The distribution of trialkylphosphates between dodecane and water

Abstract

). The distribution of the four lower trialkylphosphates, triethyl, trimethyl, tripropyl, and tributylphosphates, between dodecane and water has been measured a s a function of temperature between 293.15 K and 3 13.15 K , and as a function of trialkylphosphate concentration at concentrations below 0.1 mol/dm3. From these results, the thermodynamic functions associated with the transfer of each of these trialkylphosphates from water to dodecane were calculated. With the exception of trimethylphosphate, free energies of transfer changed by -3.5 kJ/mol for each methylene group added to the solute. The enthalpies of transfer for all the trialkylphosphates were in the range of 26 to 30 kJ/mol, so that most of the differences in the free energies of transfer arise from entropic differences.Dimerization constants for the trialkylphosphates in dodecane were consistent with those available in the literature. Chem. 58,1463Chem. 58, (1980. On a mesure la distribution des 4 trialkylphosphates inferieurs, tritthyl-, trimethyl-, tripropyl-et tributylphosphates, entre le dodecane et I'eau, en fonction de la temperature entre 293.15 et 3 13.15 K et en fonction de laconcentration de trialkylphosphate pour des concentrations inferieurs a 0.1 mol/dm3. A partir de ces resultats, on a calcule les fonctions thermodynamiques associees au transfert de chacun de ces trialkylphosphates de I'eau au docecane. A I'exception du cas du trimethylphosphate, I'addition d'un groupe methylenique au solutt provoque une variation de -3.5 kJ1mol dans I'tnergie libre de transfert. Les enthalpies de transfert de tous les trialkylphosphates sont de I'ordre de 26 i 30 kJ1mol de telle sorte que la plupart des differences des energies libres de transfert proviennent de differences entropiques.Les constantes de dimtrisation des trialkylphosphates dans le dodecane sont en accord avec celles rapportees dans la litterature.[Traduit par le journal] IntroductionTBP have been measured in hexane and dodecane Tributylphosphate has been widely used in ex-(7) and enthalpies of Solution of TPP are available traction processes for separating the components for water (61, and i-octane (8)-The distribution of irradiated nuclear fuel (1). As part of a program TEP and TMP between water and to study the interfacial properties relevant to such dodecane have not been measured-For both solsolvent extraction systems, we have studied the utes good calorimetric data on enthalpies of soluof trimethylphosphate (TMP), triethyl-tion in Water (5) are available but little is known phosphate (TEP), t r i p r o p y~p~o s p~a t e (~p p ) , and about their enthalpies of solution in alkanes. The tributylphosphate (TBP) (2) at the dodecane-water only data available are for TEPin i-octane (8)-interface. In order to interpret these adsorption It therefore seemed appropriate to make a cornresults, it is necessary to have a good ther-plete study of the distribution ratios of the four rnodynamic description of the process in which lower trialkylphosphates at Solute concentrations solute is trans...

Salting-out of triethylphosphate by inorganic electrolytes

“…We are studying interfacial properties relevant to these extraction systems (2,3), and need to know distribution coefficients for organic phosphates between hydrocarbons and various aqueous media (4), including aqueous media with added salt. Measuring such distribution coefficients is equivalent to measuring the salting coefficients (5).…”

“…by gas chromatography, as previously described (4). Since most of the TEP goes into the water phase (4), it was possible to determine distribution coefficients by analyzing the organic phase before and after equilibration, and using a mass balance.…”

“…The sources and purification of dodecane, water, and TEP have been described (2,4). The inorganic salts were of ACS reagent-grade purity, or better, and were used without further purification.…”

The distribution of branched octanols between dodecane and water

“…Such standard states have the advantage that the reference states are temperature independent. Since both KD and K.; refer to infinite dilution, their ratio is simply given by the ratio of the molar volumes of the two solvents (10,14).…”

“…Thc general procedurcs have bcen dcscribcd prcviously ( 10). Analyscs of alcohol concentrations werc done.…”