由异戊二烯合成月桂烯

Synthesis of Myrcene from Isoprene

研究了异戊二烯 (IP)在碱金属催化作用下均相线性二聚生成月桂烯的影响因素 ,得到最佳工艺条件 :反应温度 13℃ ,钠和钾各占一半组成的催化剂用量n(cat)∶n(IP) =(5～ 6 )∶10 0 ,二异丙胺的量n(DIPA)∶n(IP) =7∶10 0。对加入失活剂的反应液进行蒸馏处理 ,常压下回收溶剂和未反应的异戊二烯 ,质量分数分别大于 98%和 96 % ;在减压条件下分离出月桂烯 ,质量分数大于 90 %。回收的溶剂和异戊二烯可以再利用 ,以四氢呋喃作溶剂、二异丙胺作择形和阻聚剂时月桂烯的总收率大于 4 0 %。异戊二烯直接二聚合成月桂烯工艺简单 。

The selective linear dimerization of isoprene to produce myrcene in a homogeneous catalyst solution prepared by mixing the alkali metal,diisopropylamine(DIPA),the solvent and isoprene(IP) was studied.The optimum conditions of the dimerization of isoprene were obtained:t=13 ℃,sodium and potassium as constituents of catalyst, n (cat)∶ n (IP)=(5-6)∶100, n (DIPA)∶ n (IP)=7∶100 and tetrahydrofuran (THF) as solvent.Myrcene,unreacted isoprene and THF were separated form the reaction mixture by conventional distillations.The contents of recovered isoprene,THF and myrcene were respectively 96,98 and 90%.The recovered isoprene and THF were reused.Total yield of myrcene was over 40% when tetrahydrofuran was used as solvent,diisopropylamine as formation selecting agent and polymerization inhibitor.This process is simple and easy to be scaled up.