Method for continuously synthesizing m-diethylaminophenol and equipment for implementing method

Abstract

The invention provides a method for continuously synthesizing m-diethylaminophenol and equipment for implementing the method. The method comprises the following steps: mixing and pulping m-hydroxyaniline and water to obtain pulping liquid; mixing the beating liquid with chloroethane and an ammonia water solution to obtain a first mixed solution, and reacting the first mixed solution in a tubular reactor to obtain a first reaction product; mixing the first reaction product with an ammonia water solution to obtain a second mixed solution, and placing the second mixed solution in a supergravity reactor for reaction to obtain a second reaction product; in percentage by mass, 70-90% of the second reaction product is returned to the supergravity reactor for continuous reaction; and carrying out post-treatment on the rest 10-30% of the second reaction product to obtain the m-diethylaminophenol. The method for continuously synthesizing m-diethylaminophenol is mild in reaction and relatively simple in reaction process, and the product is relatively high in purity and yield.

Description

Technical Field

[0001] The invention relates to a method for continuously synthesizing m-diethylaminophenol and equipment for implementing the method, and belongs to the field of organic synthesis and dye intermediate synthesis. Background Art

[0002] The molecular formula of m-diethylaminophenol is C 10 H 15 NO, white orthorhombic crystal or rose red solid, melting point 78℃, boiling point 276-280℃, slightly soluble in water at room temperature, soluble in hot water, alcohol, ether and sodium hydroxide solution, insoluble in petroleum. m-Diethylaminophenol is an important fine chemical intermediate, mainly used in dyes, medicines, cosmetics and other fields, and is widely used in heat and pressure sensitive dyes. As a dye intermediate, it is mainly used in the field of dyes to synthesize rose essence, acid pink, basic rutin and other dyes.

[0003] The synthesis of m-diethylaminophenol is mainly carried out by iron powder reduction method, in which sodium m-nitrobenzene sulfonate is reduced to sodium m-aminobenzene sulfonate with iron powder, and then alkylated with ethyl chloride, alkali fusion, acid precipitation and other processes to obtain it. This preparation method has a long reaction cycle, many process flows and low production efficiency; the alkali fusion process at high temperature easily oxidizes the product and affects the product quality; in addition, a large amount of iron powder is consumed in the reduction process, iron mud is generated, and the generation of wastewater, waste acid and waste alkali will increase the treatment cost.

[0004] The patent with publication number CN 109896967 A discloses a method for preparing m-diethylaminophenol, wherein m-dinitrobenzene and benzyl alcohol are used as raw materials, and 1-benzyloxy-3-nitrobenzene is reacted in an organic solvent containing alkaline inorganic salts, and the alkaline inorganic salts are removed from the reaction solution, and after the pH is adjusted to acidic by adding acid, a catalyst is used to catalyze the reaction with acetaldehyde in a hydrogen environment, and 1-benzyloxy-3-nitrobenzene and acetaldehyde are debenzylated by reductive amination and catalytic hydrogenation to generate m-diethylaminophenol. The method is simple, has mild conditions, and is of high purity, but the reaction time is still too long, the yield is low, and the cost of the H2 and catalysts such as Raney nickel and palladium carbon required for the synthesis is high, which poses a safety hazard.

[0005] The patent with publication number CN 114957018 A discloses a method for preparing m-hydroxy N,N-diethylaniline, which uses m-aminophenol and ethyl chloride as raw materials for alkylation reaction, and the reaction product is cooled, crystallized, and filtered to obtain a crude product after adjusting the base with ammonia water, and the crude product is distilled to obtain m-diethylaminophenol. The m-diethylaminophenol obtained by this method has high purity and yield, and the product quality is stable, but the post-treatment will produce more wastewater. At the same time, this method is an intermittent kettle reaction, and the reaction efficiency is low. The rapid reaction in the early stage of the reaction will cause the pH value of the product to fluctuate, increase the possibility of side reactions, and affect the product quality. In addition, the intermittent kettle reactor is large in size, which will increase the safety risk, and frequent discharge will also produce a large amount of waste gas.

[0006] The patent with publication number CN 103012164 A discloses a method for continuous production of m-diethylaminophenol in pipelines, wherein m-hydroxyphenol and ethyl chloride are dissolved in an ethanol solvent, pumped into a tubular reactor by a metering pump for reaction, the reaction product is collected and the solvent is removed, and an excess of alkali solution is added for washing to obtain a alkali-washed feed liquid; the alkali-washed feed liquid is extracted with an extracting liquid, the aqueous phase is acidified to be adjusted to neutrality, and then the m-diethylaminophenol product is obtained by vacuum distillation. This method has mild reaction conditions, stable product quality, high yield, and realizes the continuous synthesis of m-diethylaminophenol, but the alcohol solvent consumption is large, the solvent is not recycled, and the cost of the extracting liquid is high. Summary of the invention

[0007] Problem that the invention aims to solve

[0008] In view of the technical problems existing in the prior art, the present invention first provides a method for continuously synthesizing m-diethylaminophenol. The method for continuously synthesizing m-diethylaminophenol of the present invention has mild reaction, relatively simple reaction process, and the product has high purity and yield.

