CN112409174A - Preparation device and method of 3, 3-methyl dimethacrylate - Google Patents
Preparation device and method of 3, 3-methyl dimethacrylate Download PDFInfo
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- CN112409174A CN112409174A CN202011345575.9A CN202011345575A CN112409174A CN 112409174 A CN112409174 A CN 112409174A CN 202011345575 A CN202011345575 A CN 202011345575A CN 112409174 A CN112409174 A CN 112409174A
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/08—Preparation of carboxylic acid esters by reacting carboxylic acids or symmetrical anhydrides with the hydroxy or O-metal group of organic compounds
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
- B01J31/02—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides
- B01J31/0277—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides comprising ionic liquids, as components in catalyst systems or catalysts per se, the ionic liquid compounds being used in the molten state at the respective reaction temperature
- B01J31/0278—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides comprising ionic liquids, as components in catalyst systems or catalysts per se, the ionic liquid compounds being used in the molten state at the respective reaction temperature containing nitrogen as cationic centre
- B01J31/0281—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides comprising ionic liquids, as components in catalyst systems or catalysts per se, the ionic liquid compounds being used in the molten state at the respective reaction temperature containing nitrogen as cationic centre the nitrogen being a ring member
- B01J31/0282—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides comprising ionic liquids, as components in catalyst systems or catalysts per se, the ionic liquid compounds being used in the molten state at the respective reaction temperature containing nitrogen as cationic centre the nitrogen being a ring member of an aliphatic ring, e.g. morpholinium
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/48—Separation; Purification; Stabilisation; Use of additives
- C07C67/52—Separation; Purification; Stabilisation; Use of additives by change in the physical state, e.g. crystallisation
- C07C67/54—Separation; Purification; Stabilisation; Use of additives by change in the physical state, e.g. crystallisation by distillation
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2231/00—Catalytic reactions performed with catalysts classified in B01J31/00
- B01J2231/40—Substitution reactions at carbon centres, e.g. C-C or C-X, i.e. carbon-hetero atom, cross-coupling, C-H activation or ring-opening reactions
- B01J2231/49—Esterification or transesterification
Abstract
The invention discloses a preparation device and a preparation method of 3, 3-dimethyl methyl acrylate. The self-design device comprises a reaction kettle, a reaction reflux and distillation condenser, a rectifying kettle, a rectifying tower section and a rectifying tower top condenser; the reaction kettle is connected with a reaction reflux and distillation condenser through a pipeline; the reaction reflux and distillation condenser is connected with the rectifying still through a pipeline; the rectifying kettle is connected with the rectifying tower section; the top of the rectifying tower section is connected with a condenser at the top of the rectifying tower through a pipeline; the condenser at the top of the rectifying tower is connected with the reaction kettle through a pipeline. The invention uses the ionic liquid as the catalyst of the esterification reaction of 3, 3-dimethyl acrylic acid, on the self-designed preparation device, the reaction process is synchronous with the separation of 3, 3-dimethyl methyl acrylate and/or water, the ionic liquid catalyst is repeatedly used for 5 times, and the average reaction yield is 90.7%. Provides a safe, economic, green and environment-friendly preparation device and method for producing 3, 3-dimethyl methyl acrylate on an industrial scale.
Description
Technical Field
The invention belongs to the technical field of chemistry and chemical engineering, and particularly relates to a preparation device and a preparation method of 3, 3-dimethyl methyl acrylate.
Background
The boiling point of the 3, 3-dimethyl methyl acrylate is 136.5 ℃ under normal pressure, and the 3, 3-dimethyl methyl acrylate is stable to heat under a neutral environment, is an important organic synthetic raw material and is used as an intermediate of medicines and pesticides, such as: can be used for preparing isotretinoin, piroctone, etc.
