A process for the preparation of isobutylbenzene from benzene and isobutanol

Abstract

The application provides a method for preparing isobutylbenzene from benzene and isobutyl alcohol. The method comprises: gasifying raw materials including benzene and isobutyl alcohol, and then allowing the raw materials to react in the presence of a catalyst to obtain isobutylbenzene; and the catalyst comprises nano hydrogen type X molecular sieve and gallium and / or indium supported on the nano hydrogen type X molecular sieve. The nano hydrogen type X molecular sieve loaded with gallium and / or indium is used as the catalyst, isobutylbenzene is synthesized by using the process route of allowing benzene and isobutyl alcohol to undergo alkylation reaction, the process route has simple process conditions, small safety risk, and can realize continuous production, and has wide market application prospect.

Description

Technical Field

[0001] This invention belongs to the field of isobutylbenzene synthesis technology, specifically relating to a method for preparing isobutylbenzene from benzene and isobutanol. Background Technology

[0002] Isobutylbezene (IBB) is a key intermediate in the synthesis of ibuprofen (Profe or Brufen), a human drug used for its anti-inflammatory, antipyretic, and analgesic properties. Ibuprofen, as an anti-inflammatory, antipyretic, and analgesic, can treat rheumatoid arthritis, osteoarthritis, toothache, neuralgia, and other conditions. It also has good efficacy in relieving inflammation, fever, and pain after gynecological and obstetric surgeries, with few adverse reactions, allowing for long-term use and a very broad market prospect.

[0003] In the numerous synthetic routes for ibuprofen, almost all require the intermediate isobutylbenzene. To date, there are over a dozen synthetic routes for isobutylbenzene, but most are laboratory preparation methods. Due to their low conversion efficiency or easy catalyst deactivation, they are not yet suitable for industrial production. Some synthetic methods, while industrially feasible, suffer from difficulties in obtaining the necessary raw materials. Currently, the main industrial process for isobutylbenzene synthesis involves the side-chain alkylation reaction of toluene and propylene under the catalysis of alkali metal potassium or sodium catalysts. However, this process is demanding due to the presence of free alkali metal potassium or sodium in the catalyst, the need for the addition of water or ethanol as a terminator, and the use of high temperature and pressure conditions. Furthermore, this process is typically conducted industrially using batch reactors, making continuous production impossible.

[0004] Therefore, there is an urgent need to develop a method for preparing isobutylene that is simple to operate, has low safety risks, can be synthesized continuously, and is suitable for industrial production. Summary of the Invention

[0005] Based on the above analysis, the present invention aims to provide a method for preparing isobutylbenzene from benzene and isobutanol, in order to solve the technical problems of the existing isobutylbenzene synthesis process having stringent operation requirements, high safety risks, and inability to achieve continuous production.

[0006] The objective of this invention is mainly achieved through the following technical solutions.

[0007] This invention provides a method for preparing isobutylbenzene from benzene and isobutanol, comprising: gasifying a raw material including benzene and isobutanol and reacting it in the presence of a catalyst to obtain isobutylbenzene;

[0008] The catalyst comprises a nano-hydrogen-type X molecular sieve and gallium and / or indium supported on the nano-hydrogen-type X molecular sieve.

[0009] According to some embodiments of the present invention, the mass fraction of gallium and / or indium in the catalyst is 0.1 wt% to 3 wt%, for example, it can be 0.1 wt%, 0.2 wt%, 0.4 wt%, 0.5 wt%, 0.8 wt%, 1 wt%, 1.2 wt%, 1.3 wt%, 1.5 wt%, 1.7 wt%, 1.9 wt%, 2 wt%, 2.1 wt%, 2.2 wt%, 2.4 wt%, 2.5 wt%, 2.8 wt%, 3 wt%, etc.

[0010] In the method for preparing isobutylbenzene from benzene and isobutanol provided by the present invention, the catalyst is a nano-hydrogen-type X molecular sieve simultaneously loaded with gallium and indium. Compared with nano-hydrogen-type X molecular sieves loaded only with gallium or only with indium, higher benzene conversion and isobutylbenzene selectivity can be obtained.

