摘要：

The axially chiral allenes dimethyl-1,3-allenedicarboxylate 1 and diethyl-1,3-allenedicarboxylate 2 show characteristic plateau formation during enantioselective GC separation on the chiral stationary liquid phase Chirasil--Dex. The elution profiles, obtained from temperature-dependent dynamic GC (DGC) experiments ( 1 : 100-140°C; 2 : 110-150°C) were evaluated with the recently derived approximation function (AF) to yield the enantiomerization rate constant directly k 1. These values were compared with those obtained by computer-aided simulation with ChromWin. The Eyring activation parameters of the experimental interconversion profiles were determined to be: G #(298.15 K) = 103.6 ± 0.9 kJ mol-1, H # = 44.7 ± 0.4 kJ mol-1, S # = -198 ± 7 J K1 mol-1 for dimethyl-1,3-allenedicarboxylate 1 , and G #(298.15 K) = 103.5 ± 1.1 kJ mol-1, H # = 44.7 ± 0.5 kJ mol-1, S # = -197 ± 9 J K-1 mol-1 for diethyl-1,3-allenedicarboxylate 2 . The approximation function (AF) presented here allows the fast determination of rate constants k 1 and activation barriers of enantiomerization G # from chromatographic parameters without extensive computer simulation. Chirality 14:465-470, 2002. 2002 Wiley-Liss, Inc.

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