WO2016145619A1 - Method for preparation of, and application of, mordenite having mesopores and micropores - Google Patents

Abstract

Provided are a method for synthesizing mordenite having mesopores and micropores, and a product and application thereof. The method comprises precrystallizing, at 50°C-120°C for not less than 2 hours, a mixture containing a templating agent, a silicon source, an alkali source, and water, then adding an aluminum source, and then crystallizing at 120°C-220°C for not less than 12 hours. The method does not require the addition of a mesoporous templating agent, and the obtained mordenite has both micropores and mesopores; the obtained mordenite has excellent performance in respect of adsorption and catalysis, and may be applied to dimethyl ether carbonylation reaction catalysts.

Description

Preparation method and application of mordenite with mesopores and micropores Technical field

The present application belongs to the field of chemistry and chemical industry, and in particular to a method for synthesizing mordenite having mesopores and micropores and an application thereof.

Background technique

Mordenite is a two-dimensional pore structure whose structure was determined by Meier in 1961. The pore structure of the molecular sieve consists of a twelve-membered ring channel of 0.67*0.70 nm and an eight-membered ring channel of 0.34*0.48 nm. Since the pores of the eight-membered ring are too small for many molecules to enter, it is generally considered that the mordenite is a one-dimensional pore molecular sieve. Due to the unique pore structure and acidity of mordenite, it has important applications in catalytic cracking, toluene disproportionation and transalkylation, aromatic alkylation, xylene isomerization, dimethyl ether carbonylation and the like.

However, in practical applications, the relatively narrow pore structure will restrict the diffusion of macromolecules such as aromatic hydrocarbons, which may cause catalyst deactivation. On the other hand, due to severe diffusion limitations, a large number of active sites are difficult to access, thereby seriously affecting the activity of the catalyst. Therefore, the preparation of mesoporous mordenite to improve the mass transfer performance of mordenite is of great value for improving the catalytic performance of the catalyst. At the same time, reducing the grain size can effectively shorten the diffusion path, contribute to the diffusion of reactants and products, and improve its catalytic performance. Therefore, the synthesis of nano-scale molecular sieves and molecular sieves containing mesopores is a hot research topic.

Summary of the invention

According to an aspect of the present application, there is provided a method for synthesizing a mordenite having mesopores and micropores, which has the advantages of simple process, easy separation, and easy industrialization on a large scale, and the mordenite synthesized by the method avoids The defects of single channel structure have broad application prospects in adsorption and catalysis.

The method for synthesizing mordenite having mesopores and micropores, characterized in that a mixture containing a templating agent R, a silicon source, an alkali source and water is precrystallized at 50 to 120 ° C for not less than 2 hours. Adding an aluminum source and crystallization at 120-220 ° C for not less than 12 hours, the mordenite having mesopores and micropores;

The templating agent R is selected from the group consisting of tetraethylammonium hydroxide (abbreviated as TEAOH), tetraethylammonium chloride (abbreviated as TEACl), tetraethylammonium bromide (abbreviated as TEABr), tetraethylammonium fluoride ( At least one of TEAF), tetraethylammonium iodide (abbreviated as TEAF), and hexamethyleneimine (abbreviated as HMI);

The alkali source is sodium hydroxide and/or potassium hydroxide.

Preferably, the method comprises at least the following steps:

a) Mixing the templating agent R, the silicon source, the alkali source and water to obtain a mixture I:

b) pre-crystallizing the mixture I obtained in step a) at 50-120 ° C for 2 to 12 hours to obtain a precursor II;

c) adding an aluminum source and water to the precursor II obtained in step b) to form a mixture III having the following molar ratio:

Al ₂ O ₃ /SiO ₂ = 0.01 to 0.25;

M ₂ O/SiO ₂ = 0.10 to 0.40, wherein M is Na and/or K;

H ₂ O/SiO ₂ = 20 to 100;

R / SiO ₂ = 0.01 ~ 0.50;

d) crystallization of the mixture III obtained in the step c) at 120 to 220 ° C for not less than 12 hours;

e) After the completion of the crystallization of the step d), the solid product is separated and dried to obtain the mordenite having mesopores and micropores.