At present, 3-dimethylacrylic acid and methanol are generally mixed in industrial production, concentrated sulfuric acid is added as a catalyst, stirring reflux reaction is carried out at the temperature of 60-70 ℃, water is added after cooling, a water layer is removed, sulfuric acid is removed, an organic layer is taken, the water layer is extracted by dichloromethane, the organic layer is combined, then diluted sodium bicarbonate solution is used for washing, water washing is carried out, anhydrous magnesium sulfate is used for drying, dichloromethane is recovered by distillation, distillation is carried out, and the fraction at the temperature of 130-140 ℃ is 3, 3-dimethylacrylic acid methyl ester, and the reaction equation is as follows:
the process has many problems in actual production, firstly, the catalyst concentrated sulfuric acid cannot be recycled and reused because water is generated in the reaction, and the generated waste acid brings pressure to the treatment of three wastes; secondly, halogenated hydrocarbons such as dichloromethane and the like are used as extraction solvents in the process, so that the cost is increased and the environment is polluted; thirdly, drying agents such as anhydrous magnesium sulfate and the like are used in the process, so that the solid waste amount is increased, and pressure is brought to three-waste treatment; fourthly, the esterification reaction is a reversible reaction, and the yield is improved to ensure that the main raw material 3, 3-dimethylacrylic acid achieves the maximum effective conversion, preferably the methyl 3, 3-dimethylacrylate and/or water generated in the reaction are continuously removed in the reaction process, so that the problem comes about that the methyl 3, 3-dimethylacrylate and/or water generated in the reaction are continuously removed, generally, the methyl 3, 3-dimethylacrylate and/or water generated in the reaction are continuously distilled and removed in the reaction process, but the methyl alcohol is taken as a reaction raw material and is distilled out together in the distillation process because the boiling point of the methyl alcohol is relatively low, and the conversion reaction of the 3, 3-dimethylacrylic acid is more beneficial theoretically as the amount of the methyl in the system is larger.
Therefore, the methyl 3, 3-dimethacrylate and/or water generated by the reaction are removed by a distillation method, and simultaneously the methanol is firstly evaporated, so that the methanol in the reaction system is reduced, a certain amount of methanol is required to be kept in the reaction system, the methanol is required to be continuously supplemented, the methanol is required to be timely recovered for reducing the methanol consumption and is applied to the reaction system, a tower is required to be added for rectification for realizing the effective separation of the methanol, the methyl 3, 3-dimethacrylate and the water, a rectifying tower is directly added on a reaction kettle, a higher kettle temperature (namely reaction temperature) is required for separating the methyl 3, 3-dimethacrylate and/or the water generated by the reaction while the methanol is effectively separated, the generation of byproducts is increased due to the high reaction temperature, the decomposition of the methyl 3, 3-dimethacrylate is promoted, and only the methanol can be separated if the temperature is reduced, but cannot effectively remove the 3, 3-dimethyl methyl acrylate and/or water generated in the reaction.
Disclosure of Invention
The invention aims to provide a device and a method for preparing 3, 3-dimethyl methyl acrylate aiming at the defects of the prior art.
The technical scheme adopted by the invention for solving the technical problems is as follows:
the preparation device of the 3, 3-dimethyl methyl acrylate comprises a reaction kettle (a), a reaction reflux and distillation condenser (b), a rectifying kettle (c), a rectifying tower section (d) and a rectifying tower top condenser (e). The reaction kettle (a) is connected with a reaction reflux and distillation condenser (b) through a pipeline; the reaction reflux and distillation condenser (b) is connected with the rectifying still (c) through a pipeline; the rectifying kettle (c) is connected with a rectifying tower section (d); the top of the rectifying tower section (d) is connected with a rectifying tower top condenser (e) through a pipeline; the rectifying tower top condenser (e) is connected with the reaction kettle (a) through a pipeline to form a circulating preparation device of the 3, 3-dimethyl methyl acrylate, and is shown in figure 1.
The reaction kettle (a) and the rectifying kettle (c) are generally glass lining kettles; the reaction reflux and distillation condenser (b), the rectifying tower section (d) and the rectifying tower top condenser (e) are generally made of stainless steel materials; the pipeline material is generally stainless steel material; corrugated plate packing is arranged in the rectifying tower section (d), and other kinds of packing can be used.
