EXCESS MOLAR ENTHALPIES OF AN ALKANOL PLUS A BRANCHED-CHAIN ETHER AT THE TEMPERATURE 298.15 K

Excess molar enthalpies H-m(E) measured at 298.15 K in a flow calorime ter are reported for 12 mixtures of methanol or ethanol or propan-1-ol or propan-2-ol + bis(1-methylethyl) ether (IPE) or 1,1-dimethylethyl methyl ether (TBME) or 1,1-dimethylpropyl methyl ether (TAME). For all of the systems investigated, except the methanol mixtures, H-m(E) is positive over the whole mole fraction range and increases in the order methanol < ethanol < propan-1-ol < propan-2-ol. Small exothermic H-m( E) values are obtained for methanol + bis(1-methylethyl) ether or 1,1- dimethylethyl methyl ether or 1,1-dimethylpropyl methyl ether at high methanol mole fractions. The results are explained in terms of the str ong self-association of the alkanol and the cross-association of the e ther oxygen and the hydroxyl alcohol group.