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目的:采用气相色谱法拆分扁桃酸甲酯对映体,并通过对映体分离过程中的热力学参数计算,探讨扁桃酸甲酯对映体分离过程中的驱动力及其拆分机理。方法:在β-环糊精(CyclodexB)手性毛细管柱上分离扁桃酸甲酯对映体。结果:在柱温为118℃,载气流速为1mL·min-1时,扁桃酸甲酯对映体在β-环糊精(CyclodexB,30m×0.25mm×0.25μm)手性毛细管柱上具有较好的分离效果,其分离因子(α)和分离度(R)分别为1.02和1.55。扁桃酸甲酯对映体lnk′与1/T和lnα与1/T之间具有较好的线性关系。并从VantHoff曲线求得(R)-扁桃酸甲酯和(S)-扁桃酸甲酯焓变(ΔH)分别为-59.29kJ.mol-1和-60.64kJ·mol-1,两者的焓变差[Δ(ΔH)]和熵变差[Δ(ΔS)]分别为-1.34kJ·mol-1和-3.25J.mol-1.K-1。结论:扁桃酸甲酯对映体的拆分过程主要是一个焓控过程,且β-环糊精外表面与扁桃酸甲酯之间的相互作用在其分离过程中起了重要作用。
OBJECTIVE: To separate the enantiomers of methyl mandelate by gas chromatography and to study the driving force and mechanism of enantioseparation of mandelate by means of thermodynamic parameters during enantioseparation. Methods: Enantiomers of methyl mandelate were separated on a β - cyclodextrin (CyclodexB) chiral capillary column. Results: The enantiomers of methyl mandelate had the following properties on a β-cyclodextrin (CyclodexB, 30m × 0.25mm × 0.25μm) chiral capillary column at a column temperature of 118 ℃ and a carrier gas flow rate of 1mL · min-1 A better separation effect, the separation factor (α) and resolution (R) were 1.02 and 1.55. There was a good linear relationship between lnk ’of mandelate and 1 / T and lnα and 1 / T. The enthalpy change (ΔH) of (R) -mandelate and methyl (S) -mandelate were -59.29kJ.mol-1 and -60.64kJ · mol-1, respectively, from the VantHoff curve, The variation [Δ (ΔH)] and entropy variation [Δ (ΔS)] were -1.34 kJ · mol-1 and -3.25 J.mol-1K-1, respectively. CONCLUSION: The resolution of methyl mandelate is mainly enthalpy control. The interaction between β-cyclodextrin and mandelate plays an important role in the separation process.