阅读说明：本技术 一种连续合成对苯二酚二羟乙基醚的方法 (Method for continuously synthesizing hydroquinone dihydroxyethyl ether ) 是由 刘嵩 鄢冬茂 明卫星 边策 刘冰 王珂 贾志远 杨林涛 郭林 于 2020-12-23 设计创作，主要内容包括：本发明涉及有机合成领域,具体涉及一种微通道反应器连续合成对苯二酚二羟乙基醚的方法。以对苯二酚和环氧乙烷为原料,将催化剂加入对苯二酚稀释液中,将两原料通过计量平流泵控制同步输入至微通道反应系统中,调控对苯二酚和环氧乙烷的体积流量,反应液于微通道的反应单元发生中反应,即获得对苯二酚二羟乙基醚。本发明采用微通道连续工艺合成对苯二酚二羟乙基醚,可以实现快速升温,持液量小,安全性高,可以避免间歇工艺中初始浓度较高的环氧乙烷在快速升温中存在的易燃易爆风险。(The invention relates to the field of organic synthesis, in particular to a method for continuously synthesizing hydroquinone dihydroxyethyl ether by a microchannel reactor. Hydroquinone and ethylene oxide are used as raw materials, a catalyst is added into a hydroquinone diluent, the two raw materials are synchronously input into a microchannel reaction system through the control of a metering advection pump, the volume flow of the hydroquinone and the ethylene oxide is regulated and controlled, and reaction liquid reacts in a reaction unit of a microchannel to obtain the hydroquinone dihydroxyethyl ether. The method adopts a microchannel continuous process to synthesize the dihydroxyethyl hydroquinone ether, can realize rapid temperature rise, has small liquid holdup and high safety, and can avoid the flammable and explosive risks of the ethylene oxide with higher initial concentration in the intermittent process in the rapid temperature rise.)

1. A method for continuously synthesizing hydroquinone dihydroxyethyl ether is characterized in that hydroquinone and ethylene oxide are used as raw materials, a catalyst is added into hydroquinone diluent, the two raw materials are synchronously input into a microchannel reaction system through control of a metering advection pump, the volume flow rates of the hydroquinone and the ethylene oxide are regulated and controlled, and the reaction liquid reacts in a reaction unit of a microchannel to obtain the hydroquinone dihydroxyethyl ether.

2. The process for the continuous synthesis of hydroquinone bis hydroxyethyl ether according to claim 1, characterized in that said microchannel reaction unit comprises a microreaction mixer and a delay system, the reaction mixer and the delay system being connected in series by piping.

3. The process for the continuous synthesis of hydroquinone bis hydroxyethyl ether according to claim 2, characterized in that the micro-reaction mixer is a tubular reactor or a static mixer.

4. The process for the continuous synthesis of hydroquinone bis hydroxyethyl ether according to any of claims 1 to 3,

(1) preparation of hydroquinone and ethylene oxide aqueous solution: heating hydroquinone, dissolving in water, and adding a catalyst; dissolving ethylene oxide in water, and storing at low temperature for later use;

(2) reacting by using a microchannel reaction system: adjusting the pressure of a back pressure valve to 1-2MPa, starting a heating device of the microchannel reactor, raising the temperature to 80-150 ℃, synchronously inputting the hydroquinone and the ethylene oxide aqueous solution prepared in the step (1) into the microchannel reactor, adjusting and controlling the volume flow of the hydroquinone and the ethylene oxide, reacting the reaction liquid through a microchannel reaction unit, and neutralizing, crystallizing and decoloring after the reaction is finished to obtain the product.

5. The method for continuously synthesizing hydroquinone dihydroxyethyl ether according to claim 4, wherein the molar ratio of hydroquinone to ethylene oxide is 1:2.2-2.4, the mass concentration of the hydroquinone aqueous solution is 5-20%, and the mass concentration of the ethylene oxide aqueous solution is 5-20%.

6. The method for continuously synthesizing hydroquinone dihydroxyethyl ether according to claim 4, wherein the catalyst is one or two of sodium hydroxide and potassium hydroxide, and the mass of the catalyst added is 1-2% of that of hydroquinone.

7. The process for the continuous synthesis of hydroquinone bis hydroxyethyl ether according to claim 4, characterized in that the flow ratio of hydroquinone and ethylene oxide fed into the microreactor is from 1 to 10: 1.

Technical Field

The invention relates to the field of organic synthesis, in particular to a method for continuously synthesizing hydroquinone dihydroxyethyl ether by a microchannel reactor.

