阅读说明：本技术 一种氯甲酸乙酯精馏釜残的处理方法 (Treatment method of ethyl chloroformate rectification kettle residue ) 是由 严绘 石苏洋 王明晨 侯嘉 韩小文 李梅 马荣慧 殷恒志 于 2021-08-25 设计创作，主要内容包括：本申请公开了一种氯甲酸乙酯精馏釜残的处理方法,将氯甲酸乙酯精馏釜残与乙醇进一步反应,可以将釜残中的氯甲酸乙酯基本反应完全,提高了碳酸二乙酯含量,釜残组分较为单一,便于制备高品质碳酸二乙酯；经乙醇处理后的釜残,脱溶脱出乙醇后,进行连续化分子蒸馏,体系温度低,停留时间短,碳酸二乙酯受热时间短,产品色度、含量、稳定性等显著优于传统精馏工艺。氯甲酸乙酯精馏釜残得到有效资源化处理,获得高品质碳酸二乙酯,大幅降低三废量,提高了产品附加值。(The application discloses a treatment method of ethyl chloroformate rectification kettle residues, wherein the ethyl chloroformate rectification kettle residues are further reacted with ethanol, so that the ethyl chloroformate in the kettle residues can be basically and completely reacted, the content of diethyl carbonate is improved, the components of the kettle residues are single, and high-quality diethyl carbonate can be conveniently prepared; after the ethanol is removed from the kettle residue after ethanol treatment, continuous molecular distillation is carried out, the system temperature is low, the retention time is short, the heating time of diethyl carbonate is short, and the product chromaticity, content, stability and the like are obviously superior to those of the traditional rectification process. The ethyl chloroformate rectification kettle residue is effectively recycled to obtain high-quality diethyl carbonate, the three wastes are greatly reduced, and the added value of the product is improved.)

1. A treatment method of ethyl chloroformate rectification residue is characterized by comprising the following steps:

adding ethyl chloroformate rectification kettle residue into a reaction kettle, and calculating the amount of ethanol added into the reaction kettle according to the content of ethyl chloroformate in the kettle residue to completely react the ethyl chloroformate, wherein the molar ratio of the ethanol to the ethyl chloroformate in the kettle residue is 1: 1-10: 1, the reaction temperature is 30-80 ℃, and the reaction time is 1-10 h;

adding the reacted kettle residue into a desolventizing tower, and carrying out desolventizing treatment at 10KPa-100KPa until the ethanol content in the desolventizing tower is less than 0.5%;

and adding the residual materials in the desolventizing tower into a molecular distiller for distillation and purification to prepare diethyl carbonate meeting the requirements, wherein the molecular distillation vacuum is 1Pa-100Pa, the molecular distillation temperature is 50-110 ℃, and the molecular distillation material residence time is 10-600 s.

2. The method for treating ethyl chloroformate rectification residue according to claim 1, wherein the molar ratio of the ethanol to the ethyl chloroformate in the residue is 2: 1-5: 1.

3. the method for treating ethyl chloroformate rectification residue according to claim 1, wherein the reaction temperature is 50 ℃ to 80 ℃.

4. The method for treating ethyl chloroformate rectification kettle residue according to claim 1, characterized in that the desolventizing vacuum is 10KPa to 30 KPa.

5. The method for treating ethyl chloroformate rectification residue according to claim 1, wherein the molecular distillation vacuum is 1Pa to 10 Pa.

6. The method for treating ethyl chloroformate rectification kettle residue according to claim 5, characterized in that the molecular distillation temperature is 70 ℃ to 90 ℃.

7. The method for treating ethyl chloroformate rectification kettle residue according to claim 6, characterized in that the molecular distillation material residence time is 30s-60 s.

Technical Field

The application relates to the field of waste treatment in chemical production, in particular to a method for treating ethyl chloroformate rectifying still residues.

Background

Ethyl chloroformate, a colorless transparent liquid, is mainly used as an intermediate for manufacturing various products, organic synthesis, chemical solvents, chemical products for producing medicines, herbicides and the like, such as cefazolin (pioneer 5), tetrazoleacetic acid, nicosulfuron and the like, and can also be used as a solvent and an amino protective agent. Diethyl carbonate is used as a solvent for cellulose nitrate, synthetic resins and natural resins in chemical production, and is used for manufacturing pyrethrin, sealing stationary liquid and the like, and high-purity diethyl carbonate is mainly used for lithium ion battery electrolyte.

