PROPERTIES OF [TI,AL]-BETA WITH DIFFERENT TITANIUM CONTENT

Crystallization curves of [Ti,Al]-Beta were obtained from reaction mix tures having Si/Ti ratios between 20 and 125 and Si/Al approx. 200. It was observed that practically all aluminum is incorporated into the s olid during the first hours of reaction, whereas titanium and silicon are continuously incorporated. Increasing Ti content in the reaction m ixture results in an increase in particle size, indicating that the pr esence of Ti reduces the nucleation rate. X-ray diffraction and diffus e reflectance spectra show that when the Ti content is less than 4% of the tetrahedral atoms, this element is incorporated in the sieve fram ework in isolated form. (C) Elsevier Science Inc. 1997.