Method for synthesizing ethylhexylglycerin through continuous hydrolysis method and microchannel reactor

Abstract

The invention provides a method for synthesizing ethylhexylglycerin through a continuous hydrolysis method and a microchannel reactor, and relates to the technical field of preparation processes of fine chemical products. According to the method, 2-ethylhexyl glycidyl ether is taken as a raw material, under catalysis, continuous synthesis of ethylhexylglycerin is carried out through a one-step hydrolysis reaction, and a high-purity ethylhexylglycerin product is obtained through molecular rectification. Compared with the prior art, the method disclosed by the invention overcomes the defects of more byproducts, difficulty in control, poorer reaction selectivity, low product yield, tedious process, higher cost and the like caused by non-uniform reaction heating when the ethylhexylglycerin is produced and synthesized by the existing batch reactor, can realize continuous production and automatic control of the process, is efficient and safe in production, and is suitable for industrial production. The reaction conditions are mild, the reaction time is short, the selectivity is high, the product purity can reach 99.9%, the yield can reach 97% or above, and the method is green and economical and is beneficial to popularization and application of ethylhexylglycerin in cosmetics and daily chemical industries.

Description

Technical Field

[0001] The present invention relates to the technical field of preparation technology of fine chemical products, and in particular to a method for synthesizing ethylhexylglycerol by continuous hydrolysis and a microchannel reactor. Background Art

[0002] Ethylhexylglycerin is a new, multifunctional nonionic surfactant. It is a colorless, almost odorless liquid. It can be used as an antibacterial agent, deodorant, emollient, synergist, etc., and the product has biological efficacy. The LD50 of ethylhexylglycerin is > 2000 mg / kg, which has good toxicological safety. It is diluted to 50% for skin testing and has almost no irritation. In actual application, only 1% is added to have a good preservative effect. It has the characteristics of not irritating the skin and moisturizing effect, and can enhance the ability of traditional preservatives. It will play an important role in the green preservative system and is widely used in various bath products, cleaning products, deodorants, eye makeup, foundation, hair care products and sunscreen products. In addition, ethylhexylglycerin can increase the smooth skin feel while improving the moisturizing effect of emollient and moisturizing formulas. It has a synergistic effect when mixed with preservative substances. Among them, some are used in combination with traditional preservatives, and more are combined with polyols to form a "no-additive" preservative system.

[0003] As a multifunctional auxiliary agent developed in recent years, there are few reports on the synthesis process of ethylhexyl glycerol. At present, most of the domestic products are synthesized by catalytic modification hydrolysis or catalytic hydrolysis process using 2-ethylhexyl glycidyl ether as raw material. The Chinese invention patent with application number CN104817436A discloses a method for preparing high-purity ethylhexyl glycerol, which generates an intermediate 4-alkoxymethyl-1,3-dioxoalkane by using 2-ethylhexyl glycidyl ether and acetone under the catalysis of boron trifluoride ether, adds a terminator to stop the reaction, and then hydrolyzes and separates the oil phase under the catalysis of formic acid, neutralizes and washes with sodium bicarbonate, and then obtains ethylhexyl glycerol by molecular distillation. The product yield is 88% and the purity is 99%. Chinese invention patent application number CN117447315A discloses a method for preparing ethylhexyl glycerol by hydrolyzing 2-ethylhexyl glycidyl ether, wherein a water-soluble solvent such as dioxane or dimethyl sulfoxide is used, 2-ethylhexyl glycidyl ether is hydrolyzed under the catalysis of sulfuric acid, phosphotungstic acid, etc., the reaction is kept warm for a certain period of time, the reaction solution is heated and decompressed and distilled to recover the organic solvent, the concentrated solution is separated into a water layer, washed with water, and distilled to obtain ethylhexyl glycerol, the hydrolysis yield is 84.9%, and the purity is 99%.

