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CN-121990874-A - Method for preparing trans-4-methylcyclohexanol with high selectivity

CN121990874ACN 121990874 ACN121990874 ACN 121990874ACN-121990874-A

Abstract

The invention belongs to the field of organic synthesis, and discloses a method for preparing trans-4-methylcyclohexanol with high selectivity. The method comprises the steps of stirring nickel salt and ligand in an organic solvent I under the condition of inert gas to react to obtain a nickel catalyst, wherein the ligand is at least one of L1, L2 and L3: and (2) adding the nickel catalyst prepared in the step (1) and 4-methylphenol into a solvent II, and obtaining the trans-4-methylcyclohexanol through hydrogenation reaction. The method has mild reaction conditions and high product yield (91%), and 4-methylcyclohexanol with high trans-form ratio is obtained with high selectivity. The nickel catalyst has higher activity and lower cost, so the method is expected to be widely applied to the synthesis of trans-4-methylcyclohexanol.

Inventors

  • ZHANG PANKE
  • Xiao Yangdi
  • LIU XUELING
  • ZHONG MAOLIN

Assignees

  • 郑州大学

Dates

Publication Date
20260508
Application Date
20260130

Claims (10)

  1. 1. A method for preparing trans-4-methylcyclohexanol with high selectivity, which is characterized by comprising the following steps: (1) Stirring and reacting nickel salt and a ligand in an organic solvent I under the condition of inert gas to obtain a nickel catalyst, wherein the ligand is at least one of L1, L2 and L3: ; (2) Adding the nickel catalyst prepared in the step (1) and 4-methylphenol into a solvent II, and obtaining trans-4-methylcyclohexanol through hydrogenation reaction.
  2. 2. The method for preparing trans-4-methylcyclohexanol with high selectivity according to claim 1, wherein the molar ratio of nickel salt and ligand in the step (1) is 1:1-1.6.
  3. 3. The method for preparing trans-4-methylcyclohexanol with high selectivity according to claim 2, wherein the temperature of the stirring reaction in the step (1) is 60-120 ℃ and the time is 5-12 h.
  4. 4. The method for preparing trans-4-methylcyclohexanol with high selectivity according to claim 1, wherein the nickel salt in the step (1) is at least one of Ni(acac) 2 、NiCl 2 、NiBr 2 、NiI 2 、Ni(NTf 2 ) 2 、Ni(BF 4 ) 2 、Ni(OAc) 2 •4H 2 O、Ni(NO 3 ) 2 、NiSO 4 、Ni(OTs) 2 and Ni (ClO 4 ) 2 ).
  5. 5. The method for preparing trans-4-methylcyclohexanol with high selectivity according to claim 4, wherein the organic solvent I in the step (1) is any one of tetrahydrofuran, benzene, toluene, paraxylene, 1, 4-dioxane, dimethyl sulfoxide, 1, 2-dichloroethane, diethyl ether, cyclohexane, chloroform, dichloromethane and petroleum ether.
  6. 6. The method for preparing trans-4-methylcyclohexanol with high selectivity according to claim 5, wherein the amount of nickel catalyst added in the step (2) is 5-60% of the mass of 4-methylphenol.
  7. 7. The method for preparing trans-4-methylcyclohexanol with high selectivity according to claim 6, wherein the solvent II in the step (2) is any one of tetrahydrofuran, 1, 4-dioxane, dichloromethane, chloroform and diethyl ether.
  8. 8. The method for producing trans-4-methylcyclohexanol with high selectivity as claimed in claim 7, wherein the hydrogenation reaction in the step (2) is carried out at a temperature of 100-130 ℃ for a time of 5-12 h.
  9. 9. The method for producing trans-4-methylcyclohexanol with high selectivity as claimed in claim 8, wherein the pressure of hydrogen in the step (2) is 3-4 MPa.
  10. 10. Trans-4-methylcyclohexanol produced using the method of highly selective production of trans-4-methylcyclohexanol as claimed in any one of claims 1-9.

