A cobalt-nickel / attapulgite-based mordenite catalyst, its preparation method and application

Abstract

The application discloses a cobalt-nickel / attapulgite-based mordenite catalyst and a preparation method and application thereof, and comprises a carrier and an active component loaded on the carrier, the carrier is an attapulgite-based mordenite, the active component is cobalt and nickel, and the attapulgite-based mordenite is prepared by a hydrothermal method with attapulgite as raw material. The catalyst is applied to catalytic depolymerization of lignin to prepare guaiacol, and in a water, glycerol and formic acid system and a nitrogen atmosphere, 100% lignin conversion rate can be realized, the guaiacol yield is greater than 30%, and the guaiacol product yield is greater than 80%. The catalyst has the advantages of high economic benefit and product concentration, can improve the depolymerization capacity and selectivity of the catalyst to lignin, and has a good industrial application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lignin depolymerization, and particularly relates to a cobalt-nickel / attapulgite-based mordenite catalyst and a preparation method and application thereof. BACKGROUND

[0002] Biomass is the main sustainable organic carbon source in nature, which provides great potential for addressing environmental challenges and promoting the realization of a carbon-neutral society. Lignin is an important component of lignocellulosic biomass, so it is imperative to rationally develop and utilize lignin. In recent years, converting lignin into value-added products such as bio-oil and phenolic compounds through liquefaction, pyrolysis and other thermochemical methods has become a very promising technology.

[0003] It is reported that cobalt-based catalysts can achieve selective cleavage of ether bonds in lignin, and due to their low cost and stable performance, they are commonly used for lignin depolymerization. However, cobalt-based catalysts have low adsorption energy for active hydrogen, and usually require high temperature and pressure (temperature greater than 350 DEG C, pressure greater than 10 MPa during the reaction process), in addition, the macromolecular fragments produced by lignin cracking are highly reactive and easily re-polymerized into polymers, resulting in low expected yield or selectivity of target products. Therefore, improving the intrinsic activity and selectivity of cobalt-based catalysts is a challenge for current research. SUMMARY

[0004] The main purpose of the present application is to provide a cobalt-nickel / attapulgite-based mordenite catalyst which can catalyze lignin depolymerization to prepare guaiacol, and has low reaction condition requirements and high selectivity of target products, and a preparation method and application thereof.

[0005] To achieve the above-mentioned purpose, the present application provides a cobalt-nickel / attapulgite-based mordenite catalyst, which comprises a carrier and an active component loaded on the carrier, the carrier is attapulgite-based mordenite, and the active component is cobalt and nickel, and the attapulgite-based mordenite is prepared by hydrothermal method using attapulgite as raw material.

[0006] Further, the content of nickel is 5-15wt%, the content of cobalt is 5-15wt%, and the balance is attapulgite-based mordenite.

[0007] The present application also provides a preparation method of the above-mentioned cobalt-nickel / attapulgite-based mordenite catalyst, which comprises the following steps:

[0008] (1) mixing acid-treated attapulgite with tetraethylammonium bromide, sodium hydroxide, sodium aluminate and water, and then performing hydrothermal crystallization treatment, and then sequentially performing washing, drying and calcination treatment on the obtained product to obtain sodium-type attapulgite-based mordenite;

[0009] (2) adding the sodium-type attapulgite-based mordenite into a sodium chloride aqueous solution to perform ion exchange treatment, to obtain the attapulgite-based mordenite;

[0010] (3) loading cobalt and nickel on the attapulgite-based mordenite to obtain the cobalt-nickel / attapulgite-based mordenite catalyst.

[0011] Further, in step (1), the mass ratio of the attapulgite after acid treatment, tetraethylammonium bromide, sodium hydroxide, sodium aluminate and water is 1:0.08:0.42:0.1-0.5:40, the temperature of hydrothermal crystallization treatment is 160-220℃, and the time is 92-200h.

