Knowledge of a Molecule: An Experimental and Theoretical Study of the Structure and Enthalpy of Formation of Tetrahydro-2H-1,3-oxazine-2-thione
Roux, M. V.[MarIa Victoria], Temprado, M.[Manuel], Jimenez, P.[Pilar], Notario, R.[Rafael], Parameswar, A. R.[Archana R.], Demchenko, A. V.[Alexei V.], Chickos, J. S.[James S.], Deakyne, C. A.[Carol A.], Liebman, J. F.[Joel F.]
In a continuation of our investigations of the thermochemistry of heterocyclic ring systems and sulfur-containing compounds, the standard molar enthalpy of formation of tetrahydro-2H-1,3-oxazine-2-thione (CAS no. 17374-18-4) at T = 298 K has been evaluated both experimentally and computationally. Combined enthalpies of combustion and sublimation, measured by rotary bomb combustion calorimetry and the Knudsen effusion technique, yielded a gas-phase enthalpy of formation of -(104.0 +- 5.5) kJ*mol 1. The G3 value of -104.6 kJ*mol 1 calculated using an isodesmic bond separation reaction is in excellent agreement with the experimental result. The variation in enthalpy of formation with ring size is discussed, and the G3 enthalpy of formation of tetrahydro-2H-1,3-thiazine-2-thione (72.4 kJ*mol 1) was also computed for this purpose.
Compounds
#
Formula
Name
1
H2O4S
sulfuric acid
2
CO2
carbon dioxide
3
N2
nitrogen
4
H2O
water
5
O2
oxygen
6
C4H7NOS
tetrahydro-2H-1,3-oxazine-2-thione
Datasets
The table above is generated from the ThermoML associated json file (link above).
POMD and RXND refer to PureOrMixture and Reaction Datasets. The compound numbers are included in properties, variables, and phases, if specificied;
the numbers refer to the table of compounds on the left.
Type
Compound-#
Property
Variable
Constraint
Phase
Method
#Points
POMD
6
Normal melting temperature, K ; Crystal
Crystal
Liquid
Air at 1 atmosphere
VISOBS
1
POMD
6
Mass density, kg/m3 ; Crystal
Temperature, K; Crystal
Pressure, kPa; Crystal
Crystal
Buoyancy - hydrostatic balance
1
POMD
6
Vapor or sublimation pressure, kPa ; Crystal
Temperature, K; Crystal
Crystal
Gas
KNUDSEN:UFactor:3
21
RXND
1
6
2
3
4
5
Specific internal energy of reaction at constant volume, J/g