Study On The Synthesis Of Styrallyl Acetate

Styrallyl acetate is a kind of important ester perfume which was widely used in flavor and fragrance industry. Because of its strong volatile odour which smells like gardenia, it can be used for preparing not only daily fragrance of jasmine, hyacinth, lily, lilac or magnolia, but also edible essences of apple, pineapple, apricot, plum, or peach which needs the "sharp" flavor of fruit. It’s the main feedstock for daily fragrance of gardenia or tuberose scent. The traditional synthesis method is firstly preparing methyl benzyl alcohol by hydrogenation of acetophenone, and then generating styrallyl acetate by esterification of acetic oxide. As the decreasing production of acetophenone in recent years, the price of raw materials rises and the cost is being seriously challenged. Besides, the traditional process conditions have some shortcomings of complicated procedure and high corrosive to devices which is a certain influence on environmental contamination. Nowdays green chemistry is more accepted because of the increasingly environmentally conscious of human being which makes one-step synthesis of styrallyl acetate by atomic economic reation have great importance.One-step synthesis of sryrallyl acetate from styrene and acetic acid catalyzed by green catalyst is an atomic economic reation with simple steps and characterized by its high selectivity rate which meets the requirement of green chemistry. The remaining raw materials can be recycled to save resources which shows a very bright industrial prospect.First, the reaction system and mechanism of synthetizing styrallyl acetate from styrene and acetic acid by catalyst is studied. By establishing the kinetic reaction model, the possible mechanism can be proved and excluded.Second, the green catalyst of synthesis system is studied. The catalyst with a better reactivity can be found by screening the Lewis acid catalysts. The optimum reaction condition can be obtained by means of single factor tests and orthogonal tests as followed, the reaction time is8hours, the reaction temperature is120℃and the amount of lanthanum bromide as the catalyst is5(mass fraction) percent of styrene. On such conditions, the yield and selectivity rate of styrallyl acetate can be reached to95%and90%. This system is characterized by mild reaction conditions, high selectivity rate. The remaining raw material can be recycled, which meets the requirement of green chemistry.Third, the recycle tests of catalyst is designed and the yield of styrallyl acetate shows no significant decline by5times recyclic regeneration.Last, styralyl propionate is synthetized and the optimum reaction condition is obtained by means of single factor tests as followed, the reaction time is8hours, the reaction temperature is110℃and the amount of lanthanum bromide as the catalyst is2.8(mole fraction) percent of styrene. On such conditions, the yield and selectivity rate of styralyl propionate can be reached to90%and82%.