[0012] Further, in step (1), the temperature of drying treatment is 50-80℃, and the time is 12-24h; the calcination treatment is performed in an air atmosphere, and the specific process is to raise the temperature to 450-600℃ at a temperature raising rate of 1-5℃ / min, and then to calcine for 4-10h.

[0013] Further, in step (2), the concentration of the sodium chloride aqueous solution is 1-5mol / L, the temperature of ion exchange treatment is 90℃, the time is 4h, and the number of ion exchange treatment is three times.

[0014] Further, the specific process of step (3) is as follows: the attapulgite-based mordenite is added into a cobalt precursor salt solution, stirred at room temperature for 12-24h, then the solvent is evaporated, then dried at a temperature of 50-80℃ for 12-24h, and finally calcined in an air atmosphere at a temperature raising rate of 1-5℃ / min to 450-600℃ for 4-10h, to obtain the cobalt / attapulgite-based mordenite;

[0015] The cobalt / attapulgite-based mordenite is added into a nickel precursor salt solution, stirred at room temperature for 12-24h, then the solvent is evaporated, then dried at a temperature of 50-80℃ for 12-24h, and finally calcined in an air atmosphere at a temperature raising rate of 1-5℃ / min to 450-600℃ for 4-10h, to obtain the cobalt-nickel / attapulgite-based mordenite catalyst.

[0016] The application also provides application of the above-mentioned catalyst in catalyzing lignin depolymerization to prepare guaiacol under the condition that water, glycerol and formic acid are used as reaction solvents and no external hydrogen source is provided.

[0017] The application also provides a method for catalyzing lignin depolymerization to prepare guaiacol, which comprises the following steps: mixing glycerol, deionized water and formic acid at a volume ratio of 1:1-10:0.1 to obtain a reaction solvent, and putting the reaction solvent, lignin and the catalyst as claimed in claim 1 or 2 into a reaction kettle to perform reaction.

[0018] Further, the volume mass ratio of the reaction solvent, the lignin and the catalyst is 11.1-55.5 ml:1 g:0.1-0.5 g, and the reaction conditions are temperature 270-350 ℃, stirring speed 400-800 r / min, and reaction time 6-12 h.

[0019] The catalyst of the present application adopts attapulgite-based mordenite as a carrier, and the mordenite synthesized by using attapulgite as a raw material has an optimized pore size, and the produced mesoporous structure is beneficial to the depolymerization of lignin. Meanwhile, the eight-membered ring and twelve-membered ring structures in the mordenite provide abundant B acid sites, which play a key role in adsorbing and activating the C-C bonds and C-O bonds in lignin.

[0020] The cobalt-nickel mixture as an active component can enhance the ability of the catalyst to activate the hydrogen in the hydrogen-donating solvent into active hydrogen ions; the addition of the metal nickel makes the cobalt disperse, so that the cobalt is more uniformly dispersed on the carrier, which is attributed to the interaction between the metals. Meanwhile, the cobalt and the aluminum in the carrier change in structure to form a Co-O-Al bond, and the existence of the metal interaction between the nickel and the cobalt leads to the generation of oxygen defects, and the oxygen defects can enhance the adsorption polarization of the ether bonds in lignin by the catalyst, thereby promoting the depolymerization of lignin.

[0021] The beneficial effects of the present application are embodied in that:

[0022] The catalyst of the present application is applied to catalytic depolymerization of lignin to prepare guaiacol, and in a water, glycerol and formic acid system and a nitrogen atmosphere, the lignin conversion rate can reach 100%, the guaiacol yield is greater than 30%, and the guaiacol product yield is greater than 80%; the catalyst has high economic benefits and the advantage of product concentration, can improve the depolymerization ability and selectivity of the catalyst to lignin, and has a good industrial application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The XRD spectrum of the attapulgite-based mordenite prepared in Example 1.