The current industrialized preparation method of ethyl chloroformate mainly comprises continuous tower synthesis of ethanol and phosgene, and the finished product is obtained by polishing and rectifying the synthetic liquid. In the synthesis process, a small amount of ethyl chloroformate can generate side reaction with raw material ethanol, the diethyl carbonate is generated through further reaction, the content of the diethyl carbonate is about 1% -3%, the diethyl carbonate exists in kettle residue in the rectification process of the ethyl chloroformate, and the components in the kettle residue mainly comprise ethyl chloroformate, diethyl carbonate and heavy components. The conventional treatment method is to collect a plurality of batches of kettle residues and then further rectify the kettle residues, and the product has low chroma and content due to long-time distillation of the kettle residues, can only meet the indexes of industrial products and has low added value of the product. In order to improve the chromaticity of the product industrially, activated carbon is adopted for decolorization, and the decolorized waste activated carbon is used as solid waste, so that the amount of three wastes is increased.

Patent CN102304048B describes a method for refining high-purity diethyl carbonate, which mainly comprises three steps of light component collection, side-line discharge process adjustment and product collection by improving a rectification device to separate light components. The raw material of the process is industrial grade 99.5% diethyl carbonate, and the product purity is high. The high-purity diethyl carbonate is obtained by rectification separation, and the kettle residue treatment technology is not involved. Patent CN105669460A describes a method for co-producing glycol from diethyl carbonate, which uses cyclic carbonate and ethanol as raw materials to synthesize diethyl carbonate and ethylene glycol as a byproduct by transesterification. The method for purifying diethyl carbonate is a rectification method, mainly relates to the aspects of synthesis and refining, and does not introduce a kettle residue treatment scheme.

The currently reported method for refining diethyl carbonate is mainly purification by a rectification scheme, the raw material is industrial grade diethyl carbonate, and a process for preparing diethyl carbonate by purifying kettle residue is not involved. The by-product diethyl carbonate of phosgene method ethyl chloroformate technology, on one hand because ethyl chloroformate rectification is purified, the chroma of still residue is higher, the direct rectification product quality is poorer. Meanwhile, the kettle residue contains more components, so that the purity is not high and the refining difficulty is high. The purification is carried out by adopting a rectification mode, the energy consumption is high, and meanwhile, the product has poor chromaticity after long-time rectification.

Disclosure of Invention

The application provides a treatment method of ethyl chloroformate rectification kettle residues, which solves the problems that a phosgene ethyl chloroformate rectification kettle residue treatment scheme is not provided in the prior art, and the quality of a by-product diethyl carbonate after simple rectification is low.

In order to solve the technical problem, the application provides a method for treating ethyl chloroformate rectification kettle residues, which comprises the following steps:

adding ethyl chloroformate rectification kettle residue into a reaction kettle, and calculating the amount of ethanol added into the reaction kettle according to the content of ethyl chloroformate in the kettle residue to completely react the ethyl chloroformate, wherein the molar ratio of the ethanol to the ethyl chloroformate in the kettle residue is 1: 1-10: 1, the reaction temperature is 30-80 ℃, and the reaction time is 1-10 h;

adding the reacted kettle residue into a desolventizing tower, and carrying out desolventizing treatment at 10KPa-100KPa until the ethanol content in the desolventizing tower is less than 0.5%;

and adding the residual materials in the desolventizing tower into a molecular distiller for distillation and purification to prepare diethyl carbonate meeting the requirements, wherein the molecular distillation vacuum is 1Pa-100Pa, the molecular distillation temperature is 50-110 ℃, and the molecular distillation material residence time is 10-600 s.

Preferably, the mole ratio of the ethanol to the ethyl chloroformate in the still residue is 2: 1-5: 1.

preferably, the reaction temperature is 50 ℃ to 80 ℃.

Preferably, the desolventizing vacuum is 10KPa to 30 KPa.

Preferably, the molecular distillation vacuum is 1Pa to 10 Pa.

Preferably, the molecular distillation temperature is 70 ℃ to 90 ℃.

Preferably, the molecular distillation mass residence time is between 30s and 60 s.

