阅读说明：本技术 一种间氨基苯甲酸乙酯的生产工艺 (Production process of ethyl m-aminobenzoate ) 是由 蒋敏 于 2020-12-28 设计创作，主要内容包括：本发明提供一种间氨基苯甲酸乙酯的生产工艺,将催化剂DCyPP·Pd(OAc)2、碳酸钾装入涓流床反应器中,加入3-氯苯胺和乙醇的混合物并通入一氧化碳,保持反应器内压力为0.1-0.2MPa,通过羰化酯化反应后,经过精馏塔纯化后得到摩尔产率为97％,纯度为98.5％以上的间氨基苯甲酸乙酯。本发明可实现连续生产间氨基苯甲酸乙酯,反应原料方便易得,工艺简单,反应条件温和,反应能耗低,反应过程无废酸产生,适合放大生产。(The invention provides a process for producing ethyl m-aminobenzoate, which comprises the steps of filling a catalyst DCyPP & Pd (OAc)2 and potassium carbonate into a trickle bed reactor, adding a mixture of 3-chloroaniline and ethanol, introducing carbon monoxide, keeping the pressure in the reactor at 0.1-0.2MPa, and purifying by a rectifying tower after carbonylation esterification to obtain the ethyl m-aminobenzoate with the molar yield of 97% and the purity of more than 98.5%. The method can realize continuous production of the ethyl m-aminobenzoate, has the advantages of convenient and easily obtained reaction raw materials, simple process, mild reaction conditions, low reaction energy consumption, no waste acid in the reaction process and suitability for large-scale production.)

1. The production process of ethyl m-aminobenzoate is characterized by comprising the following steps of:

pretreatment: the catalyst DCyPP & Pd (OAc)₂Uniformly mixing with potassium carbonate, and adding into a trickle bed reactor; mixing 3-chloroaniline and ethanol to obtain a reaction raw material mixture A, wherein the ethanol is used as a reactant and a solvent;

continuous production: adding the reaction raw material mixture A into a trickle bed reactor, introducing carbon monoxide, keeping the pressure in the reactor at 0.1-0.2MPa, and reacting at 80-100 ℃ for 1-1.5 h; obtaining a mixture B after the reaction is finished;

and (3) purification: pumping the mixture B into a rectifying tower, controlling the temperature of the tower kettle of the rectifying tower at 120 ℃, cooling a low-boiling-point compound through a condenser to obtain a distillate C, measuring the content of ethyl aminobenzoate in the distillate C, mixing the distillate C with the reaction raw material mixture A for further recycling when the content of ethyl m-aminobenzoate is less than 0.1%, and returning the distillate to the tower kettle of the rectifying tower when the content of ethyl m-aminobenzoate is more than 0.1%; and (4) measuring the purity of the residual liquid at the bottom of the tower, wherein the purity of the residual liquid reaches more than 98.5 percent and is the target product D-m-aminobenzoic acid ethyl ester, otherwise, further rectifying by a reboiler.

2. The process for producing ethyl m-aminobenzoate according to claim 1, characterized in that: catalyst DCyPP. Pd (OAc)₂Prepared by the following steps: dissolving 1, 3-bis (dicyclohexylphosphino) propanebis (tetrafluoroborate) (DCyPP) and palladium acetate in a molar ratio of 1:1 in acetonitrile, crystallizing at 25 ℃ for 24 hours, and drying to obtain a catalyst DCyPP. Pd (OAc)₂。

3. The process for producing ethyl m-aminobenzoate according to claim 1, characterized in that: in the pretreatment, the mass ratio of 3-chloroaniline: ethanol: catalyst DCyPP. Pd (OAc)₂: potassium carbonate 13: 16-20: 0.5-1.0: 24-28; in the pretreatment, nitrogen is introduced to remove air in the trickle bed reactor, and then carbon monoxide is introduced into the trickle bed reactor.

4. The process for producing ethyl m-aminobenzoate according to claim 1, characterized in that: in the continuous production, the pressure in the trickle bed reactor is kept between 0.1 and 0.15MPa, and the reaction temperature is 90 ℃.

Technical Field

The invention belongs to the technical field of chemical industry, and particularly relates to a production process of ethyl m-aminobenzoate.