In the mixture, the number of moles of silicon source is SiO ₂ , which is equal to the number of moles of silicon in the system; the number of moles of aluminum source is 1/2 of Al ₂ O ₃ , which is equal to 1/2 of the mole of aluminum in the system; microporous template agent R to the number of moles of moles of R per se; the number of moles of M ₂ O, an alkali metal M of all raw materials (silicon source, an aluminum source, an alkali source) contained in the metal oxide corresponding to the number of moles of M ₂ O It is equal to 1/2 of the moles of the alkali metal element M in all the raw materials.

The moisture in the feedstock is a two-part addition system in which a portion of the water is used alone to dissolve the aluminum source to produce an aluminum source solution, and the remaining water is mixed with a silicon source, sodium hydroxide (potassium), and templating agent R to form a mixture I. Those skilled in the art can select the distribution of the two portions of water according to actual operational requirements and specific aluminum source dissolution requirements.

As a preferred embodiment, the templating agent R in the step a) is hexamethyleneimine.

As a preferred embodiment, the templating agent R in the step a) is hexamethyleneimine.

Preferably, the lower limit of the molar ratio range of Al ₂ O ₃ /SiO ₂ in the mixture III of the step c) is selected from 0.01, 0.0125, 0.013, 0.015, 0.016, 0.02, 0.025, 0.03, and the upper limit is selected from 0.075, 0.10, 0.25. . Further preferably, the molar ratio of the mixture III of the step c) is Al ₂ O ₃ /SiO ₂ = 0.015 to 0.1.

Preferably, the lower limit of the molar ratio range of M ₂ O/SiO ₂ in the mixture III of the step c) is selected from 0.10, 0.15, 0.20, and the upper limit is selected from 0.27, 0.29, 0.33, 0.35, 0.36, 0.38, 0.40. Further preferably, the molar ratio M ₂ O/SiO ₂ in the mixture III of the step c) is from 0.2 to 0.33, wherein M is Na and/or K.

Preferably, the lower limit of the molar ratio range of H ₂ O/SiO ₂ in the mixture III of the step c) is selected from 20, 30, 40, and the upper limit is selected from the group consisting of 50, 55, 60, 70, 80, 90, 100. Further preferably, the molar ratio H ₂ O/SiO ₂ in the mixture III of the step c) is 30 to 60.

Preferably, the lower limit of the molar ratio range of R/SiO ₂ in the mixture III of the step c) is selected from the group consisting of 0.01, 0.02, 0.03, 0.04, 0.06, and 0.08, and the upper limit is selected from the group consisting of 0.24, 0.27, 0.28, 0.30, 0.45, and 0.50. Further preferably, the molar ratio R/SiO ₂ of the mixture III of the step c) is 0.02 to 0.45. Still more preferably, the molar ratio R/SiO ₂ in the mixture III of the step c) is from 0.03 to 0.30.

Preferably, the step c) first dissolving the aluminum source in water to obtain a solution IV, and then adding the solution IV to the precursor II in the step b) and stirring, to form the following molar Proportioned mixture III:

Al ₂ O ₃ /SiO ₂ = 0.01 to 0.25;

M ₂ O/SiO ₂ = 0.10 to 0.40, wherein M is Na and/or K;

H ₂ O/SiO ₂ = 20 to 100;

R/SiO ₂ = 0.01 to 0.50.

The H ₂ O/SiO ₂ ratio in the mixture III is the total amount of water and the molar ratio of SiO ₂ . In the technical solution of the present application, the two parts are added to the system, and the first part is the mixing of the raw materials in the step a); The second part is the step c) water for dissolving the aluminum source. The amount of water used in the second part is determined by the dissolution of the aluminum source. Those skilled in the art can determine the appropriate amount of water in the step c) according to the actual source of aluminum and the amount thereof, in order to completely dissolve the aluminum source. The amount of water in the first portion can then be obtained based on the total amount of water in the target mixture in mixture III. Preferably, in step c) the molar ratio of water to SiO ₂ in solution IV is H ₂ O/SiO ₂ = 3-15.

Preferably, the silicon source in the step a) is at least one selected from the group consisting of silica sol, silicone gel, methyl orthosilicate, tetraethyl orthosilicate, white carbon, and water glass.