[0024] Figure 2 The SEM image of the attapulgite-based mordenite prepared in Example 1.

[0025] Figure 3 The infrared spectrum of the attapulgite-based mordenite prepared in Example 1.

[0026] Figure 4 The XRD spectrum of the final product of step (2) in Comparative Example 1.

[0027] Figure 5 The N2 adsorption-desorption isotherm graph of the attapulgite-based mordenite prepared in Example 1.

[0028] Figure 6 The pore size distribution of the attapulgite-based ZSM-5 zeolite prepared in Example 1 is shown in the following figure. DETAILED DESCRIPTION

[0029] In order to make the skilled in the art more clearly understand the technical solutions described in the present application, the following examples are listed for illustration. It should be pointed out that the following examples do not constitute a limitation on the scope of protection required by the present application.

[0030] Unless otherwise specified, the raw materials used in the examples of the present application are commercially available or can be obtained by those skilled in the art; unless otherwise specified, the methods used in the examples of the present application are methods mastered by those skilled in the art.

[0031] Example 1

[0032] Preparation of cobalt-nickel / attapulgite-based ZSM-5 zeolite catalyst

[0033] The catalyst prepared in this example has a cobalt content of 5wt%, a nickel content of 10wt%, and the remaining component is the carrier attapulgite-based ZSM-5 zeolite, and the preparation method is as follows:

[0034] (1) 20g of attapulgite was weighed and placed in a 120mL 6mol / L hydrochloric acid solution, stirred at a temperature of 60℃ and a stirring speed of 350r / min for 12h, then placed in a polytetrafluoroethylene liner for hydrothermal treatment at 170℃ for 12h, then filtered and washed, dried at 120℃ for 12h, to obtain the acid-treated attapulgite; 6g of the acid-treated attapulgite was mixed with tetraethylammonium bromide, sodium hydroxide, sodium aluminate and water in a mass ratio of 1:0.08:0.42:0.1:40, then hydrothermally crystallized at 180℃ for 96h, then centrifuged to obtain the product, washed with deionized water, and then dried at 80℃ for 12h, finally heated to 550℃ at a heating rate of 5℃ / min in an air atmosphere and held at this temperature for 6h to obtain sodium-type attapulgite-based ZSM-5 zeolite.

[0035] (2) The sodium-type attapulgite-based ZSM-5 zeolite was added to a 2mol / L sodium chloride aqueous solution and ion exchanged at 90℃ for 4h, and the above operation was repeated three times to obtain the attapulgite-based ZSM-5 zeolite.

[0036] (3) 1g of the attapulgite-based ZSM-5 zeolite and 0.2743g of cobalt nitrate hexahydrate were placed in 200mL of deionized water, stirred at room temperature at a stirring speed of 350r / min for 12h, then evaporated the water at 90℃, then dried at 80℃ for 12h, and finally heated to 550℃ at a heating rate of 4℃ / min in an air atmosphere and held at this temperature for 4h to obtain cobalt / attapulgite-based ZSM-5 zeolite.

[0037] (4) Take 1 g of cobalt / attapulgite-based ZSM-5 zeolite, 0.2752 g of nickel nitrate hexahydrate, and place them in 200 mL of deionized water. Stir at a stirring rate of 350 r / min at room temperature for 12 h. Then evaporate the water at 90 °C. After that, dry at 80 °C for 12 h. Finally, heat to 600 °C at a heating rate of 4 °C / min in air atmosphere and keep the temperature constant for 6 h to obtain a cobalt-nickel / attapulgite-based ZSM-5 zeolite catalyst, numbered C1.

