ABSTRACT

Molar enthalpies of dissolution, DslnHm, of decyl-, dodecyl-, tetradecyl- and hexadecyl-trimethylammonium bromide salts (RMe3NBr) in water have been measured calorimetrically as a function of concentration and temperature. Standard state values, DslnHo m, were obtained by extrapolation to infinite dilution and showed a smooth variation with the number of carbon atoms, nC, in the alkyl chain R, unlike their shorter congeners (nC 6 6). The corresponding molar isobaric heat capacity changes, DslnCo p;m, were calculated from the temperature dependence of DslnHo m and also varied smoothly with nC but were more than an order of magnitude greater than those of their shorter congeners, probably reflecting a marked increase in hydrophobicity with increasing nC. The behaviour of the RMe3NBr salts was found to parallel broadly that of the symmetrical tetraalkylammonium salts, R4NBr.

Compounds

#	Formula	Name
1	C13H30BrN	N,N,N-trimethyl-1-decanaminium bromide
2	C15H34BrN	dodecyltrimethylammonium bromide
3	C17H38BrN	tetradecyltrimethylammonium bromide
4	C19H42BrN	N,N,N-trimethyl-1-hexadecanaminium bromide
5	H2O	water

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	1 5	Molar enthalpy of solution, kJ/mol ; Liquid	Temperature, K; Liquid Molality, mol/kg - 1; Liquid	Pressure, kPa; Liquid	Liquid	ISOPERIBOL	39
POMD	2 5	Molar enthalpy of solution, kJ/mol ; Liquid	Temperature, K; Liquid Molality, mol/kg - 2; Liquid	Pressure, kPa; Liquid	Liquid	ISOPERIBOL	41
POMD	3 5	Molar enthalpy of solution, kJ/mol ; Liquid	Temperature, K; Liquid Molality, mol/kg - 3; Liquid	Pressure, kPa; Liquid	Liquid	ISOPERIBOL	42
POMD	4 5	Molar enthalpy of solution, kJ/mol ; Liquid	Temperature, K; Liquid Molality, mol/kg - 4; Liquid	Pressure, kPa; Liquid	Liquid	ISOPERIBOL	38

Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

Enthalpies of dissolution of long chain-length alkyltrimethylammonium bromide salts in water at temperatures from 278.15 to 308.15 K

Riveros, D. C.[Diana C.], Vargas, E. F.[Edgar F.], Hefter, G.[Glenn]

ABSTRACT