The standard enthalpy of formation of 1,3,5,7-tetramethyl-2,4,6,8-tetrathiaadamantane

Abstract

A description of the Stirling thermochemical laboratory is given along with details of the macro aneriod rotating-bomb calorimeter. A convenient analytical procedure has been established to ascertain the final state present in the calorimeter after the combustion of organosulphur compounds. The standard enthalpy of combustion of 1,3,5,7-tetramethyl-2,4,6,8-tetrathiaadamantane has been measured. The value ΔH c o(C 10H 16S 4,c) = −(2026.1 ± 0.6) kcal th mol −1 yields a standard enthalpy of formation ΔH f o(C 10H 16S 4,c) = −(36.8 ± 0.7) kcal th mol −1. The standard enthalpy of sublimation has been measured as ΔH sub o(C 10H 16S 4,c, 298.15 K) = (28.0 ± 1.0) kcal th mol −1. The corresponding gas-phase enthalpy of formation is ΔH t o(C 10H 16S 4,g) = −(8.8 ± 1.2) kcal th mol −1. The thermodynamic properties of 1,3,5,7-tetramethyl-2,4,6,8-tetrathiaadamantane at 298.15 K have been calculated.