Infrared spectra have been recorded of the following mono-, di-, and tri-ethylene glycol monoalkyl ethers: CnH2n+1OCH2CH2OH where n = 17 and 19; CnH2n+1(OCH2CH2)2OH where n = 17, 18, 19, and 22; and C18H37(OCH2CH2)3OH. Spectra of the pure liquids, solutions in CCl4, and the solids at room and liquid air temperatures have been studied. From a study of the CH2 rocking modes at 927–934, 889, 900, and 862 cm−1 during the liquid–solid transformation and from solution studies, it has been shown that both the OCH2CH2O groups in diethylene glycol monoalkyl ethers exist predominantly in the gauche conformation in liquid and in solution. However, in the solid, while the end OCH2CH2O group takes both trans and gauche forms, the OCH2CH2O group adjacent to the polymethylene chain appears to take a trans configuration. The long polymethylene chain is found to pack in a triclinic subcell in the solid state, while in the quenched liquid state an orthorhombic or monoclinic packing is indicated. The present investigation has led to the conclusion that the difference in the conformations of end CH2CH2CH2OH groups found between the odd and even chain n-alcohols is removed in mono- and diethylene glycol monoalkyl ethers by the introduction of one or two OCH2CH2 groups.
记录了以下单、双、
三乙二醇单烷基醚的红外光谱:C
nH
2n+1OCH
2CH
2OH(其中n = 17和19);C
nH
2n+1(OCH
2CH
2)
2OH(其中n = 17、18、19和22);以及C
18H
37(OCH
2CH
2)
3OH。研究了纯液体、CCl
4溶液和室温和液态空气温度下的固体的光谱。通过在液态-固态转变期间观察927-934、889、900和862 cm
−1的CH
2摇摆模式以及溶液研究,表明双
乙二醇单烷基醚中的两个OCH
2CH
2O基团在液态和溶液中主要存在于 gauche构象。然而,在固态中,虽然末端的OCH
2CH
2O基团采取了反式和 gauche式两种形式,但靠近聚亚甲基链的OCH
2CH
2O基团似乎采取了反式构象。在固态中发现长聚亚甲基链在三斜晶亚胞中排列,而在淬火液态中则表明存在正交晶格或单斜晶格排列。本研究得出结论,通过引入一个或两个OCH
2CH
2基团,单
乙二醇单烷基醚和双
乙二醇单烷基醚中消除了奇偶链n-醇之间末端CH
2CH
2CH
2OH基团构象的差异。