A copper and pyrazole phosphate modified hydrogen-type mordenite catalyst and its preparation method and application

Abstract

The present invention belongs to the technical field of molecular sieve catalysts, and discloses a copper and pyrazole phosphate modified hydrogen-type mordenite catalyst and its preparation and application. The preparation method comprises: (1) adding powdered hydrogen-type mordenite to a copper salt aqueous solution, stirring for ion exchange, then filtering, washing, drying and calcining to obtain a copper-modified hydrogen-type mordenite catalyst; (2) adding the copper-modified hydrogen-type mordenite catalyst to a pyrazole phosphate solution, stirring for ion exchange, then filtering, washing and drying to obtain a copper and pyrazole phosphate modified hydrogen-type mordenite catalyst. The catalyst preparation process of the present invention is simple, low in cost, does not use expensive precious metals, can be used to catalyze the carbonylation of dimethyl ether (DME) to produce methyl acetate (MA), and has good activity, selectivity and stability.

Description

Technical Field

[0001] The invention belongs to the technical field of molecular sieve catalysts, and particularly relates to a hydrogen-type mordenite catalyst modified by copper and pyrazole phosphate, and a preparation method and application thereof. Background Art

[0002] The high oil prices, energy shortages and increasingly serious ecological and environmental problems have made the development of green and environmentally friendly alternative energy sources an urgent problem for countries around the world. Ethanol is considered to be a renewable energy source that can replace or improve conventional fossil fuels and has broad application prospects. At present, the industrial production method of ethanol is mainly obtained by fermentation using crops such as sugarcane, wheat, cassava, and corn as raw materials. However, the fermentation method for producing ethanol is likely to bring about a potential food crisis or competition with the food supply chain, and a new ethanol preparation process is urgently needed. my country has abundant coal resources, and the development of coal chemical industry provides abundant syngas raw materials. Therefore, the synthesis of ethanol from syngas is not only low-cost, but also realizes the efficient utilization of coal resources and reduces the emission of harmful substances caused by direct combustion of coal. The main methods of preparing ethanol from syngas include methanol homologation, direct synthesis of syngas, and hydrogenation of syngas via acetyl substances such as methyl acetate. Among them, the carbonylation of syngas to methyl acetate (MA) via dimethyl ether (DME) and then hydrogenation to ethanol have attracted widespread attention from engineering and academic researchers. The process route has mild reaction conditions, cheap and easy-to-obtain raw materials, is green and environmentally friendly, and can simultaneously solve the problems of methanol overcapacity and ethanol undercapacity. The hydrogenation of MA to ethanol is already very mature in industry. The main challenge in producing ethanol from synthesis gas via DME lies in the research and development of high-activity and high-stability DME carbonylation catalysts for producing MA.

[0003] Currently, the solid acid catalysts developed for DME carbonylation mainly include heteropoly acids and zeolite molecular sieves. Among them, hydrogen-type mordenite (HMOR) stands out among many molecular sieves due to its unique pore structure, which gives it excellent activity and selectivity. It avoids the use of precious metals, corrosive acids and iodides in the carbonylation reaction.

