Preparation of titania from tetrakis(diethylamino)titanium via hydrolysis

The conversion of tetrakis(diethylamino)titanium (Ti(NEt₂)₄) into titania via either a combination of hydrolysis (Ti(NEt₂)₄:THF:H₂O = 1:10:x, x = 2, 4, 10) at ambient conditions and calcination (method A) or hydrolysis in a water-tetrahydrofuran (THF) mixture (Ti(NEt₂)₄:THF:H₂O = 1:10:100) at reflux (method B) was investigated. Titanium tertiary butoxide (Ti(O^tBu)₄) was also used as a substitute for Ti(NEt₂)₄. The hydrolysis via method A resulted in the formation of amorphous solids containing organics. Thermal analyses showed that the hydrolysis products showed mass losses up to 500°C probably due to the presence of diethylamine (Et₂NH) formed via the hydrolysis of Ti(NEt₂)₄ in the hydrolysis products, while a mass loss of the hydrolysis product from Ti(O^tBu)₄ was completed up to about 200°C. After calcination at ≥600°C, anatase or a mixture of anatase and rutile was obtained. The crystallization behavior of the hydrolysis products from Ti(NEt₂)₄ was different from that of the hydrolysis product from Ti(O^tBu)₄. The hydrolysis via method B gave only an amorphous material from Ti(NEt₂)₄, while a crystalline titania (anatase and brookite) formed from Ti(O^tBu)₄.