阅读说明：本技术 一种呋喃酮的合成方法 (Synthetic method of furanone ) 是由 陈清 于 2021-10-21 设计创作，主要内容包括：本发明公开了一种呋喃酮的合成方法,具体涉及呋喃酮合成技术领域,包括以下具体步骤：步骤一、准备工具：将三口烧瓶放入水浴加热箱中,然后在三口烧瓶的其中一个口中插入温度计,再在中间的口中插入自动搅拌装置,再在剩下的一个开口中插入漏斗,步骤二、制备偶联物,步骤三、制备呋喃酮。本发明通过利用正丁醇和石油醚的混合溶液代替传统工艺中的乙酸乙酯溶液,以提高3,4-二羟基-2,5-已二酮的溶解度,从而能够提高萃取后3,4-二羟基-2,5-已二酮的产量,在制备偶联物的过程中向水浴箱中及时添加冰块,维持水浴箱的温度在25～40℃的范围内,以吸收锌粉在化学反应过程中发出的热量,进而防止反应体系温度上升到变质温度而影响最终的产物,以保证呋喃酮的产量。(The invention discloses a method for synthesizing furanone, which particularly relates to the technical field of furanone synthesis and comprises the following specific steps: step one, preparing a tool: putting the three-neck flask into a water-bath heating box, inserting a thermometer into one of the three-neck flask, inserting an automatic stirring device into the middle neck, inserting a funnel into the other opening, preparing the conjugate, and preparing the furanone. According to the invention, the mixed solution of n-butyl alcohol and petroleum ether is used for replacing an ethyl acetate solution in the traditional process to improve the solubility of 3, 4-dihydroxy-2, 5-hexanedione, so that the yield of the extracted 3, 4-dihydroxy-2, 5-hexanedione can be improved, ice blocks are added into a water bath box in time in the process of preparing the conjugate, the temperature of the water bath box is maintained within the range of 25-40 ℃, the heat generated by zinc powder in the chemical reaction process is absorbed, and the final product is prevented from being influenced by the temperature of a reaction system rising to the deterioration temperature, so that the yield of furanone is ensured.)

1. A synthetic method of furanone is characterized in that: the method comprises the following specific steps:

step one, preparing a tool: putting the three-neck flask into a water-bath heating box, then inserting a thermometer into one of the three-neck flask, inserting an automatic stirring device into the middle neck, and inserting a funnel into the remaining opening for adding raw materials for synthesis reaction;

step two, preparing a conjugate: s1, sequentially adding 20g of methylglyoxal and 20ml of acetic acid into a three-neck flask from a funnel, starting an automatic stirring device, maintaining the temperature of a water bath box within the range of 25-40 ℃, adding 4g of zinc powder into the three-neck flask through the funnel after 15 minutes, adding 4g of zinc powder into the three-neck flask every 15 minutes, adding 16g of zinc powder into the three-neck flask in total, releasing heat during the adding process of the zinc powder, adding ice blocks into the water bath box at the moment, and maintaining the temperature of the water bath box within the range of 25-40 ℃; s2, after the zinc powder is added, continuously keeping the temperature of the water bath box within the range of 25-40 ℃, and stirring for reacting for 1.5 hours; s3, after the reaction is finished, filtering under reduced pressure to remove excessive zinc powder and part of saturated and precipitated zinc acetate, evaporating the filtrate under reduced pressure to dryness of the aqueous solution on a rotary evaporator at a temperature lower than 55 ℃, leaching twice with 80mL of ethyl acetate, filtering to remove zinc acetate crystals, drying the filtrate, distilling at normal pressure to recover the ethyl acetate solvent, and obtaining 19g of light yellow oily viscous liquid; s4, adding a mixed solution of 20mL of n-butanol and 16mL of petroleum ether into the yellowish oily viscous liquid, crystallizing at a low temperature of-5-0 ℃, filtering and drying to obtain 9.4g of threo-3, 4-dihydroxy-2, 5-hexanedione; s5, decompressing the filtrate after the threo-type 3, 4-dihydroxy-2, 5-hexanedione is separated, removing the solvent to obtain yellow oily liquid, adding a mixed solution of chloroform and petroleum ether, adding the erythro-type 3, 4-dihydroxy-2, 5-hexanedione as a seed crystal, crystallizing at low temperature, and filtering to obtain the erythro-type 3, 4-dihydroxy-2, 5-hexanedione;

step three, preparing furanone: adding 10ml of Na2HPO4 aqueous solution into the prepared conjugate, reacting for 24 hours at a certain temperature, adding acetic acid into the solution to adjust the pH value of the solution, standing and cooling the reacted solution at normal temperature, extracting, drying, filtering and concentrating the cooled solution in sequence to obtain a crude product of red oily matter, and then purifying and crystallizing the crude product to obtain the crystal furanone.

