WO2019179144A1

WO2019179144A1 - Method and system for preparing methyl acetoacetate or ethyl acetoacetate by using tubular continuous flow reactor

Info

Publication number: WO2019179144A1
Application number: PCT/CN2018/116097
Authority: WO
Inventors: 庆九; 俞新南; 朱小刚; 刘芳
Original assignee: 南通醋酸化工股份有限公司
Priority date: 2018-03-21
Filing date: 2018-11-19
Publication date: 2019-09-26

Abstract

The present invention relates to the field of chemical production, and relates to a method and system for preparing methyl acetoacetate or ethyl acetoacetate by using a tubular continuous flow reactor. In the method, methanol or ethanol and a catalyst are respectively injected into a catalyst mixing section; after the two are mixed, a diketene metering pump is started; then, the diketene and an alcohol solution are injected into a tubular continuous flow reactor; the reaction pressure is adjusted by means of a pressure regulating valve; after reaction, a crude ester is cooled by a condenser and then flows into a buffering tank; a low-boiling point substance in the crude ester is refluxed to a buffering tank by means of the condenser; a non-condensable gas is emptied; the crude ester in the buffering tank is injected into a rectification column by means of the metering pump; the crude ester is then subjected to rectification to obtain a product of methyl acetoacetate or ethyl acetoacetate. Compared with a traditional intermittent process, the reaction retention time is greatly shortened, thereby reducing the generation of side reactions, increasing the product yield and content, and reducing the difficulty of rectification separation, reducing production costs, and greatly reducing the safety risks of production.

Description

Method and system for preparing methyl acetoacetate or ethyl acetoacetate by using tubular continuous flow reactor

Technical field

The invention belongs to the field of chemical production, and particularly relates to a method and a system for preparing methyl acetoacetate or ethyl acetoacetate by using a tubular continuous flow reactor.

Background technique

Methyl acetoacetate, alias: methyl butyrate; methyl acetoacetate; English name: Methyl acetoacetate; appearance properties: colorless liquid, with special odor; solubility: soluble in water; molecular formula: C5H8O3; molecular weight: 116.12 Melting point (°C): -28°C; density (g/ml, 25/4°C): 1.077. Methyl acetoacetate is mainly used in the pharmaceutical industry. It is a fungicide of carbendazim, dipyridamole, pyrethenol, insecticide diazinon, fly phos, pyrimidine oxyphosphate, herbicide imidazolium, rodenticide An intermediate such as ether or warfarin. It can also be used as a solvent for a cellulose ether and a mixed solvent of a cellulose resin, and is also used in organic synthesis such as pesticides, medicines, dyes, and polymer stabilizers.

Ethyl acetoacetate, alias: ethyl acetoacetate; ethyl ethyl butyrate; triethyl; ethyl 3-oxobutanoate; English name: Acetoacetic ester; Ethyl acetoacetate; Appearance: colorless or yellowish transparent liquid, Ether-like and apple-like aroma; Solubility: Soluble in water, miscible in most organic solvents; Molecular formula: C ₆ H ₁₀ O ₃ ; Molecular weight: 130.12; Melting point (°C): -45°C; Density (g /ml, 25/4 ° C): 1.0282. Function and use: It is widely used to prepare fruit and wine types (rum, whisky, etc.) such as strawberry, apple, apricot, cherry and peach. The pharmaceutical industry is used to manufacture aminopyrines, vitamin B, and the like. The dye industry is used as a raw material for synthetic dyes and for dyeing film substrates. The coatings industry is used to make clear paints and dilute solvents for paints. The organic industry is used as a solvent and as a material for the synthesis of organic compounds.

Prior art synthesis process:

The traditional methyl acetoacetate preparation process adopts a batch reactor reaction. First, the methanol and the catalyst are mixed, and then the temperature is raised to methanol reflux, and then the diketene is added dropwise according to a certain ratio, and the dropping time is 3-4 h. After the dropwise addition, the reaction liquid is heated to the temperature. 100-110 ° C, heat preservation 0.5 ~ 1h, after the crude ester is cooled, it is subjected to vacuum distillation to obtain a finished methyl acetoacetate product. Due to the long reaction time in batch process, diketene is highly prone to self-polymerization at higher temperatures, the reaction yield is low and the selectivity is poor, and from the safety point of view, such process safety risks are large. Therefore, the present invention develops a continuous flow reaction process of methyl acetoacetate, adopts a tubular continuous flow reactor, has low space occupation rate, low production cost, has a spiral mixing part inside the reactor, and diketene and alcohol in the reactor The internal mixing can be fully mixed, the reaction residence time is short, the yield and content of methyl acetoacetate are high, and the continuous flow reaction is a flat flow reaction, the back mixing is small, and the safety factor of the process is high.

The publication number is CN105384631, and the name is a continuous process for producing methyl acetoacetate. The utility model discloses a continuous process for producing methyl acetoacetate, which separates the esterification kettle into a heat preservation chamber and a cooling chamber, and lays off the crude ester, and adds methanol and diketene dropwise in the cooling chamber to pressurize the cooling chamber, and the product passes through the overflow. The flow tube overflows to the thermal storage chamber, and diketene is added dropwise to the overflow port. After the holding chamber reaches a certain amount, the pump is pumped to the rectification column to obtain a product. Disadvantages of this process: 1) Double addition of diketene, the molar ratio of the reaction is difficult to accurately control; 2) After accumulating a certain amount of the holding chamber, the pump is discharged, which greatly prolongs the residence time of the material, which is a semi-continuous process. The product readily decomposes at higher temperatures, which reduces product yield.

