Dihydric alcohol production method

Abstract

The invention belongs to the field of fine chemical engineering, and particularly relates to a production method of dihydric alcohol, which comprises the following steps: a) olefin, hydrogen peroxide, a titanium silicalite molecular sieve catalyst and a solvent form a uniform system through a static mixer, then the uniform system is sent to a dynamic tubular reactor for epoxidation reaction, and a reaction product is subjected to liquid-solid separation, a liquid phase obtained through separation is sent to a first rectifying tower; b) separating light and heavy components from the liquid phase through a first rectifying tower, and sending the separated heavy components to a microreactor; and c) carrying out hydrolysis reaction on the heavy components in the microreactor, and carrying out second rectification on the reacted material to separate light and heavy components, thereby obtaining a heavy component, namely a dihydric alcohol product. According to the method provided by the invention, a static mixer and continuous equipment are adopted, so that the mixing and dissolving effect of raw materials is enhanced, introduction of formic acid is avoided, and the problem of introduction of impurities is solved from the source; and meanwhile, the method does not adopt an acid / alkali catalyst, so that the introduction of sensitizers is avoided, the process flow is shortened, and the production efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of fine chemical industry, and particularly relates to a production method of diols. BACKGROUND

[0002] 1,2-pentanediol is an important organic intermediate, which is used for the synthesis of propiconazole, an economic crop special fungicide; has excellent moisturizing performance and preservative effect, and is used in various skin care products such as skin cream, eye cream, skin care water, baby care products, sunscreen, and is also an important raw material for producing polyester fibers, surfactants, pharmaceuticals and other products.

[0003] 1,2-hexanediol is widely used in ink for color inkjet printers, cosmetics, multipurpose cleaners, etc., and high-purity 1,2-hexanediol is used as a moisturizing agent for cosmetics.

[0004] 1,2-octanediol is a colorless liquid or white solid, which is widely used as an organic fine chemical raw material and an important pharmaceutical intermediate. It can be used to synthesize royal acid, non-coagulation biological materials, liquid crystal materials, biodegradable functional polymer materials, etc. It can also be widely used as an intermediate to produce various fragrances, cosmetics, plasticizers, adhesives, UV coating raw materials, additives and high-grade ink products.

[0005] At present, the method for preparing diols generally uses alpha olefin, formic acid and hydrogen peroxide as raw materials for peroxidation reaction to produce epoxy alkane. However, it is necessary to separate the epoxy alkane by esterification / acid-base neutralization reaction, and then to produce diols by hydrolysis process under the action of acidic / alkaline catalyst. The process flow is relatively long, the heat release in the reaction process is obvious, and there will be residues such as peroxymonocarbonate, ethyl formate and ethyl acetate, which will stimulate the skin and cause skin allergy and other problems. Therefore, additional refining and purification process is generally needed to achieve the product of cosmetic grade.

[0006] In order to avoid the introduction of acid from the oxidation section, many researchers have developed solid catalyst systems to realize the preparation of diols by oxidation + hydrolysis process. CN 110590507 A reports that 1-hexene and hydrogen peroxide are used in an emulsified state, and the conversion rate of 1-hexene is 95%, the selectivity of 1,2-hexanediol is 98%, and the purity is 99.5% by using resin catalyst. However, the excess of raw material hydrogen peroxide will lead to the residue of hydrogen peroxide in the water phase after the reaction, which will decompose to produce oxygen at higher than 60℃. Since alpha olefins are flammable substances, they are easy to produce explosion interval, so a large amount of nitrogen is needed for dilution during industrial conversion, which undoubtedly increases the safety risk and auxiliary material cost. CN102010293A reports that 1-pentene and 30% hydrogen peroxide are used in a reaction kettle one-pot reaction under the action of titanium-silicon molecular sieve with methanol or acetonitrile as solvent. However, the safety factor of intermittent reaction is low, which is not conducive to industrialization. SUMMARY

[0007] Therefore, the purpose of the present application is to provide a glycol production method, which uses a static mixer and continuous equipment to enhance the miscibility of raw materials, avoids the introduction of formic acid, and solves the problem of impurity introduction from the source; at the same time, the method does not use acid / base catalysts, avoids the introduction of allergens, shortens the process flow, and improves production efficiency.

