SYNTHESIS AND CHARACTERIZATION OF TITANIUM SILICALITE TS-1 PREPARED USING PHOSPHONIUM IONS

Titanium silicalites with the MFI structure have been synthesized usin g binary mixtures of tetrabutyl-phosphonium hydroxide (TBPOH) and tetr aethylphosphonium hydroxide (TEPOH). Whereas the MEL structure was obt ained with pure TBPOH, addition of TEPOH led to a modification of the structure, and TS-1, with the MFI structure, was obtained. The crystal s had a specific habit, similar to that of standard TS-1 crystals. The ir size decreased with the Ti content in the zeolite. A maximum Ti inc orporation of about 1.35 wt% could be achieved following this synthesi s route. X-ray diffraction, u.v.-vis, and i.r. spectroscopies have sho wn that the zeolites thus obtained possessed all the structural charac teristics of TS-1. C-13 end P-31 solid-state n.m.r. revealed that both TBP+ and TEP+ cations were introduced into the structure.