WO2021040314A1

WO2021040314A1 - Galloaluminosilicate catalyst, method of preparing same galloaluminosilicate catalyst, and method of preparing btx using same galloaluminosilicate catalyst

Info

Publication number: WO2021040314A1
Application number: PCT/KR2020/011072
Authority: WO
Inventors: 김도희; 김민영; 임용현; 이관영
Original assignee: 서울대학교산학협력단
Priority date: 2019-08-23
Filing date: 2020-08-20
Publication date: 2021-03-04
Also published as: KR102265476B1; KR20210023514A

Abstract

Provided are a galloaluminosilicate catalyst, a method of preparing the galloaluminosilicate catalyst, and a method of preparing BTX using the galloaluminosilicate catalyst. The method of preparing the galloaluminosilicate catalyst comprises: a step of forming a precursor solution comprising a silicone precursor, an aluminum precursor, a gallium precursor, and a carbon template material; and a step of crystallizing the precursor solution to form a galloaluminosilicate catalyst. The galloaluminosilicate catalyst is prepared by the method and has gallium atoms positioned within crystals of the galloaluminosilicate catalyst. The method of preparing BTX comprises: a step of filling a reactor with the galloaluminosilicate catalyst; a step of raising a temperature of the reactor to a reaction temperature; and a step of providing propane to the reactor to conduct a dehydroaromatization reaction.

Description

Gallo aluminosilicate catalyst, method for preparing the gallo aluminosilicate catalyst, and method for producing BTX using the gallo aluminosilicate catalyst

The present invention relates to a galloaluminosilicate catalyst, a method for preparing the galloaluminosilicate catalyst, and a method for preparing BTX using the galloaluminosilicate catalyst.

BTX, which refers to benzene, toluene, and xylene, is a high value-added compound used as a raw material for nylon, polystyrene, and the like, and their demand is increasing. Currently, most of BTX is produced by the naphtha reforming process. As crude oil prices increase and are unstable, research is being conducted to manufacture BTX from raw materials other than crude oil.

LPG gas production has more than doubled in the last 20 years and is expected to continue to increase in the future. Therefore, attempts to convert LPG gas to BTX have been made steadily, and studies are underway to make BTX using propane and butane, which are major components of LPG, as reactants. The BTX is formed by the dehydrogenation aromatication reaction of the propane, and conventionally proposed catalysts have low reaction activity and low yield or unstable problems.

In order to solve the above problems, the present invention provides a galoaluminosilicate catalyst having excellent performance.

The present invention provides a method for preparing the galloaluminosilicate catalyst.

The present invention provides a method for producing BTX using the gallo aluminosilicate catalyst.

Other objects of the present invention will become apparent from the following detailed description and accompanying drawings.

A method of manufacturing a galloaluminosilicate catalyst according to embodiments of the present invention includes forming a precursor solution including a silicon precursor, an aluminum precursor, a gallium precursor, and a carbon template material, and crystallizing the precursor solution to obtain galloalumino. Forming a silicate catalyst.

The galloaluminosilicate catalyst according to the embodiments of the present invention is a galloaluminosilicate catalyst prepared by the above method, and a gallium atom is located in the crystal of the galloaluminosilicate catalyst.

The BTX production method according to the embodiments of the present invention includes: filling the galloaluminosilicate catalyst into a reactor, raising the temperature of the reactor to a reaction temperature, and providing a front panel to the reactor to perform a dehydrogenation aromatication reaction. Including the step of performing.

The galloaluminosilicate catalyst according to the embodiments of the present invention may have excellent performance. For example, the galoaluminosilicate catalyst has excellent acid properties and structural properties and is effective in propane dehydrogenation aromatication. In addition, by optimizing the Al/Ga molar ratio of the galloaluminosilicate catalyst, the BTX yield of the propane dehydrogenation aromatication reaction can be further increased. A galloaluminosilicate catalyst having mesopores can be effectively prepared by using an inexpensive carbon template material.

1 shows the results of X-ray diffraction analysis of a meso-GAS x:y catalyst according to embodiments of the present invention, a micro-GAS x:y catalyst according to comparative examples, and a GaOy/meso-HZSM-5 catalyst.

2 to 5 show the results of nitrogen adsorption and desorption experiments of the meso-GAS x:y catalyst according to the embodiments of the present invention and the micro-GAS x:y catalyst according to the comparative examples and the GaOy/meso-HZSM-5 catalyst. Show.