Preferably, the aluminum source in the step c) is at least one selected from the group consisting of aluminum isopropoxide, aluminum oxide, aluminum hydroxide, aluminum chloride, aluminum sulfate, aluminum nitrate, and sodium aluminate.

Preferably, the lower limit of the pre-crystallization temperature range in the step b) is selected from the group consisting of 50 ° C, 60 ° C, 70 ° C, 80 ° C, 90 ° C, and 100 ° C, and the upper limit is selected from 100 ° C, 110 ° C, and 120 ° C.

Preferably, the lower limit of the time range of the pre-crystallization in the step b) is selected from 2 hours, 4 hours, and 6 hours, and the upper limit is selected from 6 hours, 8 hours, 10 hours, and 12 hours. Further preferably, the step b) is pre-crystallized for 2 to 12 hours.

Preferably, the lower limit of the crystallization temperature range in the step d) is selected from the group consisting of 120 ° C, 125 ° C, and 130 ° C, and the upper temperature range is selected from the group consisting of 145 ° C, 150 ° C, 155 ° C, 160 ° C, 170 ° C, 178 ° C, 180 °C, 200 ° C, 220 ° C. Further preferably, the crystallization temperature in the step d) is from 125 to 180 °C.

Preferably, the lower limit of the time range for crystallization in the step d) is selected from 12 hours and 24 hours, and the upper limit is selected from the group consisting of 120 hours, 144 hours, 150 hours, 168 hours, and 216 hours. Further preferably, the crystallization time in the step d) is 12 to 168 hours.

Preferably, in the mordenite having mesopores and micropores, the mesopores have a pore diameter of 5 to 40 nm.

Preferably, in the mordenite having mesopores and micropores, the pore volume ratio of mesopores to micropores is from 1 to 4.7:1.

Preferably, the manner of crystallization in the step b) and/or the step c) may be static crystallization or dynamic crystallization.

In the present application, the term "static crystallization" means that during the crystallization, the kettle containing the initial gel mixture is placed in an oven and the mixture in the synthesis kettle is not stirred.

In the present application, the term "dynamic crystallization" means that the synthesis kettle containing the initial gel mixture is in a non-stationary state during crystallization, such as inversion, rotation, etc.; or in the crystallization process, the mixture inside the synthesis kettle Stir.

After the step c) is dried, it is calcined to obtain a mordenite containing both micropores and mesopores.

Preferably, the molecular sieve silica-alumina molar ratio obtained by the technical solution of the present application is SiO ₂ /Al ₂ O ₃ = 4 to 70.

According to still another aspect of the present application, there is provided a mordenite having mesopores and micropores, the mordenite being a nanoparticle having a large outer specific surface area while avoiding defects of a single pore structure, in adsorption and Catalyst has broad application prospects. The mordenite having mesopores and micropores is prepared by any of the above methods.

Preferably, the mordenite has an external specific surface area of from 100 m ² /g to 160 m ² /g.

Preferably, the mordenite has mesopores having a pore diameter of 5 nm to 40 nm.

Preferably, in the mordenite, the pore volume ratio of mesopores to micropores is from 1 to 4.7.

According to still another aspect of the present application, there is provided a mordenite having mesopores and micropores prepared according to any of the above methods and/or a mordenite having mesopores and micropores according to any of the above, in adsorption separation and/or Application in catalytic reactions.

According to still another aspect of the present application, there is provided a dimethyl ether carbonylation catalyst having the advantages of high conversion of dimethyl ether, high selectivity of methyl acetate, and long life, the catalysis The mordenite having mesopores and micropores prepared by any of the above methods and/or any of the above-mentioned mordenite having mesopores and micropores is obtained by ammonium ion exchange and calcination in air at 400 to 700 °C.

The beneficial effects that can be produced by this application include:

1) The preparation method of the mordenite provided by the present application has a simple process and is advantageous for large-scale industrial production.

2) The mordenite prepared according to the method provided by the present invention has micropores and mesopores, avoids defects of a single channel, and has broad application prospects in macromolecular adsorption and catalysis.

3) The mordenite prepared according to the method provided by the present application has obvious advantages in terms of diffusion and life as adsorbents and catalysts.

4) The mordenite prepared according to the method provided by the present invention has the advantages of high conversion rate, good selectivity and long life as a dimethyl ether carbonylation catalyst.