[0004] The key problem faced by HMOR as a dimethyl ether carbonylation catalyst is that 12-MR is severely carbonized and rapidly deactivated during the HMOR carbonylation reaction. In order to improve the activity and stability of HMOR, Wang et al. (The Journal of Physical Chemistry C, 2015, 119: 524-533.) modified HMOR by ion exchange using transition metals such as Ni, Co, Cu, Zn, and Ag, among which Cu-HMOR and Co-HMOR showed extremely high DME carbonylation conversion and MA selectivity, but the improvement of catalyst stability was minimal. Shen Wenjie et al. (patent authorization text CN101613274B) pre-treated HMOR with NaOH, KOH, etc. or hydrochloric acid, nitric acid, etc., and then used pyridine organic amine for pre-adsorption. The alkaline pyridine molecules selectively entered the twelve-membered ring and reacted with the Bronsted acid (B acid), reducing the B acid site, while the eight-membered ring acid site was preserved, significantly extending the service life of the catalyst. However, this method also has problems such as in-situ carbonization of pyridine at high temperatures, and the DME conversion rate is low (<30%). Liu Hongchao et al. (patent authorization text CN106890671B) used pyridine compounds to purge acid-treated ENT zeolite. The catalyst life exceeded 3000h, and the DME conversion rate of some catalysts was as high as 49.8%, but the DME conversion rate of most catalysts was less than 30%, and the catalyst preparation process was complicated. Wang Jingang et al. (patent publication CN107537549A, CN107537548A) used HNOR to pre-absorb unsaturated hydrocarbons and nitrogen-containing heterocyclic compounds, and then carried out high-temperature in-situ carbonization reaction to obtain a modified molecular sieve catalyst, which had a high DME conversion rate, but the catalyst service life was only 24-47h. Liu Yahua et al. (patent publication CN108160100A) used pyridine to react with the B acid site of the twelve-membered ring of HMOR, and then used metal salts such as Cu(NO3)2 and Zn(NO3)2 to modify the eight-membered ring, which significantly improved the stability of the catalyst, but the DME conversion rate was generally less than 50%. Liu Zhongmin et al. (Catalysis Science & Technology, 2020, 10: 4663-4672) used fatty amines to selectively exchange ions with the B acid protons of the twelve-membered ring in HMOR to cover the active center of the twelve-membered ring carbon deposition reaction, which effectively solved the carbon deposition problem. The DME conversion rate of the catalyst reached 50%, the MA selectivity was close to 100%, and the service life was more than 210 hours. However, due to the large volume of the selected fatty amine, the specific surface area of ​​the modified molecular decoration was only 1 / 10 of the original, and the catalyst activity was affected to a certain extent.Liu Shiping et al. (Catalysis Communications, 2020, 147) used alkyl imidazolium ions such as 1,3-dimethylimidazole to modify HMOR. The DME conversion rate was close to 70%, and the MA selectivity reached 100%, showing a certain stability. However, due to the low boiling point of the imidazole compounds used, the nitrogen-containing heterocyclic molecules slowly desorbed, causing the catalyst to gradually deactivate. Summary of the invention

[0005] In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, the primary purpose of the present invention is to provide a method for preparing a hydrogen-type mordenite catalyst modified by copper and pyrazole phosphate, so as to solve the problems of low activity, short life and high cost of HMOR catalyst. In the present invention, HMOR is first added to a copper nitrate solution and stirred evenly. 2+ Enter the 8-membered ring and perform ion exchange, so that part of the B acid sites therein are converted into metal L acid sites. The appropriate amount of B acid sites is conducive to the carbonylation of DME, and the metal L acid sites are conducive to the binding of CO, and cooperate with the B acid in the 8-membered ring channel to catalyze the carbonylation reaction of DME; and the pyrazole phosphate, because its cation size is between the 8-membered ring and the 12-membered ring, can enter the 12-membered ring to exchange ions with the B acid in the channel and some copper species, but it is difficult to enter the 8-membered ring, thereby retaining the B acid in the 8-membered ring and the exchanged copper species. In addition, the pyrazole phosphate cation that enters the 12-membered ring and exchanges ions with the B acid is difficult to desorb, which significantly reduces the B acid sites in the 12-membered ring channel, and the pyrazole phosphate can remove the CuO generated by roasting on the catalyst surface, thereby further improving the catalyst activity. Therefore, the catalyst of the present invention prevents the carbon deposition reaction of the HMOR12-membered ring while maintaining high activity in the dimethyl ether carbonylation reaction, thereby improving stability. The catalyst preparation process of the present invention is simple, the raw material price is low, and no precious metals, corrosive acids and iodides are used.

[0006] Another object of the present invention is to provide a hydrogen-type mordenite catalyst modified with copper and pyrazole phosphate prepared by the above method.

[0007] Another object of the present invention is to provide the use of the above copper and pyrazole phosphate modified hydrogen-type mordenite catalyst in the carbonylation of dimethyl ether to produce methyl acetate.

