Study on the Solubilities of Mononitro-Substituted Products of Nitration of m-Toluic Acid in Several Solvents at Temperatures between 297.65 and 351.75 K

Abstract

Mononitro-substituted products derived from the nitration of m-toluic acid are 3-methyl-4-nitrobenzoic acid, 3-methyl-2-nitrobenzoic acid, and 5-methyl-2-nitrobenzoic acid, which are all crucial intermediates of pesticides and medicines. The solubilities of 3-methyl-4-nitrobenzoic acid, 3-methyl-2-nitrobenzoic acid, and 5-methyl-2-nitrobenzoic acid in water, methanol, ethanol, n-propanol, formic acid, acetic acid, and propanoic acid were measured at different temperatures (297.65−351.75 K) and under atmospheric pressure. As expected, the same solute has different solubilities in different solvents, and the dissolved amounts of these three solutes are also diverse in the same solvent. Subsequently the experimental solubility data of three mononitro-substituted products of m-toluic acid nitration in several solvents were correlated with the modified Apelblat equation and the NRTL activity coefficient model, and the calculated values are in excellent agreement with known experimental data in the temperature range studied.

Measurement and Correlation of Solubilities of 3-Methyl-2-Nitrobenzoic Acid, 3-Methyl-4-Nitrobenzoic Acid, and 5-Methyl-2-Nitrobenzoic Acid in n-Butanol Isomer Solvents

“…To check the accuracy and reliability of the experimental method used in this study, the solubility data of 3-M-4-NBA in methanol and ethanol have been compared with those in the literature. 6,7 The data compared in Figures 1 and 2show that the measurement of the solubility of 3-M-4-NBA in methanol and ethanol is consistent with the trend of the literature data. The average relative deviation (ARD) of literature data and experimental data in methanol and ethanol is 4.57 and 6.13%, indicating the accuracy of our experimental technology and reliability of measured solubility data(Tables 2 and 3).…”

“…c RD is the relative deviation between the experimental solubility data and literature data. 6,7 ARD is the average relative deviation. c RD = (x-x b )/x b .…”

“…Solubility x 1 of 3-M-4-NBA in methanol: solid box measured in this work, open up-pointing triangle, literature data from Wu, and open circle, literature data from He …”

“…4,5 Of course, there are many reports on these three acids about the solid−liquid equilibrium (SLE). 6−9 He et al determined the solubility of 3-M-2-NBA, 3-M-4-NBA, and 5-M-2-NBA in methanol, ethanol, n-propanol, formic acid, acetic acid, propanoic acid, and water; 6 Wu measured the solubility of 3-M-4-NBA in water, methanol, ethanol, n-propanol, n-butanol, and other solvents. 7 Unfortunately, no one has systematically studied the changes of thermodynamic properties of these three isomeric aromatic acids in isomeric solvents, so the solubility of 3-M-2-NBA, 3-M-4-NBA, and 5-M-2-NBA in n-butanol, isobutanol, tert-butanol, and sec-butanol would be studied at atmospheric pressure.…”

“…3-Methyl-2-nitrobenzoic acid (3-M-2-NBA), 3-methyl-4-nitrobenzoic acid (3-M-4-NBA), and 5-methyl-2-nitrobenzoic acid (5-M-2-NBA) are important intermediates of chemical organic compounds, which are widely used in pesticide, medicine, and other fields. − These three acids are isomers of aromatic carboxylic acids. Although these aromatic carboxylic acid isomers have the same functional group composition, literature studies have reported their different thermodynamic properties. , Of course, there are many reports on these three acids about the solid–liquid equilibrium (SLE). − He et al determined the solubility of 3-M-2-NBA, 3-M-4-NBA, and 5-M-2-NBA in methanol, ethanol, n -propanol, formic acid, acetic acid, propanoic acid, and water; Wu measured the solubility of 3-M-4-NBA in water, methanol, ethanol, n -propanol, n -butanol, and other solvents . Unfortunately, no one has systematically studied the changes of thermodynamic properties of these three isomeric aromatic acids in isomeric solvents, so the solubility of 3-M-2-NBA, 3-M-4-NBA, and 5-M-2-NBA in n -butanol, iso-butanol, tert-butanol, and sec-butanol would be studied at atmospheric pressure.…”