DRAWINGS

Figure 1 is an X-ray diffraction pattern of sample 1 ^# .

Figure 2 is a scanning electron micrograph of sample 1 ^# .

Figure 3 is a nitrogen physico-desorption desorption isotherm for sample 1 ^# .

4 is a scanning electron micrograph of sample D1 ^# in Comparative Example 1.

Figure 5 is a scanning electron micrograph of sample D2 ^# in Comparative Example 2.

detailed description

The present application is further described below in conjunction with specific embodiments. It is to be understood that the examples are not intended to limit the scope of the application.

Unless otherwise stated, the starting materials and catalysts in the examples of the present application were purchased commercially and used without any special treatment.

The analysis method in the embodiment of the present application is as follows:

The elemental composition was determined using a Philips Magix 2424X ray fluorescence analyzer (XRF).

X-ray powder diffraction phase analysis (XRD) was carried out using an X'Pert PRO X-ray diffractometer from the PANalytical Company of the Netherlands, a Cu target, a Kα radiation source (λ = 0.15418 nm), a voltage of 40 kV, and a current of 40 mA.

The scanning electron microscope (SEM) test was performed on a Hitachi SU8020 field emission scanning electron microscope with an acceleration voltage of 2 kV.

The pore structure of the sample was characterized by low temperature nitrogen physisorption, and the instrument used was Micromeritics ASAP2020 physical adsorption instrument.

Gas sample analysis was performed on-line using an Agilent 6890 GC gas chromatograph, which was an Agilent HP-5 capillary column.

Example 1: Preparation of Sample 1 ^#

First, 20 g of silica sol, 0.55 g of sodium hydroxide, 34.55 g of water and 0.59 g of tetraethylammonium hydroxide (TEAOH, 25%) were mixed, stirred, pre-crystallized at 50 ° C for 2 h, and then alumina acid was added dropwise thereto. An aqueous solution of sodium (0.467 g of sodium aluminate dissolved in 5.4 g of water) was stirred until a homogeneous gel formed. The gel was transferred to a stainless steel reaction vessel with a PTFE liner and crystallized at 130 ° C for 168 h. The obtained solid product was centrifuged, washed with deionized water to neutrality, dried at 110 ° C in air, and dried. Finally, it was calcined at 550 ° C for 6 h in a muffle furnace to obtain a nano mordenite having mesopores and micropores, which was designated as sample 1 ^# . Sample ^# 1 gel prepared in the ratio and type of feedstock, the pre-crystallization temperature and time, crystallization temperature and time were as shown in Table 1. Sample ^# 1 shown in FIG.

Examples 2 to 25: Preparation of Sample 2 ^# ～25 ^#

A silicon source (0.1 mol in terms of SiO ₂ ), water, sodium hydroxide (potassium), and a templating agent R were mixed and stirred uniformly to form a mixture I. The resulting mixture I was precrystallized to form a precursor II. The dissolved aluminum source aqueous solution (the aluminum source in Example 2 was dissolved in 27 g of water; the aluminum sources in Examples 3 to 25 were all dissolved in 10 g of water) was added to the precursor II, and stirred until a uniform initial gel mixture was formed. III. The mixture III was transferred to a PTFE-lined stainless steel reaction vessel for hydrothermal crystallization, and the obtained solid product was centrifuged, washed with deionized water to neutrality, dried at 110 ° C in air, and finally The nano mordenite having mesopores and micropores was obtained by calcination in a muffle furnace at 550 ° C for 6 h, and was designated as sample 2 ^# ～ 25 ^# . The raw material type and ratio, pre-crystallization temperature and time, crystallization mode, crystallization temperature and time in the initial gel mixture III of the prepared sample 2 ^# to 25 ^# are shown in Table 1, respectively.

Table 1 Molecular sieve synthesis ingredients and crystallization conditions table

^* Note: The silicon source: ^a silica sol; Silica ^{B; C} orthosilicate; ^D n-methyl silicate; silica gel ^{E; F} water glass.

Aluminum Source: sodium aluminate ^{Ⅰ; Ⅱ} aluminum chloride; ^Ⅲ aluminum hydroxide; aluminum sulfate ^{IV; Ⅴ} alumina; ^Ⅵ aluminum isopropoxide; ^VII aluminum nitrate.

