Preparation of citral
AssigneeBASF SE
InventorsAxel Nissen, Walter Rebafka, Werner Aquila
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Abstract
Citral (I) ##STR1## is prepared by heating an acetal (IIa) or (IIb) ##STR2## in the presence of an acid catalyst while continuously distilling from the reaction mixture the 3-methylbut-2-en-1-ol (III, prenol) eliminated during the reaction.
Claims4
In a process for the preparation of citral (I) ##STR10## by heating an acetal of the formula IIa or IIb ##STR11## in the presence of an acid catalyst, the improvement which comprises carrying out the reaction at 100.degree.-160.degree. C. in the presence of 0.1-10 mole%, based on IIa or IIb, of an inert liquid IV, which under the reaction pressure boils at a higher temperature than 3-methyl-but-2-en-1-ol (III, prenol) but at a lower temperature than citral, 2,8-dimethyl-5-oxa-nona-1,3,7-triene (V) and 2,4,4-trimethyl-3-formyl-hexa-1,5-diene (VI) while continuously distilling off the prenol eleminated in the reaction over a fractioning column, at the top of which a pressure of 40-140 mbar is maintained.
Dependencies are inferred from the claim text.