A Research To The Synthesis Of Lemonile By Dehydration With Base-catalysis

Lemonile is a new kind of perfumery,It possesses a perfect quality of perfume and doesno stimulation ad irritability to the skin0 Thus it is safe in using and permitted by U.S.RLFM for external use0Being a synthetic Perfumery,Lemonile is widely used in cosmetics,soap and washings as essence with fruitllke, flowerlike and woodlike fragrancy0There are two main steps in making of the lemonile 0 The first step is to take citraloxime from the citral and then the second is to make lemonile from the citraloxime by dewatering with (CH3CO)200A great deal of work had been done before in making the lemonile,nevertheless,there are obviously some unsolved problems 0 That is , the synthetic rate of lemonile from citral was too low and great amoumt of (CH3CO) 20 was used up in the procession of dewatering 0 Thus the cost was too expensive 0 In order to solve these problems , three tasks are to be done as followed:I The improvement of the pre~'ious work0Based on the analysis of the mechanism in forming citraloxime and dewatering citraloxime acetate,we improved the reaction conditions and raised the productive rate of citraloxime up to 92.2 % (the content is 95.1 %) and the inversion rate from citraloxime to lemonile up to 92.7 % (the content of th two main isomers is up to 94.5 %) 0 So the synthetic rate from citral to lemonile is increased greatly0II The research of the most optimal reacting condition of synthesizing lemonile by dehydrating with the phase transfer Base catalysis of citraloxime0Based on the analysis of the previous achievements and the features of the E2 elimination reaction, We defined that the base catalysis dehydration of citraloxime in toluene solution as E2 elimination reaction0 And we successfully accelerated the reaction speed between liquid and solid phase by applying phase transfer catalyst( PTC) and increased the conversion percentage of lemonile from citraloxime 0 And then We identified the optimal condition of dehydration by the way of orthogonal experimental desigh.That is:The quantit) in using of KOH is 15% and that of the tetrabutylammonium Bromide is 6% (according to the percentage of mole Based on citraloxirne) The temperature of reaction is 110-il 2t, and the time is ~ And under these conditions conwrsional percentage of lemonile from citraloxime is 9 1.0% (the content of the two main isomers is 96.0 %)~In apllying of this proccess,the amount of KOH and TBAB is smaller and the toluene can be reused, Furthermore,it is easy to handle and offers good prospects0ilL THe initial application of carrier-base KOH/A1203 to study the function of base catalysis dehydration of citraloxime0Benefiting by the application of inorganic carrier reagent in the organic synthesis,we make a series of carrier-Base KOHIAI2O3 and use them to dewater the citraloxime into lemonile0 And then the orthogonal experimental design is used to define the optimal de hydration conditions:The quantity in use of 1:1.2 KOH}A1203(the mole ratio) is 20 % (the mole percentage of KOH to citraloxime)0 The temperature of reaction is 110-I 12C and the time is 3.0h0 In these conditions, the average inversion rate of lemonile from citraloxime is up to 94.1 % (the content of the two main isomers is up to 94.6 %)~In practice, only a small amount of KOHIAhO3 is used, and the Carrier Al203 and the toluene can be reused The conversion rate is high in this proccess and it has a hopefulindustrial prospect0...