2. The method for synthesizing furanone according to claim 1, wherein the method comprises the following steps: and in the second step, stirring the excessive filtered zinc powder for 1-3 minutes by using 1-2% dilute hydrochloric acid, filtering, and washing a filter cake by using water, ethanol and diethyl ether in sequence to obtain the dried and activated zinc powder.

3. The method for synthesizing furanone according to claim 1, wherein the method comprises the following steps: in the second step, 80mL of ethyl acetate is leached twice, the dosage of the first ethyl acetate is 50mL, the dosage of the second ethyl acetate is 30mL, and the leaching temperature is controlled within the range of 35-40 ℃.

4. The method for synthesizing furanone according to claim 1, wherein the method comprises the following steps: the melting point of threo-3, 4-dihydroxy-2, 5-hexanedione prepared in the second step is 90 deg.c, and the melting point of erythro-3, 4-dihydroxy-2, 5-hexanedione prepared in the second step is 60 deg.c.

5. The method for synthesizing furanone according to claim 1, wherein the method comprises the following steps: the conjugate in the second step comprises threo 3, 4-dihydroxy-2, 5-hexanedione and erythro 3, 4-dihydroxy-2, 5-hexanedione, wherein threo 3, 4-dihydroxy-2, 5-hexanedione accounts for 83% of the total amount and erythro 3, 4-dihydroxy-2, 5-hexanedione accounts for 18% of the total amount.

6. The method for synthesizing furanone according to claim 1, wherein the method comprises the following steps: in the third step, after standing for a period of time, separating out an oil phase and a water phase, concentrating the water phase to recover sodium dihydrogen phosphate, returning to the cyclization reaction, and discharging wastewater; and concentrating the oil phase to recover butyl acetate and obtain a liquid-phase crude furanone product.

7. The method for synthesizing furanone according to claim 1, wherein the method comprises the following steps: in the third step, the crude furanone product is subjected to freezing crystallization and centrifugal separation to obtain crude furanone, the crude furanone is dissolved in ethanol and ethyl acetate for extraction, the volume ratio of the ethanol to the ethyl acetate is 1:1.1-8.2, after impurities are filtered out, the crude furanone product is subjected to freezing crystallization and centrifugal separation to obtain a finished furanone product, and the wet furanone product is dried to obtain the finished furanone product.

8. The method for synthesizing furanone according to claim 1, wherein the method comprises the following steps: and (3) drying in the second step and the third step by adopting a vacuum drying oven, wherein the use environment of the vacuum drying oven requires as follows: a. temperature: 5-40 ℃; b. relative humidity: RH is less than or equal to 85 percent; c. power supply voltage: 220V +/-10% and 50 Hz; d. the surrounding is not affected by strong vibration and corrosive gas.

Technical Field

The invention relates to the technical field of furanone synthesis, in particular to a method for synthesizing furanone.

Background

Furanone as "king of flavor" exists in food, tobacco and beverage, and has a significant flavor modifying effect when the flavor threshold is 0.04ppb, so that furanone is widely used as a flavoring agent for food, tobacco and beverage; although furanone is widely present in natural products, it cannot meet daily requirements due to its low content, and most of furanones are synthetic products used in the food industry. The product is mainly produced by Finelyensis corporation (Finenichco.) in the world, and China's Dajinju spice factory first realizes the industrialized production of furanone through continuous efforts at home, and ends the history that the product depends on import for a long time.

However, in the process for producing furanone in the prior art, ethyl lactate is used as a raw material, furanone is prepared through multi-step reactions, methyl bromide is used as an alkylating reagent in the synthesis process, but the methyl bromide used is a substance which seriously consumes the ozone layer and can damage the ozone layer of the earth, in addition, the raw material cost in the process is relatively high, the production cost of furanone can be increased, and if the heat generated in the reaction process is not discharged in time, the temperature of reactants can be increased, so that the reactants are changed in quality, and the yield of furanone can be influenced.

Disclosure of Invention

Therefore, the invention provides a method for synthesizing furanone, which is characterized in that ice blocks are added into a water bath box in time in the process of preparing a conjugate, the temperature of the water bath box is maintained within the range of 25-40 ℃, so that heat generated by zinc powder in the chemical reaction process is absorbed, the temperature of a reaction system is prevented from rising to the deterioration temperature to influence the final product, the yield of the furanone is ensured, and the problems in the background art are solved.