The publication number is CN103864616A2) and is a method for preparing methyl acetoacetate. The invention discloses a method for preparing methyl acetoacetate, in particular, the diketene and methanol are continuously added from the raw material port, the extracting agent is continuously added from the extraction port, and the two materials are simultaneously added to the reaction extractive distillation column, and the total reflux reaction is carried out. A mixture of methyl acetoacetate and an extractant can be obtained, and methanol is topped out, and the product yield is 95%, and the content is 99.3%. The disadvantage of this process is that the reaction system introduces an extracting agent, which increases the difficulty of product separation, is difficult to operate, and increases the production cost, and the yield and content of the product are slightly lower.

The traditional ethyl acetoacetate preparation process adopts a batch tank reaction. First, the ethanol and the catalyst are mixed, and then the temperature is raised to reflux of ethanol, and then the diketene is added dropwise according to a certain ratio, and the dropping time is 3-4 hours. After the dropwise addition, the reaction liquid is heated to the temperature. 100-110 ° C, heat preservation 0.5 ~ 1h, the crude ester is cooled, and then subjected to negative pressure rectification, thereby obtaining a finished ethyl acetoacetate. Due to the long reaction time in batch process, diketene is highly prone to self-polymerization at higher temperatures, the reaction yield is low and the selectivity is poor, and from the safety point of view, such process safety risks are large. Therefore, the present invention develops a continuous flow reaction process of ethyl acetoacetate, adopts a tubular continuous flow reactor, has low space occupation rate, low production cost, has a spiral mixing part inside the reactor, and diketene and alcohol in the reactor The internal mixing can be fully mixed, the reaction residence time is short, the yield and content of ethyl acetoacetate are high, and the continuous flow reaction is a flat flow reaction, the back mixing is small, and the safety factor of the process is high.

The publication number is CN102557939A1, and the name is a method for preparing ethyl acetoacetate. The invention relates to a method for preparing ethyl acetoacetate, which comprises reacting vaporized ethanol continuously through a fixed bed reactor provided with a catalyst layer to form ethyl acetoacetate, and the reaction temperature is 200 ° C to 700 ° C. Disadvantages: The reaction temperature is too high, and the yield and content of the product are low.

"Study on the preparation of ethyl acetoacetate by solid acid catalysis", Chemical Technology, May 25, 2015, 4, 57-50. In this paper, ethyl acetoacetate (EAA) was synthesized from diketene using solid acid as catalyst. The effects of catalyst type, dosage and recyclability on the reaction results were investigated. The experimental results show that under the optimal reaction conditions A product having a yield of 91% or more and a purity of 95% or more can be obtained by using a solid acid as a catalyst. The disadvantages of this process are: higher catalyst costs and lower reaction yields and product content.

Summary of the invention

In order to solve the above problems, it is an object of the present invention to provide a method and system for preparing methyl acetoacetate or ethyl acetoacetate using a tubular continuous flow reactor.

The invention firstly studies a process for preparing methyl acetoacetate by using a tubular continuous flow reactor. After premixing methanol with a catalyst, the diketene is thoroughly mixed with the tubular reactor at a certain pressure and temperature. The continuous esterification reaction greatly shortens the reaction residence time compared with the conventional batch process, thereby reducing the generation of side reactions, increasing the product yield and content, thereby reducing the difficulty of distillation separation and reducing the production cost. And greatly reduce the safety risks of production.

The invention further studies a process for preparing ethyl acetoacetate by using a tubular continuous flow reactor. After premixing ethanol with a catalyst, the diketene is thoroughly mixed with the tubular reactor at a certain pressure and temperature. The continuous esterification reaction greatly shortens the reaction residence time compared with the conventional batch process, thereby reducing the generation of side reactions, increasing the product yield and content, thereby reducing the difficulty of distillation separation and reducing the production cost. And greatly reduce the safety risks of production.

The technical solution of the present invention is as follows:

A method for preparing methyl acetoacetate or ethyl acetoacetate by using a tubular continuous flow reactor, comprising: the following steps:

First, from the methanol or ethanol metering tank and the catalyst metering tank, respectively, methanol or ethanol and the catalyst are respectively driven into the catalyst mixing section by a metering pump, and after mixing, the double ketene metering pump is started, and then the diketene and the diketene are activated. The alcohol solution is driven into the tubular continuous flow reactor at a certain flow rate, the reaction temperature is 50-150 ° C, the reaction residence time is 0.5-60 min, the reaction pressure is adjusted by a pressure regulating valve, the reaction pressure is 0-1 MPa, and the crude ester is reacted after the reaction. The condenser is cooled to 30-65 ° C, and then flows into the buffer tank. The low-boiling substance in the crude ester is returned to the buffer tank through the condenser, and the non-condensable gas is emptied, and the crude ester in the buffer tank is driven into the distillation column through the metering pump. The crude ester is subjected to rectification to obtain a product of methyl acetoacetate or ethyl acetoacetate;

The molar ratio of the diketene to methanol or ethanol is: 1:1 to 1.4;

The amount of the catalyst is from 0.03% to 2% of the total mass of the reactant;

The catalyst is selected from one or more of propylamine, butylamine, diethylamine, triethylamine, diethylenetriamine, aniline, and diisopropylamine.

According to the invention, a method for preparing methyl acetoacetate or ethyl acetoacetate by using a tubular continuous flow reactor, wherein the content of methyl acetoacetate or ethyl acetoacetate obtained by the method is 99.7 to 99.9%. The product yield is 98.8-99.0%.

Further, the molar ratio of the diketene to methanol or ethanol is 1:1.0-1.