Background

Hydroquinone dihydroxyethyl ether (HQEE) is a symmetrical aromatic diol chain extender, has good compatibility with 4, 4' -diphenylmethane diisocyanate (MDI) prepolymer, can prepare high-resilience PU elastomer, and can obviously improve the tensile strength, tear strength, heat resistance, compression deformation, hardness and resilience of products compared with the aliphatic diol chain extender. The HQEE can be used for producing the casting polyurethane elastomer, so that the sensitivity of a formula system to equipment and process conditions is reduced, and the compatibility among components in the formula system is improved; HQEE is also used in the production of high performance thermoplastic polyurethane elastomers, and temperature resistant spandex and the like.

At present, the preparation method of the chain extender HQEE mainly comprises the following three methods:

(1) in the ethylene oxide route, alkaline substances are used as catalysts, and hydroquinone and ethylene oxide are used as raw materials to prepare HQEE under a certain pressure. The product yield of the route is high, the cost is low, but the ethylene oxide is flammable and explosive, and special safety protection measures are required;

(2) in the chlorohydrin route, hydroquinone and 2-chlorohydrin are used as raw materials under normal pressure, and qualified HQEE is obtained through a series of refining. The chloroethanol route has complex process operation, high raw material price and large amount of three wastes, and the route is eliminated by considering the raw material price and the environmental protection advantages;

(3) the ethylene carbonate route takes hydroquinone and ethylene carbonate as raw materials to prepare HQEE under certain pressure. CO production during the reaction₂In addition, the ethylene carbonate is more expensive than ethylene oxide, and the raw material cost and the operation cost are increased.

The HQEE product is mainly prepared at home and abroad by adopting an ethylene oxide route, and the reaction formula is as follows:

as can be seen from the reaction formula, the reaction is an electrophilic addition reaction in which ethylene oxide is ring-opened under base catalysis. Under the condition of base catalysis, the reaction is easy to generate side reaction to generate a first condensation product and a third condensation product. Meanwhile, the raw material ethylene oxide is a toxic carcinogen, is inflammable and explosive, has large heat release amount in the early reaction stage of preparing HQEE by the traditional batch kettle type process, and has large potential safety hazard in the temperature rise process of a large amount of ethylene oxide in the amplification production process.

The patent CN105523905A discloses a method for synthesizing hydroquinone dihydroxyethyl ether, which comprises dissolving hydroquinone and ethylene oxide as raw materials and ferrocene as a catalyst in an ether solvent, reacting at 145 ℃ under 0-0.4MPa for 8-10h, desolventizing for 6-9h, distilling for 8h, and recovering to obtain the final product. The method has high yield and good product color, but the process reaction rate is low, the operation is complex, the whole time consumption is long, the cost of the used catalyst is higher than that of an alkali catalyst, and meanwhile, the time consumption of the ethylene oxide in a dropwise adding mode is longer, so that the process amplification is not facilitated.

Therefore, the method for synthesizing the HQEE has important significance in high safety and simple process.

Disclosure of Invention

The invention provides a method for continuously synthesizing hydroquinone dihydroxyethyl ether by a microchannel reactor aiming at the problems.

In order to achieve the purpose, the invention adopts the technical scheme that:

a method for continuously synthesizing hydroquinone dihydroxyethyl ether uses hydroquinone and ethylene oxide as raw materials, adds a catalyst into a hydroquinone diluent, controls and synchronously inputs the two raw materials into a microchannel reaction system through a metering advection pump, regulates and controls the volume flow of the hydroquinone and the ethylene oxide, and the reaction liquid reacts in a reaction unit of a microchannel to obtain the hydroquinone dihydroxyethyl ether.

The microchannel reaction unit comprises a micro-reaction mixer and a time delay system, and the reaction mixer and the time delay system are sequentially connected in series through pipelines.

The micro-reaction mixer is a tubular reactor or a static mixer,

further, the following steps are carried out:

(1) preparation of hydroquinone and ethylene oxide aqueous solution: heating hydroquinone, dissolving in water, and adding a catalyst; dissolving ethylene oxide in water, and storing at low temperature for later use;

(2) reacting by using a microchannel reaction system: adjusting the pressure of a back pressure valve to 1-2MPa (preferably 1.5-1.8MPa), starting a heating device of the microchannel reactor, heating to 80-150 ℃ (preferably 90-100 ℃), synchronously inputting the hydroquinone and the ethylene oxide aqueous solution prepared in the step (1) into the microchannel reactor, regulating and controlling the volume flow of the hydroquinone and the ethylene oxide, reacting the reaction liquid through a microchannel reaction unit, and neutralizing, crystallizing and decoloring after the reaction is finished to obtain the product.