[0011] In this invention, gallium and / or indium supported on nano-hydrogen-type X molecular sieves generally exist in the form of oxides.

[0012] According to some embodiments of the present invention, the mass ratio of gallium to indium supported on nano-hydrogen-type X molecular sieve is (0.1 to 10):1.

[0013] According to some embodiments of the present invention, the average particle size of the nano-hydrogen-type X molecular sieve is 80-800 nm.

[0014] According to some embodiments of the present invention, the silicon-to-aluminum ratio (molar ratio of SiO2 to Al2O3, SiO2 / Al2O3) of the nano-hydrogen-type X molecular sieve is 2 to 3.

[0015] According to some embodiments of the present invention, the preparation method of the catalyst includes: subjecting nano-alkali metal X molecular sieve to at least one ion exchange treatment using an ion exchange solution containing ammonium ions, then loading gallium and / or indium onto the ion-exchange treated nano-X molecular sieve using an impregnation method, drying, and calcining to obtain the catalyst.

[0016] According to some embodiments of the present invention, the concentration of ammonium ions in the ion exchange solution is 0.25 to 3.0 mol / L, for example, it can be 0.25 mol / L, 0.3 mol / L, 0.5 mol / L, 0.6 mol / L, 0.8 mol / L, 1 mol / L, 1.2 mol / L, 1.5 mol / L, 1.8 mol / L, 2 mol / L, 2.2 mol / L, 2.5 mol / L, 2.7 mol / L, 3 mol / L, etc.

[0017] According to some embodiments of the present invention, the ion exchange solution includes at least one of ammonium nitrate solution, ammonium chloride solution, and ammonium sulfate solution.

[0018] According to some embodiments of the present invention, the nano-alkali metal X molecular sieve includes at least one of nano-sodium X molecular sieve and nano-potassium X molecular sieve.

[0019] According to some embodiments of the present invention, the mass ratio of the nano-alkali metal X molecular sieve to the ion exchange liquid is 1:(4-15).

[0020] According to some embodiments of the present invention, the temperature of the ion exchange treatment is 10–30°C and the time is 0.5–5 h.

[0021] According to some embodiments of the present invention, the gallium precursor used in the impregnation method includes gallium nitrate and / or gallium acetate.

[0022] According to some embodiments of the present invention, the indium precursor used in the impregnation method includes indium nitrate and / or indium acetate.

[0023] According to some embodiments of the present invention, the drying temperature is 100-150°C.

[0024] According to some embodiments of the present invention, the calcination temperature is 500-600°C and the calcination time is 3-10 hours.

[0025] In this invention, the nano-alkali metal X molecular sieve can be prepared using various existing preparation methods.

[0026] According to some embodiments of the present invention, the preparation method of the nano-alkali metal X molecular sieve includes: obtaining a mixture comprising alkali metal hydroxide, silicon source, aluminum source and water, wherein the molar ratio of each component in the mixture is n(alkali metal oxide):n(SiO2):n(Al2O3):n(H2O)=(2.5~6):(1.8~3.2):1:(85~120); and crystallizing, filtering and washing the mixture to obtain the nano-alkali metal X molecular sieve.

[0027] According to some embodiments of the present invention, the alkali metal hydroxide includes at least one of sodium hydroxide and potassium hydroxide.

[0028] According to some embodiments of the present invention, the alkali metal oxide includes at least one of Na2O and K2O.

[0029] According to some embodiments of the present invention, the silicon source includes sodium aluminate.

[0030] According to some embodiments of the present invention, the aluminum source includes silica sol.

[0031] According to some embodiments of the present invention, the crystallization conditions include: a crystallization temperature of 75–90°C and a crystallization time of 1.5–4 hours.

[0032] According to some embodiments of the present invention, the molar ratio of benzene to isobutanol in the raw materials is (0.5-10):1, preferably (1-8):1, and more preferably (3-6):1.

[0033] In the method for preparing isobutylbenzene from benzene and isobutanol provided by the present invention, making the benzene in the raw materials in excess can effectively reduce the decomposition loss of isobutanol.