Note ^**: Na ₂ O and K ₂ O is added for its ratio of an aluminum source, a silicon source and an alkali metal oxide source contained Na ₂ O and K ₂ O is calculated.

Comparative example 1

The specific steps, raw material ratio and experimental conditions are the same as those in the first embodiment, except that without pre-crystallization, the temperature is directly heated to 130 ° C, crystallization for 168 hours, and the obtained solid product is centrifuged and washed with deionized water to the middle. The product was dried in air at 110 ° C and finally calcined at 550 ° C for 5 h in a muffle furnace, and the obtained sample was recorded as sample D1 ^# .

Comparative example 2

The specific steps, raw material ratio and experimental conditions are the same as in the first embodiment, except that an aqueous solution of sodium aluminate (0.467 g of sodium aluminate dissolved in 10 g of water) is added dropwise before pre-crystallization, and stirred until uniformity is formed. The gel gel was placed in a stainless steel reaction vessel with a PTFE liner, pre-crystallized at 50 ° C for 2 h, and further crystallized at 130 ° C for 168 hours. The obtained solid product was centrifuged and washed with deionized water until Neutral, dried in air at 110 ° C, and finally calcined at 550 ° C for 5 h in a muffle furnace, and the obtained sample was recorded as sample D2 ^# .

Example 26: Silicon to aluminum ratio of sample 1 ^# ～25 ^# , D1 ^# and D2 ^#

XRF characterization was performed on samples 1 ^# to 25 ^# , D1 ^# and D2 ^# , and the elemental composition was determined, and the molar ratio of SiO ₂ /Al ₂ O _{3 was} calculated, as shown in Table 2.

Table 2 Sample 1 ^# ～25 ^# , D1 ^# and D2 ^# silicon-aluminum ratio

Example 27: XRD Characterization of Sample 1 ^# ～25 ^# , D1 ^# and D2 ^#

XRD characterization was performed on samples 1 ^# to 25 ^# , D1 ^# and D2 ^# . The XRD patterns of sample 1 ^# ～25 ^# , D1 ^# and D2 ^# are consistent with the characteristic spectra of standard mordenite zeolite molecular sieves, that is, the main diffraction peaks have the same position and shape, and the relative peak intensity is ±5% depending on the synthesis conditions. Fluctuations within the range indicate that samples 1 ^# to 25 ^# , D1 ^# and D2 ^# are both mordenite. A typical XRD pattern is represented by sample 1 ^# , as shown in Figure 1, and the XRD diffraction peak data are shown in Table 3.

Table 3 XRD diffraction peak data of sample 1 ^#

Peak number	2θ[°]	I/I 0 *100
			1	6.5153	34.09
2	8.6343	15.84
			3	9.7673	81.44
4	13.484	47.32
			5	13.882	25.84
6	14.6369	10.17
			7	15.2996	24.66
8	17.5842	1.92
			9	19.6458	45.45
10	21.0838	2.72
			11	21.4997	4.2
12	22.29	89.48
			13	23.2093	13.92
14	23.6732	13.76
			15	24.5671	3.68
16	25.6795	100
			17	26.3246	71.19
18	27.1554	9.72
			19	27.6522	48.61
20	27.904	50.61
			twenty one	28.3143	7.78
twenty two	28.721	5.05
			twenty three	30.4405	7.65
twenty four	30.9577	26.17
			25	33.2431	2.86
26	34.0683	2.03
			27	35.1127	6.04
28	35.677	15.01
			29	36.5319	5.3
30	36.973	3.7
			31	39.311	1.26
32	40.5253	3.1
			33	41.6509	0.88
34	42.7121	0.72
			35	44.342	7.52
36	44.9558	4.35
			37	45.5057	2.46
38	46.5543	8.44
			39	47.4486	3.6
40	48.5007	8.35
			41	50.4051	4.78

42	50.9485	4.56
			43	53.2869	2.04
44	54.1035	2.51

Example 28: Scanning electron microscopy characterization of sample 1 ^# ～25 ^# , D1 ^# and D2 ^#

Scanning electron microscopy characterization of samples 1 ^# ~25 ^# , D1 ^# and D2 ^# . The scanning electron micrograph shows that the morphology of sample 1 ^# ～25 ^# is the aggregation of spherical nanoparticles. A typical scanning electron microscope image is represented by sample 1 ^# . As can be seen from the figure, sample 1 ^# is an aggregate of small particles of 20 to 50 nm.