[0038] Example 2

[0039] Preparation of cobalt-nickel / attapulgite-based ZSM-5 zeolite catalyst

[0040] The catalyst prepared in this example has a cobalt content of 5 wt%, a nickel content of 5 wt%, and the remaining component is the carrier attapulgite-based ZSM-5 zeolite. The preparation method is as follows:

[0041] (1) Take 6 g of acid-treated (the treatment process is the same as in Example 1) attapulgite, and mix it with tetraethylammonium bromide, sodium hydroxide, sodium aluminate, and water according to a mass ratio of 1:0.08:0.42:0.2:40. Then hydrothermally crystallize at 160 °C for 200 h. After that, centrifuge the product, wash it with deionized water, and then dry at 70 °C for 15 h. Finally, heat to 600 °C at a heating rate of 4 °C / min in air atmosphere and keep the temperature constant for 4 h to obtain sodium-type attapulgite-based ZSM-5 zeolite.

[0042] (2) Add the sodium-type attapulgite-based ZSM-5 zeolite to a 3 mol / L aqueous sodium chloride solution and ion exchange at 90 °C for 4 h. Repeat the above operation three times to obtain attapulgite-based ZSM-5 zeolite.

[0043] (3) Take 1 g of attapulgite-based ZSM-5 zeolite and 0.2424 g of cobalt acetylacetonate, and dissolve them in 200 mL of anhydrous ethanol. Stir at a stirring rate of 350 r / min at room temperature for 14 h. Then evaporate the ethanol at 75 °C. After that, dry at 70 °C for 16 h. Finally, heat to 450 °C at a heating rate of 5 °C / min in air atmosphere and keep the temperature constant for 10 h to obtain cobalt / attapulgite-based ZSM-5 zeolite.

[0044] (4) Take 1 g of cobalt / attapulgite-based ZSM-5 zeolite and 0.2432 g of nickel acetylacetonate, and place them in 200 mL of anhydrous ethanol. Stir at a stirring rate of 350 r / min at room temperature for 14 h. Then evaporate the ethanol at 75 °C. After that, dry at 70 °C for 16 h. Finally, heat to 500 °C at a heating rate of 5 °C / min in air atmosphere and keep the temperature constant for 8 h to obtain a cobalt-nickel / attapulgite-based ZSM-5 zeolite catalyst, numbered C2.

[0045] Example 3

[0046] Preparation of cobalt-nickel / attapulgite-based ZSM-5 zeolite catalyst

[0047] The catalyst prepared in this example has a cobalt content of 10 wt%, a nickel content of 5 wt%, and the remaining component is the support attapulgite-based mordenite. The preparation method is as follows:

[0048] (1) 6 g of the acid-treated (the treatment process is the same as in Example 1) attapulgite was mixed with tetraethylammonium bromide, sodium hydroxide, sodium aluminate, and water in a mass ratio of 1:0.08:0.42:0.3:40, and then hydrothermally crystallized at 220°C for 92 h. After that, the product was centrifuged, washed with deionized water, and then dried at 60°C for 18 h. Finally, it was heated to 500°C at a heating rate of 3°C / min in an air atmosphere and calcined at a constant temperature for 8 h to obtain sodium-type attapulgite-based mordenite.

[0049] (2) The sodium-type attapulgite-based mordenite was added to a 1 mol / L sodium chloride aqueous solution and ion exchanged at 90°C for 4 h. The above operation was repeated three times to obtain attapulgite-based mordenite.

[0050] (3) 1 g of attapulgite-based mordenite and 0.4486 g of cobalt chloride hexahydrate were placed in 200 mL of deionized water, stirred at a stirring rate of 350 r / min at room temperature for 16 h, and then evaporated to dryness at 95°C. After that, it was dried at 60°C for 20 h, and finally heated to 500°C at a heating rate of 3°C / min in an air atmosphere and calcined at a constant temperature for 8 h to obtain cobalt / attapulgite-based mordenite.