The preparation method of the 3, 3-dimethyl methyl acrylate comprises the following technical processes:
and (1) putting 3, 3-dimethylacrylic acid, methanol and an ionic liquid catalyst into a reaction kettle (a), heating, carrying out reflux reaction for 4-6 hours through a reaction reflux and distillation condenser (b), switching a valve, changing the reflux reaction into a distillation reaction, and distilling out methanol and part of 3, 3-dimethylacrylic acid methyl ester and water generated in the reaction into a rectifying kettle (c).
The weight ratio of the 3, 3-dimethylacrylic acid, the methanol and the ionic liquid in the step (1) is preferably 1: 1.5-3: 0.1 to 0.2; the kind of the ionic liquid catalyst is not particularly limited, and N- (3-sulfopropyl) -N-methylpyrrolidone bisulfate ionic liquid is preferred; the preferable temperature of the reflux reaction and the distillation reaction is 68-75 ℃.
And (2) after the distillation reaction in the step (1) is started, starting the distillation separation in the distillation kettle (c), distilling out methanol from the condenser (e) at the top of the distillation tower by adjusting the reflux ratio, returning the distilled methanol to the reaction kettle (a), supplementing the methanol reduced in the distillation reaction, forming a methanol cycle, continuing for 12-18 hours until the reaction is complete, and accumulating the 3, 3-dimethyl methyl acrylate and water distilled out in the distillation reaction in the distillation kettle (c).
The temperature of the rectifying kettle (c) in the step (2) is preferably controlled to be 65-85 ℃, and the rectifying reflux ratio is preferably 1-20.
Step (3), when the reaction is complete, continuing the distillation reaction in the reaction kettle (a) until the internal temperature is 85 ℃; and (c) continuously rectifying in the rectifying kettle to separate out methanol, switching a valve, and separating out the methanol to a receiving tank (g).
The methanol in the receiving tank (g) in the step (3) can be directly used for a batch of reaction.
And (4) cooling the reaction kettle (a) to 40 ℃, carrying out reduced pressure distillation until the internal temperature is 85 ℃, collecting the distilled crude product of the 3, 3-dimethyl methyl acrylate in a receiving tank (f), and pumping the crude product to a rectifying kettle (c) after the reduced pressure distillation is finished. And (3) cooling the reaction kettle (a) to 40 ℃, discharging the rest ionic liquid catalyst, dehydrating, controlling the water content of the ionic liquid catalyst to be less than 3%, and returning the ionic liquid catalyst to the reaction kettle (a) for the next batch of reaction.
The vacuum degree of reduced pressure distillation in the step (4) is generally-0.085 to-0.095 MPa, and the ionic liquid catalyst can be used for only 5 times.
And (5) continuing rectifying and separating in the rectifying still (c) until the temperature of the tower top is 70 ℃. And (3) cooling the kettle to 35 ℃, standing for layering, removing a water layer from the bottom of the rectifying kettle (c), refining the water, collecting a fraction at 130-135 ℃, and obtaining 3, 3-dimethyl methyl acrylate in a receiving tank (h), wherein the GC purity is over 99 percent, the water content is below 0.2 percent, and the average molar yield is about 90.7 percent.
The invention has the following beneficial effects:
the present invention has been made to overcome the above problems occurring in the actual process, and extensive studies have been made to avoid the above problems, and as a result, it has been found that: firstly, the ionic liquid is used as an esterification catalyst of 3, 3-dimethyl acrylic acid instead of concentrated sulfuric acid, and the catalyst can be simply and repeatedly applied; and secondly, a self-designed reaction device is used, the reaction process is synchronously carried out with the separation of the 3, 3-dimethyl methyl acrylate and/or the water, the generated 3, 3-dimethyl methyl acrylate and the water are continuously removed during the reaction, the stock of the raw material methanol participating in the reaction is not influenced, the using amount of the methanol is reduced, the reaction temperature is kept stable, byproducts are reduced, and good yield is obtained. The 3, 3-dimethyl methyl acrylate is distilled, refluxed and water-separated, so that the post-treatment mode is simplified, the use of halogenated hydrocarbon extracting agents such as dichloromethane and the like is avoided, and the use of drying agents such as anhydrous magnesium sulfate and the like is avoided.
