Alkali-modified usy molecular sieves, methods of making and using the same, and methods of making 2,6-diisopropyl naphthalene

Abstract

This invention provides an alkali-modified USY molecular sieve, its preparation method and application, and a method for preparing 2,6-diisopropylnaphthalene. The preparation method of the alkali-modified USY molecular sieve includes: preparing a mixed alkaline solution comprising an inorganic base and a quaternary ammonium base; immersing the USY molecular sieve in the mixed alkaline solution for alkali treatment; filtering; washing; drying; and calcining to obtain the alkali-modified USY molecular sieve. This invention uses a mixed alkaline solution comprising an inorganic base and a quaternary ammonium base to treat USY molecular sieve to prepare alkali-modified USY molecular sieve. When applied to the reaction of naphthalene and / or 2-isopropylnaphthalene with propylene to prepare 2,6-diisopropylnaphthalene, it has the advantages of high naphthalene source conversion and high selectivity for 2,6-diisopropylnaphthalene. Furthermore, the catalyst has good reusability and can be reused multiple times.

Description

Technical Field

[0001] This invention belongs to the field of molecular sieve catalyst technology, specifically relating to an alkali-modified USY molecular sieve and its preparation method and application, and a method for preparing 2,6-diisopropylnaphthalene. Background Technology

[0002] 2,6-Diisopropylnaphthalene (2,6-DIPN) is an important organic chemical raw material with advantages such as being colorless, odorless, having a high boiling point, low toxicity, low freezing point, and strong fuel solubility. 2,6-Diisopropylnaphthalene (2,6-DIPN) can be used to synthesize 2,6-naphthalenedicarboxylic acid, which can be used in the production of polyethylene terephthalate (PEN) and thermally oriented liquid crystal polymers (LCPs), making it a high-value-added fine chemical product. PEN possesses unique heat resistance, mechanical properties, gas barrier properties, chemical stability, and radiation resistance, and is widely used in electronic devices, high-performance films, food packaging films, insulating materials, and aerospace. Currently, the bottleneck for the large-scale application of PEN lies in the cumbersome preparation process and high production cost of its key raw material, 2,6-diisopropylnaphthalene.

[0003] The synthesis of diisopropylnaphthalene generally employs a liquid-phase alkylation method with naphthalene and propylene / isopropanol. Due to the numerous isomers of 2,6-diisopropylnaphthalene with similar boiling points, separation is extremely difficult. Furthermore, current techniques generally exhibit low selectivity for 2,6-diisopropylnaphthalene in the diisopropylnaphthalene product, and the reusability of catalysts is not ideal. For example, Chu et al. (Applied Catalysis A: General 123 (1995) 51-58) found that using ultrastable Y zeolite molecular sieves as a catalyst, the naphthalene conversion decreased from 100% to 92% after 6 hours of reaction at 200℃; when using β zeolite molecular sieves as a catalyst, the naphthalene conversion decreased from 94% to 62%. Yu Qingyue et al. (Fine Petrochemicals, 2009, Vol. 26, No. 5) found that the USY catalyst exhibited good performance in the catalytic reaction of naphthalene and isopropanol. At 150℃, the conversion rate of naphthalene can reach 92.3%, but the selectivity of 2,6-diisopropylnaphthalene in disubstituted products is only 40.3%. CN107954812A discloses a method for naphthalene alkylation in a fixed-bed reaction using silanized modified ZSM-5 / ZSM-12 composite molecular sieve as a catalyst, but the selectivity of 2,6-DIPN is only 41%. Therefore, improving the selectivity of 2,6-diisopropylnaphthalene is the key to its preparation. Summary of the Invention

[0004] Based on the above analysis, the present invention aims to provide an alkali-modified USY molecular sieve, its preparation method and application, and a method for preparing 2,6-diisopropylnaphthalene, in order to solve the technical problem of low selectivity of 2,6-diisopropylnaphthalene in the prior art.

[0005] The objective of this invention is mainly achieved through the following technical solutions.

[0006] In a first aspect, the present invention provides a method for preparing alkali-modified USY molecular sieve, comprising: preparing a mixed alkali solution including an inorganic alkali and a quaternary ammonium alkali; immersing the USY molecular sieve in the mixed alkali solution for alkali treatment; filtering; washing; drying; and calcining to obtain the alkali-modified USY molecular sieve.