[0004] Both of the above processes use traditional reaction kettles (bottles) for preparation. The high local heat release in the preparation process leads to more side reactions, low selectivity and yield, inability to produce continuously and complicated production operations. In addition, a large amount of acid catalyst, solvent and water are required in the synthesis, and a large amount of acidic wastewater is generated. Recovering the solvent not only increases energy consumption but also poses environmental risks, which greatly limits the promotion and use of ethylhexylglycerin as a new multifunctional additive in the cosmetics and daily chemical industries. Summary of the invention

[0005] The disclosed embodiment provides a method for synthesizing ethylhexylglycerol by continuous hydrolysis, which can solve the problems of more by-products, difficult control, poor reaction selectivity, low product yield, complicated process and high cost, increased energy consumption due to recovery of organic solvents during the synthesis process, and environmental risks when synthesizing ethylhexylglycerol in a traditional reaction bottle (kettle) due to uneven heating of the reaction. The technical solution is as follows:

[0006] According to a first aspect of an embodiment of the present disclosure, there is provided a method for synthesizing ethylhexylglycerol by a continuous hydrolysis method, the method comprising:

[0007] Step S1: adding deionized water and a catalyst into a premixing kettle according to a preset mass ratio, stirring evenly, and then pumping the mixture into a first raw material storage tank for preheating, and pumping 2-ethylhexyl glycidyl ether into a second raw material storage tank for preheating;

[0008] Step S2: pumping the deionized water and catalyst obtained in step S1 into the first preheating microchannel through a first metering pump for secondary preheating, and pumping the 2-ethylhexyl glycidyl ether obtained in step S1 into the second preheating microchannel through a second metering pump for secondary preheating; wherein the deionized water in the first preheating microchannel and the 2-ethylhexyl glycidyl ether in the second preheating microchannel are pumped in according to a preset flow volume ratio;

[0009] Step S3: sending the deionized water and catalyst obtained in step S2, and the 2-ethylhexyl glycidyl ether into a micro mixer for mixing, and sending the mixed product into a microchannel reactor for a preset time to react to synthesize ethylhexyl glycerol, and after online analysis and detection of the synthesized ethylhexyl glycerol, sending it into a product storage tank to obtain a product mixed solution;

[0010] Step S4: cooling the product mixture obtained in step S3 to room temperature to separate the organic phase component, and distilling the organic phase component under vacuum conditions using a molecular distillation device to obtain an ethylhexylglycerol product.

[0011] In one embodiment, in step S1, the catalyst is a Lewis acid catalyst, which includes any one or a combination of any two or more of zinc chloride, aluminum chloride, ferric chloride or copper chloride.

[0012] In one embodiment, in step S1, the preset mass ratio of the deionized water to the catalyst is 100:0.2-0.5; and the preheating temperatures in the first raw material storage tank and the second raw material storage tank are both 50-100°C.

[0013] In one embodiment, in step S2, the preset flow volume ratio of the deionized water in the first preheating microchannel and the 2-ethylhexyl glycidyl ether in the second preheating microchannel is 1.1-1.3:1; the temperature in the first preheating microchannel and the second preheating microchannel are both 150-250°C, and the pressure is both 0.5-4.0Mpa.

[0014] In one embodiment, in step S3, the mixed product is sent to the microchannel reactor and stays there for a preset time of 15-60 min. The controlled temperatures of the microchannel reactor and the micromixer are both 150-250° C., and the pressures are both 0.5-4.0 MPa.

[0015] In one embodiment, in step S4, the organic phase components are distilled in a molecular distillation device with a vacuum degree of 30-40 Pa, and the fraction at a temperature of 113-117° C. is collected as the target product, which is ethylhexylglycerol.

[0016] In one embodiment, in step S1, the deionized water and catalyst stirred evenly in the premixing kettle are pumped into the first raw material storage tank by the first gear pump for preheating, and 2-ethylhexyl glycidyl ether is pumped into the second raw material storage tank by the second gear pump for preheating.

[0017] In one embodiment, the first metering pump and the second metering pump are both plunger metering pumps.

