CN110759827A - Method for preparing ethyl acetate by catalytic esterification - Google Patents
Method for preparing ethyl acetate by catalytic esterification Download PDFInfo
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- CN110759827A CN110759827A CN201911083239.9A CN201911083239A CN110759827A CN 110759827 A CN110759827 A CN 110759827A CN 201911083239 A CN201911083239 A CN 201911083239A CN 110759827 A CN110759827 A CN 110759827A
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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
- B01J31/0284—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 aromatic ring, e.g. pyridinium
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- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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- 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
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Abstract
The invention relates to a method for preparing ethyl acetate by catalytic esterification, which comprises the following steps: the anion is ArSO3 ‑、BF4 ‑And HSO4 ‑The cation is [ NR ]4]+Adding ionic liquid of benzimidazole cation or imidazopyridine cation and ethanol into a reaction container; stirring the ionic solution in the reaction container, dropwise adding acetic acid, heating to 60-120 ℃ after dropwise adding, and continuously reacting for 2-12 h; after the reaction is finished, the organic phase is separated from the ionic liquid, the esterification yield is determined after the organic phase is washed, and the moisture in the ionic liquid is removed and then is recycled. The invention takes acetic acid and ethanol as reactants and takes the ionic liquid with anions of aryl sulfonic acid, boron tetrafluoride and hydrogen sulfate as the catalyst, the yield of ethyl acetate is higher, and the ionic liquid returnsAfter the compound is repeatedly used for 5 times after harvesting, the activity is not obviously reduced; the preparation method and the used equipment are simple, and the preparation process can not be corroded; toxic substances are not generated in the preparation process, so that the method is a green and efficient production method and has good industrial application prospect.
Description
Technical Field
The invention relates to the technical field of chemical industry, in particular to a method for preparing ethyl acetate by catalytic esterification.
Background
Ethyl acetate is an important chemical raw material, and is widely used as an excellent organic solvent and diluent in the synthesis of dyes, medicines, perfumes and the like. In addition, ethyl acetate is an environmentally friendly organic solvent that is commonly used in paints, coatings and inks, thereby avoiding the use of certain aromatic compounds. At present, the industrial production method of ethyl acetate mainly comprises a Fischer esterification method, an acetic acid/ethylene addition method and an acetaldehyde condensation method. The acetic acid esterification method and the ethanol dehydrogenation method are mainly adopted in the industry of China for production.
The conventional processes for preparing ethyl acetate have some disadvantages, the conventional esterification and addition of acetic acid to ethylene require a storage tank and various processing equipment, and the use of concentrated sulfuric acid as a catalyst causes corrosion of the apparatus; acetaldehyde employed in the acetaldehyde condensation process is only available in petrochemical industry sectors and is difficult to handle due to its toxicity. Therefore, there is an urgent need to find a more green and efficient process for producing ethyl acetate.
Ionic Liquids (ILs), so-called low temperature molten salts, are organic materials that are composed entirely of organic cations and organic/inorganic anions and have melting points below 100 ℃ (usually near or below room temperature). Due to its unique structure, ILs have excellent properties including low volatility, low flammability, excellent solubility, high stability, broad electrochemistryAs the ionic liquid has been discovered, the ionic liquid enters the rapid development period and has made remarkable progress in various research fields in the last two decades, for example, Chinese patent 200810027005.8 discloses a method for synthesizing ethyl acetate by ionic liquid catalytic continuous esterification rectification, acetic acid, ethanol and ionic liquid catalyst α -pyrrolidone hydrogen sulfate are added at the bottom of a rectifying tower in a certain proportion, upper heat preservation, lower heat preservation, kettle temperature and reflux ratio are set, after heating to the top of the tower to generate reflux liquid, total reflux is kept for 15 minutes, then mixed solution of ethanol and acetic acid is continuously added into an esterification kettle from an overhead tank at a certain feeding alcohol-acid ratio and feeding flow rate, the reflux ratio is opened, the ethyl acetate is continuously prepared by reactive rectification, the process has higher requirements on used equipment, furthermore, Chinese patent 201210181617.9 discloses a preparation method of ethyl acetate, by preparing a mesoporous material doped with different metal zirconium contents, the ionic liquid of imidazoles passes through a chemical bond and a mesoporous material surface and a mesoporous material loading method, and H is carried on the mesoporous material2SO4The mesoporous solid super acid composite acidic ionic liquid catalyst is prepared by exchange, has the advantages of high activity, high selectivity and the like for the esterification reaction of acetic acid and ethanol at a lower temperature, and is acidic, so that the ionic liquid has great damage to equipment and is easy to pollute the environment.
