核磁共振光谱法测定(S)-(-)-α-苯乙胺的对映体纯度

Determination of Enantiomeric Purity of (S)-(-)-α-phenylethylamine by NMR

以 (2R ,3R) 二苯甲酰酒石酸为手性溶解剂 ,用1HNMR的方法测定了 (S) (- ) α 苯乙胺样品的对映体纯度。以氘代氯仿为溶剂 ,当样品浓度为 0 0 5 1mol·L-1,手性溶解剂与样品的摩尔比为 0 33时 ,α 苯乙胺甲基双峰的化学位移不等价为 0 0 8ppm(基线分离 )。由甲基吸收峰的面积可以计算样品的对映体纯度。测量结果的相对标准偏差与样品的对映体纯度有关 ,当样品的ee值高达 99 1%时 ,RSD为 0 3 % (n =4)。

It was reported the determination of enantiomeric purities of (S) (-) α phenylethylamine by 1H NMR,using (2R,3R) dibenzoyl tartaric acid as chiral solvating agent. 1H NMR chemical shift non equivalence of the methyl doublet of α phenylethylamine was 0 08 ppm(base line separation) in solvent CDCl 3,when the concentration of the sample was 0 051 mol·L -1 ,the molar ratio between chiral solvating agent and the sample was 0 33.The enantiomeric purities could be determined by the peak areas of the methyl doublet of α phenylethylamine.The relative standard deviation depended upon the enantiomeric purities of sample.With enantiomeric purities as high as 99 1% ee ,the RSD was 0 3%( n =4).