Thermodynamic Study Of The Mixed System Of Trimethyl Phosphate With Alcohols, Water

The thermodynamic properties of trimethyl phosphate mixed with n-alkanols or water have been investigated in this paper.The excess molar enthalpies of binary mixtures for {Trimethyl Phosphate(TMP) + Methanol/Ethanol/Propan-1-ol/Butan-1-ol} were measured with a TAM Air Isothermal calorimeter at 298.15 K and atmospheric pressure.The experimental results have been correlated with the Redlish-Kister polynomial,and dissociated by the iterations of the Redlish-Kister polynomial.The H_m^E for {xTMP+(1-x)Alkanol} are positive in the whole range of composition,which indiate that the mixing process are endothermic.There is some regularity with the excess molar enthalpies in that the alkanol molecule increases with the number of carbon atom.When the x_(TMP)equals 0.30,the H_m^E value reaches maximum for {xTMP+(1-x)CH3OH},but for the other three systems,the maximum values appear when x_(TMP)=0.42,with a better symmetry.The H_m^E for {xTMP+(1-x)water} are negative in the whole range of composition,indiate that the mixing process are exothermic.IR spectra of the mixtures indicate the existence of hydrogen bonding between TMP and alkanols or water in the mixtures.The thermodynamic model for binary mixtures of {TMP+Methanol/Ethanol/Propan-1-ol/ Butan-1-ol/Water} provides the contributions of physical action and chemistry action.The excess molar enthalpies of ternary mixtures for {x₁TMP+x₂CH₃OH+ (1-x₁-x₂)H₂O} and {x₁TMP+x₂C₂H₅OH+(1-x₁-x₂)H₂O} were measured on the same conditions;The experimental results have been correlated with the experiential equation;Constant H_m.123^E contours at 298.15 K are plotted by using the method of least-squares.