[0018] According to a second aspect of an embodiment of the present disclosure, a microchannel reactor is provided, the microchannel reactor comprising: a premixing kettle, a first raw material storage tank, a second raw material storage tank, a first filter, a second filter, a first plunger metering pump, a second plunger metering pump, a first preheating microchannel, a second preheating microchannel, a micromixer, a microchannel reactor, a constant temperature oil bath, a back pressure valve, a cooling tank, an oil-water separator, a product storage tank, an online GC and a first thermal oil heating furnace; wherein,

[0019] The first interface of the first thermal oil heating furnace is connected to the first raw material storage tank through a first pipeline, and the second interface of the first thermal oil heating furnace is connected to the second raw material storage tank through a second pipeline. The first pipeline is provided with a first ball valve, and the second pipeline is provided with a first high-temperature oil pump and a second ball valve; the premixing kettle is connected to the first raw material storage tank;

[0020] The first raw material storage tank is connected to the inlet end of the first plunger metering pump through a third pipeline, the second raw material storage tank is connected to the inlet end of the second plunger metering pump through a fourth pipeline, a third ball valve and a first filter are provided on the third pipeline, and a fourth ball valve and a second filter are provided on the fourth pipeline;

[0021] The outlet end of the first plunger metering pump is connected to the inlet end of the first preheating microchannel in the constant temperature oil bath, and the outlet end of the second plunger metering pump is connected to the inlet end of the second preheating microchannel in the constant temperature oil bath;

[0022] The outlet end of the first preheating microchannel and the outlet end of the second preheating microchannel are respectively connected to the inlet end of the micromixer, the outlet end of the micromixer is connected to the inlet end of the microchannel reactor, the outlet end of the microchannel reactor is connected to the back pressure valve and then connected to the inlet end of the cooling tank, the outlet end of the cooling tank is connected to the oil-water separator, the organic phase component separated from the oil-water separator passes through the fifth pipeline and is analyzed by the online GC, and then enters the product storage tank through the sixth pipeline; wherein the fifth pipeline is provided with a fifth ball valve and a sixth ball valve, and the sixth pipeline is provided with a seventh ball valve;

[0023] The microchannel reactor is used to implement the process flow of any of the above-mentioned methods for synthesizing ethylhexylglycerol by continuous hydrolysis.

[0024] In one embodiment, the microchannel reactor also includes a second thermal oil heating furnace, which is connected to the constant temperature oil bath through a seventh pipeline and an eighth pipeline respectively, an eighth ball valve is provided on the seventh pipeline, and a ninth ball valve and a second high-temperature oil pump are provided on the eighth pipeline.

[0025] The implementation of this disclosure includes the following technical effects:

[0026] The present invention provides a method for synthesizing ethylhexylglycerol by continuous hydrolysis, which uses 2-ethylhexyl glycidyl ether and deionized water as raw materials, and continuously hydrolyzes ethylhexyl glycerol through a microchannel reactor under conditions of relatively high temperature and pressure under Lewis acid catalysis and without adding any solvent, so as to overcome the defects of synthesizing ethylhexyl glycerol in a traditional reaction flask (kettle), such as more by-products due to uneven heating of the reaction, difficulty in control, poor reaction selectivity, low product yield, complicated process and high cost, increased energy consumption due to recovery of organic solvents during the synthesis process, and environmental risks.

[0027] Compared with the prior art, the method for synthesizing ethylhexylglycerol by continuous hydrolysis disclosed in the present disclosure has the characteristics of short reaction cycle, high conversion rate and yield of target product, no solvent added in the reaction, avoiding the generation of by-products in the post-treatment process, reducing pollution to the environment, high product purity, low energy consumption, etc. Ethylhexylglycerol can be prepared by the method disclosed in the present disclosure, and a higher yield can be obtained, the product yield can reach more than 97%, the purity can reach more than 99.9%, the product appearance is a colorless transparent solution, no odor, and is better than similar products on the current market.

[0028] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A flow chart of a method for synthesizing ethylhexylglycerol by continuous hydrolysis provided in this embodiment.

[0030] Figure 2 A schematic structural diagram of a microchannel reactor provided in an embodiment of the present disclosure.

[0031] Figure 3 IR chart of ethylhexylglycerol prepared by the method for synthesizing ethylhexylglycerol by continuous hydrolysis method provided in an embodiment of the present disclosure.

[0032] Figure 4 1HNMR chart of ethylhexylglycerol prepared by the method for synthesizing ethylhexylglycerol by continuous hydrolysis provided in an embodiment of the present disclosure.

[0033] Figure 5 GC chart of ethylhexylglycerol prepared by the method for synthesizing ethylhexylglycerol by continuous hydrolysis provided in an embodiment of the present disclosure.

