(334bu) Image Processing for Detecting Two Dimensional Distribution of Granules' Properties That Are Produced in Twin Screw Granulation
The generation of acid site solvent models was applied to modeling ethanol dehydration in H-Al-Beta at conditions near intrapore condensation of water. Clusters of six water molecules were found to be stable at reaction temperatures (373 K). To study the coadsorption of ethanol and water at active sites to form reactive intermediates, free energies of adsorption were calculated from AIMD including the translational entropy of adsorbates. We found that ethanol adsorption displaces one water from a water-alkanol cluster to form a solvated ethanol monomer (C2H5OH)(H+)(H2O)5. The solvated bimolecular dehydration transition state was then simulated with metadynamics-biased AIMD. The solvated transition state is stabilized at the periphery of the water cluster, with the non-polar ethyl groups excluded from the solvation environment. This insight explains why the penalty to solvate the transition state is not incurred until water coverages surpass the size of stable clusters in experiments. We can then predict how different micropore geometries control solvation during catalysis.