In order to achieve the above object, the embodiments of the present invention provide the following technical solutions: a synthetic method of furanone comprises the following specific steps:

step one, preparing a tool: putting the three-neck flask into a water-bath heating box, then inserting a thermometer into one of the three-neck flask, inserting an automatic stirring device into the middle neck, and inserting a funnel into the remaining opening for adding raw materials for synthesis reaction;

step two, preparing a conjugate: s1, sequentially adding 20g of methylglyoxal and 20ml of acetic acid into a three-neck flask from a funnel, starting an automatic stirring device, maintaining the temperature of a water bath box within the range of 25-40 ℃, adding 4g of zinc powder into the three-neck flask through the funnel after 15 minutes, adding 4g of zinc powder into the three-neck flask every 15 minutes, adding 16g of zinc powder into the three-neck flask in total, releasing heat during the adding process of the zinc powder, adding ice blocks into the water bath box at the moment, and maintaining the temperature of the water bath box within the range of 25-40 ℃; s2, after the zinc powder is added, continuously keeping the temperature of the water bath box within the range of 25-40 ℃, and stirring for reacting for 1.5 hours; s3, after the reaction is finished, filtering under reduced pressure to remove excessive zinc powder and part of saturated and precipitated zinc acetate, evaporating the filtrate under reduced pressure to dryness of the aqueous solution on a rotary evaporator at a temperature lower than 55 ℃, leaching twice with 80mL of ethyl acetate, filtering to remove zinc acetate crystals, drying the filtrate, distilling at normal pressure to recover the ethyl acetate solvent, and obtaining 19g of light yellow oily viscous liquid; s4, adding a mixed solution of 20mL of n-butanol and 16mL of petroleum ether into the yellowish oily viscous liquid, crystallizing at a low temperature of-5-0 ℃, filtering and drying to obtain 9.4g of threo-3, 4-dihydroxy-2, 5-hexanedione; s5, decompressing the filtrate after the threo-type 3, 4-dihydroxy-2, 5-hexanedione is separated, removing the solvent to obtain yellow oily liquid, adding a mixed solution of chloroform and petroleum ether, adding the erythro-type 3, 4-dihydroxy-2, 5-hexanedione as a seed crystal, crystallizing at low temperature, and filtering to obtain the erythro-type 3, 4-dihydroxy-2, 5-hexanedione;

step three, preparing furanone: adding 10ml of Na2HPO4 aqueous solution into the prepared conjugate, reacting for 24 hours at a certain temperature, adding acetic acid into the solution to adjust the pH value of the solution, standing and cooling the reacted solution at normal temperature, extracting, drying, filtering and concentrating the cooled solution in sequence to obtain a crude product of red oily matter, and then purifying and crystallizing the crude product to obtain the crystal furanone.

Further, in the second step, stirring the excessive zinc powder removed by filtering with 1-2% dilute hydrochloric acid for 1-3 minutes, filtering, and washing the filter cake with water, ethanol and diethyl ether in sequence to obtain the dried and activated zinc powder, wherein the recovery of the zinc powder in the reaction process is beneficial to saving resources and reducing the production cost of furanone.

Further, in the second step, in the two leaching processes of 80mL of ethyl acetate, the dosage of the first ethyl acetate is 50mL, the dosage of the second ethyl acetate is 30mL, and the leaching temperature is controlled within the range of 35-40 ℃.

Further, the melting point of threo-type 3, 4-dihydroxy-2, 5-hexanedione prepared in the second step is 90 deg.C, and the melting point of erythro-type 3, 4-dihydroxy-2, 5-hexanedione prepared in the second step is 60 deg.C.

Further, the conjugate in the second step includes threo 3, 4-dihydroxy-2, 5-hexanedione and erythro 3, 4-dihydroxy-2, 5-hexanedione, wherein threo 3, 4-dihydroxy-2, 5-hexanedione accounts for 83% of the total amount and erythro 3, 4-dihydroxy-2, 5-hexanedione accounts for 18% of the total amount.

Further, in the third step, after standing for a period of time, separating out an oil phase and a water phase, recovering sodium dihydrogen phosphate from the water phase through concentration, returning to the cyclization reaction, and discharging wastewater; and concentrating the oil phase to recover butyl acetate and obtain a liquid-phase crude furanone product.

Further, in the third step, the crude furanone product is subjected to freezing crystallization and centrifugal separation to obtain crude furanone, the crude furanone is dissolved in ethanol and ethyl acetate for extraction, the volume ratio of the ethanol to the ethyl acetate is 1:1.1-8.2, after impurities are filtered out, a finished furanone product is obtained through freezing crystallization and centrifugal separation, and the wet furanone product is dried to obtain the finished furanone product.