[0034] According to some embodiments of the present invention, the mass hourly space velocity (MHSV) of the raw material is 0.5 to 5 h⁻¹. -1 Preferably 1 to 4 hours -1 .

[0035] According to some embodiments of the present invention, the reaction temperature is 150–450°C, preferably 200–400°C.

[0036] According to some embodiments of the present invention, the reaction pressure is 0 to 1 MPa, preferably 0 to 0.6 MPa.

[0037] According to some embodiments of the present invention, the reaction is carried out on a fixed bed.

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

[0039] This invention uses a nano-hydrogen-type X molecular sieve supported on gallium and / or indium as a catalyst to synthesize isobutylbenzene via an alkylation reaction of benzene and isobutanol. This process route is simple, has low safety risks, and can achieve continuous production, thus having broad market application prospects. 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] Example 1

[0043] (1) Preparation of nano-sodium X molecular sieve: Sodium hydroxide was dissolved in distilled water, and sodium aluminate was added to the sodium hydroxide solution. The mixture was stirred until clear, and then silica sol was added and stirred to mix. The molar ratio of each substance in the mixture was n(Na2O):n(SiO2):n(Al2O3):n(H2O) = 2.92:2:1:96. The mixture was placed in a stainless steel autoclave lined with polytetrafluoroethylene and ultrasonically crystallized in a water bath at 80°C for 2.5 h. The synthesized product was filtered and washed to obtain nano-sodium X molecular sieve with a SiO2 / Al2O3 ratio of 2.10 and an average particle size of 800 nm.

[0044] (2) Preparation of catalyst: The above-mentioned nano-sodium X molecular sieve was added to a 1 mol / L ammonium nitrate solution and stirred at room temperature for 2 h for ion exchange. The solid-liquid mass ratio was 1:6. It was washed with deionized water and dried at 110℃ for 10 h. Then it was immersed in gallium nitrate solution, evaporated under reduced pressure, dried at 120℃, calcined at 550℃ for 5 h, pressed into tablets, crushed, and sieved to make 20-40 mesh particles, and a catalyst with a gallium content of 1.5 wt% was obtained.

[0045] (3) Synthesis of isobutylene: 0.5 g of the catalyst obtained above was loaded into a fixed-bed reactor. Benzene and isobutanol were vaporized and passed through the fixed-bed reactor. The molar ratio of benzene to isobutanol was 5:1, the reaction temperature was 300℃, the reaction pressure was 0.1 MPa, and the feed mass hourly space velocity was 3.0 h⁻¹. -1 The reaction results are shown in Table 1.

[0046] Example 2

[0047] (1) Preparation of nano-sodium X molecular sieve: Sodium hydroxide was dissolved in distilled water, and sodium aluminate was added to the sodium hydroxide solution. The mixture was stirred until clear, and then silica sol was added and stirred to mix. The molar ratio of each substance in the mixture was n(Na2O):n(SiO2):n(Al2O3):n(H2O) = 3.57:2:1:96. The mixture was placed in a stainless steel autoclave lined with polytetrafluoroethylene and ultrasonically crystallized in a water bath at 80°C for 2.5 h. The synthesized product was filtered and washed to obtain nano-sodium X molecular sieve with a SiO2 / Al2O3 ratio of 2.07 and an average particle size of 650 nm.

[0048] (2) Preparation of catalyst: The above-mentioned nano-sodium X molecular sieve was added to a 1 mol / L ammonium nitrate solution and stirred at room temperature for 2 h for ion exchange. The solid-liquid mass ratio was 1:6. It was washed with deionized water and dried at 110℃ for 10 h. Then it was immersed in indium nitrate solution, evaporated under reduced pressure, dried at 120℃, calcined at 550℃ for 5 h, pressed into tablets, crushed, and sieved to make 20-40 mesh particles, and a catalyst with an indium content of 1.5 wt% was obtained.

[0049] (3) The method for synthesizing isobutylbenzene is as described in Example 1, and the reaction results are shown in Table 1.

