翻訳と辞書 |
Organic peroxide : ウィキペディア英語版 | Organic peroxide
Organic peroxides are organic compounds containing the peroxide functional group (ROOR'). If the R' is hydrogen, the compound is called an organic hydroperoxide. Peresters have general structure RC(O)OOR. The O−O bond easily breaks, producing free radicals of the form RO·. Thus, organic peroxides are useful as initiators for some types of polymerisation, such as the epoxy resins used in glass-reinforced plastics. MEKP and benzoyl peroxide are commonly used for this purpose. However, the same property also means that organic peroxides can either intentionally or unintentionally initiate explosive polymerisation in materials with unsaturated chemical bonds, and this process has been used in explosives. Organic peroxides, like their inorganic counterparts, are powerful bleaching agents.〔Herbert Klenk, Peter H. Götz, Rainer Siegmeier, Wilfried Mayr "Peroxy Compounds, Organic" in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. 〕 ==Properties== The O−O bond length in peroxides is about 1.45 Å, and the R−O−O angles (R = H, C) are about 110° (water-like). Characteristically, the C−O−O−R (R = H, C) dihedral angles are about 120°. The O−O bond is relatively weak, with a bond dissociation energy of , less than half the strengths of C−C, C−H, and C−O bonds.〔"A Reassessment of the Bond Dissociation Energies of Peroxides. An ab Initio Study" Robert D. Bach, Philippe Y. Ayala, H. B. Schlegel J. Am. Chem. Soc., 1996, volume 118, pp. 12758–12765. 〕 The oxidizing tendency of peroxides is related to the electronegativity of the substituents. Electrophilic peroxides are stronger O-atom transfer agents. For hydroperoxides, the O-atom donor tendency correlates with the acidity of the O−H bond. Thus, the order of oxidizing power is CF3CO3H > CH3CO3H > H2O2.
抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Organic peroxide」の詳細全文を読む
スポンサード リンク
翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|