Method for preparing alpha-hexylcinnamyl aldehyde

Abstract

The invention provides a method for preparing alpha-hexylcinnamyl aldehyde. The method comprises the following steps: carrying out cross condensation on phenylpropanal and hexanal to obtain a 2-benzyl-2-octenal intermediate, and carrying out hydroisomerization on the intermediate to obtain alpha-hexylcinnamaldehyde. According to the synthesis route, phenylpropanal and hexanal which are simple, easy to obtain and low in cost are used as starting raw materials, and the use of an expensive n-octanal raw material in a traditional route is avoided; and secondly, the alpha-methylcinnamyl aldehyde is obtained at high yield through condensation and isomerization reactions, the route yield is high, and the method has a good economic value.

Description

technical field [0001] The invention belongs to the fields of fine chemicals and flavors and fragrances, and in particular relates to a method for preparing alpha-hexyl cinnamaldehyde. Background technique [0002] α-Hexylcinnamaldehyde, also known as 2-hexylcinnamaldehyde, is a yellow oily liquid at room temperature, with a fresh and sweet jasmine fragrance, with a boiling point of 305°C and a flash point of >93°C. α-Hexylcinnamaldehyde is one of the most floral varieties in synthetic fragrances, and it has a pleasant oily green smell. It can be used in combination with many floral fragrances to make its fragrance better. In addition to being widely used in cosmetics, soaps, perfumes and other fields as daily flavors, α-hexyl cinnamaldehyde can also be used in food in a small amount as honey and fruity flavors. [0003] At present, the main synthesis method of α-hexylcinnamaldehyde is the condensation reaction of benzaldehyde and n-octylaldehyde. Raw material benzaldeh...

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Problems solved by technology

Raw material benzaldehyde is mainly by-product of toluene oxidation, the main product of toluene oxidation is benzoic acid, a small amount of by-product benzaldehyde, the price is more expensive; another method is toluene dichlorination, hydrolysis to obtain benzaldehyde, but the benzene obtained by this method Formaldehyde remains a halogen, so it has a bad smell and is difficult to use in fragrance products

Another raw material, n-octanal, is basically obtained by oxidation or dehydrogenation of n-octanol at present; the price of n-octanol is more expensive, mainly because its source is limited. At present, it is mainly obtained from the separation of natural fatty alcohols, and n-octanol in natural fatty alcohols The content is less than 10%, the separation and purification process is cumbersome, and the yield of n-octanol obtained is not high

[0007] At present, the main synthesis method of α-hexyl cinnamaldehyde is the condensation of benzaldehyde and n-octyl aldehyde. Because the prices of both are relatively expensive, especially n-octyl aldehyde, the cost of the product α-hexyl cinnamaldehyde is relatively high, which is difficult to reduce.

Benzaldehyde and n-octyl aldehyde condensation reaction generally use alkali as catalyzer, and benzaldehyde easily takes place Cannizzaro side reaction under the action of alkali, has reduced the yield of product α-hexyl cinnamaldehyde; Although people have done a lot of improvements to this synthetic route liquid at present, For example, adding a phase transfer catalyst and adding a co-catalyst, but the current yield of α-hexylcinnamaldehyde is generally lower than 90%.

[0008] In summary, in view of the wide application of α-hexylcinnamaldehyde, its synthetic route is relatively simple and the yield is not very ideal. Therefore, it is necessary to develop a novel synthetic route at present, which can use cheap and easy-to-obtain raw materials as starting materials, which is simple and convenient. Synthesis of α-Hexylcinnamaldehyde with High Yield

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