A scanning electron microscope image of sample D1 ^# is shown in FIG. As can be seen from the figure, the sample is a 20 um disc-shaped crystal.

A scanning electron microscope image of sample D2 ^# is shown in FIG. As can be seen from the figure, the sample is a disk-shaped crystal of 1 to 2 um.

Example 29: Characterization of pore structure of sample 1 ^# ～25 ^# , D1 ^# and D2 ^#

Pore structure characterization was performed on samples 1 ^# ~25 ^# , D1 ^# and D2 ^# using low temperature nitrogen physics. The adsorption desorption isotherms showed obvious hysteresis loops. The typical nitrogen adsorption desorption isotherms were represented by sample 1 ^#, as shown in Figure 3. The pore structure characterization results of sample 1 ^# ～ 25 ^# , D1 ^# and D2 ^# are shown in Table 4. Samples 1 ^# ～ 25 ^# both have larger mesoporous pore volume and micropore pore volume, ie sample 1 ^# ～ 25 ^# has mesopores and micropores. Samples D1 ^# and D2 ^# are predominantly microporous and contain almost no mesopores.

Table 4 Sample 1 ^# ～25 ^# , D1 ^# and D2 ^#孔结构characterization results

Example 30: Sample 1 ^# ～25 ^# , D1 ^# and D2 ^# for dimethyl ether carbonylation reaction

Samples 1 ^# ～25 ^# , D1 ^# and D2 ^# were separated by NH ₄ NO ₃ ion exchange to remove sodium ions, and calcined in air at 600 ° C for 4 h, then compressed and crushed to 40-60 mesh, respectively, as catalyst C1 ^# ～ C25 ^# , DC1 ^# and DC2 ^# . 1.0 g of catalysts C1 ^# C25 ^# , DC1 ^# and DC2 ^# were weighed separately, and dimethyl ether (abbreviated as DME) carbonylation reaction was evaluated in a fixed bed reactor. At the beginning of the reaction, the reaction was carried out by a nitrogen gas activation at 550 ° C for 1 h, followed by cooling to 200 ° C. The mixture gas (DME/CO/N ₂ = 2/14/84, volume ratio), the gas space velocity was 1500 ml g ^-1 h ^-1 (STP), and the reaction pressure was 2.0 MPa. After a 2 h induction period, samples were taken to obtain the conversion of DME and the selectivity of methyl acetate in the product. The catalysts C1 ^# to C25 ^# were all stable, and no significant deactivation occurred within 25 hours. The conversion rates and lifetimes of catalysts C1 ^# C25 ^# are generally higher than those of catalysts DC1 ^# and DC2 ^# . The conversion of DME, the selectivity of methyl acetate in the product, and the life of the catalyst are shown in Table 5, wherein the deactivation standard is that the conversion rate is reduced to 50% of the highest conversion.

TABLE 5 Sample 1 ^# ~ 25 ^#, D1 ^# D2 ^# dimethyl ether and the carbonylation reaction results

Catalyst number	DME conversion rate a	Methyl acetate selectivity b	Catalyst life c
				C1 #	62.1%	99.2%	30h
C2 #	67.8%	99.2%	25h
				C3 #	67.5%	99.3%	32h
C4 #	65.2%	98.2%	27h
				C5 #	68.8%	98.4%	28h
C6 #	67.1%	98.9%	29h
				C7 #	67.2%	98.2%	31h
C8 #	62.7%	99.1%	29h
				C9 #	64.3%	99.1%	28h
C10 #	65.1%	99.4%	27h
				C11 #	67.9%	99.0%	29h
C12 #	68.2%	98.7%	29h
				C13 #	65.1%	98.3%	27h
C14 #	63.1%	98.9%	28h
				C15 #	62.6%	98.8%	29h
C16 #	68.1%	99.0%	28h
				C17 #	62.8%	99.5%	30h
C18 #	66.4%	99.1%	28h
				C19 #	63.2%	98.5%	29h
C20 #	64.8%	99.0%	28h
				C21 #	65.8%	98.2%	29h
C22 #	69.1%	98.8%	27h
				C23 #	67.4%	99.3%	29h
C24 #	69.2%	99.0%	26h
				C25 #	65.2%	99.1%	29h
DC1 #	33.9%	96.2%	7h
				DC2 #	42.8%	97.8%	9h

