preparation of Catalyst

The zeolite catalyst supported with 2 wt.% iron, prepared according to Preparation Example 1, was dried at 110° C. for 12 hours. Next, 0.0079 g of silver nitrate (Ag(NO ₃ ), Sigma-Aldrich), 0.0086 g of platinum chloride (PtCl ₄ , Sigma-Aldrich) and 0.0080 g of rhodium nitrate Rh(NO ₃ ) ₃ xH After dissolving ₂ O (Sigma-Aldrich, ~36%) in distilled water, it was supported on 1.0 g of the iron-loaded HZSM-5 carrier using the initial wetting method. Then, after drying at 110 ° C for 12 hours, the temperature was raised at 5 ° C / min under general air conditions and fired at 500 ° C for 5 hours to obtain 2 wt.% of iron and 0.5 wt.% of silver and platinum based on the weight of the support. , or rhodium-supported zeolite catalysts (represented as 2Fe-0.5Ag/HZSM-5, 2Fe-0.5Pt/HZSM-5, and 2Fe-0.5Rh/HZSM-5, respectively) were prepared.

manufacturing example 2-2. iron supported The zeolite catalyst contains various amounts of gold. supported Preparation of Catalyst

The zeolite catalyst prepared according to Preparation Example 1 and loaded with 2 wt.% iron was dried at 110° C. for 12 hours. Next, after dissolving 0.002 g, 0.001 g, 0.02 g, 0.03 g, 0.04 g, and 0.06 g of gold chloride trihydrate (Au(III)Cl trihydrate, Sigma-Aldrich) in distilled water, the above 1.0 g of iron-loaded HZSM-5 carrier was loaded using the initial wetting method. Then, after drying at 110 ° C for 12 hours, the temperature was raised at 5 ° C / min under general air conditions and calcined at 500 ° C for 5 hours to obtain 2 wt.% of iron and, respectively, 0.1, 0.5, 1, 1.5 , 2 and 3 wt.% gold supported zeolite catalysts (2Fe-0.1Au / HZSM-5, 2Fe-0.5Au / HZSM-5, 2Fe-1Au / HZSM-5, 2Fe-1.5Au / HZSM-5, 2Fe-2Au/HZSM-5, 2Fe-3Au/HZSM-5) were prepared.

Experimental example One. supported Production of aromatic compounds through dehydroaromatization of methane according to iron content

An aromatic compound was produced by carrying out a dehydroaromatization reaction of methane using the catalysts according to Preparation Example 1, respectively. Specifically, 0.2 g of the catalyst prepared according to Preparation Example 1 was filled in a fixed-bed gas phase reactor having an outer diameter of 6.35 mm, and then heated to a reaction temperature of 750 ° C. in an atmosphere of ultra-high purity argon gas (99.999%). When the reaction temperature was reached, the argon gas was changed to a reaction gas having a methane:argon volume ratio of 2:1, and then the reaction gas was flowed at 15 ml/min to proceed for 1 hour. The reactants and products that passed through the catalyst layer of the fixed bed reactor were injected while being maintained at 230° C. by being directly connected to the gas chromatography. The formation rate of aromatics, which is a product, was calculated using the composition of the gas analyzed through gas chromatography, and the results are shown in FIG. 1 below.

As a result of the measurement, when the supported iron content was 0.5 to 4 wt.%, the formation rate of aromatic compounds through the dehydroaromatization reaction was significantly higher than when the supported iron content was 6 or 10 wt.%. In particular, it was confirmed that the formation rate of the aromatic compound was the best when the supported iron content was 2 wt.%.

Experimental example 2. XRD pattern analysis

2 shows XRD patterns of 2Fe/HZSM-5, 2Fe-0.5Au/HZSM-5, 2Fe-0.5Ag/HZSM-5, 2Fe-0.5Pt/HZSM-5, and 2Fe-0.5Rh/HZSM-5 catalysts. it's a graph

Through this, it was confirmed that the pattern of ZSM-5 having crystallinity appeared prominently in all of the catalysts, and in the case of iron supported as an active metal, since it was well and evenly dispersed on the support, no distinct peak was observed. In the case of catalysts containing gold, silver, platinum, and rhodium, it was confirmed that no clear peak was observed due to a small amount of loading.

