CN113200847A - Method for efficiently synthesizing methacrylic anhydride - Google Patents
Method for efficiently synthesizing methacrylic anhydride Download PDFInfo
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- CN113200847A CN113200847A CN202110501494.1A CN202110501494A CN113200847A CN 113200847 A CN113200847 A CN 113200847A CN 202110501494 A CN202110501494 A CN 202110501494A CN 113200847 A CN113200847 A CN 113200847A
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- methacrylic anhydride
- efficiently synthesizing
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/54—Preparation of carboxylic acid anhydrides
- C07C51/56—Preparation of carboxylic acid anhydrides from organic acids, their salts, their esters or their halides, e.g. by carboxylation
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/54—Preparation of carboxylic acid anhydrides
- C07C51/573—Separation; Purification; Stabilisation; Use of additives
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Abstract
The invention discloses a method for efficiently synthesizing methacrylic anhydride, belonging to the technical field of organic matter synthesis. Under the action of catalyst and polymerization inhibitor, methacrylic acid and acetic anhydride are synthesized into methacrylic anhydride. The method for efficiently synthesizing the methacrylic anhydride is simple and reasonable, has low raw material cost, uses a novel efficient catalyst, has mild reaction, high efficiency and higher product purity, and utilizes the reaction of the methacrylic acid and the acetic anhydride to generate the methacrylic anhydride.
Description
Technical Field
The invention relates to a method for efficiently synthesizing methacrylic anhydride, belonging to the technical field of organic matter synthesis.
Background
Methacrylic anhydride is a strong esterifying agent and is a necessary reagent for the preparation of sulfomethacrylates, methacrylamides, and methacrylic esters, especially esters of tertiary alcohols. Methacrylic anhydride can also be used as a crosslinking agent for synthesis of materials such as photocurable coatings and crosslinked resins.
The traditional synthetic route of methacrylic anhydride is prepared by reacting methacrylic acid with propylene chloride, but the route has the disadvantages of propylene chloride, active chemical property of propylene chloride and certain danger in the production process. The reaction route emerging at present is to synthesize methacrylic anhydride by reacting methacrylic acid with acetic anhydride, and the process route has the problems that: methacrylic acid is extremely easy to polymerize in the reaction process, the reaction time is long, the purification is difficult, and the like. The above factors restrict the production of methacrylic anhydride, resulting in the current dependence of the product on importation.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: provides a method for efficiently synthesizing methacrylic anhydride, which solves the problems of overlong reaction time, difficult purification, high raw material cost and the like in the prior art for preparing the methacrylic anhydride.
The technical problem to be solved by the invention is realized by adopting the following technical scheme:
a method for efficiently synthesizing methacrylic anhydride comprises the following steps:
a) feeding: weighing the components in a mass ratio of 2: 1, weighing a catalyst with the mass accounting for 0.8 percent of the total mass of the raw materials, preheating the methacrylic acid and the acetic anhydride, mixing the preheated methacrylic acid and the acetic anhydride together to obtain the raw materials, adding the weighed catalyst into the raw materials, and placing the three into a glass reaction kettle (5) for chemical reaction;
b) reaction: manufacturing a vacuum condition by using a vacuum pump, carrying out chemical reaction on the raw materials under the vacuum condition, stopping the reaction when no extraction is produced at the top of a rectifying tower, and obtaining a methacrylic anhydride crude product and an acetic acid crude product by adopting a chromatographic analysis method;
c) refluxing: weighing the polymerization inhibitor by using an electronic balance, wherein the mass of the polymerization inhibitor accounts for 0.2 percent of the total mass of the raw materials, condensing the crude acetic acid obtained in the step b), mixing the condensed crude acetic acid with the weighed polymerization inhibitor, and refluxing the crude acetic acid by using a low-temperature cooling liquid circulating pump and a rectifying tower to obtain a fine acetic acid product, wherein the reflux ratio is 2: 4;
d) separation: mixing the acetic acid refined product obtained in the step c) with the methacrylic anhydride crude product obtained in the step b), firstly extracting light components, extracting unreacted methacrylic acid, acetic anhydride and intermediate products, and separating by using a thorn-shaped fractionating column (4) after stabilization to obtain the methacrylic anhydride refined product.
As a preferred embodiment: the catalyst in the step a) is a c801 catalyst.
As a preferred embodiment: the reaction time in step b) was 6 hours.
As a preferred embodiment: the polymerization inhibitor in the step c) is I102 polymerization inhibitor.