Disclosure of Invention
Therefore, it is necessary to provide a method for preparing ethyl acetate by catalytic esterification, aiming at the problems that the existing method is easy to corrode and damage equipment, has high toxicity and is easy to pollute the environment.
In order to solve the problems, the invention provides a method for preparing ethyl acetate by catalytic esterification, which comprises the following steps:
(1) the anion is ArSO3 -、BF4 -And HSO4 -The cation is [ NR ]4]+Benzimidazole cation or imidazo [1,2-a ]]Adding ionic liquid of pyridine cation and ethanol into a reaction container together, whereinR4Is an alkyl group;
(2) stirring the ionic solution in the reaction container in the step (1), dripping acetic acid into the ionic solution, heating to 60-120 ℃ after dripping, and continuously reacting for 2-12 h;
(3) after the reaction is finished, the organic phase is separated from the ionic liquid, the esterification yield is determined after the organic phase is washed, and the moisture in the ionic liquid is removed and then is recycled.
In one embodiment, the ionic liquid has a general structural formula:
r, R therein1、R2Is alkyl, X-Is ArSO3 -、BF4 -And HSO4 -。
In one embodiment, the ionic liquid is prepared as follows:
(1) adding sodium p-toluenesulfonate into an acetonitrile solution in which benzimidazole onium bromide is dissolved to obtain a mixture;
(2) the mixture was refluxed at 80 ℃ overnight;
(3) acetonitrile was evaporated on a rotary evaporator, the concentrated product was dissolved in dichloromethane, filtered to remove unreacted solids and dried under vacuum overnight to give pure ionic liquid.
In one embodiment, the ionic liquid has a general structural formula:
r, R therein3Is alkyl, X-Is ArSO3 -、BF4 -And HSO4 -。
In one embodiment, the ionic liquid is prepared as follows:
(1) dissolving one of bromoethane, bromopropane, bromobutane, bromohexane, bromooctane or benzyl bromide and imidazo [1,2-a ] pyridine in acetonitrile, and heating and refluxing under the protection of nitrogen overnight;
(2) the reaction mixture was cooled to room temperature, the solvent was completely removed in vacuo to give a tan solid, which was dried in a vacuum desiccator overnight;
(3) dissolving the product in acetonitrile, adding sodium p-toluenesulfonate, and refluxing the mixture at 80 deg.C overnight;
(4) acetonitrile was evaporated on a rotary evaporator, the concentrated product was dissolved in dichloromethane, filtered to remove unreacted solids and dried under vacuum overnight to give pure ionic liquid.
In one embodiment, the ionic liquid has a general structural formula:
r, R therein4Is alkyl, X-Is ArSO3 -、BF4 -And HSO4 -。
In one embodiment, the ionic liquid is prepared as follows:
(1) dissolving triethylamine alkyl bromide salt in acetonitrile, and adding sodium p-toluenesulfonate to obtain a mixture;
(2) the mixture was refluxed at 80 ℃ overnight;
(3) the acetonitrile was evaporated on a rotary evaporator, the concentrated product was dissolved in dichloromethane, filtered to remove unreacted solids and dried under vacuum overnight to give the corresponding ionic liquid.
The alkyl is propyl, butyl, hexyl, octyl or benzyl.
In one embodiment, in the step (3), the organic phase is washed with a saturated sodium carbonate solution and a saturated brine; and removing water in the ionic liquid by adopting a vacuum drying method.
In one embodiment, in the step (2), after the acetic acid is added, the temperature is raised to 80-100 ℃, and the reaction is continued for 3-4 h.
In one embodiment, the molar ratio of ethanol to acetic acid is 2: 1; the molar ratio of the ionic liquid to acetic acid is 1: 10.
the technical scheme at least has the following beneficial technical effects:
(1) according to the invention, acetic acid and ethanol are used as reactants, and ionic liquid with anions of aryl sulfonic acid, boron tetrafluoride and hydrogen sulfate is used as a catalyst, so that the yield of ethyl acetate is high, the ionic liquid can be recycled after being recovered, and the activity is not obviously reduced after the ionic liquid is extracted and recovered for removing moisture and is reused for 5 times.
(2) The preparation method of the ethyl acetate is simple, and the price of raw materials and the preparation cost are low; the used equipment is simple, and the equipment used in the preparation process of the ethyl acetate cannot be corroded; toxic substances are not generated in the preparation processes of the ionic liquid and the ethyl acetate, so that the method is a green and efficient method for producing the ethyl acetate, and has good industrial application prospects.
