The Positional Effect of Solute Functional Group among Positional Isomers of Phenylpropanol in Hydroxyl Group-Solvent Specific Interactions in Methanol/Water Mixed Solvents Monitored by HPLC

Bulletin of the Korean chemical society

Joung Ho Ko¹  Won Jo Cheong¹  Gyoung Won Kang¹ 

关键词: Phenylpropanol;    Hydroxyl group;    Positional effect;    Specific interaction;   

DOI  :  

学科分类：化学（综合）

来源: Korean Chemical Society

【 摘 要 】

We have evaluated the hydroxyl group-solvent specific interactions by using a Lichrosorb RP18 stationary phase and by measuring the retention data of carefully selected solutes in 50/50, 60/40, 70/30, 80/20, and 90/10(v/v%) methanol/water eluents at 25, 30, 35, 40, 45, and 50 ^oC. The selected solutes are 3 positional isomers of phenylpropanol, that is, 1-phenyl-1-propanol, 1-phenyl-2-propanol, and 3-phenyl-1-propanol. There exist clear discrepancies in ツH^o (solute transfer enthalpy from the mobile to the stationary phase) and TツS^o (solute transfer entropy) among positional isomers. The difference in ツH^o and TツS^o between secondary alcohols (1- phenyl-1-propanol and 1-phenyl-2-propanol)is negligible compared to the difference between the primary alcohol (1-phenyl-3-propanol) and secondary alcohols. The TツS^o values of 3-phenyl-1-propanol are close to those of butylbenzene while the TツS^o values of secondary alcohols are close to those of propylbenzene. The difference in ツツH^o (specific solute-mobile phase interaction enthalpy) between the primary alcohol and the secondary alcohol decreases with increase of methanol content in the mobile phase. A unique observation is an extremum for 1-phenyl-3-propanol in the plot of TツツS^o vs. methanol volume %. The positive sign of TツツS^o of 3-phenyl-1-propanol implies that the entropy of 3-phenyl-1-propanol is greater than that of the hypothetical alkylbenzene (the same size and shape as phenylpropanol) in the mobile phase.

【 授权许可】

Unknown