An acid complex cobalt iron bimetal modified hydrogen type mordenite zeolite catalyst, a preparation method and application thereof

Abstract

The present application belongs to the technical field of molecular sieve catalysts, and discloses a hydrogen-type mordenite catalyst modified by acid complex cobalt-iron bimetal and pyrazole tartrate, and a preparation method and application thereof.The preparation method comprises the following steps: (1) adding powdered ammonia-type mordenite into an acid complex cobalt-iron bimetal salt aqueous solution, stirring, performing ion exchange, and then roasting to obtain hydrogen-type mordenite modified by acid complex cobalt-iron; and (2) adding the hydrogen-type mordenite modified by acid complex cobalt-iron into a pyrazole tartrate solution, stirring, and performing ion exchange to obtain the catalyst.The catalyst has the advantages of simple preparation process, low cost, and no use of expensive noble metals, and can be used in the process of catalyzing dimethyl ether (DME) carbonylation to prepare methyl acetate (MA), and the dimethyl ether conversion rate can still be maintained at about 70% after 350 hours of reaction, the MA selectivity is greater than 99.99%, and the catalyst has good activity, selectivity and stability.

Description

Technical Field

[0001] This invention belongs to the field of molecular sieve catalyst technology, and specifically relates to a hydrogen-type mordenite catalyst modified with acid-complexed cobalt-iron bimetallic and pyrazole tartrate, its preparation method and application. Background Technology

[0002] High oil prices, energy shortages, and increasingly serious environmental problems have made the development of green and environmentally friendly alternative energy sources a pressing issue for countries worldwide. Ethanol, as an important chemical raw material and green fuel, is one of the most promising fossil fuel alternatives with broad application prospects. my country's existing ethanol production processes mainly include the biomass route of sugar or cellulose fermentation and the petroleum route of ethylene hydration. The biomass fermentation method primarily uses crops such as sugarcane, wheat, cassava, and corn as raw materials, but ethanol production via fermentation can easily lead to potential food crises or competition with the food supply chain, which is not in line with long-term sustainable development plans. The ethylene hydration method mainly includes indirect and direct methods. The indirect method has been phased out due to problems such as equipment corrosion and complex processes. The direct method also faces challenges such as demanding reaction conditions (reaction pressure around 7 MPa, temperature around 280℃) and low ethylene conversion rates. Furthermore, the ethylene-to-ethanol production route is also affected by oil supply and international prices, resulting in significant cost fluctuations. my country is rich in coal resources, and the development of coal chemical industry provides abundant syngas feedstock. Synthesizing ethanol from syngas is not only cost-effective but also achieves efficient utilization of coal resources, reducing harmful emissions from direct coal combustion. Syngas-to-ethanol production mainly includes methanol homologation, direct syngas synthesis, and the hydrogenation of syngas with acetyl groups such as methyl acetate. Among these methods, the production route of syngas carbonylating to methyl acetate (MA) and then hydrogenating to ethanol has advantages such as high atom utilization and mild reaction conditions, and has broad industrial application prospects. MA hydrogenation to ethanol is already very mature industrially. The main challenge in syngas-to-ethanol production via DME lies in the development of highly active and stable catalysts for the carbonylation of DME to MA.

[0003] Currently, the main solid acid catalysts developed for DME carbonylation are heteropoly acids and zeolite molecular sieves. Among them, hydrogen mordenite (HMOR) has a unique pore structure and acid properties, which not only have excellent DME carbonylation activity and selectivity, but also avoid the use of noble metals, corrosive acids and iodides in the reaction.

