| Abstract
| - Despite the industrial importance of the process, the detailed chemistry of the high-temperature oxidation oftitanium tetrachloride (TiCl4) to produce titania (TiO2) nanoparticles remains unknown, partly due to a lackof thermochemical data. This work presents the thermochemistry of many of the intermediates in the earlystages of the mechanism, computed using quantum chemistry. The enthalpies of formation and thermochemicaldata for TiOCl, TiOCl2, TiOCl3, TiO2Cl2, TiO2Cl3, Ti2O2Cl3, Ti2O2Cl4, Ti2O3Cl2, Ti2O3Cl3, Ti3O4Cl4, andTi5O6Cl8 were calculated using density functional theory (DFT). The use of isodesmic and isogyric reactionswas shown to be important for determining standard enthlapy of formation () values for thesetransition metal oxychloride species. TiOCl2, of particluar importance in this mechanism, was also studiedwith CCSD(T) and found to have= −598 ± 20 kJ/mol. Finally, equilibrium calculations wereperformed to identify which intermediates are likely to be most prevalent in the high temperature industrialprocess, and as a first attempt to identify the size of the critical nucleus.
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