[Rh(COD)Cl]_2催化剂的制备及催化α-蒎烯不对称加氢反应

Preparation of [Rh(COD)Cl]_2 catalyst and its activity for asymmetric hydrogenation of α-pinene

以RhCl_3·3H_2O和1,5-环辛二烯为原料制备了[Rh(COD)Cl]_2催化剂,并利用傅里叶变换红外光谱仪(FTIR)和X射线光电子能谱(XPS)对其进行了表征。以α-蒎烯加氢为探针反应,考察了COD/Rh摩尔比、回流温度及回流时间对催化剂催化性能的影响,并通过正交试验确定了催化剂适宜的制备条件:COD/Rh摩尔比(1,5-环辛二烯与三水合氯化铑摩尔比)3.5:1,回流温度75℃,回流时间3.5h。将该条件下制备的[Rh(COD)Cl]_2催化剂用于α-蒎烯加氢反应,α-蒎烯转化率达97.3%以上,顺式蒎烷对映选择性高于97.5%,顺式蒎烷收率达95.0%以上。与文献报道的其他工艺相比,该工艺特点是加氢条件比较温和,选择性高,催化效率高,能耗低。

[Rh（COD）Cl]2 catalyst was prepared by using RhCl3·3H2O and 1,5-cyclooctadiene as raw materials and characterized by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Taking α-pinene hydrogenation as a probe reaction,we investigated the effects of COD/Rh molar ratio,reflux temperature and reflux time on the catalytic properties. The suitable conditions for preparing the catalysts were proposed through orthogonal experiment,which were COD/Rh molar ratio of 3.5∶1,reflux temperature of 75℃ and reflux time of 3.5h. Then the conversion of α-pinene was above 97.3%,the enantioselective of cis-pinane was above 97.5% and the yield of cis-pinane was above 95.0%. Compared with other processes reported in the literature, the proposed process had features of mild hydrogenation conditions, high enantioselective,high catalytic efficiency and low energy consumption.