[0034] In the figure, 1-premixing kettle, 4-second raw material storage tank, 5-third ball valve, 6-first raw material storage tank, 7-fourth ball valve, 8-second filter, 9-second plunger metering pump, 10-first filter, 11-first plunger metering pump, 12-second preheating microchannel, 13-micro mixer 16, 14-microchannel reactor, 15-first preheating microchannel, 16-constant temperature oil bath, 17-back pressure valve, 18-cooling tank, 19-oil-water separator, 20-second thermal oil heating furnace, 21-eighth ball valve, 22-ninth ball valve, 23-second high-temperature oil pump, 24-fifth ball valve, 25-sixth ball valve, 26-seventh ball valve, 27-product storage tank, 28-online GC, 29-second ball valve, 30-first thermal oil heating furnace, 31-first ball valve, 32-first high-temperature oil pump. DETAILED DESCRIPTION

[0035] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0036] The disclosed embodiment provides a method for synthesizing ethylhexylglycerol by continuous hydrolysis, wherein 2-ethylhexyl glycidyl ether and deionized water are used as raw materials, and ethylhexyl glycerol is synthesized by continuous hydrolysis under Lewis acid catalysis and without adding any solvent, in a microchannel reactor at relatively high temperature and pressure conditions.

[0037] Figure 1 A flow chart of a method for synthesizing ethylhexylglycerol by continuous hydrolysis provided in this embodiment. Figure 1 As shown, the method specifically comprises the following steps:

[0038] Step S1: adding deionized water and a catalyst into a premixing kettle according to a preset mass ratio, stirring evenly, and then pumping the mixture into a first raw material storage tank for preheating, and pumping 2-ethylhexyl glycidyl ether into a second raw material storage tank for preheating;

[0039] Preferably, in step S1, the catalyst is a Lewis acid catalyst, which includes any one or a combination of any two or more of zinc chloride, aluminum chloride, ferric chloride or copper chloride.

[0040] Preferably, in step S1, the preset mass ratio of the deionized water to the catalyst is 100:0.2-0.5; and the preheating temperatures in the first raw material storage tank and the second raw material storage tank are both 50-100°C.

[0041] Preferably, in step S1, the deionized water and the catalyst uniformly stirred in the premixing kettle are pumped into the first raw material storage tank by a first gear pump for preheating, and the 2-ethylhexyl glycidyl ether is pumped into the second raw material storage tank by a second gear pump for preheating.

[0042] Step S2: pumping the deionized water and catalyst obtained in step S1 into the first preheating microchannel through a first metering pump for secondary preheating, and pumping the 2-ethylhexyl glycidyl ether obtained in step S1 into the second preheating microchannel through a second metering pump for secondary preheating; wherein the deionized water in the first preheating microchannel and the 2-ethylhexyl glycidyl ether in the second preheating microchannel are pumped in according to a preset flow volume ratio;

[0043] Preferably, in step S2, the preset flow volume ratio of the deionized water in the first preheating microchannel and the 2-ethylhexyl glycidyl ether in the second preheating microchannel is 1.1-1.3:1; the temperature in the first preheating microchannel and the second preheating microchannel are both 150-250°C, and the pressure is both 0.5-4.0Mpa.

[0044] Preferably, in step S2, the first metering pump and the second metering pump are both plunger metering pumps.

[0045] Step S3: sending the deionized water and catalyst obtained in step S2, and the 2-ethylhexyl glycidyl ether into a micro mixer for mixing, and sending the mixed product into a microchannel reactor for a preset time to react to synthesize ethylhexyl glycerol, and after online analysis and detection of the synthesized ethylhexyl glycerol, sending it into a product storage tank to obtain a product mixed solution;

[0046] Preferably, in step S3, the mixed product is sent to the microchannel reactor and stays there for a preset time of 15-60 min, and the control temperatures of the microchannel reactor and the micromixer are both 150-250° C. and the pressures are both 0.5-4.0 MPa.

[0047] Step S4: cooling the product mixture obtained in step S3 to room temperature to separate the organic phase component, and distilling the organic phase component under vacuum conditions using a molecular distillation device to obtain an ethylhexylglycerol product.

[0048] Preferably, in step S4, the organic phase components are distilled in a molecular distillation device with a vacuum degree of 30-40 Pa, and the fraction at a temperature of 113-117° C. is collected as the target product, which is ethylhexylglycerol.

