阅读说明：本技术 一种提纯3-乙氧基丙酸乙酯的方法 (Method for purifying ethyl 3-ethoxypropionate ) 是由 张春雨 蓝俊杰 于 2020-12-23 设计创作，主要内容包括：本发明公开了一种提纯3-乙氧基丙酸乙酯的方法,包括以下步骤：步骤一,备料；步骤二,混合；步骤三,中和；步骤四,回收；步骤五,提纯；其中在上述步骤一中,按照预定比例分别称取无水乙醇、丙烯酸乙酯、碱金属醇盐和固体酸备用；该发明增加过滤和精馏处理,无需碱洗分水处理,副反应少,无三废产生,降低了对环境的污染,且反应转化率高,提纯效果好,纯度易得99.8％以上,可以将3-乙氧基丙酸乙酯进一步加工为电子级,大大简化了分离过程,节省了资源的损耗,降低了3-乙氧基丙酸乙酯的生产成本,同时提纯流程简单,反应条件温和,便于人员操作,有利于3-乙氧基丙酸乙酯的大规模生产。(The invention discloses a method for purifying 3-ethoxy ethyl propionate, which comprises the following steps: step one, preparing materials; step two, mixing; step three, neutralizing; step four, recycling; step five, purification; in the first step, absolute ethyl alcohol, ethyl acrylate, alkali metal alkoxide and solid acid are respectively weighed according to a preset proportion for later use; the method adds filtration and rectification treatment, does not need alkali washing and water separation treatment, has less side reaction, does not generate three wastes, reduces the pollution to the environment, has high reaction conversion rate, good purification effect and high purity of over 99.8 percent, can further process the 3-ethoxy ethyl propionate into an electronic grade, greatly simplifies the separation process, saves the resource loss, reduces the production cost of the 3-ethoxy ethyl propionate, has simple purification flow and mild reaction conditions, is convenient for personnel to operate, and is favorable for large-scale production of the 3-ethoxy ethyl propionate.)

1. A method for purifying ethyl 3-ethoxypropionate, comprising the steps of: step one, preparing materials; step two, mixing; step three, neutralizing; step four, recycling; step five, purification; the method is characterized in that:

in the first step, absolute ethyl alcohol, ethyl acrylate, alkali metal alkoxide and solid acid are respectively weighed according to a preset proportion for later use;

pouring the absolute ethyl alcohol and the ethyl acrylate prepared in the step one into a stirring reaction kettle, adding the alkali metal alkoxide prepared in the step one, mixing and stirring uniformly at room temperature, and obtaining crude 3-ethoxy ethyl propionate and an alkaline solution after the reaction is finished;

in the third step, the solid acid prepared in the first step is poured into a stirring reaction kettle, mixed and stirred uniformly, heated and subjected to neutralization reaction with the alkaline solution obtained in the second step, and filtered to obtain a filter cake containing solid salt and a filtrate containing crude ethyl 3-ethoxypropionate and water;

drying and collecting the filter cake obtained in the third step to obtain a solid salt byproduct, injecting the filtrate obtained in the third step into a tower-type rectifying still, vacuumizing, mixing and stirring uniformly, carrying out primary heating to ensure that the filtrate is heated to be converted into steam, collecting the front fraction of the filtrate from the top of the tower after condensation and reflux, and adjusting the reflux ratio to respectively obtain unreacted absolute ethyl alcohol and ethyl acrylate and a small amount of crude 3-ethoxyethyl propionate;

and in the fifth step, the crude 3-ethoxy ethyl propionate obtained in the fourth step is reinjected into a tower-type rectifying still, the tower-type rectifying still is vacuumized, mixed and stirred uniformly, secondary heating is carried out, the temperature of the filtrate is raised to be converted into steam, the filtrate refined fraction is collected from the tower top after condensation and reflux, the filtrate refined fraction is completely rectified and cooled to the room temperature, and the refined 3-ethoxy ethyl propionate is obtained.

2. The method of claim 1, wherein the ethyl 3-ethoxypropionate is purified by: in the first step, the alkali metal alkoxide is any one of lithium methoxide, sodium ethoxide, potassium tert-butoxide and sodium tert-butoxide.

3. The method of claim 1, wherein the ethyl 3-ethoxypropionate is purified by: in the first step, the solid acid is any one of citric acid, succinic acid, tartaric acid and stearic acid.

4. The method of claim 1, wherein the ethyl 3-ethoxypropionate is purified by: in the second step, the rotating speed of the stirring reaction kettle is 60-100 r/min, and the reaction time is 7.5-8.5 h.

5. The method of claim 1, wherein the ethyl 3-ethoxypropionate is purified by: in the third step, the neutralization reaction temperature of the stirring reaction kettle is 20-30 ℃, and the reaction time is 2-4 h.

