A Study On The Green Synthesis Process Of Isoeugenol Methyl Ether

Isoeugenol methyl ether is an important synthetic fragrance. It can be used as the fixing agent in making the flower-scent essence, such as carnation, rose, lilac, ylang ylang, etc. Isoeugenol methyl ether also can be widely applied to produce flavoring essence for daily use, food and tobacco.With the eugenol as starting materials and dimethyl carbonate as the reagent in methylation reaction, the eugenol methyl ether will be synthesized in nucleophilic substitution reaction. Consequentially, the isoeugenol methyl ether will be synthesized in isomerization reaction with alkaline conditions.Through considering the catalytic activity of different solid base catalysts in eugenol methylation reaction among the liquidoid batch, the KF has the best catalytic effect. Chosen KF as the catalyst, the better process conditions can be conducted through orthogonal test as follows:the reaction temperature is at 200℃, n(eugenol):n(DMC)=1:2.5, the amount of KF is 10% of the raw material, the reaction time is 5.5 hours. Under the above process conditions, the conversion rate of eugenol is 98.9%, and the yield of eugenol methyl ether is 94.9%.By choosing KOH and PEG-400 as the catalyst system and attempting one-step reaction to get isoeugenol methyl ether,the better process condition can be conducted as follows:the reaction temperature is at 200℃, n(eugenol):n(DMC)=1:2, m(KOH):m(PEG-400)=l:0.14: 0.06, the reaction time is 6 hours. Under the above process conditions, the conversion rate of eugenol is 97%, and the yield of isoeugenol methyl ether is 52%.An immobilized catalyst with the KOH/Y-Al2O3 as the carrier can be produced in pore volume impregnation (PV).Through considering the catalytic activity of the immobilized catalyst in the gas-solid reaction, KOH/y-Al2O3(15 wt%) is considered as the most suitable catalyst. When the KOH/y-Al2O3(15wt%) is used as the catalyst,the better process condition can be conducted as follows:the reaction temperature is at 300℃, the reaction pressure is 1MPa, the WHSV is 10 h-1,n(eugenol):n(DMC)=1:1.5.Under the above process conditions, the conversion rate of eugenol is 79%, and the yield of production in eugenol methylation reaction is 64%.Using liquid PEG-400 and solid PEG-400 as the phase transfer catalysts in isomerization reaction, the isoeugenol methyl ether can be produced under the solvent-free condition. When the liquid PEG-400 is chosen as the catalyst, the best process condition can be conducted through orthogonal test as follows:m(isoeugenol methyl ether,81%):m(Liquid PEG-400): m(KOH)= 1:0.16:0.12, the reaction temperature is at 90℃, the reaction time is 5 hours. When the solid PEG-400 is chosen as the catalyst, the best process condition can be conducted through orthogonal test as follows:m(isoeugenol methyl ether,81%):m(solid PEG-400): m(KOH)= 1:0.28:0.20, the reaction temperature is at 90℃, the reaction time is 5.5 hours.Under the above process conditions, the conversion rate of eugenol is 98.9%, and the yield of isoeugenol methyl ether is 94.9%. Under the above process conditions, the yield of isoeugenol methyl ether is 95.3%. The solid PEG-400 can be used as the catalyst about 8 times without any descend of the yield.