WO2023106735A1 - Catalyst for preparation of aromatic compounds by dehydroaromatization, and method for preparing aromatic compounds using same - Google Patents

Abstract

The present invention relates to a catalyst for preparing aromatic compounds by a dehydroaromatization reaction and to a method for preparing aromatic compounds by using same. With respect to the catalyst for preparing aromatic compounds according to the present invention, a cobalt oxide is further incorporated in the catalyst in which a zinc oxide is supported on a zeolite support, so that deactivation of the catalyst can be suppressed, lifetime of the catalyst can be improved, and also the production yield of the aromatic compounds can be significantly improved.

Description

Catalyst for producing aromatic compounds by dehydroaromatization reaction and method for producing aromatic compounds using the same

The present invention relates to a catalyst for preparing an aromatic compound by dehydroaromatization reaction 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.

As such, aromatic compounds having high added value are currently mostly produced through a naphtha reforming reaction dependent on crude oil. However, since the naphtha reforming process is dependent on crude oil as a raw material, there are limitations in that it can be significantly affected by rapid oil price fluctuations 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, consists 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, the technology of producing aromatic compounds through dehydroaromatization using methane or ethane, which accounts for a large proportion among the components constituting natural gas, is attracting great attention, and the dehydroaromatization reaction of methane or ethane is largely Or, it is composed of activation of reactants through dehydrogenation of ethane, oligomerization of activated components, and aromatization.

As a catalyst used for this reaction, a catalyst based on HZSM-5 zeolite loaded with molybdenum (Mo), gallium (Ga), etc. has been widely used, but the catalyst is There are limitations in that it can undergo extreme deactivation, has a short lifetime of about 10-20 hours, and has a low yield of aromatic compounds.

The present invention has been made to solve the above problems, and in the present invention, by additionally introducing cobalt oxide into the catalyst supported on zinc oxide, the deactivation of the catalyst is suppressed, thereby stably maintaining the dehydroaromatization performance, and the lifespan And it is intended to provide a catalyst for preparing an aromatic compound capable of improving the cumulative yield of an aromatic compound and a method for preparing an aromatic compound using the same.

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

zeolite support; Zinc oxide supported on the zeolite support; and cobalt oxide mixed with the zinc oxide and supported on the zeolite carrier.

According to the present invention, the zinc oxide and the cobalt oxide may be supported in a weight ratio of 1:0.05 to 1:0.15.

According to the present invention, the zinc oxide may be supported in an amount of 8 to 12% by weight.

According to the present invention, the cobalt oxide may be supported in an amount of 0.5 to 1.5% by weight.

According to the present invention, the zeolite support may be selected from the group consisting of HZSM-5, ZSM-5, ZSM-11, MCM-22 and MCM-41.

According to the present invention, the Si / Al ratio of the zeolite support may be 11.5 to 140.

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

It provides a method for preparing an aromatic compound including; performing a dehydroaromatization reaction using methane, ethane or a mixture thereof as a reactant under the catalyst for preparing the aromatic compound.

According to the present invention, the dehydroaromatization reaction may be carried out in a gas phase reactor including a column filled with the catalyst for preparing the aromatic compound.

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

According to the present invention, the dehydroaromatization reaction may be carried out at 550 to 700 °C.

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.

Features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings.

Prior to this, the terms or words used in this specification and claims should not be interpreted in a conventional and dictionary sense, and the inventor may appropriately define the concept of the term in order to explain his or her invention in the best way. It should be interpreted as a meaning and concept consistent with the technical idea of the present invention based on the principle that there is.

The catalyst for preparing an aromatic compound according to the present invention can suppress deactivation of the catalyst and improve the lifespan of the catalyst by additionally introducing cobalt oxide into the catalyst in which zinc oxide is supported on the zeolite carrier, and can significantly increase the production yield of the aromatic compound. can be improved

1 shows the results of measuring the yield (BTX yield) of aromatic compounds according to the dehydroaromatization reaction of ethane of catalysts according to Examples and Comparative Examples of the present invention.

Figure 2 shows the results of measuring the cumulative aromatic compound production amount (Cumulative BTX formation) according to the dehydroaromatization reaction of ethane in the catalysts according to Examples and Comparative Examples of the present invention.

