| Heliotropine is a kind of flower-perfume spiceries. It adapts to various sorts of fragrance adjustment. Raw materials to produce heliotropine are safrole oil and dihydroxybenzene . Most countries including China use safrole oil. Because many new kinds of tree containing sassafras have been developed and planted currently, forests being destroyed in large scale can be avoided. Safrole oil is nowadays and will be still the main raw material for heliotropine manufacture.Because catalyzation method with potassium hydroxide has merits of cheap material and simple technique , it becomes the sole method to produce isosafrole in domestic factories. However, it has defects of low yield rate ( less than 90% ) and large amount of waste water . Because of low degree of water pollution, ozone-oxidation has become the dominating method to oxidize isosafrole. Nevertheless, the process is complicated and yield of heliotropine (less than 85%)needs to be improved.The factors affecting safrole isomerization were studied and the optimized conditions are that mass ratio of potassium hydroxide solution (50%) to sassafras is 0. 04 , temperature is 200掳C, vacuum is 0. 06MPa, time is 2 hours. The optimal yield of isossafrole is 83. 97%. Isomerization in this method needs high temperature and spends much energy. The reaction brings out low yield, produces great deal of sewage , and results in serious water pollution. Meanwhile, this method doesn't adapt to safrole oil with low concentration.Solid potassium hydroxide was used instead of its solution , ambient pressure instead of vacuum and mechanic agitation instead of nitrogen agitation. Optimized conditions are obtained: temperature is 150掳C, mass percentage of solid potassium hydroxide is 2%, agitation velocity is 150rpm, reaction time is 3. 5 hours. The optimal isosafrole yield is 96. 04%. Isomerization in this method brings ideal yield and spends less energy . It produces little sewage and the degree of water pollution is small. This way of isomerization adapts to safrole oils with both high and low concentration.Using solid potassium hydroxide with nitrogen stir under low vacuum condition is another method for isomerization. The optimized conditions are that temperature is 140 , mass percentage of solid potassium hydroxide is 2%, vacuum is 0.03 MPa, reaction time is 1.5 hours. The optimal isosafrole yield is 96. 89% . The reaction result is quite ideal , while reaction temperature is lower, time is apparently shortened and sewage is much lessened. This way adapts to safrole oils with high concentrations as well as low ones. It was found that, if air was used instead of nitrogen, the yield would consequently be very low.With water as diluent in isosafroie ozone-oxidation and ozone-oxide aftertreatment, some side-reactions were studied. The optimized conditions are obtained that ozone-oxidation temperature is 10 , mass ratios of potassium and water to isosafroie oil are 0.03 and 4 respectively, ozone-oxide is washed one time , concentration of sodium metabisulfite solution is 10 %, mass ratio of sodium metabisulfite solution to isosafroie oil is 2.5 .hydrolysis temperature is 95 , hydrolysis time is 30 minutes, sodium carbonate solution is dosed at 55 till pH value is 11. The optimal heliotropine yield is 86.2%.Water and xylene were used as a mixed diluent . The optimized conditions are obtained by orthogonal experiments : mass ratios of water, xylene and potassium hydroxide to isosafroie oil are 4, 1 and 0.03 respectively, ozone-oxidation temperature is 5 , ozone-oxide is washed one time, hydrolysis temperature is 95 , temperature for dosing sodium carbonate solution is 55, after dosing sodium carbonate pH value of solution is 11. The optimal yielding rate of heliotropine is 87. 4 %. It was found that , if water amount was too low, ozone-oxidation temperature would run up rapidly , which was liable to result in explosion.Parallel experiments were made in heliotropine crude distillation. Conclusion is conducted that, to obtain more quantity and more conten...
|
PDF Full Text Request