Method for preparing cis-pinane by asymmetric catalytic hydrogenation of alpha-pinene

Abstract

The invention discloses a method for preparing cis-pinane by asymmetric catalytic hydrogenation of alpha-pinene, and belongs to the chemical engineering field. The method comprises the process steps: in a nitrogen atmosphere, heating RhCl3.3H2O to dissolve in an ethanol solution, and forming a solution A; dissolving newly recrystallized PPh3 in a deoxygenated ethanol, and forming a solution B; adding the solution B into the solution A, refluxing for a certain period of time, filtering under reduced pressure while being hot, washing with deoxygenated ether, carrying out vacuum drying to obtain a rhodium phosphine complex RhCl(PPh3)3; and adding the prepared rhodium phosphine complex RhCl(PPh3)3, an ionic liquid and alpha-pinene into a high-pressure reaction kettle according to a certain proportion, putting a cover and sealing, respectively replacing with nitrogen gas and hydrogen gas, carrying out pressure maintaining and leakage detection, and carrying out a reaction under certain conditions to prepare cis-pinane. The method has the advantages of mild reaction conditions, high conversion rate of alpha-pinene and high enantioselectivity of cis-pinane; the ionic liquid catalyst system is easily separated from the product and can be recycled; and the process flow is simple, and the energy consumption is low.

Description

technical field [0001] The invention relates to a method for preparing cis-pinane by asymmetric catalytic hydrogenation of α-pinene, which belongs to the field of chemical industry. Background technique [0002] α-pinene is the main component of turpentine, α-pinene can be produced by catalytic hydrogenation of pinane, pinane is an important raw material for the perfume and pharmaceutical industry, and is used to prepare linalool, citronellol, rose ether and dihydrogen An important intermediate of fragrances such as myrcenol. There are cis- and trans-isomers of pinane, because the reactivity of cis-pinane is much higher than that of trans-pinane, so the pinane used in the perfume industry requires cis-pinane as the main one. [0003] In the currently used method for preparing cis-pinane by hydrogenation of α-pinene, the catalyst is mostly a nickel catalyst. Although its production cost is low, the reaction temperature and pressure are high, and the requirements ...

AI Technical Summary

Problems solved by technology

[0003] In the currently used method for preparing cis-pinane by hydrogenating α-pinene, the catalyst is mostly a nickel catalyst. Although its production cost is relatively low, the reaction temperature and pressure are high, and the requirements for reaction equipment are high, and the operating conditions are harsh. The safety hazard is large, and the content of cis-pinane in the product is low, and the enantioselectivity is poor

However, noble metal catalysts such as palladium, platinum, and rhodium have high catalytic activity and relatively mild reaction conditions. In particular, noble metal homogeneous catalysts have superior performance in selective hydrogenation, but product separation and catalyst recovery are difficult.