[0009] Furthermore, the present invention also provides a device for implementing the method for continuously synthesizing m-diethylaminophenol of the present invention, by combining a tubular reactor with an ultra-gravity reactor, m-diethylaminophenol is continuously synthesized, the reaction is mild, the product has a high purity and yield, and the post-treatment washing water is reused, thereby reducing the cost of wastewater treatment.

[0010] Solutions for solving problems

[0011] The present invention provides a method for continuously synthesizing m-diethylaminophenol, which comprises the following steps:

[0012] Mixing m-hydroxyaniline and water and beating to obtain a beating liquid;

[0013] reacting a first mixed solution obtained by mixing the pulping liquid with ethyl chloride and an ammonia solution in a tubular reactor to obtain a first reaction product;

[0014] placing a second mixed solution obtained by mixing the first reaction product with an aqueous ammonia solution in a supergravity reactor for reaction to obtain a second reaction product;

[0015] 70-90% of the second reaction product, by mass percentage, is returned to the supergravity reactor to continue the reaction; and the remaining 10-30% of the second reaction product is post-treated to obtain m-diethylaminophenol.

[0016] According to the method of the present invention, the mixing and beating is carried out in the presence of a protective gas, preferably, the protective gas is one or a combination of two or more of helium, neon, argon and nitrogen;

[0017] Preferably, in the pulping liquid, the mass concentration of m-hydroxyaniline is 20-40wt%;

[0018] Preferably, the beating temperature is 60-75°C.

[0019] According to the method of the present invention, the mass concentration of ammonia in the ammonia solution is 15-25wt%; and / or,

[0020] The temperature of the tubular reactor is controlled at 60-120° C., the pressure of the tubular reactor is controlled at 0.5-2.0 MPa, and the residence time of the first mixed solution in the tubular reactor is 0.5-5 h; and / or

[0021] In the reaction system, the molar ratio of the m-hydroxyaniline, the ethyl chloride and the ammonia is 1:(2.0-3.2):(2.0-3.2).

[0022] According to the method of the present invention, the temperature of the supergravity reactor and / or the circulation receiving tank is controlled to be 60-120° C., and the pressure is controlled to be 0.2-1.0 MPa; and / or,

[0023] The total residence time of the second mixed liquid and 70-90% of the second reaction product in the supergravity reactor and the circulation receiving tank is 3-9 hours.

[0024] According to the method of the present invention, the reaction in the high gravity reactor is carried out on a rotating packed bed, and preferably, the rotation speed of the rotor of the rotating packed bed is 1000-3500 r / min.

[0025] According to the method of the present invention, the post-treatment includes the steps of oil-water separation and / or washing; preferably, before the oil-water separation, the pH is adjusted to 5.5-7 using an aqueous ammonia solution.

[0026] The present invention provides a device for implementing the method for continuously synthesizing m-diethylaminophenol according to the present invention, which comprises a pulping unit, a reaction unit and a post-treatment unit connected in sequence; wherein the reaction unit comprises a tubular reactor and a supergravity reactor connected to each other.

[0027] According to the device of the present invention, the pulping unit comprises a raw material tank, and the outlet of the raw material tank is connected to the inlet of the tubular reactor;

[0028] Preferably, the inlet of the raw material tank is connected to a first metering tank.

[0029] According to the device of the present invention, the reaction unit further comprises a circulation receiving tank connected to the high gravity reactor, wherein the outlet of the high gravity reactor is connected to the inlet of the circulation receiving tank, and the outlet of the circulation receiving tank is connected to the inlet of the high gravity reactor;

[0030] Preferably, the reaction unit further comprises a second metering tank, and the second metering tank is connected to the tubular reactor and the supergravity reactor respectively;

[0031] Preferably, the reaction unit further comprises a pipeline mixer, and the pipeline mixer is connected to the raw material tank and the tubular reactor respectively.

[0032] According to the device of the present invention, the post-processing unit comprises a first oil-water separation tank and a washing tank connected to each other; the inlet of the first oil-water separation tank is connected to the outlet of the supergravity reactor, and the outlet of the first oil-water separation tank is connected to the inlet of the washing tank;

[0033] Preferably, a second oil-water separation tank is connected after the washing tank, and the second oil-water separation tank is also connected to the raw material tank.

[0034] Effects of the Invention

[0035] The method for continuously synthesizing m-diethylaminophenol of the present invention has mild reaction, relatively simple reaction process and high product purity and yield.

[0036] Furthermore, according to the advantages of the tubular reactor, the present invention arranges the tubular reactor at the front end of the supergravity reactor to improve the mass transfer and heat transfer effects in the early stage of the reaction. The materials entering the tubular reactor can be quickly and evenly mixed, and the generation of side reactions can be effectively avoided, thereby improving the conversion rate of the reaction. At the same time, the materials can be evenly dispersed in the reactor, and the degree of reaction can be better controlled.

[0037] Furthermore, in order to further improve the reaction speed in the middle and late stages of the alkylation reaction, the present invention uses the ultra-gravity reactor as an enhanced reaction device in the middle and late stages of the alkylation reaction based on its unique advantages to enhance the reaction mass transfer process. While improving the alkylation reaction rate and efficiency, it can also effectively inhibit the occurrence of side reactions.

