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CN-122010707-A - Preparation method of 4-methyl-2-propylhexenal

CN122010707ACN 122010707 ACN122010707 ACN 122010707ACN-122010707-A

Abstract

The invention provides a preparation method of 4-methyl-2-propylhexenal, and relates to the technical field of organic synthesis. The preparation method comprises the steps of taking n-valeraldehyde and 2-methyl-butyraldehyde as reaction substrates, and reacting in a catalyst and a mixed solvent to obtain 4-methyl-2-propyl hexenal, wherein the catalyst is selected from alkali metal hydroxide and/or alkali metal alkoxide, and the mixed solvent comprises water and an alcohol organic solvent. The invention can catalyze the cross condensation reaction of n-valeraldehyde and 2-methyl-butyraldehyde to prepare 4-methyl-2-propyl hexenal with high selectivity. The method has the advantages of high conversion rate of reaction raw materials, mild reaction conditions, high product selectivity, simple separation and simple and convenient operation, and the 4-methyl-2-propyl hexenal prepared by the method is suitable for large-scale industrial production and is also suitable for full-industrialized extension of the high-carbon alcohol by hydroformylation of the mixed carbon tetraolefin.

Inventors

  • LI HONGCHEN
  • Zhao Zerun
  • WU TONG
  • CHEN HE
  • FU SONGBAO
  • WANG XINGYONG
  • Wang Weizhuang
  • LEI SHUAI
  • GUO LEI
  • WANG LU
  • CHAI WENZHENG

Assignees

  • 中国海洋石油集团有限公司
  • 中海石油炼化有限责任公司
  • 中海油化工与新材料科学研究院(北京)有限公司
  • 中海油石化工程有限公司

Dates

Publication Date
20260512
Application Date
20260203

Claims (10)

  1. 1. A method for preparing 4-methyl-2-propylhexenal, the method comprising: N-valeraldehyde and 2-methyl-butyraldehyde are used as reaction substrates, and the reaction is carried out in a catalyst and a mixed solvent to obtain 4-methyl-2-propyl hexenal; wherein the catalyst is selected from alkali metal hydroxide and/or alkali metal alkoxide, and the mixed solvent comprises water and alcohol organic solvent.
  2. 2. The method for producing 4-methyl-2-propylhexenal according to claim 1, wherein the molar ratio of n-valeraldehyde to 2-methyl-butyraldehyde is (1-5): 1, preferably (1-1.5): 1.
  3. 3. The method for producing 4-methyl-2-propylhexenal according to claim 1, wherein the hydroxide of an alkali metal is selected from any one or a combination of at least two of potassium hydroxide, sodium hydroxide, lithium hydroxide, preferably potassium hydroxide and/or sodium hydroxide, further preferably sodium hydroxide; Preferably, the alkali metal alkoxide is selected from sodium alkoxide and/or potassium alkoxide; preferably, the sodium alkoxide is selected from any one or a combination of at least two of sodium methoxide, sodium ethoxide and sodium tert-butoxide; Preferably, the potassium alkoxide is selected from any one or a combination of at least two of potassium methoxide, potassium ethoxide and potassium tert-butoxide.
  4. 4. The process for producing 4-methyl-2-propylhexenal according to claim 1 or 3, wherein the molar ratio of the catalyst to 2-methyl-butyraldehyde is (1 to 5): 1, preferably (1 to 2): 1.
  5. 5. The method for preparing 4-methyl-2-propylhexenal according to claim 1, wherein the alcoholic organic solvent is a C1 to C10 linear or branched alkyl alcohol, more preferably a C1 to C4 linear or branched alkyl alcohol; Preferably, the alcohol organic solvent is selected from any one or a combination of at least two of methanol, ethanol, isopropanol and tert-butanol, preferably methanol and/or ethanol, and more preferably ethanol.
  6. 6. The method for producing 4-methyl-2-propylhexenal according to claim 1 or 5, wherein the molar concentration of 2-methyl-butyraldehyde in the alcoholic organic solvent is 2 to 5 mol/L, preferably 3 to 4 mol/L.
  7. 7. The method for producing 4-methyl-2-propylhexenal according to claim 1, wherein the volume ratio of the water to the alcohol organic solvent is (1-5): 1, preferably (1.5-2): 1.
  8. 8. The method for producing 4-methyl-2-propylhexenal according to claim 1, wherein the reaction is carried out in an air atmosphere.
  9. 9. The method for preparing 4-methyl-2-propylhexenal according to claim 1, wherein the reaction temperature is 60-150 ℃, preferably 80-120 ℃.
  10. 10. The method for preparing 4-methyl-2-propylhexenal according to claim 1, wherein the reaction time is 1 to 12 hours, preferably 4 to 8 hours.