[0050] Example 3

[0051] (1) Preparation of nano-sodium X molecular sieve: Sodium hydroxide was dissolved in distilled water, and sodium aluminate was added to the sodium hydroxide solution. The mixture was stirred until clear, and then silica sol was added and stirred to mix. The molar ratio of each substance in the mixture was n(Na2O):n(SiO2):n(Al2O3):n(H2O) = 4.71:2:1:96. The mixture was placed in a stainless steel autoclave lined with polytetrafluoroethylene and ultrasonically crystallized in a water bath at 80°C for 2.5 h. The synthesized product was filtered and washed to obtain nano-sodium X molecular sieve with a SiO2 / Al2O3 ratio of 2.12 and an average particle size of 400 nm.

[0052] (2) Preparation of catalyst: The above-mentioned nano-sodium X molecular sieve was added to a 1 mol / L ammonium nitrate solution and stirred at room temperature for 2 h for ion exchange. The solid-liquid mass ratio was 1:6. It was washed with deionized water and dried at 110℃ for 10 h. Then it was immersed in a solution containing gallium nitrate and indium nitrate, then evaporated under reduced pressure and dried at 120℃. It was calcined at 550℃ for 5 h, pressed into tablets, crushed, and sieved to make 20-40 mesh particles, and a catalyst with a gallium content of 0.5 wt% and an indium content of 1 wt% was obtained.

[0053] (3) The method for synthesizing isobutylbenzene is as described in Example 1, and the reaction results are shown in Table 1.

[0054] Example 4

[0055] (1) Preparation of nano-sodium X molecular sieve: Sodium hydroxide was dissolved in distilled water, and sodium aluminate was added to the sodium hydroxide solution. The mixture was stirred until clear, and then silica sol was added and stirred to mix. The molar ratio of each substance in the mixture was n(Na2O):n(SiO2):n(Al2O3):n(H2O) = 5.85:2.8:1:105. The mixture was placed in a stainless steel autoclave lined with polytetrafluoroethylene and ultrasonically crystallized in a water bath at 80°C for 2.5 h. The synthesized product was filtered and washed to obtain nano-sodium X molecular sieve with a SiO2 / Al2O3 ratio of 2.88 and an average particle size of 250 nm.

[0056] (2) Preparation of catalyst: The above-mentioned nano-sodium X molecular sieve was added to a 1 mol / L ammonium nitrate solution and stirred at room temperature for 2 h for ion exchange. The solid-liquid mass ratio was 1:6. It was washed with deionized water and dried at 110℃ for 10 h. Then it was immersed in a solution containing gallium nitrate and indium nitrate, then evaporated under reduced pressure and dried at 120℃. It was calcined at 550℃ for 5 h, pressed into tablets, crushed, and sieved to make 20-40 mesh particles, and a catalyst with a gallium content of 1 wt% and an indium content of 1.5 wt% was obtained.

[0057] (3) The method for synthesizing isobutylbenzene is as described in Example 1, and the reaction results are shown in Table 1.

[0058] Example 5

[0059] (1) Preparation of nano-sodium X molecular sieve: Sodium hydroxide was dissolved in distilled water, and sodium aluminate was added to the sodium hydroxide solution. The mixture was stirred until clear, and then silica sol was added and stirred to mix. The molar ratio of each substance in the mixture was n(Na2O):n(SiO2):n(Al2O3):n(H2O) = 5.85:2:1:105. The mixture was placed in a stainless steel autoclave lined with polytetrafluoroethylene and ultrasonically crystallized in a water bath at 80°C for 2.5 h. The synthesized product was filtered and washed to obtain nano-sodium X molecular sieve with a SiO2 / Al2O3 ratio of 2.10 and an average particle size of 120 nm.

[0060] (2) Preparation of catalyst: The above-mentioned nano-sodium type X molecular sieve was added to a 1 mol / L ammonium nitrate solution and stirred at room temperature for 2 h for ion exchange. The solid-liquid mass ratio was 1:6. It was washed with deionized water and dried at 110℃ for 10 h. Then it was immersed in a solution containing gallium nitrate and indium nitrate, then evaporated under reduced pressure and dried at 120℃. It was calcined at 550℃ for 5 h, pressed into tablets, crushed, and sieved to make 20-40 mesh particles, and a catalyst with a gallium content of 0.3 wt% and an indium content of 1.6 wt% was obtained.

