Study On New Method Of Synthesis Of 2-Methyl-3-(3, 4-methylenedioxyphenyl) Propanal

2-Methyl-3-(3,4-methylenedioxyphenyl)propanal is a kind of precious flavor with sweet and flower fragrance,which is widely used in concocting cyclamen,jasmine,lily of the valley,lilac,rose,and so on.In addition,it is also used as a component of cosmetic essence .Preparing of 2-Methyl-3-(3,4-methylenedioxyphenyl)propanal with safrole included two steps:synthesis of piperonal and synthesis of 2-Methyl-3-(3,4-methylenedioxyphenyl)propanal. synthesis of piperonal was consisted of safrole's isomerization and ozone oxidation. For traditional methods , isomerization reaction was done about 7h by using liquid alkali catalyst at 180℃.this methods have some problems ,such as low yields,high consumption of energy,seriously pollute. synthesis of 2-Methyl-3-(3,4-methylenedioxyphenyl)propanal included Claisen-Schmidt condensation of piperonal and propanal and hydrogenation of 2-Methyl-3-(3,4-methylenedioxyphenyl)acraldehyde. Claisen-Schmidt condensation have some difficulties in product separating,catalyst reclaiming. Hydrogenation reaction have also problems of low selectivity and yield. aiming at above problems, the paper mostly research preparing and applications of high performance green catalyst, adopting ozone oxidation etc advanced synthesis crafts .reaction conditions was optimized at above base in order to decrease product cost,increase yield and reduce pollute .isomerization reaction. Firstly using liquid PTC PEG-X and Polystyrene supported PTC PEG-X , isosafrole was synthesized in solvent-free conditions from safrole . the optimal conditions were obtained through orthogonal test. Namely, temperature 90℃, m(safrole,88.5%):m (KOH):m(PEG-X)=1:0.2:0.25,time 5h.under this conditions, the yields of isosafrole was 99.9%. though recycle use of Polystyrene supported PTC PEG-X was more than 10 times, its activity hadn't almost declined. the result of test showed that using PTC PEG-X could increase yields of isosafrole and decline temperature of reaction. in addition, the paper put forward base catalysis mechanism by discussing on isomerization mechanism of safrole.Ozone oxidation. Water was used as solvent, the optimum reaction conditions were obtained by orthogonal experiments ,yield of piperonal is 84.9%.Claisen-Schmidt condensation.by adopting strong base anion exchange resin ,avoiding side reaction of piperonal .in addition ,production was not only easy to be separated ,but also strong base anion exchange resin could recycle use. in some extent, this methods reduces pollution and decrease product cost,so it has definite industrial value. the optimum reaction conditions were obtained by orthogonal experiments: temperature 45℃,time6 h,m(piperonal):m(D201)=1:2.5,n(piperonal): n(propanal)=1:2,ethanol 7.5ml,yield is 78.5%. Hydrogenation reaction. firstly applying Pd/C catalyst modified Na₂CO₃ to hydrogenation of 2-Methyl-3-(3,4-methylenedioxyphenyl)acraldehyde, its yield is up to 91.6%.Under new conditions ,total yields of preparing 2-Methyl-3-(3,4-methylenedioxyphenyl)- propanal via isosafrole is 61.0%.its application effectively decreased product cost,reduced pollution,and increased yields of product.so it has industrial value partly.