Vapor Pressure, Vaporization Enthalpies, Critical Parameters, and Heat Capacities of Alkyl Glycolates

Abstract

Developing biotechnological methods to produce glycolic acid and alkyl glycolates requires knowledge of thermophysical and thermodynamic data. Vapor pressures of linear alkyl glycolates HO–CH2–COO–(CH2) n –H with n = 1–8 were determined by the transpiration method. Standard molar enthalpies of vaporization at experimental temperature and at 298.15 K were derived from the temperature dependence of the vapor pressure. The critical temperatures and pressures of alkyl glycolates were measured by the pulse-heating method. The experimental data were successfully checked for internal consistency. Molar heat capacity of atmospheric pressure for liquid esters was measured by the method of differential scanning calorimetry in the temperature range 303–423 K. The molar liquid heat capacities at 298.15 K and atmospheric pressure of alkyl glycolates were calculated from the result of this work. The measured values were used for estimating prediction capabilities of group-contribution methods by Constantinou and Gani, Marrero and Gani, and Hukkerikar et al. for critical properties and Chickos and Acree, Domalski and Hearing, and Ceriani et al. for heat capacity at 298.15 K. Results of this study could be used for the design and optimization of the chemical processes of the utilization of renewable feedstock.

Density and Viscosity of Glycolic, Lactic, and Malic Acid Esters

“…Liquid esters were purified using fractional distillation at reduced pressure (10 to 15 Torr) and dried over Na 2 SO 3 . Methods of synthesis and isolation are described in detail in previous works. − …”

Calculation of the Vapour Pressure of Organic Molecules by Means of a Group-Additivity Method and their Resultant Gibbs Free Energy and Entropy of Vaporization at 298.15K

“…Further collective sources have been used to complement -and compare -the experimental data [8,14,[23][24][25][26][27][28][29][30][31]. In addition, vapour-pressure data have been published specifically for various saturated and unsaturated hydrocarbons , alcohols [54][55][56][57][58][59], phenols [60,61], alkyl-and arylethers [62][63][64][65], acetals [66,67], carboxylic acids [68][69][70][71][72], carboxylic halides [73], carboxylic esters and lactones [74][75][76][77][78][79][80][81][82][83][84][85][86][87], carbonates [88][89][90]…”

New Method of NPOH Equation-Based to Estimate the Physicochemical Properties of Noncyclic Alkanes

“…Due to the huge number of isomers of alkanes, determining the physicochemical properties of all compounds experimentally is an impossible task, so it is very meaningful to establish an estimation method. Until now, people have gradually established many valuable estimation methods, − such as (i) group-contribution (GC) methods, ,,,,,,, (ii) estimating one physicochemical property from that of other compounds, <...…”

“…Due to the huge number of isomers of alkanes, determining the physicochemical properties of all compounds experimentally is an impossible task, so it is very meaningful to establish an estimation method. Until now, people have gradually established many valuable estimation methods, 1 − 95 such as (i) group-contribution (GC) methods, 4 , 9 , 18 , 37 , 54 , 55 , 70 , 86 (ii) estimating one physicochemical property from that of other compounds, 1 , 2 , 8 , 14 , 16 , 17 , 19 , 20 , 22 , 24 , 36 , 39 , 45 , 48 , 57 , 64 − 66 , 74 , 75 , 78 , 85 , 89 (iii) liquid equations of states (EoS)-based methods, 3 , 5 , 7 , 11 , 13 , 21 , 25 , 26 , 31 , 34 , 40 , 41 , 46 , 47 , 49 − 51 , 53 , 61 , 88 , 90 − 92 and (iv) quantitative structure–property relationships (QSPRs). 15 , 30 , 38 , 42 , 44 , 52 , 56 , 59 , 60 ...…”