Solvent effect in the chromatographic enantioseparation of 1,1'-bi-2-naphthol on a polysaccharide-based chiral stationary phase.
Enantioseparation of 1,1'-bi-2-naphthol (BINOL) was performed on a polysaccharide-based chiral stationary phase, Chiralcel OD-H, under normal-phase mode. The effects of polar modifier in the mobile phase on the retention, enantioseparation and elution order were investigated in detail. Solvent-induced reversal of elution order for BINOL was observed. When linear alcohols were adopted, R-BINOL was always eluted first. S-BINOL was eluted first when 2-propanol was used as a polar modifier. Enantioseparation could not be obtained when sec-butyl alcohol or tert-butyl alcohol was used as a polar modifier. When isoamyl alcohol or cyclohexanol was used as a polar modifier, favorable enantioseparation was obtained as with 1-pentanol or 1-hexanol; also, R-BINOL was the first-eluted enantiomer. It is worth emphasizing that significantly better enantioseparation was obtained when higher alcohols were used as polar modifier of the mobile phase. A nonlinear characteristic for the lnalpha against 1/T plots was universally observed in this study though the lnk against 1/T plots exhibited a linear feature. Associated with the obtained thermodynamic parameters, some interesting inferences about chiral recognition mechanism were proposed.
Zhan
Fengping
F
Department of Chemistry and Environmental Science, Zhangzhou Normal University, Xiangcheng District, Zhangzhou 363000, China.
Yu
Guangyan
G
Yao
Bixia
B
Guo
Xueping
X
Liang
Ting
T
Yu
Minggen
M
Zeng
Qingle
Q
Weng
Wen
W
D002845:Chromatography / Q000295:instrumentation* / Q000379:methods; D009284:Naphthols / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry*; D013237:Stereoisomerism; D013816:Thermodynamics
D009284:Naphthols; D011134:Polysaccharides; D012997:Solvents; C412332:1,1'-bi-2-naphthol