申请人:BASF Aktiengesellschaft
公开号:US06300524B1
公开(公告)日:2001-10-09
The present invention relates to an improved process for preparing higher unsaturated ketones by reacting the corresponding &agr;,&bgr;-unsaturated alcohols with alkyl acetoacetates in a Carroll reaction , in a reactor system with fitted fractionation column, wherein
A the &agr;,&bgr;-unsaturated alcohol is introduced into the reaction vessel together with the organic aluminum compound in the absence of effective amounts of a solvent, and the alkyl acetoacetate is metered into this mixture,
B a reaction temperature which is as constant as possible at between 175° C. and 220° C., preferably between 180° C. and 200° C., is adjusted and
C during the reaction the content of alkyl acetoacetate in the reaction mixture is adjusted to a value which is as constant as possible at between 1 and 3% by weight.
It is advantageous in this process for the reaction temperature defined under B to be controlled by suitable variation of the heat input and/or by variation of the rate of addition of the alkyl acetoacetate, and for adequate mixing of the reaction mixture in the reaction vessel to be ensured This can be achieved with the aid of a stirrer, by pumping the reaction mixture through an external liquid circulation, by introducing the alkyl acetoacetate by means of a mixing nozzle or else by passing in a stream of inert gas.
The process according to the invention is particularly suitable for the Carroll reaction of higher alcohols such as 3,7-dimethyl-1,6-octadien-3-ol (linalool), 3,7-dimethyl-1-octen-3-ol, 3,7,11-trimethyl-1,6,10-dodecatrien-3-ol (nerolidol), 3,7,11-trimethyl-1-dodecen-3-ol or 3,7,11-trimethyl-1,6-dodecadien-3-ol (dihydronerolidol).
本发明涉及一种改进的方法,通过在带有分馏柱的反应器系统中,将相应的α,β-不饱和醇与乙酰乙酸烷基酯在Carroll反应中反应,制备出更高不饱和酮。其中:
A. α,β-不饱和醇与有机铝化合物一起在无溶剂的情况下引入反应器中;
B. 调整反应温度,尽可能保持在175℃至220℃之间,最好在180℃至200℃之间;
C. 在反应过程中,将乙酰乙酸烷基酯的含量调整到尽可能保持在1%至3%之间。
在这个过程中,通过适当改变热量输入和/或乙酰乙酸烷基酯的加入速率来控制B中定义的反应温度,并确保在反应器中充分混合反应物。可以通过搅拌器、通过外部液体循环泵送反应混合物、通过混合喷嘴引入乙酰乙酸烷基酯或者通过惰性气体流入来实现。本发明的方法特别适用于更高级别的醇的Carroll反应,例如3,7-二甲基-1,6-辛二烯-3-醇(芳樟醇)、3,7-二甲基-1-辛烯-3-醇、3,7,11-三甲基-1,6,10-十二烷三烯-3-醇(纳罗利醇)、3,7,11-三甲基-1-十二烯-3-醇或3,7,11-三甲基-1,6-十二二烯-3-醇(二氢纳罗利醇)。