Experimental example 3. iron supported Gold (Au) and silver ( Ag ), platinum (Pt) or rhodium (Rh) supported Production of aromatic compounds through dehydroaromatization of methane using a catalyst

A zeolite catalyst supported with 2 wt.% of iron is not loaded with noble metal, or a catalyst supported with 0.5 wt.% of gold, silver, platinum or rhodium (2Fe-/HZSM-5, 2Fe-0.5Au/HZSM-5, 2Fe-0.5Ag/HZSM-5, 2Fe-0.5Pt/HZSM-5, 2Fe-0.5Rh/HZSM-5) were subjected to dehydroaromatization of methane, respectively, to produce aromatic compounds. Specifically, 0.2 g of each of the above catalysts was filled in a fixed-bed gas phase reactor having an outer diameter of 6.35 mm, and then heated to a reaction temperature of 750° C. under an atmosphere of ultra-pure argon gas (99.999%). When the reaction temperature was reached, the argon gas was changed to a reaction gas having a methane:argon volume ratio of 2:1, and then the reaction gas was flowed at 15 ml/min to proceed for 1 hour. The reactants and products that passed through the catalyst layer of the fixed bed reactor were injected while being maintained at 230° C. by being directly connected to the gas chromatography. The formation rate of aromatics and selectivity of aromatic compounds were calculated using the composition of the gas analyzed through gas chromatography, and the results are shown in FIGS. 3 to 6 below.

As a result of the measurement, in the case of the catalyst (2Fe-/HZSM-5) without noble metal, no aromatic compound was formed due to the initial carbonization process, whereas the catalyst supported with 0.5 wt.% of gold, silver, platinum or rhodium ( 2Fe-0.5Au/HZSM-5, 2Fe-0.5Ag/HZSM-5, 2Fe-0.5Pt/HZSM-5, 2Fe-0.5Rh/HZSM-5), respectively about 1080.3 nmol _/ g _cat s, about 875.3 Aromatic compound formation rates of nmol/g _cat s _, about 802.8 nmol _/ g _cat s, and about 825.6 nmol/g _cat s were shown. When gold, silver, platinum or rhodium is additionally supported, aromatic compounds are formed It was confirmed that the rate was significantly improved, and in particular, when gold was additionally supported, it was confirmed that the formation rate of the aromatic compound was the best. In addition, as a result of comparing the selectivity for aromatic compounds of the catalyst (2Fe-/HZSM-5) without noble metal and the catalyst (2Fe-0.5Au/HZSM-5) additionally supported with gold, It was confirmed that the selectivity for aromatic compounds increased from 6.65% to 23.5%, and the selectivity for coke also decreased from 89.47% to 67.56%. In conclusion, when gold, silver, platinum or rhodium is additionally supported on the iron-supported zeolite catalyst according to the present invention, the formation rate and selectivity of aromatic compounds are significantly increased, and the selectivity to coke is reduced. did

Experimental example 4.CH ₄ - TPSR (Temperature-Programmed Surface Reaction)

7 is a graph showing the profile of CH ₄ -TPSR for measuring the activation temperature of methane of 2Fe/HZSM-5 and 2Fe-0.5Au/HZSM-5 catalysts.

Through this, the 2Fe/HZSM-5 catalyst supported only with iron starts to activate methane at around 752°C, whereas the 2Fe-0.5Au/HZSM-5 catalyst supported with iron and gold has a methane activation temperature of about 752 °C. It was confirmed that the activation temperature of methane decreased around 742 ° C., and through this, it was confirmed that the dehydrogenation reaction of methane was promoted due to the addition of gold.

Experimental example 5. XPS (X-ray Photoelectron Spectroscopy)

8 shows C 1s (FIG. 8a) and Fe 2p (FIG. 8b) for 2Fe/HZSM-5 and 2Fe-0.5Au/HZSM-5 catalysts and catalysts after dehydroaromatization of methane using the catalysts. And it shows the XPS analysis graph for the Au 4f (FIG. 8c) orbital.

