| Popis: |
The heat of formation of benzophenone oxide, Ph2CO2, was measured using photoacoustic calorimetry. The enthalpy of the reaction Ph2CN2 + O2 Ph2CO2 + N2 was found to be −48.0 ±0.8 kcal mol−1 and ΔHf(Ph2CN2) was determined by measuring the reaction enthalpy for Ph2CN2 + EtOH Ph2CHOEt + N2 (−53.6 ±1.0 kcal mol−1). Taking ΔHf(PhCHOEt) = −10.6 kcal mol−1 led to ΔHf(Ph2CN2) = 99.2 ± 1.5 kcal mol−1 and hence to ΔHf(Ph2CO2) = 51.1 ± 2.0 kcal mol−1. The results imply that the self-reaction of benzophenone oxide i.e., 2Ph2CO2 2Ph2CO + O2 is exothermic by −76.0 ±4.0 kcal mol−1. |
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