^{6 and 7 are 71} Ga-NMR and ²⁷ of the meso-GAS x:y catalyst according to embodiments of the present invention and the micro-GAS x:y catalyst according to comparative examples and the GaOy/meso-HZSM-5 catalyst. The results of Al-NMR analysis are shown.

8 and 9 are results of an elevated temperature ammonia adsorption and desorption experiment of a meso-GAS x:y catalyst according to embodiments of the present invention and a micro-GAS x:y catalyst according to comparative examples and a GaOy/meso-HZSM-5 catalyst. Represents.

10 and 11 show the propane dehydrogenation aromatization conversion rate and BTX yield of the meso-GAS x:y catalyst according to examples of the present invention and the micro-GAS x:y catalyst according to comparative examples.

12 and 13 show the conversion rate of the propane dehydrogenation aromatication reaction and the BTX yield of the meso-GAS 6:1 catalyst and the GaO _{y /meso-HZSM-5 catalyst.}

Hereinafter, the present invention will be described in detail through examples. Objects, features, and advantages of the present invention will be easily understood through the following embodiments. The present invention is not limited to the embodiments described herein, and may be embodied in other forms. The embodiments introduced herein are provided so that the disclosed contents may be thorough and complete, and the spirit of the present invention may be sufficiently transmitted to those of ordinary skill in the art to which the present invention pertains. Therefore, the present invention should not be limited by the following examples.

In the present specification, terms such as first and second are used to describe various elements, but the elements should not be limited by these terms. These terms are only used to distinguish the elements from each other.

The method of manufacturing a galloaluminosilicate catalyst according to embodiments of the present invention includes forming a precursor solution including a silicon precursor, an aluminum precursor, a gallium precursor, and a carbon template material, and crystallizing the precursor solution to obtain galloalumino. Forming a silicate catalyst.

The forming of the galloaluminosilicate catalyst includes forming a first galloaluminosilicate by performing a crystallization process on the precursor solution, and performing a first sintering process on the first galloaluminosilicate to carbon Removing the template material, adding the first galloaluminosilicate to an ion exchange solution to perform ion exchange to form a second galloaluminosilicate, and a second firing process for the second galoaluminosilicate It may include the step of performing.

The silicon precursor may include tetraethyl orthosilicate, the aluminum precursor may include sodium aluminate, and the gallium precursor may include gallium nitrate.

The precursor solution may further include sodium hydroxide and terpopropylammonium bromide.

In the galloaluminosilicate catalyst, the molar ratio of aluminum:gallium may be 10:1 to 1:10. The galloaluminosilicate catalyst may have mesopores.

The step of raising the temperature of the reactor may be performed under a nitrogen atmosphere. The reaction temperature may be 500 ~ 600 ℃.

[Example 1: Preparation of a galloaluminosilicate catalyst having mesopores (medium pores)]

Sodium hydroxide 1.30 g, tetrapropylammonium bromide 1.36 g, tetraethyl orthosilicate 38.2 ml, and sodium aluminate and gallium nitrate (Si/(Al+Ga) were fixed at about 27, and Al:Ga A precursor solution was prepared by dissolving the molar ratio of 6:1, 4:3, and 1:6 in 108 ml of distilled water, and stirred at room temperature for 2 hours. A carbon template material (BP-2000, Cabot Corp.) was added to the precursor solution so as to be 1% by weight, followed by stirring for an additional 4 hours. The mixture was injected into a batch reactor and stirred at a temperature of 160° C. for 72 hours to perform a crystallization process. Through this hydrothermal synthesis process, Na ⁺ type galoaluminosilicate was prepared. A washing process using 1000 ml of distilled water and a drying process at 110° C. for 8 hours were performed, and the temperature was raised to 5° C. per minute in an air atmosphere, and a sintering process was performed at 550° C. for 10 hours to burn the carbon template material. Dissolve 8.01 g of ammonium nitrate in 100 ml of distilled water to make an ion exchange solution, and after ion exchange at a temperature of 130°C for 6 hours by injecting a calcined catalyst, a washing process using 1000 ml of distilled water and a drying process at 110°C for 8 hours Through the process, a galloaluminosilicate in the form of _{NH 4} ^{+ was prepared.} The ion exchange process was performed a total of two times. The galloaluminosilicate in the form of NH ₄ ⁺ was heated to 5° C. per minute, maintained at 550° C. for 5 hours, and then calcined to prepare a gallo aluminosilicate in the form of ^{H +.} The catalyst thus prepared is expressed in the present specification as meso-GAS x:y (GAS is an abbreviation for Galloaluminosilicate, and x:y is the molar ratio of Al:Ga). For example, when the molar ratio of Al:Ga is 6:1, the galloaluminosilicate catalyst is expressed as meso-GAS 6:1.

