Study On The Optimization Of Synthesis Process Of Lily Aldehyde

Lily aldehyde is the most important raw material for making lily flower fragrance.At present,the annual demand of lilac is over 20000 tons.At present,there are many methods for synthesizing Lily aldehyde,but each method has its own shortcomings.Therefore,it is necessary to continue to study a process route with simple process,high yield,low cost,easy disposal of three wastes,and suitable for industrial production.In this paper,4-tert-butyl benzaldehyde was used as raw material,and first,p-tert-butyl methyl cinnamaldehyde was prepared by condensation of n-propanal with aldol.By screening the catalyst system,optimizing the reaction parameters,and adjusting the post-treatment scheme,a highly efficient catalyst system was finally obtained.The catalyst can be recycled,avoiding the production and treatment costs of the three wastes,and the reaction conversion rate and yield are greatly improved.The best process.conditions we had choosed are as follows:the amount of the catalyst potassium hydroxide is about 2.0%～2.2%(w/w)of the amount of 4-tert-butyl benzaldehyde,and the molar ratio of 4-tert-butyl benzaldehyde to propionaldehyde we used is 1:0.9,methanol as the solvent,it’s amount is 1.5eq.The reaction temperature is 20～30℃,the droplet time of propionaldehyde is 3.0 h～4.0 h,and the holding time is 0.5～1.0 h.with this condition,the yield of 4-tert-butyl benzaldehyde can reach about 95.0%,with the scrap rate is 2.5%,and after the crystallization process,we can get the product content over99.50%Then,through hydrogenation,using palladium carbon as catalyst and suitable catalyst,the tert-butyl methyl cinnamaldehyde was hydrogenated to produce the product-libell-aldehyde.By screening the catalyst system and optimizing the reaction parameters,the hydrogenation catalyst is recycled,greatly optimizing the reaction yield and reducing the cost of the raw material.The selectivity of the hydrogenation reaction is over 99.0%,with the yield is more than 98.0%,and the whole yield of the two steps is more than 93.1%.The purity of the finished product of the lily aldehyde is high,the aroma is pure and no impurity,and the top indexes all meet the requirements of the commercially available products.The optimum process conditions are as follows:2%palladium carbon catalyst is 0.6%,cocatalyst triethylamine is 1.5%,solvent is used as 2.0～2.5 times of raw material,reaction temperature is 60℃,reaction time is 2.5 h.The selectivity of Lily aldehyde is more than 99.0%,the yield is more than 98.0%,and the scrap rate is about 1.0%.The purity of the obtained Lily aldehyde is more than 99.00%,the aroma is pure and no impurity,and the various indexes meet the requirements of the commercially available products.The innovation of the process is that the high-efficiency condensation and hydrogenation catalyst system is screened,the yield is greatly improved,the condensation catalyst is stably applied,the generation of the three wastes is avoided,the catalyst cost is reduced,and the post-treatment process is optimized.The recovery solvent and the rectification process of the conventional condensation step are avoided,the energy consumption cost is reduced,it is conducive to industrial scale production.The shortcoming of this paper is that the research results stay in the small test stage,and industrial production has not yet been carried out.The stability of the process and the conclusion of the small test require verification of the later production commissioning to further supplement the data.