Asymmetric Reduction Of Camphor By RaneyNi Catalyst Modified By D-tartaric Acid

Chiral compounds are important compounds,which are broadly used in perfume,medicine,pesticide,functional materials and so on.It has great importance to produce new method and new catalyst for chiral synthesis.There are two kinds chiral catalyst,homogeneous and heterogeneous phase catalyst.Homogeneous phase catalyst has high reaction activity and enantio-selectivity,but it's expensive and hard to reuse. Hetero-geneous phase catalysts are facile,easy operated and easy to reused, which are as green chemical catalyst.So it is important subject to develop new catalyst with high reaction activity and enantioselectivity.The system of Raney Ni modified by D-tartaric acid high reaction activity and enantio-selectivity on carbonyl compounds hydrogenation.Our subject trys to use RaneyNi/D-TA/NaBr as catalyst in hydrogenation of comphor.This is the main research contents:(1)Find new technical route. By read many abstract, we decide our technical route as this:research the effects of D-tartaric acid concentration,pH of modifying solution,selection of additives,temperature of modification and time of modification on Raney nickel catalyst.We find optimum modification conditions as: Raney Ni 3g, modified in 100ml solution with 1% D-tartaric acid concentration and 2% NaBr concentration,pH =4,which are achieved by adding1M NaOH,then modified 1hour at 100℃.(2)The influence of most important factors on the optical yield and hydrogenation activity varying the reaction temperature and pressure,solvent type,the reaction time and so on were systematically investigated.By many tests,We find optimum conditions as this:comphor 3g,modified Raney Ni 3g,ethanol-solution 500ml,acetoacetate2g,stirring speed as 800r/min,reaction10hour at 60℃.(3)Various physico-chemical methods,such as,infra-red spectroscopy (FTIR),X-ray diffractometry(XRD),scanning electron microscopy(SEM),BET surface area,and so on,were employed to gain a deeper understanding of the inherent problem of the factors effect.As a result, we found the loading amount of D-tartaric acid and crystal structure ware nearly same after hydrogenation,but Raney Ni surface became irregular,nickel atom dissolved.(4)To evaluate the mechanism of asymmetric hydrogenation of comphor, we consider many reference and our experimental data,and put forward chiral catalytic mechanism of RaneyNi/D-TA/NaBr system.