[0038] Furthermore, the present invention combines a tubular reactor with a supergravity reactor, which can improve the alkylation reaction rate and efficiency, effectively avoid the generation of by-products, and improve product quality. At the same time, compared with traditional kettle reactors, the two equipments are relatively small in size, safe in operation, and can effectively reduce the risk of accidents.

[0039] Furthermore, the present invention combines a tubular reactor with a supergravity reactor to continuously synthesize m-diethylaminophenol, the reaction is mild, the product has high purity and yield, and the post-treatment washing water is reused, thereby reducing the cost of wastewater treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 The present invention discloses a simple reaction flow chart for continuously synthesizing m-diethylaminophenol.

[0041] Figure 2 The present invention is a schematic diagram of an apparatus for implementing a method for continuously synthesizing m-diethylaminophenol.

[0042] Description of Reference Numerals

[0043] 1: First metering tank; 2: Raw material tank; 3: Pipeline mixer; 4: Second metering tank;

[0044] 5: Tubular reactor; 6: Ultra-gravity reactor; 7: Circulation receiving tank; 8: Back pressure valve;

[0045] 9: first oil-water separation tank; 10: washing tank; 11: second oil-water separation tank;

[0046] a: first heat exchanger, b: second heat exchanger. DETAILED DESCRIPTION

[0047] Various exemplary embodiments, features and aspects of the present invention will be described in detail below. The word "exemplary" used here means "used as an example, embodiment or illustrative". Any embodiment described here as "exemplary" is not necessarily interpreted as being superior or better than other embodiments.

[0048] In addition, in order to better illustrate the present invention, numerous specific details are provided in the following specific embodiments. It should be understood by those skilled in the art that the present invention can be implemented without certain specific details. In other examples, methods, means, equipment and steps well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present invention.

[0049] Unless otherwise stated, the units used in this specification are all international standard units, and the numerical values ​​and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0050] In this specification, the word "may" means both performing a certain process and not performing a certain process.

[0051] In this specification, the references to "some specific / preferred embodiments", "other specific / preferred embodiments", "embodiments", etc., mean that the specific elements (e.g., features, structures, properties and / or characteristics) described in connection with the embodiments are included in at least one embodiment described herein, and may or may not exist in other embodiments. In addition, it should be understood that the elements may be combined in various embodiments in any suitable manner.

[0052] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints numerical values ​​A and B.

[0053] <First aspect>

[0054] A first aspect of the present invention provides a method for continuously synthesizing m-diethylaminophenol, which comprises the following steps:

[0055] Mixing m-hydroxyaniline and water and beating to obtain a beating liquid;

[0056] reacting a first mixed solution obtained by mixing the pulping liquid with ethyl chloride and an ammonia solution in a tubular reactor to obtain a first reaction product;

[0057] placing a second mixed solution obtained by mixing the first reaction product with an aqueous ammonia solution in a supergravity reactor for reaction to obtain a second reaction product;

[0058] 70-90% of the second reaction product, by mass percentage, is returned to the supergravity reactor to continue the reaction; and the remaining 10-30% of the second reaction product is post-treated to obtain m-diethylaminophenol.

[0059] In the method for continuously synthesizing m-diethylaminophenol of the present invention, in step (1), m-hydroxyaniline is used as a raw material and water or washing water is used as a solvent. At room temperature, m-hydroxyaniline is slightly soluble in water, and heating is required to dissolve the m-hydroxyaniline to obtain a m-hydroxyaniline slurry. Preferably, the stirring and mixing of m-hydroxyaniline and water or washing water is carried out in a raw material tank.

[0060] In some specific embodiments, the m-hydroxyaniline needs to be heated to dissolve during pulping. In order to prevent oxygen in the air from oxidizing the m-hydroxyaniline, the mixed pulping is carried out in the presence of a protective gas. Preferably, the protective gas is one or a combination of two or more of helium, neon, argon and nitrogen.

[0061] In some specific embodiments, in the beating liquid, the mass concentration of m-hydroxyaniline is 20-40wt%, for example: 22%, 25%, 28%, 30%, 32%, 35%, 38%, etc.; the mass concentration refers to the content of m-hydroxyaniline in the beating liquid. If the mass concentration of m-hydroxyaniline is too low, the effective content of hydroxyaniline in the beating liquid is small, thereby increasing the amount of water; if the mass concentration of m-hydroxyaniline is too high, the temperature for dissolving m-hydroxyaniline will also increase accordingly, which not only increases the additional energy consumption, but also causes the oxidation of m-hydroxyaniline. In the beating liquid of the present invention, the mass concentration of m-hydroxyaniline is preferably 24-30%.

[0062] In some specific embodiments, the beating temperature is 60-75°C, for example: 62°C, 65°C, 68°C, 70°C, 72°C, etc. In order to avoid oxidation of m-hydroxyaniline in a heated state, it is further preferred that the beating temperature is 65-72°C. The solubility of m-hydroxyaniline in water is affected by temperature. If the beating temperature is too low, the solubility of m-hydroxyaniline in water is small, the required mass concentration cannot be reached, and a homogeneous beating liquid cannot be formed. When entering the reaction unit later, it is very easy to cause blockage of the pipeline and the reactor. If the beating temperature is too high, the solubility of m-hydroxyaniline in water increases, but at the same time it will cause oxidation of m-hydroxyaniline, affecting the subsequent alkylation reaction and affecting the product quality.