6. The method of claim 1, wherein the ethyl 3-ethoxypropionate is purified by: in the fourth step, the pressure of a tower kettle of the tower type rectifying kettle is 9-10 mmHg, the primary heating temperature is 80-120 ℃, and the primary heating time is 1-5 hours.

7. The method of claim 1, wherein the ethyl 3-ethoxypropionate is purified by: in the fifth step, the secondary heating temperature of the tower-type rectifying kettle is 125-140 ℃, and the secondary heating time is 3-8 hours.

8. The method for purifying ethyl 3-ethoxypropionate as claimed in claim 1, wherein the weight ratio of the anhydrous ethanol, ethyl acrylate, alkali metal alkoxide and solid acid is 200: 280: 400: 2-4: 0.5-2.

Technical Field

The invention relates to the technical field of chemical synthesis, in particular to a method for purifying 3-ethoxy ethyl propionate.

Background

The 3-ethoxy ethyl propionate is an important organic solvent and an organic synthesis intermediate, and is widely applied to the synthesis of coating industry, electronic industry and medical intermediates.

U.S. Pat. No. 5,5081285 uses ethyl alcohol and ethyl acrylate to obtain 3-ethoxy ethyl propionate under the catalysis of methanesulfonic acid, the reaction temperature is 120-130 ℃, the yield is 41%, the scheme needs pressure reaction, neutralization is needed after the reaction, a large amount of wastewater is generated, the production is inconvenient, the reaction temperature is high, the number of side reactions is large, and the cost is too high.

Patent CN200810061996.1 adopts alkali metals such as metal sodium and the like or alkali metal alcoholate as a catalyst, 3-ethoxy ethyl propionate is synthesized by absolute ethyl alcohol and ethyl acrylate, acid neutralization and alkaline water alkaline washing are needed after the reaction is finished, a large amount of waste water is generated, a separation step is also added, the side reaction is increased due to high heat release in the neutralization process, the purity of the product is within 99.8%, and the product cannot be further processed into an electronic grade product and is used in the photoelectric industry.

In addition, it is reported that the 3-ethoxy ethyl propionate is obtained by catalyzing absolute ethyl alcohol and ethyl acrylate with the strongly basic ion exchange resin, but the trace acid content in the absolute ethyl alcohol and the ethyl acrylate is generally 200-500 ppm, the strongly basic ion exchange resin can be neutralized to lose the catalytic effect, so that the consumption of the strongly basic ion exchange resin is large, about 20% of the mass of the ethyl acrylate is generally used, the strongly basic ion exchange resin for the catalyst is expensive and short in service life, generally loses the catalytic effect within 6-8 hours, needs to be regenerated, and can only be regenerated for 7 times at most, the strongly basic ion exchange resin is easy to break and lose the purpose, the conversion rate is not high, generally is 70-90%, the regenerated strongly basic ion exchange resin generates a large amount of wastewater, the production cost is greatly increased, and the large-scale production cannot be realized.

Therefore, it is necessary to design a method for purifying ethyl 3-ethoxypropionate.

Disclosure of Invention

The invention aims to provide a method for purifying 3-ethoxy ethyl propionate so as to solve the problems in the background technology.

In order to solve the technical problems, the invention provides the following technical scheme: a method for purifying ethyl 3-ethoxypropionate, comprising the steps of: step one, preparing materials; step two, mixing; step three, neutralizing; step four, recycling; step five, purification;

in the first step, absolute ethyl alcohol, ethyl acrylate, alkali metal alkoxide and solid acid are respectively weighed according to a preset proportion for later use;

pouring the absolute ethyl alcohol and the ethyl acrylate prepared in the step one into a stirring reaction kettle, adding the alkali metal alkoxide prepared in the step one, mixing and stirring uniformly at room temperature, and obtaining crude 3-ethoxy ethyl propionate and an alkaline solution after the reaction is finished;

in the third step, the solid acid prepared in the first step is poured into a stirring reaction kettle, mixed and stirred uniformly, heated and subjected to neutralization reaction with the alkaline solution obtained in the second step, and filtered to obtain a filter cake containing solid salt and a filtrate containing crude ethyl 3-ethoxypropionate and water;

drying and collecting the filter cake obtained in the third step to obtain a solid salt byproduct, injecting the filtrate obtained in the third step into a tower-type rectifying still, vacuumizing, mixing and stirring uniformly, carrying out primary heating to ensure that the filtrate is heated to be converted into steam, collecting the front fraction of the filtrate from the top of the tower after condensation and reflux, and adjusting the reflux ratio to respectively obtain unreacted absolute ethyl alcohol and ethyl acrylate and a small amount of crude 3-ethoxyethyl propionate;

and in the fifth step, the crude 3-ethoxy ethyl propionate obtained in the fourth step is reinjected into a tower-type rectifying still, the tower-type rectifying still is vacuumized, mixed and stirred uniformly, secondary heating is carried out, the temperature of the filtrate is raised to be converted into steam, the filtrate refined fraction is collected from the tower top after condensation and reflux, the filtrate refined fraction is completely rectified and cooled to the room temperature, and the refined 3-ethoxy ethyl propionate is obtained.