[0008] The purpose of the present invention is achieved through the following solutions:

[0009] A method for preparing a hydrogen-type mordenite catalyst modified by copper and pyrazole phosphate comprises the following steps:

[0010] (1) adding powdered hydrogen-type mordenite to a copper salt aqueous solution, stirring to perform ion exchange, and then filtering, washing, drying and calcining to obtain a copper-modified hydrogen-type mordenite catalyst;

[0011] (2) adding the copper-modified hydrogen-type mordenite catalyst into the pyrazole phosphate solution, stirring to carry out ion exchange, and then filtering, washing and drying to obtain the copper-pyrazole phosphate-modified hydrogen-type mordenite catalyst.

[0012] The silicon-aluminum ratio of the powdered hydrogen-type mordenite in step (1) is 10-25, preferably 15;

[0013] The copper salt described in step (1) is preferably at least one of copper nitrate, copper chloride and copper acetate, preferably copper nitrate.

[0014] The concentration of the copper salt aqueous solution in step (1) is 5.2-0.013 mol / L.

[0015] The temperature of the ion exchange in step (1) is 25-80° C., and the time of the ion exchange is 1-3 h.

[0016] The calcination temperature in step (1) is 350-550° C., the calcination time is 3 hours, and the calcination is carried out in air.

[0017] Preferably, the calcination temperature in step (1) is 450°C.

[0018] The concentration of the pyrazole phosphate solution in step (2) is 0.35 mol / L-3 mol / L, preferably 1.3 mol / L.

[0019] The pyrazole phosphate solution in step (2) is obtained by reacting phosphoric acid with pyrazole. The concentration of the obtained pyrazole phosphate solution can be adjusted by adding water.

[0020] In the preparation process of the copper and pyrazole phosphate modified hydrogen-type mordenite catalyst in steps (1) and (2), the ratio of hydrogen-type mordenite, copper salt and pyrazole phosphate is 1g:78mmol:13mmol-1g:0.195mmol:13mmol.

[0021] Preferably, in the preparation process of the copper and pyrazole phosphate modified hydrogen-type mordenite catalyst in steps (1) and (2), the molar ratio of the copper salt and pyrazole phosphate used for ion exchange is 6:1-3:200, more preferably 3:20-3:2.

[0022] The temperature of the ion exchange in step (2) is 25-80° C., and the time of the ion exchange is 1-3 h.

[0023] A hydrogen-type mordenite catalyst modified by copper and pyrazole phosphate prepared by the above method.

[0024] The copper and pyrazole phosphate modified hydrogen-type mordenite catalyst is used in the carbonylation of dimethyl ether to produce methyl acetate, wherein dimethyl ether and CO are used as reaction gases, the molar ratio of dimethyl ether to CO is 1:10-50; Ar gas or N2 gas is used as diluent gas, and the dilution gas volume fraction is 0-50%; the reaction temperature is 185-230°C; the reaction pressure is 1-5MPa, and the reaction space velocity is 2000-20000ml·g -1 ·h -1 .

[0025] The reaction temperature is preferably 230°C.

[0026] The reaction space velocity is preferably 3600 ml·g -1 ·h -1 .

[0027] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0028] The catalyst of the invention can be used for DME carbonylation reaction to prepare MA, has good carbonylation activity, selectivity and stability, and has a simple preparation process and low raw material price. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The DME conversion rate of HMOR15 modified by Cu and Pya·H3PO4, HMOR15 modified by Cu, HMOR15 modified by Pya·H3PO4 and unmodified HMOR varies with reaction time; reaction conditions: 215°C, 1.5MPa, GHSV=4800ml·g -1 ·h -1 , DME / CO / N2=1 / 19 / 5.

[0030] Figure 2 The MA selectivity of Cu and Pya·H3PO4 modified HMOR15, Cu modified HMOR15, Pya·H3PO4 modified HMOR15 and unmodified HMOR varies with reaction time; reaction conditions: 215℃, 1.5MPa, GHSV=4800ml·g -1 ·h -1 , DME / CO / N2=1 / 19 / 5.