[Comparative Example 1: Preparation Example of Galoaluminosilicate Catalyst Having Micropores (Micropores)]

It was prepared in the same manner as in Example 1, but was injected into a batch reactor without adding a carbon template material to the precursor solution to perform a crystallization process to prepare microporous galoaluminosilicate. The catalyst thus prepared is expressed in the present specification as micro-GAS x:y (GAS is an abbreviation for Galloaluminosilicate, and x:y is the molar ratio of Al:Ga). For example, when the molar ratio of Al:Ga is 6:1, the galloaluminosilicate catalyst is expressed as micro-GAS 6:1.

_{[Comparative Example 2: Preparation Example of GaO y} /meso-HZSM-5 catalyst supporting gallium oxide and having mesopores]

1.30 g of sodium hydroxide, 1.36 g of tetrapropylammonium bromide, 38.2 ml of tetraethyl orthosilicate, and sodium aluminate (a content corresponding to a Si/Al ratio of 27) were dissolved in 108 ml of distilled water to make a precursor solution, and at room temperature Stir for 2 hours. A carbon template material (BP-2000, Cabot Corp.) was added to the precursor solution so as to be 1% by weight, followed by stirring for an additional 4 hours. After the procedure, the HZSM-5 catalyst having mesopores was prepared in the same manner as in Example 1. The catalyst thus prepared is referred to herein as meso-HZSM-5. Gallium was supported on meso-HZSM-5 using a wet impregnation method. A metal oxide precursor solution was prepared by adding 0.025 g of a gallium nitrate precursor (Ga content such as meso-GAS 6:1) to 10 ml of distilled water, and 1 g of meso-HZSM-5 was added to the precursor solution, and then 300 per minute at 85°C. The mixture was stirred until the moisture was completely evaporated at the rotational speed. After passing through the drying process at 100° C. for 8 hours, the temperature was raised to 550° C. at a rate of 5° C. per minute, and kept for 4 hours, followed by firing. The catalyst thus prepared _{is referred to herein as GaO y} /meso-HZSM-5.

[Analysis Example 1: Characterization and comparison of meso-GAS x:y catalyst, micro-GAS x:y catalyst, and GaO _y /meso-HZSM-5 catalyst]

Referring to FIG. 1, all catalysts show characteristic peaks of the ZSM-5 crystal phase, indicating that all catalysts form crystals having a ZSM-5 structure well. The meso-GAS x:y catalyst was found to have similar relative sensitivity compared to the micro-GAS x:y, so it does not appear to have a significant effect on the crystallinity even though the carbon template material acted as an impurity during the crystallization process. In addition, when comparing the GAS catalyst and the GaOy/meso-HZSM-5 catalyst, there was no significant difference in relative sensitivity. Although some of the aluminum in the MFI zeolite structure was replaced with gallium, it was judged that it did not significantly affect the crystallinity.

2 to 5, IV-type nitrogen adsorption and desorption isotherms are shown in all catalysts, showing the characteristics of typical mesoporous materials. When comparing Micro-GAS x:y and meso-GAS x:y, meso-GAS x:y shows a more pronounced hysteresis loop due to the influence of the carbon template material.

Table 1 shows the structural properties of the meso-GAS x:y catalyst, the micro-GAS x:y catalyst, and the GaOy/meso-HZSM-5 catalyst.