Further, the catalyst is used in an amount of from 0.05% to 1.5% by mass based on the total mass of the reactants.

Further, the catalyst is one or more selected from the group consisting of diethylamine, triethylamine, aniline, and diisopropylamine.

A method for preparing methyl acetoacetate or ethyl acetoacetate by using a tubular continuous flow reactor according to the present invention, wherein the internal mixing unit structure of the tubular continuous flow reactor is SV type, SK type, SX type One of the SH type and the SL type.

According to the present invention, a method for preparing methyl acetoacetate or ethyl acetoacetate by using a tubular continuous flow reactor, further, the reaction temperature ranges from 55 to 135 ° C; the residence time ranges from 6 to 45 minutes; and the reaction pressure range is 0.02 to 0.5 MPa; the cooling temperature of the crude ester ranges from 35 to 55 °C.

The invention also provides a system for preparing methyl acetoacetate or ethyl acetoacetate by using a tubular continuous flow reactor, the above method being applicable to the system,

The system comprises a methanol or ethanol metering tank, and the methanol or ethanol metering tank and the catalyst metering tank are both connected to the inlet of the catalyst mixing section, and a methanol or ethanol metering pump is arranged between the methanol or ethanol metering tank and the catalyst mixing section. a catalyst metering pump is disposed between the catalyst metering tank and the catalyst mixing section; an outlet of the catalyst mixing section and a diketene metering tank are connected to the inlet of the tubular continuous flow reactor, and a double ketene metering pump is disposed between the diketene metering tank and the reaction section. The outlet of the tubular continuous flow reactor is connected in turn to a pressure regulating valve, a crude ester condenser, a crude ester buffer tank, and a crude ester pump; a condenser is disposed above the crude ester buffer tank.

Detailed description of the invention:

A method for preparing methyl acetoacetate using a tubular continuous flow reactor comprises the following steps:

Firstly, from the methanol metering tank and the catalyst metering tank, respectively, methanol and the catalyst are respectively driven into the catalyst mixing section by a metering pump, and after mixing, the double ketene metering pump is started, and then the diketene and the alcohol solution are fixed. The flow rate is driven into the tubular continuous flow reactor, the reaction temperature is 50-150 ° C, the reaction residence time is 0.5-60 min, the reaction pressure is adjusted by the pressure regulating valve, the reaction pressure is 0-1 MPa, and the crude ester is cooled by the condenser after the reaction. 30 to 65 ° C, and then flow into the buffer tank, the low boiler in the crude ester is returned to the buffer tank through the condenser, and the non-condensable gas is emptied. The crude ester in the buffer tank is driven into the rectification column by the metering pump, and the crude ester is passed through. After distillation, the product methyl acetoacetate is obtained;

The molar ratio of the diketene to methanol is: 1:1 to 1.4;

According to the invention, a method for preparing methyl acetoacetate by using a tubular continuous flow reactor, wherein the product obtained by the method has a methyl acetoacetate content of 99.7 to 99.9%, and a product yield of 98.8 to 99.0%.

Further, the molar ratio of the diketene to methanol is 1:1.0-1.

A method for preparing methyl acetoacetate by using a tubular continuous flow reactor according to the present invention, wherein the internal mixing unit structure of the tubular continuous flow reactor is SV type, SK type, SX type, SH type and SL One of the types.

According to the present invention, a method for preparing methyl acetoacetate by using a tubular continuous flow reactor, further, the reaction temperature ranges from 55 to 135 ° C; the residence time ranges from 6 to 45 minutes; and the reaction pressure ranges from 0.02 to 0.5 MPa; The crude ester has a cooling temperature in the range of 35 to 55 °C.

The present invention also provides a system for preparing methyl acetoacetate using a tubular continuous flow reactor, wherein a method for preparing methyl acetoacetate using a tubular continuous flow reactor can be applied to the system.

The system comprises a methanol metering tank 1 , and the methanol metering tank 1 and the catalyst metering tank 6 are both connected to the inlet of the catalyst mixing section 7 , and a methanol metering pump 4 is arranged between the methanol metering tank 1 and the catalyst mixing section 7 . A catalyst metering pump 5 is disposed between the catalyst metering tank 6 and the catalyst mixing section 7; the outlet of the catalyst mixing section 7 and the diketene metering tank 2 are connected to the inlet of the tubular continuous flow reactor 8, in the double ketene metering tank 2 and the reaction section A double ketene metering pump 3 is disposed between 8; the outlet of the reaction section 8 is sequentially connected with a pressure regulating valve 9, a crude ester condenser 10, a crude ester buffer tank 12 and a crude ester pumping pump 13; and is disposed above the crude ester buffer tank 12 Condenser 11.

The invention mainly aims at the problem that the reaction time is too long, the safety risk is high, the product yield and the content are slightly lower in the preparation process of the existing methyl acetoacetate, and a process for preparing methyl acetoacetate by using a tubular continuous flow reactor is developed. The reaction system is shown in Figure 1. The reaction process is shown in Figure 2. The specific steps are as follows:

First, from the methanol metering tank 1 and the catalyst metering tank 6, through the metering pumps 4 and 5, methanol and the catalyst are respectively driven into the catalyst mixing section 7 at a certain ratio of flow rate, and after mixing, the double ketene metering pump 3 is started, and then The diketene and the alcohol solution are driven into the tubular continuous flow reactor 8 at a certain flow rate, the reaction temperature is 50 to 150 ° C, the reaction residence time is 0.5 to 60 min, the reaction pressure is adjusted by the pressure regulating valve 9, and the reaction pressure is 0 to 1 MPa, and the reaction is carried out. The latter crude ester is cooled to 30 to 65 ° C by the condenser 10, and then flows into the buffer tank 12, and the low boiler in the crude ester is returned to the buffer tank 12 through the condenser 11, and the non-condensable gas is evacuated, and the buffer tank 12 is coarse. The ester is driven into the rectification column by the metering pump 13, and after the crude ester is rectified, the content of the product is 99.7 to 99.9%, and the product yield is 98.8 to 99.0%.