[0051] (4) 1 g of cobalt / attapulgite-based mordenite and 0.2449 g of nickel chloride hexahydrate were placed in 200 mL of anhydrous ethanol, stirred at a stirring rate of 350 r / min at room temperature for 16 h, and then evaporated to dryness at 95°C. After that, it was dried at 60°C for 20 h, and finally heated to 550°C at a heating rate of 3°C / min in an air atmosphere and calcined at a constant temperature for 6 h to obtain a cobalt-nickel / attapulgite-based mordenite catalyst, numbered C3.

[0052] Example 4

[0053] Preparation of a cobalt-nickel / attapulgite-based mordenite catalyst

[0054] The catalyst prepared in this example has a cobalt content of 10 wt%, a nickel content of 10 wt%, and the remaining component is the support attapulgite-based mordenite. The preparation method is as follows:

[0055] (1) 6 g of the acid-treated (treatment process same as Example 1) attapulgite was mixed with tetraethylammonium bromide, sodium hydroxide, sodium aluminate and water in a mass ratio of 1:0.08:0.42:0.4:40, and then hydrothermally crystallized at 170°C for 150 h. The product was centrifuged, washed with deionized water, and dried at 50°C for 24 h. Finally, it was heated to 450°C at a rate of 2°C / min in air atmosphere and calcined at 450°C for 10 h to obtain sodium-type attapulgite-based mordenite.

[0056] (2) The sodium-type attapulgite-based mordenite was ion-exchanged in 4 mol / L aqueous sodium chloride solution at 90°C for 4 h, and the above operation was repeated three times to obtain attapulgite-based mordenite.

[0057] (3) 1 g of attapulgite-based mordenite and 0.5962 g of cobalt sulfate heptahydrate were placed in 200 mL of deionized water, stirred at a stirring rate of 350 r / min at room temperature for 18 h, and then evaporated to dryness at 90°C. After drying at 60°C for 16 h, it was heated to 600°C at a rate of 2°C / min in air atmosphere and calcined at 600°C for 4 h to obtain cobalt / attapulgite-based mordenite.

[0058] (4) 1 g of cobalt / attapulgite-based mordenite and 0.5982 g of nickel sulfate heptahydrate were placed in 200 mL of deionized water, stirred at a stirring rate of 350 r / min at room temperature for 18 h, and then evaporated to dryness at 90°C. After drying at 60°C for 16 h, it was heated to 600°C at a rate of 2°C / min in air atmosphere and calcined at 600°C for 4 h to obtain cobalt-nickel / attapulgite-based mordenite catalyst, No. C4.

[0059] Example 5

[0060] Preparation of cobalt-nickel / attapulgite-based mordenite catalyst

[0061] The catalyst prepared in this example has a cobalt content of 15 wt%, a nickel content of 15 wt%, and the remaining component is the carrier attapulgite-based mordenite. The preparation method is as follows:

[0062] (1) 6 g of the acid-treated (treatment process same as Example 1) attapulgite was mixed with tetraethylammonium bromide, sodium hydroxide, sodium aluminate and water in a mass ratio of 1:0.08:0.42:0.5:40, and then hydrothermally crystallized at 200°C for 110 h. The product was centrifuged, washed with deionized water, and dried at 60°C for 20 h. Finally, it was heated to 550°C at a rate of 1°C / min in air atmosphere and calcined at 550°C for 6 h to obtain sodium-type attapulgite-based mordenite.

[0063] (2) Sodium-type palygorskite-based mordenite was ion exchanged in 5 mol / L aqueous sodium chloride solution at 90°C for 4 h, and the above operation was repeated three times to obtain palygorskite-based mordenite.

[0064] (3) 1 g of palygorskite-based mordenite and 1.333 g of cobalt phosphate octahydrate were placed in 100 mL of methanol, stirred at a stirring rate of 350 r / min at room temperature for 20 h, and then methanol was evaporated at 60°C. After that, the mixture was dried at 50°C for 24 h, and finally, the temperature was raised to 500°C at a temperature raising rate of 1°C / min in air atmosphere and then the mixture was calcined at 500°C for 6 h to obtain cobalt / palygorskite-based mordenite.