[0061] (3) The method for synthesizing isobutylbenzene is as described in Example 1, and the reaction results are shown in Table 1.

[0062] Example 6

[0063] (1) Preparation of nano-sodium X molecular sieve: Sodium hydroxide was dissolved in distilled water, and sodium aluminate was added to the sodium hydroxide solution. The mixture was stirred until clear, and then silica sol was added and stirred to mix. The molar ratio of each substance in the mixture was n(Na2O):n(SiO2):n(Al2O3):n(H2O) = 5.85:2.25:1:105. The mixture was placed in a stainless steel autoclave lined with polytetrafluoroethylene and ultrasonically crystallized in a water bath at 80°C for 2.5 h. The synthesized product was filtered and washed to obtain nano-sodium X molecular sieve with a SiO2 / Al2O3 ratio of 2.31 and an average particle size of 85 nm.

[0064] (2) Preparation of catalyst: The above-mentioned nano-sodium X molecular sieve was added to a 1 mol / L ammonium nitrate solution and stirred at room temperature for 2 h for ion exchange. The solid-liquid mass ratio was 1:6. It was washed with deionized water and dried at 110℃ for 10 h. Then it was immersed in a solution containing gallium nitrate and indium nitrate, then evaporated under reduced pressure and dried at 120℃. It was calcined at 550℃ for 5 h, pressed into tablets, crushed, and sieved to make 20-40 mesh particles, and a catalyst with a gallium content of 1.8 wt% and an indium content of 0.2 wt% was obtained.

[0065] (3) The method for synthesizing isobutylbenzene is as described in Example 1, and the reaction results are shown in Table 1.

[0066] Comparative Example 1

[0067] (1) The method for preparing nano-sodium X molecular sieves is as described in Example 1.

[0068] (2) Preparation of catalyst: Take the above-mentioned nano-sodium type X molecular sieve, immerse it in gallium nitrate solution, then dry it under reduced pressure by rotary evaporation, dry it at 120℃, calcine it at 550℃ for 5h, press it into tablets, crush it, sieve it to make particles of 20-40 mesh, and obtain a catalyst with a gallium content of 1.5wt%.

[0069] (3) The method for synthesizing isobutylbenzene is as described in Example 1, and the reaction results are shown in Table 1.

[0070] Comparative Example 2

[0071] (1) Preparation of catalyst: Sodium-type X molecular sieve (Tianjin Nanhua Catalyst Co., Ltd., particle size of 30 μm) was added to 1 mol / L ammonium nitrate solution and stirred at room temperature for 2 h for ion exchange, with a solid-liquid mass ratio of 1:6; washed with deionized water and dried at 110℃ for 10 h; then immersed in gallium nitrate solution (gallium content of 0.5 wt%) for 0.5 h, then evaporated under reduced pressure and dried at 120℃, calcined at 550℃ for 5 h, pressed into tablets, crushed, and sieved to make 20-40 mesh particles, and obtained a catalyst with a gallium content of 1.5 wt%.

[0072] (2) The method for synthesizing isobutylbenzene is as described in Example 1, and the reaction results are shown in Table 1.

[0073] Comparative Example 3

[0074] (1) Preparation of catalyst: Sodium ZSM-5 molecular sieve (Tianjin Nanhua Catalyst Co., Ltd., particle size 700nm) was added to 1mol / L ammonium nitrate solution and stirred at room temperature for 2h for ion exchange, with a solid-liquid mass ratio of 1:6; washed with deionized water and dried at 110℃ for 10h; then immersed in gallium nitrate solution (gallium content 0.5wt%) for 0.5h, then evaporated under reduced pressure and dried at 120℃, calcined at 550℃ for 5h, pressed into tablets, crushed, and sieved to make 20-40 mesh particles, and obtained a catalyst with gallium content of 1.5wt%.

[0075] (2) The method for synthesizing isobutylbenzene is as described in Example 1, and the reaction results are shown in Table 1.

[0076] Comparative Example 4

[0077] (1) The method for preparing nano-sodium X molecular sieves is as described in Example 1.