The invention realizes that the ionic liquid is used as the catalyst, the distillation reaction and the rectification separation are synchronous during the reaction, the 3, 3-dimethyl methyl acrylate and the water generated by the reaction are continuously removed, the esterification reaction is further promoted, the good yield is obtained, and the simple and repeated application of the catalyst is realized, which are important improvements on the production process of the 3, 3-dimethyl methyl acrylate. Provides a safe, economic, green and environment-friendly preparation device and method for producing 3, 3-dimethyl methyl acrylate on an industrial scale.
Drawings
FIG. 1 is a process flow diagram of the present invention;
in the figure, a reaction kettle (a), a reaction reflux and distillation condenser (b), a rectifying kettle (c), a rectifying tower section (d), a rectifying tower top condenser (e), a first receiving tank (f), a second receiving tank (g), a third receiving tank (h) and a fourth receiving tank (i).
Detailed Description
The invention is further illustrated by the following specific examples.
Example 1
Preparation of N- (3-sulfopropyl) -N-methylpyrrolidone bisulfate ionic liquid:
72kg of N-methylpyrrolidone (0.726kmol) and 88.5kg of 1, 3-propane sultone (0.725kmol) were put into a 500L reactor, stirred for 30min, and then heated to 35 ℃ to react for 24 hours. Cooling to below 10 ℃ by using brine ice, beginning to drop 71.5kg of concentrated sulfuric acid (0.729kmol), stirring for 30min after dropping, then heating to 80 ℃, carrying out heat preservation reaction for 14 hours, cooling to below 50 ℃ after the reaction is finished, adding 232kg of methanol, uniformly stirring, and barreling for later use to obtain 460kg of 50% N- (3-sulfopropyl) -N-methylpyrrolidone hydrogen sulfate ionic liquid methanol solution.
Examples 2 to 7
Preparation of methyl 3, 3-dimethacrylate:
step (1), putting 1000kg of 3, 3-dimethylacrylic acid (9.99kmol), 1600kg of methanol (49.94kmol) and 200kg of 50% N- (3-sulfopropyl) -N-methylpyrrolidone bisulfate ionic liquid methanol solution into a 5000L reaction kettle in sequence, stirring and heating to 68-75 ℃, carrying out reflux reaction for 5 hours, carrying out distillation reaction, and distilling out a mixture of methanol, 3-dimethylacrylic acid methyl ester and water while reacting to a 3000L rectification kettle.
And (2) after the distillation reaction of the reaction kettle is started, the rectification of the rectification kettle is started, the methanol distilled from the tower top flows into the reaction kettle, the temperature of the rectification kettle is controlled to be 65-85 ℃, the methanol is circulated in the system by controlling the temperature of the reaction kettle and adjusting the reflux ratio, and the 3, 3-dimethyl methyl acrylate and water generated by the reaction are accumulated in the rectification kettle, so that the circulation reaction is carried out for 16 hours.
After the reaction in the step (3) is finished, continuously distilling the reaction kettle of 5000L at normal pressure until the internal temperature is 85 ℃; and continuously rectifying the methanol collected by the rectifying still to a storage tank, stopping the temperature at 70 ℃ at the top of the tower, and collecting the methanol for the next batch of reaction.