As a preferred embodiment: measuring the pressure in the tower in the step b) by using a vacuum meter, controlling the pressure in the tower to be-85 KPa to-95 KPa, measuring the temperature in the glass reaction kettle (5) by using a first thermometer, controlling the temperature of the glass reaction kettle (5) to be 85 ℃ to 95 ℃, measuring the temperature at the top of the rectifying tower by using a second thermometer, and controlling the temperature at the top of the rectifying tower to be 50 ℃ to 55 ℃.
As a preferred embodiment: the reaction bath in the step a) is a HWCL-3 magnetic stirring reaction bath.
As a preferred embodiment: the vacuum pump in the step B) is an SHB-B95 type circulating water type multipurpose vacuum pump.
As a preferred embodiment: the low-temperature cooling liquid circulating pump is a DLSB-5/20 low-temperature cooling liquid circulating pump.
The invention has the beneficial effects that:
the invention provides a method for preparing methacrylic anhydride, which utilizes methacrylic acid to react with acetic anhydride to generate the methacrylic anhydride.
Drawings
FIG. 1 is a schematic view of the structure of a reaction apparatus of the present invention.
In the figure: 1. a vacuum system connection port; 2. a rectifying tower head; 3. receiving a system connection buckle; 4. a thorn-shaped fractionating column; 5. and (4) a glass reaction kettle.
Detailed Description
In order to make the technical means, the original characteristics, the achieved purpose and the efficacy of the invention easy to understand, the invention is further described with reference to the specific drawings.
As shown in fig. 1, the present invention provides an apparatus for a method for efficiently synthesizing methacrylic anhydride, comprising: 1000mL of a glass reaction vessel 5, a thermometer, a spur fractionating column 4, a rectifying column, a vacuum gauge, an electronic balance, an HWCL-3 magnetic stirring reaction bath, an SHB-B95 model circulating water type multipurpose vacuum pump, a DLSB-5/20 low-temperature cooling liquid circulating pump and a gas chromatograph.
The glass reaction kettle 5 comprises four connectors, the thorn-shaped fractionating column 4 is arranged on the middle connector of the glass reaction kettle 5, the rectifying tower is arranged on the thorn-shaped fractionating column 4, the thermometer comprises a first thermometer and a second thermometer, the first thermometer is arranged on the side connector of the glass reaction kettle 5, the second thermometer is arranged on the tower head of the rectifying tower, and the vacuum system connector 1 and the receiving system connector are further arranged on one side of the rectifying tower.
The thorn-shaped fractionating column 4 is a fractionating tube in which a plurality of groups of thorn-shaped objects are inclined downwards at intervals and are arranged in a spiral shape. The advantages of using the fractionating column are: the apparatus has simple assembly, convenient operation and less residual liquid in the fractionating column. The disadvantages are that: the packed column with the same length has low flow dividing efficiency and is suitable for separating a small amount of liquid with large boiling point difference.
The rectifying tower is a tower-type gas-liquid contact device for rectifying, and utilizes the property that each component in a mixture has different volatility, namely, the vapor pressure of each component is different at the same temperature, so that a light component (low-boiling-point substance) in a liquid phase is transferred to a gas phase, and a heavy component (high-boiling-point substance) in the gas phase is transferred to the liquid phase, thereby realizing the purpose of separation.
The method comprises the following steps:
a) feeding: weighing 516g of methacrylic acid and 258g of acetic anhydride by using an electronic balance, weighing 6.19g of catalyst which is c801 catalyst, preheating the methacrylic acid and the acetic anhydride, mixing the methacrylic acid and the acetic anhydride together to obtain a raw material, adding the weighed catalyst into the raw material, placing the raw material, the methacrylic acid and the acetic anhydride into a glass reaction kettle 5 for chemical reaction, and placing the glass reaction kettle 5 in a reaction bath.
The reaction bath is HWCL-3 magnetic stirring reaction bath, and the magnetic stirring reaction bath is a device which is combined with a magnetic stirrer to carry out multifunctional chemical reaction operation at low temperature.
b) Reaction: the vacuum condition is made by using a vacuum pump, which is an SHB-B95 model circulating water type multipurpose vacuum pump.
The vacuum pump refers to a device or equipment for obtaining vacuum by pumping a pumped container by using a mechanical, physical, chemical or physicochemical method. Vacuum pumps are devices that use various methods to improve, create and maintain a vacuum in an enclosed space.
Carrying out chemical reaction on the raw materials under a vacuum condition, stopping the reaction when no product is extracted from the top of the rectifying tower, wherein the reaction time is 6 hours, and obtaining a methacrylic anhydride crude product and an acetic acid crude product with the product content of 61% by adopting a chromatographic analysis method.
The nature of chromatographic analysis is the process of the distribution equilibrium of the molecules of the substance to be separated between the stationary phase and the mobile phase, the distribution of different substances between the two phases being different, which makes them move at different speeds with the mobile phase, and the different components of the mixture separate from each other on the stationary phase as the mobile phase moves.