[0049] The present invention provides a method for synthesizing ethylhexylglycerol by continuous hydrolysis, which uses 2-ethylhexyl glycidyl ether and deionized water as raw materials, and continuously hydrolyzes ethylhexyl glycerol through a microchannel reactor under conditions of relatively high temperature and pressure under Lewis acid catalysis and without adding any solvent, so as to overcome the defects of synthesizing ethylhexyl glycerol in a traditional reaction flask (kettle), such as more by-products due to uneven heating of the reaction, difficulty in control, poor reaction selectivity, low product yield, complicated process and high cost, increased energy consumption due to recovery of organic solvents during the synthesis process, and environmental risks.

[0050] Compared with the prior art, the method for synthesizing ethylhexylglycerol by continuous hydrolysis disclosed in the present disclosure has the characteristics of short reaction cycle, high conversion rate and yield of target product, no solvent added in the reaction, avoiding the generation of by-products in the post-treatment process, reducing pollution to the environment, high product purity, low energy consumption, etc. Ethylhexylglycerol can be prepared by the method disclosed in the present disclosure, and a higher yield can be obtained, the product yield can reach more than 97%, the purity can reach more than 99.9%, the product appearance is a colorless transparent solution, no odor, and is better than similar products on the current market.

[0051] Figure 2 Schematic diagram of the structure of a microchannel reactor provided in an embodiment of the present disclosure. Figure 2 As shown, the microchannel reactor includes: a premixing kettle 1, a second raw material storage tank 4, a first raw material storage tank 6, a second filter 8, a first filter 10, a second plunger metering pump 9, a first plunger metering pump 11, a second preheating microchannel 12, a first preheating microchannel 15, a micro mixer 13, a microchannel reactor 14, a constant temperature oil bath 16, a back pressure valve 17, a cooling tank 18, an oil-water separator 19, a product storage tank 27, an online GC 28 and a first thermal oil heating furnace 30; wherein,

[0052] The first interface of the first thermal oil heating furnace 30 is connected to the second raw material storage tank 4 through a first pipeline, and the second interface of the first thermal oil heating furnace 30 is connected to the first raw material storage tank 6 through a second pipeline. The first pipeline is provided with a first ball valve 31, and the second pipeline is provided with a first high-temperature oil pump 32 and a second ball valve 29; the premixing kettle 1 is connected to the first raw material storage tank 6;

[0053] The second raw material storage tank 4 is connected to the inlet end of the second plunger metering pump 9 through a third pipeline, the first raw material storage tank 6 is connected to the inlet end of the first plunger metering pump 11 through a fourth pipeline, the third pipeline is provided with a third ball valve 5 and a second filter 8, and the fourth pipeline is provided with a fourth ball valve 7 and a first filter 10;

[0054] The outlet end of the second plunger metering pump 9 is connected to the inlet end of the second preheating microchannel 12 in the constant temperature oil bath 16, and the outlet end of the first plunger metering pump 11 is connected to the inlet end of the first preheating microchannel 15 in the constant temperature oil bath 16;

[0055] The outlet end of the second preheating microchannel 12 and the outlet end of the first preheating microchannel 15 are respectively connected to the inlet end of the micromixer 13, the outlet end of the micromixer 13 is connected to the inlet end of the microchannel reactor 14, the outlet end of the microchannel reactor 14 is connected to the back pressure valve 17 and then connected to the inlet end of the cooling tank 18, the outlet end of the cooling tank 18 is connected to the oil-water separator 19, the organic phase component separated from the oil-water separator 19 is analyzed by the online GC28 through the fifth pipeline, and then enters the product storage tank 27 through the sixth pipeline; wherein, the fifth pipeline is provided with a fifth ball valve 24 and a sixth ball valve 25, and the sixth pipeline is provided with a seventh ball valve 26;

[0056] The microchannel reactor 14 is used to implement the process flow of any of the above-mentioned methods for synthesizing ethylhexylglycerol by continuous hydrolysis.

[0057] Preferably, the micro mixer 13 is a stratified flow micro mixer; the diameter of the microchannel reactor 14 is 0.05-2 mm.