[0065] (4) 1 g of cobalt / palygorskite-based mordenite and 1.331 g of nickel phosphate octahydrate were dissolved in 100 mL of methanol, stirred at a stirring rate of 350 r / min at room temperature for 20 h, and then methanol was evaporated at 60°C. After that, the mixture was dried at 50°C for 24 h, and finally, the temperature was raised to 450°C at a temperature raising rate of 1°C / min in air atmosphere and then the mixture was calcined at 450°C for 10 h to obtain cobalt-nickel / palygorskite-based mordenite catalyst, numbered C5.

[0066] Comparative Example 1

[0067] Preparation of Comparative Catalyst

[0068] The preparation process of the present comparative example was the same as that of Example 1, except that the crystallization temperature in step (1) was adjusted to 150°C, and the prepared catalyst was numbered D1.

[0069] Comparative Example 2

[0070] Preparation of Comparative Catalyst

[0071] The preparation process of the present comparative example was the same as that of Example 1, except that the crystallization temperature in step (1) was adjusted to 230°C, and the prepared catalyst was numbered D2.

[0072] Comparative Example 3

[0073] Preparation of Comparative Catalyst

[0074] The preparation process of the present comparative example was the same as that of Example 1, except that the amount of sodium hydroxide in step (1) was adjusted to 0.45 times the mass of palygorskite, and the prepared catalyst was numbered D3.

[0075] Comparative Example 4

[0076] Preparation of Comparative Catalyst

[0077] The preparation process of the present comparative example was the same as that of Example 1, except that the calcination temperature in step (1) was adjusted to 610°C, and the prepared catalyst was numbered D4.

[0078] Comparative Example 5

[0079] Preparation of comparative catalysts

[0080] The preparation process of this comparative example is the same as that of Example 1, except that step (4) is omitted and the amount of cobalt nitrate hexahydrate in step (3) is adjusted to 0.2599 g, resulting in a catalyst having a cobalt content of 5 wt % and the remaining component being a carrier attapulgite-based mordenite, numbered D5.

[0081] Comparative Example 6

[0082] Preparation of comparative catalysts

[0083] The preparation process of this comparative example is the same as that of Example 1, except that the nickel nitrate hexahydrate in step (4) is replaced by 0.8029 g of zinc nitrate hexahydrate, to obtain a catalyst having a cobalt content of 5 wt% and a zinc content of 10 wt%, with the remaining component being a carrier attapulgite-based mordenite, numbered D6.

[0084] Comparative Example 7

[0085] Preparation of comparative catalysts

[0086] The preparation process of this comparative example is the same as that of Example 1, except that the carrier in step (3) is replaced by acid-treated attapulgite, and the obtained catalyst is numbered D7.

[0087] Experimental Example 1

[0088] Structural determination of the vector

[0089] The attapulgite-based mordenite prepared in Example 1 was subjected to XRD, SEM and infrared spectroscopy analysis, and the results were as follows:

[0090] See also Figure 1 , in the XRD spectrum of attapulgite-based mordenite Figure 2 Characteristic diffraction peaks corresponding to the structure of mordenite were detected at θ=6.5°, 9.8°, 13.5°, 19.7°, 22.4°, 23.3°, 25.8°, 25.7°, 26.4°, 27.7°, 31.1° and 35.9°, proving that the mordenite material was successfully prepared using attapulgite as the silicon source.

[0091] See also Figure 2 From the SEM image of attapulgite-based mordenite, the unique rod-like structure of attapulgite-based mordenite can be observed.