Background

In recent years, with the development and progress of novel energy chemical technologies such as coal chemical industry, shale gas chemical industry, biomass chemical industry and the like, the carbon-I (C1) chemical technology for preparing organic basic chemical raw materials and fuels by replacing the traditional petrochemical process route is highly valued in academic and industrial fields, and becomes an important research direction of current energy chemistry and green chemistry. The C1 resource has the characteristic of wide source, generally comes from carbon-containing resources such as petroleum, coal, natural gas, biomass and the like, and in addition, the CO has important practical significance for realizing resource utilization as a cheap C1 resource. At present, the synthesis of ester by the carbonylation reaction with the participation of CO not only improves the atom utilization rate, but also becomes one of effective ways for high-value utilization of gas causing environmental pollution.

Ethyl m-aminobenzoate is a colorless oily liquid which is easily soluble in alcohol and ether, and slightly soluble in water, and is used as an organic synthesis intermediate. Wherein the ethyl m-aminobenzoate mesylate is a fish anesthetic.

Currently, ethyl m-aminobenzoate is obtained by esterification of m-aminobenzoic acid with ethanol in the presence of hydrochloric acid. The preparation method comprises cooling anhydrous ethanol at 10 deg.C or below, introducing hydrochloric acid until saturated, and adding dried m-aminobenzoic acid. Then heated to reflux for 24 h. Recovering ethanol, adding into ice water, neutralizing with sodium carbonate until pH is 8, washing with water to obtain crude product, and vacuum rectifying to obtain the final product. The process route is complex, concentrated hydrochloric acid is used as a catalyst, the catalytic efficiency is low, and the equipment is easy to corrode. In addition, the process route can generate a large amount of waste acid and hydrogen chloride gas, and the hydrogen chloride gas has pungent smell and is not beneficial to human health.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a production process of ethyl m-aminobenzoate.

A production process of ethyl m-aminobenzoate comprises the following steps:

preparing a catalyst: dissolving 1, 3-bis (dicyclohexylphosphino) propanebis (tetrafluoroborate) (DCyPP) and palladium acetate in a molar ratio of 1:1 in acetonitrile, crystallizing at 25 ℃ for 24 hours, and drying to obtain a catalyst DCyPP. Pd (OAc)₂；

Pretreatment: the catalyst DCyPP & Pd (OAc)₂Uniformly mixing with potassium carbonate, and adding into a trickle bed reactor; mixing 3-chloroaniline and ethanol to obtain a reaction raw material mixture A, wherein the ethanol is used as a reactant and a solvent;

continuous production: adding the reaction raw material mixture A into a trickle bed reactor, introducing carbon monoxide, keeping the pressure in the reactor at 0.1-0.2MPa, and reacting at 80-100 ℃ for 1-1.5 h; obtaining a mixture B after the reaction is finished;

and (3) purification: pumping the mixture B into a rectifying tower, controlling the temperature of the tower kettle of the rectifying tower at 120 ℃, cooling a low-boiling-point compound through a condenser to obtain a distillate C, measuring the content of ethyl aminobenzoate in the distillate C, mixing the distillate C with the reaction raw material mixture A for further recycling when the content of ethyl m-aminobenzoate is less than 0.1%, and returning the distillate to the tower kettle of the rectifying tower when the content of ethyl m-aminobenzoate is more than 0.1%; and (4) measuring the purity of the residual liquid at the bottom of the tower, wherein the purity of the residual liquid reaches more than 98.5 percent and is the target product D-m-aminobenzoic acid ethyl ester, otherwise, further rectifying by a reboiler.

Preferably, the carbon monoxide is introduced into the reactor after nitrogen is introduced into the pretreatment to remove air from the trickle reactor.

Preferably, the mass ratio of the 3-chloroaniline in the pretreatment is as follows: ethanol: catalyst DCyPP. Pd (OAc)₂: the ratio of potassium carbonate to the reaction raw materials is 13: 16-20: 0.5-1.0: 24-28.

Preferably, in the continuous production, the pressure in the reactor is maintained at 0.1-0.15MPa and the reaction temperature is 90 ℃.

The working principle is as follows: in a trickle bed reactor, 3-chloroaniline in a catalyst DCyPP. Pd (OAc)₂Under the action of the catalyst, removing halogen, and carrying out an interposing carbonyl esterification reaction with carbon monoxide and ethanol to obtain a target product, namely ethyl m-aminobenzoate, and rectifying and purifying the ethyl m-aminobenzoate by a rectifying tower.