[0004] A key problem facing HMOR catalysts is the rapid deactivation of the 12-membered ring (12-MR) of HMOR during the reaction process due to severe carbon deposition. To improve the activity and stability of HMOR, researchers generally use inorganic bases, organic bases, and metals to modify the 8-membered ring (8-MR) or 12-MR in HMOR and improve the acidity of the catalyst pore surface. Wang et al. (The Journal of Physical Chemistry C, 2015, 119: 524-533.) modified HMOR with transition metals such as Ni, Co, Cu, Zn, and Ag via ion exchange. Cu-HMOR and Co-HMOR exhibited extremely high DME carbonylation conversion and MA selectivity, but their improvement on catalyst stability was minimal. Liu et al. (Catalysis Science & Technology, 2015, 5: 1961-1968) synthesized iron-modified HMOR through template-free in-situ hydrothermal synthesis and found that Fe... 3+ The introduction of [a specific substance] reduces the number and intensity of acidic sites within the 12-MR channels, inhibiting side reactions and coke formation during the DME carbonylation reaction, improving the selectivity of MA, and enhancing the activity and stability of HMOR. However, the high iron content and non-framework iron species can lead to partial blockage of the molecular sieve channels, resulting in a decrease in the DME conversion rate of the HMOR catalyst. Shen Wenjie et al. (Catalysis Science & Technology, 2018, 8:2124-2130) found that Co [a specific substance]... 2+ Co can be uniformly dispersed in HMOR, located in 8-MR channels 2+ It can promote the adsorption of CO and DME molecules, thereby increasing the reactivity; while Co located in the 12-MR channels 2+This can reduce the number of Brønsted acid sites in the pores and inhibit coke formation. Liu Zhongmin et al. (Catalysis Science & Technology, 2020, 10: 4663-4672) used aliphatic amines to selectively exchange ions with the Brønsted acid protons of the twelve-membered ring in HMOR to cover the active center of the twelve-membered ring coking reaction, which effectively solved the coking problem. The catalyst achieved a DME conversion of 50%, MA selectivity close to 100%, and a service life of over 210 hours. However, due to the large volume of the selected aliphatic amines, the specific surface area of ​​the modified molecular sieve was only 1 / 10 of the original, which affected the catalyst activity to some extent. Liu Shiping et al. (Catalysis Communications, 2020, 147) used alkyl imidazoles such as 1,3-dimethylimidazolium to modify HMOR. The DME conversion was close to 70%, MA selectivity reached 100%, and good stability was observed. However, due to the low boiling point of imidazole compounds, the slow desorption of nitrogen-containing heterocyclic molecules led to the gradual deactivation of the catalyst. Shen Wenjie et al. (Authorization Announcement No.: CN101613274B) pretreated HMOR with NaOH, KOH, hydrochloric acid, nitric acid, etc., and then used pyridine organic amines for pre-adsorption. The basic pyridine molecules selectively entered the twelve-membered ring and reacted with Brønsted Brønsted acid, reducing the Brønsted acid sites while preserving the acidic sites of the eight-membered ring, significantly extending the catalyst's lifespan. However, this method also suffers from problems such as in-situ carbonization of pyridine at high temperatures, and the DME conversion rate is relatively low (<30%). Liu Hongchao et al. (Authorization Announcement No.: CN106890671B) used pyridine compounds to purge acid-treated ENT zeolite, achieving a lifespan exceeding 3000 hours. The DME conversion rate of some catalysts reached as high as 49.8%, but the DME conversion rate of most catalysts was below 30%, and the catalyst preparation process was complex. Dong Xinfa et al. (Authorization Announcement No.: CN113499795B) mixed hydrochloric acid with 2-methylimidazolium hydrochloride solution and ion-exchanged it with hydrogen-form mordenite to obtain a modified hydrogen-form mordenite catalyst. The catalyst's DME conversion rate was close to 60%, but its stability was only maintained for about 30 hours. Liu Yahua et al. (Patent Publication No.: CN108160100A) reacted pyridine with the Brønsted acid site of the 12-membered ring of HMOR, and then modified the 8-membered ring with metal salts such as Cu(NO3)2 and Zn(NO3)2. The catalyst's stability was significantly improved, but the DME conversion rate was less than 50%. Wang Jinbang et al. (Patent Publication Nos.: CN107537549A, CN107537548A) used HMOR to pre-adsorb unsaturated hydrocarbons and nitrogen-containing heterocyclic compounds, and then carried out a high-temperature in-situ carbonization reaction to obtain a modified molecular sieve catalyst. Its DME conversion rate was high, but the catalyst's lifespan was only 24-47 hours.Dong Xinfa et al. (Patent Publication No.: CN116408146A) added a copper-modified hydrogen-form mordenite catalyst to a pyrazole phosphate solution for ion exchange, obtaining a copper- and pyrazole phosphate-modified hydrogen-form mordenite catalyst. The DME conversion rate of the catalyst was close to 60%, but it began to gradually decrease after 80 hours of reaction. This indicates that improving catalyst activity and stability, especially catalyst stability, remains a major challenge for HMOR carbonylation catalysts. Summary of the Invention