Detailed Description
In order that the invention may be more fully understood, reference will now be made to the accompanying examples. The following is a description of preferred embodiments of the invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Those of ordinary skill in the art will recognize that variations and modifications of the various embodiments described herein can be made without departing from the scope of the invention, which is defined by the appended claims. Moreover, descriptions of well-known functions and constructions may be omitted for clarity and conciseness.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
Example 1:
1, 3-diethylbenzimidazole p-toluenesulfonic acid ionic liquid as catalyst
A50 mL three-necked flask was charged with 5g of acetic acid, 7.7g of ethanol and 2.9g of an ionic liquid, and reacted at 60 ℃ under reflux for 12 hours. Before reaction, the ionic liquid is mixed with ethanol and acetic acid in sequence for mutual dissolution, and after the reaction is finished, the layers are separated. After the reaction solution was cooled to room temperature (25 ℃), the transparent liquid (organic phase) on the upper layer of the reacted mixture was aspirated by a pipette, washed with a saturated sodium carbonate solution and a saturated saline solution, and weighed to determine the ethyl acetate yield of 46%; and simultaneously weighing the lower layer of the mixture after reaction, removing water in the ionic liquid by vacuum rotary evaporation, weighing, comparing the mass change and recovering the ionic liquid.
Example 2:
1-butyl-3-ethylbenzimidazole p-toluenesulfonic acid ionic liquid as catalyst
A50 mL three-necked flask was charged with 5g of acetic acid, 7.7g of ethanol and 3.1g of an ionic liquid, and reacted at 60 ℃ under reflux for 12 hours. Before reaction, the ionic liquid is mixed with ethanol and acetic acid in sequence for mutual dissolution, and after the reaction is finished, the layers are separated. Cooling the reaction solution to room temperature, sucking out the transparent liquid on the upper layer of the reacted mixture by using a suction pipe, washing the transparent liquid by using a saturated sodium carbonate solution and a saturated saline solution, weighing, and measuring the yield of the ethyl acetate to be 50%; and simultaneously weighing the lower layer of the mixture after reaction, removing water in the ionic liquid by vacuum rotary evaporation, weighing, comparing the mass change and recovering the ionic liquid.
Example 3:
1-hexyl-3-ethylbenzimidazole p-toluenesulfonic acid ionic liquid as catalyst
A50 mL three-necked flask was charged with 5g of acetic acid, 7.7g of ethanol and 3.3g of an ionic liquid, and reacted at 60 ℃ under reflux for 12 hours. Before reaction, the ionic liquid is mixed with ethanol and acetic acid in sequence for mutual dissolution, and after the reaction is finished, the layers are separated. After the reaction solution is cooled to room temperature, sucking out the transparent liquid on the upper layer of the reacted mixture by using a suction pipe, washing the transparent liquid by using saturated sodium carbonate solution and saturated saline solution, weighing, and measuring the yield of ethyl acetate to be 53%; and simultaneously weighing the lower layer of the mixture after reaction, removing water in the ionic liquid by vacuum rotary evaporation, weighing, comparing the mass change and recovering the ionic liquid.
Example 4:
1-octyl-3-ethylbenzimidazole p-toluenesulfonic acid ionic liquid as catalyst
A50 mL three-necked flask was charged with 5g of acetic acid, 7.7g of ethanol and 3.5g of an ionic liquid, and reacted at 60 ℃ under reflux for 12 hours. Before reaction, the ionic liquid is mixed with ethanol and acetic acid in sequence for mutual dissolution, and after the reaction is finished, the layers are separated. After the reaction solution was cooled to room temperature, the transparent upper layer liquid of the reacted mixture was sucked out with a pipette, washed with a saturated sodium carbonate solution and a saturated saline solution, and weighed to obtain a yield of ethyl acetate of 59%; and simultaneously weighing the lower layer of the mixture after reaction, removing water in the ionic liquid by vacuum rotary evaporation, weighing, comparing the mass change and recovering the ionic liquid.
Example 5:
1-butyl-3-ethylbenzimidazole p-toluenesulfonic acid ionic liquid as catalyst
A50 mL three-necked flask was charged with 5g of acetic acid, 7.7g of ethanol and 3.8g of an ionic liquid, and reacted at 60 ℃ under reflux for 12 hours. Before reaction, the ionic liquid is mixed with ethanol and acetic acid in sequence for mutual dissolution, and after the reaction is finished, the layers are separated. Cooling the reaction liquid to room temperature, sucking out the transparent liquid on the upper layer of the reacted mixture by using a suction pipe, washing the transparent liquid by using a saturated sodium carbonate solution and a saturated saline solution, weighing, and measuring the yield of the ethyl acetate to be 60%; and simultaneously weighing the lower layer of the mixture after reaction, removing water in the ionic liquid by vacuum rotary evaporation, weighing, comparing the mass change and recovering the ionic liquid.