1) The molar ratio of the diketene to methanol is: 1:1 to 1.4, preferably 1:1.01 to 1.2;

2) the amount of the catalyst is from 0.03% to 2%, preferably from 0.05% to 1.5%, based on the total mass of the reactant;

3) The catalyst is selected from one or more of propylamine, butylamine, diethylamine, triethylamine, diethylenetriamine, aniline, diisopropylamine, preferably diethylamine, triethylamine, aniline Diisopropylamine;

4) The internal mixing unit structure of the tubular reactor is one of SV type, SK type, SX type, SH type and SL type, wherein the SV type unit is a cylinder assembled by corrugated plates of a certain specification; SK The type unit is formed by welding the left and right twisted spiral pieces of a single hole; the SX type unit is composed of a plurality of X-shaped units by a crossed strip; the SH type unit is composed of two holes, and a spiral piece is placed in the hole. The orientation of the adjacent two-channel is 90°; the SL-shaped unit is formed by a crossed strip to form a single X-shaped unit;

5) Preferably, the reaction temperature ranges from 55 to 135 ° C; the residence time ranges from 6 to 45 minutes; the reaction pressure ranges from 0.02 to 0.5 MPa; and the crude ester has a cooling temperature in the range of from 35 to 55 ° C.

The tubular reactor of the invention is of the prior art, the internal mixing component structure is a static mixer, and the static mixer means that there is no moving component in the pipeline, only the stationary original component can be divided into sv type, SK type, etc. The structure can be queried by keywords.

The reaction system of the invention consists of 13 parts: 1 is a methanol metering tank, 2 is a double ketene metering tank, 3 is a double ketene metering pump, 4 is a methanol metering pump, 5 is a catalyst metering pump, 6 is a catalyst metering tank, and 7 is a catalyst mixing section. 8 is a tubular continuous flow reactor, 9 is a pressure regulating valve, 10 is a crude ester condenser, 11 is a through-air condenser, 12 is a crude ester buffer tank, and 13 is a crude ester pump.

The invention provides a method for preparing ethyl acetoacetate by using a tubular continuous flow reactor, which comprises the following steps:

Firstly, from the ethanol metering tank and the catalyst metering tank, the metering pump is used to drive the ethanol and the catalyst into the catalyst mixing section at a certain proportion of the flow rate. After mixing the two, the double ketene metering pump is started, and then the diketene and the alcohol solution are subjected to a certain flow rate. The tubular continuous flow reactor is driven, the reaction temperature is 50-150 ° C, the reaction residence time is 0.5-60 min, the reaction pressure is adjusted by a pressure regulating valve, the reaction pressure is 0-1 MPa, and the crude ester is cooled to 30 after the reaction by the condenser. ～65 ° C, and then flow into the buffer tank, the low boiler in the crude ester is returned to the buffer tank through the condenser, and the non-condensable gas is emptied, and the crude ester in the buffer tank is driven into the rectification tower through the metering pump, and the crude ester is refined. After distillation, the product ethyl acetoacetate is obtained;

The molar ratio of the diketene to ethanol is: 1:1 to 1.4;

According to the invention, a method for preparing ethyl acetoacetate by using a tubular continuous flow reactor, the content of ethyl acetoacetate is 99.7 to 99.9%, and the product yield is 98.8 to 99.0%.

According to the invention, a method for preparing ethyl acetoacetate by using a tubular continuous flow reactor, further, the molar ratio of the diketene to ethanol is 1:1.01 to 1.2.

According to the invention, a method for preparing ethyl acetoacetate by using a tubular continuous flow reactor, further, the amount of the catalyst is from 0.05% to 1.5% of the total mass of the reactant.

According to the invention, a method for preparing ethyl acetoacetate by using a tubular continuous flow reactor, further, the catalyst is selected from one or more of diethylamine, triethylamine, aniline and diisopropylamine. .

According to the invention, a method for preparing ethyl acetoacetate by using a tubular continuous flow reactor, the internal mixing unit structure of the tubular reactor is one of SV type, SK type, SX type, SH type and SL type. .

According to the present invention, a method for preparing ethyl acetoacetate by using a tubular continuous flow reactor, further, the reaction temperature ranges from 55 to 135 ° C; the residence time ranges from 5 to 45 minutes; and the reaction pressure ranges from 0.02 to 0.5 MPa; The crude ester has a cooling temperature in the range of 35 to 55 °C.

The invention also provides a system for preparing ethyl acetoacetate using a tubular continuous flow reactor, the above method being applicable to the system,

The system includes an ethanol metering tank 1 connected to the inlet of the catalyst mixing section 7 and an ethanol metering pump 4 between the metering tank 1 and the catalyst mixing section 7 A catalyst metering pump 5 is disposed between the catalyst metering tank 6 and the catalyst mixing section 7; the outlet of the catalyst mixing section 7 and the diketene metering tank 2 are connected to the inlet of the tubular continuous flow reactor 8, in the double ketene metering tank 2 and the reaction section A double ketene metering pump 3 is disposed between 8; the outlet of the reaction section 8 is sequentially connected with a pressure regulating valve 9, a crude ester condenser 10, a crude ester buffer tank 12 and a crude ester pumping pump 13; and is disposed above the crude ester buffer tank 12 Condenser 11.

