Study On Synthesis Myrcene And Its Allylamine

Myrcene is one of important spice flavors and pharmaceutical intermediates. At present, one ofthe key issues for the chemical synthesis of myrcene is that the cost of its raw materials and catalystare too high. The solution method to this problem has great significance in the chemical synthesis ofmyrcene. In this dissertation, we study on myrcene and its allylamine which are the intermediates of l-menthol prepared by a new method. The dimerization of isoprene to formate myrcene shows thepotential applications for its cheapness and wide isoprene. Meanwhile, N,N-diethylnerylamine issynthesized by n-butyl lithium catalyzed myrcene and diethylamine. They are obtained from thedimerization of isoprene in the reaction, aimed at providing some technical supports for synthesis ofmyrcene by chemical synthesis methods. The findings and conclusions of our work in this dissertationare as follows:Firstly, the dimerization of isoprene is formated myrcene in the presence of diidopropylamineand the alkali metal. The optimum process conditions is obtained as:11%(molar ratio to isoprene, thesame below) of sodium metal,8%diisopropylamine at30℃for40min, and the yield is about38%.Based on the above, we study the process conditions for two other alkali metals as initiators that arelithium and potassium. And8%lithium,11%diisopropylamine at80℃for6h, the yield obtained isabout13%. As for potassium, the condition is that5%potassium,7%diisopropylamine at20℃for45min, and the yield of myrcene is about50%. The strong metallic calcium, magnesium andaluminum are investigated simulaneously as the initiators, the impact on the synthesis of myrcene isfound that isoprene can’t be activated to polymerize into myrcene by these three metals.Secondly, we combined the study on the influence of alkali metal in the process of isoprenepolymerizing into myrcene, the possible reaction mechanism of synthesis of myrcene is proposed.The possible mechanism of synthesis of myrcene is that: firstly, sodium and amine are combined toform the amine sodium compounds, and then a small amount of isoprene with amine sodiumgenerates isoprene sodium free radicals to continue the reaction of myrcene. And it is found thatsecondary amines have the inhibitory effect of high polymer of isoprene.Finally, two kinds of cis and trans isomers of N, N-diethyl-3,7-dimethyl-2,6-octadiene-1–amine are synthesized, which are N,N-diethylgeranylamine and N,N-diethylnerylamineTwo isomers are rapid detected by GC, and then N,N-diethylnerylamine is “one pot”synthesized via n-butyl lithium catalyzed isoprene and diethylamine. The optimum processconditions is obtained as: under a certain pressure, the volume ratio n(IP): n(DEA)=4.5:1–5.0:1,and V(IP): V(n-BuLi)=4:1, reaction temperature is70℃, reaction time is13h., N, N-diethylneryl- amine base amine is obtained, which is the cis structure of N, N-diethyl-3,7-dimethyl-2,6–octadiene-1-amine, and the yield of N,N-diethylgeranylamine is also relatively small.