TIME-RESOLVED, IN-SITU X-RAY-DIFFRACTION STUDIES OF THE HYDROTHERMAL SYNTHESES OF MICROPOROUS MATERIALS

In this paper we describe the use of energy dispersive diffraction usi ng 'white' synchrotron radiation and angular dispersive X-ray diffract ion with a moving image plate detector to record time-resolved in situ diffraction data on a number of hydrothermal syntheses. We have studi ed the synthesis of an aluminophosphate, the open framework sulfide TM A-SnS-1, and the gallium fluorophosphate ULM-S, under hydrothermal con ditions. The effect of varying the temperature of reaction, reactant s ource and pH of solution on the syntheses has been investigated. Evide nce has been obtained that in cases where crystalline TMA-SnS-1 is for med, the reaction proceeds via an intermediate disordered lamellar pha se, before reacting further to form the final product. In the synthesi s of ULM-5 at least two intermediates have been observed. (C) 1998 Els evier Science B.V. All rights reserved.