The invention mainly aims at the problem that the reaction time is too long, the safety risk is high, the product yield and the content are slightly lower in the preparation process of the existing ethyl acetoacetate, and a process for preparing ethyl acetoacetate by using a tubular continuous flow reactor is developed. The reaction system is shown in Figure 1. The reaction process is shown in Figure 3. The specific steps are as follows:

First, from the ethanol metering tank 1 and the catalyst metering tank 6, through the metering pumps 4 and 5, the ethanol and the catalyst are respectively driven into the catalyst mixing section 7 at a certain ratio of the flow rate, and after mixing, the double ketene metering pump 3 is started, and then The diketene and the alcohol solution are driven into the tubular continuous flow reactor 8 at a certain flow rate, the reaction temperature is 50 to 150 ° C, the reaction residence time is 0.5 to 60 min, the reaction pressure is adjusted by the pressure regulating valve 9, and the reaction pressure is 0 to 1 MPa, and the reaction is carried out. The latter crude ester is cooled to 30 to 65 ° C by the condenser 10, and then flows into the buffer tank 12, and the low boiler in the crude ester is returned to the buffer tank 12 through the condenser 11, and the non-condensable gas is evacuated, and the buffer tank 12 is coarse. The ester is driven into the rectification column by the metering pump 13, and after the crude ester is rectified, the content of the product is 99.7 to 99.9%, and the product yield is 98.8 to 99.0%.

1) The molar ratio of the diketene to ethanol is: 1:1 to 1.4, preferably 1:1.01 to 1.2;

5) Preferably, the reaction temperature ranges from 55 to 135 ° C; the residence time ranges from 5 to 45 minutes; the reaction pressure ranges from 0.02 to 0.5 MPa; and the crude ester has a cooling temperature in the range of from 35 to 55 ° C.

The reaction system of the invention consists of 13 parts: 1 is an ethanol metering tank, 2 is a dk metering tank, 3 is a dk metering pump, 4 is an ethanol metering pump, 5 is a catalyst metering pump, 6 is a catalyst metering tank, and 7 is a catalyst mixing section. 8 is the reaction section, 9 is the pressure regulating valve, 10 is the crude ester condenser, 11 is the transparent condenser, 12 is the crude ester buffer tank, and 13 is the crude ester pump.

Advantageous technical effects of the present invention:

1) Changing the batch process to a continuous flow process shortens the reaction time and reduces the generation of side reactions. The yield and content of methyl acetoacetate or ethyl acetoacetate are improved (the content of the product is 99.7% or more, and the product is collected. The rate is 98.8% or more);

2) From the mixing of the raw materials and the catalyst to the mixing reaction of the raw materials, and then to the crude ester rectification, the whole process is continuous operation, and the process operation is more simplified;

3) Compared with the batch reaction, the tubular continuous flow reactor is used to prepare methyl acetoacetate or ethyl acetoacetate, and the space occupation rate of the device is small, and the safety risk is low.

DRAWINGS

Figure 1 is a reaction system diagram for preparing methyl acetoacetate or ethyl acetoacetate using a tubular continuous flow reactor;

2 is a flow chart of a method for preparing methyl acetoacetate using a tubular continuous flow reactor;

Figure 3 is a flow diagram of a process for the preparation of ethyl acetoacetate using a tubular continuous flow reactor.

Among them: 1-methanol metering tank / ethanol metering tank, 2-dk metering tank, 3-dk metering pump, 4-methanol metering pump / ethanol metering pump, 5-catalyst metering pump, 6-catalyst metering tank, 7-catalyst mixing Section, 8-tube continuous flow reactor, 9-pressure regulating valve, 10-crude ester condenser, 11-air vent condenser, 12-crude ester buffer tank, 13-crude ester pump.

detailed description

The present invention will be further clarified by the following examples, and those skilled in the art should understand that the embodiments are only used for the examples and are not intended to limit the invention.

Example 1:

A method for preparing methyl acetoacetate by using a tubular continuous flow reactor: firstly, methanol and a catalyst are driven into a catalyst at a certain ratio from a methanol metering tank 1 and a catalyst metering tank 6 through

metering pumps

4 and 5, respectively. Mixing section 7, after mixing the two, start the double ketene metering pump 3, and then drive the diketene and the alcohol solution into the tubular continuous flow reactor 8 at a certain flow rate, and the internal mixing unit structure of the tubular reactor is SV type, the The molar ratio of diketene to methanol is 1:1.01, the catalyst is diethylamine, the amount of catalyst is 0.05% of the total mass of the reactants, the reaction temperature is 55 ° C, the reaction residence time is 45 min, and the reaction pressure is adjusted by the pressure regulating valve 9. The reaction pressure is 0.02 MPa. After the reaction, the crude ester is cooled to 35 ° C by the condenser 10, and then flows into the buffer tank 12. The low boiler in the crude ester is returned to the buffer tank 12 through the condenser 11, and the non-condensable gas is emptied. The crude ester in the buffer tank 12 was driven into the rectification column by the metering pump 13, and after the rectification of the crude ester, the content of the product was 99.7%, and the product yield was 98.8%.