The molar ratio of hydroquinone to ethylene oxide is 1:2.0-2.4 (1: 2.1-2.2 is preferred), the mass concentration of hydroquinone aqueous solution is 5% -20% (7% -10 is preferred), and the mass concentration of ethylene oxide aqueous solution is 5% -20% (8% -14 is preferred).

The catalyst is one or two of sodium hydroxide and potassium hydroxide, and the adding mass of the catalyst is 1-2% of that of hydroquinone.

The flow ratio of hydroquinone to ethylene oxide input into the microreactor is 1-10: 1.

the reaction residence time (i.e., the residence time in the reactor and the extension time) is determined depending on the actual reaction conditions, and is generally 3 to 10 min.

Compared with the prior art, the invention has the beneficial effects that:

1. according to the invention, the hydroquinone dihydroxyethyl ether is synthesized by adopting a microchannel continuous process, so that the rapid temperature rise can be realized, the liquid holdup is small, the safety is high, and the flammable and explosive risks of the ethylene oxide with higher initial concentration in the intermittent process in the rapid temperature rise can be avoided;

2. the micro-reactor can realize the rapid micro-mixing of the reaction materials of hydroquinone and ethylene oxide, greatly improve the mass and heat transfer efficiency, and solve the problems of long reaction time, high heat release rate and the like of an intermittent process.

3. The invention adopts the microchannel continuous process, has short residence time, can realize the control of the reaction by controlling the length of the delay system, and simultaneously can reduce the molar ratio of ethylene oxide in the feeding compared with the batch process to achieve equivalent product yield.

Drawings

FIG. 1 is a process flow diagram of the present invention.

Wherein, 1 and 2 are a first metering advection pump and a second metering advection pump, 3 is a micro-reactor, 4 and 5 are a first delay reactor and a second delay reactor, 6 is a back pressure valve, 7, 8, 9 and 10 are a first temperature sensor, a second temperature sensor, 11 is a pressure gauge, and 12 and 13 are a first sampling valve and a second sampling valve.

Detailed Description

The invention is described in detail below with reference to the figures and the specific examples, without limiting the scope of protection of the invention. Unless otherwise specified, the experimental methods adopted by the invention are all conventional methods, and experimental equipment, materials, reagents and the like used in the experimental method can be obtained from commercial sources.

And analyzing the reaction result by adopting a Gas Chromatography (GC) area normalization percentage quantification method, and calculating the Conversion (Conversion) and the Selectivity (Selectivity), wherein the specific calculation formula is as follows, wherein A is a reactant, and B is a product.

Example 1

As can be seen in fig. 1:

(1) preparation of hydroquinone and ethylene oxide aqueous solution: adding 80g of hydroquinone into 950mL of water for dilution to obtain hydroquinone aqueous solution with the mass concentration of 8%, adding sodium hydroxide into the hydroquinone aqueous solution, wherein the adding amount of the sodium hydroxide is 2% of the mass of the hydroquinone, and heating for dissolving; adding 500mL of water into ethylene oxide for dilution to obtain an ethylene oxide water solution with the mass concentration of 12%, and storing at low temperature, wherein the molar ratio of hydroquinone to ethylene oxide is 1: 2.1; is prepared from

(2) Adjusting the pressure of a back pressure valve to be 1.2MPa, heating to 80 ℃, preheating a pipeline and a feed pump, synchronously and respectively inputting hydroquinone and ethylene oxide aqueous solution into a microchannel reactor through a first metering advection pump and a second metering advection pump, wherein the flow rate of the hydroquinone aqueous solution is 19mL/min, the flow rate of the ethylene oxide aqueous solution is 10mL/min, the reaction residence time is 4min, and neutralizing, crystallizing and decoloring after the reaction is finished to obtain the product. The neutralized reaction solution was subjected to gas chromatography (FID detector, DB-5 column).

Example 2

(1) Preparation of hydroquinone and ethylene oxide aqueous solution: adding 80g of hydroquinone into 550mL of water for dilution to obtain a hydroquinone aqueous solution with the mass concentration of 13%, adding sodium hydroxide into the hydroquinone aqueous solution, wherein the adding amount of the sodium hydroxide is 2% of the mass of the hydroquinone, and heating for dissolving; adding 450mL of water into ethylene oxide for dilution to obtain an ethylene oxide water solution with the mass concentration of 14%, and storing at low temperature, wherein the molar ratio of hydroquinone to ethylene oxide is 1: 2.3;

(2) adjusting the pressure of a back pressure valve to be 1.5MPa, heating to 100 ℃, preheating a pipeline and a feed pump, then synchronously inputting hydroquinone and ethylene oxide aqueous solution into a microchannel reactor, wherein the flow rate of the hydroquinone aqueous solution is 18mL/min, the flow rate of the ethylene oxide aqueous solution is 15mL/min, the reaction retention time is 3.5min, and after the reaction is finished, neutralizing, crystallizing and decoloring to obtain the product. The neutralized reaction solution was subjected to gas chromatography (FID detector, DB-5 column).