[0063] In some specific embodiments, the mass concentration of ammonia in the ammonia solution is 15-25wt%, for example: 17%, 19%, 21%, 23%, etc. Further, in order to reduce the amount of product mother liquor wastewater, the mass concentration of ammonia is further preferably 22-25wt%.

[0064] In the present invention, the temperature of the tubular reactor is controlled to be 60-120°C, for example: 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, etc.; the pressure of the tubular reactor is controlled to be 0.5-2.0Mpa, for example: 0.7Mpa, 0.9Mpa, 1.1Mpa, 1, 3Mpa, 1.5Mpa, 1.7Mpa, 1.9Mpa, etc.; the residence time of the first mixed liquid in the tubular reactor is 0.5-4h, for example: 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, etc.

[0065] Temperature has a certain influence on the alkylation reaction. When the temperature is too low, the reaction rate in the early stage of the alkylation reaction will decrease, affecting the reaction progress. When the temperature is too high, the rate of the side reactions in the early stage of the alkylation reaction will accelerate, affecting the product quality. Therefore, in the present invention, the temperature of the tubular reactor is preferably controlled at 90-110°C, the pressure of the tubular reactor is preferably controlled at 0.8-1.5Mpa, and the residence time of the first mixed liquid in the tubular reactor is preferably 0.5-2h.

[0066] In the overall reaction system of the present invention, the molar ratio of the m-hydroxyaniline, the ethyl chloride and the ammonia is 1:(2.0-3.2):(2.0-3.2). Specifically, the molar ratio of the m-hydroxyaniline to the ethyl chloride entering the tubular reactor is 1:(2.0-3.2). If the amount of ethyl chloride added is too little, the alkylation reaction is not thorough; if the amount of ethyl chloride added is too much, the internal pressure of the reactor is too high, and there is a risk of accidents; in addition, too much ethyl chloride will also cause the generation of side reactions, so the molar ratio of the m-hydroxyaniline to the ethyl chloride is preferably 1:(2.5-3.0).

[0067] Specifically, in the present invention, the molar ratio of the m-hydroxyaniline to ammonia entering the tubular reactor is 1:(1.7-2.3). If the amount of ammonia water is too little, the pH of the system is too low, and the generated hydrochloric acid will react with the raw materials and products to form salts, affecting the alkylation reaction rate; if the amount of ammonia water is too much, ethyl chloride is easily hydrolyzed, resulting in increased raw material consumption. Therefore, the molar ratio of m-hydroxyaniline to ammonia is preferably 1:(1.7-2.2).

[0068] In some specific embodiments, the temperature of the supergravity reactor and / or the circulation receiving tank is controlled to be 60-120°C, for example: 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, etc.; the pressure is controlled to be 0.2-1.0Mpa, for example: 0.3Mpa, 0.5Mpa, 0.7Mpa, 0.9Mpa, etc. When the second mixed liquid enters the supergravity reactor for the alkylation reaction in the middle and late stages, if the temperature is too low, it will affect the reaction speed in the middle and late stages of the alkylation reaction, affect the reaction progress, and cause the reaction time to be too long; if the temperature is too high, it will accelerate the side reaction speed in the middle and late stages of the alkylation, affecting the product quality. In the present invention, the reaction temperature of the supergravity reactor is preferably 80-100°C, and the pressure is preferably 0.2-0.8Mpa.

[0069] Further, in the present invention, the total residence time of the second mixed liquor and 70-90% of the second reaction product in the supergravity reactor and the circulation receiving tank is 3-9 hours, for example: 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours, 8 hours, 8.5 hours, etc. Since the material enters the circulation receiving tank through the liquid outlet of the supergravity reactor after passing through the supergravity filler, the residence time of the material in the supergravity is very short, so the residence time in the supergravity reactor can be ignored. If the residence time is too short, the alkylation reaction is not complete; if the residence time is too long, it causes an increase in by-products. Preferably, the total residence time of the second mixed liquor and 70-90% of the second reaction product in the supergravity reactor and the circulation receiving tank is preferably 3-6 hours.

[0070] In some specific embodiments, the reaction in the ultragravity reactor is carried out on a rotating packed bed. Preferably, the rotation speed of the rotor of the rotating packed bed is 1000-3500 r / min, preferably 1500-2500 r / min, for example: 1200 r / min, 1500 r / min, 1800 r / min, 2000 r / min, 2200 r / min, 2500 r / min, 2800 r / min, 3000 r / min, 3200 r / min, etc.

[0071] In the present invention, the first reaction product is mixed with an ammonia solution and enters the supergravity reactor to continue the reaction, and the obtained second reaction product enters a circulation receiving tank, which is divided into two parts, wherein 70-90% of the second reaction product returns to the supergravity reactor to mix with the next batch of second mixed liquid and react, and the remaining 10-30% of the second reaction product enters the post-processing system. Therefore, the whole process of the present invention can be carried out continuously without interruption.