[0058] Preferably, the microchannel reactor 14 also includes a second thermal oil heating furnace 20, which is connected to the constant temperature oil bath 16 through a seventh pipeline and an eighth pipeline respectively, an eighth ball valve 21 is provided on the seventh pipeline, and a ninth ball valve 22 and a second high-temperature oil pump 23 are provided on the eighth pipeline.

[0059] The microchannel reactor provided in the embodiment of the present disclosure is a continuous flow tubular reactor with a characteristic size of 10-1000 microns manufactured by precision machining technology. It has a small channel size, good mass transfer and heat transfer performance, and is highly integrated, has high safety performance, is easy to accurately control the reaction process, has no obvious amplification effect, etc., which can realize the controllable reaction and limit the generation of by-products. Therefore, it is of great significance to use the microchannel reactor to implement the process flow in the method for continuously synthesizing ethylhexylglycerol in the embodiment of the present disclosure.

[0060] The method for synthesizing ethylhexylglycerol by continuous hydrolysis provided in the present disclosure will be described in detail with reference to specific examples below.

[0061] Example 1

[0062] A deionized water solution containing 0.2% aluminum chloride and 2-ethylhexyl glycidyl ether are preheated to 60°C in a first raw material storage tank and a second raw material storage tank, respectively. The two preheated raw materials enter the first preheating microchannel and the second preheating microchannel for secondary preheating at a flow volume ratio of 1.1:1, respectively. After preheating, they enter the micromixer for mixing and then enter the microchannel reactor for reaction. The diameter of the microchannel reactor is 0.5mm, the reaction temperature is 150°C, the back pressure is 0.5Mpa, and the residence reaction time is 15min to obtain crude ethylhexyl glycerol. Online GC analysis shows that the content of ethylhexyl glycerol is 57.3%. The crude ethylhexyl glycerol is distilled by a molecular distillation device at a vacuum pressure of 30-40Pa, and the fraction at a temperature of 113-117°C is collected as the target product. The target product is colorless and transparent liquid ethylhexyl glycerol. Gas chromatography analysis of the target product revealed that the purity of ethylhexylglycerol prepared by the method for synthesizing ethylhexylglycerol by continuous hydrolysis provided in the embodiment of the present disclosure was 99.92%, and the yield was 54.6%.

[0063] Example 2

[0064] The deionized water solution containing 0.1% aluminum chloride, 0.3% ferric chloride and 2-ethylhexyl glycidyl ether were preheated to 60°C in the first raw material storage tank and the second raw material storage tank, respectively, and the two preheated raw materials were respectively entered into the first preheating microchannel and the second preheating microchannel for secondary preheating according to the flow volume ratio of 1.1:1, and then entered into the micro mixer for mixing and then entered into the microchannel reactor for reaction, the diameter of the microchannel reactor was 0.2mm, the reaction temperature was 180°C, the back pressure was 1.0Mpa, and the residence reaction time was 20min, and the crude ethylhexyl glycerol was obtained, and the content of ethylhexyl glycerol was 72.5% according to the online GC analysis. The crude ethylhexyl glycerol was distilled by molecular distillation equipment at a vacuum pressure of 30-40Pa, and the fraction at a temperature of 113-117°C was collected as the target product, which was a colorless transparent liquid ethylhexyl glycerol. Gas chromatography analysis of the target product revealed that the purity of ethylhexylglycerol prepared by the method for synthesizing ethylhexylglycerol by continuous hydrolysis provided in the embodiment of the present disclosure was 99.97% and the yield was 69.7%.

[0065] Example 3

[0066] The deionized water solution containing 0.2% copper chloride, 0.2% zinc chloride and 2-ethylhexyl glycidyl ether were preheated to 80°C in the first raw material storage tank and the second raw material storage tank, respectively, and the two preheated raw materials were respectively introduced into the first preheating microchannel and the second preheating microchannel for secondary preheating according to the flow volume ratio of 1.2:1, and then introduced into the micro mixer for mixing and then introduced into the microchannel reactor for reaction, wherein the diameter of the microchannel reactor was 0.2mm, the reaction temperature was 230°C, the back pressure was 2.8Mpa, and the residence reaction time was 40min, and the crude ethylhexyl glycerol was obtained, and the content of the ethylhexyl glycerol was 99.5% according to the online GC analysis. The crude ethylhexyl glycerol was distilled by molecular distillation equipment at a vacuum pressure of 30-40Pa, and the fraction at a temperature of 113-117°C was collected as the target product, which was a colorless transparent liquid ethylhexyl glycerol. Gas chromatography analysis of the target product revealed that the purity of ethylhexylglycerol prepared by the method for synthesizing ethylhexylglycerol by continuous hydrolysis provided in the embodiment of the present disclosure was 99.95%, and the yield was 97.3%.

