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利用Chiralpak AS-H手性色谱柱,以正己烷为流动相,以有机醇为极性改性剂,采用正相高效液相色谱法分别对乙草胺和异丙草胺的对映体进行了手性拆分,并结合紫外-可见、圆二色、旋光检测器和八区律规则对其对映体的绝对构型进行了判定。结果表明:乙草胺和异丙草胺的第一洗脱峰在220nm检测波长下均具有负的康顿(Cotton)效应和旋光(ORD)信号,根据八区律判定其构型为aR-型,具有相反信号的第二洗脱峰为aS-型。以正己烷-异丙醇(97∶3,体积比)为流动相时,乙草胺和异丙草胺分离度分别为2.23和1.52。其手性拆分过程均受焓驱动,且分子中的N-烷氧取代基在对映体与手性固定相作用过程中具有重要作用。
The enantiomers of acetochlor and isopropylamine were separated by Chiralpak AS-H chiral column with n-hexane as mobile phase and organic alcohol as polar modifier by normal-phase high performance liquid chromatography Chiral resolution was used to determine the absolute configuration of the enantiomers with UV-vis, circular dichroism, polarimetric detector and the rule of eight-zone law. The results showed that the first eluting peak of acetochlor and isopropylamine had a negative Cotton effect and an optical rotation (ORD) signal at the detection wavelength of 220 nm. According to the eight-zone law, the first elution peak was identified as aR- The second eluting peak with the opposite signal was aS-type. When n-hexane-isopropanol (97: 3, volume ratio) was used as mobile phase, the separation efficiencies of acetochlor and isopropylamine were 2.23 and 1.52, respectively. The chiral resolution process is driven by enthalpy, and the N-alkoxy substituent in the molecule plays an important role in the interaction between enantiomers and chiral stationary phases.