Method for preparing n-hexanol through continuous reaction
The method for preparing n-hexanol through continuous reaction utilizes a combination of isomeric catalysts and hydrogenation catalysts, solving the problem of difficult separation of pure products in existing technologies, achieving the preparation of high-purity n-hexanol, and reducing equipment investment and operational risks.
Patent Information
- Application Number
- CN202511535052.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-27
- Publication Date
- 2026-01-23
AI Technical Summary
Existing n-hexanol synthesis processes suffer from problems such as high requirements for raw material purity, stringent reaction conditions, complex products, and difficulties in separating pure products. These issues result in high equipment investment costs, significant operational risks, and an inability to achieve high-quality domestic production of n-hexanol.
High-purity n-hexanol is prepared by using butyl ethylene oxide as raw material and through continuous reaction of isomeric catalyst and hydrogenation catalyst. Supported catalysts and metal additives are used, including alumina and silicon oxide as supports, chromium and niobium as active metal components, and potassium and zinc as metal additives. Reaction conditions such as temperature and pressure are controlled, and post-processing includes distillation and purification.
This method achieves highly selective and stable preparation of high-purity n-hexanol, with a product purity of over 99.5%, solving the problem of difficult separation of pure products in existing technologies and reducing equipment investment and operational risks.
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to a method for continuously preparing n-hexanol, and belongs to the technical field of organic synthesis. BACKGROUND
[0002] N-hexanol is a linear higher alcohol with a six-carbon chain, has a fruity aroma, and is widely used in the fields of perfumes, food, textiles, pharmaceuticals, etc., and is a key raw material for the synthesis of the commonly used synthetic fragrance coconut aldehyde. Coconut aldehyde has a sweet coconut aroma and can be used to prepare edible essence, daily use essence, tobacco essence, and feed essence, etc., with an annual consumption of more than 5000 tons. The production process is the chemical synthesis of n-hexanol and propylene acid (ester). In addition, n-hexanol has the characteristics of high cetane number and high energy density, etc., and can be mixed with traditional diesel fuel at a high proportion, and is considered as a promising biofuel. In recent years, driven by the growth of downstream market demand, the demand for n-hexanol has increased year by year, but due to the monopoly of foreign markets, n-hexanol has long relied on high-priced imports from abroad, with an import price of more than 25000 yuan / ton. Due to the high added value and wide application prospect of n-hexanol, the synthesis of n-hexanol has always been concerned by the academic and industrial circles.
[0003] The current disclosed synthesis process of n-hexanol includes hexane oxidation method, fischer-tropsch synthesis method, hexanoic acid hydrogenation method, pentene hydroformylation method, and ziegler method, etc., but these processes often have problems such as high purity requirement of raw materials, high requirement of reaction process conditions, complex product, low selectivity of target product, and difficult separation of pure product, etc., which leads to problems such as high equipment investment cost and high operation process risk of related processes. Therefore, it is urgent to develop a new technology for producing high-quality n-hexanol, break the monopoly status of foreign markets, and realize the localization of high-quality n-hexanol. SUMMARY
[0004] In view of the deficiencies in the prior art, the present application discloses a method for continuously preparing n-hexanol, which uses butyl epoxide as a raw material, and prepares n-hexanol through continuous isomerization reaction and hydrogenation reaction under the action of isomerization catalyst and hydrogenation catalyst, respectively, and the purity of the product can reach more than 99.5%.
[0005] The technical scheme of the present application is as follows:
[0006] A method for preparing n-hexanol via a continuous reaction includes the following steps: (1) butyl ethylene oxide is isomerized under the action of an isomerization catalyst to obtain an isomerization reaction solution; (2) the isomerization reaction solution is hydrogenated under the action of a hydrogenation catalyst to obtain a hydrogenation reaction solution; (3) the hydrogenation reaction solution is post-treated to obtain n-hexanol. The isomerization catalyst is a supported catalyst, comprising a support, an active metal component, and a metal auxiliary agent. The support is one of alumina, silicon oxide, silicon nitride, silicon carbide, SBA-15, or molecular sieve. The active metal component is one or more of chromium, niobium, zirconium, molybdenum, or tungsten. The metal auxiliary agent is one or more of potassium, calcium, zinc, copper, gallium, or indium.
[0007] Based on the weight of the carrier, the loading of the active component is 1 wt.%-40 wt.%, and the loading of the metal additive is 1 wt.%-10 wt.%.