[0031] Figure 3 The DME conversion rate of HMOR15 modified by different ratios of Cu and Pya·H3PO4 varies with reaction time; reaction conditions: 215℃, 1.5MPa, GHSV=4800ml·g -1 ·h -1 , DME / CO / N2=1 / 19 / 5.

[0032] Figure 4 The MA selectivity curve of HMOR15 modified with different ratios of Cu and Pya·H3PO4 varies with the ratio; reaction conditions: 215℃, 1.5MPa, GHSV=4800ml·g -1 ·h -1 , DME / CO / N2=1 / 19 / 5.

[0033] Figure 5 The DME conversion rate of HMOR15 modified by Cu and Pya·H3PO4 prepared at different calcination temperatures varies with reaction time; reaction conditions: 215℃, 1.5MPa, GHSV=4800ml·g -1 ·h -1 , DME / CO / N2=1 / 19 / 5.

[0034] Figure 6 The MA selectivity of HMOR15 modified by Cu and Pya·H3PO4 prepared at different calcination temperatures varies with reaction time; reaction conditions: 215℃, 1.5MPa, GHSV=4800ml·g -1 ·h -1 , DME / CO / N2=1 / 19 / 5.

[0035] Figure 7 The DME conversion rate of HMOR15 modified by Cu and Pya·H3PO4 varies with reaction time under different reaction temperature conditions; reaction conditions: 185℃ / 200℃ / 215℃ / 230℃, 1.5MPa, GHSV=4800ml·g -1 ·h -1 , DME / CO / N2=1 / 19 / 5.

[0036] Figure 8 The MA selectivity of HMOR15 modified by Cu and Pya·H3PO4 varies with the reaction temperature; reaction conditions: 185℃ / 200℃ / 215℃ / 230℃, 1.5MPa, GHSV=4800ml·g -1 ·h -1 , DME / CO / N2=1 / 19 / 5.

[0037] Fig. 9 The DME conversion rate of HMOR15 modified by Cu and Pya·H3PO4 varies with reaction time under different reaction space velocity conditions; reaction conditions: 215℃, 1.5MPa, DME / CO / N2=1 / 19 / 5, 3600ml·g -1 ·h -1 / 4800ml·g -1 ·h -1 / 6000ml·g -1 ·h -1 .

[0038] Fig.10 The MA selectivity of HMOR15 modified by Cu and Pya·H3PO4 varies with reaction time under different reaction space velocity conditions; reaction conditions: 215℃, 1.5MPa, DME / CO / N2=1 / 19 / 5, 3600ml·g -1 ·h -1 / 4800ml·g -1 ·h -1 / 6000ml·g -1 ·h -1 .

[0039] Fig.11 The DME conversion rate of HMOR15 modified by Cu and Pya·H3PO4 varies with reaction time under different ion exchange temperature conditions; reaction conditions: 215℃, 1.5MPa, GHSV=4800ml·g -1 ·h -1 , DME / CO / N2=1 / 19 / 5.

[0040] Fig.12 The MA selectivity of HMOR15 modified by Cu and Pya·H3PO4 varies with reaction time under different ion exchange temperature conditions; reaction conditions: 215℃, 1.5MPa, GHSV=4800ml·g -1 ·h -1 , DME / CO / N2=1 / 19 / 5.

[0041] Fig.13 The DME conversion rate of HMOR15 modified by Cu and Pya·H3PO4 varies with reaction time under different ion exchange conditions; reaction conditions: 215℃, 1.5MPa, GHSV=4800ml·g -1 ·h -1 , DME / CO / N2=1 / 19 / 5.

[0042] Fig.14 The MA selectivity of HMOR15 modified by Cu and Pya·H3PO4 varies with reaction time under different ion exchange conditions; reaction conditions: 215℃, 1.5MPa, GHSV=4800ml·g -1 ·h -1 , DME / CO / N2=1 / 19 / 5.

