Synthesis of titanium silicalite-2 (TS-2) from methylamine-tetrabutylammonium hydroxide media

Titanium silicalites have been synthesized by new procedures using hydrogen fluoride-methylamine media. X-ray diffraction has revealed that the products were identical to TS-2 with the MEL structure. Titanium ions were incorporated into the zeolite framework, as confirmed by X-ray powder diffraction (XRD, unit cell expansion), infrared (IR) and ultraviolet-visible (UV-Vis) spectroscopies. The presence of hydrogen fluoride as a co-mineralizer in the gel can improve the crystallization. Increasing the amount of methylamine in the gel is led to a remarkable incorporation of titanium in the MEL framework. The advantage of these methods is the use of cheaper sources (Ti and Si) than those used in a conventional method; but the amount of titanium incorporated into the TS-2 lattice via the new methods is different. For different titanium containing TS-2 samples catalytic conversions, selectivities and yields in the hydroxylation of benzene with hydrogen peroxide were different. (C) 2004 Elsevier B.V. All rights reserved.