3 is a graph showing XRD patterns of catalysts according to Examples and Comparative Examples of the present invention (left drawing: 2θ = 4-54°, right drawing: 2θ = 30-40°

Figure 4 shows the results of TG (Thermogravimetric analysis) measurement after 40 hours of dehydroaromatization of ethane with catalysts according to Examples and Comparative Examples of the present invention.

5 shows the results of differential thermogravimetric analysis (DTG) after 40 hours of dehydroaromatization of ethane with catalysts according to Examples and Comparative Examples of the present invention.

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.

The present invention relates to a catalyst for producing an aromatic compound by a dehydroaromatization reaction. It is intended to provide a catalyst capable of improving the production yield of the compound.

To this end, the present invention is a zeolite support; Zinc oxide supported on the zeolite support; and cobalt oxide mixed with the zinc oxide and supported on the zeolite carrier.

In this case, the zinc oxide and the cobalt oxide may be supported by any conventional method known in the art, and it may be more preferable that the zinc oxide and the cobalt oxide are supported by an initial wetting method.

Also, the zinc oxide may be zinc oxide (ZnO).

In addition, the cobalt oxide may be CoO, Co ₃ O ₄ or a mixture thereof.

In addition, as can be seen from the results of the following examples, the zinc oxide and the cobalt oxide are preferably supported at a weight ratio of 1:0.05 to 1:0.15, and preferably at a weight ratio of 1:0.075 to 1:0.1. more preferable When zinc oxide and cobalt oxide are supported at the above weight ratio, deactivation of the catalyst is suppressed, the life of the catalyst is improved, and the production yield of aromatic compounds through the improvement of the dehydrogenation reaction can be remarkably increased.

In addition, as can be seen from the results of the following examples, the zinc oxide is preferably supported in an amount of 8 to 12% by weight based on the total weight of the zeolite carrier, and the content of 10% by weight is most preferred. desirable. When zinc oxide is supported in the above content range, the rate of formation of aromatic compounds through the improvement of dehydrogenation reaction may be remarkably increased.

In addition, as can be seen from the results of the following examples, the cobalt oxide is preferably supported in an amount of 0.5 to 1.5% by weight based on the total weight of the zeolite support, and supported in an amount of 0.75 to 1% by weight it is more preferable When the content of cobalt oxide is less than the lower limit, the effect of improving the lifespan and dehydrogenation reaction of the catalyst is insignificant, and when the content exceeds the upper limit, the deactivation of the catalyst is accelerated and the life of the catalyst is reduced, and as a result, the productivity of aromatic compounds is reduced. can

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, ZSM-11, MCM-22 and MCM-41.

In addition, the Si / Al ratio of the zeolite support is preferably 11.5 to 140.

In addition, the present invention provides a method for preparing an aromatic compound comprising the steps of performing a dehydroaromatization reaction using methane, ethane or a mixture thereof as a reactant under the above-mentioned catalyst for preparing an aromatic compound.

At this time, the dehydroaromatization reaction is preferably carried out in a gas phase reactor including a column filled with the catalyst for preparing the aromatic compound, for example, a fixed bed gas phase reactor.

During the dehydroaromatization reaction, reactants may further include argon gas in addition to methane, ethane or a mixture thereof.

The dehydroaromatization reaction is preferably carried out at 550 to 700 °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 carried out using ethane as a reactant under the catalyst for producing an aromatic compound according to the present invention is a reaction gas with a composition of 60 vol.% ethane / 40 vol.% argon, 6000 mL / h GHSV of g _cat , it is most preferably carried out under the reaction temperature conditions of 600 ℃.

[Example]

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.

Example 1. Zinc oxide and cobalt oxide supported Preparation of zeolite catalyst 0.5CoZn/HZSM-5

First, NH ₄ -ZSM-5 (CBV 3024E, Zeolyst) with ammonium cations is heated at 1 °C/min and calcined at 600 °C for 10 hours to support HZSM-5 zeolite with proton cations, which is used as a catalyst carrier. A delay was made.

Next, 0.9100 g of zinc nitrate hydrate (Zn(NO ₃ ) ₂ 6H ₂ O, Sigma-Aldrich) was dissolved in distilled water, and then supported on 2.0 g of HZSM-5 carrier by the initial wetting method and at 110 ° C. dried for a day. After drying, the temperature was raised at 1° C./min under atmospheric conditions and calcined at 500° C. for 4 hours to carry 10% by weight of zinc oxide (ZnO) based on the weight of the carrier.