[0007] This invention employs a mixed alkaline solution comprising an inorganic base and an organic quaternary ammonium base to modify USY molecular sieves. While the inorganic base exhibits rapid desilication, it reduces thermal stability; the quaternary ammonium base, on the other hand, has a relatively slower desilication rate, which is easily controlled, and eliminates the need for subsequent ammonium exchange. The combined use of these two alkaline treatments on USY molecular sieves allows for moderate modification of the pore structure and acidity while maintaining the sieve's framework structure, thereby improving its catalytic efficiency and lifespan.

[0008] The preparation method of alkali-modified USY molecular sieve provided by this invention is simple in steps, low in cost, and has potential economic benefits.

[0009] According to some embodiments of the present invention, the inorganic base includes sodium hydroxide.

[0010] According to some embodiments of the present invention, the substituents of the quaternary ammonium base may be the same or different, and each may be independently selected from C1 to C2. 10 Alkyl groups, preferably C1 to C6 alkyl groups.

[0011] According to some embodiments of the present invention, the quaternary ammonium base includes at least one of tetrabutylammonium hydroxide, tetrapropylammonium hydroxide, tetraethylammonium hydroxide, and tetramethylammonium hydroxide.

[0012] According to some embodiments of the present invention, the molar ratio of the quaternary ammonium base to the inorganic base is 0.1 to 2, preferably 0.2 to 1.

[0013] According to some embodiments of the present invention, the OH in the mixed alkaline solution - The concentration is 0.1–1 mol / L, preferably 0.1–0.6 mol / L.

[0014] According to some embodiments of the present invention, the molar ratio (silicon-aluminum ratio) of SiO2 to Al2O3 in the USY molecular sieve is 5 to 200, for example, it can be 5, 6, 7, 10, 15, 20, 25, 28, 30, 35, 40, 45, 50, 55, 60, 65, 70, 72, 78, 80, 83, 85, 90, 95, 100, 120, 130, 145, 150, 165, 180, 200, etc.

[0015] According to some embodiments of the present invention, the molar ratio (silicon-aluminum ratio) of SiO2 to Al2O3 in the USY molecular sieve is 5 to 100.

[0016] According to some embodiments of the present invention, the conditions for the alkali treatment include: the temperature of the alkali treatment is 50-100°C, preferably 60-80°C; and the time of the alkali treatment is 10-240 min, preferably 30-120 min.

[0017] According to some embodiments of the present invention, the drying conditions include: a drying temperature of 60–140°C, preferably 80–120°C; and a drying time of 8–24 h, preferably 12–18 h.

[0018] According to some embodiments of the present invention, the calcination conditions include: a calcination temperature of 400–700°C, preferably 500–650°C; and a calcination time of 3–10 h, preferably 3–8 h.

[0019] Secondly, the present invention provides an alkali-modified USY molecular sieve, which is prepared by the preparation method described in the first aspect.

[0020] Thirdly, the present invention provides the application of the alkali-modified USY molecular sieve described in the second aspect in the preparation of 2,6-diisopropylnaphthalene by reacting a naphthalene source with propylene, wherein the naphthalene source includes naphthalene and / or 2-isopropylnaphthalene.

[0021] The alkali-modified USY molecular sieve provided by this invention can be applied to the reaction of naphthalene and / or 2-isopropylnaphthalene with propylene to prepare 2,6-diisopropylnaphthalene. It has the advantages of high naphthalene source conversion rate and high selectivity for 2,6-diisopropylnaphthalene, and has good reusability, allowing it to be reused multiple times.

[0022] Fourthly, the present invention provides a method for preparing 2,6-diisopropylnaphthalene, comprising: reacting a naphthalene source including naphthalene and / or 2-isopropylnaphthalene with propylene in the presence of an alkali-treated USY molecular sieve to obtain 2,6-diisopropylnaphthalene.

[0023] The method for preparing 2,6-diisopropylnaphthalene provided by this invention uses alkali-treated USY molecular sieve as a catalyst. Alkali treatment of USY molecules can remove amorphous silicon and aluminum species from the outer surface of the molecular sieve, while generating mesopores and preserving the microporous structure to the maximum extent, thereby obtaining a high naphthalene source conversion rate and 2,6-diisopropylnaphthalene yield.

