Atomistic Simulations of Structural Defects and Water Occluded in SSZ-74 Zeolite

The amount and location of water trapped during the synthesis of pure silica SSZ-74 has been predicted by atomistic simulations, and the results are in agreement with XRD as well as 1 H and 29 Si MAS NMR previously published data of the material. With SSZ-74 being the first zeolite in which structural defects have been fully characterized by XRD and MAS NMR, we have completed a new force field parametrization which allows the possibility of simulating silanol and siloxy groups with improved accuracy, as well as water and the organic structure directing agents. The results of the simulations show that water is present in the as-made material, a fact not fully analyzed in the original characterization of the SSZ-74. Further, we find the amount and location of water as well as the structure of the defects and characterize the interaction of water and the defects. The computational results show a reasonable agreement with the experimentally reported data.