<i>In situ</i> small angle x-ray scattering, wide angle x-ray scattering, and Raman spectroscopy of microwave synthesis

Abstract

Recent studies in microwave chemistry have proven many enhancements in reaction rates and selectivities. Most dramatic are several zeolite syntheses where over an order of magnitude more rapid rates are often, but not always, found. The reasons for these enhancements are not understood in part because in situ spectroscopies under microwave exposure are problematic. Thus, techniques have been slow to develop. This study describes a novel system with which x-ray scattering and Raman studies can be performed in situ during exposure to microwave radiation. The mechanisms and rates for the syntheses of zeolites or other microwave syntheses can be studied dynamically in this manner. A 2.45GHz waveguide system operating in single pass or as a tuned cavity was developed through which an x-ray beam and/or a Raman laser could probe a synthesis solution and the appropriate scattering are studied. The X10A beamline at Brookhaven National Synchrotron Light Source was used for these studies.