[0008] The hydrogenation catalyst is a supported catalyst or a bulk catalyst with an active metal component including at least one element selected from nickel, cobalt, copper, platinum, rhodium, palladium, ruthenium, and iridium.
[0009] In step (1), the mass hourly space velocity of the raw material is 0.1 to 10 g / g / h.
[0010] In step (1), the isomerization reaction temperature is 200-300℃ and the reaction pressure is 0.1-1.0MPa.
[0011] The mass hourly space velocity (MSV) of the isomerization reaction liquid in step (2) is 0.1-10 g / g / h;
[0012] In step (2), the hydrogenation reaction temperature is 60-150℃ and the reaction pressure is 0.1-6.0MPa.
[0013] The post-processing in step (3) includes distillation and purification steps.
[0014] The isomeric catalyst was obtained by impregnation, and the preparation method includes the following steps:
[0015] (a) Dissolve the compound containing the metal auxiliary agent in water or alcohol solvent to obtain a metal precursor salt solution;
[0016] (b) The carrier is impregnated with the modified metal precursor salt solution obtained in step (a), dried and calcined to obtain the modified carrier;
[0017] (c) Dissolve the compound containing the active metal in water or alcohol solvent to obtain an active metal precursor salt solution;
[0018] (d) Impregnate the modified support obtained in step (b) with the active precursor salt solution obtained in step (c), and then dry and calcine to obtain the catalyst.
[0019] In step (a), the metal-containing compound is selected from one or more of potassium nitrate, calcium nitrate, zinc nitrate, copper nitrate, gallium nitrate, and indium nitrate. The loading of the metal component in the additive is 1 wt.%–10 wt.% by weight of the carrier, for example, 1 wt.%, 5 wt.%, and 10 wt.%.
[0020] In step (c), the compound containing the active metal is selected from one or more of chromium nitrate, niobium oxalate, zirconium oxychloride, ammonium molybdate, and ammonium tungstate. The loading of the active component, by weight of the carrier, is 1 wt.%–40 wt.%, for example, 1 wt.%, 5 wt.%, 10 wt.%, 20 wt.%, and 40 wt.%.
[0021] In steps (b) and (d), the drying temperature is 80-120℃ and the calcination time is 12-24h.
[0022] In steps (b) and (d), the calcination temperature is 400-700℃ and the calcination time is 1-6h.
[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0024] (1) The hydrogenation reaction is carried out by directly adding a hydrogenation catalyst to the isomer reaction solution. After separation and purification, the hydrogenation reaction solution can be used to obtain high-purity n-hexanol product.
[0025] (2) In the isomerization reaction, the isomer catalyst can effectively catalyze the activation of butyl ethylene oxide. During the catalytic process, it can selectively activate CO and CC bonds, suppress side reactions such as dehydration and polymerization, and exhibit high selectivity and high stability. Detailed Implementation
[0026] The following examples will further illustrate the present invention and are intended to help readers better understand the essence of the present invention and its beneficial effects, but should not be construed as limiting the scope of the present invention.
[0027] Test methods
[0028] Gas chromatography: Agilent 8890; Injector temperature: 280℃; Split ratio: 50:1; Column: DB-5 (50m×0.25mm×0.25μm); Temperature program: 50℃ for 2 minutes, increase to 80℃ at 5℃ / min, hold for 10 minutes, increase to 300℃ at 15℃ / min, hold for 10 minutes; FID detector temperature: 300℃.
[0029] Raw materials and sources
[0030] Butyl ethylene oxide was purchased from Anaiji Chemical, with a purity >98%;
[0031] High-purity hydrogen was purchased from liquefied air, with a purity >99.999%.
[0032] The compounds of active metals and metal auxiliaries were all purchased from Aladdin Reagents, with a purity >99%;
[0033] All solvents were purchased from Aladdin Reagents, AR, with a purity >99.5%;
[0034] The carriers, alumina, silicon oxide, silicon nitride, and silicon carbide, were purchased from Sinopharm Reagent.
[0035] The carrier SBA-15 and molecular sieve were purchased from Tianjin Nanhua Catalyst Co., Ltd.
