Thermochemical properties of pyrazine derivatives as seminal liquid organic hydrogen carriers for hydrogen storage

Abstract

This work contributes to our primary interest in applications of experimental and computational thermochemistry methods for providing the basic data required in chemical-process design. Pyrazine derivatives are considered as a seminal liquid organic hydrogen carriers. The standard molar enthalpies of vaporisation/sublimation of pyrazine derivatives were derived from the vapour pressure temperature dependences measured by the static and transpiration method. Enthalpies of fusion of the solid compounds were measured using DSC. Thermodynamic data on solid–gas, liquid–gas, and solid–liquid phase transitions available in the literature were collected and combined with own experimental results. We have evaluated and recommended the set of vaporisation and formation enthalpies of pyrazine derivatives at 298.15 K as the reliable benchmark properties for further thermochemical calculations. Gas phase molar enthalpies of formation of pyrazine derivatives calculated by the high-level quantum-chemical method G4 were in agreement with the recommended experimental data. Compilation of experimental and theoretical results derived in this work is useful for optimisation of hydrogenation/dehydrogenation reactions involved in the hydrogen storage technologies.