Structure of aggregates of alcohols studied by near-infrared and NMR spectrscopic measurements

用近红外(NIR)和核磁共振光谱研究了正构醇(正丁醇、正己醇和正辛醇)和不饱和醇(顺-9-十八烯-1-醇)在正庚烷和四氯化物溶液中在纯液体状态下的自缔合。无论溶剂的碳氢键长度和指数如何，正构醇的平均缔合度约为4。正构醇的缔合数高于与醇具有相同碳原子数的脂肪酸，这可能是正构醇粘度较高、自扩散系数较低的原因。顺-9-十八烯-1-醇(油醇)的缔合数小于正醇。这是由于其分子结构中含有顺式双键的空间位阻。对该系列烷烃进行了几乎完全的近红外光谱指认；烷烃在1450 nm处的吸收峰不是CH2，而是CH基。核磁共振弛豫时间研究表明，随着温度的升高，醇聚集体解离为单体分子。

The self-association of normal alcohols (1-butanol, 1-hexanol, and 1-octanol) and unsaturated alcohol (cis-9-octadecen-1-ol) in the pure liquid state in decane and in tetrachloride solutions has been studied by near-infrared (NIR) and NMR spectroscopic observations.The mean degree of association obtained for the normal alcohols is approximately four regardless of the hydrocarobon-chain length and inds of the solvent.The higher association number for the normal alcohols compared with that for fatty acids having the same nuber of carbon atoms as the alcohol most likely accounts for their higher viscosity and lower self-diffusion coefficient than those for the fatty acids. The association number for cis-9-octadecen-1-ol (oleyl alcohol) is less than that for normal alcohol. This is because of the steric hindrance of cis-type double bond included in its molecular structure.Almost perfect NIR band assignment in the spectrum were carried out for the series of alkanes ; the absorption band at 1450 nm for alkanes was concluded to be assigned not to CH_2 but CH groups. Relaxation-time study for NMR obviusly showed that the alcohol aggregates dissociate into monomeric molecules with an increase in temperature.