Four different silica end members of zeolites (zeosils) namely silica-ZSM-48, silica ZSM-22, silica-ferrierite and silica-ZSM-5 have been synthesized and their structural features and properties determined. Long chain polyamines act as templates for the formation of silica-ZSM-22 and silica-ZSM-48. The use of amines with side NH2 groups or straight chain amines at elevated temperatures, favours the formation of silica-ZSM-48. Ethylenediamine-boric acid pair acts as a template for silica-ferrerite formation while the use of highly branched tertiary mines leads to the formation of silica-ZSM-5. Available data indicate that these four zeosils are isostructural with the corresponding zeolites. These molecular sieves contain 3-dimensional 4-connected network of corner linked [SiO4] tetrahedra, possessing channel like voids. Silica-ZSM-22 and silica-ZSM-48 contain 1D channel systems but the latter has wider channels. Silica-ferrierite possesses 2D channels while silica-ZSM-5 possesses a 3D channel system. All these frameworks are thermally stable upto 10000C, even after the removal of templates. They are hydrophobic, organophyllic and possess neither catalytic nor ion exchange properties.
How to Cite:
Gunawardane, R.P., 1988. Studies on some novel silica molecular sieves. Journal of the National Science Foundation of Sri Lanka, 16(2), pp.159–173. DOI: http://doi.org/10.4038/jnsfsr.v16i2.8248
Gunawardane, R P. “Studies on some novel silica molecular sieves”. Journal of the National Science Foundation of Sri Lanka, vol. 16, no. 2, 1988, pp. 159–73. DOI: http://doi.org/10.4038/jnsfsr.v16i2.8248