[0005] In order to overcome the shortcomings and deficiencies of the prior art, the present invention aims to provide an acid-complexed cobalt-iron bimetallic catalyst modified with pyrazole tartrate and its preparation method and application, so as to solve the problems of low activity and poor stability of HMOR catalysts.

[0006] This invention involves adding powdered ammoniacal mordenite (NH4MOR) to an acid-complexed aqueous solution of cobalt-iron bimetallic salt, stirring and performing ion exchange, followed by filtration, washing, drying, and calcination to obtain acid-complexed cobalt-iron modified hydrogen-form mordenite. The acid-complexed cobalt-iron modified hydrogen-form mordenite is then added to a pyrazole tartrate solution, stirred and performed ion exchange, followed by filtration, washing, and drying to obtain an acid-complexed cobalt-iron bimetallic and pyrazole tartrate modified hydrogen-form mordenite catalyst. The acid-complexed cobalt-iron bimetallic and pyrazole tartrate modified hydrogen-form mordenite catalyst of this invention exhibits high DME carbonylation activity, good selectivity, and good reaction stability. Furthermore, the preparation process is simple, the raw materials are inexpensive, and it eliminates the need for precious metals, highly corrosive acids, and iodides.

[0007] The objective of this invention can be achieved through the following solutions:

[0008] A method for preparing an acid-complexed cobalt-iron bimetallic catalyst modified with pyrazole tartrate, comprising the following steps:

[0009] (1) Powdered ammonia-type mordenite was added to an aqueous solution of cobalt-iron bimetallic salt that had been acid-complexed, stirred and subjected to ion exchange, then filtered, washed, dried and calcined to obtain acid-complexed cobalt-iron modified hydrogen-type mordenite.

[0010] (2) Add acid-complexed cobalt-iron modified hydrogen-type mordenite to pyrazole tartrate solution, stir to carry out ion exchange, then filter, wash and dry to obtain cobalt-iron bimetallic and pyrazole tartrate modified hydrogen-type mordenite catalyst.

[0011] Preferably, the mass ratio of the acid-complexed cobalt-iron modified hydrogen mordenite to the volume ratio of the pyrazole tartrate solution in step (2) is 1g:(15-30)ml, more preferably 1g:20ml.

[0012] Preferably, the concentration of the pyrazole tartrate solution in step (2) is 0.4 mol / L-1 mol / L, more preferably 0.6-0.8 mol / L, and most preferably 0.8 mol / L.

[0013] Preferably, the silica-alumina ratio of the powdered ammonia-type mordenite in step (1) is 15.

[0014] Preferably, the cobalt-iron bimetallic salt aqueous solution in step (1) is a mixed solution of cobalt nitrate and ferric nitrate.

[0015] Preferably, the mass ratio of the powdered ammonia-type mordenite to the volume ratio of the acid-complexed cobalt-iron bimetallic salt aqueous solution in step (1) is 1g:(15-30)ml, more preferably 1g:20ml.

[0016] Preferably, the cobalt-iron molar ratio in the cobalt-iron bimetallic salt aqueous solution in step (1) is 1:(0.5-2), more preferably 1:1.