[0036] Example 1
[0037] Preparation of 3wt.%Cr-5wt.%K / Al2O3 isomer catalyst: (1) Potassium nitrate aqueous solution was prepared according to the predetermined amount, and then the alumina support was added to the potassium nitrate aqueous solution. The mixture was stirred and impregnated at room temperature for 2 hours, then transferred to an oven at 100℃ and dried for 12 hours. After that, it was transferred to a muffle furnace at 500℃ and calcined for 4 hours. After that, it was cooled to room temperature to obtain potassium-modified alumina support, denoted as K-Al; (2) Chromium nitrate aqueous solution was prepared according to the predetermined amount, and then the potassium-modified alumina support was added to the chromium nitrate aqueous solution. The mixture was stirred and impregnated at room temperature for 2 hours, then transferred to an oven at 100℃ and dried for 12 hours. After that, it was transferred to a muffle furnace at 500℃ and calcined for 4 hours. After that, it was cooled to room temperature to obtain potassium-modified alumina support supported chromium oxide catalyst, denoted as Cr-K-Al;
[0038] Isomerization reaction: A Cr-K-Al catalyst was loaded into a fixed-bed reactor. Butyl ethylene oxide was fed into the liquid phase via a horizontal flow pump. The reaction temperature was 240℃, the reaction pressure was 0.1 MPa, and the butyl ethylene oxide mass hourly space velocity (WHSV) was 0.2 h⁻¹. -1 The isomerization reaction solution is continuously extracted from the bottom of the reactor.
[0039] Hydrogenation reaction: Raney nickel catalyst was loaded into a fixed-bed reaction tube. The isomerization reaction liquid was fed into the liquid phase via a horizontal flow pump, and hydrogen was fed into the gas phase via a mass flow rate control. The reaction temperature was 80℃, the reaction pressure was 1.0 MPa, and the mass hourly space velocity (WHSV) of the isomerization reaction liquid was 1.0 h⁻¹. -1 The hydrogenation reaction liquid was continuously collected from the bottom of the reactor, and the reaction liquid was subjected to gas phase analysis. The conversion rate of butyl ethylene oxide was 40.2%, and the selectivity of n-hexanol was 90.2%.
[0040] Separation and purification: Take a predetermined amount of hydrogenation reaction liquid for distillation separation, control the vacuum degree of the distillation column to be 0.1 kPaA, the bottom temperature of the column to be 90-100℃, the top temperature of the column to be 50-60℃, and the purity of n-hexanol to be >99.5%.
[0041] Example 2
[0042] Preparation of 10wt.%Zr-1wt.%Zn / SiO2 isomer catalyst: (1) Prepare a zinc nitrate aqueous solution according to the predetermined amount, then add the silica support to the zinc nitrate aqueous solution, stir and impregnate at room temperature for 2h, then transfer to an oven at 100℃ and dry for 12h, then transfer to a muffle furnace at 500℃ and calcine for 4h, then cool to room temperature to obtain a zinc-modified silica support, denoted as Zn-Si; (2) Prepare a zirconium oxynitrate aqueous solution according to the predetermined amount, then add the zinc-modified silica support to the zirconium oxynitrate aqueous solution, stir and impregnate at room temperature for 2h, then transfer to an oven at 100℃ and dry for 12h, then transfer to a muffle furnace at 500℃ and calcine for 4h, then cool to room temperature to obtain a zinc-modified silica support supported zirconium oxide catalyst, denoted as Zr-Zn-Si;
[0043] Isomerization reaction: Zr-Zn-Si catalyst was loaded into a fixed-bed reaction tube, and butyl ethylene oxide was fed into the liquid phase via a horizontal flow pump. The reaction temperature was 240℃, the reaction pressure was 0.1 MPa, and the butyl ethylene oxide mass hourly space velocity (WHSV) was 1.0 h⁻¹. -1 The isomerization reaction solution is continuously extracted from the bottom of the reactor.
[0044] Hydrogenation reaction: Raney nickel catalyst was loaded into a fixed-bed reaction tube. The isomerization reaction liquid was fed into the liquid phase via a horizontal flow pump, and hydrogen was fed into the gas phase via a mass flow rate control. The reaction temperature was 80℃, the reaction pressure was 1.0 MPa, and the mass hourly space velocity (WHSV) of the isomerization reaction liquid was 1.0 h⁻¹. -1 The hydrogenation reaction liquid was continuously collected from the bottom of the reactor, and the reaction liquid was subjected to gas phase analysis. The conversion rate of butyl ethylene oxide was 47.2%, and the selectivity of n-hexanol was 92.3%.
