ABSTRACT

The enthalpies of solution, solvation and vaporization/sublimation are interrelated values combined in the simplest thermodynamic circle. Hence, experimental determination of vaporization/sublimation enthalpy can be substituted by experimentally simpler determination of solution enthalpy when solvation enthalpy is known. Previously it was found that solvation enthalpies of a wide range of unbranched aliphatic and aromatic solutes in saturated hydrocarbons are in good linear correlation with their molar refraction values. This allows to estimate the vaporization/sublimation enthalpy of any unbranched organic compound from its solution enthalpy in saturated hydrocarbon and molar refraction. In the present work this approach was modified for determination of vaporization/sublimation enthalpy of branched-chain alkyl aromatic and aliphatic compounds. Group contributions to the enthalpy of solvation due to the branching of carbon chain were evaluated. Enthalpies of solution at infinite dilution of 18 branched-chain aliphatic and alkyl aromatic compounds were measured at T = 298.15 K. Vaporization/sublimation enthalpies for 35 branched aliphatic and alkyl aromatic compounds were determined by using modified solution calorimetry approach. These values are in good agreement with available literature data on vaporization/sublimation enthalpies obtained by conventional methods.

Compounds

#	Formula	Name
1	C10H14	(1-methylpropyl)benzene
2	C8H10	1,2-dimethylbenzene
3	C8H10	1,3-dimethylbenzene
4	C9H12	1,3,5-trimethylbenzene
5	C9H12	1,2,4-trimethylbenzene
6	C10H14	1,2,4,5-tetramethylbenzene
7	C12H18	hexamethylbenzene
8	C12H16	cyclohexylbenzene
9	C11H10	1-methylnaphthalene
10	C12H12	1,6-dimethylnaphthalene
11	C13H12	4-methylbiphenyl
12	C16H18	3-(1,1-dimethylethyl)-1,1'-biphenyl
13	C14H14	1,2-diphenylethane
14	C19H16	triphenylmethane
15	C25H20	1,1',1'',1'''-methanetetrayltetrakisbenzene
16	C12H10	acenaphthene
17	C13H10	fluorene
18	C5H10O2	methyl 2-methylpropanoate
19	C6H12O2	methyl 2,2-dimethylpropanoate
20	C6H12	cyclohexane

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	Phase	Method	#Points
POMD	20 1	Molar enthalpy of solution, kJ/mol ; Liquid	Mole fraction - 1; Liquid Pressure, kPa; Liquid Temperature, K; Liquid	Liquid	Titration calorimetry	1
POMD	2 20	Molar enthalpy of solution, kJ/mol ; Liquid	Mole fraction - 2; Liquid Pressure, kPa; Liquid Temperature, K; Liquid	Liquid	Titration calorimetry	1
POMD	3 20	Molar enthalpy of solution, kJ/mol ; Liquid	Mole fraction - 3; Liquid Pressure, kPa; Liquid Temperature, K; Liquid	Liquid	Titration calorimetry	1
POMD	4 20	Molar enthalpy of solution, kJ/mol ; Liquid	Mole fraction - 4; Liquid Pressure, kPa; Liquid Temperature, K; Liquid	Liquid	Titration calorimetry	1
POMD	5 20	Molar enthalpy of solution, kJ/mol ; Liquid	Mole fraction - 5; Liquid Pressure, kPa; Liquid Temperature, K; Liquid	Liquid	Titration calorimetry	1
POMD	6 20	Molar enthalpy of solution, kJ/mol ; Liquid	Mole fraction - 6; Liquid Pressure, kPa; Liquid Temperature, K; Liquid	Liquid	Power-compensation calorimetry	1
POMD	7 20	Molar enthalpy of solution, kJ/mol ; Liquid	Mole fraction - 7; Liquid Pressure, kPa; Liquid Temperature, K; Liquid	Liquid	Power-compensation calorimetry	1
POMD	20 8	Molar enthalpy of solution, kJ/mol ; Liquid	Mole fraction - 8; Liquid Pressure, kPa; Liquid Temperature, K; Liquid	Liquid	Titration calorimetry	1
POMD	9 20	Molar enthalpy of solution, kJ/mol ; Liquid	Mole fraction - 9; Liquid Temperature, K; Liquid Pressure, kPa; Liquid	Liquid	Titration calorimetry	1
POMD	20 10	Molar enthalpy of solution, kJ/mol ; Liquid	Mole fraction - 10; Liquid Temperature, K; Liquid Pressure, kPa; Liquid	Liquid	Titration calorimetry	1
POMD	20 11	Molar enthalpy of solution, kJ/mol ; Liquid	Mole fraction - 11; Liquid Temperature, K; Liquid Pressure, kPa; Liquid	Liquid	Power-compensation calorimetry	1
POMD	20 12	Molar enthalpy of solution, kJ/mol ; Liquid	Mole fraction - 12; Liquid Temperature, K; Liquid Pressure, kPa; Liquid	Liquid	Titration calorimetry	1
POMD	13 20	Molar enthalpy of solution, kJ/mol ; Liquid	Mole fraction - 13; Liquid Temperature, K; Liquid Pressure, kPa; Liquid	Liquid	Power-compensation calorimetry	1
POMD	20 14	Molar enthalpy of solution, kJ/mol ; Liquid	Mole fraction - 14; Liquid Temperature, K; Liquid Pressure, kPa; Liquid	Liquid	Power-compensation calorimetry	1
POMD	20 15	Molar enthalpy of solution, kJ/mol ; Liquid	Mole fraction - 15; Liquid Temperature, K; Liquid Pressure, kPa; Liquid	Liquid	Power-compensation calorimetry	1
POMD	16 20	Molar enthalpy of solution, kJ/mol ; Liquid	Mole fraction - 16; Liquid Temperature, K; Liquid Pressure, kPa; Liquid	Liquid	Power-compensation calorimetry	1
POMD	17 20	Molar enthalpy of solution, kJ/mol ; Liquid	Mole fraction - 17; Liquid Temperature, K; Liquid Pressure, kPa; Liquid	Liquid	Power-compensation calorimetry	1
POMD	20 18	Molar enthalpy of solution, kJ/mol ; Liquid	Mole fraction - 18; Liquid Temperature, K; Liquid Pressure, kPa; Liquid	Liquid	Titration calorimetry	1
POMD	20 19	Molar enthalpy of solution, kJ/mol ; Liquid	Mole fraction - 19; Liquid Temperature, K; Liquid Pressure, kPa; Liquid	Liquid	Titration calorimetry	1

Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

Modified solution calorimetry approach for determination of vaporization and sublimation enthalpies of branched-chain aliphatic and alkyl aromatic compounds at T = 298.15 K

Varfolomeev, M. A.[Mikhail A.], Novikov, V. B.[Vladimir B.], Nagrimanov, R. N.[Ruslan N.], Solomonov, B. N.[Boris N.]

ABSTRACT