[0072] Furthermore, the content of the aqueous ammonia solution in the high-gravity reactor, calculated on the basis of the molar amount of m-hydroxyaniline, is in a molar ratio of m-hydroxyaniline to ammonia added to the high-gravity reactor of 1:(0.3-0.9), preferably 1:(0.3-0.8).

[0073] In some specific embodiments, the post-treatment includes the steps of oil-water separation and / or washing. After post-treatment, a meta-diethylaminophenol product, mother liquor water and washing water can be obtained. Among them, the mother liquor water enters the wastewater treatment system for resource utilization, and the washing water is used for raw material liquid preparation and reuse. The separation is carried out according to the different densities of the product, mother liquor water and washing water, including primary oil-water separation and secondary oil-water separation. The primary oil-water separation is mainly to separate the mother liquor water and the upper oil phase meta-diethylaminophenol crude product. The separated mother liquor water enters the wastewater treatment system for resource utilization; the separated upper oil phase meta-diethylaminophenol crude product enters the product washing tank, washes with hot water and enters the second oil-water separation tank. The upper washing water of the secondary oil-water separation is reused for the preparation of the pulping liquid in the raw material tank, and the lower layer discharges the oil phase meta-hydroxyaniline.

[0074] Preferably, before the oil-water separation, the pH is adjusted to 5.5-7 using an aqueous ammonia solution. The pH can be adjusted by the molar ratio of the m-hydroxyaniline to the aqueous ammonia solution. Too low or too high a pH will affect the oil-water separation of m-diethylaminophenol.

[0075] Furthermore, in the present invention, the separation and / or washing temperature may be 70-100°C, for example, 75°C, 80°C, 85°C, 90°C, 95°C, etc.

[0076] Through post-treatment, the remaining second reaction product can be separated and / or washed to obtain a liquid m-diethylaminophenol product, mother liquid water and washing water. The mother liquid water enters the wastewater treatment system for resource utilization, and the washing water returns to the raw material tank for raw material liquid preparation and reuse.

[0077] <Second Aspect>

[0078] like Figure 2 As shown, the second aspect of the present invention provides an apparatus for implementing the method for continuously synthesizing m-diethylaminophenol according to the first aspect of the present invention, which comprises a pulping unit, a reaction unit and a post-treatment unit connected in sequence; wherein the reaction unit comprises a tubular reactor 5 and an ultra-gravity reactor 6 connected to each other.

[0079] In some specific embodiments, the pulping unit comprises a raw material tank 2, and the outlet of the raw material tank 2 is connected to the inlet of the tubular reactor 5. In the present invention, the pulping unit is used to stir and mix m-hydroxyaniline and water or washing water and continuously pulp to obtain pulping liquid.

[0080] Furthermore, the inlet of the raw material tank 2 is connected to a first metering tank 1. By setting the first metering tank 1, the amount of water added can be controlled to obtain a pulping liquid with a desired mass concentration of m-hydroxyaniline.

[0081] In the present invention, the reaction unit is used to carry out an alkylation reaction of the pulping liquid with ethyl chloride. Preferably, the reaction unit also includes a second metering tank 4, which is connected to the tubular reactor 5 and the supergravity reactor 6 respectively; the present invention uses the second metering tank 4 to measure the amount of ammonia water so that the reaction can proceed normally. Furthermore, the discharge pipe of the second metering tank 4 is equipped with a first heat exchanger a, which is used to heat the ammonia water and heat it into the reaction unit. In the present invention, the first heat exchanger a is used to increase the feed temperature of the ammonia water, and the heat exchange medium is one or both of hot water and low-pressure steam.

[0082] In some specific embodiments, the reaction unit further comprises a pipeline mixer 3, which is connected to the raw material tank 2 and the tubular reactor 5, respectively, and is used to pre-mix the pulping liquid and the ammonia solution.

[0083] In some specific embodiments, the reaction unit further comprises a circulation receiving tank 7 connected to the supergravity reactor 6, wherein the outlet of the supergravity reactor 6 is connected to the inlet of the circulation receiving tank 7, and the outlet of the circulation receiving tank 7 is connected to the inlet of the supergravity reactor 6. The supergravity reactor 6, the circulation receiving tank 7 and the second heat exchanger b constitute a circulation system.

[0084] In some specific embodiments, the post-processing unit includes a first oil-water separation tank 9 and a washing tank 10 connected to each other; the inlet of the first oil-water separation tank 9 is connected to the outlet of the ultra-gravity reactor 6, and the outlet of the first oil-water separation tank 9 is connected to the inlet of the washing tank 10; preferably, a second oil-water separation tank 11 is also connected after the washing tank 10, and the second oil-water separation tank 11 is also connected to the raw material tank 2.