Example 6:
1-benzyl-3-ethylbenzimidazole p-toluenesulfonic acid ionic liquid as catalyst
A50 mL three-necked flask was charged with 5g of acetic acid, 7.7g of ethanol and 3.4g of an ionic liquid, and reacted at 80 ℃ under reflux for 4 hours. Before reaction, the ionic liquid is mixed with ethanol and acetic acid in sequence for mutual dissolution, and after the reaction is finished, the layers are separated. Cooling the reaction liquid to room temperature, sucking out the transparent liquid on the upper layer of the reacted mixture by using a suction pipe, washing the transparent liquid by using a saturated sodium carbonate solution and a saturated saline solution, weighing, and measuring the yield of the ethyl acetate to be 60%; and simultaneously weighing the lower layer of the mixture after reaction, removing water in the ionic liquid by vacuum rotary evaporation, weighing, comparing the mass change and recovering the ionic liquid.
Example 7:
1-butyl-3-ethylbenzimidazole p-toluenesulfonic acid ionic liquid as catalyst
A50 mL three-necked flask was charged with 5g of acetic acid, 7.7g of ethanol and 3.1g of an ionic liquid, and reacted at 100 ℃ under reflux for 3 hours. Before reaction, the ionic liquid is mixed with ethanol and acetic acid in sequence for mutual dissolution, and after the reaction is finished, the layers are separated. After the reaction liquid is cooled to room temperature, sucking out the transparent liquid on the upper layer of the reacted mixture by using a suction pipe, washing the transparent liquid by using saturated sodium carbonate solution and saturated saline solution, weighing, and measuring the yield of the ethyl acetate to be 70%; and simultaneously weighing the lower layer of the mixture after reaction, removing water in the ionic liquid by vacuum rotary evaporation, weighing, comparing the mass change and recovering the ionic liquid.
Example 8:
1-ethylimidazo [1,2-a ] pyridine p-toluenesulfonic acid ionic liquid as catalyst
A50 mL three-necked flask was charged with 5g of acetic acid, 7.7g of ethanol and 2.7g of an ionic liquid, and reacted at 80 ℃ under reflux for 4 hours. Before reaction, the ionic liquid is mixed with ethanol and acetic acid in sequence for mutual dissolution, and after the reaction is finished, the layers are separated. After the reaction liquid is cooled to room temperature, sucking out the transparent liquid on the upper layer of the reacted mixture by using a suction pipe, washing the transparent liquid by using saturated sodium carbonate solution and saturated saline solution, weighing, and measuring the yield of the ethyl acetate to be 75%; and simultaneously weighing the lower layer of the mixture after reaction, removing water in the ionic liquid by vacuum rotary evaporation, weighing, comparing the mass change and recovering the ionic liquid.
Example 9:
1-propylimidazo [1,2-a ] pyridine p-toluenesulfonic acid ionic liquid as catalyst
A50 mL three-necked flask was charged with 5g of acetic acid, 7.7g of ethanol and 2.8g of an ionic liquid, and reacted at 80 ℃ under reflux for 4 hours. Before reaction, the ionic liquid is mixed with ethanol and acetic acid in sequence for mutual dissolution, and after the reaction is finished, the layers are separated. After the reaction solution is cooled to room temperature, sucking out the transparent liquid on the upper layer of the reacted mixture by using a suction pipe, washing the transparent liquid by using saturated sodium carbonate solution and saturated saline solution, weighing, and measuring the yield of ethyl acetate to be 68%; and simultaneously weighing the lower layer of the mixture after reaction, removing water in the ionic liquid by vacuum rotary evaporation, weighing, comparing the mass change and recovering the ionic liquid.
Example 10:
1-butylimidazo [1,2-a ] pyridine p-toluenesulfonic acid ionic liquid as catalyst
A50 mL three-necked flask was charged with 5g of acetic acid, 7.7g of ethanol and 2.9g of an ionic liquid, and reacted at 80 ℃ under reflux for 4 hours. Before reaction, the ionic liquid is mixed with ethanol and acetic acid in sequence for mutual dissolution, and after the reaction is finished, the layers are separated. After the reaction liquid is cooled to room temperature, sucking out the transparent liquid on the upper layer of the reacted mixture by using a suction pipe, washing the transparent liquid by using saturated sodium carbonate solution and saturated saline solution, weighing, and measuring the yield of the ethyl acetate to be 75%; and simultaneously weighing the lower layer of the mixture after reaction, removing water in the ionic liquid by vacuum rotary evaporation, weighing, comparing the mass change and recovering the ionic liquid.