Referring to Table 1, according to the Al:Ga molar ratio, the micro-GAS catalyst has a specific surface area of 356 ~ 429m ² _/ g, a micropore (micropore) volume of 0.157 ~ 0.209cm ³ /g, and a medium pore (mesopores) volume. Is 0.065 ~ 0.165cm ³ /g. The meso-GAS catalyst has a specific surface area of 477 ~ 653m ² _/ g, a micropore volume of 0.221 ~ 0.287 cm ³ /g, and a mesopore volume of 0.111 ~ 0.0.278 cm ³ /g depending on the Al:Ga molar ratio. Comparing the micro-GAS catalyst and the meso-GAS catalyst of the same Al:Ga molar ratio, the meso-GAS catalyst has a large specific surface area and pore volume, indicating that a catalyst structure with improved porosity was formed by the carbon template material. When comparing the meso-GAS 6:1 catalyst with the same gallium content and the GaOy/meso-HZSM-5 catalyst, the surface area and pore volume of the meso-GAS 6:1 catalyst are larger.

[Table 1]

^{6 and 7 are 71} Ga-NMR and ²⁷ of the meso-GAS x:y catalyst according to embodiments of the present invention and the micro-GAS x:y catalyst according to comparative examples and the GaOy/meso-HZSM-5 catalyst. The results of Al-NMR analysis are shown. The metal constituting the MFI zeolite structure can be identified by NMR analysis.

6 and 7, gallium substituted in the MFI zeolite structure shows a peak at a position of about 150 ppm on ⁷¹ Ga-NMR, and aluminum constituting the MFI zeolite structure is at a position of about 50 ppm on ^{27 Al-NMR.} Shows a peak at. meso-GAS x:y catalyst and micro-GAS x:yThe catalyst showed a ^{peak at about 150 ppm on 71} Ga-NMR, indicating that the galoaluminosilicate was successfully prepared. In addition, it can be seen from the intensity of the peak that the galloalunosilicate was produced in the intended Al:Ga ratio. The GaOy/meso-HZSM-5 catalyst shows ^{no peak on 71} Ga-NMR, indicating that gallium is located outside the MFI zeolite structure.

8 and 9, the entire ammonia desorption curve can be divided into two curves, a curve between 150 and 300 degrees represents an ammonia desorption curve due to a weak acid point, and a curve between 300 and 500 degrees is a strong acid point. The ammonia desorption curve by is shown. A weak acid point means Lewis acid, and a strong acid point means Bronsted-Lowry acid.

Table 2 shows the results of an elevated temperature ammonia adsorption and desorption experiment of the meso-GAS x:y catalyst according to the examples of the present invention and the micro-GAS x:y catalyst according to the comparative examples and the GaOy/meso-HZSM-5 catalyst, and each acid point Represents a numerical value for the acid amount of

Referring to Table 2, the total acid amount of the meso-GAS catalyst and the micro-GAS catalyst is in the range of 1638 to 1922 μmol-NH3/gcat, of which 59.3 to 67.9% appear as Bronsted-Lowry acid sites. When comparing the meso-GAS 6:1 catalyst with the same gallium content and the GaOy/meso-HZSM-5 catalyst, the acid amount of the meso-GAS 6:1 catalyst is larger. Also, the proportion of the Bronsted-Lowry scattered points is larger. In other words, the meso-GAS catalyst has better acid properties than the catalyst supporting gallium on HZSM-5, and the Bronsted-Lowry acid site is located inside the MFI zeolite structure without blocking the Bronsted-Lowry acid site of the zeolite. The ratio of is also improved.

[Table 2]

[Example 2: Preparation of BTX by propane dehydrogenation aromatication reaction using galoaluminosilicate catalyst]

BTX was prepared by performing a propane dehydrogenation aromatication reaction at a reaction temperature of 550°C using a meso-GAS catalyst and a micro-GAS catalyst. The composition of the gas used in this example is nitrogen:propane = 12.5:0.5, and the total gas hourly space velocity (GHSV) is 3900ml/g-catalyst h. 0.2 g of the catalyst was charged into a quartz reactor, the temperature was raised to the reaction temperature at a rate of 11° C./min in a nitrogen atmosphere, and after reaching the reaction temperature, propane was passed through the catalyst layer to perform a dehydrogenation aromatication reaction. In this example, the conversion and yield of the reactants were calculated by the following

equations

1, 2, and 3, respectively.

[Equation 1]

[Equation 2]

[Equation 3]

10 and 11, when comparing the meso-GAS catalyst and the micro-GAS catalyst, when the molar ratio of Al:Ga is 6:1 and 1:6, the meso-GAS catalyst is more than the micro-GAS catalyst. In the case of a catalyst with a high yield of 4:3, the opposite was observed. That is, when one element of aluminum and gallium is dominant, the structural properties improved by the carbon template material are helpful for activation. It was found that the meso-GAS 6:1 catalyst showing good activity with a low gallium content was most suitable for propane dehydroaromatization reaction. The GaOy/meso-HZSM-5 catalyst, in which gallium is not substituted in the MFI structure, does not have high aromatization activity, whereas the meso-GAS 6:1 catalyst increases the activity with only a small amount of substituted gallium.

