  Electronic structure theory provides a foundation for understanding chemical
transformations and processes in complex chemical environments. Our work is
focused on the NWChemEx project that has selected two interrelated science
challenges that address the production of advanced biomass-derived fuels and
other value-added chemical compounds. One of which is the dehydration of
2-propanol over a zeolite catalyst. Aqueous phase dehydration of 2-propanol was
investigated using density functional theory (DFT) calculations. We considered
and analyzed the thermochemistry of the dehydration of 2-propanol using NWChem
calculations while the NWChemEx code is still under development. Realistically
modeling the reaction in this study properly requires simulations using
extended atomistic models. We validated our computational models by comparing
the predicted outcomes for 2-propanol dehydration with the calculated results
from 1-propanol dehydration studies. We used the first-principles DFT
calculations to investigate aqueous phase dehydration of 2-propanol, examine
the enthalpy of the 2-propanol reaction and computed the energy for geometry
optimization for increasingly better basis sets: cc-pVDZ, cc-pVTZ, cc-pVQZ,
cc-pV5Z, and cc-pV6Z. The various transition states and minima along the
reaction pathway are critical to inform the NWChemEx science challenge
calculations. In this work, we established how the accuracy of the calculations
depends on the basis sets, and we determined what basis sets are needed to
achieve sufficient accurate results. We also calculated the reaction free
energy as a function of temperature as thermodynamic parameter. We found that
at low temperature the reaction is thermodynamically unfavorable. Nevertheless,
dehydrating 2-propanol increases entropy, underscoring the need for high
temperatures to facilitate the reaction.