The reaction principle is as follows:
c) refluxing: the polymerization inhibitor was weighed out by an electronic balance, I102 polymerization inhibitor, 1.55g by mass.
The polymerization inhibitor is an industrial aid, and is generally used to prevent the progress of polymerization. The polymerization inhibitor molecules react with chain radicals or low-activity radicals which cannot be initiated, thereby terminating the polymerization.
Condensing the crude acetic acid obtained in the step b), mixing the condensed crude acetic acid with a weighed polymerization inhibitor, and refluxing the crude acetic acid by using a low-temperature cooling liquid circulating pump and a rectifying tower to obtain a refined acetic acid product, wherein the reflux ratio is 2:4, and the rectifying tower is provided with a second thermometer.
Reflux is a chemical experimental phenomenon, and in order to accelerate some chemical reactions, which are slow or difficult to carry out, at room temperature, it is often necessary to keep the reactants boiling for a long time. In this case, a condensing means is required to allow the steam to be continuously condensed in the condensing pipe and returned to the reactor to prevent the escape of the reactor contents. Or sometimes the reactants are volatile, in order not to volatilize too quickly and lose them, a condenser tube is usually installed above the container of the reactants so that the vapor will flow back into the reaction vessel upon cooling.
In the chemical industry, in the rectification operation, after the ascending vapor extracted from the top of the rectification column is condensed by a condenser tube, a part of the liquid is sent out of the column as a distillate (overhead product), and the other part of the liquid is sent back into the column, which is called reflux.
d) Separation: mixing the refined acetic acid product obtained in the step c) with the crude methacrylic anhydride product obtained in the step b), firstly extracting light components, namely unreacted methacrylic acid, acetic anhydride and intermediate products, extracting the unreacted methacrylic acid, acetic anhydride and intermediate products, stabilizing, and separating by using a thorn-shaped fractionating column 4 to obtain the refined methacrylic anhydride product with the purity of 98%.
Measuring the pressure in the tower in the step b) by using a vacuum meter, controlling the pressure in the tower to be-85 to-95 KPa, measuring the temperature in the glass reaction kettle 5 by using a first thermometer, controlling the temperature of the glass reaction kettle 5 to be 85 to 95 ℃, measuring the temperature at the top of the rectifying tower by using a second thermometer, and controlling the temperature at the top of the rectifying tower to be 50 to 55 ℃.
The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations could be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions available to those skilled in the art through logic analysis, reasoning and limited experiments based on the prior art according to the concept of the present invention should be within the scope of protection defined by the claims.
Claims (8)
1. The method for efficiently synthesizing methacrylic anhydride is characterized by comprising the following steps:
a) feeding: weighing the components in a mass ratio of 2: 1, weighing a catalyst with the mass accounting for 0.8 percent of the total mass of the raw materials, preheating the methacrylic acid and the acetic anhydride, mixing the preheated methacrylic acid and the acetic anhydride together to obtain the raw materials, adding the weighed catalyst into the raw materials, and placing the three into a glass reaction kettle (5) for chemical reaction;
b) reaction: manufacturing a vacuum condition by using a vacuum pump, carrying out chemical reaction on the raw materials under the vacuum condition, stopping the reaction when no extraction is produced at the top of a rectifying tower, and obtaining a methacrylic anhydride crude product and an acetic acid crude product by adopting a chromatographic analysis method;
c) refluxing: weighing the polymerization inhibitor by using an electronic balance, wherein the mass of the polymerization inhibitor accounts for 0.2 percent of the total mass of the raw materials, condensing the crude acetic acid obtained in the step b), mixing the condensed crude acetic acid with the weighed polymerization inhibitor, and refluxing the crude acetic acid by using a low-temperature cooling liquid circulating pump and a rectifying tower to obtain a fine acetic acid product, wherein the reflux ratio is 2: 4;
d) separation: mixing the acetic acid refined product obtained in the step c) with the methacrylic anhydride crude product obtained in the step b), firstly extracting light components, extracting unreacted methacrylic acid, acetic anhydride and intermediate products, and separating by using a thorn-shaped fractionating column (4) after stabilization to obtain the methacrylic anhydride refined product.
2. The method for efficiently synthesizing methacrylic anhydride according to claim 1, wherein the catalyst in the step a) is a c801 catalyst.
3. The method for efficiently synthesizing methacrylic anhydride according to claim 1, wherein the reaction time in the step b) is 6 hours.
4. The method for efficiently synthesizing methacrylic anhydride according to claim 1, wherein the polymerization inhibitor in the step c) is I102 polymerization inhibitor.