[0043] Fig.15This is a graph showing the stability test results of the Cu-Pya-HMOR15-550 (3:13) sample prepared in Example 1 after 100 hours.

[0044] Description of the abbreviations in the accompanying drawings:

[0045] HMOR15: hydrogen-type mordenite with a silicon-aluminum ratio of 15;

[0046] TOS: reaction time;

[0047] GHSV: gas phase volume space velocity;

[0048] Pyrazole phosphate: Pya·H3PO4. DETAILED DESCRIPTION

[0049] The present invention is further described in detail below in conjunction with the examples and drawings, but the embodiments of the present invention are not limited thereto. If specific conditions are not specified in the examples, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0050] Unless otherwise specified, the reagents used in the examples can be purchased from the market.

[0051] Comparative Example 1

[0052] HMOR (silicon-aluminum ratio of 15) was placed in a muffle furnace and calcined at 550°C at 3K / min for 3h. The sample was recorded as HMOR15-550, where 550 represents the calcination temperature. 0.25g of 40-60 mesh HMOR15-550 was taken and carbonylation reaction was carried out in a fixed bed reactor. The reaction conditions were: 215°C, 1.5MPa, GHSV = 4800ml·g -1 ·h -1 , DME / CO / N2=1 / 19 / 5 (volume ratio), performance test results see Figure 1 , Figure 2 .

[0053] Comparative Example 2

[0054] Take 2g HMOR15, add it to 30ml 0.2mol / L Cu(NO3)2 solution, ion exchange for 3h in 80℃ water bath with stirring, filter, wash 3 times, dry overnight at 110℃ in an oven, roast at 550℃ for 3h, press into tablets, and the sample is recorded as Cu-HMOR15-550, where 550 represents the roasting temperature. Take 0.25g 40-60 mesh Cu-HMOR15-550 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 see Figure 1 , Figure 2 .

[0055] Comparative Example 3

[0056] Add pyrazole to phosphoric acid to prepare a pyrazole phosphate solution of a certain concentration. Take 2g HMOR15 and add it to 20ml 1.3mol / L Pya·H3PO4 solution. Perform ion exchange for 3h in a water bath at 80℃ with stirring, filter, wash 3 times, dry overnight at 110℃ in an oven, press into tablets, and the sample is recorded as Pya-HMOR15-550, where 550 represents the calcination temperature. Take 0.25g 40-60 mesh Pya-HMOR15-550 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 see Figure 1 , Figure 2 As can be seen from the figure, the conversion rate of copper modification and pyrazole phosphate modification at the same time is significantly greater than the sum of the conversion rates of copper modification and pyrazole phosphate modification alone, indicating that after copper and pyrazole phosphate are modified at the same time, the two have a synergistic effect; in addition, after the use of pyrazole phosphate modification, its stability is also significantly improved, and its conversion rate does not decrease after 20 hours of reaction.

[0057] Example 1

[0058] Take 2g HMOR15 respectively and add it into 30ml Cu(NO3)2 solution with concentration of 5.2mol / L, 2.6mol / L, 1.3mol / L, 0.65mol / L, 0.33mol / L, 0.2mol / L, 0.13mol / L, 0.033mol / L and 0.013mol / L respectively. Perform ion exchange for 3h in 80℃ water bath with stirring, filter, wash 3 times, dry in an oven at 110℃ overnight, and calcine at 550℃ for 3h to obtain Cu-HMOR15-550 samples with different Cu contents. 2 g of the above Cu-HMOR15-550 sample was added to 20 ml of 1.3 mol / L Pya·H3PO4 solution, ion exchange was carried out in a water bath at 80°C with stirring for 3 h, filtered, washed 3 times, and the obtained sample was placed in an oven and dried overnight at 110°C, and pressed into tablets and granules. The samples were respectively recorded as Cu-Pya-HMOR15-550(6:1), Cu-Pya-HMOR15-550(3:1), Cu-Pya-HMOR15-550(3:2), Cu-Pya-HMOR15-550(3:4), Cu-Pya-HMOR15-550(3:8), Cu-Pya-HMOR15-550(3:13), Cu-Pya-HMOR15-550(3:20), Cu-Pya-HMOR15-550 (3:80) and Cu-Pya-HMOR15-550 (3:200), where 550 represents the calcination temperature and the ratio in brackets represents the molar ratio of copper nitrate to pyrazole phosphate used for ion exchange in the preparation process. 0.25g of 40-60 mesh samples were taken in a fixed bed reactor for DME carbonylation reaction, and the reaction conditions were: 215℃, 1.5MPa, GHSV=4800ml·g -1 ·h -1 , DME / CO / N2=1 / 19 / 5, performance test results see Figure 3 , Figure 4 It can be found from the figure that when the ratio is in the range of 3:20-3:8, the modified catalysts have good stability and the selectivity is close to 100% without decreasing. When the ratio increases to 3:2, the conversion rate can reach up to 87.4%.