[0024] According to some embodiments of the present invention, the alkali-treated USY molecular sieve is prepared by impregnating the USY molecular sieve with an alkali solution.

[0025] In this invention, the alkaline solution used in the preparation of USY molecular sieves by alkaline treatment can be prepared using various inorganic bases and organic bases (such as quaternary ammonium bases).

[0026] According to some embodiments of the present invention, the OH in the alkaline solution - The concentration is 0.1–1 mol / L, preferably 0.2–0.6 mol / L.

[0027] According to some embodiments of the present invention, the conditions for the impregnation treatment include: the temperature of the impregnation treatment is 50-100°C, preferably 60-80°C; and the time of the impregnation treatment is 10-240 min.

[0028] According to some embodiments of the present invention, the impregnated USY molecular sieve is subjected to sequential filtration, washing, drying and calcination.

[0029] According to some embodiments of the present invention, the calcination conditions include: a calcination temperature of 400–700°C, preferably 500–650°C; and a calcination time of 3–10 h, preferably 5–8 h.

[0030] According to some embodiments of the present invention, the alkali-treated USY molecular sieve includes the alkali-modified USY molecular sieve described in the second aspect.

[0031] In the provided method for preparing 2,6-diisopropylnaphthalene, the alkali-modified USY molecular sieve described in the second aspect is used as a catalyst. Compared with alkali-treated USY molecular sieves prepared by other methods, it can have higher catalytic activity, better selectivity for 2,6-diisopropylnaphthalene, and a longer catalyst life.

[0032] According to some embodiments of the present invention, the molar ratio of the naphthalene source to propylene is 1:1 to 1:5, preferably 1:1 to 1:3.

[0033] According to some embodiments of the present invention, the mass of the alkali-treated USY molecular sieve is 0.2% to 20% of the mass of the naphthalene source, preferably 1% to 15%.

[0034] According to some embodiments of the present invention, the reaction temperature is 150–300°C, preferably 170–270°C, and more preferably 190–250°C.

[0035] According to some embodiments of the present invention, the reaction time is 1 to 10 hours, preferably 3 to 8 hours.

[0036] According to some embodiments of the present invention, the pressure of the reaction is 0.5 to 6 MPa, preferably 1 to 4 MPa.

[0037] According to some embodiments of the present invention, the reaction is carried out in a reactor, which is selected from any one of a batch reactor, a fixed-bed reactor, and a slurry-bed reactor.

[0038] Compared with the prior art, the present invention can achieve at least the following beneficial effects:

[0039] This invention applies alkali-treated USY molecular sieves to the reaction of naphthalene and / or 2-isopropylnaphthalene with propylene to prepare 2,6-diisopropylnaphthalene, which has the advantages of high naphthalene source conversion and high selectivity for 2,6-diisopropylnaphthalene. In particular, the alkali-modified USY molecular sieve prepared by alkali treatment of USY molecular sieves with a mixed alkali solution including inorganic alkali and quaternary ammonium alkali can further improve the naphthalene source conversion and 2,6-diisopropylnaphthalene selectivity, and has good reusability, allowing it to be reused multiple times. Detailed Implementation

[0040] To make the technical problem to be solved, the technical solution, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely for illustrating this patent and do not limit the scope of protection of this invention in any way.

[0041] Unless otherwise defined, the technical terms used in the following embodiments have the same meaning as commonly understood by those skilled in the art. Unless otherwise specified, the reagents used in the following embodiments are conventional biochemical reagents; the raw materials, instruments, and equipment used in the following embodiments can all be obtained commercially or by existing methods; unless otherwise specified, the reagent dosages are those used in routine experimental operations; unless otherwise specified, the experimental methods are conventional methods.

[0042] The qualitative and quantitative analyses of the products in the various embodiments and comparative examples of this invention were performed offline using a Shimadzu GC-2030 gas chromatograph, with separation using an HP-INNOWAX column and detection analysis using a flame ionization detector.

[0043] Naphthalene conversion rate = (number of moles of naphthalene converted / total number of moles of naphthalene) × 100%.

[0044] DIPN selectivity = (number of moles of DIPN in the product / total number of moles of the product) × 100%.