Compared with the prior art, the method for treating the ethyl chloroformate rectification kettle residue provided by the application comprises the steps of firstly adding the ethyl chloroformate rectification kettle residue into a reaction kettle, and calculating the amount of ethanol added into the reaction kettle according to the content of the ethyl chloroformate in the kettle residue so as to completely react the ethyl chloroformate, wherein the molar ratio of the ethanol to the ethyl chloroformate in the kettle residue is 1: 1-10: 1, the reaction temperature is 30-80 ℃, and the reaction time is 1-10 h; adding the reacted kettle residue into a desolventizing tower, and carrying out desolventizing treatment at 10KPa-100KPa until the content of ethanol in the desolventizing tower is less than 0.5%; and finally, adding the residual materials in the desolventizing tower into a molecular distiller for distillation and purification to prepare diethyl carbonate meeting the requirements, wherein the molecular distillation vacuum is 1Pa-100Pa, the molecular distillation temperature is 50-110 ℃, and the molecular distillation material residence time is 10s-600 s.

Therefore, by applying the treatment method, the ethyl chloroformate rectification kettle residue is further reacted with ethanol, the ethyl chloroformate in the kettle residue can be basically and completely reacted, the content of diethyl carbonate is improved, the components of the kettle residue are single, and the preparation of high-quality diethyl carbonate is facilitated; after the ethanol is removed from the kettle residue after ethanol treatment, continuous molecular distillation is carried out, the system temperature is low, the retention time is short, the heating time of diethyl carbonate is short, and the product chromaticity, content, stability and the like are obviously superior to those of the traditional rectification process. The ethyl chloroformate rectification kettle residue is effectively recycled to obtain high-quality diethyl carbonate, the three wastes are greatly reduced, and the added value of the product is improved.

Drawings

In order to more clearly explain the technical solution of the present application, the drawings needed to be used in the embodiments are briefly described below, and it is obvious to those skilled in the art that other drawings can be obtained according to the drawings without making any inventive changes.

FIG. 1 is a flow chart of a method for treating ethyl chloroformate distillation still residue according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a method for treating ethyl chloroformate distillation residue according to an embodiment of the present invention;

FIG. 3 is a reaction equation of ethyl chloroformate and ethanol according to an embodiment of the present invention.

Detailed Description

In order to make those skilled in the art better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be described clearly and completely with reference to the accompanying drawings.

The core of the application is to provide a treatment method of ethyl chloroformate rectification kettle residues, which can solve the problems that a phosgene ethyl chloroformate rectification kettle residue treatment scheme is not provided in the prior art, and the quality of a by-product diethyl carbonate after simple rectification is low and the like.

Fig. 1 is a flowchart of a method for processing ethyl chloroformate rectification residue according to an embodiment of the present invention, fig. 2 is a schematic diagram of a method for processing ethyl chloroformate rectification residue according to an embodiment of the present invention, and fig. 3 is a reaction equation of ethyl chloroformate and ethanol according to an embodiment of the present invention, as shown in fig. 1 to fig. 3, the method includes the following steps:

s101: adding ethyl chloroformate into the reaction kettle to rectify the kettle residue, and calculating the amount of ethanol added into the reaction kettle according to the content of the ethyl chloroformate in the kettle residue to completely react the ethyl chloroformate, wherein the molar ratio of the ethanol to the ethyl chloroformate in the kettle residue is 1: 1-10: 1, the reaction temperature is 30-80 ℃, and the reaction time is 1-10 h.

S102: adding the reacted kettle residue into a desolventizing tower, and carrying out desolventizing treatment at 10KPa-100KPa until the ethanol content in the desolventizing tower is less than 0.5%. The purpose of this step is to remove excess ethanol.

S103: and adding the residual materials in the desolventizing tower into a molecular distiller for distillation and purification to prepare diethyl carbonate meeting the requirements, wherein the molecular distillation vacuum is 1Pa-100Pa, the molecular distillation temperature is 50-110 ℃, and the molecular distillation material residence time is 10s-600 s.

The residue in this example is phosgene ethyl chloroformate rectification residue, and the main components are ethyl chloroformate, diethyl carbonate and heavy components. Table 1 shows the quality standards of diethyl carbonate (HG/T5157-2017):

TABLE 1

As a preferred embodiment, the molar ratio of ethanol to ethyl chloroformate in the bottoms is 2: 1-5: 1. as a preferred embodiment, the reaction temperature is from 50 ℃ to 80 ℃. As a preferred embodiment, the desolventizing vacuum is between 10KPa and 30 KPa. As a preferred embodiment, the molecular distillation vacuum is between 1Pa and 10 Pa. As a preferred embodiment, the molecular distillation temperature is from 70 ℃ to 90 ℃. As a preferred embodiment, the molecular distillation mass residence time is in the range of from 30s to 60 s.