[0092] See also Figure 3 , at 450cm -1 The band at 600 cm-1 can be attributed to the stretching vibration of TO (T = Si / Al) in mordenite; -1The vibration peaks of the region are due to the stretching vibration of the pentasil rings in the mordenite; the vibration peaks at 780 cm -1 are due to the tetrahedral in-plane and out-of-plane symmetric stretching vibration of the mordenite; the vibration peaks near 1080 cm -1 are due to the tetrahedral in-plane and out-of-plane asymmetric stretching vibration of the mordenite. The pentasil rings are parallel to each other in pairs, i.e. two pentasil rings share two tetrahedrons. The paired pentasil rings can be further linked to another paired pentasil rings through oxygen bridges, and a four-membered ring is formed at the linking position. If further rings are linked to each other, an eight-membered ring and a twelve-membered ring can be formed.

[0093] The final product prepared in Step (2) of the Comparative Example 1 was subjected to XRD analysis, and the results are shown in Figure 4 . The XRD pattern showed that the diffraction peaks were not consistent with those of the mordenite, indicating that the mordenite structure was not successfully crystallized under the condition of hydrothermal crystallization at a temperature of 150°C. In addition, the final product prepared in Step (2) of the Comparative Example 2 was also subjected to XRD analysis, and it was found that the mordenite structure was not successfully crystallized. However, the mordenite structure was detected in the Comparative Examples 3 and 4. The inventors found through a large number of experiments that the crystallization temperature is the most important factor affecting the formation of the mordenite structure. The mordenite structure can be obtained within a crystallization time of 92-200 h when the crystallization temperature is in the range of 160-220°C, and the mordenite structure cannot be obtained regardless of the time when the temperature is out of the range. For the sake of brevity, the XRD patterns of the Comparative Examples are not described in detail.

[0094] The pore size and specific surface area of the attapulgite-based mordenite prepared in the Examples 1-5, the Comparative Example 3 and the Comparative Example 4 were determined, and the results are shown in Table 1. The N2 adsorption-desorption isotherm graph of the attapulgite-based mordenite of Example 1 is shown in Figure 5 , and the pore size distribution graph is shown in Figure 6 . For the sake of brevity, the N2 adsorption-desorption isotherm graphs and the pore size distribution graphs of the other examples and comparative examples are not described in detail.

[0095] Table 1

[0096]

[0097] It can be seen that the attapulgite-based mordenite prepared in the present application has a mesoporous structure, and the pore size and specific surface area of the Comparative Examples 3 and 4 cannot reach the effect of the present application after adjusting the amount of sodium hydroxide and the calcination temperature.

[0098] Experimental Example 2

[0099] Performance test of the catalyst for catalytic hydrogenation depolymerization of lignin to prepare guaiacol

[0100] Experimental method: 1g of lignin, 0.1-0.5g of catalyst, 1-5ml of glycerol, 10-50ml of deionized water and 0.1-0.5ml of formic acid were added into a high-pressure reaction kettle, 0.1-0.5MPa initial nitrogen pressure was filled, then heated to 270-350℃ within 30min with a stirring speed of 450r / min for sealed reaction of 6-12h. After the reaction was completed, ice water was used for cooling, then impurities were removed by suction filtration, then the remaining liquid phase product was extracted by ethyl acetate, then the ethyl acetate layer was taken out, then unseparated water was removed by a chromatographic column containing anhydrous sodium sulfate, finally ethyl acetate was removed by rotary evaporation under the conditions of a temperature of 55℃ and a rotating speed of 65r / min, then the rotary evaporation product was subjected to quantitative analysis. The specific reaction conditions and results are shown in Table 2.

[0101] Table 2

[0102]

[0103]

[0104] The above merely describes the preferred embodiments of the present application and is not used to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A cobalt-nickel / attapulgite-based mordenite catalyst for catalyzing the depolymerization of lignin to prepare guaiacol, characterized in that: The invention comprises a carrier and an active component loaded on the carrier, wherein the carrier is attapulgite-based mordenite, the active components are cobalt and nickel, the attapulgite-based mordenite is prepared by a hydrothermal method using attapulgite as a raw material, and the preparation method of the attapulgite-based mordenite comprises the following steps: (1) mixing the acid-treated attapulgite with tetraethylammonium bromide, sodium hydroxide, sodium aluminate, and water, and then subjecting the mixture to hydrothermal crystallization. The resulting product is sequentially washed, dried, and calcined to obtain sodium-type attapulgite-based mordenite; (2) Sodium-type attapulgite-based mordenite is added to a sodium chloride aqueous solution for ion exchange treatment to obtain attapulgite-based mordenite.