[0045] Separation and purification: Take a predetermined amount of hydrogenation reaction liquid for distillation separation, control the vacuum degree of the distillation column to be 0.1 kPaA, the bottom temperature of the column to be 90-100℃, the top temperature of the column to be 50-60℃, and the purity of n-hexanol to be >99.5%.
[0046] Example 3
[0047] Preparation of 10wt.%W-3wt.%Ga / ZSM-5 heterogeneous catalyst: (1) Gallium nitrate aqueous solution was prepared according to the predetermined amount, and then ZSM-5 support was added to gallium nitrate aqueous solution. The mixture was stirred and impregnated at room temperature for 2 hours, then transferred to an oven at 100℃ for 12 hours and removed. Then it was transferred to a muffle furnace at 500℃ for 4 hours and removed. After cooling to room temperature, gallium-modified molecular sieve support was obtained, denoted as Ga-ZSM-5; (2) Ammonium tungstate aqueous solution was prepared according to the predetermined amount, and then gallium-modified molecular sieve was added to ammonium tungstate aqueous solution. The mixture was stirred and impregnated at room temperature for 2 hours, then transferred to an oven at 100℃ for 12 hours and removed. Then it was transferred to a muffle furnace at 500℃ for 4 hours and removed. After cooling to room temperature, tungsten oxide catalyst supported on gallium oxide-modified molecular sieve support was obtained, denoted as W-Ga-ZSM-5;
[0048] Isomerization reaction: W-Ga-ZSM-5 catalyst was loaded into a fixed-bed reactor. Butyl ethylene oxide was fed into the liquid phase via a horizontal flow pump. The reaction temperature was 250℃, the reaction pressure was 0.1 MPa, and the butyl ethylene oxide mass hourly space velocity (WHSV) was 2.0 h⁻¹. -1 The isomerization reaction solution is continuously extracted from the bottom of the reactor.
[0049] Hydrogenation reaction: Raney nickel catalyst was loaded into a fixed-bed reaction tube. The isomerization reaction liquid was fed into the liquid phase via a horizontal flow pump, and hydrogen was fed into the gas phase via a mass flow rate control. The reaction temperature was 80℃, the reaction pressure was 1.0 MPa, and the mass hourly space velocity (WHSV) of the isomerization reaction liquid was 1.0 h⁻¹. -1 The hydrogenation reaction liquid was continuously collected from the bottom of the reactor, and the reaction liquid was subjected to gas phase analysis. The conversion rate of butyl ethylene oxide was 51.8%, and the selectivity of n-hexanol was 90.4%.
[0050] Separation and purification: Take a predetermined amount of hydrogenation reaction liquid for distillation separation, control the vacuum degree of the distillation column to be 0.1 kPaA, the bottom temperature of the column to be 90-100℃, the top temperature of the column to be 50-60℃, and the purity of n-hexanol to be >99.5%.
[0051] Example 4
[0052] Preparation of 15wt.%Nb-10wt.%Ca / Al2O3 isomer catalyst: (1) Prepare calcium nitrate aqueous solution according to the predetermined amount, then add alumina support to calcium nitrate aqueous solution, stir and impregnate at room temperature for 2h, then transfer to oven at 100℃ for 12h and take out, then transfer to muffle furnace at 500℃ for 4h and take out, cool to room temperature to obtain calcium modified alumina support, denoted as Ca-Al; (2) Prepare niobium oxalate aqueous solution according to the predetermined amount, then add calcium modified alumina support to niobium oxalate aqueous solution, stir and impregnate at room temperature for 2h, then transfer to oven at 100℃ for 12h and take out, then transfer to muffle furnace at 500℃ for 4h and take out, cool to room temperature to obtain potassium modified alumina support supported chromium oxide catalyst, denoted as Nb-Ca-Al;
[0053] Isomerization reaction: Nb-Ca-Al catalyst was loaded into a fixed-bed reactor. Butyl ethylene oxide was fed into the liquid phase via a horizontal flow pump. The reaction temperature was 250℃, the reaction pressure was 0.1 MPa, and the butyl ethylene oxide mass hourly space velocity (WHSV) was 3.0 h⁻¹. -1 The isomerization reaction solution is continuously extracted from the bottom of the reactor.