And (4) cooling the reaction kettle to 40 ℃, carrying out reduced pressure distillation under the pressure of-0.09 MPa to the internal temperature of 85 ℃, collecting the distilled crude product of the 3, 3-dimethyl methyl acrylate into a receiving tank, and pumping the crude product of the 3, 3-dimethyl methyl acrylate into a rectifying kettle after the reduced pressure distillation is finished. The temperature of the reaction kettle is reduced to 40 ℃, the ionic liquid catalyst is discharged, the ionic liquid catalyst is sent to a 500L distillation kettle, after dehydration treatment, the water content of the ionic liquid catalyst is measured to be 2.4%, and the ionic liquid catalyst is sent to the next batch of reaction. Under the condition that other process conditions are not changed, the ionic liquid catalyst is continuously used for 5 times, see table 1, examples 3-7, wherein 20kg of 50% N- (3-sulfopropyl) -N-methylpyrrolidone hydrogen sulfate ionic liquid is supplemented when the ionic liquid catalyst is used for the 3 rd time in example 5.
And (5) continuously rectifying and separating the rectifying still until the temperature of the tower top is 70 ℃, reducing the temperature of the rectifying still to 35 ℃, collecting the distilled methanol in a storage tank, and applying the methanol in the next batch of reaction. Standing the rectifying still for 2 hours, layering, discharging a water layer from the bottom part of the rectifying still, collecting a fraction at 130-135 ℃ after finishing rectifying the water to obtain 1035kg of 3, 3-dimethyl methyl acrylate (the yield is 90.8%), the GC purity is 99.2%, and the water content is 0.14%. TABLE 1
Example 8
Preparation of methyl 3, 3-dimethacrylate:
step (1) 200g of 3, 3-dimethylacrylic acid (2mol), 300g of methanol (9.36mol) and 20g N- (3-sulfopropyl) -N-methylpyrrolidone bisulfate ionic liquid are sequentially put into a 1000ml reaction bottle, the temperature is raised to 75 ℃, after reflux reaction is carried out for 6 hours, distillation reaction is carried out, and a mixture of the methanol, the 3, 3-dimethylacrylic acid methyl ester and water is distilled out while reaction is carried out, and then the mixture is put into a rectification bottle.
And (3) after the distillation reaction in the step (2) is started, rectifying the methanol distilled from the tower top, and allowing the methanol to flow back to the reaction bottle, wherein the temperature in the rectification bottle is controlled to be 65-85 ℃, the methanol is circulated in the system by controlling the reaction temperature and adjusting the reflux ratio, and the methyl 3, 3-dimethacrylate and water generated by the reaction are accumulated in the rectification bottle step by step, so that the circular reaction is carried out for 12 hours.
After the reaction in the step (3) is finished, continuously distilling the reaction bottle at normal pressure until the internal temperature is 85 ℃; the rectifying bottle continues to rectify and collect the methanol until the temperature at the top of the tower reaches 70 ℃, and the methanol is collected and sleeved in the next batch of reaction.
And (4) cooling the reaction bottle to 40 ℃, distilling under reduced pressure at the pressure of-0.095 MPa to the internal temperature of 85 ℃, and adding the distilled crude product of the methyl 3, 3-dimethacrylate into a rectification bottle. And continuously distilling the rest ionic liquid catalyst under reduced pressure until the internal temperature is 100 ℃, keeping the temperature at 100 ℃ for 3 hours, and measuring the water content of the ionic liquid catalyst to be 2.2 percent after cooling.
And (5) continuously rectifying and separating the rectifying bottle until the temperature at the top of the tower is 70 ℃, and directly mechanically using the collected methanol for the next batch of reaction. And cooling the rectifying bottle to 35 ℃, standing for 1 hour, layering, separating a water layer, collecting 130-135 ℃ fractions after finishing refining the fractions, and obtaining 212g of 3, 3-dimethyl methyl acrylate (the yield is 93.0%), the GC purity is 99.5% and the water content is 0.2%.
Example 9
Preparation of methyl 3, 3-dimethacrylate:
step (1) 200g of 3, 3-dimethylacrylic acid (2mol), 300g of methanol (9.36mol) and the residual N- (3-sulfopropyl) -N-methylpyrrolidone bisulfate ionic liquid catalyst in the example 8 are sequentially put into a 1000ml reaction bottle, the temperature is raised to 75 ℃, after the reflux reaction is carried out for 6 hours, the distillation reaction is carried out, and a mixture of the methanol, the 3, 3-dimethylacrylic acid methyl ester and water is distilled out while the reaction is carried out, and then the mixture is put into a rectification bottle.