Description

Method for preparing trans-4-methylcyclohexanol with high selectivity Technical Field The invention belongs to the field of organic synthesis, and particularly relates to a preparation method of trans-4-methylcyclohexanol. Background 4-Methylcyclohexanol is a high boiling point solvent and perfume raw material with excellent properties, good solubility, unique fragrance quality and good safety. Compared with partial traditional chlorinated hydrocarbon or strong polar solvent, the compound has lower toxicity and irritation, safer use and storage, good dissolving capacity for resin, grease and wax substances, moderate volatilization rate, contribution to leveling of the coating, reduction of volatilization loss in the use process, and environmental protection and economy. The fragrant smell characteristic shows mild and durable costustoot/camphor-like smell, is suitable for perfumed soap, detergent and household fragrance products, can be used as a fragrance fixing agent and a blended perfume, and can effectively improve the texture and fragrance retention of the whole fragrance. The trans-4-methylcyclohexanol is a compound with a single three-dimensional structure, has uniform chemical properties, can be used as a chiral structural unit to be applied to the fields of medicines, materials, pesticides and the like, and particularly has more unique smell as a spice than 4-methylcyclohexanol, so that the development of the synthesis research of the trans-4-methylcyclohexanol has very important significance. The 4-methylcyclohexanol is generally synthesized by hydrogenation using 4-methylphenol as a raw material. The hydride reduction or catalytic hydrogenation of 4-methylphenol typically produces a mixture of cis and trans 4-methylcyclohexanol, and subsequent separation of the isomers by recrystallization, column chromatography, etc. is also required to obtain cis 4-methylcyclohexanol or trans 4-methylcyclohexanol. The method has the main defects that the reaction condition is severe, the method needs to be carried out at higher temperature and pressure, the equipment requirement is high, the energy consumption is high, the used catalyst is mostly noble metal or transition metal, the cost is high, the catalyst is easily influenced by impurities to be deactivated, the recycling is difficult, and the biggest challenge is that the process lacks stereoselectivity, and the isomer mixture of cis-form and trans-4-methylcyclohexanol can be synchronously generated. Due to the close physical and chemical properties, the subsequent separation and purification steps are complex, the yield is limited, and the cost is obviously improved, so that the high-purity product with a single configuration is difficult to obtain efficiently, and the deep application of the product in fine chemicals (such as high-end perfume) with specific three-dimensional structures is limited to a certain extent. Therefore, the development of a method for synthesizing trans-4-methylcyclohexanol by one-step hydrogenation of 4-methylphenol, which has the advantages of simple process, low cost and high selectivity of trans-products, has important significance. Disclosure of Invention Aiming at the technical problems, the invention provides a method for preparing trans-4-methylcyclohexanol with high selectivity. In order to achieve the above object, the technical scheme of the present invention is as follows: A method for preparing trans-4-methylcyclohexanol with high selectivity comprises the following steps: (1) Stirring and reacting nickel salt and a ligand in an organic solvent I under the condition of inert gas to obtain a nickel catalyst, wherein the ligand is at least one of L1, L2 and L3: ; (2) Adding the nickel catalyst prepared in the step (1) and 4-methylphenol into a solvent II, introducing hydrogen, and carrying out hydrogenation reaction to obtain trans-4-methylcyclohexanol. The specific reaction formula is as follows: 。 The molar ratio of the nickel salt to the ligand in the step (1) is 1:1-1.6. The temperature of the stirring reaction is 60-120 ℃ and the time is 5-12 h. Further, the nickel salt in the above step (1) is at least one of Ni(acac)2、NiCl2、NiBr2、NiI2、Ni(NTf2)2、Ni(BF4)2、Ni(OAc)2•4H2O、Ni(NO3)2、NiSO4、Ni(OTs)2 and Ni (ClO 4)2. The organic solvent I is any one of tetrahydrofuran, benzene, toluene, paraxylene, 1, 4-dioxane, dimethyl sulfoxide, 1, 2-dichloroethane, diethyl ether, cyclohexane, chloroform, methylene chloride and petroleum ether. The addition amount of the nickel catalyst in the step (2) is 5-60% of the mass of the 4-methylphenol. The solvent II is any one of tetrahydrofuran, 1, 4-dioxane, dichloromethane, chloroform and diethyl ether. Further, the pressure of the hydrogen gas in the step (2) is 3-4 MPa. The temperature of hydrogenation reaction is 100-130 ℃ and the time is 5-12 h. Trans-4-methylcyclohexanol prepared by the above-described method for preparing trans-4-methylcyclohexanol with high selectivity. In the hydr