Through this, it was confirmed that the 2Fe-0.5Au/HZSM-5 catalyst had a higher degree of reduction to iron carbide (Fe ₃ C) after the reaction compared to the conventional 2Fe/HZSM-5 catalyst, and the 2Fe/HZSM-5 catalyst When gold (Au) is additionally supported on , the interaction between Fe and Au results in a lack of Fe electrons, and Fe in this state promotes the reduction to iron carbide (Fe ₃ C) in the reaction, thereby increasing the catalyst It was confirmed that the dehydrogenation ability was improved.

That is, by introducing gold (Au) into the 2Fe/HZSM-5 catalyst according to the present invention, during the dehydroaromatization reaction of methane, the interaction between iron (Fe) and gold (Au) results in an electron-deficient Fe state, and this state It was confirmed that Fe can greatly improve the production yield of aromatic compounds by promoting reduction to iron carbide (Fe ₃ C).

Experimental example 6. supported Production of aromatic compounds through dehydroaromatization of methane, depending on the gold content

An aromatic compound was produced by carrying out a dehydroaromatization reaction of methane using the catalysts according to Preparation Example 2-2, respectively. Specifically, 0.2 g of each of the above catalysts was filled in a fixed-bed gas phase reactor having an outer diameter of 6.35 mm, and then heated to a reaction temperature of 750° C. under an atmosphere of ultra-pure argon gas (99.999%). When the reaction temperature was reached, the argon gas was changed to a reaction gas having a methane:argon volume ratio of 2:1, and then the reaction gas was flowed at 15 ml/min to proceed for 1 hour. The reactants and products that passed through the catalyst layer of the fixed bed reactor were injected while being maintained at 230° C. by being directly connected to the gas chromatography. The formation rate of aromatics, which is a product, was calculated using the composition of the gas analyzed through gas chromatography, and the results are shown in FIG. 9 below.

As a result of the measurement, when the supported gold content was 0.5 to 2 wt.%, the formation rate of aromatic compounds through the dehydroaromatization reaction was significantly higher than when the supported gold content was 0.1 or 3 wt.%. In particular, when the supported gold content was 1.5 wt.%, it was confirmed that the formation rate of the aromatic compound was the best.

Having described specific parts of the present invention in detail above, it is clear that these specific descriptions are only preferred embodiments for those skilled in the art, and the scope of the present invention is not limited thereby. something to do. Accordingly, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Claims (11)

zeolite support;
A first metal that is supported on the zeolite carrier and is iron (Fe); and
It is supported on the zeolite carrier and includes a second metal that is gold (Au),
The zeolite support is HZSM-5,
The first metal is supported in an amount of 1 to 2 wt.% based on the total weight of the zeolite support,
The second metal is supported in an amount of 0.5 to 2 wt.% based on the total weight of the zeolite support,
A heterometal-supported catalyst characterized in that it is used for the production of aromatic compounds by dehydroaromatization of methane. delete delete According to claim 1,
The iron (Fe) is a heterogeneous metal-supported catalyst, characterized in that converted to iron carbide (Fe ₃ C) as the dehydroaromatization reaction of methane proceeds. delete According to claim 1,
A heterometal supported catalyst, characterized in that the Si / Al ratio of the zeolite support is 15 to 140. A method for producing an aromatic compound comprising the step of carrying out a dehydroaromatization reaction using methane as a reactant under the heterogeneous metal-supported catalyst according to claim 1. According to claim 7,
The reaction is a method for producing an aromatic compound, characterized in that carried out in a gas phase reactor comprising a column packed with a heterogeneous metal catalyst. According to claim 7,
A method for producing an aromatic compound, further comprising argon gas as a reactant. According to claim 7,
The reaction is a method for producing an aromatic compound, characterized in that carried out at 600 to 800 ℃. According to claim 7,
The aromatic compound is a method for producing an aromatic compound, characterized in that at least one selected from the group consisting of benzene, toluene, xylene, naphthalene and coke.

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