[0017] Preferably, the concentration of the cobalt-iron bimetallic salt aqueous solution in step (1) is 0.1 mol / L-0.4 mol / L, more preferably 0.2 mol / L.

[0018] Preferably, the complexing agent for the acid-complexed cobalt-iron bimetallic salt aqueous solution in step (1) is one of tartaric acid, citric acid, oxalic acid and boric acid, more preferably tartaric acid.

[0019] The acid-complexed cobalt-iron bimetallic catalyst modified with pyrazole tartrate by the method described above is a hydrogen-type mordenite catalyst.

[0020] The above-mentioned acid-complexed cobalt-iron bimetallic catalyst modified with pyrazole tartrate hydrogen-form mordenite is used in the carbonylation of DME to produce MA. The reaction uses DME and CO as reactants, with a DME to CO molar ratio of 1:19; Ar or N2 is used as a diluent gas, with a diluent gas fraction of 20%; the reaction temperature is 185-230℃; the reaction pressure is 1-5 MPa; and the reaction space velocity is 2000-20000 ml·g. -1 ·h -1 .

[0021] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0022] In the catalyst preparation process of this invention, firstly through Co 2+ and Fe 3+The introduction of bimetals creates new Lewis acidic sites, significantly increasing the acidity and strength of HMOR, thereby substantially improving the conversion rate of DME. Secondly, during the catalyst preparation process of this invention, the acid complexation not only prevents the formation of metal agglomerates and potential partial blockage of molecular sieve channels and partial collapse of the framework, but also improves the Co content. 2+ and Fe 3+ The dispersion and exchange efficiency of metal ions. Furthermore, Co via acid complexation... 2+ and Fe 3+ Entering the 8-membered ring (8-MR) of HMOR, some Brønsted acid sites in the 8-MR can be converted into metal Lewis acid sites. Brønsted acid sites are conducive to DME carbonylation, while metal Lewis acid sites are conducive to CO binding. The synergistic catalytic effect of Brønsted acid sites and Lewis acid sites in the 8-MR channel effectively promotes the conversion rate of the DME carbonylation reaction and greatly improves the activity of the catalyst. At the same time, pyrazole tartrate, because its cation size is between that of 8-MR and 12-MR, can enter the 12-MR and exchange ions with Brønsted acid in the pores, but it is difficult to enter the 8-membered ring. It can retain Brønsted acid at the junction of 12-MR and 8-MR and Brønsted acid in the 8-MR. This invention uses pyrazole tartaric acid to modify HMOR. Compared with other pyrazole salts, tartaric acid has a higher boiling point, making it more difficult for the pyrazole tartaric acid cations that exchange ions with Brønsted acid in the 12-MR pores to desorb. This significantly slows down the desorption of pyrazole during the reaction, making it difficult for Brønsted acid to regenerate within the pores. This effectively suppresses the carbon deposition side reaction on the 12-MR pores, thereby improving the stability of the catalyst. The catalyst of this invention can be used for the carbonylation reaction of DME to produce MA. During a test time of 350 h, the dimethyl ether conversion remained at around 70%, the MA selectivity remained above 99.99%, and the DME conversion showed a gradual upward trend. Attached Figure Description

[0023] Figure 1 The graph shows the DME conversion rate of cobalt-iron bimetallic salt aqueous solution with different molar ratios (cobalt-iron modified HMOR15, pure cobalt modified HMOR15, pure iron modified HMOR15, and unmodified HMOR15) as a function of reaction time. The reaction conditions were: 215℃, 1.5MPa, GHSV = 4800 ml·g. -1 ·h -1 DME / CO / N2 = 1 / 19 / 5.

[0024] Figure 2The MA selectivity of HMOR15 modified with cobalt and iron at different molar ratios, pure cobalt modified HMOR15, pure iron modified HMOR15, and unmodified HMOR15 are plotted as a function of reaction time for a cobalt-iron bimetallic salt aqueous solution with a concentration of 0.2 mol / L. Reaction conditions: 215℃, 1.5 MPa, GHSV = 4800 ml·g -1 ·h -1 DME / CO / N2 = 1 / 19 / 5.