The reaction equation that occurs is as follows:

the invention has the following beneficial effects:

1. the process disclosed in patent CN110642733A uses 3-nitrobenzoic acid and ethanol to perform esterification reaction by using concentrated sulfuric acid as a catalyst, and the purity of the product is only 98.3%. The invention adopts carbon monoxide to carry out carbonylation esterification reaction, improves the atom utilization rate, realizes the effective utilization of resources, and has the product purity as high as 99.0 percent.

2. The method can realize continuous production of the ethyl m-aminobenzoate, has the advantages of convenient and easily obtained reaction raw materials, simple process, mild reaction conditions, low reaction energy consumption, no waste acid in the reaction process and suitability for large-scale production.

3. The distillate generated in the reaction can be recycled after the components in the distillate are measured, so that the use of raw materials is saved, and the production cost is reduced; and the content of ethyl aminobenzoate in the reaction product is measured, so that the purity of the product is ensured, and the value of the product is improved.

Drawings

FIG. 1 is a flow chart of a production process of ethyl m-aminobenzoate.

Reference numerals: in the figure, 1 is a trickle bed reactor; 2 is a rectifying tower; 3 is a condenser; 4 is a reboiler; a is a reaction raw material mixture; b is a mixture after the reaction is finished; c is distillate; d is the product.

Detailed Description

The following are specific embodiments of the present invention and are further described with reference to the drawings, but the present invention is not limited to these embodiments.

Reaction raw materials: ethanol (commercial ethanol, content 99%); 3-chloroaniline (commercially available, 98% content); carbon monoxide (commercially available, content 99%); potassium carbonate (commercially available, content 98.5%); palladium acetate (commercially available, content 99%); DCyPP (commercially available, content 98%)

Preparing a catalyst: dissolving 1, 3-bis (dicyclohexylphosphino) propanebis (tetrafluoroborate) (DCyPP) and palladium acetate in a molar ratio of 1:1 in acetonitrile, crystallizing at 25 ℃ for 24 hours, and drying to obtain a catalyst DCyPP. Pd (OAc)₂；

Example 1:

a production process of ethyl m-aminobenzoate comprises the following steps:

pretreatment: introducing nitrogen to remove air in the trickle bed reactor, introducing carbon monoxide into the trickle bed reactor, uniformly mixing the catalyst DCyPP & Pd (OAc)2 and potassium carbonate, and then filling the mixture into the trickle bed reactor; mixing 3-chloroaniline and ethanol to obtain a reaction raw material mixture A; wherein, the mass ratio of 3-chloroaniline: ethanol: catalyst DCyPP. Pd (OAc)₂: potassium carbonate 13:20:1.0: 28;

continuous production: adding the reaction raw material mixture A into a trickle bed reactor, introducing carbon monoxide, keeping the pressure in the reactor at 0.2MPa, and reacting at 90 ℃ for 1.5 h; obtaining a mixture B after the reaction is finished;

and (3) purification: pumping the mixture B into a rectifying tower, controlling the temperature of the tower kettle of the rectifying tower at 120 ℃, cooling a low-boiling-point compound through a condenser to obtain a distillate C, measuring the content of ethyl aminobenzoate in the distillate C, mixing the distillate C with the reaction raw material mixture A for further recycling when the content of ethyl m-aminobenzoate is less than 0.1%, and returning the distillate to the tower kettle of the rectifying tower when the content of ethyl m-aminobenzoate is more than 0.1%; and (4) measuring the purity of the residual liquid at the bottom of the tower, wherein the purity of the residual liquid reaches 98.5 percent and is the target product D-m-aminobenzoic acid ethyl ester, otherwise, further rectifying by a reboiler.

Example 2

A production process of ethyl m-aminobenzoate comprises the following steps:

pretreatment: after nitrogen was introduced to remove air from the trickle bed reactor, carbon monoxide was introduced into the trickle bed reactor, and a catalyst DCyPP. Pd (OAc)₂Mixing with potassium carbonate, and loading into trickle bed reactor; mixing 3-chloroaniline and ethanol to obtain a reaction raw material mixture A; wherein, the mass ratio of 3-chloroaniline: ethanol: catalyst DCyPP. Pd (OAc)₂: potassium carbonate 13:18:0.7: 26.