Then, after dissolving 0.0494 g of cobalt nitrate hydrate (Co(NO ₃ ) ₂ 6H ₂ O, Sigma-Aldrich) in distilled water, 2.0 g of the zinc oxide-supported HZSM-5 carrier was pre-wetted. It was supported and dried at 110 ° C for one day. After drying, the temperature was raised at 1 ° C / min under atmospheric conditions and calcined at 500 ° C for 4 hours to obtain 0.5% by weight of cobalt oxide (CoO and Co ₃ O ₄ zeolite catalyst 0.5CoZn/HZSM-5 supported with 10% by weight of zinc oxide) was prepared.

Example 2. zinc oxide and cobalt oxide supported Preparation of zeolite catalyst 0.75CoZn/HZSM-5

_0.75 % by weight _of cobalt oxide ( _CoO and Co ₃ O ₄ zeolite catalyst 0.75CoZn/HZSM-5 supported with 10% by weight of zinc oxide) was prepared.

Example 3. zinc and cobalt supported zeolite catalyst 1CoZn / HZSM Manufacture of -5

_{1 %} by weight _of cobalt oxide (CoO and Co ₃ O ₄ zeolite catalyst 1CoZn/HZSM-5 supported with 10% by weight of zinc oxide) was prepared.

comparative example 1. Zinc Oxide supported Zeolite Catalyst Zn/ HZSM Manufacture of -5

First, NH ₄ -ZSM-5 (CBV 3024E, Zeolyst) with ammonium cations is heated at 1 °C/min and calcined at 600 °C for 10 hours to support HZSM-5 zeolite with proton cations, which is used as a catalyst carrier. A delay was made.

Next, 0.9100 g of zinc nitrate hydrate (Zn(NO ₃ ) ₂ 6H ₂ O, Sigma-Aldrich) was dissolved in distilled water, and then supported on 2.0 g of HZSM-5 carrier by the initial wetting method and at 110 ° C. dried for a day. After drying, the temperature was raised at 1 ° C / min under atmospheric conditions and calcined at 500 ° C for 4 hours to prepare a zeolite catalyst Zn / HZSM-5 supported with 10% by weight of zinc oxide based on the weight of the carrier.

comparative example 2. Zinc oxide and cobalt oxide supported Preparation of zeolite catalyst 2CoZn/HZSM-5

_{2 %} by weight _of cobalt oxide (CoO and Co ₃ O ₄ zeolite catalyst 2CoZn/HZSM-5 supported with 10% by weight of zinc oxide) was prepared.

Experimental example 1. Production of aromatic compounds through dehydroaromatization of ethane

An aromatic compound was produced by carrying out a dehydroaromatization reaction of ethane using the catalysts according to the above examples and comparative examples, respectively. The catalysts were used after separating only catalyst particles having a uniform size of 125-250 μm using a mesh sieve. Next, 0.05 g of the catalyst was filled in a fixed-bed quartz reactor having an outer diameter of 8 mm, and the temperature was raised to 600° C., the reaction temperature, under an argon atmosphere at a flow rate of 5 mL/min. When the reaction temperature is reached, the reaction gas is changed to a reaction gas having a composition of 60 vol.% ethane/40 vol.% argon, and then the reaction gas is flowed at 5 mL/min to react for 44 hours under the GHSV condition of 6000 mL/h g _cat . proceeded. Using the composition of the gas analyzed through gas chromatography, the yield (BTX yield) and cumulative aromatic compound production (Cumulative BTX formation) of the aromatic compound as a product were measured, and the results are shown in FIGS. 1 and 2, respectively.