And (3) after the distillation reaction in the step (2) is started, rectifying the methanol distilled from the tower top, and allowing the methanol to flow back to the reaction bottle, wherein the temperature in the rectification bottle is controlled to be 65-85 ℃, the methanol is circulated in the system by controlling the reaction temperature and adjusting the reflux ratio, and the methyl 3, 3-dimethacrylate and water generated by the reaction are gradually accumulated in the rectification bottle, so that the circulation reaction is carried out for 12 hours.
After the reaction in the step (3) is finished, continuously distilling the reaction bottle at normal pressure until the internal temperature is 85 ℃; the rectifying bottle continues to rectify and collect the methanol until the temperature at the top of the tower reaches 70 ℃, and the methanol is collected and sleeved in the next batch of reaction.
And (4) cooling the reaction bottle to 40 ℃, distilling under reduced pressure at the pressure of-0.095 MPa to the internal temperature of 85 ℃, and adding the distilled crude product of the methyl 3, 3-dimethacrylate into a rectification bottle. And continuously distilling the rest ionic liquid catalyst under reduced pressure until the internal temperature is 100 ℃, keeping the temperature at 100 ℃ for 3 hours, and measuring the water content of the ionic liquid catalyst to be 2.7 percent after cooling.
And (5) continuously rectifying and separating the rectifying bottle until the temperature at the top of the tower is 70 ℃, and directly mechanically using the collected methanol for the next batch of reaction. And cooling the rectifying bottle to 35 ℃, standing for 1 hour, layering, separating out a water layer, collecting 130-135 ℃ fractions after finishing refining the fractions, and obtaining 211g of 3, 3-dimethyl methyl acrylate (the yield is 92.5%), the GC purity is 99.3% and the water content is 0.17%.
Example 10
Preparation of methyl 3, 3-dimethacrylate:
step (1) 200g of 3, 3-dimethylacrylic acid (2mol), 600g of methanol (18.72mol) and 10g N- (3-sulfopropyl) -N-methylpyrrolidone bisulfate ionic liquid are sequentially put into a 1000ml reaction bottle, stirred and heated to 75 ℃, and subjected to reflux reaction for 4 hours, then the distillation reaction is carried out, and a mixture of the methanol, the 3, 3-dimethylacrylic acid methyl ester and water is distilled out while the reaction is carried out, and then the mixture is put into a rectification bottle.
And (3) after the distillation reaction in the step (2) is started, rectifying the methanol distilled from the tower top, and allowing the methanol to flow back to the reaction bottle, wherein the temperature in the rectification bottle is controlled to be 65-85 ℃, the methanol is circulated in the system by controlling the reaction temperature and adjusting the reflux ratio, and the methyl 3, 3-dimethacrylate and water generated by the reaction are gradually accumulated in the rectification bottle, so that the circulation reaction is carried out for 18 hours.
After the reaction in the step (3) is finished, continuously distilling the reaction bottle at normal pressure until the internal temperature is 85 ℃; the rectifying bottle continues to rectify and collect the methanol until the temperature at the top of the tower reaches 70 ℃, and the methanol is collected and sleeved in the next batch of reaction.
And (4) cooling the reaction bottle to 40 ℃, distilling under reduced pressure at-0.085 MPa to reach an internal temperature of 85 ℃, and adding the distilled crude product of the methyl 3, 3-dimethacrylate into a rectifying bottle. And continuously distilling the rest ionic liquid catalyst under reduced pressure until the internal temperature is 100 ℃, keeping the temperature at 100 ℃ for 2 hours, and measuring the water content of the ionic liquid catalyst to be 2.3 percent after cooling.
