α-蒎烯经二溴莰烷合成冰片二烯

Synthesis of the Bornadiene from 2,6-Dibromocamphane

以α-蒎烯为原料与Br2进行加成、异构化反应合成2,6-二溴莰烷,以2,6-二溴莰烷为中间体制备冰片二烯。α-蒎烯合成2,6-二溴莰烷的条件:Br2和α-蒎烯为2.5∶1(物质的量之比),反应温度为0℃,反应时间24 h,反应溶剂为二氯甲烷,此条件下α-蒎烯转化率为97.6%,定向转化为2,6-二溴莰烷的选择性最高(48.8%)。提纯后的2,6-二溴莰烷纯度为99.0%,得率为45.6%。以提纯后的2,6-二溴莰烷为原料制备冰片二烯的适宜反应条件:反应温度100℃,反应时间5 h,叔丁醇钾为消除试剂,叔丁醇钾与2,6-二溴莰烷投料比4∶1(物质的量比),DMF为溶剂。2,6-二溴莰烷转化率为99.12%,冰片二烯的选择性为99.0%,提纯后的冰片二烯纯度可达98.5%。采用FT-IR、GC-MS和1H NMR等方法对2,6-二溴莰烷和冰片二烯进行了结构鉴定。

This article states the preparation of bornadiene from 2,6-dibromocanmaphane.It was synthesized from Br2 and α-pinene by addition and isomerization reactions.In this study,α-pinene was used as raw material for synthesis of 2,6-dibromocamphane.The production processes have been improved.The optimal conditions were： mole ratio of Br2 to α-pinene 2.5 ∶ 1,reaction temperature 0 ℃,and reaction time 24 h.The conversion rate of α-pinene reached 97.6 %,2,6-dibromocamphane selectivity of 48.8 %,yield 45.6 %.Self-made 2,6-dibromocamphane was used to synthesize bornadiene.The optimal conditions were as follows： reaction temperature 100 ℃,reaction time 5 h,t-BuOK used as elimination reagent,the mole ratio of t-BuOK to 2,6-dibromocamphane was 4 ∶ 1,conversion rate of α-pinene reached 99.12 %.FT-IR,GC-MS,1 H NMR and elemental analysis were used to identify the structure of 2,6-dibromocamphane and bornadiene.