乙酰丙酮氧钒催化氧化α-蒎烯一步转化成龙脑烯醛

One-step Conversion of α-Pinene to Campholenic Aldehyde via VO(acac)_2-catalyzed Oxidation

以乙酰丙酮氧钒为催化剂,过氧化氢为氧化剂,研究了由α-蒎烯直接合成龙脑烯醛的反应。考察了溶剂、温度、催化剂用量、反应时间等因素对催化性能的影响。结果表明,乙酰丙酮氧钒与H2O2反应得到的高价态V5+是优良的氧化还原-Lewis酸双功能催化剂,易使α-蒎烯经氧化、2,3-环氧蒎烷异构得到龙脑烯醛。在n(H2O2):n(α-蒎烯):n(乙酰丙酮氧钒)=2.5:1:0.01、反应温度为20℃、丙酮为溶剂、反应2h条件下,α-蒎烯转化率为50.2%,龙脑烯醛的选择性达58.7%,反应6h后α-蒎烯转化率可达73.0%,主要产物龙脑烯醛和马鞭草烯酮的选择性分别为47.2%和13.2%。

Conversion of α-pinene to campholenic aldehyde was directly carried out with aqueous hydrogen peroxide as oxidant catalyzed by VO（acac）2.The effects of reaction conditions such as solvents,temperature,dosage of catalyst and time on this reaction were investigated.The results showed that high valent V5＋ obtained from VO（acac） 2 and H2O2 is a good redox-Lewis acid bi-functional catalyst for the transformation of α-pinene to campholenic aldehyde via oxidation and isomerization of 2,3-epoxy pinane intermediate.Under optimal reaction conditions of n（H2O2）：n（α-pinene）：n（VO（acac） 2） = 2.5：1：0.01,reaction temperature 20 ℃,using acetone as solvent,58.7% selectivity of campholenic aldehyde was achieved at 50.2% conversion of α-pinene after 2 h reaction.Reacting for 6 h under the conditions described above,conversion of α-pinene can reach up to 73.0% and selectivity of major products campholenic aldehyde and verbenone were 47.2% and 13.2%,respectively.