Catalyst Screening through Quantum Chemical Calculations and Microkinetic Modeling: Hydrolysis of Carbon Dioxide

Renhu Ma, George F. Schuette, Linda J. Broadbelt*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Quantum chemical calculations are emerging as an effective way to screen catalysts for particular applications. In this contribution, we demonstrate the power of density functional theory to study CO2 hydrolysisby six carbonic anhydrase mimics, evaluating thermodynamic and kinetic parameters at the mechanistic level. A microkinetic model was then built based on the kinetics and thermodynamics calculated from first principles. The intrinsic reaction rate constant was calculated from the results of the microkinetic model and compared with experimental data. Overall, the rate constants were in good agreement with experimental values, except for zinc-tri and complex b, which were overestimated. This was ascribed to their ineffective complexation with Zn2+. How the reaction rate constants vary with time was also investigated. From 0 to 12 ms, the rate constants of complexes a and d decreased to 50 and 67% of their initial values, respectively; the rate constants of complexes b and f2 were almost invariant with time; the rate constant of complex f1 showed an unusual double sigmoidal shape. The pKa values of these six carbonic anhydrase mimics as well as three additional mimics were calculated. A correlation between pKa values and the binding free energy of OH-was obtained by fitting data from five zinc(II) aza-macrocyclic complexes. The reaction rate constants were found to increase linearly with the pKa value, indicating CO2 adsorption is the rate-limiting step.

Original languageEnglish (US)
Pages (from-to)949-960
Number of pages12
JournalTheoretical Foundations of Chemical Engineering
Volume51
Issue number6
DOIs
StatePublished - Nov 1 2017

Funding

ACKNOWLEDGMENTS The authors are grateful for the financial support provided by ConocoPhillips and Phillips 66.

Keywords

  • carbon dioxide hydrolysis
  • kinetic analysis
  • microkinetic modeling
  • quantum chemical calculations
  • zinc catalysts

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering

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