Example 3

(1) Preparation of hydroquinone and ethylene oxide aqueous solution: adding 80g of hydroquinone into 1300mL of water for dilution to obtain a hydroquinone aqueous solution with the mass concentration of 6%, adding sodium hydroxide into the hydroquinone aqueous solution, wherein the adding amount of the sodium hydroxide is 2% of the mass of the hydroquinone, and heating for dissolving; adding 600mL of water into ethylene oxide for dilution to obtain an ethylene oxide water solution with the mass concentration of 10%, and storing at low temperature, wherein the molar ratio of hydroquinone to ethylene oxide is 1: 2.2;

(2) adjusting the pressure of a back pressure valve to be 1.8MPa, heating to 120 ℃, preheating a pipeline and a feed pump, then synchronously inputting hydroquinone and ethylene oxide aqueous solution into a microchannel reactor, wherein the flow rate of the hydroquinone aqueous solution is 17mL/min, the flow rate of the ethylene oxide aqueous solution is 13mL/min, the reaction retention time is 4min, and after the reaction is finished, neutralizing, crystallizing and decoloring to obtain the product. The neutralized reaction solution was subjected to gas chromatography (FID detector, DB-5 column).

Example 4

(1) Preparation of hydroquinone and ethylene oxide aqueous solution: adding 80g of hydroquinone into 720mL of water for dilution to obtain a hydroquinone aqueous solution with the mass concentration of 10%, adding sodium hydroxide into the hydroquinone aqueous solution, wherein the adding amount of the sodium hydroxide is 1% of the mass of the hydroquinone, and heating for dissolving; adding 700mL of water into ethylene oxide for dilution to obtain an ethylene oxide water solution with the mass concentration of 10%, and storing at low temperature, wherein the molar ratio of hydroquinone to ethylene oxide is 1: 2.4;

(2) adjusting the pressure of a back pressure valve to be 2MPa, heating to 150 ℃, preheating a pipeline and a feed pump, then synchronously inputting hydroquinone and ethylene oxide aqueous solution into a microchannel reactor, wherein the flow rate of the hydroquinone aqueous solution is 15mL/min, the flow rate of the ethylene oxide aqueous solution is 15mL/min, the reaction retention time is 4min, and after the reaction is finished, neutralizing, crystallizing and decoloring to obtain the product. The neutralized reaction solution was subjected to gas chromatography (FID detector, DB-5 column).

Example 5

(1) Preparation of hydroquinone and ethylene oxide aqueous solution: adding 80g of hydroquinone into 1000mL of water for dilution to obtain a hydroquinone aqueous solution with the mass concentration of 7%, adding sodium hydroxide into the hydroquinone aqueous solution, wherein the adding amount of the sodium hydroxide is 2% of the mass of the hydroquinone, and heating for dissolving; adding 500mL of water into ethylene oxide for dilution to obtain an ethylene oxide water solution with the mass concentration of 12%, and storing at low temperature, wherein the molar ratio of hydroquinone to ethylene oxide is 1: 2.1;

(2) adjusting the pressure of a back pressure valve to be 1.5MPa, heating to 100 ℃, preheating a pipeline and a feed pump, then synchronously inputting hydroquinone and ethylene oxide aqueous solution into a microchannel reactor, wherein the flow rate of the hydroquinone aqueous solution is 14mL/min, the flow rate of the ethylene oxide aqueous solution is 7.5mL/min, the reaction retention time is 3min, and after the reaction is finished, neutralizing, crystallizing and decoloring to obtain the product. The neutralized reaction solution was subjected to gas chromatography (FID detector, DB-5 column).