[0059] Experimental Example 2

[0060] The preparation method of Cu-Pya-HMOR15-550 (3:13) sample is shown in Example 1. Take 2g HMOR15, add it to 30ml 0.2mol / L Cu(NO3)2 solution, ion exchange for 3h in 80℃ water bath with stirring, filter, wash 3 times, dry in oven at 110℃ overnight, calcine at 450℃ for 3h to obtain Cu-HMOR15 sample. Take 2g of the above Cu-HMOR15 sample, add it to 20ml 1.3mol / L Pya·H3PO4 solution, ion exchange for 3h in 80℃ water bath with stirring, filter, wash 3 times, dry in oven at 110℃ overnight, press into tablets and granulate, the sample is recorded as Cu-Pya-HMOR15-450 (1:4). The above process was repeated, but the calcination temperature was changed to 350°C, and the obtained sample was recorded as Cu-Pya-HMOR15-350 (3:13). 0.25g of 40-60 mesh Cu-Pya-HMOR15-550 (3:13), Cu-Pya-HMOR15-450 (1:4), and Cu-Pya-HMOR15-350 (3:13) were respectively taken in a fixed bed reactor for DME carbonylation reaction, and the reaction conditions were: 215°C, 1.5MPa, GHSV = 4800ml·g -1 ·h -1 , DME / CO / N2=1 / 19 / 5, performance test results see Figure 5 , Figure 6 .

[0061] Example 3

[0062] A Cu-Pya-HMOR15-550 (3:20) sample was prepared as described in Example 1. 0.25 g of 40-60 mesh Cu-Pya-HMOR15-550 (3:20) sample was taken and subjected to DME carbonylation reaction in a fixed bed reactor. The reaction temperatures were 185°C, 200°C, 215°C, and 230°C, respectively. The other conditions were the same as those in Example 1. The performance test results are shown in FIG. Figure 7 , Figure 8 .

[0063] Example 4

[0064] A Cu-Pya-HMOR15-550 (3:13) sample was prepared as described in Example 1. 0.25 g of a 40-60 mesh Cu-Pya-HMOR15-550 (1:4) sample was used for DME carbonylation reaction. The reaction space velocities were 3600 ml·g -1 ·h -1 、4800ml·g -1 ·h -1 、6000ml·g -1 ·h-1 The other conditions are the same as those in Example 1. The performance test results are shown in Fig. 9 , Fig.10 .

[0065] Example 5

[0066] Take 2g HMOR15, add it to 30ml Cu(NO3)2 solution with a concentration of 0.33mol / L, ion exchange for 3h in 80℃ water bath with stirring, filter, wash 3 times, dry in oven at 110℃ overnight, calcine at 550℃ for 3h, take the above prepared sample and add it to 20ml 1.3mol / L Pya·H3PO4 solution, ion exchange for 3h in 80℃ water bath with stirring, filter, wash 3 times, dry in oven at 110℃ overnight, press into tablets, and record the sample as Cu-Pya-HMOR15-80℃. Repeat the above process, but change the ion exchange temperature to 25℃ twice, and record the sample as Cu-Pya-HMOR15-25℃. 0.25 g of 40-60 mesh Cu-Pya-HMOR15-25°C and Cu-Pya-HMOR15-80°C samples were respectively taken in a fixed bed reactor for DME carbonylation reaction. The reaction conditions were the same as in Example 1. The performance test results are shown in Fig.11 , Fig.12 .