Note: a: The highest conversion rate during the reaction.

b: selectivity of methyl acetate at the highest conversion rate during the reaction.

c: The time from the highest conversion rate to half the conversion rate of the highest conversion rate.

The above description is only a few examples of the present application, and is not intended to limit the scope of the application. However, the present application is disclosed in the preferred embodiments, but is not intended to limit the application, any person skilled in the art, It is within the scope of the technical solution to make a slight change or modification with the technical content disclosed above, which is equivalent to the equivalent embodiment, without departing from the technical scope of the present application.

Claims (10)

1. A method for synthesizing mordenite having mesopores and micropores, characterized in that a mixture containing a templating agent R, a silicon source, an alkali source and water is precrystallized at 50 ° C to 120 ° C for not less than 2 hours. , adding an aluminum source, and then crystallization at 120 ° C ~ 220 ° C for not less than 12 hours, that is, the mesoporous and microporous mordenite;

   The templating agent R is selected from the group consisting of tetraethylammonium hydroxide, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium fluoride, tetraethylammonium iodide, and hexamethyleneimine. At least one

   The alkali source is sodium hydroxide and/or potassium hydroxide.
2. The method of claim 1 including the steps of:

   a) mixing the templating agent R, the silicon source, the alkali source and water to obtain a mixture I;

   b) pre-crystallizing the mixture I obtained in step a) at 50 ° C ~ 120 ° C for 2 hours to 12 hours to obtain a precursor II;

   c) adding an aluminum source and water to the precursor II obtained in step b) to form a mixture III having the following molar ratio:

   Al ₂ O ₃ /SiO ₂ = 0.01 to 0.25;

   M ₂ O/SiO ₂ = 0.10 to 0.40, wherein M is Na and/or K;

   H ₂ O/SiO ₂ = 20 to 100;

   R / SiO ₂ = 0.01 ~ 0.50;

   d) crystallization of the mixture III obtained in the step c) at 120 ° C ~ 220 ° C for not less than 12 hours;

   e) after the completion of the crystallization of the step d), the solid product is separated, dried, and calcined, that is, the Mordenite with mesopores and micropores.
3. The method of claim 1 wherein said templating agent R is hexamethyleneimine.
4. The method according to claim 2, wherein the molar ratio R/SiO ₂ in the mixture III in the step c) is from 0.03 to 0.30.
5. The method according to claim 2, wherein said step c) first dissolving the aluminum source in water to obtain solution IV, and then adding said solution IV dropwise to said precursor II in step b) Stirring to form a mixture of the following molar ratios III:

   Al ₂ O ₃ /SiO ₂ = 0.01 to 0.25;

   M ₂ O/SiO ₂ = 0.10 to 0.40, wherein M is Na and/or K;

   H ₂ O/SiO ₂ = 20 to 100;

   R/SiO ₂ = 0.01 to 0.50.
6. The method according to claim 1, wherein the crystallization temperature in the step d) is from 125 ° C to 180 ° C.
7. The method according to claim 1, wherein the crystallization time in the step d) is from 12 hours to 168 hours.
8. A mordenite having mesopores and micropores prepared by the method according to any one of claims 1 to 7, wherein the mordenite has an external specific surface area of from 100 m ² /g to 160 m ² /g; The mordenite has mesopores having a pore diameter of 5 nm to 40 nm.
9. The mordenite according to claim 8, wherein the mordenite has a pore volume ratio of mesopores to micropores of from 1 to 4.7.
10. A dimethyl ether carbonylation catalyst characterized by the claims 1 to 7 The mordenite having mesoporous and microporous synthesized by any of the methods and/or the mordenite having mesopores and micropores according to claim 8 or 9 is subjected to ammonium ion exchange and calcination in air at 400 ° C to 700 ° C get.

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