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Structural Chemical Study of Nonionic Surfactant-Water Systems by Vibrational Spectroscopy

通过振动光谱法研究非离子表面活性剂-水体系的结构化学

基本信息

批准号：
03640427
负责人：
FUKUHARA Koichi
金额：
$ 1.28万
依托单位：
HIROSHIMA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03640427/
关键词：
Nonionic Surfactants Conformation Vibrational Spectroscopy コンホメ-ション

项目摘要

For elucidation of various characteristics of binary systems of alkyloxyethylene nonionic surfactants and water, properties of the hydrophilic oxyethylene chain play an important role. In particular, the conformational behavior of the oxyethylene chain is one of the important factors for understanding the structure of the system. Accordingly, in this year of 1992, conformational behavior of noncyclic and cyclic oxyethylene chains was studied in detail. The model compounds used are alpha-methyl-omega-methoxyhexakis(oxyethylene) and 18-crown-6, respectively. By utilizing infrared spectroscopy in combination with normal coordinate calculations, hydration and conformational states of the oxyethylene chain were examined in an extensive concentration range. Conformation of the OC-CO group was elucidated on the basis of changes of the hydration structure. With addition of water to neat liquid, the gauche conformation of the OC-CO group is more stabilized with the formation of bridged hydrogen bonds between the ether oxygens of the oxyethylene unit and water molecules. The distance between the oxygens of the gauche OC-CO group is about 0.28 nm. This distance is, however, too short for a single water molecule to form a stable bridged hydrogen bond, but may be adequate to stabilize the gauche structure through proton-lone pair interactions.In this year, another study was also performed on polymorphic behavior of C_<16>E_3, which is one of the typical alkyloxyethylene nonionic surfactants. Changes in crystallinity and conformation with phase transformations were elucidated by Raman spectroscopy. This polymorphic phenomenon is closely related to the structure of various mesophases formed by nonionic surfactants in aqueous solution.

在研究烷氧基非离子表面活性剂与水二元体系的各种性质时，亲水性烷氧基链的性质起着重要的作用。特别是，oxidoresin链的构象行为是理解系统结构的重要因素之一。因此，在1992年的这一年里，我们详细地研究了非环状和环状氧化物链的构象行为。所用的模型化合物分别是α-甲基-ω-甲氧基六烷基（oxidase）和18-冠-6。通过利用红外光谱结合正常的坐标计算，水合和构象状态的oxidesperin链在一个广泛的浓度范围内进行了检查。根据水化结构的变化，阐明了OC-CO基团的构象。通过向纯液体中加入水，OC-CO基团的扭曲构象更加稳定，在氧杂环单元的醚氧和水分子之间形成桥接氢键。OC-CO基团的氧之间的距离约为0.28 nm。然而，这个距离对于单个水分子形成稳定的桥连氢键来说太短了，但通过质子-孤对相互作用可能足以稳定该结构<16>。通过拉曼光谱阐明了结晶度和构象随相变的变化。这种多晶型现象与非离子表面活性剂在水溶液中形成的各种中间相的结构密切相关。