Example 6

(1) Preparation of hydroquinone and ethylene oxide aqueous solution: adding 80g of hydroquinone into 1000mL of water for dilution to obtain a hydroquinone aqueous solution with the mass concentration of 7%, adding sodium hydroxide into the hydroquinone aqueous solution, wherein the adding amount of the sodium hydroxide is 2% of the mass of the hydroquinone, and heating for dissolving; adding 500mL of water into ethylene oxide for dilution to obtain an ethylene oxide water solution with the mass concentration of 12%, and storing at low temperature, wherein the molar ratio of hydroquinone to ethylene oxide is 1: 2.1;

(2) adjusting the pressure of a back pressure valve to be 1.5MPa, heating to 100 ℃, preheating a pipeline and a feed pump, then synchronously inputting hydroquinone and ethylene oxide aqueous solution into a microchannel reactor, wherein the flow rate of the hydroquinone aqueous solution is 14mL/min, the flow rate of the ethylene oxide aqueous solution is 7.5mL/min, the reaction retention time is 6min, and after the reaction is finished, neutralizing, crystallizing and decoloring to obtain the product. The neutralized reaction solution was subjected to gas chromatography (FID detector, DB-5 column).

Example 7

(1) Preparation of hydroquinone and ethylene oxide aqueous solution: adding 80g of hydroquinone into 1000mL of water for dilution to obtain a hydroquinone aqueous solution with the mass concentration of 7%, adding sodium hydroxide into the hydroquinone aqueous solution, wherein the adding amount of the sodium hydroxide is 2% of the mass of the hydroquinone, and heating for dissolving; adding 500mL of water into ethylene oxide for dilution to obtain an ethylene oxide water solution with the mass concentration of 12%, and storing at low temperature, wherein the molar ratio of hydroquinone to ethylene oxide is 1: 2.1;

(2) adjusting the pressure of a back pressure valve to be 1.5MPa, heating to 100 ℃, preheating a pipeline and a feed pump, then synchronously inputting hydroquinone and ethylene oxide aqueous solution into a microchannel reactor, wherein the flow rate of the hydroquinone aqueous solution is 9.5mL/min, the flow rate of the ethylene oxide aqueous solution is 5mL/min, the reaction retention time is 8.5min, and after the reaction is finished, neutralizing, crystallizing and decoloring to obtain the product. The neutralized reaction solution was subjected to gas chromatography (FID detector, DB-5 column).

Example 8

(1) Preparation of hydroquinone and ethylene oxide aqueous solution: adding 80g of hydroquinone into 1000mL of water for dilution to obtain a hydroquinone aqueous solution with the mass concentration of 7%, adding sodium hydroxide into the hydroquinone aqueous solution, wherein the adding amount of the sodium hydroxide is 2% of the mass of the hydroquinone, and heating for dissolving; adding 1000mL of water into ethylene oxide for dilution to obtain an ethylene oxide water solution with the mass concentration of 6%, and storing at low temperature, wherein the molar ratio of hydroquinone to ethylene oxide is 1: 2.1;

(2) adjusting the pressure of a back pressure valve to be 1.5MPa, heating to 100 ℃, preheating a pipeline and a feed pump, then synchronously inputting hydroquinone and ethylene oxide aqueous solution into a microchannel reactor, wherein the flow rate of the hydroquinone aqueous solution is 15mL/min, the flow rate of the ethylene oxide aqueous solution is 15mL/min, the reaction retention time is 4min, and after the reaction is finished, neutralizing, crystallizing and decoloring to obtain the product. The neutralized reaction solution was subjected to gas chromatography (FID detector, DB-5 column).

Comparative examples

Dissolving 5g of hydroquinone in 40g of water, adding 0.1g of sodium hydroxide catalyst, stirring for dissolving, adding 4.5g of ethylene oxide, installing equipment, replacing an autoclave with nitrogen, keeping the pressure in the autoclave at about 0.05MPa, starting stirring, heating to 80 ℃, controlling the temperature in the reaction process at 80-82 ℃, reacting for 6 hours, taking out reaction liquid, neutralizing by hydrochloric acid, cooling the material, crystallizing, separating out, filtering, washing and drying to obtain the product. And (4) detecting and analyzing the neutralized reaction liquid by gas chromatography.

The results of gas chromatography analysis of the products obtained in the above comparative example and each of examples 1 to 8 are shown in Table 1.

TABLE 1HQEE Experimental analysis results

As can be seen from the comparative examples and examples, the HQEE continuous experiment by using the microchannel reactor obviously shortens the time required by the reaction from 6h of the batch process to 6-8 min. The data in table 1 show that by adjusting the continuous process conditions, the reaction performance is superior to the batch process. Meanwhile, the continuous process has small liquid holdup and high safety, and can avoid the danger of flammability and explosiveness of a large amount of ethylene oxide in the temperature rise process in the intermittent process.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be able to cover the technical solutions and the inventive concepts of the present invention within the technical scope of the present invention.