[0045] 2,6-DIPN selectivity = (number of moles of 2,6-DIPN in the product / total number of moles of DIPN in the product) × 100%.

[0046] 2,7-DIPN selectivity = (number of moles of 2,7-DIPN in the product) / (total number of moles of DIPN in the product) × 100%.

[0047] The USY molecular sieves used in the various embodiments and comparative examples of this invention are commercially available products manufactured by Zhuoran Environmental Protection Technology (Dalian) Co., Ltd., with silicon-aluminum ratios (molar ratios of SiO2 and Al2O3) of 8, 15, 20, 35, 50, and 100, respectively, namely USY-8, USY-15, USY-20, USY-35, USY-50, and USY-100.

[0048] Example 1

[0049] (1) Prepare OH according to a molar ratio of tetrabutylammonium hydroxide and sodium hydroxide of 0.6. - A mixed solution with a concentration of 0.2 mol / L was prepared. 10 g of USY-8 molecular sieve was added to the mixed solution at a solid-liquid ratio of 1 g: 10 mL. The mixture was stirred at 70 °C for 1 h, quenched in ice water, filtered, washed with deionized water until neutral, and the filter cake was dried at 80 °C for 12 h and then calcined in a muffle furnace at 550 °C for 4 h to obtain alkali-treated USY-8 molecular sieve.

[0050] (2) 8g of alkali-treated USY-8 molecular sieve catalyst was placed in a 200mL high-pressure reactor, and then 80g of naphthalene was added. After sealing and purging with nitrogen, the pressure was increased to 0.3MPa with nitrogen. After heating to 150℃, 52.6g of gaseous propylene was introduced. The reaction temperature was controlled at 230℃, the reaction pressure was 1.5MPa, and the reaction time was 3h. The reaction results are shown in Table 1.

[0051] Example 2

[0052] (1) Prepare OH according to a molar ratio of tetraethylammonium hydroxide and sodium hydroxide of 0.4. - A mixed solution with a concentration of 0.15 mol / L was prepared. 10 g of USY-8 molecular sieve was added to the mixed solution at a solid-liquid ratio of 1 g: 10 mL. The mixture was stirred at 80 °C for 1.5 h, quenched in ice water, filtered, washed with deionized water until neutral, and the filter cake was dried at 80 °C for 16 h and then calcined in a muffle furnace at 600 °C for 5 h to obtain alkali-treated USY-8 molecular sieve.

[0053] (2) 4g of alkali-treated USY-8 molecular sieve catalyst was placed in a 200mL high-pressure reactor, and then 80g of naphthalene was added. After sealing and purging with nitrogen, the pressure was increased to 0.2MPa with nitrogen. The reactor was heated to 170℃, and 60g of gaseous propylene was introduced. The reaction temperature was controlled at 210℃, the reaction pressure was 2MPa, and the reaction time was 4h. The reaction results are shown in Table 1.

[0054] Example 3

[0055] (1) Prepare OH according to a molar ratio of tetraethylammonium hydroxide and sodium hydroxide of 0.2. - A mixed solution with a concentration of 0.1 mol / L was prepared. 5 g of USY-8 molecular sieve was added to the mixed solution at a solid-liquid ratio of 1 g: 10 mL. The mixture was stirred at 70 °C for 1 h, quenched in ice water, filtered, washed with deionized water until neutral, and the filter cake was dried at 80 °C for 14 h and then calcined in a muffle furnace at 650 °C for 3 h to obtain alkali-treated USY-8 molecular sieve.

[0056] (2) 2g of alkali-treated USY-8 molecular sieve catalyst was placed in a 200mL high-pressure reactor, and then 80g of naphthalene was added. After sealing and purging with nitrogen, the pressure was increased to 0.3MPa with nitrogen. After heating to 150℃, 52.6g of gaseous propylene was introduced. The reaction temperature was controlled at 230℃, the reaction pressure was 1.5MPa, and the reaction time was 3h. The reaction results are shown in Table 1.

[0057] Example 4

[0058] (1) The preparation process of alkali-treated molecular sieves is the same as in Example 1, except that USY-8 molecular sieve is replaced with USY-15 molecular sieve.

[0059] (2) The reaction process for preparing 2,6-DIPN was as described in Example 1. The reaction results are shown in Table 1.