Example 2:

metering pumps

4 and 5, respectively. Mixing section 7, after mixing the two, start the double ketene metering pump 3, and then drive the diketene and the alcohol solution into the tubular continuous flow reactor 8 at a certain flow rate, and the internal mixing unit structure of the tubular reactor is SX type, the The molar ratio of diketene to methanol is 1:1.04, the catalyst is triethylamine, the amount of catalyst is 0.1% of the total mass of the reactant, the reaction temperature is 105 ° C, the reaction residence time is 10 min, and the reaction pressure is adjusted by the pressure regulating valve 9. The reaction pressure is 0.3 MPa. After the reaction, the crude ester is cooled to 40 ° C by the condenser 10, and then flows into the buffer tank 12. The low boiler in the crude ester is returned to the buffer tank 12 through the condenser 11 and is not condensed. The crude ester in the buffer tank 12 was driven into the rectification column by the metering pump 13, and after the rectification of the crude ester, the content of the product was 99.8%, and the product yield was 98.9%.

Example 3:

metering pumps

4 and 5, respectively. Mixing section 7, after mixing the two, start the double ketene metering pump 3, and then drive the diketene and the alcohol solution into the tubular continuous flow reactor 8 at a certain flow rate, and the internal mixing unit structure of the tubular reactor is SH type, The molar ratio of diketene to methanol is 1:1.1, the catalyst is aniline, the amount of catalyst is 0.2% of the total mass of the reactant, the reaction temperature is 120 ° C, the reaction residence time is 20 min, and the reaction pressure is adjusted by the pressure regulating valve 9, the reaction The pressure is 0.2 MPa, and the crude ester after the reaction is cooled to 45 ° C by the condenser 10, and then flows into the buffer tank 12, and the low boiler in the crude ester is returned to the buffer tank 12 through the condenser 11, and the non-condensable gas is emptied, and the buffer tank The crude ester in 12 was driven into the rectification column by a metering pump 13, and after the rectification of the crude ester, the content of the product was 99.7%, and the product yield was 99.0%.

Example 4:

metering pumps

4 and 5, respectively. Mixing section 7, after mixing the two, start the double ketene metering pump 3, and then drive the diketene and the alcohol solution into the tubular continuous flow reactor 8 at a certain flow rate, and the internal mixing unit structure of the tubular reactor is SL type, the The molar ratio of diketene to methanol is 1:1.2, the catalyst is diisopropylamine, the amount of catalyst is 1% of the total mass of the reactants, the reaction temperature is 135 ° C, the reaction residence time is 6 min, and the pressure regulating valve 9 is adjusted. The reaction pressure is 0.5 MPa. After the reaction, the crude ester is cooled to 55 ° C by the condenser 10, and then flows into the buffer tank 12. The low boiler in the crude ester is returned to the buffer tank 12 through the condenser 11, and the non-condensable gas is discharged. Empty, the crude ester in the buffer tank 12 is driven into the rectification column by the metering pump 13, and after the rectification of the crude ester, the content of the product is 99.9%, and the product yield is 99.0%.

Example 4:

metering pumps

4 and 5, respectively. Mixing section 7, after mixing the two, start the double ketene metering pump 3, and then drive the diketene and the alcohol solution into the tubular continuous flow reactor 8 at a certain flow rate, and the internal mixing unit structure of the tubular reactor is SH type, The molar ratio of diketene to methanol is 1:1.2, and the catalyst is a mixture of triethylamine and diisopropylamine in a mixing ratio of m (triethylamine): m (diisopropylamine) = 1:1, catalyst The amount of the reaction is 0.5% of the total mass of the reactants, the reaction temperature is 115 ° C, the reaction residence time is 25 min, the reaction pressure is adjusted by the pressure regulating valve 9, the reaction pressure is 0.1 MPa, and the crude ester is cooled to 55 ° C by the condenser 10 after the reaction. And flowing into the buffer tank 12, the low boiler in the crude ester is returned to the buffer tank 12 through the condenser 11, and the non-condensable gas is emptied, and the crude ester in the buffer tank 12 is driven into the rectification tower by the metering pump 13, the crude ester. After rectification, the content of the product is 99.8 Product yield was 98.8%.

Example 5:

metering pumps

4 and 5, respectively. Mixing section 7, after mixing the two, start the double ketene metering pump 3, and then drive the diketene and the alcohol solution into the tubular continuous flow reactor 8 at a certain flow rate, and the internal mixing unit structure of the tubular reactor is SX type, the The molar ratio of diketene to methanol is 1:1.1, and the catalyst is a mixture of aniline, diethylamine and triethylamine in a mixing ratio of m (aniline): m (diethylamine): m (triethylamine) = 1: 1:1, the amount of the catalyst is 0.3% of the total mass of the reactant, the reaction temperature is 120 ° C, the reaction residence time is 22 min, the reaction pressure is adjusted by the pressure regulating valve 9, the reaction pressure is 0.3 MPa, and the crude ester is reacted through the condenser. 10 is cooled to 45 ° C, and then flows into the buffer tank 12, the low boiler in the crude ester is returned to the buffer tank 12 through the condenser 11, and the non-condensable gas is emptied, and the crude ester in the buffer tank 12 is driven into the fineness by the metering pump 13. Distillation column, crude ester after rectification, product containing The amount was 99.9%, and the product yield was 98.9%.

Example 6: A method for preparing ethyl acetoacetate using a tubular continuous flow reactor:

First, from the ethanol metering tank 1 and the catalyst metering tank 6, through the metering pumps 4 and 5, the ethanol and the catalyst are respectively driven into the catalyst mixing section 7 at a certain ratio of the flow rate, and after mixing, the double ketene metering pump 3 is started, and then The diketene and the alcohol solution are driven into the tubular continuous flow reactor 8 at a certain flow rate. The internal mixing unit structure of the tubular reactor is SV type, the molar ratio of the diketene to ethanol is 1:1.01, and the catalyst is diethylamine. The amount of the catalyst is 0.05% of the total mass of the reactants, the reaction temperature is 55 ° C, the reaction residence time is 45 min, the reaction pressure is adjusted by the pressure regulating valve 9, the reaction pressure is 0.02 MPa, and the crude ester is cooled by the condenser 10 after the reaction. At 35 ° C, it flows into the buffer tank 12, and the low boiler in the crude ester is returned to the buffer tank 12 through the condenser 11, and the non-condensable gas is emptied, and the crude ester in the buffer tank 12 is driven into the rectification column through the metering pump 13. After the crude ester was subjected to rectification, the content of the product was 99.7%, and the product yield was 98.9%.