5. The method for efficiently synthesizing methacrylic anhydride according to claim 1, wherein the pressure in the column in the step b) is measured by a vacuum gauge, the pressure in the column is controlled to be-85 to-95 KPa, the temperature in the glass reaction vessel (5) is measured by a first thermometer, the temperature in the glass reaction vessel (5) is controlled to be 85 to 95 ℃, the temperature at the top of the rectifying column is measured by a second thermometer, and the temperature at the top of the rectifying column is controlled to be 50 to 55 ℃.
6. The method for efficiently synthesizing methacrylic anhydride according to claim 1, wherein the reaction bath in the step a) is a HWCL-3 magnetic stirring reaction bath.
7. The method for efficiently synthesizing methacrylic anhydride according to claim 1, wherein the vacuum pump in the step B) is a circulating water type multipurpose vacuum pump of SHB-B95 type.
8. The method for efficiently synthesizing methacrylic anhydride according to claim 1, wherein the low-temperature cooling liquid circulating pump is a DLSB-5/20 low-temperature cooling liquid circulating pump.
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Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB965963A (en) * | 1959-10-09 | 1964-08-06 | Rohm & Haas | Acrylic methacrylic anhydride and polymers derived therefrom |
| CN1396149A (en) * | 2001-07-06 | 2003-02-12 | 阿托菲娜公司 | Method for preparing (methyl) acrylate anhydride |
| CN101205178A (en) * | 2006-12-18 | 2008-06-25 | 罗姆有限公司 | Improved method for the production of unsaturated carboxylic acid anhydrides |
| CN101486648A (en) * | 2009-01-08 | 2009-07-22 | 上海和创化学有限公司 | Preparation of allyl methacrylate |
| CN101939283A (en) * | 2008-02-08 | 2011-01-05 | 阿肯马法国公司 | Improved method for preparing (meth)acrylic anhydride |
| CN102105429A (en) * | 2008-08-05 | 2011-06-22 | 三菱丽阳株式会社 | Method for producing (meth)acrylic acid anhydride, method for storing (meth)acrylic acid anhydride, and method for producing (meth)acrylate ester |
| CN103058849A (en) * | 2013-01-19 | 2013-04-24 | 福州大学 | Interval reaction rectification process for synthesizing methacrylic anhydride |
| CN105418408A (en) * | 2015-12-15 | 2016-03-23 | 吴江市曙光化工有限公司 | Methacrylic anhydride reaction technology |
| CN106542998A (en) * | 2016-09-30 | 2017-03-29 | 万华化学集团股份有限公司 | It is a kind of to improve the selective preparation method of terminal olefin |
| CN108129293A (en) * | 2018-01-25 | 2018-06-08 | 杭州和利时自动化有限公司 | A kind of method of synthesizing methyl acrylic anhydride |
-
2021
- 2021-05-08 CN CN202110501494.1A patent/CN113200847A/en active Pending
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB965963A (en) * | 1959-10-09 | 1964-08-06 | Rohm & Haas | Acrylic methacrylic anhydride and polymers derived therefrom |
| CN1396149A (en) * | 2001-07-06 | 2003-02-12 | 阿托菲娜公司 | Method for preparing (methyl) acrylate anhydride |
| CN101205178A (en) * | 2006-12-18 | 2008-06-25 | 罗姆有限公司 | Improved method for the production of unsaturated carboxylic acid anhydrides |
| CN101939283A (en) * | 2008-02-08 | 2011-01-05 | 阿肯马法国公司 | Improved method for preparing (meth)acrylic anhydride |
| CN102105429A (en) * | 2008-08-05 | 2011-06-22 | 三菱丽阳株式会社 | Method for producing (meth)acrylic acid anhydride, method for storing (meth)acrylic acid anhydride, and method for producing (meth)acrylate ester |
| CN101486648A (en) * | 2009-01-08 | 2009-07-22 | 上海和创化学有限公司 | Preparation of allyl methacrylate |
| CN103058849A (en) * | 2013-01-19 | 2013-04-24 | 福州大学 | Interval reaction rectification process for synthesizing methacrylic anhydride |
| CN105418408A (en) * | 2015-12-15 | 2016-03-23 | 吴江市曙光化工有限公司 | Methacrylic anhydride reaction technology |
| CN106542998A (en) * | 2016-09-30 | 2017-03-29 | 万华化学集团股份有限公司 | It is a kind of to improve the selective preparation method of terminal olefin |
| CN108129293A (en) * | 2018-01-25 | 2018-06-08 | 杭州和利时自动化有限公司 | A kind of method of synthesizing methyl acrylic anhydride |
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