阅读说明：本技术 二氢茉莉酮酸甲酯合成中无有机溶剂异构化制备戊基环戊烯酮的方法 (Method for preparing amyl cyclopentenone without isomerization of organic solvent in synthesis of methyl dihydrojasmonate ) 是由 李向前 孙学剑 张坚 赵成进 李瀛 张鹏飞 于 2019-09-25 设计创作，主要内容包括：本发明公开了二氢茉莉酮酸甲酯合成中无有机溶剂异构化制备戊基环戊烯酮的方法,包括以下步骤：将对甲苯磺酸与醋酐在反应器中搅拌混合,搅拌下加热至120±2℃,滴加亚戊基环戊酮,滴加完成后,118-122℃保温搅拌2-4h,反应结束后,降温,用碳酸钠溶液调节反应液的pH为7.5-9,静置分层,油相即为戊基环戊烯酮粗品。异构化过程中,不使用有机溶剂,实现清洁绿色生产。(The invention discloses a method for preparing amyl cyclopentenone by organic solvent-free isomerization in methyl dihydrojasmonate synthesis, which comprises the following steps: stirring and mixing p-toluenesulfonic acid and acetic anhydride in a reactor, heating to 120 +/-2 ℃ under stirring, dropwise adding pentylene cyclopentanone, after dropwise adding, keeping the temperature at 118 ℃ and 122 ℃ and stirring for 2-4h, after the reaction is finished, cooling, adjusting the pH of the reaction solution to 7.5-9 by using a sodium carbonate solution, standing and layering, wherein the oil phase is a crude product of pentylcyclopentenone. In the isomerization process, no organic solvent is used, and clean and green production is realized.)

1. The method for preparing the pentylcyclopentenone without isomerization of an organic solvent in the synthesis of methyl dihydrojasmonate is characterized by comprising the following steps of:

stirring and mixing p-toluenesulfonic acid and acetic anhydride in a reactor, heating to 120 +/-2 ℃ under stirring, dropwise adding pentylene cyclopentanone, after dropwise adding, keeping the temperature at 118 ℃ and 122 ℃ and stirring for 2-4h, after the reaction is finished, cooling, adjusting the pH of the reaction solution to 7.5-9 by using a sodium carbonate solution, standing and layering, wherein the oil phase is a crude product of the pentylcyclopentenone, and the crude product is rectified to obtain the crude product of the pentylcyclopentenone.

2. The method for preparing the pentylcyclopentenone without isomerization of an organic solvent in the synthesis of methyl dihydrojasmonate according to claim 1, wherein: when the pentamethylene cyclopentanone is added, the temperature of the reaction solution is controlled at 118-122 ℃.

3. The method for preparing the pentylcyclopentenone without isomerization of an organic solvent in the synthesis of methyl dihydrojasmonate according to claim 1, wherein the dropping speed of the pentylenecyclopentanone is 16 ~ 24 kg/min.

4. The method for preparing the pentylcyclopentenone without isomerization of an organic solvent in the synthesis of methyl dihydrojasmonate according to claim 1, wherein: the concentration of the sodium carbonate solution is 10% -13%.

5. The method for preparing the pentylcyclopentenone without isomerization of organic solvent in the synthesis of methyl dihydrojasmonate according to claim 1, wherein the mass ratio of pentylidene cyclopentanone, toluene sulfonic acid, and acetic anhydride is 200:0.8 ~ 1.2.2: 20 ~ 30.

Technical Field

The invention belongs to the technical field of organic synthesis, relates to synthesis of perfume compounds, and particularly relates to a method for preparing pentalenone by isomerization without organic solvent in synthesis of methyl dihydrojasmonate.

Background

Jasmine flower fragrance compounds have been studied for several tens of years, and with the increasing demand for such compounds, the industrialization rate is far from meeting the demand. Methyl Dihydrojasmonate (MDJ) belongs to jasmone compounds, is one of important artificially synthesized jasmine perfumes, has no related report that the methyl dihydrojasmonate exists in natural perfume, and is an important perfume variety in the modern perfume industry due to relatively low price and wide application range. The liquid fragrance agent is colorless or light yellow transparent liquid in appearance, has stable chemical property, and has the advantages of slow volatilization, long fragrance retention time, no discoloration when used for blending fragrance, and the like. Not only can be applied to cosmetics, but also can be used as a synergist in food essence and can be used as a coordinator of other flower fragrance essences.

Since the forties of the last century, people began to explore the artificial synthesis of methyl dihydrojasmonate, and through years of research, dozens of different synthetic routes have been developed, thus achieving considerable success. At present, the industrial production route of methyl dihydrojasmonate is mainly to obtain a key 2-pentyl-2-cyclopentenone intermediate from cyclopentanone and n-valeraldehyde through aldol condensation and strong acid isomerization, perform addition on the 2-pentyl-2-cyclopentenone intermediate by dimethyl malonate, and then perform decarboxylation to obtain a methyl dihydrojasmonate product.

The strong acid isomerization reaction adopts the process that xylene is used as a solvent, p-toluenesulfonic acid is used as an acid catalyst, acetic anhydride is used as an auxiliary catalyst, pentylene cyclopentanone is isomerized into pentylcyclopentenone, and a large amount of xylene is used in industrial production, so that the treatment cost of dangerous waste of enterprises is increased, great pressure is brought to the environment, and the sustainable development of economy and environment is not facilitated.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a method for preparing the pentalenone by isomerization without an organic solvent in the synthesis of methyl dihydrojasmonate, and the clean and green production is realized without using the organic solvent in the isomerization process.

The invention is realized by the following technical scheme:

the method for preparing the pentylcyclopentenone without isomerization of an organic solvent in the synthesis of the methyl dihydrojasmonate comprises the following steps of:

stirring and mixing p-toluenesulfonic acid and acetic anhydride in a reactor, heating to 120 +/-2 ℃ under stirring, dropwise adding pentylene cyclopentanone, after dropwise adding, keeping the temperature at 118 ℃ and 122 ℃ and stirring for 2-4h, after the reaction is finished, cooling, adjusting the pH of the reaction solution to 7.5-9 by using a sodium carbonate solution, standing and layering, wherein the oil phase is a crude product of the pentylcyclopentenone, and the crude product is rectified to obtain the crude product of the pentylcyclopentenone.

The invention further improves the scheme as follows:

when the pentamethylene cyclopentanone is added, the temperature of the reaction solution is controlled at 118-122 ℃.

The dropping speed of the addition of the pentamethylene cyclopentanone is 16 ~ 24 kg/min.

The concentration of the sodium carbonate solution is 10% -13%.

The mass ratio of the pentylidene cyclopentanone to the toluenesulfonic acid to the acetic anhydride is 200:0.8 ~ 1.2.2: 20 ~ 30.

The invention has the beneficial effects that:

according to the preparation method, an organic solvent is not used, after the reaction is finished, the obtained crude product of the pentylcyclopentenone is directly obtained, distillation is not needed, and the crude product of the pentylcyclopentenone is directly rectified to obtain the finished product of the pentylcyclopentenone, so that the cost and the energy are saved, and the method is clean and pollution-free.

The acetic anhydride used in the invention is used as an auxiliary catalyst to promote the isomerization of the pentamethylene cyclopentanone to generate the pentamethylene cyclopentenone, is also used as a reaction solvent, and is also used as a water absorbent to reduce the moisture in the system, thereby being more beneficial to the isomerization.

Detailed Description