[0060] Example 5

[0061] (1) The preparation process of alkali-treated molecular sieves is the same as in Example 1, except that USY-8 molecular sieve is replaced with USY-20 molecular sieve.

[0062] (2) The reaction process for preparing 2,6-DIPN was as described in Example 1. The reaction results are shown in Table 1.

[0063] Example 6

[0064] (1) The preparation process of alkali-treated molecular sieves is the same as in Example 1, except that USY-8 molecular sieve is replaced with USY-35 molecular sieve.

[0065] (2) The reaction process for preparing 2,6-DIPN was as described in Example 1. The reaction results are shown in Table 1.

[0066] Example 7

[0067] (1) The preparation process of alkali-treated molecular sieves is the same as in Example 1, except that USY-8 molecular sieve is replaced with USY-50 molecular sieve.

[0068] (2) The reaction process for preparing 2,6-DIPN was as described in Example 1. The reaction results are shown in Table 1.

[0069] Example 8

[0070] (1) The preparation process of alkali-treated molecular sieves is the same as in Example 1, except that USY-8 molecular sieve is replaced with USY-100 molecular sieve.

[0071] (2) The reaction process for preparing 2,6-DIPN was as described in Example 1. The reaction results are shown in Table 1.

[0072] Example 9

[0073] (1) The preparation process of alkali-treated USY-8 molecular sieve is the same as in Example 1, except that: "OH" is prepared according to the molar ratio of tetrabutylammonium hydroxide and sodium hydroxide of 0.6. - Replace "a mixed solution with a concentration of 0.2 mol / L" with "an OH solution prepared using sodium hydroxide". - "An alkaline solution with a concentration of 0.2 mol / L".

[0074] (2) The reaction process for preparing 2,6-DIPN was as described in Example 1. The reaction results are shown in Table 1.

[0075] Example 10

[0076] (1) The preparation process of alkali-treated USY-8 molecular sieve is the same as in Example 1, except that: "OH" is prepared according to the molar ratio of tetrabutylammonium hydroxide and sodium hydroxide of 0.6. - Replace "a mixed solution with a concentration of 0.2 mol / L" with "an OH solution prepared using tetrabutylammonium hydroxide". - "An alkaline solution with a concentration of 0.2 mol / L".

[0077] (2) The reaction process for preparing 2,6-DIPN was as described in Example 1. The reaction results are shown in Table 1.

[0078] Example 11

[0079] (1) The preparation process of alkali-treated USY-8 molecular sieve is the same as in Example 1, except that tetrabutylammonium hydroxide is replaced with tetraoctylammonium hydroxide.

[0080] (2) The reaction process for preparing 2,6-DIPN was as described in Example 1. The reaction results are shown in Table 1.

[0081] Comparative Example 1

[0082] 8g of USY-8 molecular sieve catalyst was placed in a 200mL high-pressure reactor, followed by the addition of 80g of naphthalene. The reactor was sealed, purged with nitrogen, and pressurized to 0.3MPa. The reactor was heated to 150℃, and gaseous propylene was introduced. The reaction temperature was controlled at 230℃, and the reaction pressure was 1.5MPa. After 52.6g of propylene was introduced, the reaction time was stopped, and the reaction time was 3 hours. The reaction results are shown in Table 1.

[0083] Comparative Example 2

[0084] (1) The process of alkali treatment of molecular sieve is the same as in Example 1, except that USY-8 molecular sieve is replaced with Al-MCM-41 molecular sieve (silicon-aluminum ratio is 8).

[0085] (2) The reaction process for preparing 2,6-DIPN was as described in Example 1. The reaction results are shown in Table 1.

[0086] Comparative Example 3

[0087] (1) The process of alkali treatment of molecular sieve is the same as in Example 1, except that USY-8 molecular sieve is replaced with NaY molecular sieve (silicon-aluminum ratio is 20).

[0088] (2) The reaction process for preparing 2,6-DIPN was as described in Example 1. The reaction results are shown in Table 1.

[0089] Table 1. Naphthalene conversion and 2,6-DIPN selectivity for each example and comparative example.

[0090]

[0091]

[0092] As shown in Table 1, the methods for preparing 2,6-diisopropylnaphthalene by isopropylation of naphthalene with propylene in each embodiment of the present invention all achieved high naphthalene conversion and 2,6-DIPN selectivity.

