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Method for preparing citral through rearrangement reaction of dehydrolinalool

A technology of dehydrolinalool and rearrangement reaction, applied in the field of preparation of citral, can solve the problems of difficult separation of catalyst and product, low activity of molybdenum-based catalyst, expensive catalyst, etc., and achieves good economic benefits and application prospects , convenient source of raw materials, high reactivity and selectivity

Inactive Publication Date: 2015-01-21
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The activity of molybdenum-based catalysts is not high, the reaction time is long, the price of the catalyst is relatively expensive, and it is difficult to separate the catalyst from the product

Method used

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  • Method for preparing citral through rearrangement reaction of dehydrolinalool
  • Method for preparing citral through rearrangement reaction of dehydrolinalool
  • Method for preparing citral through rearrangement reaction of dehydrolinalool

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Preparation of catalyst 1,2-bis(diphenylphosphine)ethane-bis(2-methylpropenyl)ruthenium

[0023] Add 5 g of (1,5-cyclooctadiene) ruthenium dichloride into the tetrahydrofuran solution of 2-methallylmagnesium chloride, stir and heat to reflux for 2 hours under the protection of nitrogen, and filter the solution through diatomaceous earth after the reaction. Add about 100mL of water to the filtrate, extract twice with 100mL of anhydrous ether after hydrolysis, take the organic phase and add anhydrous calcium chloride to remove water, and filter through about 2g of neutral alumina. The filtrate was evaporated to dryness at 70°C, and after cooling, methanol was added to precipitate a gray solid, which was recrystallized from petroleum ether-methanol to obtain bis(2-methallyl)-1,5-cyclooctadiene ruthenium.

[0024] In a 250mL three-necked flask, add 150mL of n-hexane, 5g of bis(2-methallyl)-1,5-cyclooctadiene ruthenium and 6g of 1,2-bis(diphenylphosphine)ethane, Under the p...

Embodiment 2

[0026] Preparation of citral

[0027] Put 30.5g (0.2mol) of dehydrolinalool, 175mL (151g) of solvent toluene, and 24.4g (0.2mol) of benzoic acid into a 250mL three-necked flask, start stirring under the protection of nitrogen, and then add catalyst 1,2 -Bis(diphenylphosphine)ethane-bis(2-methylpropenyl)ruthenium 1.2g (0.2mmol), heat up to 70°C in the first stage, keep the constant temperature for 1h, then heat up to 120°C in the second stage for reaction 6h, after the reaction was finished, samples were taken, and the concentration of each component in the reaction solution was analyzed by gas chromatography, and the reaction conversion rate and yield were calculated. The reaction results are listed in Table 2.

Embodiment 3-11

[0029] The specific raw material proportions and reaction conditions of each embodiment are shown in Table 1, and the reaction results are listed in Table 2.

[0030] Table 1

[0031]

[0032] Table 2

[0033]

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Abstract

The invention relates to a method for preparing citral through a rearrangement reaction of dehydrolinalool. The method includes a step of performing catalytic rearrangement reaction with the dehydrolinalool as a raw material and with addition of a catalyst 1,2-bis(diphenylphosphine)ethane-bis(2-methylpropenyl)ruthenium in the presences of a solvent and a co-catalyst to obtain the citral. The catalyst is high in reaction activity and selectivity. Through the catalytic rearrangement reaction, ideal conversion ratio and yield of a target product can be achieved. The catalyst is simple in preparation process, is wide in raw material sources and has excellent economic benefit and application prospect in preparation of the citral.

Description

technical field [0001] The invention belongs to the field of preparation of citral, in particular to a method for preparing citral through dehydrolinalool rearrangement reaction. Background technique [0002] Citral is a colorless or slightly yellowish liquid with a strong lemon flavor, which can be used to make citrus-flavored food flavors, directly used in beverages and food processing. As one of the most important open-chain monoterpenes, citral is a fine chemical intermediate with broad application prospects. It can be used to synthesize isopulegol, hydroxycitronellal and ionone, and can also be converted into vitamin E, Important starting material for Vitamin A, Isophytol or β-Genone. [0003] Natural citral exists in plant essential oils such as litsea cubeba oil, maple grass oil, lemongrass oil, eucalyptus oil, grass oil, lemon basil oil, etc. Domestic citral products are mainly extracted from plant essential oils, which are limited by raw material resources. Suitab...

Claims

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Application Information

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IPC IPC(8): C07C47/21C07C45/67
CPCC07C45/512B01J31/2409B01J2231/645B01J2231/52B01J2531/0241B01J2531/821B01J35/19C07C47/21
Inventor 朱志庆许惠明孙春水秦技强吴忠平王继媛
Owner CHINA PETROLEUM & CHEM CORP
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