Table 3 shows the conversion rate and product selectivity of the meso-GAS 6:1 catalyst having excellent propane dehydrogenation aromatication activity even with a small gallium content among the galoaluminosilicate catalysts in the initial reaction (0.75 hours) and late reaction (13.5 hours). . The meso-GAS 6:1 catalyst showed a high conversion rate of 83.9% even after 13.5 hours reaction, and the BTX selectivity also did not change significantly.

[Table 3]

[Analysis Example 2: Comparison of meso-GAS 6:1 catalyst and GaO _y /meso-HZSM-5 catalyst in the production of BTX by propane dehydrogenation aromatication]

Under the same conditions as in the propane dehydroaromatization reaction of Example 2, a dehydroaromatic reaction of propane was performed using a meso-GAS 6:1 catalyst having the same gallium content and a GaOy/meso-HZSM-5 catalyst.

12 and 13, the meso-GAS 6:1 catalyst exhibits higher propane conversion and BTX yield than the _{GaO y /meso-HZSM-5 catalyst.} In the propane dehydrogenation aromatization reaction, both the acid point and structural properties of the catalyst play an important role. The reactant propane is activated by the Lewis acid site of the catalyst to form an intermediate, and the intermediates are converted to aromatics by the Bronsted-Lowry acid site. The produced aromatic escapes through the pores of the catalyst. When having the same gallium content, the meso-GAS catalyst exhibits better activity in the propane dehydroaromatization reaction because the acid and structural properties are better than _{that of the GaO y /meso-HZSM-5 catalyst.}

So far, specific examples of the present invention have been looked at. Those of ordinary skill in the art to which the present invention pertains will be able to understand that the present invention may be implemented in a modified form without departing from the essential characteristics of the present invention. Therefore, the disclosed embodiments should be considered from an illustrative point of view rather than a limiting point of view. The scope of the present invention is shown in the claims rather than the above description, and all differences within the scope equivalent thereto should be construed as being included in the present invention.

Claims

Forming a precursor solution comprising a silicon precursor, an aluminum precursor, a gallium precursor, and a carbon template material; And

A method of producing a galloaluminosilicate catalyst comprising the step of crystallizing the precursor solution to form a galloaluminosilicate catalyst.
The method of claim 1,

The step of forming the galloaluminosilicate catalyst,

Forming a first galloaluminosilicate by performing a crystallization process on the precursor solution,

Removing a carbon template material by performing a first firing process on the first galoaluminosilicate,

Adding the first galloaluminosilicate to an ion exchange solution to perform ion exchange to form a second galloaluminosilicate, and

And performing a second firing process on the second galloaluminosilicate.
The method of claim 1,

The silicon precursor comprises tetraethyl orthosilicate,

The aluminum precursor includes sodium aluminate,

The gallium precursor is a method of producing a galloaluminosilicate catalyst, characterized in that it contains gallium nitrate.
The method of claim 3,

The precursor solution further comprises sodium hydroxide and terpopropylammonium bromide.
As a galoaluminosilicate catalyst prepared by the method of any one of claims 1 to 4,

A gallium aluminosilicate catalyst, characterized in that a gallium atom is located in the crystal of the galloaluminosilicate catalyst.
The method of claim 5,

A galoaluminosilicate catalyst, characterized in that the molar ratio of aluminum:gallium is 10:1 to 1:10.
The method of claim 5,

The galloaluminosilicate catalyst is a galloaluminosilicate catalyst, characterized in that it has mesopores.
Filling the reactor with the galloaluminosilicate catalyst of claim 5;

Raising the temperature of the reactor to a reaction temperature; And

BTX manufacturing method comprising the step of performing a dehydrogenation aromatication reaction by providing a fronpan to the reactor.
The method of claim 8,

BTX manufacturing method, characterized in that the step of raising the temperature of the reactor is carried out under a nitrogen atmosphere.
The method of claim 8,

The reaction temperature is 500 ~ 600 ℃ BTX manufacturing method, characterized in that.