Thermochimica Actu, 232 (1994) 317- 321 ElseGier Science B.V., Amsterdam SsL)I ~-6~31(93)0134~-5 Note 317 Vaporization enthalpies of five odd-numbered (C, to C15) (Y, u “alkauediols Vincenzo Piacente a,*, Daniela Ferro b and Giuseppe Della Gatta ’ ’ ~ipart~rne~ro di Chim~ca, ~n~uer.~~t~ “La Sapienza”, Piazzale A. ~oro 5, 0018.5 Rome tffaly ) ’ C.N.R., Cenrrn per Ea Termod~nam~ca C~~rn~ca aile A&e Temperature, c/o ~~par~~ment~ di Chimica, UniversitS “La Sapienza”, Rome (Italy) ’ ~ipar~~mento di Chimica Inorganica, Chimica Fisica e Chimica dei Materiali, Universitci di Torino, Via P. Ciuria 9, 10125 Turin (Italy) (Received 27 April 1993; accepted 18 July 1993) Abstract The temperature dependence of vapour pressures for liquid C, to C,, odd-numbered terminal dids was measured by the torsion-effusion method. Corresponding vaporization enthalpies were derived. Our continuing study of the vaporization thermodynamics of pure organic compounds {l] has inciuded investigation on the C, to C,, homologous series of even-numbered cy, w -alkanediols [2]. This paper extends our work to the five odd-numbered (C, to C,,) members of this series. Knauth and Sabbah [3] used a Tian-Caivet calorimeter, fitted with a Knudsen effusion cell, to measure at 323 K the vaporization enthalpies of 1,7-heptanediol and 1,9-uonanedio~ and a single value of their vapour pressure at the same temperature. Apart from some temperature-vapour pressure equations obtained in the high-pressure ranges and the standard vaporization enthalpies of lower diols (up to C,) 14-71, there are apparently no other data on the odd~numbered diols in the literature. In the present work, the temperature dependence of the vapour pressures for the C, to C,, diols were measured by the torsion-elusion method, and the corresponding vaporization enthalpies were derived. Three diols (1,9-nonanediol (Janssen, 99%), l,ll-undecanediol (Pfaltz and Bauer) and 1,15-pentadecanediol (K & K Labs.)) were high-purity commercial products further puri~ed by successive crystallizations from * Corresponding author. 0~40-~~3~/94/$~7.~ 0 1994 - Elsevier Science B.V. All rights reserved