And (5) continuously rectifying and separating the rectifying bottle until the temperature at the top of the tower is 70 ℃, and directly mechanically using the collected methanol for the next batch of reaction. And cooling the rectifying bottle to 35 ℃, standing for 1 hour, layering, separating a water layer, collecting fractions at 130-135 ℃ after finishing refining the fractions, and obtaining 213g of 3, 3-dimethyl methyl acrylate (yield 93.4%), GC purity 99.4% and water content 0.18%.
Example 11
Preparation of methyl 3, 3-dimethacrylate:
step (1) 200g of 3, 3-dimethylacrylic acid (2mol), 600g of methanol (18.72mol) and the residual N- (3-sulfopropyl) -N-methylpyrrolidone bisulfate ionic liquid catalyst in the example 10 are sequentially put into a 1000ml reaction bottle, the temperature is raised to 75 ℃, after reflux reaction is carried out for 4 hours, distillation reaction is carried out, and a mixture of the methanol, the 3, 3-dimethylacrylic acid methyl ester and water is distilled out while reaction is carried out to a rectification bottle.
And (3) after the distillation reaction in the step (2) is started, rectifying the methanol distilled from the tower top, and allowing the methanol to flow back to the reaction bottle, wherein the temperature in the rectification bottle is controlled to be 65-85 ℃, the methanol is circulated in the system by controlling the reaction temperature and adjusting the reflux ratio, and the methyl 3, 3-dimethacrylate and water generated by the reaction are gradually accumulated in the rectification bottle, so that the circulation reaction is carried out for 18 hours.
Step (3), after the reaction is finished, continuously distilling the reaction bottle at normal pressure until the internal temperature is 85 ℃; the rectifying bottle continues to rectify and collect the methanol until the temperature at the top of the tower reaches 70 ℃, and the methanol is collected and sleeved in the next batch of reaction.
And (4) cooling the reaction bottle to 40 ℃, distilling under reduced pressure at-0.085 MPa to reach an internal temperature of 85 ℃, and adding the distilled crude product of the methyl 3, 3-dimethacrylate into a rectifying bottle. And continuously distilling the rest ionic liquid catalyst under reduced pressure until the internal temperature is 100 ℃, keeping the temperature at 100 ℃ for 2 hours, and measuring the water content of the ionic liquid catalyst to be 2.6 percent after cooling.
And (5) continuously rectifying and separating the rectifying bottle until the temperature at the top of the tower is 70 ℃, and directly mechanically using the collected methanol for the next batch of reaction. And cooling the rectifying bottle to 35 ℃, standing for 1 hour, layering, separating a water layer, collecting fractions at 130-135 ℃ after finishing rectifying the water, and obtaining 215g of 3, 3-dimethyl methyl acrylate (the yield is 94.3%), the GC purity is 99.6% and the water content is 0.19%.
Claims (7)
1. A preparation device of 3, 3-dimethyl methyl acrylate is characterized by comprising a reaction kettle (a), a reaction reflux and distillation condenser (b), a rectifying kettle (c), a rectifying tower section (d) and a rectifying tower top condenser (e); the reaction kettle (a) is connected with a reaction reflux and distillation condenser (b) through a pipeline; the reaction reflux and distillation condenser (b) is connected with the rectifying still (c) through a pipeline; (ii) a The rectifying kettle (c) is connected with the rectifying tower section (d); (ii) a The top of the rectifying tower section (d) is connected with a condenser (e) at the top of the rectifying tower through a pipeline; (ii) a The condenser (e) at the top of the rectifying tower is connected with the reaction kettle (a) through a pipeline; a circulating preparation device of the methyl 3, 3-dimethacrylate is formed.
2. The apparatus for preparing 3, 3-dimethyl methyl acrylate according to claim 1, wherein the reaction vessel (a) and the rectifying vessel (c) are glass lining vessels; the reaction reflux and distillation condenser (b), the rectifying tower section (d) and the rectifying tower top condenser (e) are made of stainless steel materials; the pipeline is made of stainless steel material; the rectifying tower section (d) is filled with filler.
3. The apparatus for producing methyl 3, 3-dimethylacrylate according to claim 2 wherein corrugated plate packing is installed in said rectifying tower section (d).