Example 7: A method for preparing ethyl acetoacetate using a tubular continuous flow reactor:

First, from the ethanol metering tank 1 and the catalyst metering tank 6, through the metering pumps 4 and 5, the ethanol and the catalyst are respectively driven into the catalyst mixing section 7 at a certain ratio of the flow rate, and after mixing, the double ketene metering pump 3 is started, and then The diketene and the alcohol solution are driven into the tubular continuous flow reactor 8 at a certain flow rate. The internal mixing unit structure of the tubular reactor is SX type, the molar ratio of the diketene to ethanol is 1:1.05, and the catalyst is triethylamine. The amount of the catalyst is 0.12% of the total mass of the reactants, the reaction temperature is 106 ° C, the reaction residence time is 11 min, the reaction pressure is adjusted by the pressure regulating valve 9, the reaction pressure is 0.32 MPa, and the crude ester is cooled by the condenser 10 after the reaction. At 40 ° C, it flows into the buffer tank 12, and the low boiler in the crude ester is returned to the buffer tank 12 through the condenser 11, and the non-condensable gas is emptied, and the crude ester in the buffer tank 12 is driven into the rectification column by the metering pump 13. After the crude ester was subjected to rectification, the content of the product was 99.8%, and the product yield was 98.8%.

Example 8: A method for preparing ethyl acetoacetate using a tubular continuous flow reactor:

First, from the ethanol metering tank 1 and the catalyst metering tank 6, through the metering pumps 4 and 5, the ethanol and the catalyst are respectively driven into the catalyst mixing section 7 at a certain ratio of the flow rate, and after mixing, the double ketene metering pump 3 is started, and then The diketene and the alcohol solution are driven into the tubular continuous flow reactor 8 at a certain flow rate. The internal mixing unit structure of the tubular reactor is SH type, the molar ratio of the diketene to ethanol is 1:1.1, the catalyst is aniline, and the catalyst The amount of the reactants is 1% of the total mass of the reactants, the reaction temperature is 120 ° C, the reaction residence time is 20 min, the reaction pressure is adjusted by the pressure regulating valve 9, the reaction pressure is 0.2 MPa, and the crude ester is cooled to 45 ° C by the condenser 10 after the reaction. And flowing into the buffer tank 12, the low boiler in the crude ester is returned to the buffer tank 12 through the condenser 11, and the non-condensable gas is emptied, and the crude ester in the buffer tank 12 is driven into the rectification tower by the metering pump 13, the crude ester. After rectification, the content of the product was 99.7%, and the product yield was 99.0%.

Example 9: A method for preparing ethyl acetoacetate using a tubular continuous flow reactor:

First, from the ethanol metering tank 1 and the catalyst metering tank 6, through the metering pumps 4 and 5, the ethanol and the catalyst are respectively driven into the catalyst mixing section 7 at a certain ratio of the flow rate, and after mixing, the double ketene metering pump 3 is started, and then The diketene and the alcohol solution are driven into the tubular continuous flow reactor 8 at a certain flow rate. The internal mixing unit structure of the tubular reactor is SL type, the molar ratio of the diketene to ethanol is 1:1.2, and the catalyst is diisopropyl. The base amine, the amount of the catalyst is 1.5% of the total mass of the reactant, the reaction temperature is 135 ° C, the reaction residence time is 5 min, the reaction pressure is adjusted by the pressure regulating valve 9, the reaction pressure is 0.5 MPa, and the crude ester after the reaction is passed through the condenser 10 After cooling to 55 ° C, it flows into the buffer tank 12, and the low boiler in the crude ester is returned to the buffer tank 12 through the condenser 11, and the non-condensable gas is emptied, and the crude ester in the buffer tank 12 is driven into the distillation by the metering pump 13. After the distillation of the crude ester, the content of the product was 99.9%, and the product yield was 99.0%.

Example 10: A method for preparing ethyl acetoacetate using a tubular continuous flow reactor:

First, from the ethanol metering tank 1 and the catalyst metering tank 6, through the metering pumps 4 and 5, the ethanol and the catalyst are respectively driven into the catalyst mixing section 7 at a certain ratio of the flow rate, and after mixing, the double ketene metering pump 3 is started, and then The diketene and the alcohol solution are driven into the tubular continuous flow reactor 8 at a certain flow rate. The internal mixing unit structure of the tubular reactor is SH type, the molar ratio of the diketene to ethanol is 1:1.1, and the catalyst is triethylamine. a mixture with diisopropylamine, the mixing ratio is m (triethylamine): m (diisopropylamine) = 1:1, the amount of the catalyst is 0.5% of the total mass of the reactant, and the reaction temperature is 120 ° C. The reaction residence time is 20 min, the reaction pressure is adjusted by the pressure regulating valve 9, and the reaction pressure is 0.3 MPa. After the reaction, the crude ester is cooled to 45 ° C by the condenser 10, and then flows into the buffer tank 12, and the low boiler in the crude ester passes through the condenser. After 11 and refluxed to the buffer tank 12, the non-condensable gas is emptied, and the crude ester in the buffer tank 12 is driven into the rectification column by the metering pump 13. After the crude ester is rectified, the content of the product is 99.8%, and the product yield is 99.0. %.