As shown in FIG. 1, all catalysts showed the maximum BTX yield at 1 hour after reaction, and then the BTX yield decreased steadily. In the case of the zinc oxide single metal catalyst (Zn/HZSM-5) (Comparative Example 1) without cobalt support, the life of the catalyst was about 12 hours due to rapid deactivation. On the other hand, when cobalt oxide is additionally supported, the life of the catalyst tends to increase. Specifically, the lifespan of the catalyst 0.5CoZn / HZSM-5 according to Example 1 increased to about 18 hours, and the lifespan of the catalyst 0.75CoZn / HZSM-5 according to Example 2 significantly increased to about 33 hours, The lifespan of the catalyst 1CoZn/HZSM-5 according to Example 3 showed a BTX yield of 6.3% even after 40 hours, and the lifespan was remarkably increased to more than 40 hours. In particular, the BTX yield was 12.0% even after 20 hours. It was found to be very stable. On the other hand, in the case of the catalyst according to Comparative Example 2, that is, the catalyst 2CoZn/HZSM-5 in which an excessive amount of cobalt oxide was introduced, it was deactivated in 7 hours, showing a lower BTX yield than the conventional zinc oxide single metal catalyst. This is because ethylene as a reaction intermediate and BTX as a target product were not produced due to excessive dissociation of C-C and C-H bonds due to the introduction of an excessive amount of Co.

Next, as shown in FIG. 2, in the case of the zinc oxide single metal catalyst (Zn / HZSM-5) according to Comparative Example 1, the cumulative BTX production amount for 40 hours was 5.8 mmol / g _cat , and cobalt oxide was introduced in excess In the case of the catalyst 2CoZn / HZSM-5 according to Comparative Example 2, the cumulative BTX production amount for 40 hours was 2.6 mmol / g _cat , which was lower than that of Comparative Example 1, whereas the catalyst 0.5 CoZn / HZSM-5 according to Examples 1 to 3 of the present invention In the case of HZSM-5, 0.75CoZn/HZSM-5, and 1CoZn/HZSM-5, the cumulative BTX production for 40 hours was 7.7, 13.2, and 26.0 mmol/g _cat , indicating that BTX productivity was improved. It was confirmed that the catalysts according to Examples 2 to 3 had very good BTX productivity.

In conclusion, as the cobalt oxide is additionally supported, the yield of the aromatic compound and the production of the aromatic compound can be improved (Examples 1 to 3), especially when the content of the supported cobalt oxide is 0.75 to 1% by weight. (Examples 2 to 3) It was confirmed that the performance was very excellent.

Experimental example 2. XRD pattern analysis

XRD (X-ray powder diffraction) analysis was performed on the catalysts according to Examples and Comparative Examples, and the results are shown in FIG. 3 below.

As a result, it was confirmed that all of the catalysts showed a typical ZSM-5 zeolite pattern with peaks at 2 theta values of 7.9, 23.0, 23.1, and 23.9 °, and the synthesized catalysts all showed the structure of ZSM-5. confirmed that it has. In addition, ZnO shows peaks at 2 theta values of 31.8 and 36.2 °, and the peaks appear distinctly in the zinc oxide single metal catalyst, but the intensity of the peak significantly decreases after the introduction of cobalt oxide. This is because the dispersion of ZnO increased, and it was confirmed that the dispersion of ZnO increased due to the interaction between Co and Zn after the introduction of cobalt oxide.

Experimental example 3. TG analysis of the catalyst after the reaction

After carrying out the dehydroaromatization reaction of ethane using the catalysts according to the above Examples and Comparative Examples, after the reaction, the catalyst was analyzed by thermogravimetric analysis (TG) and differential thermogravimetric analysis (DTG), and the results are shown in FIGS. 4 and 4 below. shown in Figure 5.

As a result, the weight change of the catalyst, that is, the amount of coke deposited on the catalyst, was 9.1, 22.1, 47.6, and 68.6 for Zn/HZSM-5, 0.5CoZn/HZSM-5, 1CoZn/HZSM-5, and 2CoZn/HZSM-5, respectively. It was found to increase rapidly as the content of Co in % increased.

In the case of the DTG profile, it was deconvolved with a Gaussian peak. Amorphous carbon is the coke that burns at the lowest temperature, carbon nanotube (CNT) is the coke that burns at the medium temperature, and graphite is the coke that burns at the highest temperature. In the catalyst Zn/HZSM-5 according to Comparative Example 1, graphite was the dominant species, but the amount of graphite decreased and the amount of CNT increased as the Co content increased. From these results, when cobalt oxide is additionally introduced according to the present invention, the amount of coke-in graphite that deactivates the catalyst can be reduced by converting the coke precursor into CNTs to block the entrance of the micropores of ZSM-5, thereby reducing the amount of coke-in graphite. It was confirmed that the life of the catalyst can be extended.