Example 11:
1-octyl imidazo [1,2-a ] pyridine p-toluenesulfonic acid ionic liquid as catalyst
A50 mL three-necked flask was charged with 5g of acetic acid, 7.7g of ethanol and 3.1g of an ionic liquid, and reacted at 80 ℃ under reflux for 4 hours. Before reaction, the ionic liquid is mixed with ethanol and acetic acid in sequence for mutual dissolution, and after the reaction is finished, the layers are separated. After the reaction solution is cooled to room temperature, sucking out the transparent liquid on the upper layer of the reacted mixture by using a suction pipe, washing the transparent liquid by using saturated sodium carbonate solution and saturated saline solution, weighing, and measuring the yield of ethyl acetate to be 73%; and simultaneously weighing the lower layer of the mixture after reaction, removing water in the ionic liquid by vacuum rotary evaporation, weighing, comparing the mass change and recovering the ionic liquid.
Example 12:
1-benzyl imidazo [1,2-a ] pyridine p-toluenesulfonic acid ionic liquid as catalyst
A50 mL three-necked flask was charged with 5g of acetic acid, 7.7g of ethanol and 3.2g of an ionic liquid, and reacted at 80 ℃ under reflux for 4 hours. Before reaction, the ionic liquid is mixed with ethanol and acetic acid in sequence for mutual dissolution, and after the reaction is finished, the layers are separated. After the reaction liquid is cooled to room temperature, sucking out the transparent liquid on the upper layer of the reacted mixture by using a suction pipe, washing the transparent liquid by using saturated sodium carbonate solution and saturated saline solution, weighing, and measuring the yield of ethyl acetate to be 72%; and simultaneously weighing the lower layer of the mixture after reaction, removing water in the ionic liquid by vacuum rotary evaporation, weighing, comparing the mass change and recovering the ionic liquid.
Example 13:
1-butylimidazo [1,2-a ] pyridine p-toluenesulfonic acid ionic liquid as catalyst
A50 mL three-necked flask was charged with 5g of acetic acid, 7.7g of ethanol and 2.9g of an ionic liquid, and reacted at 100 ℃ under reflux for 3 hours. Before reaction, the ionic liquid is mixed with ethanol and acetic acid in sequence for mutual dissolution, and after the reaction is finished, the layers are separated. After the reaction liquid is cooled to room temperature, sucking out the transparent liquid on the upper layer of the reacted mixture by using a suction pipe, washing the transparent liquid by using saturated sodium carbonate solution and saturated saline solution, weighing, and measuring the yield of ethyl acetate to be 72%; and simultaneously weighing the lower layer of the mixture after reaction, removing water in the ionic liquid by vacuum rotary evaporation, weighing, comparing the mass change and recovering the ionic liquid.
Example 14:
1-butylimidazo [1,2-a ] pyridine p-toluenesulfonic acid ionic liquid as catalyst
A50 mL three-necked flask was charged with 5g of acetic acid, 7.7g of ethanol and 2.9g of an ionic liquid, and reacted at 120 ℃ under reflux for 2 hours. Before reaction, the ionic liquid is mixed with ethanol and acetic acid in sequence for mutual dissolution, and after the reaction is finished, the layers are separated. After the reaction liquid is cooled to room temperature, sucking out the transparent liquid on the upper layer of the reacted mixture by using a suction pipe, washing the transparent liquid by using saturated sodium carbonate solution and saturated saline solution, weighing, and measuring the yield of the ethyl acetate to be 76%; and simultaneously weighing the lower layer of the mixture after reaction, removing water in the ionic liquid by vacuum rotary evaporation, weighing, comparing the mass change and recovering the ionic liquid.
Example 15:
triethylbutylammonium p-toluenesulfonic acid ionic liquid as catalyst
A50 mL three-necked flask was charged with 5g of acetic acid, 7.7g of ethanol and 2.7g of an ionic liquid, and reacted at 60 ℃ under reflux for 12 hours. Before reaction, the ionic liquid is mixed with ethanol and acetic acid in sequence for mutual dissolution, and after the reaction is finished, the layers are separated. After the reaction solution is cooled to room temperature, sucking out the transparent liquid on the upper layer of the reacted mixture by using a suction pipe, washing the transparent liquid by using saturated sodium carbonate solution and saturated saline solution, weighing, and measuring the yield of the ethyl acetate to be 55%; and simultaneously weighing the lower layer of the mixture after reaction, removing water in the ionic liquid by vacuum rotary evaporation, weighing, comparing the mass change and recovering the ionic liquid.
