Menthone preparing method

A technology of menthone and isopulegol, which is applied in the field of preparation of menthone, can solve the problems of short catalyst life and adverse environmental impact, and achieve the effects of simplified later stage purification treatment, good industrialization prospects, and remarkable operability

Active Publication Date: 2018-01-19
WANHUA CHEM GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The process has a limited improvement in the turnover number (TON), the catalyst life is still short, and it also requ

Method used

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] In an oxygen-free and water-free atmosphere, 6.46 mg of triruthenium dodecacarbonyl, 0.013 mg of cyclopentadiene, and 154.25 g of isopulegol were transferred to a 500-mL Schlenk flask equipped with a magnet, and stirred until the mixture was clear and transparent. The absolute pressure of the reaction was maintained at 0.1 Mpa by feeding high-purity nitrogen, and the mixture was heated to 100° C. and stirred for 100 hours. Conversion and menthone yield were determined by calibrated GC analysis. The results are summarized in Table 1.

Embodiment 2

[0042] In an oxygen-free and water-free atmosphere, 5.56 mg of ruthenium acetate, 0.22 mg of cyclooctadiene, and 169.68 g of isopulegol were added to a 500 ml Schlenk flask equipped with a magnet, and stirred until the mixture was clear and transparent. The absolute pressure of the reaction was maintained at 0.2 Mpa by feeding high-purity argon, and the mixture was heated to 140° C. and stirred for 80 hours. Conversion and menthol yield were determined by calibrated GC analysis. The results are summarized in Table 1.

Embodiment 3

[0044] In an oxygen-free and water-free atmosphere, 20.7 mg of ruthenium chloride, 13.8 mg of cyclopentene and 200.53 g of isopulegol were added to a 500 ml Schlenk flask equipped with a magnet, and stirred until the mixture was clear and transparent. The absolute pressure of the reaction was maintained at 1 Mpa by feeding high-purity nitrogen, and the mixture was heated to 160° C. and stirred for 10 hours. Conversion and menthol yield were determined by calibrated GC analysis. The results are summarized in Table 1.

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Abstract

The invention discloses a menthone preparing method. A transition metal complex is taken as a homogeneous catalyst, a small quantity of auxiliaries are added, so that menthone is prepared from isopulegol by hydrogen transfer, the reaction selectivity is 85%-99%, the conversion rate can reach 80%-99.9%, and the TON (turn-over number) of the homogeneous catalyst can reach 1,000-100,000.

Description

technical field [0001] The invention belongs to the field of preparation of menthone, in particular to a method for preparing menthone from isopulegol using a homogeneous catalyst. Background technique [0002] There are many ways to synthesize menthone, mainly based on the oxidation of menthol, using stoichiometric oxidation systems such as chromate, permanganate and hypochlorite. Although the process of this route is mature, the oxidant involved in the process It is toxic or dangerous, and requires a large amount of volatile organic solvents when used, so a large amount of waste liquid and by-product salt will be generated during the production process. [0003] Patent US3124614 reports that menthone can also be obtained by hydrogenating thymol under the action of Pd catalyst, but the raw material thymol is not easy to obtain. [0004] Patent CN106061933A reports a method for preparing menthone by contacting isopulegol in the gas phase with an activated oxidized copper ca...

Claims

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Application Information

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IPC IPC(8): C07C45/00C07C49/407
Inventor 王联防董菁张永振黎源王亚新于磊李晶杨洗李文滨
Owner WANHUA CHEM GRP CO LTD
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