[0054] Hydrogenation reaction: Raney nickel catalyst was loaded into a fixed-bed reaction tube. The isomerization reaction liquid was fed into the liquid phase via a horizontal flow pump, and hydrogen was fed into the gas phase via a mass flow rate control. The reaction temperature was 80℃, the reaction pressure was 1.0 MPa, and the mass hourly space velocity (WHSV) of the isomerization reaction liquid was 1.0 h⁻¹. -1 The hydrogenation reaction liquid was continuously collected from the bottom of the reactor, and the reaction liquid was subjected to gas phase analysis. The conversion rate of butyl ethylene oxide was 43.1%, and the selectivity of n-hexanol was 90.7%.
[0055] Separation and purification: Take a predetermined amount of hydrogenation reaction liquid for distillation separation, control the vacuum degree of the distillation column to be 0.1 kPaA, the bottom temperature of the column to be 90-100℃, the top temperature of the column to be 50-60℃, and the purity of n-hexanol to be >99.5%.
[0056] Example 5
[0057] Preparation of 20wt.%Mo-1wt.%In / SiC heterogeneous catalyst: (1) Prepare an aqueous solution of indium nitrate according to the predetermined amount, then add the silicon carbide support to the aqueous solution of indium nitrate, stir and impregnate at room temperature for 2h, then transfer to an oven at 100℃ and dry for 12h, then transfer to a muffle furnace at 500℃ and calcine for 4h, then cool to room temperature to obtain an indium-modified silicon carbide support, denoted as In-SiC; (2) Prepare an aqueous solution of ammonium molybdate according to the predetermined amount, then add the indium-modified silicon carbide support to the aqueous solution of ammonium molybdate, stir and impregnate at room temperature for 2h, then transfer to an oven at 100℃ and dry for 12h, then transfer to a muffle furnace at 500℃ and calcine for 4h, then cool to room temperature to obtain an indium-modified silicon carbide support supported molybdenum oxide catalyst, denoted as Mo-In-SiC;
[0058] Isomerization reaction: Mo-In-SiC catalyst was loaded into a fixed-bed reaction tube, and butyl ethylene oxide was fed into the liquid phase via a horizontal flow pump. The reaction temperature was 260℃, the reaction pressure was 0.1 MPa, and the butyl ethylene oxide mass hourly space velocity (WHSV) was 5.0 h⁻¹. -1 The isomerization reaction solution is continuously extracted from the bottom of the reactor.
[0059] Hydrogenation reaction: Raney nickel catalyst was loaded into a fixed-bed reaction tube. The isomerization reaction liquid was fed into the liquid phase via a horizontal flow pump, and hydrogen was fed into the gas phase via a mass flow rate control. The reaction temperature was 80℃, the reaction pressure was 1.0 MPa, and the mass hourly space velocity (WHSV) of the isomerization reaction liquid was 1.0 h⁻¹. -1 The liquid hourly space velocity (LHSV) for the isomerization reaction was 1.0 h⁻¹. -1 The hydrogenation reaction liquid was continuously drawn from the bottom of the reactor, and the reaction liquid was subjected to gas phase analysis. The conversion rate of butyl ethylene oxide was 46.2%, and the selectivity of n-hexanol was 91.5%.
[0060] Separation and purification: Take a predetermined amount of hydrogenation reaction liquid for distillation separation, control the vacuum degree of the distillation column to be 0.1 kPaA, the bottom temperature of the column to be 90-100℃, the top temperature of the column to be 50-60℃, and the purity of n-hexanol to be >99.5%.
[0061] Comparative Example 1
[0062] Preparation of 3wt.% Cr / Al2O3 isomeric catalyst: Chromium nitrate aqueous solution was prepared according to the predetermined amount, and then alumina support was added to the chromium nitrate aqueous solution. The mixture was stirred and impregnated at room temperature for 2 hours, then transferred to an oven at 100℃ for 12 hours and dried. After that, it was transferred to a muffle furnace at 500℃ for 4 hours and cooled to room temperature to obtain potassium-modified alumina support supported chromium oxide catalyst, denoted as Cr-Al.
[0063] Isomerization reaction: Cr-Al catalyst was loaded into a fixed-bed reaction tube, and butyl ethylene oxide was fed into the liquid phase via a horizontal flow pump. The reaction temperature was 240℃, the reaction pressure was 0.1 MPa, and the butyl ethylene oxide mass hourly space velocity (WHSV) was 0.2 h⁻¹. -1 The isomerization reaction solution is continuously extracted from the bottom of the reactor.