[0008] The present application provides a glycol production method, comprising the following steps:

[0009] a) passing an olefin, hydrogen peroxide, a titanium silicalite catalyst, and a solvent through a static mixer to form a uniform system, and then sending it to a dynamic tubular reactor for epoxidation reaction; the reaction product is subjected to liquid-solid separation, the separated catalyst solid is recycled, and the separated liquid phase is sent to a first rectifying column;

[0010] b) the liquid phase is separated into light and heavy components by the first rectifying column, the separated light component is returned to the static mixer, and the separated heavy component is sent to a microreactor;

[0011] c) the heavy component is subjected to a hydrolysis reaction in the microreactor, and the reaction completed material is subjected to separation of light and heavy components by a second rectifying column, the separated light component is returned to the microreactor, and the separated heavy component is the glycol product.

[0012] Preferably, the olefin is C4-C8 olefin; the concentration of hydrogen peroxide is 25-75wt%; and the solvent is one or more of acetone, methanol, acetonitrile, and tert-butanol.

[0013] Preferably, the molar ratio of the olefin to H2O2 in the hydrogen peroxide is (2-10):1.

[0014] Preferably, the mass ratio of the solvent to the olefin is (3-10):1.

[0015] Preferably, the content of the titanium silicalite catalyst in the uniform system is 1-10wt%.

[0016] Preferably, the mixing time of the olefin, hydrogen peroxide, titanium silicalite catalyst, and solvent in the static mixer is 1-10min.

[0017] Preferably, the temperature of the epoxidation reaction is 40-80℃, the pressure is 0.1-1MPa, and the time is 20-60min.

[0018] Preferably, when the hydrolysis reaction is performed, the molar ratio of alkylene oxide to water in the microreactor feed is controlled to be (10-25):1.

[0019] Preferably, the temperature of the hydrolysis reaction is 110-160℃; the residence time of the material in the microreactor is 20-60min.

[0020] Preferably, the microreactor is a dynamic tubular reactor, a microchannel reactor, or a bubble reactor.

[0021] Compared with the prior art, the present application provides a production method of dihydric alcohol, comprising the following steps: a) passing an olefin, hydrogen peroxide, a titanium silicalite catalyst, and a solvent through a static mixer to form a uniform system, and then sending the system to a dynamic tubular reactor to perform an epoxidation reaction, performing liquid-solid separation on the reaction product, recycling the separated catalyst solid, and sending the separated liquid phase to a first rectifying column; b) separating light and heavy components from the liquid phase through the first rectifying column, returning the separated light component to the static mixer, and sending the separated heavy component to a microreactor; c) performing a hydrolysis reaction on the heavy component in the microreactor, separating light and heavy components from the material after the reaction through a second rectifying column, returning the separated light component to the microreactor, and obtaining the dihydric alcohol product from the separated heavy component. The method provided by the present application strengthens the miscibility of raw materials by using a static mixer and a continuous device, avoids the introduction of formic acid, solves the problem of the introduction of impurities from the source, does not use an acid / alkali catalyst, avoids the introduction of allergens, shortens the process flow, and improves the production efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of the provided drawings.

[0023] Figure 1 is a process flow chart provided by the embodiments of the present application. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0025] The present application provides a production method of dihydric alcohol, as shown in Figure 1 , comprising the following steps:

[0026] a) passing the olefin, hydrogen peroxide, titanium silicalite catalyst and solvent through a static mixer to form a homogeneous system, and then sending the system to a dynamic tubular reactor to perform an epoxidation reaction, performing liquid-solid separation on the reaction product, recycling the separated catalyst solid, and sending the separated liquid phase to a first rectifying column;

[0027] b) separating the light and heavy components of the liquid phase through the first rectifying column, returning the separated light component (unreacted olefin, solvent and part of the water phase) to the static mixer, and sending the separated heavy component (remaining water phase and alkylene oxide) to a microreactor;

[0028] c) performing a hydrolysis reaction on the heavy component in the microreactor, separating the light and heavy components of the reaction product through a second rectifying column, returning the separated light component (water) to the microreactor, and obtaining the diol product as the separated heavy component.

[0029] In the production method provided by the application, the olefin is preferably a C4-C8 olefin, more preferably a C5 olefin, a C6 olefin or a C8 olefin.

[0030] In the production method provided by the application, the concentration of the hydrogen peroxide is preferably 25-75 wt%, and can be 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt% or 75 wt%.

[0031] In the production method provided by the application, the TiO2 content of the titanium silicalite catalyst is preferably 1-5 wt%, and can be 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt% or 5 wt%; the specific surface area of the titanium silicalite catalyst is preferably 400-500 m 2 / g, and can be 400 m 2 / g, 410 m 2 / g, 420 m 2 / g, 430 m 2 / g, 440 m 2 / g, 450 m 2 / g, 460 m 2 / g, 468 m 2 / g, 470 m 2 / g, 480 m 2 / g, 490 m 2 / g or 500 m 2 / g.