[0067] Example 4

[0068] The deionized water solution containing 0.5% zinc chloride and 2-ethylhexyl glycidyl ether are preheated to 90°C in the first raw material storage tank and the second raw material storage tank, respectively, and the two preheated raw materials are respectively introduced into the first preheating microchannel and the second preheating microchannel for secondary preheating according to the flow volume ratio of 1.3:1, and then introduced into the micro mixer for mixing and then introduced into the microchannel reactor for reaction, wherein the diameter of the microchannel reactor 14 is 1mm, the reaction temperature is 250°C, the back pressure is 4.0Mpa, and the residence reaction time is 60min, and the crude ethylhexyl glycerol is obtained, and the content of the ethylhexyl glycerol is 95.1% according to the online GC analysis. The crude ethylhexyl glycerol is distilled by a molecular distillation device at a vacuum degree of 30-40Pa, and the fraction at a temperature of 113-117°C is collected as the target product, which is a colorless transparent liquid ethylhexyl glycerol. Gas chromatography analysis of the target product revealed that the purity of ethylhexylglycerol prepared by the method for synthesizing ethylhexylglycerol by continuous hydrolysis provided in the embodiment of the present disclosure was 99.92% and the yield was 92.4%.

[0069] Figure 3 IR chart of ethylhexylglycerol prepared by the method for synthesizing ethylhexylglycerol by continuous hydrolysis method provided in an embodiment of the present disclosure.

[0070] Figure 4 1HNMR chart of ethylhexylglycerol prepared by the method for synthesizing ethylhexylglycerol by continuous hydrolysis provided in an embodiment of the present disclosure.

[0071] Figure 5 GC chart of ethylhexylglycerol prepared by the method for synthesizing ethylhexylglycerol by continuous hydrolysis provided in an embodiment of the present disclosure.

[0072] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the disclosure disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The description and examples are intended to be exemplary only, and the true scope and spirit of the present disclosure are indicated by the following claims.

Claims

1. A method for synthesizing ethylhexylglycerol by continuous hydrolysis, characterized in that: The method comprises: Step S1: adding deionized water and a catalyst into a premixing kettle according to a preset mass ratio, stirring evenly, and then pumping the mixture into a first raw material storage tank for preheating, and pumping 2-ethylhexyl glycidyl ether into a second raw material storage tank for preheating; Step S2: pumping the deionized water and catalyst obtained in step S1 into the first preheating microchannel through a first metering pump for secondary preheating, and pumping the 2-ethylhexyl glycidyl ether obtained in step S1 into the second preheating microchannel through a second metering pump for secondary preheating; wherein the deionized water in the first preheating microchannel and the 2-ethylhexyl glycidyl ether in the second preheating microchannel are pumped in according to a preset flow volume ratio; Step S3: sending the deionized water and catalyst obtained in step S2, and the 2-ethylhexyl glycidyl ether into a micro mixer for mixing, and sending the mixed product into a microchannel reactor for a preset time to react to synthesize ethylhexyl glycerol, and after online analysis and detection of the synthesized ethylhexyl glycerol, sending it into a product storage tank to obtain a product mixed solution; Step S4: cooling the product mixed solution obtained in step S3 to room temperature to separate the organic phase component, and distilling the organic phase component under vacuum conditions using a molecular distillation device to obtain an ethylhexylglycerol product.

2. The method for synthesizing ethylhexylglycerol by continuous hydrolysis according to claim 1, characterized in that: In step S1, the catalyst is a Lewis acid catalyst, which includes any one or a combination of any two or more of zinc chloride, aluminum chloride, ferric chloride or copper chloride.

3. The method for synthesizing ethylhexylglycerol by continuous hydrolysis according to claim 1, characterized in that: In step S1, the preset mass ratio of the deionized water to the catalyst is 100:0.2-0.5; the preheating temperature in the first raw material storage tank and the second raw material storage tank is 50-100°C.

