Qiong He, M. Zheng, A. Farajtabar
Jul 1, 2018
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Influential Citations
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Journal
Journal of Solution Chemistry
Abstract
The solubility of 3-methyl-2-nitrobenzoic acid in nine organic solvents: methanol, ethanol, n-propanol, isopropanol, ethyl acetate, acetone, acetonitrile, 1,4-dioxane and N-methyl-2-pyrrolidone (NMP) was determined using the isothermal saturation method over a temperature range from 283.15 to 318.15 K under atmospheric pressure (101.2 kPa). Within the temperature range studied, the mole fraction solubility of 3-methyl-2-nitrobenzoic acid in the solvents increased with a rise of temperature. The solubilities obey the following order from high to low in different solvents: 1,4-dioxane > acetone > NMP > methanol > ethanol > (ethyl acetate, isopropanol) > n-propanol > acetonitrile. The solubility data of 3-methyl-2-nitrobenzoic acid in the studied solvents was correlated by using the λh equation, Wilson model and NRTL model. The maximum values of root–mean–square deviation and relative average deviation are 1.60 × 10−4 and 0.57%, respectively. In general, the selected models are all acceptable for describing the solubility of 3-methyl-2-nitrobenzoic acid in these solvents. In addition, the solvent effect was studied by using the Kamlet–Taft linear solvation energy relationship. The type and extent and direction of solute–solvent interactions were identified. Furthermore, the dissolution Gibbs energy, dissolution enthalpy, dissolution entropy, activity coefficient at infinitesimal concentration $$ (\gamma_{1}^{\infty } ) $$(γ1∞) and molar excess enthalpy $$ (H_{1}^{{{\text{E}},\infty }} ) $$(H1E,∞) were evaluated. The solubility data and thermodynamic studies will be very helpful for optimizing the purification process of 3-methyl-2-nitrobenzoic acid from its isomer mixtures.