SYNTHESIS OF FIBROUS TITANIUM SILICALITE (FTS-1) ZEOLITE

Fibrous titanium silicalite (FTS-1) zeolite has been prepared from tit anium silicalite (TS-1) particles that were less than 120 nm in diamet er. The formation of FTS-1 was mainly affected by the particle size of the TS-1 zeolite. FTS-1 is formed by both capillary force and dehydro xylation among the TS-1 particles during the drying and evaporation pr ocess of the dispersed TS-1 particles in aqueous solution. The average length and the aspect ratio (length/diameter) of FTS-1 are 2.2 and mm 50 similar to 70, respectively. The obtained FTS-1 shows a two-dimens ionally aligned surface that is affected by the treatment of dispersed TS-1 particles in aqueous solution. Si-29 MAS n.m.r. spectra showed t hat the concentration of the hydroxyl group on the surface of TS-1 par ticles was decreased after the formation of FTS-1 and was reduced cont inuously up to 750 degrees C with calcination. This suggests that the condensation reaction of hydroxyl groups on the surface of TS-I partic les occurs by drying and heat treatment. After calcination at 750 degr ees C, FTS-1 still exhibited characteristics of MFI-type structure wit h orthorhombic symmetry. It showed distinctive secondary pores due to the aggregation of TS-1 particles. This method of FTS-1 formation may suggest a new method for the preparation of various types of zeolites. (C) Elsevier Science Inc. 1997.