Example 16:
triethylbutylammonium p-toluenesulfonic acid ionic liquid as catalyst
A50 mL three-necked flask was charged with 5g of acetic acid, 7.7g of ethanol and 2.7g of an ionic liquid, and reacted at 90 ℃ under reflux for 4 hours. Before reaction, the ionic liquid is mixed with ethanol and acetic acid in sequence for mutual dissolution, and after the reaction is finished, the layers are separated. After the reaction solution is cooled to room temperature, sucking out the transparent liquid on the upper layer of the reacted mixture by using a suction pipe, washing the transparent liquid by using saturated sodium carbonate solution and saturated saline solution, weighing, and measuring the yield of ethyl acetate to be 68%; and simultaneously weighing the lower layer of the mixture after reaction, removing water in the ionic liquid by vacuum rotary evaporation, weighing, comparing the mass change and recovering the ionic liquid.
Example 17:
triethylbutylammonium p-toluenesulfonic acid ionic liquid as catalyst
A50 mL three-necked flask was charged with 5g of acetic acid, 7.7g of ethanol and 2.7g of an ionic liquid, and reacted at 120 ℃ under reflux for 2 hours. Before reaction, the ionic liquid is mixed with ethanol and acetic acid in sequence for mutual dissolution, and after the reaction is finished, the layers are separated. After the reaction solution is cooled to room temperature, sucking out the transparent liquid on the upper layer of the reacted mixture by using a suction pipe, washing the transparent liquid by using saturated sodium carbonate solution and saturated saline solution, weighing, and measuring the yield of ethyl acetate to be 73%; and simultaneously weighing the lower layer of the mixture after reaction, removing water in the ionic liquid by vacuum rotary evaporation, weighing, comparing the mass change and recovering the ionic liquid.
Example 18:
triethylammonium p-toluenesulfonic acid ionic liquid as catalyst
A50 mL three-necked flask was charged with 5g of acetic acid, 7.7g of ethanol and 2.6g of an ionic liquid, and reacted at 120 ℃ under reflux for 2 hours. Before reaction, the ionic liquid is mixed with ethanol and acetic acid in sequence for mutual dissolution, and after the reaction is finished, the layers are separated. After the reaction liquid is cooled to room temperature, sucking out the transparent liquid on the upper layer of the reacted mixture by using a suction pipe, washing the transparent liquid by using saturated sodium carbonate solution and saturated saline solution, weighing, and measuring the yield of the ethyl acetate to be 70%; and simultaneously weighing the lower layer of the mixture after reaction, removing water in the ionic liquid by vacuum rotary evaporation, weighing, comparing the mass change and recovering the ionic liquid.
Example 19:
triethylhexylammonium p-toluenesulfonic acid ionic liquid as catalyst
A50 mL three-necked flask was charged with 5g of acetic acid, 7.7g of ethanol and 2.9g of an ionic liquid, and reacted at 120 ℃ under reflux for 2 hours. Before reaction, the ionic liquid is mixed with ethanol and acetic acid in sequence for mutual dissolution, and after the reaction is finished, the layers are separated. After the reaction solution is cooled to room temperature, sucking out the transparent liquid on the upper layer of the reacted mixture by using a suction pipe, washing the transparent liquid by using saturated sodium carbonate solution and saturated saline solution, weighing, and measuring the yield of the ethyl acetate to be 65%; and simultaneously weighing the lower layer of the mixture after reaction, removing water in the ionic liquid by vacuum rotary evaporation, weighing, comparing the mass change and recovering the ionic liquid.
Example 20:
triethyloctylammonium p-toluenesulfonic acid ionic liquid as catalyst
A50 mL three-necked flask was charged with 5g of acetic acid, 7.7g of ethanol and 3.2g of an ionic liquid, and reacted at 120 ℃ under reflux for 2 hours. Before reaction, the ionic liquid is mixed with ethanol and acetic acid in sequence for mutual dissolution, and after the reaction is finished, the layers are separated. After the reaction liquid is cooled to room temperature, sucking out the transparent liquid on the upper layer of the reacted mixture by using a suction pipe, washing the transparent liquid by using saturated sodium carbonate solution and saturated saline solution, weighing, and measuring the yield of the ethyl acetate to be 63%; and simultaneously weighing the lower layer of the mixture after reaction, removing water in the ionic liquid by vacuum rotary evaporation, weighing, comparing the mass change and recovering the ionic liquid.