In order that those skilled in the art will better understand the present solution, the detailed description of the present solution is provided below in specific examples, which use the same starting materials and compositions: 15% of ethyl chloroformate, 80% of diethyl carbonate and 5% of heavy components.

Example 1

300Kg of ethyl chloroformate rectification kettle residue is added into a 500L reaction kettle, 45Kg of ethyl chloroformate is converted, 38.33Kg of absolute ethanol is dropwise added into the kettle under the stirring state, and the mol ratio of the ethanol to the ethyl chloroformate is 2: 1; the temperature is raised to 60 ℃ and the reaction time is 5 h. And (3) desolventizing the synthetic liquid under the negative pressure of 10KPa, collecting excessive ethanol and a small amount of light components from the top of the tower, and finishing desolventizing when the top of the tower is basically not collected, wherein the ethanol content in the bottom of the tower is 0.2%. Feeding the tower bottom material into a molecular distiller for distillation at a certain speed, and respectively collecting light components, diethyl carbonate main fractions and heavy components. The vacuum of the molecular distillation device is 10Pa, the temperature is 80 ℃, and the material retention time is 30 s; the content of the main fraction of the diethyl carbonate is 99.97 percent, the other indexes meet the requirement of high-purity quality indexes, and the yield of the diethyl carbonate is 85.2 percent.

Example 2

300Kg of ethyl chloroformate rectification residue obtained in example 1 (the same applies below) was charged into a 500-liter reaction vessel, and 19.2Kg of anhydrous ethanol was added dropwise to the vessel while stirring, wherein the molar ratio of ethanol to ethyl chloroformate was 1: 1; the temperature is increased to 70 ℃ and the reaction time is 8 h. Desolventizing the synthetic liquid under the negative pressure of 100KPa, collecting a small amount of light components from the top of the tower, and completing desolventizing when the top of the tower is basically not collected, wherein the ethanol content in the tower kettle is 0.05 percent. Feeding the tower bottom material into a molecular distiller for distillation at a certain speed, and respectively collecting light components, diethyl carbonate main fractions and heavy components. The vacuum of the molecular distillation device is 5Pa, the temperature is 70 ℃, and the material retention time is 100 s; the content of the main fraction of the diethyl carbonate is 99.95 percent, the other indexes meet the quality index requirements of superior products, and the yield of the diethyl carbonate is 80.3 percent.

Example 3

300Kg of ethyl chloroformate rectification residue obtained in example 1 was charged into a 500L reactor, and 192Kg of anhydrous ethanol was added dropwise to the reactor while stirring, the molar ratio of ethanol to ethyl chloroformate being 10: 1; the temperature is increased to 80 ℃ and the reaction time is 4 h. And (3) desolventizing the synthetic liquid under the negative pressure of 20KPa, collecting excessive ethanol and a small amount of light components from the top of the tower, and finishing desolventizing when the top of the tower is basically not collected, wherein the ethanol content in the bottom of the tower is 0.13%. Feeding the tower bottom material into a molecular distiller for distillation at a certain speed, and respectively collecting light components, diethyl carbonate main fractions and heavy components. The vacuum of the molecular distillation device is 20Pa, the temperature is 90 ℃, and the material retention time is 200 s; the content of the main fraction of the diethyl carbonate is 99.99 percent, the other indexes meet the requirement of electronic grade quality indexes, and the yield of the diethyl carbonate is 83.3 percent.

Example 4

300Kg of ethyl chloroformate rectification residue obtained in example 1 was charged into a 500-liter reaction vessel, and in the state of stirring, 96Kg of anhydrous ethanol was added dropwise to the vessel, wherein the mol ratio of ethanol to ethyl chloroformate was 5: 1; the temperature is increased to 50 ℃ and the reaction time is 10 h. And (3) desolventizing the synthetic liquid under the negative pressure of 30KPa, collecting excessive ethanol and a small amount of light components from the top of the tower, and finishing desolventizing when the top of the tower is basically not collected, wherein the ethanol content in the bottom of the tower is 0.08%. Feeding the tower bottom material into a molecular distiller for distillation at a certain speed, and respectively collecting light components, diethyl carbonate main fractions and heavy components. The vacuum of the molecular distillation device is 100Pa, the temperature is 110 ℃, and the material retention time is 600 s; the content of the main fraction of diethyl carbonate is 99.96 percent, the other indexes meet the quality index requirements of superior products, and the yield of diethyl carbonate is 88.3 percent.