[0064] Hydrogenation reaction solution: Raney nickel catalyst is loaded into a fixed-bed reaction tube. The isomerization reaction solution is fed into the liquid phase via a horizontal flow pump, and hydrogen is fed into the gas phase via a mass flow rate control. The reaction temperature is 80℃, the reaction pressure is 1.0 MPa, and the mass hourly space velocity (HSV) of the isomerization reaction solution is 1.0 h⁻¹. -1 The hydrogenation reaction liquid was continuously collected from the bottom of the reactor, and the reaction liquid was subjected to gas phase analysis. The conversion rate of butyl ethylene oxide was 65.2%, and the selectivity of n-hexanol was 34.1%.
[0065] Separation and purification: Take a predetermined amount of hydrogenation reaction liquid for distillation separation, control the vacuum degree of the distillation column to be 0.1 kPaA, the bottom temperature of the column to be 90-100℃, the top temperature of the column to be 50-60℃, and the purity of n-hexanol to be >99.5%.
[0066] Comparative Example 2
[0067] Preparation of 5wt.% K / Al2O3 isomeric catalyst: Potassium nitrate aqueous solution was prepared according to the predetermined amount, and then alumina support was added to potassium nitrate aqueous solution. The mixture was stirred and impregnated at room temperature for 2 hours, then transferred to an oven at 100℃ for 12 hours and dried. After that, it was transferred to a muffle furnace at 500℃ for 4 hours and then cooled to room temperature to obtain potassium-modified alumina support, denoted as K-Al.
[0068] Isomerization reaction: K-Al catalyst was loaded into a fixed-bed reaction tube, and butyl ethylene oxide was fed into the liquid phase via a horizontal flow pump. The reaction temperature was 240℃, the reaction pressure was 0.1 MPa, and the butyl ethylene oxide mass hourly space velocity (WHSV) was 0.2 h⁻¹. -1 The isomerization reaction solution is continuously extracted from the bottom of the reactor.
[0069] Hydrogenation reaction solution: Raney nickel catalyst is loaded into a fixed-bed reaction tube. The isomerization reaction solution is fed into the liquid phase via a horizontal flow pump, and hydrogen is fed into the gas phase via a mass flow rate control. The reaction temperature is 80℃, the reaction pressure is 1.0 MPa, and the mass hourly space velocity (HSV) of the isomerization reaction solution is 1.0 h⁻¹. -1 The hydrogenation reaction solution was continuously collected from the bottom of the reactor, and the reaction solution was subjected to gas phase analysis. The conversion rate of butyl ethylene oxide was 21.6%, and the selectivity of n-hexanol was 25.3%.
[0070] Separation and purification: Take a predetermined amount of hydrogenation reaction liquid for distillation separation, control the vacuum degree of the distillation column to be 0.1 kPaA, the bottom temperature of the column to be 90-100℃, the top temperature of the column to be 50-60℃, and the purity of n-hexanol to be >99.5%.
[0071] Comparative Example 3
[0072] Preparation of 10wt.% Zr / SiO2 isomeric catalyst: Zirconium oxynitrate aqueous solution was prepared according to the predetermined amount, and then the silica support was added to the zirconium oxynitrate aqueous solution. The mixture was stirred and impregnated at room temperature for 2 hours, then transferred to an oven at 100℃ for 12 hours and dried. After that, it was transferred to a muffle furnace at 500℃ for 4 hours and then cooled to room temperature to obtain the zinc-modified silica support supported zirconium oxide catalyst, denoted as Zr-Si.
[0073] Isomerization reaction: Zr-Si catalyst was loaded into a fixed-bed reactor. Butyl ethylene oxide was fed into the liquid phase via a horizontal flow pump. The reaction temperature was 240℃, the reaction pressure was 0.1 MPa, and the butyl ethylene oxide mass hourly space velocity (WHSV) was 1.0 h⁻¹. -1 The isomerization reaction solution is continuously extracted from the bottom of the reactor.
