Method of preparing isopulegol by cyclization reaction of citronellal

A technology of isopulegol and cyclization reaction, which is applied in the fields of chemical instruments and methods, reduction preparation of oxygen-containing functional groups, organic chemistry, etc., can solve the problems of unsuitable large-scale industrial production, frequent catalyst recycling operations, and slow reaction rate etc. to achieve the effects of fast reaction and mass transfer rate, easy serialization and automation, and simple method

Inactive Publication Date: 2017-07-14
SHANXI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] However, most of the catalytic reactions for the preparation of isopulegol from citronellal cyclization reported at present are completed in batch reactors, and batch reactions are only suitable for small batches and reactions with slow reaction rates. At the same time, the recycling operations of catalysts are frequent, High production cost, not suitable for large-scale industrial production

Method used

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  • Method of preparing isopulegol by cyclization reaction of citronellal
  • Method of preparing isopulegol by cyclization reaction of citronellal

Examples

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Effect test

Embodiment 1

[0032] 1) Weigh 1g of SiO with a diameter of 60-80nm 2 The particles were dispersed in 8 ml of toluene, and 0.1 g of propyltrimethoxysilane was added. Under the protection of nitrogen, it was stirred and refluxed at 110°C for 4 hours. After cooling, after high-speed centrifugation, toluene washing, and vacuum drying, the interface active nano-SiO can be obtained. 2 .

[0033] 2) 0.15g interface active nano-SiO 2 Disperse in 60ml toluene by ultrasonic wave, add 3ml 0.01mol / L phosphotungstic acid solution, stir to form Pickering emulsion. After milking, 0.6g of HSi(OCH 3 ) 3 Add it into the emulsion system, mix evenly, hydrolyze at 30°C for 24 hours, then let it stand, remove the upper oil phase, wash it with toluene three times, and you can get the microcapsules encapsulating the phosphotungstic acid catalyst.

[0034] 3) Slowly transfer the microcapsules of the encapsulated phosphotungstic acid catalyst prepared above to an inner diameter of 0.8cm continuous flow reactio...

Embodiment 2

[0036] 1) Weigh 1g of SiO with a diameter of 60-80nm 2 The particles were dispersed in 8 ml of toluene, and 0.6 g of propyltrimethoxysilane was added. Under the protection of nitrogen, it was stirred and refluxed at 110°C for 4 hours. After cooling, after high-speed centrifugation, toluene washing, and vacuum drying, the interface active nano-SiO can be obtained. 2 .

[0037] 2) 0.3g interface active nano-SiO 2 Disperse in 110ml of n-octane by ultrasonic wave, add 7.5ml of phosphotungstic acid solution with a concentration of 0.05mol / L, and stir to form a Pickering emulsion. After milking, 1.5g of Si(OC 2 h 5 ) 4 Add it into the emulsion system, mix well, hydrolyze at 50°C for 24 hours, then let it stand still, remove the upper oil phase, wash it with n-octane three times, and you can get the microcapsules encapsulating the phosphotungstic acid catalyst.

[0038] 3) Slowly transfer the microcapsules of the encapsulated phosphotungstic acid catalyst prepared above to a c...

Embodiment 3

[0040] 1) Weigh 1g of SiO with a diameter of 60-80nm 2 The particles were dispersed in 8 ml of toluene, and 0.3 g of propyltrimethoxysilane was added. Under nitrogen protection, stir and reflux at 110°C for 5 hours. After cooling, after high-speed centrifugation, toluene washing, and vacuum drying, the interface active nano-SiO can be obtained. 2 .

[0041] 2) 0.5g interface active nano-SiO 2 Disperse in 150ml of n-hexane by ultrasonic waves, then add 15ml of phosphotungstic acid solution with a concentration of 0.08mol / L, and stir to form a Pickering emulsion. After milking, 1.25g of Si(OCH 3 ) 4 Add it into the emulsion system, mix evenly, hydrolyze at 30°C for 24 hours, let it stand still, remove the upper oil phase, wash it with n-hexane three times, and you can get the microcapsules encapsulating the phosphotungstic acid catalyst.

[0042] 3) Slowly transfer the microcapsules of the encapsulated phosphotungstic acid catalyst prepared above to an inner diameter of 2c...

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Abstract

The invention provides a method of preparing isopulegol by a cyclization reaction of citronellal. The method comprises the following steps: with nano silicon oxide with interfacial activity as an emulsion stabilizer, phosphotungstic acid as an aqueous phase and an organic solvent as an oil phase, stirring to form a Pickering emulsion of water in oil; then with the Pickering emulsion as a template, performing surface chemical crosslinking to prepare microcapsules packaging a phosphotungstic acid catalyst inside; and filling a continuous flowing reaction column with the microcapsules as a fixed phase, inputting dextrocitronellal as a moving phase from the upper end of a reactor, wherein a product flows out from the bottom of the reactor. The reaction system can provide a relatively large reaction interface, and can repeatedly use the catalyst while keeping excellent catalytic performance of phosphotungstic acid. After continuous reaction for 1000 hours, the conversation ratio still can be kept at 90% and above, and the selectivity on isopulegol can reach 60%-75%.

Description

technical field [0001] The invention relates to the technical field of catalytic reactions, in particular to a method for preparing isopulegol by cyclization reaction of citronellal. Background technique [0002] As an important spice, menthol is widely used in cosmetics, beverages, food and medicine. In the chemical synthesis route, menthol is usually obtained by hydrogenation of isopulegol. And isopulegol, as an important intermediate of menthol, is mainly produced by (+)-citronellal cyclization reaction at present. [0003] Published catalysts for the cyclization of citronellal to isopulegol include Lewis acids such as ZnCl 2 , ZnBr 2 , AlCl 3 , BF 3 and SbCl 3 etc.; heterogeneous catalysts such as molecular sieves, activated carbon, silica gel and new metal-organic frameworks (MOFs), etc., as well as phosphotungstic acid, sulfuric acid, boric acid, phosphoric acid, etc. Silva et al. adopted H 3 PW 12 o 40 / SiO 2 As a catalyst, it is used for the cyclization re...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C29/14C07C35/17B01J27/188B01J35/02
CPCB01J27/188B01J35/02C07C29/14C07C35/17
Inventor 杨恒权郝雅娟陈欢张明
Owner SHANXI UNIV
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