4. The method for synthesizing ethylhexylglycerol by continuous hydrolysis according to claim 1, characterized in that: In step S2, the preset flow volume ratio of the deionized water in the first preheating microchannel and the 2-ethylhexyl glycidyl ether in the second preheating microchannel is 1.1-1.3:1; the temperature in the first preheating microchannel and the second preheating microchannel are both 150-250°C, and the pressure is both 0.5-4.0Mpa.

5. The method for synthesizing ethylhexylglycerol by continuous hydrolysis according to claim 1, characterized in that: In step S3, the mixed product is sent to a microchannel reactor and stays there for a preset time of 15-60 min. The control temperatures of the microchannel reactor and the micromixer are both 150-250° C. and the pressures are both 0.5-4.0 MPa.

6. The method for synthesizing ethylhexylglycerol by continuous hydrolysis according to claim 1, characterized in that: In step S4, the organic phase components are distilled in a molecular distillation device with a vacuum degree of 30-40 Pa, and the fraction at a temperature of 113-117° C. is collected as the target product, which is ethylhexylglycerol.

7. The method for synthesizing ethylhexylglycerol by continuous hydrolysis according to claim 1, characterized in that: In step S1, the deionized water and the catalyst uniformly stirred in the premixing kettle are pumped into the first raw material storage tank through the first gear pump for preheating, and the 2-ethylhexyl glycidyl ether is pumped into the second raw material storage tank through the second gear pump for preheating.

8. The method for synthesizing ethylhexylglycerol by continuous hydrolysis according to claim 1, characterized in that: In step S2, the first metering pump and the second metering pump are both plunger metering pumps.

9. A microchannel reactor, characterized in that: The microchannel reactor comprises: a premixing kettle, a first raw material storage tank, a second raw material storage tank, a first filter, a second filter, a first plunger metering pump, a second plunger metering pump, a first preheating microchannel, a second preheating microchannel, a micromixer, a microchannel reactor, a constant temperature oil bath, a back pressure valve, a cooling tank, an oil-water separator, a product storage tank, an online GC and a first thermal oil heating furnace; wherein, The first interface of the first thermal oil heating furnace is connected to the first raw material storage tank through a first pipeline, and the second interface of the first thermal oil heating furnace is connected to the second raw material storage tank through a second pipeline. The first pipeline is provided with a first ball valve, and the second pipeline is provided with a first high-temperature oil pump and a second ball valve; the premixing kettle is connected to the second raw material storage tank; The first raw material storage tank is connected to the inlet end of the first plunger metering pump through a third pipeline, the second raw material storage tank is connected to the inlet end of the second plunger metering pump through a fourth pipeline, a third ball valve and a first filter are provided on the third pipeline, and a fourth ball valve and a second filter are provided on the fourth pipeline; The outlet end of the first plunger metering pump is connected to the inlet end of the first preheating microchannel in the constant temperature oil bath, and the outlet end of the second plunger metering pump is connected to the inlet end of the second preheating microchannel in the constant temperature oil bath; The outlet end of the first preheating microchannel and the outlet end of the second preheating microchannel are respectively connected to the inlet end of the micromixer, the outlet end of the micromixer is connected to the inlet end of the microchannel reactor, the outlet end of the microchannel reactor is connected to the back pressure valve and then connected to the inlet end of the cooling tank, the outlet end of the cooling tank is connected to the oil-water separator, the organic phase component separated from the oil-water separator passes through the fifth pipeline and is analyzed by the online GC, and then enters the product storage tank through the sixth pipeline; wherein the fifth pipeline is provided with a fifth ball valve and a sixth ball valve, and the sixth pipeline is provided with a seventh ball valve; The microchannel reactor is used to implement the process flow of the method for synthesizing ethylhexylglycerol by continuous hydrolysis as described in any one of claims 1 to 8.

10. A microchannel reactor according to claim 9, characterized in that: The microchannel reactor also includes a second thermal oil heating furnace, which is connected to the constant temperature oil bath through a seventh pipeline and an eighth pipeline respectively, an eighth ball valve is arranged on the seventh pipeline, and a ninth ball valve and a second high-temperature oil pump are arranged on the eighth pipeline.

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