4. A method for producing methyl 3, 3-dimethacrylate using the apparatus for producing methyl 3, 3-dimethacrylate according to claim 1, which comprises the steps of:
putting 3, 3-dimethylacrylic acid, methanol and an ionic liquid catalyst into a reaction kettle (a), heating, carrying out reflux reaction for 4-6 hours through a reaction reflux and distillation condenser (b), closing a reflux valve, opening a distillation valve towards a rectifying tower (c), changing the reflux reaction into a distillation reaction, and distilling out methanol and part of 3, 3-dimethylacrylic acid methyl ester and water generated in the reaction into the rectifying kettle (c);
step (2) after the distillation reaction in the step (1) is started, starting rectification separation in a rectification kettle (c), distilling off methanol from a condenser (e) at the top of the rectification tower by adjusting the reflux ratio, returning the distilled methanol to a reaction kettle (a), supplementing the methanol reduced by the distillation reaction, forming a methanol cycle, continuing for 12-18 hours till the reaction is complete, and accumulating the 3, 3-dimethyl methyl acrylate and water distilled out by the distillation reaction in the rectification kettle (c);
after the reaction is completed, continuing the distillation reaction in the reaction kettle (a) until the internal temperature is 85 ℃; continuously rectifying the methanol in the rectifying kettle (c) to separate out methanol, closing a reflux valve in the direction of the rectifying kettle (c) and opening a valve in the direction of the receiving tank (g), and shunting the methanol to a second receiving tank (g);
the methanol in the receiving tank (g) in the step (3) can be directly used for the next batch of reaction;
cooling the reaction kettle (a) to 40 ℃, carrying out reduced pressure distillation, ending when the internal temperature is raised to 85 ℃, collecting the distilled crude product of the 3, 3-dimethyl methyl acrylate into a first receiving tank (f), and pumping the crude product into a rectifying kettle (c) after the reduced pressure distillation is finished; cooling the reaction kettle (a) to 40 ℃ again, discharging the rest ionic liquid catalyst, performing dehydration treatment, controlling the water content of the ionic liquid catalyst to be less than 3%, and returning the ionic liquid catalyst to the reaction kettle (a) for the next batch of reaction;
continuously rectifying and separating the rectifying kettle (c) in the step (5) until the temperature at the tower top is 70 ℃; and then, reducing the temperature of a rectifying kettle (c) to 35 ℃, standing for layering, removing a water layer from the bottom of the rectifying kettle (c), collecting fractions at 130-135 ℃ after the water is distilled, and obtaining the 3, 3-dimethyl methyl acrylate in a receiving tank (h), wherein the GC purity is more than 99%, the water content is less than 0.2%, and the average molar yield is about 90.7%.
5. The method for preparing methyl 3, 3-dimethacrylate according to claim 4, wherein the weight ratio of the 3, 3-dimethylacrylic acid, the methanol and the ionic liquid in the step (1) is 1: (1.5-3): (0.1 to 0.2); the kind of the ionic liquid catalyst is not particularly limited, and N- (3-sulfopropyl) -N-methylpyrrolidone bisulfate ionic liquid is preferred; the preferable temperature of the reflux reaction and the distillation reaction is 68-75 ℃.
6. The method for preparing 3, 3-dimethyl methyl acrylate according to claim 5, wherein the temperature of the rectifying still (c) in the step (2) is controlled to be 65-85 ℃, and the rectifying reflux ratio is 1-20.
7. The process for preparing methyl 3, 3-dimethacrylate according to claim 4, 5 or 6, wherein the vacuum degree of the reduced pressure distillation in the step (4) is-0.085 to-0.095 MPa, and the ionic liquid catalyst can be used at least 5 times.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116272815A (en) * | 2023-05-17 | 2023-06-23 | 江苏省瑞丰高分子材料有限公司 | Quick switching device of reaction kettle and rectifying tower |
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| US3821286A (en) * | 1971-10-05 | 1974-06-28 | American Cyanamid Co | Process for the production of methyl methacrylate |
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