Structure and Thermal Behavior of Water Dissolved in Ethers Studied by FT-IR Spectroscopy

Kyo TAKAOKA*, Koichi KOBAYASHI, Masashi TAKAHASHI, Yasunori TARU†, Masahisa TAKASAGO† and Mototaka SONE††

Department of Energy Science and Engineering, Faculty of Engineering, Musashi Institute of Technology; 1-28-1 Tamazutumi, Setagaya-ku, Tokyo 158-8557 Japan
† Center of Educatinal Reseach, Faculty of Engineering, Musashi Insutitute of Technology; 1-28-1 Tamazutumi, Setagaya-ku, Tokyo 158-8557 Japan
†† Department of Electrical and Electronics Engineering, Faculty of Engineering, Musashi Institute of Technology; 1-28-1 Tamazutumi, Setagaya-ku, Tokyo 158-8557 Japan

The states of dissolved water in various ethers such as diethyl ether(DEE), dipropyl ether(DPE), dibutyl ether(DBE) di-s-butyl ether(DSBE), dioctyl ether(DOE), didecyl ether(DDE) and ethylene glycol dibutyl ether[1,2-dibut-oxyethane(DBOE)] were studied by FT-IR spectroscopy. Also, thermal stability was examined for water clusters formed in such ethers.
The water cluster consists of [-O-·H2O], and [-O-·Cluster], the small clusters(C1 and C2) and the large clusters(LC1, LC2 and LC3). The water molecules in [-O-·H2O] interact with the oxygen atom of ether group through hydrogen bonding, and are surrounded by [-O-·Cluster]. The C1 and C2 are formed in the free volume among alkyl chains, and LC1, LC2 and LC3 exist around C1 and C2.
As the negativity on oxygen atom of ether group becomes greater with increasing alkyl-chain length of the ethers, [-O-·Cluster] becomes larger. The amount and the size of Cl and C2 are decreased with increasing alkyl-chain length of the ethers, while those of the large cluster (LC1, LC2 and LC3) are increased.
In the range from 40 °C to 80 °C, the Cl are vaporized and finally C1 disappears. LC2 and the LC3 are gradually divided into smaller clusters with increasing temperature.


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