[0032] In the production method provided by the application, the solvent is preferably one or more of acetone, methanol, acetonitrile and tert-butanol, and more preferably a mixed solvent of acetone and methanol, wherein the content of methanol in the mixed solvent is preferably 1-10wt%, and specifically can be 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt% or 10wt%.

[0033] In the production method provided by the application, the molar ratio of the olefin to H2O2 in the hydrogen peroxide is preferably (2-10):1, and specifically can be 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1, 8:1, 8.5:1, 9:1, 9.5:1 or 10:1.

[0034] In the production method provided by the application, the mass ratio of the solvent to the olefin is preferably (3-10):1, and specifically can be 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1, 8:1, 8.5:1, 9:1, 9.5:1 or 10:1.

[0035] In the production method provided by the application, the content of the titanium silicalite molecular sieve catalyst in the homogeneous system is preferably 1-10wt%, and specifically can be 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, 5wt%, 5.5wt%, 6wt%, 6.5wt%, 7wt%, 7.5wt%, 8wt%, 8.5wt%, 9wt%, 9.5wt% or 10wt%.

[0036] In the production method provided by the application, the mixing time of the olefin, hydrogen peroxide, titanium silicalite molecular sieve catalyst and solvent in the static mixer is preferably 1-10min, and specifically can be 1min, 2min, 3min, 4min, 5min, 6min, 7min, 8min, 9min or 10min.

[0037] In the production method provided by the application, the temperature of the epoxidation reaction is preferably 40-80℃, and can be specifically 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃ or 80℃; the pressure of the epoxidation reaction is preferably 0.1-1 MPa, and can be specifically 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa or 1 MPa; and the time of the epoxidation reaction is preferably 20-60 min, and can be specifically 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min or 60 min.

[0038] In the production method provided by the application, the liquid-solid separation is carried out in a liquid-solid separator; the pressure during the separation is preferably 1-10 MPa, and can be specifically 1 MPa, 2 MPa, 3 MPa, 4 MPa, 5 MPa, 6 MPa, 7 MPa, 8 MPa, 9 MPa or 10 MPa; and the pore size of the filter screen is preferably 5000-20000 mesh, and can be specifically 5000 mesh, 6000 mesh, 7000 mesh, 8000 mesh, 9000 mesh, 10000 mesh, 11000 mesh, 12000 mesh, 13000 mesh, 14000 mesh, 15000 mesh, 16000 mesh, 17000 mesh, 18000 mesh, 19000 mesh or 20000 mesh.

[0039] In the production method provided by the application, when the hydrolysis reaction is carried out, the molar ratio of alkylene oxide to water in the microreactor feed is preferably controlled to be (10-25):1, and can be specifically 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, 20:1, 21:1, 22:1, 23:1, 24:1 or 25:1.

[0040] In the production method provided by the application, the microreactor is preferably a dynamic tubular reactor, a microchannel reactor or a bubble reactor.

[0041] In the production method provided by the application, the temperature of the hydrolysis reaction is preferably 110-160℃, and can be specifically 110℃, 115℃, 120℃, 125℃, 130℃, 135℃, 140℃, 145℃, 150℃, 155℃ or 160℃; and the residence time of the material in the microreactor is preferably 20-60 min, and can be specifically 20 min, 23 min, 25 min, 27 min, 30 min, 32 min, 35 min, 37 min, 40 min, 42 min, 45 min, 47 min, 50 min, 52 min, 55 min, 57 min or 60 min.

[0042] The method provided by the application enhances the mixing effect of raw materials by using a static mixer and a continuous device, avoids the introduction of formic acid, and solves the problem of the introduction of impurities from the source; meanwhile, the method does not use acid / base catalysts, avoids the introduction of allergens, shortens the process flow, and improves the production efficiency.

[0043] For a clearer understanding, the epoxidation section and the hydrolysis section involved in the technical solutions of the application are described in detail below through the following examples.

[0044] Examples 1-9

[0045] Epoxidation section

[0046] The olefin, hydrogen peroxide, catalyst and solvent are respectively pumped into the static mixer at a certain rate, and after staying in the static mixer for 1-3 min, they are pumped into the dynamic tubular reactor (size: 1200 mm x 700 mm x 1200 mm; material: C276, liquid holding capacity: 1000 mL); the pressure in the dynamic tubular reactor is controlled stable by a back pressure valve and a pressure stabilizing tank (the reaction pressure is controlled at about 0.4 MPa), and the reaction temperature is controlled stable by a cold and hot all-in-one machine; the reacted materials are subjected to liquid-solid separation by a liquid-solid separator (processing capacity: 1 L, pressure: 5 MPa, filter screen: 10000 mesh) to realize the separation of liquid and solid.