Example 21:
triethylammonium p-toluenesulfonic acid ionic liquid as catalyst
A50 mL three-necked flask was charged with 5g of acetic acid, 7.7g of ethanol and 3.2g of an ionic liquid, and reacted at 120 ℃ under reflux for 2 hours. Before reaction, the ionic liquid is mixed with ethanol and acetic acid in sequence for mutual dissolution, and after the reaction is finished, the layers are separated. After the reaction liquid is cooled to room temperature, sucking out the transparent liquid on the upper layer of the reacted mixture by using a suction pipe, washing the transparent liquid by using saturated sodium carbonate solution and saturated saline solution, weighing, and measuring the yield of the ethyl acetate to be 70%; and simultaneously weighing the lower layer of the mixture after reaction, removing water in the ionic liquid by vacuum rotary evaporation, weighing, comparing the mass change and recovering the ionic liquid.
In examples 1 to 7, the ion solution preparation method used was:
preparation of benzimidazolium bromide according to the literature (synthesis of ionic liquids of the type benzimidazole and application studies in esterification [ J ]. proceedings of the college of jujube village, 2017 (2)), on the basis of which an ionic liquid was prepared, sodium p-toluenesulfonate (2.4mmol) was added to an acetonitrile solution in which benzimidazolium bromide (2.0mmol) was dissolved to give a mixture;
the mixture was refluxed at 80 ℃ overnight;
the acetonitrile was evaporated on a rotary evaporator, the concentrated product was taken up in dichloromethane solvent to remove excess unreacted solid and dried under vacuum overnight to give the corresponding ionic liquid.
The ionic solutions used in examples 8-14 above were prepared as follows:
imidazo [1,2-a ] pyridine (2mmol) and bromoethane (bromopropane, bromobutane, bromohexane, bromooctane or benzyl bromide) (4mmol) were dissolved in acetonitrile (50mL) and heated under reflux overnight under nitrogen;
the reaction mixture was cooled to room temperature, the solvent was completely removed in vacuo to give a tan solid, which was dried in a vacuum desiccator overnight;
the product (2.0mmol) was dissolved in acetonitrile, sodium p-toluenesulfonate (2.4mmol) was added and the mixture was refluxed at 80 ℃ overnight;
the acetonitrile was evaporated on a rotary evaporator, the concentrated product was taken up in dichloromethane solvent to remove excess unreacted solid and dried under vacuum overnight to give the corresponding ionic liquid.
In the above examples 15 to 21, the ionic solutions used were prepared as follows:
triethylamine alkyl (benzyl) bromide was synthesized according to the literature (Hog M, Schneider M, Krossing I.Synthesis and Characterizationo f Bromoaluminate Ionic Liquids [ J ]. Chemistry-A European Journal,2017,23(41):9821-9830.) Triethylamine (benzyl) bromide (2.0mmol) was dissolved in acetonitrile and sodium p-toluenesulfonate (2.4mmol) was added to give a mixture;
the mixture was refluxed at 80 ℃ overnight;
the acetonitrile was evaporated on a rotary evaporator, the concentrated product was taken up in dichloromethane solvent to remove excess unreacted solid and dried under vacuum overnight to give the corresponding ionic liquid.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. The method for preparing ethyl acetate by catalytic esterification is characterized by comprising the following steps:
(1) the anion is ArSO3 -、BF4 -And HSO4 -The cation is [ NR ]4]+Benzimidazole cation or imidazo [1,2-a ]]Adding ionic liquid of pyridine cation and ethanol into a reaction container together, wherein R4Is an alkyl group;
(2) stirring the ionic solution in the reaction container in the step (1), dripping acetic acid into the ionic solution, heating to 60-120 ℃ after dripping, and continuously reacting for 2-12 h;
(3) after the reaction is finished, the organic phase is separated from the ionic liquid, the esterification yield is determined after the organic phase is washed, and the moisture in the ionic liquid is removed and then is recycled.
2. The method for preparing ethyl acetate through catalytic esterification according to claim 1, wherein the ionic liquid has a general structural formula:
r, R therein1、R2Is alkyl, X-Is ArSO3 -、BF4 -And HSO4 -。
3. The method for preparing ethyl acetate by catalytic esterification according to claim 2, wherein the ionic liquid is prepared by the following method:
(1) adding sodium p-toluenesulfonate into an acetonitrile solution in which benzimidazole onium bromide is dissolved to obtain a mixture;
(2) the mixture was refluxed at 80 ℃ overnight;
(3) the acetonitrile was evaporated on a rotary evaporator, the concentrated product was dissolved in dichloromethane, filtered to remove unreacted solid, and dried under vacuum overnight to give pure ionic liquid.
