Dihydromyrcene Process Of Synthesis Of Citronellyl

Citronellol is a perfume with an odor of sweet rose, and it is a popular constituent of odorants for soap and cosmetics and a fragrant agent for foodstuff, and possesses higher additional value.On the perfume industry at present, citronellol is prepared from oil of citronellal and geraniol. The subject of this research is to sythesize citronellol from diliydromyrcene. This method is not reported in internal newspapers yet.There are two methods to derive citronellol from dihydromyrcene. One method is the hydroboration - oxidation method, and anothers is the peroxidation - the saponification method.The hydroboration-oxidation method is that dihydromyrcene is treated with diborane to yield tricitronellyl boron, and the tricitronellyl boron then is oxidized and hydrolyzed in a hydrogen peroxide and sodium hydroxide aqueous solution to producethe desired alcohol-citronellol. The concrete contents studied are: Finding out theoptimum temperature of the reaction by changing the reaction temperature as hydroboration of dihydromyrcene, then finding out the optimum quantities of the oxidant by changing the quantities of the oxidant as tricitronellyl boron being oxidized and hydrolyzed. According to the results of the above experiments, explores the optimum conditions of the reactions and the best yield of sythesizing citronellol. Through above experiments, claim that:1. The optimum temperature of the reaction of diborane and dihydromyrcene is at temperatures between about 25℃ and 30℃. The best yield of tricitronellyl boron reaches 46.5% and its selectivity reaches 65.6%.2. The best amount of the oxidant is above 80% of tricitronellyl boron whentricitronellyl boron is oxidized and hydrolyzed in hydrogen peroxide and sodiumhydroxide aqueous solution. The best yield of citronellol reaches 97.5% and itsselectivity reaches 100%.3. The best yield of citronellol that is produced by the hydroboration-oxidation method reaches 46.5% and its selectivity reaches 65.6%, and the citronellol are all beta forms.4. Diborane can be prepared with potassium borohydride instead more expensive sodium borohydride, followed being carried out the reation of hydroboration with dihydromyrcene. But the quantities of potassium borohydride must be excessive.The peroxidation-saponification method is that dihydromyrcene carries on Markownikow addition reaction with anydrous hydrogen chloride to yield 2-chloro-2,6-dimethyl-7-octene ,then 2-chloro-2,6-dimethyl-7-octene carries out anti-Markownikow addition reaction with anydrous hydrogen bromide in the presence of benzoyl peroxide to produce 2-chloro-8-bromo-2,6-dimethyl-7-octane. And citronellyl ester (mixture of alpha and beta forms) is readily obtained by heating 2-chloro-8-bromo-2,6-dimethyl-7-octane with the salt of carboxylic acid. Among the above reaction, the chlorine atom of the 2-chloro-8-bromo-2,6-dimethyl-7-octane is consumed, and the bromine atom of the 2-chloro-8-bromo-2,6-dimethyl-7-octane is replaced at the same time. Citronellyl ester finally carries out the saponification reactionin alkali solution to produce the desired alcohol-citronellol. The concrete contentsstudied are: finding out the optimum temperature of the reaction that by changing the reaction temperature in the chlorination reaction with hydrogen chloride, then finding out the optimum reactions conditions in the bromineization reaction by changing temperature of the reaction as well as quantities of catalyzer, next rinding out optimum, of agent by using different sorts of agent during the reaction becoming the ester and consuming, finally in the saponification reaction , finding out the optimum amounts of sodium hydroxide by changing quantities of sodium hydroxide . According to the results of the above experiments, explore the optimum conditions of the reactions and the best yield of sythesizing citronellol. Through above experiments, claim that:1. The optimum temperature of the reaction of anydrous hydrogen chloride and dihydromyrcene is at temperatures between ab...