Prediction of high temperature hydrodeoxygenation reaction equilibria of phenol to benzene via reaction ensemble Monte Carlo simulations

Reaction ensemble Monte Carlo simulations in the isothermal isobaric ensemble have been performed to study the thermodynamics of gas phase hydrodeoxygenation of phenol to benzene (C6H5OH+H2⇁↼ C6H6+H2O) using continuous fractional component Monte Carlo (CFCMC) approach via Brick-CFCMC open source software package. We have explored the use of single-site and two-site models for H2, with TraPPE-EH force field to describe the interactions present in phenol and benzene, and TIP4P water model. Simulations have been performed at elevated temperatures from 973.15–1273.15 K, and at 1 bar. Equilibrium mole fraction of benzene (and consequently, equilibrium conversion of phenol) reduces with increase in temperature. From our simulations, ln⁡K values are greater than unity in the temperature range 973.15 K to 1073.15 K, between zero and unity at 1123.15 K and 1173.15 K, and negative at the two highest temperatures (i.e. 1223.15 K and 1273.15 K), showing qualitative agreement with literature reported data. The slope of ln⁡K vs 1/T estimated from our simulations result in negative standard heat of reaction (ΔH0), further confirming exothermic nature of the reaction. Our Rx/CFCMC simulations with both H2 models yield similar values of equilibrium mole fractions of benzene, conversion of phenol and ln⁡K over entire elevated temperature range.