2. The cobalt-nickel / attapulgite-based mordenite catalyst according to claim 1, characterized in that The nickel content is 5-15wt%, the cobalt content is 5-15wt%, and the balance is attapulgite-based mordenite.

3. The cobalt-nickel / attapulgite-based mordenite catalyst according to claim 1 or 2, characterized in that In step (1), the mass ratio of the acid-treated attapulgite to tetraethylammonium bromide, sodium hydroxide, sodium aluminate, and water is 1:0.08:0.42:0.1-0.5:40, and the temperature of the hydrothermal crystallization treatment is 160-220° C., and the time is 92-200 h.

4. The cobalt-nickel / attapulgite-based mordenite catalyst according to claim 1 or 2, characterized in that In step (1), the drying temperature is 50-80°C and the drying time is 12-24 hours; the calcination is carried out in an air atmosphere, and the specific process is to heat the temperature to 450-600°C at a heating rate of 1-5°C / min and calcine for 4-10 hours.

5. The cobalt-nickel / attapulgite-based mordenite catalyst according to claim 1 or 2, characterized in that In step (2), the concentration of the sodium chloride aqueous solution is 1 to 5 mol / L, the temperature of the ion exchange treatment is 90° C., the time is 4 h, and the number of ion exchange treatments is three times.

6. The method for preparing the cobalt-nickel / attapulgite-based mordenite catalyst according to any one of claims 1 to 5, characterized in that: The following steps are involved: Cobalt and nickel are loaded on attapulgite-based mordenite to obtain the cobalt-nickel / attapulgite-based mordenite catalyst.

7. The method for preparing the cobalt-nickel / attapulgite-based mordenite catalyst according to claim 6, wherein: The specific process is as follows: adding attapulgite-based mordenite to a cobalt precursor salt solution, stirring at room temperature for 12 to 24 hours, evaporating the solvent, then drying at 50 to 80°C for 12 to 24 hours, and finally calcining at 450 to 600°C in an air atmosphere at a heating rate of 1 to 5°C / min for 4 to 10 hours to obtain cobalt / attapulgite-based mordenite; The cobalt / attapulgite-based mordenite is added to a nickel precursor salt solution, stirred at room temperature for 12 to 24 hours, and then the solvent is evaporated. The solution is then dried at 50 to 80° C. for 12 to 24 hours, and finally calcined at 450 to 600° C. in an air atmosphere at a heating rate of 1 to 5° C. / min for 4 to 10 hours to obtain the cobalt-nickel / attapulgite-based mordenite catalyst.

8. Use of the catalyst according to any one of claims 1 to 5 in catalyzing the depolymerization of lignin to prepare guaiacol using water, glycerol and formic acid as reaction solvents and without an external hydrogen source.

9. A method for preparing guaiacol by catalytic depolymerization of lignin, characterized in that: The following steps are involved: Glycerol, deionized water and formic acid are mixed in a volume ratio of 1:1 to 10:0.1 to obtain a reaction solvent. The reaction solvent, lignin and the catalyst according to any one of claims 1 to 5 are added into a reactor to react.

10. The method for preparing guaiacol by catalyzing the depolymerization of lignin according to claim 9, characterized in that: The volume mass ratio of the reaction solvent, lignin and catalyst is 11.1-55.5 ml: 1 g: 0.1-0.5 g, and the reaction conditions are temperature 270-350° C., stirring speed 400-800 r / min and reaction time 6-12 h.

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