According to the technical scheme, in the step one, the alkali metal alkoxide is any one of lithium methoxide, sodium ethoxide, potassium tert-butoxide and sodium tert-butoxide.

According to the technical scheme, in the first step, the solid acid is any one of citric acid, succinic acid, tartaric acid and stearic acid.

According to the technical scheme, in the second step, the rotating speed of the stirring reaction kettle is 60-100 r/min, and the reaction time is 7.5-8.5 h.

According to the technical scheme, in the third step, the neutralization reaction temperature of the stirring reaction kettle is 20-30 ℃, and the reaction time is 2-4 hours.

According to the technical scheme, in the fourth step, the pressure of a tower kettle of the tower type rectifying kettle is 9-10 mmHg, the primary heating temperature is 80-120 ℃, and the primary heating time is 1-5 hours.

According to the technical scheme, in the fifth step, the secondary heating temperature of the tower-type rectifying kettle is 125-140 ℃, and the secondary heating time is 3-8 hours.

According to the technical scheme, the weight ratio of the absolute ethyl alcohol, the ethyl acrylate, the alkali metal alkoxide and the solid acid is preferably 200-280: 400: 2-4: 0.5-2.

Compared with the prior art, the invention has the following beneficial effects: the method for purifying the ethyl 3-ethoxypropionate does not need alkali washing and water separation treatment, has less side reaction, does not generate three wastes, reduces the pollution to the environment, has high reaction conversion rate, good purification effect and high purity of over 99.8 percent, can further process the ethyl 3-ethoxypropionate into an electronic grade, is used for the photoelectric industry, greatly simplifies the separation process, saves the loss of resources, reduces the production cost, has simple purification flow, mild reaction conditions, is convenient for personnel to operate, and is favorable for large-scale production.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is a flow chart of the method of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, the present invention provides a technical solution: a method for purifying ethyl 3-ethoxypropionate, comprising the steps of: step one, preparing materials; step two, mixing; step three, neutralizing; step four, recycling; step five, purification;

in the first step, anhydrous ethanol, ethyl acrylate, alkali metal alkoxide and solid acid are respectively weighed according to a preset proportion for later use, wherein the alkali metal alkoxide is any one of lithium methoxide, sodium ethoxide, potassium tert-butoxide and sodium tert-butoxide, and the solid acid is any one of citric acid, succinic acid, tartaric acid and stearic acid; the weight ratio of the absolute ethyl alcohol, the ethyl acrylate, the alkali metal alkoxide and the solid acid is 200-280: 400: 2-4: 0.5-2.

Pouring the absolute ethyl alcohol and the ethyl acrylate prepared in the step one into a stirring reaction kettle, adding the alkali metal alkoxide prepared in the step one, mixing and stirring uniformly at room temperature, obtaining crude 3-ethoxy ethyl propionate and an alkaline solution after the reaction is finished, wherein the rotating speed of the stirring reaction kettle is 60-100 r/min, and the reaction time is 7.5-8.5 hours;

pouring the solid acid prepared in the step one into a stirring reaction kettle, mixing and stirring uniformly, heating, and then carrying out neutralization reaction with the alkaline solution obtained in the step two, wherein the neutralization reaction temperature of the stirring reaction kettle is 20-30 ℃, the reaction time is 2-4 h, and filtering to obtain a filter cake containing solid salt and a filtrate containing crude 3-ethoxyethyl propionate and water;

drying and collecting the filter cake obtained in the third step to obtain a solid salt byproduct, injecting the filtrate obtained in the third step into a tower-type rectifying still, vacuumizing, mixing and stirring uniformly, and carrying out primary heating, wherein the pressure of the tower still of the tower-type rectifying still is 9-10 mmHg, the primary heating temperature is 80-120 ℃, the primary heating time is 1-5 hours, the filtrate is heated to be converted into steam, the filtrate is condensed and refluxed, then the filtrate front fraction is collected from the top of the tower, and the reflux ratio is adjusted to respectively obtain unreacted absolute ethyl alcohol and ethyl acrylate, and a small amount of crude ethyl 3-ethoxypropionate;

and in the fifth step, the crude 3-ethoxy ethyl propionate obtained in the fourth step is reinjected into a tower-type rectifying still, the tower-type rectifying still is vacuumized, mixed and stirred uniformly and heated for the second time, the secondary heating temperature of the tower-type rectifying still is 125-140 ℃, the secondary heating time is 3-8 hours, the temperature of the filtrate is increased to be converted into steam, the filtrate is condensed and refluxed, the filtrate refined fraction is collected from the top of the tower, and the refined 3-ethoxy ethyl propionate is completely rectified and cooled to room temperature, so that the refined 3-ethoxy ethyl propionate is obtained.

