Mechanisms of Hydrolysis鈥揙ligomerization of Aluminum Alkoxide Al(OC3H7)3
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- 作者：Xueli Cheng ; Yongjun Liu ; Dairong Chen
- 刊名：Journal of Physical Chemistry A
- 出版年：2011
- 出版时间：May 12, 2011
- 年：2011
- 卷：115
- 期：18
- 页码：4719-4728
- 全文大小：1347K
- 年卷期：v.115,no.18(May 12, 2011)
- ISSN：1520-5215
文摘
As one of the representative superinsulating materials, the aluminum trioxypropyl Al(OC3H7)3 aerogel may be applied in launch vehicles and manned spacecrafts. In this study, the structures and hydrolysis mechanisms of the monomer, dimers, and trimers of Al(OC3H7)3 in neutral and alkaline environments were studied at the B3LYP/6-31G(d,p) level by using the CPCM solvation model to understand the fundamental chemistry of Al(OC3H7)3 hydrolysis and oligomerization. Our calculation shows that the first-order hydrolyses of the monomer and oligomers are energetically favorable in both alkaline and neutral solutions. In alkaline solutions, they are more apt to oligomerize than to hydrolyze due to high energy barriers and large binding energies in the formation of anionic species. For the oligomers under neutral condition (1) Al(OC3H7)3 is linked by four-membered Al鈥揙 rings with pentacoordinated bridging and tetracoordinated Al atoms, (2) the hydrolyzed propoxy groups will be expelled by solvent molecules, and (3) partly hydrolyzed species can condense to oligomers with bridging OH groups or O atoms.