Preparation of α-Quartz by the Thermal Degradation of Silicon Dioxide-Triethylamine(3/2)

Abstract

High purity a-quartz was prepared by calcination of silicon dioxide-triethylamine (3/2) at 1000 °C for 24 h in air.
Silico n dioxide-triethylamine (3/2) was obtained by the reaction of triethylamine and silicic acid in a tetrahydrofuran (THF) solution for 24 h at room temperature. The compound was confirmed to be 2(C₂H₅)₃N⋅3 SiO₂ by the elemental analysis, infrared specturm and the thermogravimetric analysis.
Impurity of sodium, potassum, iron and aluminium was not detected by atomic absorption analysys o f α-quartz synthesized, a no uranium as impurity was also detected by fluorescence analysis.
Reaction was considered as follows.
3H₄SiO₄+2 (C₂H₅)₃N→2(C₂H₅)₃N→3 SiO₂+6H₂O
2(C₂H₅)₃N→3 SiO₂+ 21_??_O₂→3 SiO₂₊ 12CO₂+15 H₂O+2NO₂