4. The method for preparing ethyl acetate through catalytic esterification according to claim 1, wherein the ionic liquid has a general structural formula:
r, R therein3Is alkyl, X-Is ArSO3 -、BF4 -And HSO4 -。
5. The method for preparing ethyl acetate by catalytic esterification according to claim 4, wherein the ionic liquid is prepared by the following method:
(1) dissolving one of bromoethane, bromopropane, bromobutane, bromohexane, bromooctane or benzyl bromide and imidazo [1,2-a ] pyridine in acetonitrile, and heating and refluxing under the protection of nitrogen overnight;
(2) the reaction mixture was cooled to room temperature, the solvent was completely removed in vacuo to give a tan solid, which was dried in a vacuum desiccator overnight;
(3) dissolving the product in acetonitrile, adding sodium p-toluenesulfonate, and refluxing the mixture at 80 deg.C overnight;
(4) acetonitrile was evaporated on a rotary evaporator, the concentrated product was dissolved in dichloromethane, filtered to remove unreacted solids, and dried under vacuum overnight to give pure ionic liquid.
6. The method for preparing ethyl acetate through catalytic esterification according to claim 1, wherein the ionic liquid has a general structural formula:r, R therein4Is alkyl, X-Is ArSO3 -、BF4 -And HSO4 -。
7. The method for preparing ethyl acetate by catalytic esterification according to claim 6, wherein the ionic liquid is prepared by the following method:
(1) dissolving triethylamine alkyl bromide salt in acetonitrile, and adding sodium p-toluenesulfonate to obtain a mixture;
(2) the mixture was refluxed at 80 ℃ overnight;
(3) acetonitrile was evaporated on a rotary evaporator, the concentrated product was dissolved in dichloromethane, filtered to remove unreacted solids, and dried under vacuum overnight to give pure ionic liquid.
8. The process for preparing ethyl acetate by catalytic esterification according to claim 1, wherein, in the step (3), the organic phase is washed with a saturated sodium carbonate solution and a saturated brine; and removing water in the ionic liquid by adopting a vacuum drying method.
9. The method for preparing ethyl acetate through catalytic esterification according to claim 1, wherein in the step (2), after the acetic acid is added, the temperature is raised to 80-100 ℃, and the reaction is continued for 3-4 hours.
10. The catalytic esterification process for preparing ethyl acetate according to claim 1, wherein the molar ratio of ethanol to acetic acid is 2: 1; the molar ratio of the ionic liquid to acetic acid is 1: 10.
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| CN112409354A (en) * | 2020-12-23 | 2021-02-26 | 苏利制药科技江阴有限公司 | Synthesis process of 7-fluoroimidazo [1,2-A ] pyridine and intermediate thereof |
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| CN113813995A (en) * | 2021-10-28 | 2021-12-21 | 兖矿水煤浆气化及煤化工国家工程研究中心有限公司 | Ionic liquid catalyst for catalytic synthesis of methyl acetate, application thereof and method for catalytic synthesis of methyl acetate |
| CN115260034A (en) * | 2021-12-13 | 2022-11-01 | 江苏索普化工股份有限公司 | Original start-up and stop method for producing ethyl acetate by using industrial ionic liquid catalyst |
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| CN112409354A (en) * | 2020-12-23 | 2021-02-26 | 苏利制药科技江阴有限公司 | Synthesis process of 7-fluoroimidazo [1,2-A ] pyridine and intermediate thereof |
| CN112409354B (en) * | 2020-12-23 | 2021-10-08 | 苏利制药科技江阴有限公司 | Synthesis process of 7-fluoroimidazo [1,2-A ] pyridine and intermediate thereof |
| CN113813994A (en) * | 2021-10-28 | 2021-12-21 | 兖矿水煤浆气化及煤化工国家工程研究中心有限公司 | Ionic liquid catalyst for catalytic synthesis of ethyl acetate, application of ionic liquid catalyst and method for catalytic synthesis of ethyl acetate |
| CN113813995A (en) * | 2021-10-28 | 2021-12-21 | 兖矿水煤浆气化及煤化工国家工程研究中心有限公司 | Ionic liquid catalyst for catalytic synthesis of methyl acetate, application thereof and method for catalytic synthesis of methyl acetate |
| CN113813995B (en) * | 2021-10-28 | 2023-10-20 | 兖矿水煤浆气化及煤化工国家工程研究中心有限公司 | Ionic liquid catalyst for catalytic synthesis of methyl acetate, application of ionic liquid catalyst and method for catalytic synthesis of methyl acetate |
| CN113813994B (en) * | 2021-10-28 | 2023-10-20 | 兖矿水煤浆气化及煤化工国家工程研究中心有限公司 | Ionic liquid catalyst for catalytic synthesis of ethyl acetate, application of ionic liquid catalyst and method for catalytic synthesis of ethyl acetate |
| CN115260034A (en) * | 2021-12-13 | 2022-11-01 | 江苏索普化工股份有限公司 | Original start-up and stop method for producing ethyl acetate by using industrial ionic liquid catalyst |
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