[0025] Figure 3 The graph shows the DME conversion rate of HMOR15 modified and unmodified with different concentrations of cobalt-iron bimetallic salt aqueous solutions at a cobalt-iron molar ratio of 1:1, as a function of reaction time. Reaction conditions: 215℃, 1.5MPa, GHSV = 4800 ml·g. -1 ·h -1 DME / CO / N2 = 1 / 19 / 5.

[0026] Figure 4 The graph shows the MA selectivity of HMOR15 modified and unmodified with different concentrations of cobalt-iron bimetallic salt aqueous solutions at a cobalt-iron molar ratio of 1:1. Reaction conditions: 215℃, 1.5MPa, GHSV = 4800 ml·g -1 ·h -1 DME / CO / N2 = 1 / 19 / 5.

[0027] Figure 5 The concentration of the cobalt-iron bimetallic salt aqueous solution was 0.2 mol / L, the cobalt-iron molar ratio was 1:1, and the DME conversion rate of HMOR15 modified with different acids (tartaric acid, citric acid, oxalic acid, boric acid) and HMOR15 with a concentration of 0.2 mol / L and a cobalt-iron molar ratio of 1:1 was plotted as a function of reaction time. Reaction conditions: 215℃, 1.5 MPa, GHSV = 4800 ml·g -1 ·h -1 DME / CO / N2 = 1 / 19 / 5.

[0028] Figure 6 The MA selectivity of HMOR15 modified with different acids (tartaric acid, citric acid, oxalic acid, and boric acid) with a concentration of 0.2 mol / L and a cobalt-iron molar ratio of 1:1, as well as the reaction time, is shown in the graphs. The reaction conditions were: 215℃, 1.5 MPa, GHSV = 4800 ml·g. -1 ·h -1DME / CO / N2 = 1 / 19 / 5.

[0029] Figure 7 Graph showing the DME conversion rate of HMOR15 modified with tartaric acid complexed with cobalt iron at different pyrazole tartrate solution concentrations as a function of reaction time; Reaction conditions: 215℃, 1.5MPa, GHSV = 4800 ml·g -1 ·h -1 DME / CO / N2 = 1 / 19 / 5.

[0030] Figure 8 MA selectivity of HMOR15 modified with tartaric acid complexed with cobalt iron at different pyrazole tartrate solution concentrations as a function of reaction time; Reaction conditions: 215℃, 1.5MPa, GHSV = 4800 ml·g -1 ·h -1 DME / CO / N2 = 1 / 19 / 5.

[0031] Figure 9 The figure shows the stability test results of the 0.2Co·Fe·DL-0.8Pya·DL-HMOR15(1:1) sample prepared in Example 4 after 350 h.

[0032] Explanation of abbreviations in the attached diagram:

[0033] NH4MOR15: Ammonia-type mordenite with a silica-alumina ratio of 15;

[0034] HMOR15: Hydrogen-type mordenite with a silica-to-alumina ratio of 15;

[0035] TOS: Reaction Time;

[0036] GHSV: Gas volume hourly space velocity;

[0037] Pyrazole tartrate: Pya·DL. Detailed Implementation

[0038] The present invention will be further described in detail below with reference to embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products.

[0039] Unless otherwise specified, all reagents used in the examples are commercially available.

[0040] Comparative Example 1

[0041] NH4MOR (silicon-to-aluminum ratio of 15, denoted as NH4MOR15) was placed in a muffle furnace and calcined at 500℃ for 3 hours at a rate of 3 K / min; the sample was denoted as HMOR15. 0.25 g of 40-60 mesh HMOR15 was then subjected to a carbonylation reaction in a fixed-bed reactor under the following conditions: 215℃, 1.5 MPa, GHSV = 4800 ml·g. -1 ·h -1 DME / CO / N2 = 1 / 19 / 5 (volume ratio), performance test results are available in [link to performance test results]. Figure 1 , Figure 2 .