Example 11: A method for preparing ethyl acetoacetate using a tubular continuous flow reactor:

First, from the ethanol metering tank 1 and the catalyst metering tank 6, through the metering pumps 4 and 5, the ethanol and the catalyst are respectively driven into the catalyst mixing section 7 at a certain ratio of the flow rate, and after mixing, the double ketene metering pump 3 is started, and then The diketene and the alcohol solution are driven into the tubular continuous flow reactor 8 at a certain flow rate. The internal mixing unit structure of the tubular reactor is SL type, the molar ratio of the diketene to ethanol is 1:1.2, and the catalyst is aniline, two. a mixture of ethylamine and triethylamine in a ratio of m (aniline): m (diethylamine): m (triethylamine) = 1:1:1, the amount of the catalyst is 0.3% of the total mass of the reactant, and the reaction The temperature is 135 ° C, the reaction residence time is 5 min, the reaction pressure is adjusted by the pressure regulating valve 9, the reaction pressure is 0.5 MPa, and the crude ester is cooled to 55 ° C by the condenser 10 after the reaction, and then flows into the buffer tank 12, and the crude ester is low. The boil is returned to the buffer tank 12 through the condenser 11, and the non-condensable gas is emptied. The crude ester in the buffer tank 12 is driven into the rectification column by the metering pump 13, and the content of the product after the crude ester is rectified is 99.9%. The product yield was 98.8%.

The invention has been disclosed in the above preferred embodiments, and is not intended to limit the invention, and the technical solutions obtained by equivalent substitution or equivalent transformation are all within the scope of the invention.

Claims

A method for preparing methyl acetoacetate or ethyl acetoacetate by using a tubular continuous flow reactor, comprising: the following steps:

First, from the methanol or ethanol metering tank and the catalyst metering tank, respectively, methanol or ethanol and the catalyst are respectively driven into the catalyst mixing section by a metering pump, and after mixing, the double ketene metering pump is started, and then the diketene and the diketene are activated. The alcohol solution is driven into the tubular continuous flow reactor at a certain flow rate, the reaction temperature is 50-150 ° C, the reaction residence time is 0.5-60 min, the reaction pressure is adjusted by a pressure regulating valve, the reaction pressure is 0-1 MPa, and the crude ester is reacted after the reaction. The condenser is cooled to 30-65 ° C, and then flows into the buffer tank. The low-boiling substance in the crude ester is returned to the buffer tank through the condenser, and the non-condensable gas is emptied, and the crude ester in the buffer tank is driven into the distillation column through the metering pump. The crude ester is subjected to rectification to obtain a product of methyl acetoacetate or ethyl acetoacetate;

The molar ratio of the diketene to methanol or ethanol is: 1:1 to 1.4;

The amount of the catalyst is from 0.03% to 2% of the total mass of the reactant;

The catalyst is selected from one or more of propylamine, butylamine, diethylamine, triethylamine, diethylenetriamine, aniline, and diisopropylamine.
The method for preparing methyl acetoacetate or ethyl acetoacetate by using a tubular continuous flow reactor according to claim 1, characterized in that the content of methyl acetoacetate or ethyl acetoacetate obtained by the method is It is 99.7 to 99.9%, and the product yield is 98.8 to 99.0%.
The method for preparing methyl acetoacetate or ethyl acetoacetate by using a tubular continuous flow reactor according to claim 1, wherein the molar ratio of the diketene to methanol or ethanol is 1:1.01~ 1.2.
A method for preparing methyl acetoacetate or ethyl acetoacetate using a tubular continuous flow reactor according to claim 1, wherein the catalyst is used in an amount of from 0.05% to 1.5% by mass based on the total mass of the reactants.
The method for preparing methyl acetoacetate or ethyl acetoacetate by using a tubular continuous flow reactor according to claim 1, wherein the catalyst is selected from the group consisting of diethylamine, triethylamine, aniline and diisopropyl ester. One or more of the amines.
The method for preparing methyl acetoacetate or ethyl acetoacetate by using a tubular continuous flow reactor according to claim 1, wherein the internal mixing unit structure of the tubular continuous flow reactor is SV type, One of the SK type, SX type, SH type and SL type.
The method for preparing methyl acetoacetate or ethyl acetoacetate by using a tubular continuous flow reactor according to claim 1, wherein the reaction temperature ranges from 55 to 135 ° C; the residence time ranges from 6 to 45 minutes; The pressure range is 0.02 to 0.5 MPa; the cooling temperature of the crude ester ranges from 35 to 55 °C.
A system for preparing methyl acetoacetate or ethyl acetoacetate using a tubular continuous flow reactor, the method according to any one of claims 1 to 7 being applicable to the system, characterized in that:

The system comprises a methanol or ethanol metering tank, and the methanol or ethanol metering tank and the catalyst metering tank are both connected to the inlet of the catalyst mixing section, and a methanol or ethanol metering pump is arranged between the methanol or ethanol metering tank and the catalyst mixing section. a catalyst metering pump is disposed between the catalyst metering tank and the catalyst mixing section; an outlet of the catalyst mixing section and a diketene metering tank are connected to the inlet of the tubular continuous flow reactor, and a double ketene metering pump is disposed between the diketene metering tank and the reaction section. The outlet of the tubular continuous flow reactor is connected in turn to a pressure regulating valve, a crude ester condenser, a crude ester buffer tank, and a crude ester pump; a condenser is disposed above the crude ester buffer tank.