A method for synthesizing γ, δ-unsaturated ketones

Abstract

The invention discloses a method for synthesizing a gamma, delta-nonsaturated ketones compound. The method comprises the following steps: under protection of inert gas, nonsaturated alcohol and 2-alkyloxy propylene are taken as the raw materials, Bronsted acid functional ionic liquid is dissolved in a high boiling solvent as a catalyst, a rearrangement reaction is carried out, after the reaction is complete, the materials is subjected to post-treatment to obtain the gamma, delta-nonsaturated ketones compound and a catalyst solution. The used Bronsted acid functional ionic liquid catalyst has a plurality of physical and chemical properties which are similar with the conventional ionic liquid, the acid functional group is introduced, so that the catalyst has the advantages of high acid site density, adjustable acidity, uniform acidity distribution and difficult loss of acidity. An autoclave series mode is used for realizing the continuous synthesis of nonsaturated ketone and continuous recycling of the catalyst.

Description

technical field [0001] The invention relates to a method for preparing gamma, delta-unsaturated ketones from unsaturated alcohol and 2-alkoxypropylene, which belongs to the field of fine chemical industry. Background technique [0002] γ, δ-unsaturated ketones, the structure of which is shown in formula (I), specifically including the improvement of methyl heptenone, geranyl acetone and farnesyl acetone and their derivatives, is a synthetic plant Alcohols, major intermediates of vitamins E and K [Catalysis Today 121(2007) 45–57]. [0003] [0004] Among them, R is C 1 ~C 11 alkyl. [0005] At present, the synthesis methods of γ, δ-unsaturated ketones mainly include the following types: (1) the reaction of allyl alcohol or propargyl alcohol with acetoacetate or diketene to form a new acetoacetate after Carroll re- Arrange to generate β-keto acid, and then naturally decarboxylate to generate carbon dioxide and product unsaturated ketone [J.Am.Chem.Soc.65 (1943) 1992-199...

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Problems solved by technology

However, the universality of this type of ionic liquid catalyst is low, as the reaction described in the text is mainly limited to the reaction of acetylenic alcohols

The catalyst is less efficient in catalyzing the rearrangement reaction of enol rearrangement, which may be due to the higher temperature and stronger acidity of enols than acetylene alcohols in the Saucy-Marbet reaction. After the rearrangement of catalyzed acetylenic alcohols, the acid loss is serious, the catalytic efficiency is greatly reduced, the number of applications is reduced, the cost of catalysis is increased, and industrial production is not used

[0012] The contriver finds, when sulfonic acid and phosphoric acid catalyst catalyze above-mentioned reaction, because acidity is stronger, easily produce the by-product of unsaturated alcohol dehydration, as the by-product of methyl butenol, this by-product and excessive 2 in the raw material -Alkyl propylene has a similar boiling point and is not easy to separate, resulting in difficulty in recovery and increased cost. When catalyzed by weak acids such as substituted phosphoric acid and sulfonic acid pyridinium salt, the reaction time is too long, resulting in the product being mixed with excess vinyl ether and acetone Side reactions occur, reducing the reaction yield, and the catalyst cannot be recycled

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