[0042] Comparative Example 2

[0043] Take 2g of NH4MOR15 and add it to 40ml of 0.2mol / L Co(NO3)2 solution. Perform ion exchange for 3h under 80℃ water bath and stirring conditions. Filter, wash 3 times, dry in an oven at 110℃ overnight, calcine at 500℃ for 3h, compress into tablets and granulate. The sample is designated as Co-HMOR15. Take 0.25g of 40-60 mesh Co-HMOR15 and carry out DME carbonylation reaction in a fixed-bed reactor. Reaction conditions: 215℃, 1.5MPa, GHSV = 4800ml·g -1 ·h -1 DME / CO / N2 = 1 / 19 / 5, performance test results are shown below. Figure 1 , Figure 2 .

[0044] Comparative Example 3

[0045] Take 2g of NH4MOR15 and add it to 40ml of 0.2mol / L Fe(NO3)3 solution. Perform ion exchange for 3h under 80℃ water bath and stirring conditions. Filter, wash 3 times, dry in an oven at 110℃ overnight, calcine at 500℃ for 3h, compress into tablets and granulate. The sample is designated as Fe-HMOR15. Take 0.25g of 40-60 mesh Fe-HMOR15 and carry out DME carbonylation reaction in a fixed-bed reactor. Reaction conditions: 215℃, 1.5MPa, GHSV = 4800ml·g -1 ·h -1 DME / CO / N2 = 1 / 19 / 5, performance test results are shown below. Figure 1 , Figure 2 .

[0046] Example 1

[0047] 2g of NH4MOR15 was added to 40ml of 0.2mol / L cobalt-iron bimetallic salt aqueous solutions with cobalt-iron molar ratios of 1:1.5, 1:2, 2:1, and 1:1, respectively. Ion exchange was performed for 3 hours in an 80℃ water bath with stirring. The solutions were then filtered, washed three times, dried overnight at 110℃ in an oven, calcined at 500℃ for 3 hours, and granulated into tablets. The samples were designated as Co·Fe-HMOR15(1:1.5), Co·Fe-HMOR15(1:2), Co·Fe-HMOR15(2:1), and Co·Fe-HMOR15(1:1), where the ratios in parentheses represent the cobalt-iron molar ratio in the cobalt-iron bimetallic salt aqueous solutions during preparation. 0.25g of 40-60 mesh samples were then subjected to DME carbonylation in a fixed-bed reactor under the following conditions: 215℃, 1.5MPa, GHSV = 4800ml·g. -1 ·h -1 DME / CO / N2 = 1 / 19 / 5, performance test results are shown below. Figure 1 , Figure 2 .

[0048] Example 2

[0049] Take 2g of NH4MOR15 and add it to 40ml of 0.1mol / L, 0.2mol / L, 0.3mol / L, and 0.4mol / L cobalt-iron molar ratio aqueous solutions of cobalt-iron bimetallic salts with a concentration of 1:1. Ion exchange is carried out for 3h under 80℃ water bath and stirring. After filtration and washing three times, the samples are dried overnight at 110℃ in an oven and calcined at 500℃ for 3h. The samples are then compressed into tablets and granulated. The samples are recorded as 0.1Co·Fe-HMOR15(1:1), 0.2Co·Fe-HMOR15(1:1), 0.3Co·Fe-HMOR15(1:1), and 0.4Co·Fe-HMOR15(1:1). The ratio in parentheses represents the cobalt-iron molar ratio in the cobalt-iron bimetallic salt aqueous solution during the preparation process, and the number before Co·Fe represents the concentration of the cobalt-iron bimetallic salt aqueous solution during the preparation process. 0.25 g of 40-60 mesh sample was taken and subjected to DME carbonylation reaction in a fixed-bed reactor. The reaction conditions were: 215℃, 1.5 MPa, GHSV = 4800 ml·g. -1 ·h -1 DME / CO / N2 = 1 / 19 / 5, performance test results are shown below. Figure 3 , Figure 4 .

