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Preparation and crystallinity of a large unsubstituted crown ether, cyclic heptacosa(oxyethylene) (cyclo-E27, 81-crown-27), studied by Raman spectroscopy, X-ray scattering and differential scanning calorimetry

DOI: 10.1039/ft9969203173

Source and publish data:

Journal of the Chemical Society - Faraday Transactions p. 3173 - 3182 (1996)

Update date:2022-08-02

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Authors:

Yang, ZhuoYang, Zhuo

Yu, Ga-ErYu, Ga-Er

Cooke, JenniferCooke, Jennifer

Ali-Adib, ZiadAli-Adib, Ziad

Viras, KyriakosViras, Kyriakos

Matsuura, HiroatsuMatsuura, Hiroatsu

Ryan, Anthony J.Ryan, Anthony J.

Booth, ColinBooth, Colin

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Article abstract of DOI:10.1039/ft9969203173

Cyclic heptacosa(oxyethyelene) (cyclo-E27, 81-crown-27) was prepared from linear α-hydro, ω-hydroxy-heptacosa(oxyethylene) by reaction with tosyl chloride under alkaline conditions, purified by preparative-scale gel permeation chromatography, and studied by laser-Raman spectroscopy, wide-angle and small-angle X-ray scattering, and differential scanning calorimetry. Comparison was made with the properties of linear oligo(oxyethylene) dimethyl ethers (including C1E27C1). The sub-cell of the crystalline cyclic oligomer was the same as that of its linear counterparts, i.e. the same as that of high-molar-mass poly(oxyethylene). However, the cyclic oligomer crystallised as a twice-folded ring, as confirmed by its long spacing and the frequency of its single-node longitudinal acoustic mode (LAM-1). Enthalpies of fusion and melting temperatures were analysed to provide estimates of the enthalpy and entropy of formation of a fold in an oligo(oxyethylene) layer crystal.

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Product name:α-hydro, ω-hydroxyheptacosa(oxyethylene)

Cas No:28780-45-2

28780-45-2

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