Based on the above, the method has the advantages that the method optimizes the purification method of the ethyl 3-ethoxypropionate by adding filtration and rectification treatment, has high reaction conversion rate, good purification effect and high purity of over 99.8%, can further process the ethyl 3-ethoxypropionate into electronic grade, is used in the photoelectric industry, greatly simplifies the separation process, saves the resource loss, reduces the production cost of the ethyl 3-ethoxypropionate, has simple purification process, mild reaction conditions, is convenient for personnel to operate, is beneficial to large-scale production of the ethyl 3-ethoxypropionate, does not need alkali to wash out water, has few side reactions, does not generate three wastes, and reduces the pollution to the environment.

The following will explain the method of purifying methyl 3-methoxypropionate and its purity and the like in the examples of the present invention by specific examples.

Example 1

(1) Purification of ethyl 3-ethoxypropionate

In a 500L reaction kettle, 120 kg of absolute ethyl alcohol, 200 kg of ethyl acrylate and 1.6 kg of sodium ethoxide are added for reaction for 8 hours at room temperature.

After the reaction is finished, adding 0.5kg of citric acid for neutralization, filtering, drying a filter cake, recovering a condensate, mixing the condensate with the filtrate, pumping the filtrate into a rectifying still, starting a vacuum and reduced pressure rectifying tower (10mmHg), stirring the mixture in the tower still, heating the mixture to reflux, adjusting the reflux ratio, and sequentially collecting fractions:

A. the temperature of the tower top is 80-120 ℃, and unreacted absolute ethyl alcohol, ethyl acrylate and a small amount of ethyl 3-ethoxypropionate are collected as front cut fractions.

B. The temperature of the tower top is above 120 ℃, the product 3-ethoxy ethyl propionate is collected until the rectification is finished, and the product is cooled to room temperature after the rectification is finished.

The yield of the 3-ethoxy ethyl propionate is 98 percent, and the purity is more than 99.8 percent.

Example 2

(1) Purification of ethyl 3-ethoxypropionate

In a 500L reaction kettle, 120 kg of absolute ethyl alcohol, 200 kg of ethyl acrylate and 1.5 kg of sodium ethoxide are added for reaction for 8 hours at room temperature.

After the reaction is finished, adding 0.4kg of succinic acid for neutralization, filtering, drying a filter cake, recovering a condensate, merging the condensate with the filtrate, pumping the filtrate into a rectifying still, starting a vacuum and reduced pressure rectifying tower (10mmHg), stirring and heating the mixture to reflux, adjusting the reflux ratio, and sequentially collecting fractions:

A. the temperature of the tower top is 80-120 ℃, and unreacted absolute ethyl alcohol, ethyl acrylate and a small amount of ethyl 3-ethoxypropionate are collected as front cut fractions.

B. The temperature of the tower top is above 120 ℃, the product 3-ethoxy ethyl propionate is collected until the rectification is finished, and the product is cooled to room temperature after the rectification is finished.

The yield of the 3-ethoxy ethyl propionate is 98 percent, and the purity is more than 99.8 percent.

Example 3

(1) Purification of ethyl 3-ethoxypropionate

In a 500L reaction kettle, 120 kg of absolute ethyl alcohol, 200 kg of ethyl acrylate and 1.6 kg of sodium ethoxide are added for reaction for 8 hours at room temperature.

After the reaction is finished, adding 0.6kg of stearic acid for neutralization, filtering, drying a filter cake, recovering a condensate, merging the condensate with the filtrate, pumping the filtrate into a rectifying still, starting vacuum and decompressing for rectification (10mmHg), starting a tower still for stirring, heating to reflux, adjusting reflux ratio, and sequentially collecting each fraction:

A. the temperature of the tower top is 80-120 ℃, and unreacted absolute ethyl alcohol, ethyl acrylate and a small amount of ethyl 3-ethoxypropionate are collected as front cut fractions.

B. The temperature of the tower top is above 120 ℃, the product 3-ethoxy ethyl propionate is collected until the rectification is finished, and the product is cooled to room temperature after the rectification is finished.

The yield of the 3-ethoxy ethyl propionate is 98 percent, and the purity is more than 99.8 percent.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.