[0067] Example 6

[0068] Take 2g HMOR15, add it to 30ml Cu(NO3)2 solution with a concentration of 0.33mol / L, ion exchange for 3h in 80℃ water bath with stirring, filter, wash 3 times, dry in oven at 110℃ overnight, calcine at 550℃ for 3h, take the above prepared sample and add it to 20ml 1.3mol / L Pya·H3PO4 solution, ion exchange for 3h in 80℃ water bath with stirring, filter, wash 3 times, dry in oven at 110℃ overnight, press into tablets, and record the sample as Cu-Pya-HMOR15-3h. Repeat the above process, but change the ion exchange time to 1h twice, and record the sample as Cu-Pya-HMOR15-1h. 0.25 g of 40-60 mesh Cu-Pya-HMOR15-1h and Cu-Pya-HMOR15-3h were respectively taken in a fixed bed reactor for DME carbonylation reaction. The reaction conditions were the same as in Example 1. The performance test results are shown in Fig.13 , Fig.14 .

[0069] Example 7

[0070] A Cu-Pya-HMOR15-550 (3:13) sample was prepared as described in Example 1. 0.25 g of a 40-60 mesh Cu-Pya-HMOR15-550 (3:20) sample was taken and subjected to DME carbonylation reaction in a fixed bed reactor. The reaction conditions were the same as those in Example 1. A stability test was performed for 100 h. The test results are shown in Fig.15 The results showed that the catalyst could react for 80 hours without deactivation, and after 80 hours of reaction, it began to show a slow downward trend.

[0071] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for preparing a hydrogen-type mordenite catalyst modified by copper and pyrazole phosphate, characterized in that The following steps are involved: (1) adding powdered hydrogen-type mordenite to a copper salt aqueous solution, stirring to carry out ion exchange, and then filtering, washing, drying and calcining to obtain a copper-modified hydrogen-type mordenite catalyst; (2) adding the copper-modified hydrogen-type mordenite catalyst to the pyrazole phosphate solution, stirring for ion exchange, and then filtering, washing, and drying to obtain a copper-pyrazole phosphate-modified hydrogen-type mordenite catalyst; The ion exchange temperature in step (1) is 25-80 ℃, and the ion exchange time is 1-3h; The calcination temperature in step (1) is 350-550 ℃; Step (2) in which the pyrazole phosphate solution is obtained by the reaction of phosphoric acid and pyrazole, wherein the pyrazole phosphate is Pya·H3PO4; In the steps (1) and (2) of the copper and pyrazole phosphate modified hydrogen-type mordenite catalyst preparation process, the molar ratio of the copper salt and the pyrazole phosphate for ion exchange is 3:20-3:2; The temperature of the ion exchange in step (2) is 25-80° C., and the time of the ion exchange is 1-3 h.

2. The method for preparing the copper and pyrazole phosphate modified hydrogen-type mordenite catalyst according to claim 1, characterized in that: The copper salt in step (1) is at least one of copper nitrate, copper chloride and copper acetate; The concentration of the copper salt aqueous solution in step (1) is 5.2-0.013 mol / L.

3. A hydrogen-type mordenite catalyst modified with copper and pyrazole phosphate prepared according to the method according to any one of claims 1 to 2.

4. The use of the copper and pyrazole phosphate modified hydrogen-type mordenite catalyst in carbonylation of dimethyl ether to produce methyl acetate according to claim 3, characterized in that Dimethyl ether and CO are used as reaction gases, the molar ratio of dimethyl ether to CO is 1:10-50; Ar gas or N2 gas is used as diluent gas, and the dilution gas volume fraction is 0-50%; the reaction temperature is 185-230℃; the reaction pressure is 1-5MPa, and the reaction space velocity is 2000-20000ml·g -1 ·h -1 .

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