[0050] Example 3

[0051] Add 0.008 mol of tartaric acid (DL), citric acid (CA), oxalic acid (EA), and boric acid (BA) to 40 ml of a 0.2 mol / L cobalt-iron bimetallic salt aqueous solution with a cobalt-iron molar ratio of 1:1, and stir to dissolve to obtain an acid-complexed cobalt-iron bimetallic salt aqueous solution. Take 2g of NH4MOR15 and add it to 40ml of a cobalt-iron bimetallic salt aqueous solution that has been complexed with tartaric acid (DL), citric acid (CA), oxalic acid (EA), and boric acid (BA). Ion exchange is carried out for 3h in an 80℃ water bath with stirring. After filtration and washing three times, the sample is dried overnight at 110℃ in an oven and calcined at 500℃ for 3h. The sample is then compressed into tablets and granulated. The samples are recorded as 0.2Co·Fe·DL-HMOR15(1:1), 0.2Co·Fe·CA-HMOR15(1:1), 0.2Co·Fe·EA-HMOR15(1:1), and 0.2Co·Fe·BA-HMOR15(1:1). The ratio in parentheses represents the molar ratio of cobalt to iron in the cobalt-iron bimetallic salt aqueous solution during the preparation process, and the number before Co·Fe represents the concentration of the cobalt-iron bimetallic salt aqueous solution during the preparation process. 0.25 g of 40-60 mesh sample was taken and subjected to DME carbonylation reaction in a fixed-bed reactor. The reaction conditions were: 215℃, 1.5 MPa, GHSV = 4800 ml·g. -1 ·h -1 DME / CO / N2 = 1 / 19 / 5, performance test results are shown below. Figure 5 , Figure 6 .

[0052] Example 4

[0053] Pyrazole was added to tartaric acid to prepare a pyrazole tartrate (Pya·DL) solution of a certain concentration. 2g of 0.2Co·Fe·DL-HMOR15 (1:1) (sample preparation method see Example 3) was added to 40ml of each solution. Ion exchange was performed for 3 hours in 0.4 mol / L, 0.6 mol / L, 0.8 mol / L, and 1.0 mol / L Pya·DL solutions under 80℃ water bath and stirring conditions. The samples were filtered, washed three times, dried overnight in an oven at 110℃, and then compressed into tablets. The samples were recorded as 0.2Co·Fe·DL-0.4Pya·DL-HMOR15(1:1), 0.2Co·Fe·DL-0.6Pya·DL-HMOR15(1:1), 0.2Co·Fe·DL-0.8Pya·DL-HMOR15(1:1), and 0.2Co·Fe·DL-1.0Pya·DL-HMOR15(1:1). The ratio in parentheses represents the molar ratio of cobalt to iron in the cobalt-iron bimetallic salt aqueous solution during the preparation process. The number before Co·Fe represents the concentration of the cobalt-iron bimetallic salt aqueous solution during the preparation process, and the number before Pya·DL represents the concentration of the pyrazole tartrate solution. 0.25 g of 40-60 mesh sample was taken and subjected to DME carbonylation reaction in a fixed-bed reactor. The reaction conditions were: 215℃, 1.5 MPa, GHSV = 4800 ml·g. -1 ·h -1 DME / CO / N2 = 1 / 19 / 5, performance test results are shown below. Figure 7 , Figure 8 .

[0054] Example 5

[0055] 0.25 g of 40-60 mesh 0.2Co·Fe·DL-0.8Pya·DL-HMOR15 (1:1) sample was subjected to DME carbonylation reaction in a fixed-bed reactor under the same reaction conditions as in Example 4, and a stability test was performed for 350 h. The test results are shown in […]. Figure 9 The results showed that 0.2Co·Fe·DL-0.8Pya·DL-HMOR15 (1:1) maintained good stability during the DME carbonylation reaction time of 350 h, and its DME conversion rate was still on a slow upward trend.

