The second part of this compendium concludes with a collection of phase change enthalpies of organic molecules inclusive of C11–C192 reported over the period 1880–2015. Also included are phase change enthalpies including fusion, vaporization, and sublimation enthalpies for organometallic, ionic liquids, and a few inorganic compounds. Paper I of this compendium, published separately, includes organic compounds from C1 to C10 and describes a group additivity method for evaluating solid, liquid, and gas phase heat capacities as well as temperature adjustments of phase changes. Paper II of this compendium also includes an updated version of a group additivity method for evaluating total phase change entropies which together with the fusion temperature can be useful in estimating total phase change enthalpies. Other uses include application in identifying potential substances that either form liquid or plastic crystals or exhibit additional phase changes such as undetected solid–solid transitions or behave ani...

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Phase Transition Enthalpy Measurements of Organic and Organometallic Compounds and Ionic Liquids. Sublimation, Vaporization, and Fusion Enthalpies from 1880 to 2015. Part 2. C11–C192

Although many organic molecules commonly found in the atmosphere are known to be surface-active in macroscopic aqueous solutions, the impact of surface partitioning of organic molecules to a microscopic aqueous droplet interface remains unclear. Here we measure the droplet size formed, at a relative humidity (∼99.9%) just below saturation, on submicrometer particles containing an ammonium sulfate core and an organic layer of a model compound of varying thickness. The 12 model organic compounds are a series of dicarboxylic acids (C3 to C10), cis-pinonic, oleic, lauric, and myristic acids, which represent a broad range in solubility from miscible (malonic acid) to insoluble. The variation in droplet size with increasing organic aerosol fraction cannot be explained by assuming the organic material is dissolved in the bulk droplet. Instead, the wet droplet diameters exhibit a complex and nonlinear dependence on organic aerosol volume fraction, leading to hygroscopic growth that is in some cases smaller and in others larger than that predicted by bulk solubility alone. For palmitic and stearic acid, small droplets at or below the detection limit of the instrument are observed, indicating significant kinetic limitations for water uptake, which are consistent with mass accommodation coefficients on the order of 10(-4). A model based on the two-dimensional van der Waals equation of state is used to explain the complex droplet growth with organic aerosol fraction and dry diameter. The model suggests that mono- and dicarboxylic acids with limited water solubility partition to the droplet surface and reduce surface tension only after a two-dimensional condensed monolayer is formed. Two relatively soluble compounds, malonic and glutaric acid, also appear to form surface phases, which increase hygroscopicity. There is a clear alternation in the threshold for droplet growth observed for odd and even carbon number diacids, which is explained in the model by differences in the excluded molecular areas of even (∼40 A(2)/molecule) and odd (∼20 A(2)/molecule) diacids. These differences are consistent with the odd diacids arranged at the droplet interface in "end-to-end" configurations with only one acid group in contact with the aqueous phase, which is in contrast to even carbon numbered diacids forming "folded" films with both acid groups in contact with the bulk phase. Organic matter produced by the ozonolysis of α-pinene forms surface films that exhibit similar behavior and become thinner with oxidation, allowing for greater water uptake. These results reveal a new and complex relationship between the composition of an organic aerosol and its hygroscopicity, suggesting that organic surface films might strongly influence cloud droplet formation as well as the multiphase chemistry of organic aerosols.

Surface organic monolayers control the hygroscopic growth of submicrometer particles at high relative humidity.

The solubility of isatin in eight pure solvents including dichloromethane, toluene, acetone, ethyl acetate, 1,4-dioxane, N,N-dimethylformamide, tetrahydrofuran, and acetonitrile were determined from (278.15 to 333.15) K at atmospheric pressure using the synthetic method. The solubility was determined by a laser monitoring observation technique and found to increase with the rise of temperature. The experimental solubilities were correlated by four models including the ideal solution model, the modified Apelblat equation, λh (Buchowski) equation, and Wilson models with the overall average percentage deviations less than 0.52% in all cases. Thermodynamic functions of the solution of isatin in these solvents including apparent standard enthalpy and entropy of solution were obtained by van’t Hoff plot, and the apparent standard Gibbs energy change of solution was also calculated.

Solubility and Thermodynamic Functions of Isatin in Pure Solvents

Measurement and correlation of solubility of ciclesonide in seven pure organic solvents

Measurement and correlation of solubility of thiourea in two solvent mixtures from T = (283.15 to 313.15) K

Measurement and correlation of solubility of dodecanedioic acid in different pure solvents from T = (288.15 to 323.15) K

An odd–even effect on solubility of dicarboxylic acids in organic solvents

The solubilities of the homologous series of dicarboxylic acids, HOOC–(CH2)n−2–COOH (n = 2–10), in water have been measured at temperatures ranging from 288.15 to 323.15 K by a static analytic method at atmospheric pressure. Dicarboxylic acids with even numbers of carbon atoms exhibit lower solubilities than acids with adjacent odd carbon numbers. The odd–even effect of solubility is most likely associated with the twist of the molecules, which influences the molecular packing in the solid state: the molecules stack with some offset in the cases of even (n = even) series, but without offset in the cases of odd (n = odd) series, whereas the carboxyl groups are twisted in even members. The interlayer packing is looser in odd members than that in even ones. The energies of intramolecular torsion were calculated using Materials studio 6.0 (Accelrys Software Inc.). Finally, the molar Gibbs energies were predicted, which also showed odd–even alternation.

Identification and Molecular Understanding of the Odd–Even Effect of Dicarboxylic Acids Aqueous Solubility

Measurement and correlation of the solubility of 4,4'-oxydianiline in different organic solvents

In this work, the solubility of IMP in a water + ethanol system was measured by a gravimetric method at the temperature range from 283.15 to 323.15 K. To explain the solubility behavior of IMP in t...

Zengkun Liu

Papers

Measurement and correlation of solubility of dodecanedioic acid in different pure solvents from T = (288.15 to 323.15) K

An odd–even effect on solubility of dicarboxylic acids in organic solvents

Identification and Molecular Understanding of the Odd–Even Effect of Dicarboxylic Acids Aqueous Solubility

Measurement and correlation of the solubility of 4,4'-oxydianiline in different organic solvents

Investigation of the Crystallization of Disodium 5′-Inosinate in a Water + Ethanol System: Solubility, Nucleation Mechanism, and Crystal Morphology