[0085] The post-processing unit of the present invention is used to separate and wash another part of the second reaction product separated by the circulation receiving tank 7, so as to obtain a liquid product of m-diethylaminophenol. In the present invention, the separation is carried out according to the different densities of m-diethylaminophenol, mother liquid water and washing water. Specifically, the post-processing unit includes a first oil-water separation tank 9, a washing tank 10 and a second oil-water separation tank 11. Among them, the temperature of the first oil-water separation tank 9, the second oil-water separation tank 10, the washing tank 11 and the washing hot water is controlled at 75-100°C. If the temperature is too low, the product will solidify and precipitate, which will cause problems such as pipeline blockage. If the temperature is too high, it will affect the product quality. Therefore, preferably, the temperature of the first oil-water separation tank 9, the second oil-water separation tank 10, the washing tank 10 and the washing hot water is controlled at 80-85°C.

[0086] In the present invention, in order to ensure that the crude product of m-diethylaminophenol entering the washing tank 10 is evenly distributed into the hot water, a distributor is installed on the top feed pipe of the product washing tank in the post-processing system to achieve a good washing effect. Preferably, the temperature of the first oil-water separation tank 9, the second oil-water separation tank 11, the washing tank 10 and the washing hot water can be controlled to 80-85°C.

[0087] In the present invention, the tanks, pipelines and other equipment in the system for continuously synthesizing m-diethylaminophenol are all provided with a heat-insulating medium, and the heat-insulating medium can be one or both of hot water and low-pressure steam.

[0088] In the present invention, the second heat exchanger b is used to take away the excess heat in the reactor, and the heat exchange medium is one or two of chilled water, chilled brine, and circulating cooling water.

[0089] Example

[0090] The embodiments of the present invention will be described in detail below in conjunction with the examples, but those skilled in the art will appreciate that the following examples are only used to illustrate the present invention and should not be considered to limit the scope of the present invention. If no specific conditions are specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be obtained commercially.

[0091] Example 1

[0092] The m-hydroxyaniline and water are put into a raw material tank, mixed and stirred under a nitrogen atmosphere to obtain a beating liquid, which is a m-hydroxyaniline aqueous solution with a mass concentration of 30wt%. The beating liquid is preheated to about 68°C, and the beating liquid and ammonia water with a mass concentration of about 23.5wt% are mixed in a pipeline mixer and then reacted with ethyl chloride into the first mixed liquid of a tubular reactor. The temperature of the tubular reactor is controlled at about 95°C, the pressure of the tubular reactor is controlled at about 1.1Mpa, and the residence time is 1h to obtain a first reaction product. In the tubular reactor, the molar ratio of m-hydroxyaniline to ammonia is 1:2.2.

[0093] After the first reaction product is mixed with ammonia water (the molar ratio of m-hydroxyaniline to ammonia is 1:0.4) having a mass concentration of about 23.5wt%, a second mixed solution is obtained, and the second mixed solution enters the supergravity reactor to continue to react to obtain a second reaction product. The second reaction product is separated by a circulation receiving tank, wherein, by mass percentage, 90% of the second reaction product returns to the supergravity reactor to mix with the next batch of the second mixed solution and continue to react, and 10% of the second reaction product is continuously extracted and enters the post-processing unit to ensure that the amount of material in the reaction system remains unchanged. Wherein, the temperature of the supergravity reactor and the circulation receiving tank is controlled at about 90°C, the pressure is controlled at about 0.6Mpa, the rotor speed of the supergravity reactor rotating bed packing is 2100r / min, and the total residence time of the second mixed solution and the second reaction product of 90% circulation in the supergravity reactor and the circulation receiving tank is 4 hours. In the overall reaction system, the material addition ratio of the pulping liquid, ammonia water and ethyl chloride is calculated based on the molar ratio of m-hydroxyaniline, ammonia and ethyl chloride, and the molar ratio of m-hydroxyaniline, ammonia and ethyl chloride is 1.0:2.6:2.8.

[0094] The second reaction product produced continuously is continuously transported to the first oil-water separation tank for oil-water separation. The pH is controlled at about 6 by an online pH meter using ammonia water with a mass concentration of about 23.5wt%. The residence time in the first oil-water separation tank is 2h, and then the upper oil phase continuously overflows into the washing tank, and the lower wastewater enters the wastewater treatment system for resource utilization; the overflow flow of the upper oil phase and the lower water phase is controlled by a regulating valve and a conductivity meter installed on the tank body of the first oil-water separation tank. Hot water is introduced into the washing tank, and after mixing and washing with the upper oil phase, the washing product continuously overflows to the second oil-water separation tank, and the residence time in the second oil-water separation tank is 0.5h. After the second oil-water separation tank, the upper washing water overflows and is reused for pulping liquid preparation, and the lower oil phase is discharged to obtain liquid m-diethylaminophenol. Among them, the temperature of the first oil-water separation tank, the washing tank, the second oil-water separation tank and the washing hot water is controlled at about 82°C.

[0095] The system continuously feeds and continuously extracts materials for 24 hours. According to high performance liquid chromatography detection, the average purity of the obtained liquid intermediate diethylaminophenol product is 98.0%. According to calculation, the average yield is 97.8%.