Further, the drying in the second step and the third step adopts a vacuum drying oven, and the use environment of the vacuum drying oven requires the following steps: a. temperature: 5-40 ℃; b. relative humidity: RH is less than or equal to 85 percent; c. power supply voltage: 220V +/-10% and 50 Hz; d. the surrounding is not affected by strong vibration and corrosive gas.

The invention has the following advantages:

1. the ice blocks are added into the water bath box in time in the process of preparing the conjugate, the temperature of the water bath box is maintained within the range of 25-40 ℃, so that the heat generated by the zinc powder in the chemical reaction process is absorbed, the final product is prevented from being influenced by the temperature of a reaction system rising to the deterioration temperature, and the yield of furanone is ensured;

2. according to the invention, the mixed solution of n-butyl alcohol and petroleum ether is used for replacing an ethyl acetate solution in the traditional process to improve the solubility of 3, 4-dihydroxy-2, 5-hexanedione, so that the yield of the extracted 3, 4-dihydroxy-2, 5-hexanedione can be improved, and the final yield of furanone can be further improved;

3. in the process of preparing the coupling agent, no additional water is added into the three-neck flask, and compared with the prior art, the water distillation amount in the method is obviously reduced, so that the method can effectively shorten the water distillation time in the process of decompressing and distilling water, and can effectively reduce the energy consumption generated in the water distillation process so as to improve the economic benefit of industrial production.

4. The method comprises the steps of separating a filtrate from threo-type 3, 4-dihydroxy-2, 5-hexanedione, removing a solvent to obtain a yellow oily liquid, adding a mixed solution of chloroform and petroleum ether, adding erythro-type 3, 4-dihydroxy-2, 5-hexanedione as a seed crystal, crystallizing at a low temperature, and filtering to obtain erythro-type 3, 4-dihydroxy-2, 5-hexanedione, wherein compared with the method that the filtrate is directly discarded in the prior art, the method can recover the erythro-type 3, 4-dihydroxy-2, 5-hexanedione from the filtrate, and further can improve the total yield of the 3, 4-dihydroxy-2, 5-hexanedione and improve the economic benefit;

5. the reaction process only needs two steps, the reaction yield is high, the cost is low, compared with the method for preparing furanone by using methyl bromide in the prior art, the reaction process is cleaner, methyl bromide gas is not used, the influence on the environment is small, and the method is a green and environment-friendly processing process.

Detailed Description

The present invention is described in terms of particular embodiments, other advantages and features of the invention will become apparent to those skilled in the art from the following disclosure, and it is to be understood that the described embodiments are merely exemplary of the invention and that it is not intended to limit the invention to the particular embodiments disclosed. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The method for synthesizing furanone of the embodiment comprises the following specific steps:

step one, preparing a tool: putting a three-mouth flask (the three-mouth flask usually has the appearance of a round-belly narrow neck, has three mouths, can be simultaneously added with a plurality of reactants, or is provided with a condenser pipe, the narrow mouth of the three-mouth flask is used for preventing the solution from splashing or reducing the evaporation of the solution, and can be matched with a rubber stopper to be connected with other glass devices) into a water bath heating box, then inserting a thermometer into one mouth of the three-mouth flask, inserting an automatic stirring device into the middle mouth, and inserting a funnel into the other opening to add raw materials for synthesis reaction;

step two, preparing a conjugate: s1, sequentially adding 20g of methylglyoxal and 20ml of acetic acid into a three-neck flask from a funnel, starting an automatic stirring device, maintaining the temperature of a water bath box within the range of 25-40 ℃, adding 4g of zinc powder into the three-neck flask through the funnel after 15 minutes, adding 4g of zinc powder into the three-neck flask every 15 minutes, adding 16g of zinc powder into the three-neck flask in total, releasing heat in the adding process of the zinc powder, adding ice blocks into the water bath box at the moment, maintaining the temperature of the water bath box within the range of 25-40 ℃, enabling the water bath box to have a constant temperature function, maintaining the constant environmental temperature in the reaction process through the water bath box, adding water into the water tank when the water bath box is used, then switching on a power supply, shifting a temperature selection switch to a setting end, adjusting a temperature selection knob, simultaneously observing digital display readings, setting a required temperature value (accurate to 0.1 ℃), when the set temperature value exceeds the water temperature, the heating indicator lamp is turned on to indicate that the heater starts to work, the selection switch is turned to the measuring end at the moment, the actual water temperature is displayed through digital display, and when the water temperature reaches the required water temperature, the constant temperature indicator lamp is turned on and the heating indicator lamp is turned off;

