Vapor Pressures and Phase Diagrams of Two Methyl Esters of Substituted Benzoic Acids

• Type: Article in International Scientific Journal
• Date: 2011

Authors

Ana R R P Almeida (Author) Other; Manuel J S Monte (Author) FCUP

Journal

Title: Journal of Chemical & Engineering Data

Vol. 56

Pages: 4862-4867

ISSN: 0021-9568

Publisher: American Chemical Society

Indexing

ISI Web of Knowledge - 21 Citations

Scopus - 21 Citations

Scientific classification

FOS: Engineering and technology > Chemical engineering

Other information

Authenticus ID: P-002-J86

DOI: 10.1021/je2007605

Abstract (EN): The vapor pressures of condensed phases of methyl p-methylbenzoate and methyl p-(dimethylamino)benzoate were measured in the temperature ranges (269.3 to 357.0) K and (325.0 to 390.4) K, respectively, using a static method. The Knudsen mass-loss effusion technique was also used to study the vapor pressures as function of temperature of the crystals of methyl p-(dimethylamino)benzoate in the pressure range (0.1 to 1) Pa. The results obtained for each compound enabled the determination of the standard molar entropies and enthalpies of sublimation and of vaporization at T = 298.15 K as well as phase diagram representations of the (p,T) experimental data. The temperatures and molar enthalpies of fusion were determined using differential scanning calorimetry and were compared with the values derived from the vapor pressure measurements. The enthalpies of the intermolecular hydrogen bonds O-H center dot center dot center dot O in the crystalline phase of the parent substituted benzoic acids were calculated.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 6