EFFECT OF FLUORIDE IONS ON CRYSTALLIZATION OF TITANIUM SILICALITE

Fluoride ions were introduced into the synthesis of titanium silicalite TS 1 and the effect of fluoride ions on the crystallization of TS 1 was systematically studied The synthesis using TPABr and NH 4F exhibits the similar phenomenon with the synthesis using TPABr and BuNH 2 etc Seeds can be added to reduce the crystal size of TS 1 and the crystal size of TS 1 increases with the decrease of the amount of NH 4F when the NH 4F/SiO 2 ratio lies at the range of 0 25 to 1 0 When the TPABr / SiO 2 ratio lowers to 0 025, the crystallinity of TS 1 will reduce largely The smallest amount of TPABr needed in the crystallization is about TPABr / SiO 2 = 0 025～0 05 The crystallinity of TS 1 increases with the increase of SiO 2/TiO 2 Fluoride ions can improve the crystallization of titanium silicalite The crystallinity of TS 1 will exceed 70% in one day if fluoride ions were introduced into the TPABr BuNH 2 system But chlorine ions do not have the same effect