[0074] Hydrogenation reaction solution: Raney nickel catalyst is loaded into a fixed-bed reaction tube. The isomerization reaction solution is fed into the liquid phase via a horizontal flow pump, and hydrogen is fed into the gas phase via a mass flow rate control. The reaction temperature is 80℃, the reaction pressure is 1.0 MPa, and the mass hourly space velocity (HSV) of the isomerization reaction solution is 1.0 h⁻¹. -1 The hydrogenation reaction liquid was continuously collected from the bottom of the reactor, and the reaction liquid was subjected to gas phase analysis. The conversion rate of butyl ethylene oxide was 43.2%, and the selectivity of n-hexanol was 81.4%.
[0075] Separation and purification: Take a predetermined amount of hydrogenation reaction liquid for distillation separation, control the vacuum degree of the distillation column to be 0.1 kPaA, the bottom temperature of the column to be 90-100℃, the top temperature of the column to be 50-60℃, and the purity of n-hexanol to be >99.5%.
[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for preparing n-hexanol via a continuous reaction, comprising the following steps: (1) isomerizing butyl ethylene oxide in the presence of an isomerizing catalyst to obtain an isomerizing reaction solution; (2) hydrogenating the isomerizing reaction solution in the presence of a hydrogenation catalyst to obtain a hydrogenated reaction solution; (3) post-processing the hydrogenated reaction solution to obtain the n-hexanol; wherein, The heterogeneous catalyst is a supported catalyst, comprising a support, an active metal component, and a metal promoter. The support is one of alumina, silicon oxide, silicon nitride, silicon carbide, SBA-15, and molecular sieve. The active metal component is one or more of chromium, niobium, zirconium, molybdenum, and tungsten. The metal promoter is one or more of potassium, calcium, zinc, copper, gallium, and indium.
2. The method as described in claim 1, characterized in that, The isomeric catalyst has an active component loading of 1 wt.% to 40 wt.% and a metal promoter loading of 1 wt.% to 10 wt.% based on the weight of the support.
3. The method as described in claim 1 or 2, characterized in that, The hydrogenation catalyst is a supported catalyst or a bulk catalyst with an active metal component including at least one element selected from nickel, cobalt, copper, platinum, rhodium, palladium, ruthenium, and iridium.
4. The method according to any one of claims 1-3, characterized in that, In step (1), the mass hourly space velocity of the raw material is 0.1 to 10 g / g / h; and / or, in step (1), the isomerization reaction temperature is 200 to 300 °C and the reaction pressure is 0.1 to 1.0 MPa.
5. The method according to any one of claims 1-4, characterized in that, The mass hourly space velocity of the isomerization reaction liquid in step (2) is 0.1-10 g / g / h; and / or, the hydrogenation reaction temperature in step (2) is 60-150℃ and the reaction pressure is 0.1-6.0 MPa.
6. The method according to any one of claims 1-5, characterized in that, The isomeric catalyst was obtained by impregnation. The preparation method includes the following steps: (a) Dissolve the compound containing the metal auxiliary agent in water or alcohol solvent to obtain a metal precursor salt solution; (b) The carrier is impregnated with the modified metal precursor salt solution obtained in step (a), dried and calcined to obtain the modified carrier; (c) Dissolve the compound containing the active metal in water or alcohol solvent to obtain an active metal precursor salt solution; (d) Impregnate the modified support obtained in step (b) with the active precursor salt solution obtained in step (c), and then dry and calcine to obtain the catalyst.
7. The method as described in claim 6, characterized in that, In step (a), the compound containing the metal additive is selected from one or more of potassium nitrate, calcium nitrate, zinc nitrate, copper nitrate, gallium nitrate, and indium nitrate. Based on the weight of the carrier, The loading of the auxiliary metal component is 1 wt.% to 10 wt.%, for example, 1 wt.%, 5 wt.%, and 10 wt.%.
8. The method as described in claim 6 or 7, characterized in that, In step (c), the compound containing the active metal is selected from one or more of chromium nitrate, niobium oxalate, zirconium oxychloride, ammonium molybdate, and ammonium tungstate. The loading of the active component, by weight of the carrier, is 1 wt.%–40 wt.%, for example, 1 wt.%, 5 wt.%, 10 wt.%, 20 wt.%, and 40 wt.%.
9. The method according to any one of claims 6-8, characterized in that, In steps (b) and (d), the drying temperature is 80-120℃ and the calcination time is 12-24h; and / or, in steps (b) and (d), the calcination temperature is 400-700℃ and the calcination time is 1-6h.