| 摘要 |
The invention relates to a continuous process for producing pseudoionones of general formulas (I) and (I.prime.) as well as isomers thereof, whereby: R1 represents CH3 or (a); R2 and R3 represent hydrogen, CH3 or C2H5, and; R4 an d R5 represent hydrogen or CH3. These pseudoionones are produced by reacting a n aldehyde of formula (II) with an excess of a ketone of general formula (III) , whereby R1, R2 and R3 have the aforementioned meanings, in the presence of water and alkali hydroxide at an increased temperature and in a homogeneous solution. The inventive process is characterized in that: a) the intermixing of the homogeneous solution consisting of aldehyde, ketone and aqueous alkal i lye occurs at a temperature ranging from 10 to 120 ~C; b) the undissolved water and alkali hydroxide contained in the reaction mixture are subsequentl y separated out; c) while avoiding back mixing, the homogeneous reaction mixtu re is then guided through a reactor, which permits a residence time ranging fro m 2 to 300 minutes, at a temperature that is 10 to 120 ~C higher than the boiling point of the lowest-boiling component and under a vapor pressure p ranging from 106 to 107 Pa; d) the reaction mixture is cooled by expansion; e) ketone is removed from the reaction mixture using vapor flowing in the opposite direction and; f) the raw product is dried and rid from excessive aldehyde and secondary components via a rectification column.
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