Preparation Of Metal Alkoxide Preparation

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Sol-gel process is convenient synthetic approach for preparation to metal oxide applied in a wide variety of fields including structural ceramics [1, 2], electronics [10, 11], sensors [3–5], optics [8, 9], and catalysts [6, 7] due to their hardness, high melting point, non-volatility, chemical inertness, and resistance to oxidation and corrosion [1-4]. The sol-gel method is based on phase transformation of a sol obtained from metallic alkoxides or molecular modified alkoxide. The suspended particles in the sol are polymerized at low temperature to form a wet gel [16-19]. Metal alkoxide, being the good precursors in sol-gel process, is purified by vacuum distillation or crystallization and addition pure water yields the metal oxide with high purity and the volatile by-product. A great advantage of this method of oxide preparation is in its absence of ionic impurities [20]. Despite being widely applied, the chemistry of the sol-gel synthesis utilizing metal alkoxide precursors is hardly understood. …show more content…

The enhanced reactivity of metal alkoxides towards hydrolysis, or nucleophilic attack requires precautions and adaptations when used as precursors for sol–gel processing. The higher reactivity towards nucleophilic attack is caused by the lower electronegativity and resulting higher Lewis acidity of the metals and therefore depends on the type of metal, viz. its electronegativity. Metal alkoxides are much stronger Lewis bases and the acidity of water is strong enough to achieve their rapid hydrolysis via proton-assisted SN1 pathway even in the absence of additional

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