Example 5

300Kg of ethyl chloroformate rectification residue obtained in example 1 was charged into a 500-liter reaction vessel, and in the state of stirring, 57.6Kg of anhydrous ethanol was added dropwise to the vessel, wherein the mol ratio of ethanol to ethyl chloroformate was 3: 1; the temperature is increased to 70 ℃ and the reaction time is 6 h. And (3) desolventizing the synthetic liquid under the negative pressure of 10KPa, collecting excessive ethanol and a small amount of light components from the top of the tower, and finishing desolventizing when the top of the tower is basically not collected, wherein the ethanol content in the bottom of the tower is 0.05%. Feeding the tower bottom material into a molecular distiller for distillation at a certain speed, and respectively collecting light components, diethyl carbonate main fractions and heavy components. The vacuum of the molecular distillation device is 15Pa, the temperature is 90 ℃, and the material retention time is 30 s; the content of the main fraction of diethyl carbonate is 99.99 percent, the other indexes meet the requirement of electronic grade quality indexes, and the yield of diethyl carbonate is 87.8 percent.

Example 6

300Kg of ethyl chloroformate rectification residue obtained in example 1 was charged into a 500-liter reaction vessel, and in the state of stirring, 134.4Kg of anhydrous ethanol was added dropwise to the vessel, wherein the mol ratio of ethanol to ethyl chloroformate was 7: 1; the temperature is increased to 80 ℃ and the reaction time is 1 h. And (3) desolventizing the synthetic liquid under the negative pressure of 30KPa, collecting excessive ethanol and a small amount of light components from the top of the tower, and finishing desolventizing when the top of the tower is basically not collected, wherein the ethanol content in the bottom of the tower is 0.15%. Feeding the tower bottom material into a molecular distiller for distillation at a certain speed, and respectively collecting light components, diethyl carbonate main fractions and heavy components. The vacuum of the molecular distillation device is 80Pa, the temperature is 100 ℃, and the material retention time is 120 s; the content of the main fraction of the diethyl carbonate is 99.98 percent, the other indexes meet the requirement of high-purity grade quality indexes, and the yield of the diethyl carbonate is 86.2 percent.

The application provides a method for processing ethyl chloroformate rectification kettle residues, which comprises the steps of firstly adding the ethyl chloroformate rectification kettle residues into a reaction kettle, and calculating the amount of ethanol added into the reaction kettle according to the content of the ethyl chloroformate in the kettle residues so as to completely react the ethyl chloroformate, wherein the molar ratio of the ethanol to the ethyl chloroformate in the kettle residues is 1: 1-10: 1, the reaction temperature is 30-80 ℃, and the reaction time is 1-10 h; adding the reacted kettle residue into a desolventizing tower, and carrying out desolventizing treatment at 10KPa-100KPa until the content of ethanol in the desolventizing tower is less than 0.5%; and finally, adding the residual materials in the desolventizing tower into a molecular distiller for distillation and purification to prepare diethyl carbonate meeting the requirements, wherein the molecular distillation vacuum is 1Pa-100Pa, the molecular distillation temperature is 50-110 ℃, and the molecular distillation material residence time is 10s-600 s.

Therefore, by applying the treatment method, the ethyl formate rectification kettle residue is further reacted with ethanol, the ethyl chloroformate in the kettle residue can be basically and completely reacted, the content of diethyl carbonate is improved, the components of the kettle residue are single, and the preparation of high-quality diethyl carbonate is facilitated; after the ethanol is removed from the kettle residue after ethanol treatment, continuous molecular distillation is carried out, the system temperature is low, the retention time is short, the heating time of diethyl carbonate is short, and the product chromaticity, content, stability and the like are obviously superior to those of the traditional rectification process. The ethyl chloroformate rectification kettle residue is effectively recycled to obtain high-quality diethyl carbonate, the three wastes are greatly reduced, and the added value of the product is improved.

Other embodiments of the present application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the application and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims.

It will be understood that the present application is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The above-described embodiments of the present application do not limit the scope of the present application.