[0096] Example 2

[0097] The m-hydroxyaniline and water are allowed to enter the raw material tank, and the mixing and beating are carried out under a nitrogen atmosphere to obtain a beating liquid, which is a m-hydroxyaniline aqueous solution with a mass concentration of 30wt%. The beating liquid is preheated to about 68°C. The beating liquid and ammonia water with a mass concentration of about 23.5wt% are mixed in a pipeline mixer and reacted with ethyl chloride after entering a tubular reactor. The temperature of the tubular reactor is controlled at about 105°C, the pressure of the tubular reactor is controlled at about 0.8Mpa, and the residence time is 1.5h to obtain a first reaction product. In the tubular reactor, the molar ratio of m-hydroxyaniline to ammonia is 1:2.0. After the first reaction product is mixed with ammonia water with a mass concentration of about 23.5wt% (the molar ratio of m-hydroxyaniline to ammonia is 1:0.6), a second mixed solution is obtained, and the second mixed solution enters a supergravity reactor to continue the reaction to obtain a second reaction product. The second reaction product is separated by a circulation receiving tank. In terms of mass percentage, 80% of the second reaction product is returned to the supergravity reactor to mix with the next batch of the second mixed liquid and continue to react, and the remaining 20% ​​of the second reaction product is continuously extracted and enters the post-processing unit to ensure that the amount of material in the reaction system remains unchanged. Among them, the temperature of the supergravity reactor and the circulation receiving tank is controlled at about 100°C, the pressure is controlled at about 0.6Mpa, the rotor speed of the supergravity reactor rotating bed packing is 2500r / min, and the total residence time of the second mixed liquid and 80% of the circulating second reaction product in the supergravity reactor and the circulation receiving tank is 6 hours.

[0098] In the overall reaction system, the material addition ratio of the pulping liquid, ammonia water and ethyl chloride is calculated based on the molar ratio of m-hydroxyaniline, ammonia and ethyl chloride, and the molar ratio of m-hydroxyaniline, ammonia and ethyl chloride is 1.0:2.6:3.0.

[0099] The second reaction product continuously extracted by the circulation receiving tank is continuously transported to the first oil-water separation tank for oil-water separation. The pH is controlled at about 6 by an online pH meter using ammonia water with a mass concentration of about 23.5wt%. The residence time in the first oil-water separation tank is 1h, and then the upper oil phase continuously overflows into the washing tank, and the lower wastewater enters the wastewater treatment system for resource utilization; the overflow flow of the upper oil phase and the lower water phase is controlled by a regulating valve and a conductivity meter installed on the tank body of the first oil-water separation tank. Hot water is introduced into the washing tank, and after mixing and washing with the above-mentioned oil phase, the washing product continuously overflows to the second oil-water separation tank, and the residence time in the second oil-water separation tank is 0.5h. After the second oil-water separation, the upper washing water overflows and is reused for pulping liquid preparation, and the lower oil phase is discharged to obtain liquid m-diethylaminophenol. Among them, the temperature of the first oil-water separation tank, the washing tank, the second oil-water separation tank and the washing hot water is controlled at about 82°C.

[0100] The system continuously feeds and continuously extracts materials for 24 hours. According to high performance liquid chromatography detection, the average purity of the obtained liquid m-diethylaminophenol product is 97.4%. According to calculation, the average yield is 97.2%.

[0101] Example 3

[0102] The m-hydroxyaniline and water are allowed to enter a raw material tank, and mixed and stirred under a nitrogen atmosphere to obtain a beating liquid, which is an aqueous solution of m-hydroxyaniline with a mass concentration of 30wt%. The beating liquid is preheated to about 68°C, and the beating liquid and ammonia water with a mass concentration of about 23.5wt are allowed to enter a pipeline mixer and mixed with ethyl chloride to enter a tubular reactor for reaction. The temperature of the tubular reactor is controlled at about 90°C, the pressure of the tubular reactor is controlled at about 0.8Mpa, and the residence time is 0.5h to obtain a first reaction product. In the tubular reactor, the molar ratio of m-hydroxyaniline to ammonia is 1:1.8.

[0103] After mixing the first reaction product mixed solution with ammonia water (the molar ratio of m-hydroxyaniline to ammonia is 1:0.8) with a mass concentration of about 23.5wt%, a second mixed solution is obtained, and the second mixed solution enters the supergravity reactor to continue the reaction to obtain a second reaction product. The second reaction product is separated by a circulation receiving tank. In terms of mass percentage, 70% of the second reaction product enters the supergravity reactor again to mix with the next batch of the second mixed solution and continue to react, and the remaining 30% of the second reaction product is continuously extracted and enters the post-processing unit to ensure that the amount of material in the reaction system remains unchanged. Among them, the temperature of the supergravity reactor and the circulation receiving tank is controlled at about 95°C, the pressure is controlled at about 0.8Mpa, the rotor speed of the supergravity reactor rotating bed packing is 1500r / min, and the total residence time of the second mixed solution and 80% of the second reaction product in the supergravity reactor and the circulation receiving tank is 4h.

[0104] In the overall reaction system, the material addition ratio of the pulping liquid, ammonia water and ethyl chloride is calculated based on the molar ratio of m-hydroxyaniline, ammonia and ethyl chloride, and the molar ratio of m-hydroxyaniline, ammonia and ethyl chloride is 1.0:2.6:2.6.