Description

Preparation method of 4-methyl-2-propylhexenal Technical Field The invention relates to the technical field of organic compound synthesis, in particular to a preparation method of 4-methyl-2-propylhexenal. Background 4-Methyl-2-propylhexenal is an important organic compound and is widely applied to the production of chemical industry, medicines, spices and pesticide intermediates. The unique chemical structure of the compounds makes the compounds important in perfume synthesis, and particularly can play a significant role in the preparation of perfumes and certain perfume products. 4-methyl-2-propylhexenal is widely used in the perfumery industry due to its excellent fragrance properties and strong chemical reactivity, in particular as a key component of fragrances and perfumes. In addition, it has potential pharmaceutical activity in the pharmaceutical field and can be used as an intermediate of certain drugs. With the rapid development of the fine chemical industry, the demand for high-quality and high-purity 4-methyl-2-propylhexenal is increasing. At present, the preparation method of 4-methyl-2-propylhexenal mainly comprises the following steps of 1) preparing the 4-methyl-2-propylhexenal through the oxidation reaction of unsaturated alcohol, but the method has the problems of harsh reaction conditions and lower yield. 2) The preparation is carried out by an addition reaction or a selective catalytic reaction of olefin, but the problems of poor stereoselectivity, more byproducts, complex post-treatment and the like are often accompanied. 3) The reaction is realized by multi-step reactions such as addition and condensation from simple aldehyde compounds, but the selectivity of reaction products is poor, and the mixture is difficult to separate. The prior art route has a plurality of challenges in chemoselectivity, side reaction control, stability under industrialized conditions and the like. Therefore, there is a need to develop an efficient industrial preparation method, especially for directly preparing 4-methyl-2-propylhexenal through condensation reaction with high selectivity based on the existing industrial raw materials of n-valeraldehyde and 2-methyl-butyraldehyde. In industrial production, the high added value utilization of the mixed carbon tetraolefins can prepare a mixture of n-valeraldehyde and 2-methyl-butyraldehyde by hydroformylation of butene, and the process has mature reaction path, abundant raw material sources and low price. In particular, n-valeraldehyde and 2-methyl-butyraldehyde have higher reactivity, and are important intermediates in organic synthesis. The two mixed raw materials are directly subjected to condensation reaction through a proper catalytic system, so that the 4-methyl-2-propyl hexenal is hopeful to be prepared with high selectivity. In 2001, klaus-Diether et al prepared 4-methyl-2-propylhexenal from n-valeraldehyde and 2-methyl-butyraldehyde in aqueous sodium hydroxide, but with a selectivity of only 24%, resulting in significant raw material waste and increased separation energy costs. In 2010 Alfred et al used n-valeraldehyde and 2-methyl-butyraldehyde as raw materials and sodium hydroxide as a catalyst, only a mixed product of 4-methyl-2-propylhexenal and 2-propyl-2 heptenal could be obtained at a high temperature of 130 ℃. In 2021, chai et al used n-valeraldehyde as the starting material to prepare a 2-propyl-2-heptenal product with high selectivity by self-condensation reaction, and the problem of poor selectivity of the condensation reaction could be avoided by using a single starting material. By analyzing the structure of the raw materials and the self steric hindrance characteristics, the n-valeraldehyde and the 2-methyl-butyraldehyde both contain alpha-H, can be used as an electrophile and a nucleophilic reagent, and have cross condensation reaction and self condensation reaction in a reaction system catalyzed by alkali, and theoretically have at least three products, thus leading to confusion of the reaction system. Although a method for synthesizing 4-methyl-2-propylhexenal exists, the problems of imperfect catalytic system, poor chemical selectivity, harsh reaction conditions, difficult post-treatment separation, waste of raw materials and the like still exist, and the industrial application is limited, so that the design of a new catalytic system for synthesizing 4-methyl-2-propylhexenal is very significant. In view of this, the present invention has been made. Disclosure of Invention The invention aims to provide a preparation method of 4-methyl-2-propylhexenal. The preparation method solves the technical problems of poor chemical selectivity, more side reactions, low raw material conversion rate, harsh reaction conditions and complex post-treatment in the existing preparation method of the 4-methyl-2-propylhexenal. In order to achieve the above object of the present invention, the following technical solutions are specifically adopted: in a first a