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CN-122010714-A - Method for efficiently synthesizing isopentenyl acid

CN122010714ACN 122010714 ACN122010714 ACN 122010714ACN-122010714-A

Abstract

The invention discloses a method for efficiently synthesizing isopentenyl acid. Under the condition of heating and stirring, acetone and methyl pyruvate are dripped into alkali liquor to obtain 4-hydroxy-4-methyl-2-ketovalerate sodium, sulfuric acid and hydrogen peroxide are sequentially added, and then sectional heating is carried out to obtain isopentenyl acid. The invention synthesizes the isopentenyl acid by using acetone and methyl pyruvate as raw materials through a two-step one-pot method, and realizes the efficient conversion of the raw materials of acetone and methyl pyruvate which are cheap and easy to obtain into the isopentenyl acid. The method has the advantages of high yield, high safety, clean reaction, less three wastes and the like. The reaction of the invention is carried out in water phase, avoiding the use of a large amount of organic solvents, and the sodium bicarbonate, sulfuric acid and hydrogen peroxide are all conventional chemicals, and the invention has simple post-treatment and less three wastes, and accords with the principle of green chemistry. The total yield (calculated by methyl pyruvate) of the isopentenyl acid can reach more than 87%, and the method has high industrial application value.

Inventors

  • FENG QIBIN
  • LU FUJUN
  • Han Xingyou
  • WANG ZHAOLI
  • ZHANG XIAOXIA
  • YUE TAO

Assignees

  • 青岛科技大学

Dates

Publication Date
20260512
Application Date
20260120

Claims (9)

  1. 1. A method for efficiently synthesizing isopentenyl acid, which is characterized by comprising the following steps: Under the condition of heating and stirring, acetone and methyl pyruvate are dripped into alkali liquor to obtain 4-hydroxy-4-methyl-2-ketovalerate sodium, sulfuric acid and hydrogen peroxide are sequentially added, and then sectional heating is carried out to obtain isopentenyl acid.
  2. 2. The method of claim 1, wherein the temperature of the heating and stirring is 40-60 ℃, and the reaction is continued for 1-2 hours after the addition of the acetone and the methyl pyruvate is completed.
  3. 3. The method of claim 1, wherein the molar ratio of acetone to methyl pyruvate is 1.05-1.6:1.
  4. 4. The method according to claim 1, wherein the alkali solution is sodium bicarbonate solution with a concentration of 1.5-2.0 mol/L and a molar ratio of sodium bicarbonate to methyl pyruvate of 1.2-1.6:1.
  5. 5. The method of claim 1, wherein the dripping time of the acetone and the methyl pyruvate is 2-4 hours.
  6. 6. The method according to claim 1, wherein the mass concentration of the sulfuric acid is 40%, and the molar ratio of the sulfuric acid to the sodium bicarbonate is 0.6-0.8:1.
  7. 7. The method of claim 1, wherein the mass concentration of the hydrogen peroxide is 25-30%, and the addition amount of the hydrogen peroxide is 0.95-1.2 eq of methyl pyruvate.
  8. 8. The method according to claim 1, wherein the step-wise heating is performed by heating to 40-50 ℃ first, heating to 2h, heating to 70-80 ℃ after no bubble emerges from the system, and heating for 1-3 hours.
  9. 9. Use of the method according to any one of claims 1 to 8 for increasing the yield of isopentanoic acid and for reducing work-up.

Description

Method for efficiently synthesizing isopentenyl acid Technical Field The invention relates to the technical field of organic synthesis, in particular to a method for efficiently synthesizing isopentenyl acid. Background Isopentenic acid, also known as 3, 3-dimethyl acrylic acid, is an important fine chemical raw material and is widely applied to various fields such as medicines, pesticides, spices and the like. In the aspect of medicine synthesis, the isopentenyl acid can be used as a key precursor to synthesize medicines such as antibiotics. In the field of food processing, the isopentenyl acid can be used as an additive to prepare food essence, so that the food flavor is improved. In the field of daily chemicals, isopentenyl acid can be used as an important component of perfume and cosmetic essence. It can also be used in the pesticide field to play a role in improving the pesticide effect. The prior synthesis method of the isopentenyl acid mainly comprises the following steps of taking mesityl oxide as a raw material, reacting with hypohalite to generate corresponding isopentenyl acid salt, and acidifying to obtain the isopentenyl acid. The method is a main industrial synthesis method of the isopentenyl acid, the mesityl oxide is condensed from acetone, a polymer is generated by the reaction, the yield is low, and the maximum yield is only 80%. And secondly, sodium hypochlorite is used as an oxidant to generate a large amount of salt-containing wastewater. The yield of isopentenyl acid was about 85% based on mesityl oxide. The yield of the method still has room for improvement, and the three wastes are polluted greatly; ; U.S. patent No. 2450117a reports that using ketene and acetone to produce [2+2] cycloaddition reaction under the catalysis of zinc thiocyanate, dimethyl substituted propiolactone is produced, and then the prenic acid is obtained by hydrolysis and elimination. The reaction yield is only 40-50% based on ketene, the reaction yield is low, and the production cost of the isopentenyl acid is high. And raw material ketene is generated by acetic acid pyrolysis or acetone pyrolysis, so that the source is limited, and a certain safety risk exists; ; CN1069629C discloses a process for directly dehydrating to obtain α, β -unsaturated acids using concentrated sulfuric acid or concentrated polyphosphoric acid as a dehydrating agent. However, the method still has the technical problems that 1) the applicable substrate range is limited, and the claims and the examples limit the substrate to an alpha-aryl-containing system, so that the substrate is difficult to extrapolate to a wider substrate. 2) The dehydration process requires an excessive amount of concentrated sulfuric acid or phosphoric acid, and the strong acid system causes severe heat release of the reaction system and may cause excessive oxidation of the substrate/product, thereby being disadvantageous in process safety and selectivity control. Therefore, development of a novel synthesis method of prenoic acid is needed to solve the problems of low yield, high cost, large environmental pollution and the like in the prior art. Therefore, the high-efficiency conversion of the isopentenyl acid is realized by using cheap and easily available raw materials, the yield is higher, the production cost is lower, and the environment-friendly and green chemical requirements are met. Disclosure of Invention In view of the above prior art, it is an object of the present invention to provide a method for efficiently synthesizing isopentenyl acid. The invention synthesizes the isopentenyl acid by using acetone and methyl pyruvate as raw materials through a two-step one-pot method, and realizes the efficient conversion of the raw materials of acetone and methyl pyruvate which are cheap and easy to obtain into the isopentenyl acid. The method has the advantages of high yield, high safety, clean reaction, less three wastes and the like. In order to achieve the above purpose, the invention adopts the following technical scheme: in a first aspect of the present invention, there is provided a method for efficiently synthesizing isopentenyl acid, the method comprising: Under the condition of heating and stirring, acetone and methyl pyruvate are dripped into alkali liquor to obtain 4-hydroxy-4-methyl-2-ketovalerate sodium, sulfuric acid and hydrogen peroxide are sequentially added, and then sectional heating is carried out to obtain isopentenyl acid. Preferably, the temperature of the heating and stirring is 40-60 ℃, and the reaction is continued for 1-2 hours after the dripping of the acetone and the methyl pyruvate is finished. Preferably, the molar ratio of the acetone to the methyl pyruvate is 1.05-1.6:1. Preferably, the alkali liquor is sodium bicarbonate solution with the concentration of 1.5-2.0 mol/L, and the molar ratio of sodium bicarbonate to methyl pyruvate is 1.2-1.6:1. Preferably, the dripping time of the acetone and the methyl pyruvate is 2-4 hours. Pr