[0105] The second reaction product produced continuously is continuously transported to the first oil-water separation tank for oil-water separation. The pH is controlled at about 6 by an online pH meter using ammonia water with a mass concentration of about 23.5wt%. The residence time in the first oil-water separation tank is 1h, and then the upper oil phase continuously overflows into the washing tank, and the lower wastewater enters the wastewater treatment system for resource utilization; the overflow flow of the upper oil phase and the lower water phase is controlled by a regulating valve and a conductivity meter on the tank body of the first oil-water separation tank. Hot water is introduced into the washing tank, and after mixing and washing with the upper oil phase, the washing product continuously overflows to the second oil-water separation tank, and the residence time in the second oil-water separation tank is 0.5h. After the second oil-water separation tank, the upper washing water overflows and is reused for pulping liquid preparation, and the lower oil phase is discharged to obtain liquid m-diethylaminophenol. Wherein, the temperature of the first oil-water separation tank, the washing tank, the second oil-water separation tank and the washing hot water is controlled at about 82°C.

[0106] The system continuously feeds and continuously extracts materials for 24 hours. According to high performance liquid chromatography detection, the average purity of the obtained liquid intermediate diethylaminophenol product is 95.3%. After calculation, the average yield is 94.0%.

[0107] It should be noted that, although the technical solution of the present invention is introduced with specific examples, those skilled in the art will appreciate that the present invention should not be limited thereto.

[0108] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A method for continuously synthesizing meta-diethylaminophenol, characterized in that, The following steps are involved: Mixing m-hydroxyaniline and water and beating to obtain a beating liquid; reacting a first mixed solution obtained by mixing the pulping liquid with ethyl chloride and an ammonia solution in a tubular reactor to obtain a first reaction product; placing a second mixed solution obtained by mixing the first reaction product with an aqueous ammonia solution in a supergravity reactor for reaction to obtain a second reaction product; 70-90% of the second reaction product, by mass percentage, is returned to the supergravity reactor to continue the reaction; the remaining 10-30% of the second reaction product is post-treated to obtain m-diethylaminophenol.

2. The method according to claim 1, characterized in that: The mixing and beating is carried out in the presence of a protective gas, preferably, the protective gas is one or a combination of two or more of helium, neon, argon and nitrogen; Preferably, in the pulping liquid, the mass concentration of m-hydroxyaniline is 20-40wt%; Preferably, the beating temperature is 60-75°C.

3. The method according to claim 1 or 2, characterized in that: The mass concentration of ammonia in the ammonia solution is 15-25wt%; and / or, The temperature of the tubular reactor is controlled at 60-120° C., the pressure of the tubular reactor is controlled at 0.5-2.0 MPa, and the residence time of the first mixed solution in the tubular reactor is 0.5-5 h; and / or In the reaction system, the molar ratio of the m-hydroxyaniline, the ethyl chloride and the ammonia is 1:(2.0-3.2):(2.0-3.2).

4. The method according to any one of claims 1 to 3, characterized in that: The temperature of the supergravity reactor and / or the circulation receiving tank is controlled at 60-120°C, and the pressure is controlled at 0.2-1.0Mpa; and / or, The total residence time of the second mixed liquid and 70-90% of the second reaction product in the supergravity reactor and the circulation receiving tank is 3-9 hours.

5. The method according to any one of claims 1 to 4, characterized in that: The reaction in the high gravity reactor is carried out on a rotating packed bed. Preferably, the rotation speed of the rotor of the rotating packed bed is 1000-3500 r / min.

6. The method according to any one of claims 1 to 5, characterized in that: The post-treatment includes the steps of oil-water separation and / or washing; preferably, before the oil-water separation, the pH is adjusted to 5.5-7 using an aqueous ammonia solution.

7. An apparatus for implementing the method for continuously synthesizing m-diethylaminophenol according to any one of claims 1 to 6, characterized in that: It comprises a beating unit, a reaction unit and a post-processing unit which are connected in sequence; wherein the reaction unit comprises a tubular reactor and a supergravity reactor which are connected.

8. The device according to claim 7, characterized in that The pulping unit comprises a raw material tank, the outlet of which is connected to the inlet of the tubular reactor; Preferably, the inlet of the raw material tank is connected to a first metering tank.

9. The device according to claim 7 or 8, characterized in that The reaction unit further comprises a circulation receiving tank connected to the high gravity reactor, wherein the outlet of the high gravity reactor is connected to the inlet of the circulation receiving tank, and the outlet of the circulation receiving tank is connected to the inlet of the high gravity reactor; Preferably, the reaction unit further comprises a second metering tank, and the second metering tank is connected to the tubular reactor and the supergravity reactor respectively; Preferably, the reaction unit further comprises a pipeline mixer, and the pipeline mixer is connected to the raw material tank and the tubular reactor respectively.

10. The device according to any one of claims 7 to 9, characterized in that: The post-processing unit comprises a first oil-water separation tank and a washing tank connected to each other; the inlet of the first oil-water separation tank is connected to the outlet of the supergravity reactor, and the outlet of the first oil-water separation tank is connected to the inlet of the washing tank; Preferably, a second oil-water separation tank is connected after the washing tank, and the second oil-water separation tank is also connected to the raw material tank.

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