[0047] In examples 1-7, 1-pentene is used as the raw material, 30wt% hydrogen peroxide is used, 95wt% acetone + 5wt% methanol is used as the mixed solvent, titanium silicalite is used as the catalyst (TiO2 content: 3wt%, specific surface area: 468m 2 / g), and the content of the catalyst in the raw material mixture is 6wt%; in example 8, 1-hexene is used as the raw material, and in example 9, 1-octene is used as the raw material, and the other conditions are not changed. The specific data are as follows:

[0048] Table 1: Data analysis of the epoxidation section examples

[0049]

[0050] Examples 10-15

[0051] Hydrolysis section

[0052] The epoxy alkane separated from the epoxidation section and water are pumped into the microreactor according to a certain material ratio, the contact area of the two is improved by process intensification means; the reaction temperature is controlled by controlling the temperature of the heat conducting oil, and the residence time is controlled by controlling the flow rate of the pump.

[0053] The following experiments were all carried out using a dynamic tubular reactor (size: 1200 mm x 700 mm x 1200 mm; material: C276, liquid holdup: 1000 mL). Among them, examples 10-13 used epoxy pentane as raw material, example 14 used epoxy hexane as raw material, and example 15 used epoxy octane as raw material. The specific data are as follows:

[0054] Table 2 Hydrolysis section example data analysis

[0055] Serial number n water : n alkylene oxide Residence time, min Temperature, °C Conversion, % Selectivity, % Example 10 10:1 40 120 85 90 Example 11 18:1 40 120 98 99 Example 12 18:1 20 120 90 99 Example 13 18:1 40 150 99 92 Example 14 18:1 40 120 97 99 Example 15 18:1 40 120 96 99

[0056] In the above examples of the present application, the quantitative analysis of organic components was carried out by gas chromatography, specifically: Agilent G7890B gas chromatograph, HP-INNOWAX chromatographic column (250 μm x 0.25 μm x 30 m), FID detector, 25°C to 50°C at 5°C / min, 5 min, 15°C / min to 280°C, 10 min.

[0057] In the above examples of the present application, the H2O2 content in the material before and after the reaction was titrated by KMnO4 method.

[0058] The above is only the preferred embodiment of the present application, it should be noted that for those skilled in the art, without departing from the principles of the present application, can make a number of improvements and refinements, these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A method for producing a diol, characterized by, The method comprises the following steps: a) passing the olefin, hydrogen peroxide, titanium silicalite catalyst and solvent through a static mixer to form a uniform system, and then sending the system to a dynamic tubular reactor to perform an epoxidation reaction, performing liquid-solid separation on the reaction product, recycling the separated catalyst solid, and sending the separated liquid phase to a first rectifying column; b) separating the light and heavy components of the liquid phase in the first rectifying column, returning the separated light component to the static mixer, and sending the separated heavy component to a microreactor; c) performing a hydrolysis reaction on the heavy component in the microreactor, performing light-heavy component separation on the reaction product in a second rectifying column, returning the separated light component to the microreactor, and obtaining the dihydric alcohol product from the separated heavy component.

2. The production method according to claim 1, characterized by, The olefin is a C4-C8 olefin; the concentration of the hydrogen peroxide is 25-75 wt%; and the solvent is one or more of acetone, methanol, acetonitrile and tert-butanol.

3. The production method according to claim 1, characterized by, The molar ratio of the olefin to H2O2 in the hydrogen peroxide is (2-10):

1.

4. The production method according to claim 1, characterized by, The mass ratio of the solvent to the olefin is (3-10):

1.

5. The production method according to claim 1, characterized by, The content of the titanium silicalite catalyst in the uniform system is 1-10 wt%.

6. The production method according to claim 1, characterized by, The mixing time of the olefin, hydrogen peroxide, titanium silicalite catalyst and solvent in the static mixer is 1-10 min.

7. The production method according to claim 1, characterized by, The temperature of the epoxidation reaction is 40-80℃, the pressure is 0.1-1 MPa, and the time is 20-60 min.

8. The production method according to claim 1, characterized by, When the hydrolysis reaction is performed, the molar ratio of the alkylene oxide to water in the microreactor feed is controlled to be (10-25):

1.

9. The production method according to claim 1, characterized by, The temperature of the hydrolysis reaction is 110-160℃, and the residence time of the material in the microreactor is 20-60 min.

10. The production method according to claim 1, characterized by, The microreactor is a dynamic tubular reactor, a microchannel reactor or a bubbling reactor.

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