Osmotic coefficients of alkyltrimethylammonium bromides in water and in aqueous sodium bromide solutions at 55.degree.C

Abstract

We have measured osmotic coefficients of aqueous solutions of decyltrimethylammonium bromide, dodecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, and hexadecyltrimethylammonium bromide at 55 °C and at concentrations ranging from 0.01 to 0.30 m. The measurements were made with a vapor pressure osmometer/molecular weight apparatus. We have also measured the osmotic coefficients of aqueous mixtures of sodium bromide and these same surfactants. The ratio of molalities of surfactant to added salt was held constant at 1:1. A mass-action model that includes activity coefficients of all species in solution was used to analyze the data.

Osmotic coefficients and enthalpies of dilution of aqueous sodiumn-alkane-1-sulphonates at the temperatures (298.15, 313.15, 328.15, and 343.15) K

“…The stoichiometric osmotic coefficient for a given solution was estimated from the measured output from the vapour pressure osmometer: (9,14) f = kDR/2m, where DR is the difference between two readings. The first reading is the differential resistance measured when both thermistors hold reference solvent, in this case water.…”

“…The vapour-pressure osmometry measurements were made with a Hitachi Perkin-Elmer Model 115 molar mass apparatus maintained at T = (328.15 2 0.1) K. This type of osmometer, its principles of operation, and its application to the estimation of osmotic coefficients of surfactant solutions have been described previously. (8)(9)(10)(11)(12)(13)(14) Details of the experimental procedure, the calculation of osmotic coefficients, and the method of calibration were identical to those described in an earlier study. (14) The calibration constant was determined by making a series of measurements of NaCl(aq) solutions.…”

“…(8)(9)(10)(11)(12)(13)(14) Details of the experimental procedure, the calculation of osmotic coefficients, and the method of calibration were identical to those described in an earlier study. (14) The calibration constant was determined by making a series of measurements of NaCl(aq) solutions. The osmotic coefficients for NaCl(aq) were calculated from the Bro¨nsted-Guggenheim ion-interaction parameter and its temperature coefficient taken from the literature.…”

“…The total uncertainty in the average values of the reported osmotic coefficients f for the surfactant solutions was estimated to range from 10 −2 ·f to 3·10 −2 ·f, based, in part, on these calibration measurements. (14) Enthalpies of dilution were measured with a Tronac Model 450 isoperibol titration calorimeter with a Tronac Model 1040 temperature controller. Details of the modified burette injection system, experimental procedure, method of calibration, and data collection system have been described previously.…”

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

“…Not surprisingly therefore, the thermodynamic and transport properties of the RMe 3 NX salts in water have been studied extensively. Measurements have included molar volumes [1][2][3][4][5][6][7], electrical conductivities [4,5,[7][8][9], heat capacities [3,4,7,10], osmotic coefficients [7,11] and dilution enthalpies [12,13]. Studies relating to the micellar behaviour of RMe 3 NX salts in water and other solvents have also been reported [14,15].…”