- Method for preparing 2,4-heptadienal
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The invention discloses a method for preparing 2,4-heptadienal. Heptadienal is prepared by taking propyl aldehyde as a starting material through the following three reaction steps: (1), synthesizing acrolein diethyl acetal through absolute ethyl alcohol and anhydrous calcium chloride; (2), synthesizing 1,1,3,5-tetraethoxyheptane through acrolein diethyl acetal, BF3 diethyl ether and vinyl ether; and (3), synthesizing trans-2-trans-4-heptadienal through 1,1,3,5-tetraethoxyheptane and hydrochloric acid. The method disclosed by the invention has the beneficial effects that raw materials are easily obtained, and cheap; a condition is easily controlled and operated; and, the product is relatively low in cost and better in quality, and is suitable for large-scale production.
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Paragraph 0011; 0013
(2017/08/28)
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- Preparation of Methine Homologues of Aldehydes and Carboxylic Acids
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Dilithium salts of carboxylic acids add to glyoxal mono(dimethylhydrazone) (5) to give salts of β-hydroxy carboxylic acids.Reaction with tosyl chloride affords via decarboxylation the corresponding unsaturated aldehyde hydrazones 10 or 15, which are easily hydrolyzed and oxidized to form unsaturated carboxylic acids.By this method aldehydes and/or carboxylic acids may be extended by one methine group.Extension by three methine groups can be achieved with vinylogous monohydrazones such as 23.
- Zimmermann, Birgit,Lerche, Holger,Severin, Theodor
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p. 2848 - 2858
(2007/10/02)
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