Synthesis of spirosilicates directly from silica and ethylene glycol/ethylene glycol derivatives

Tetracoordinated spirosilicates have been synthesized directly from the reaction of a very inexpensive and plentiful material, SiO2, and ethylene glycol in the presence of triethylenetetramine (TETA), as catalyst with and without potassium hydroxide as co-catalyst. The reactions are run under nitrogen gas with constant stirring at 200°C, and complete in a reaction time of 10–18 h depending on the catalysts. The reactions using only TETA are complete in 18 h, while with potassium hydroxide the reactions occur much more quickly. When 3-amino-1,2-propanediol, or 2-amino-2-methyl-1,3-propanediol is employed, the reaction must run under vacuum at 0.1mmHg, 160°C, and is complete in 14 and 24 h, respectively. The structures of spirosilicates are fully characterized using FTIR, 1H, 13C, 29Si NMR, FAB+-MS, and TGA.