笔者以α-蒎烯为原料高选择性环氧化合成2,3-环氧蒎烷。探讨了过氧乙酸浓度及用量、碳酸钠用量、溶剂类型、反应温度及反应时间等对α-蒎烯转化率、2,3-环氧蒎烷选择性及产物组成的影响;确定了适宜的环氧化反应条件:反应温度为0~10℃;过氧乙酸浓度2.0 mol/L,α-蒎烯与过氧乙酸物质量之比为1∶1.1;α-蒎烯与碳酸钠物质量之比为1∶1.2;反应时间2 h;以氯仿为溶剂,溶剂用量为α-蒎烯与氯仿体积比1∶1.7。在此条件下α-蒎烯转化率为99%以上,2,3-环氧蒎烷的选择性大于95%,反应产物中主要杂质α-龙脑烯醛和3-蒎酮的含量仅为3.3%和1.2%左右。
2,3-epoxypinane was synthesized from α-pinene by epoxidation with high selectivity.Effects of concentration and dosage of peracetic acid,dosage of anhydrous sodium carbonate,solvent types,reaction temperature and reaction time on the conversion of α-pinene were investigated,respectively.Mean while the selectivity of 2,3-epoxypinane and chemical compositions of the products were investigated too.The most suitable reaction conditions were finally determined as follows: temperature 0-10 ℃,concentration of peracetic acid 2.0 mol/L,molar ratio of α-pinene and peracetic acid 1∶1.1,molar ratio of α-pinene and Na2CO3 1∶1.2,reaction time 2.0 h,using CHCl3 as the solvent and volume ratio of α-pinene and CHCl3 1∶1.7.At this condition,conversion rate of α-pinene was above 99%,selectivity of 2,3-epoxypinane was more than 95%.The contents of the main impurities α-campholenic aldehyde and 3-pinonic in the final product were only 3.3% and 1.2% respectively.