Experimental example 4. Nitrogen in catalyst after reaction adsorption/desorption analyze

After the ethane dehydroaromatization reaction was performed using the catalysts according to the Examples and Comparative Examples, nitrogen adsorption and desorption analysis was performed on the catalyst after the reaction, and the results are shown in Table 1 below.

As shown in Table 1, in Zn/HZSM-5 and 0.5CoZn/HZSM-5, the total pore volume after reaction was 0.35 cm ³ /g to 0.18 cm 3 /g and 0.25 cm ^{3 /} g to 0.19 cm ³ respectively. /g. However, in 1CoZn/HZSM-5 and 2CoZn/HZSM-5, it increased from 0.24 cm ³ /g to 0.67 cm ³ /g and from 0.28 cm ³ /g to 0.91 cm ³ /g, respectively. This is because a large amount of CNTs grew during the reaction in the latter two catalysts, and the space inside the CNTs was measured as pores. After the reaction in all catalysts, the micropore volume decreased, which is usually due to the deposition of graphite at the pore inlets and clogging of the pores. The micropore volumes of Zn/HZSM-5, 0.5CoZn/HZSM-5, 1CoZn/HZSM-5, and 2CoZn/HZSM-5 were respectively 0.13, 0.10, 0.11, and 0.11 cm ³ /g after reaction, 0.01, and 2CoZn/HZSM-5, respectively. It decreased to 0.02, 0.05, and 0.06 cm ³ /g. The decrease in micropore volume was most severe in Zn/HZSM-5 and suppressed as the Co content increased. In particular, considering that the proportion of zeolite in the catalyst decreases as the amount of coke deposited increases as the Co content increases, it is determined that the clogging of micropores by coke is not significant as the Co content increases. This is because, as confirmed in Experimental Example 3, the graphite blocking the micropores of the catalyst was reduced as cobalt was additionally introduced, and through this result, when cobalt oxide is additionally introduced according to the present invention, the deactivation of the catalyst is delayed, resulting in ethane dehydrogenation of aromatics. It was confirmed that the catalyst activity stability can be increased in the reaction.

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.

In the catalyst of the present invention, the deactivation of the catalyst is suppressed, the life of the catalyst is improved, and the production yield of the aromatic compound is remarkably improved by additionally introducing cobalt oxide into the catalyst in which zinc oxide is supported on the zeolite support. It can be usefully used in the process of producing compounds and related fields.

Claims (11)

1. zeolite support;

   Zinc oxide supported on the zeolite support; and

   A catalyst for producing an aromatic compound by a dehydroaromatization reaction comprising: cobalt oxide mixed with and supported on the zeolite carrier.
2. According to claim 1,

   The catalyst for producing an aromatic compound, characterized in that the zinc oxide and the cobalt oxide are supported in a weight ratio of 1:0.05 to 1:0.15.
3. According to claim 1,

   The zinc oxide is a catalyst for producing an aromatic compound, characterized in that supported in an amount of 8 to 12% by weight.
4. According to claim 1,

   The cobalt oxide is a catalyst for producing an aromatic compound, characterized in that supported in an amount of 0.5 to 1.5% by weight.
5. According to claim 1,

   The catalyst for producing an aromatic compound, characterized in that the zeolite support is selected from the group consisting of HZSM-5, ZSM-5, ZSM-11, MCM-22 and MCM-41.
6. According to claim 1,

   A catalyst for producing an aromatic compound, characterized in that the Si / Al ratio of the zeolite support is 11.5 to 140.
7. A method for preparing an aromatic compound comprising: performing a dehydroaromatization reaction using methane, ethane or a mixture thereof as a reactant under the catalyst for preparing an aromatic compound according to claim 1.
8. According to claim 7,

   The method for producing an aromatic compound, characterized in that the dehydroaromatization reaction is carried out in a gas phase reactor comprising a column filled with the catalyst for preparing the aromatic compound.
9. According to claim 7,

   A method for producing an aromatic compound of an aromatic compound, further comprising argon gas as a reactant.
10. According to claim 7,

    The dehydroaromatization reaction is a method for producing an aromatic compound, characterized in that carried out at 550 to 700 ℃.
11. 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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