s2, after the zinc powder is added, continuously keeping the temperature of the water bath box within the range of 25-40 ℃, and stirring for reacting for 1.5 hours; stirring the excessive zinc powder removed by filtering for 1-3 minutes by using 1-2% dilute hydrochloric acid, filtering, and washing a filter cake by using water, ethanol and diethyl ether in sequence to obtain dry and activated zinc powder, wherein the recovery of the zinc powder in the reaction process is beneficial to saving resources and reducing the production cost of furanone;

s3, after the reaction is finished, filtering under reduced pressure to remove excessive zinc powder and part of saturated and precipitated zinc acetate, evaporating the filtrate under reduced pressure to dryness of the aqueous solution on a rotary evaporator at a temperature lower than 55 ℃, leaching twice with 80mL of ethyl acetate, filtering to remove zinc acetate crystals, drying the filtrate, distilling at normal pressure to recover the ethyl acetate solvent, and obtaining 19g of light yellow oily viscous liquid; in the two-time leaching process of 80mL ethyl acetate, the dosage of the first ethyl acetate is 50mL, the dosage of the second ethyl acetate is 30mL, and the leaching temperature is controlled within the range of 35-40 ℃;

s4, adding a mixed solution of 20mL of n-butanol and 16mL of petroleum ether into the yellowish oily viscous liquid, crystallizing at a low temperature of-5-0 ℃, filtering and drying to obtain 9.4g of threo-type 3, 4-dihydroxy-2, 5-hexanedione, wherein the melting point of the threo-type 3, 4-dihydroxy-2, 5-hexanedione is 90 ℃, the melting point of the prepared erythro-type 3, 4-dihydroxy-2, 5-hexanedione is 60 ℃, and a vacuum drying oven is adopted for drying, wherein the use environment of the vacuum drying oven requires as follows: a. temperature: 5-40 ℃; b. relative humidity: RH is less than or equal to 85 percent; c. power supply voltage: 220V +/-10% and 50 Hz; d. the surrounding is not influenced by strong vibration and corrosive gas; the electric heating vacuum drying box can keep a certain vacuum degree in the working chamber and set, display and control the temperature by adopting an intelligent digital temperature regulator; the temperature regulator adopts computer technology to collect and process temperature signals in the working chamber, so that the temperature in the working chamber can be automatically kept constant, and the temperature control system belongs to P.I.D. intelligent temperature control, and has reliable performance and convenient use;

s5, decompressing the filtrate after the threo-type 3, 4-dihydroxy-2, 5-hexanedione is separated, removing the solvent to obtain yellow oily liquid, adding a mixed solution of chloroform and petroleum ether, adding the erythro-type 3, 4-dihydroxy-2, 5-hexanedione as a seed crystal, crystallizing at low temperature, and filtering to obtain the erythro-type 3, 4-dihydroxy-2, 5-hexanedione; the prepared conjugate comprises threo 3, 4-dihydroxy-2, 5-hexanedione and erythro 3, 4-dihydroxy-2, 5-hexanedione, wherein the threo 3, 4-dihydroxy-2, 5-hexanedione accounts for 83% of the total amount, and the erythro 3, 4-dihydroxy-2, 5-hexanedione accounts for 18% of the total amount;

step three, preparing furanone: adding 10ml of Na2HPO4 aqueous solution into the prepared conjugate, reacting for 24 hours at a certain temperature, adding acetic acid into the solution to adjust the pH value of the solution, standing and cooling the solution after reaction at normal temperature, separating out an oil phase and a water phase after standing for a period of time, concentrating the water phase to recover sodium dihydrogen phosphate, returning to the cyclization reaction, and discharging wastewater; concentrating an oil phase to recover butyl acetate and obtain a liquid-phase crude furanone product, performing freeze crystallization and centrifugal separation on the crude furanone product to obtain a crude furanone, dissolving the crude furanone into ethanol and ethyl acetate for extraction, wherein the volume ratio of the ethanol to the ethyl acetate is 1:1.1-8.2, filtering out impurities, performing freeze crystallization and centrifugal separation to obtain a finished furanone product, drying the wet finished furanone product to obtain a finished furanone product, and drying by using a vacuum drying oven, wherein the use environment requirement of the vacuum drying oven is as follows: a. temperature: 5-40 ℃; b. relative humidity: RH is less than or equal to 85 percent; c. power supply voltage: 220V +/-10% and 50 Hz; d. the surrounding is not affected by strong vibration and corrosive gas.

Although the invention has been described in detail above with reference to a general description and specific examples, it will be apparent to one skilled in the art that modifications or improvements may be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.