[0093] The USY-8 molecular sieves treated with alkali in Examples 2 and 9 were used to repeat the experiment ten times, following the method for preparing 2,6-DIPN in Example 2. The results are shown in Tables 2 and 3, respectively.

[0094] Table 2. Evaluation results of the reusability of the catalyst in Example 2.

[0095]

[0096] Table 3. Evaluation results of the reusability of the catalyst in Example 9

[0097]

[0098]

[0099] As shown in Tables 2-3, the alkali-treated USY molecular sieve of Example 2, when used in the reaction to prepare 2,6-diisopropylnaphthalene, did not show a significant decrease in catalytic performance after ten uses, demonstrating better reusability than the alkali-treated USY molecular sieve of Example 9. This indicates that treating the USY molecular sieve with a mixed alkali solution of inorganic and organic quaternary ammonium alkali is more beneficial for improving the catalyst's lifespan.

[0100] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A method for preparing alkali-modified USY molecular sieve, characterized in that, include: A mixed alkaline solution comprising an inorganic base and a quaternary ammonium base is prepared. The USY molecular sieve is then immersed in the mixed alkaline solution for alkaline treatment, followed by filtration, washing, drying, and calcination to obtain the alkaline-modified USY molecular sieve.

2. The preparation method according to claim 1, characterized in that, The inorganic base includes sodium hydroxide; And / or, the substituents of the quaternary ammonium bases may be the same or different, each independently selected from C1 to C2. 10 Alkyl groups, preferably C1 to C6 alkyl groups; more preferably, the quaternary ammonium base includes at least one of tetrabutylammonium hydroxide, tetrapropylammonium hydroxide, tetraethylammonium hydroxide, and tetramethylammonium hydroxide; And / or, the molar ratio of the quaternary ammonium base to the inorganic base is 0.1 to 2, preferably 0.2 to 1; And / or, the OH in the mixed alkaline solution - The concentration is 0.1–1 mol / L, preferably 0.1–0.6 mol / L; And / or, the molar ratio of SiO2 to Al2O3 in the USY molecular sieve is 5 to 200, preferably 5 to 100.

3. The preparation method according to claim 1 or 2, characterized in that, The conditions for the alkali treatment include: the temperature of the alkali treatment is 50-100℃, preferably 60-80℃; the time of the alkali treatment is 10-240 min, preferably 30-120 min. And / or, the drying conditions include: a drying temperature of 60–140°C, preferably 80–120°C; And / or, the calcination conditions include: a calcination temperature of 400–700°C, preferably 500–650°C; and a calcination time of 3–10 h, preferably 3–8 h.

4. An alkali-modified USY molecular sieve, prepared by the preparation method described in any one of claims 1-3.

5. The application of the alkali-modified USY molecular sieve according to claim 4 in the preparation of 2,6-diisopropylnaphthalene by reacting a naphthalene source with propylene, wherein the naphthalene source includes naphthalene and / or 2-isopropylnaphthalene.

6. A method for preparing 2,6-diisopropylnaphthalene, characterized in that, include: A naphthalene source, including naphthalene and / or 2-isopropylnaphthalene, reacts with propylene in the presence of an alkaline-treated USY molecular sieve to yield 2,6-diisopropylnaphthalene.

7. The method according to claim 6, characterized in that, The alkali-treated USY molecular sieve includes the alkali-modified USY molecular sieve as described in claim 4.

8. The method according to claim 6 or 7, characterized in that, The molar ratio of the naphthalene source to propylene is 1:1 to 1:5, preferably 1:1 to 1:3; And / or, the mass of the alkali-treated USY molecular sieve is 0.2% to 20% of the naphthalene source mass, preferably 1% to 15%.

9. The method according to any one of claims 6-8, characterized in that, The reaction temperature is 150–300°C, preferably 170–270°C, and more preferably 190–250°C; And / or, the pressure of the reaction is 0.5 to 6 MPa, preferably 1 to 4 MPa.

10. The method according to any one of claims 6-9, characterized in that, The reaction is carried out in a reactor, which is selected from any one of a batch reactor, a fixed-bed reactor, or a slurry-bed reactor.

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