POLIMORFO DELLA SILICE E PROCEDIMENTO PER LA SUA PREPARAZIONE

摘要

A new silica polymorph exhibiting a similar X-ray powder diffraction pattern to Zeolite ZSM-5 is produced by inclusion of phosphate or sulphate ions in the silica so reaction mixture which is refluxed or autoclaved. The polymorph exhibits improved thermal stability and an absence of an infrared adsorption band at a wave number of 700 cm<-1>.