Continuous production: adding the reaction raw material mixture A into a trickle bed reactor, introducing carbon monoxide, keeping the pressure in the reactor at 0.15MPa, and reacting for 1.5h at 90 ℃; obtaining a mixture B after the reaction is finished;

and (3) purification: pumping the mixture B into a rectifying tower, controlling the temperature of the tower kettle of the rectifying tower at 120 ℃, cooling a low-boiling-point compound through a condenser to obtain a distillate C, measuring the content of ethyl aminobenzoate in the distillate C, mixing the distillate C with the reaction raw material mixture A for further recycling when the content of ethyl m-aminobenzoate is less than 0.1%, and returning the distillate to the tower kettle of the rectifying tower when the content of ethyl m-aminobenzoate is more than 0.1%; and (4) measuring the purity of the residual liquid at the bottom of the tower, wherein the purity of the residual liquid reaches more than 99.0 percent and is the target product D-m-aminobenzoic acid ethyl ester, otherwise, further rectifying by a reboiler.

Example 3

A production process of ethyl m-aminobenzoate comprises the following steps:

pretreatment: after nitrogen was introduced to remove air from the trickle bed reactor, carbon monoxide was introduced into the trickle bed reactor, and a catalyst DCyPP. Pd (OAc)₂Mixing with potassium carbonate, and loading into trickle bed reactor; mixing 3-chloroaniline and ethanol to obtain a reaction raw material mixture A; wherein, the mass ratio of 3-chloroaniline: ethanol: catalyst DCyPP. Pd (OAc)₂: potassium carbonate 13:18:0.6: 26.

Continuous production: adding the reaction raw material mixture A into a trickle bed reactor according to a preset proportion, introducing carbon monoxide, keeping the pressure in the reactor at 0.12MPa, and reacting for 1h at 100 ℃; obtaining a mixture B after the reaction is finished;

and (3) purification: pumping the mixture B into a rectifying tower, controlling the temperature of the tower kettle of the rectifying tower at 120 ℃, cooling a low-boiling-point compound through a condenser to obtain a distillate C, measuring the content of ethyl aminobenzoate in the distillate C, mixing the distillate C with the reaction raw material mixture A for further recycling when the content of ethyl m-aminobenzoate is less than 0.1%, and returning the distillate to the tower kettle of the rectifying tower when the content of ethyl m-aminobenzoate is more than 0.1%; and (4) measuring the purity of the residual liquid at the bottom of the tower, wherein the purity of the residual liquid reaches more than 98.9 percent and is the target product D-m-aminobenzoic acid ethyl ester, otherwise, further rectifying by a reboiler.

Example 4

A production process of ethyl m-aminobenzoate comprises the following steps:

pretreatment: after nitrogen was introduced to remove air from the trickle bed reactor, carbon monoxide was introduced into the trickle bed reactor, and a catalyst DCyPP. Pd (OAc)₂Mixing with potassium carbonate, and loading into trickle bed reactor; mixing 3-chloroaniline and ethanol to obtain a reaction raw material mixture A; wherein, the mass ratio of 3-chloroaniline: ethanol: catalyst DCyPP. Pd (OAc)₂: potassium carbonate 13:16:0.5: 24.

Continuous production: adding the reaction raw material mixture A into a trickle bed reactor according to a preset proportion, introducing carbon monoxide, keeping the pressure in the reactor at 0.1MPa, and reacting for 1.3h at 80 ℃; obtaining a mixture B after the reaction is finished;

and (3) purification: pumping the mixture B into a rectifying tower, controlling the temperature of the tower kettle of the rectifying tower at 120 ℃, cooling a low-boiling-point compound through a condenser to obtain a distillate C, measuring the content of ethyl aminobenzoate in the distillate C, mixing the distillate C with the reaction raw material mixture A for further recycling when the content of ethyl m-aminobenzoate is less than 0.1%, and returning the distillate to the tower kettle of the rectifying tower when the content of ethyl m-aminobenzoate is more than 0.1%; and (4) measuring the purity of the residual liquid at the bottom of the tower, wherein the purity of the residual liquid reaches 98.7 percent and is the target product D-m-aminobenzoic acid ethyl ester, otherwise, further rectifying by a reboiler.