[0056] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a hydrogen-form mordenite zeolite catalyst modified with acid-complexed cobalt-iron bimetallic compounds and pyrazole tartrate, characterized in that, Includes the following steps: (1) Powdered ammonia-type mordenite was added to an aqueous solution of cobalt-iron bimetallic salt that had been acid-complexed, stirred, and subjected to ion exchange. Then, it was filtered, washed, dried, and calcined to obtain acid-complexed cobalt-iron modified hydrogen-type mordenite. (2) Add acid-complexed cobalt-iron modified hydrogen-form mordenite to pyrazole tartrate solution, stir, carry out ion exchange, then filter, wash and dry to obtain acid-complexed cobalt-iron bimetallic and pyrazole tartrate modified hydrogen-form mordenite catalyst. The mass ratio of the acid-complexed cobalt-iron modified hydrogen-type mordenite to the volume ratio of the pyrazole tartrate solution in step (2) is 1 g:(15-30) mL. The concentration of the pyrazole tartrate solution in step (2) is 0.6 mol / L-0.8 mol / L.

2. The method for preparing the acid-complexed cobalt-iron bimetallic catalyst modified with pyrazole tartrate according to claim 1, characterized in that: In step (1), the silica-to-alumina ratio of the powdered ammonia-type mordenite is 15; The cobalt-iron bimetallic salt aqueous solution mentioned in step (1) is a mixed solution of cobalt nitrate and ferric nitrate; The mass ratio of the powdered ammonia-type mordenite to the volume ratio of the acid-complexed cobalt-iron bimetallic salt aqueous solution in step (1) is 1 g: (15-30) mL.

3. The method for preparing the acid-complexed cobalt-iron bimetallic catalyst modified with pyrazole tartrate according to claim 1, characterized in that: The cobalt-iron molar ratio in the cobalt-iron bimetallic salt aqueous solution described in step (1) is 1:(0.5-2).

4. The method for preparing the acid-complexed cobalt-iron bimetallic catalyst modified with pyrazole tartrate according to claim 1, characterized in that: The concentration of the cobalt-iron bimetallic salt aqueous solution in step (1) is 0.1 mol / L - 0.4 mol / L.

5. The method for preparing the acid-complexed cobalt-iron bimetallic catalyst modified with pyrazole tartrate according to claim 1, characterized in that: In step (1), the complexing agent for the acid-complexed cobalt-iron bimetallic salt aqueous solution is one of tartaric acid, citric acid, oxalic acid, and boric acid.

6. The method for preparing the acid-complexed cobalt-iron bimetallic catalyst modified with pyrazole tartrate according to claim 1, characterized in that: The mass ratio of the powdered ammonia-type mordenite to the volume ratio of the acid-complexed cobalt-iron bimetallic salt aqueous solution is 1 g: 20 mL, the molar ratio of cobalt to iron in the cobalt-iron bimetallic salt aqueous solution is 1:1, the concentration of the cobalt-iron bimetallic salt aqueous solution is 0.2 mol / L, the complexing agent of the acid-complexed cobalt-iron bimetallic salt aqueous solution is tartaric acid, the mass ratio of the acid-complexed cobalt-iron modified hydrogen-type mordenite to the volume ratio of the pyrazole tartrate solution is 1 g: 20 mL, and the concentration of the pyrazole tartrate solution is 0.8 mol / L.

7. A hydrogen-type mordenite catalyst modified with acid-complexed cobalt-iron bimetallic compounds and pyrazole tartrate as described in any one of claims 1-6.

8. The application of the acid-complexed cobalt-iron bimetallic catalyst modified with pyrazole tartrate according to claim 7 in the carbonylation of dimethyl ether to produce methyl acetate, characterized in that, DME and CO were used as reactants, with a DME to CO molar ratio of 1:19; Ar or N2 was used as a dilution gas, with a dilution gas integral of 20%; the reaction temperature was 185-230℃; the reaction pressure was 1-5 MPa; and the reaction space velocity was 2000-20000 mL·g -1 ·h -1 .

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