Determination of the activity of a molecular solute in saturated solution

Nordström, Fredrik; Rasmuson, Åke C.

doi:10.1016/j.jct.2008.06.016

Cited by 49 publications

(65 citation statements)

References 12 publications

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“…If the heat capacity of the melt can be experimentally measured above and close to Tm, extrapolation down to the temperature of interest, e.g. by assuming a linear temperature dependence of ΔCp [8], can allow for the integration to be performed. However, heat capacity data is frequently unavailable, and often, ΔCp is either neglected completely or approximated with a constant value such as the entropy of fusion at Tm [9].…”

Section: Theorymentioning

confidence: 99%

“…However, heat capacity data is frequently unavailable, and often, ΔCp is either neglected completely or approximated with a constant value such as the entropy of fusion at Tm [9]. There is a growing awareness of the fact that the temperature dependence of ΔCp can be significant, and Nordström and Rasmuson [8] have described a method allowing ΔCp to be estimated using solubility data in multiple solvents.…”

Section: Theorymentioning

confidence: 99%

“…Accordingly, extrapolation of experimental solubility data to ln xeq = 0 can yield an estimate of the melting temperature, Tm, at which point the extrapolated van't Hoff enthalpy of solution provides an estimate of the enthalpy of fusion, ΔfusH (Tm). A commonly encountered misapprehension is that a van't Hoff plot should be linear, which would mean a constant Δsol vH H. However, it can be shown from basic thermodynamic relationships [8] that Δsol vH H may be written as:…”

Section: Theorymentioning

confidence: 99%

“…The natural starting point for model development should be the thermodynamically rigorous equation (2). The first term this equation, the activity of the solid as given by equation (3), satisfies all the boundary conditions given in equation (8). However, there is a scarcity of reported work dealing with the temperature dependence of the activity coefficient in solutions at equilibrium.…”

Section: Theorymentioning

confidence: 99%

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(Solid+liquid) solubility of organic compounds in organic solvents – Correlation and extrapolation

Svärd

Rasmuson

2014

The Journal of Chemical Thermodynamics

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A semi-empirical model is developed for the regression of solid-liquid solubility data with temperature. The model fulfils the required boundary conditions, allowing for robust extrapolation to higher and lower temperatures. The model combines a representation of the solid-state activity which accommodates a temperature-dependent heat capacity difference contribution with a scaled three-parameter Weibull function representing the temperature dependence of the solution activity coefficient at equilibrium. Evaluation of the model is based on previously published experimental calorimetric and solubility data of four organic compounds, fenoxycarb, fenofibrate, risperidone and butyl paraben, in five common organic solvents, methanol, ethyl acetate, acetone, acetonitrile, and toluene. The temperature dependence of the van't Hoff enthalpy of solution and its components is analysed and discussed. Among the four compounds the influence of temperature on the enthalpy of fusion varies from moderate to substantial. Based on the semi-empirical model, a new equation containing three adjustable parameters is proposed for regression and extrapolation of solubility data for cases when only melting data and solubility data is available. The equation is shown to provide good accuracy and robustness when evaluated against the full semiempirical model as well as against commonly used, more simple empirical equations. It is shown how such a model can be used to obtain an estimate of the heat capacity difference for cases where accurate solubility data is available in multiple solvents.2

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Section: Theorymentioning

confidence: 99%

Section: Theorymentioning

confidence: 99%

Section: Theorymentioning

confidence: 99%

Section: Theorymentioning

confidence: 99%

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(Solid+liquid) solubility of organic compounds in organic solvents – Correlation and extrapolation

Svärd

Rasmuson

2014

The Journal of Chemical Thermodynamics

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“…The thermodynamically stable polymorph at room temperature crystallizes in the monoclinic space group P21/c and will henceforth be termed form I, whereas form II crystallizes in the orthorhombic space group Pna21. Forms I and II are monotropically related with a ratio of solubilities, and solid state activities, of approximately 1.3 at ambient conditions 42,43 . The corresponding driving force for transformation from form II to form I is fairly constant between 10 and 50 °C, viz.…”

Section: Introductionmentioning

confidence: 99%

Influence of Solution Thermal and Structural History on the Nucleation of m-Hydroxybenzoic Acid Polymorphs

Nordström

Svärd

Malmberg

et al. 2012

Crystal Growth & Design

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The influence of solution pre-treatment on primary nucleation of m-hydroxybenzoic acid has been investigated through 550 cooling crystallization experiments. The metastable zone width has been determined at constant cooling rate and the time and temperature of the preceding superheating step have been varied. m-Hydroxybenzoic acid has two polymorphs and the influence of the polymorph used to prepare the solutions has also been investigated. There is an overall tendency in the experiments for the solution to exhibit a larger metastable zone width if it is superheated for a longer time and at a higher temperature, but under the investigated conditions this tendency is not very strong. The results show that the metastable form II preferentially crystallizes in all experiments and in particular when the solution has been more strongly superheated for several hours. However, when the time and/or the temperature of superheating is reduced there is an increasing tendency to obtain the stable form I. This is most clearly found for solutions prepared by dissolving form I. When the solutions are prepared by dissolution of form II, this tendency is weaker in what appears to be a systematic way. It is hypothesized that, unless the solution is strongly superheated for several hours, it will contain for a significant period of time clusters of solute molecules which can retain some degree of structure from the dissolved crystal. This leads to "memory" effects in the solution which may influence subsequent nucleation. The work includes a comprehensive review of previous published work on the influence of thermal history on nucleation in solutions and melts.

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Computing MOSCED parameters of nonelectrolyte solids with electronic structure methods in SMD and SM8 continuum solvents

et al. 2016

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An efficient method to predict modified separation of cohesive energy density model (MOSCED) parameters for nonelectrolyte solids using electronic structure calculations in SMD and SM8 continuum solvents is proposed and applied to acetanilide, acetaminophen, and phenacetin. The resulting parameters are ultimately used to predict the equilibrium solubility in a range of solvents over a range of temperatures. By combining MOSCED with SMD and SM8, we are able to leverage the strengths of both methods while eliminating shortcomings that would prevent their use alone for solvent selection in design processes involving nonelectrolyte solid solutes. Comparing to 77 non‐aqueous experimental solubilities of acetaminophen over the range 10–30°C, the proposed method has an average absolute error of 0.03 and 0.04 mol fracs for SMD and SM8 regressed parameters, respectively. Aqueous solubilities of acetaminophen over this temperature range are predicted with an average error of 0.030 and 0.0023 mol fracs, respectively. © 2016 American Institute of Chemical Engineers AIChE J, 63: 781–791, 2017

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Determination of the activity of a molecular solute in saturated solution

Cited by 49 publications

References 12 publications

(Solid+liquid) solubility of organic compounds in organic solvents – Correlation and extrapolation

(Solid+liquid) solubility of organic compounds in organic solvents – Correlation and extrapolation

Influence of Solution Thermal and Structural History on the Nucleation of m-Hydroxybenzoic Acid Polymorphs

Computing MOSCED parameters of nonelectrolyte solids with electronic structure methods in SMD and SM8 continuum solvents

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