[0078] (2) The method for preparing the catalyst is the same as in Example 1, except that the gallium nitrate solution is replaced with an equimolar concentration of zinc nitrate solution to obtain a catalyst with a zinc content of 1.5 wt%.

[0079] (3) The method for synthesizing isobutylbenzene is as described in Example 1, and the reaction results are shown in Table 1.

[0080] Table 1

[0081]

[0082]

[0083] Wherein, isobutanol conversion rate = (moles of isobutanol converted / moles of isobutanol fed) * 100%;

[0084] Isobutylbenzene selectivity = (moles of isobutylbenzene produced / moles of isobutanol converted) * 100%.

[0085] 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 isobutylbenzene from benzene and isobutanol, characterized in that, include: Isobutylbenzene is produced by gasifying raw materials including benzene and isobutanol and then reacting them in the presence of a catalyst. The catalyst comprises a nano-hydrogen-type X molecular sieve and gallium and / or indium supported on the nano-hydrogen-type X molecular sieve.

2. The method according to claim 1, characterized in that, The mass fraction of gallium and / or indium in the catalyst is 0.1 wt% to 3 wt%.

3. The method according to claim 1 or 2, characterized in that, The average particle size of the nano-hydrogen-type X molecular sieve is 80–800 nm.

4. The method according to any one of claims 1-3, characterized in that, The silicon-to-aluminum ratio of the nano-hydrogen-type X molecular sieve is 2 to 3.

5. The method according to any one of claims 1-4, characterized in that, The catalyst preparation method includes: subjecting nano-alkali metal X molecular sieve to at least one ion exchange treatment using an ion exchange solution containing ammonium ions, then loading gallium and / or indium onto the ion-exchange treated nano-X molecular sieve using an impregnation method, drying, and calcining to obtain the catalyst.

6. The method according to claim 5, characterized in that, The concentration of ammonium ions in the ion exchange solution is 0.25–3.0 mol / L; And / or, the ion exchange solution includes at least one of ammonium nitrate solution, ammonium chloride solution, and ammonium sulfate solution; And / or, the nano-alkali metal X molecular sieve includes at least one of nano-sodium X molecular sieve and nano-potassium X molecular sieve; And / or, the mass ratio of the nano-alkali metal X molecular sieve to the ion exchange liquid is 1:(4-15); And / or, the ion exchange treatment is performed at a temperature of 10–30°C for a time of 0.5–5 h.

7. The method according to claim 5 or 6, characterized in that, The gallium precursor used in the impregnation method includes gallium nitrate and / or gallium acetate; And / or, the indium precursor used in the impregnation method includes indium nitrate and / or indium acetate; And / or, the drying temperature is 100–150°C; And / or, the calcination temperature is 500-600℃, and the calcination time is 3-10h.

8. The method according to any one of claims 5-7, characterized in that, The preparation method of the nano-alkali metal X molecular sieve includes: obtaining a mixture comprising alkali metal hydroxide, silicon source, aluminum source and water, wherein the molar ratio of each component in the mixture is n(alkali metal oxide):n(SiO2):n(Al2O3):n(H2O)=(2.5~6):(1.8~3.2):1:(85~120); and crystallizing, filtering and washing the mixture to obtain the nano-alkali metal X molecular sieve. Preferably, the silicon source includes sodium aluminate; Preferably, the aluminum source includes silica sol; Preferably, the crystallization conditions include: a crystallization temperature of 75–90°C and a crystallization time of 1.5–4 hours.

9. The method according to any one of claims 1-8, characterized in that, The molar ratio of benzene to isobutanol in the raw material is (0.5-10):1, preferably (1-8):1, and more preferably (3-6):1; And / or, the mass hourly space velocity of the raw material is 0.5 to 5 h⁻¹. -1 Preferably 1 to 4 hours -1 .

10. The method according to any one of claims 1-9, characterized in that, The reaction temperature is 150–450°C, preferably 200–400°C; And / or, the reaction pressure is 0 to 1 MPa, preferably 0 to 0.6 MPa; And / or, the reaction is carried out on a fixed bed.

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