Investigation into Solubility and Solvent Effect of 2-Aminopyridine in Different Mono-Solvents Over Temperatures from 273.15 to 313.15 K

The solubility data of 2-aminopyridine in 13 neat solvents were determined using the shake-flask method, including methanol, N,N-dimethylformamide (DMF), n-propanol, isopropanol, ethanol, n-butanol, N-methyl-2-pyrrolidine (NMP), isobutanol, n-hexane, cyclohexane, acetonitrile, amyl acetate, and n-propyl acetate. The mole fractions of 2-aminopyridine in equilibrium liquid phase rose with the increase in temperature and followed the decreasing order in different solvents: NMP > DMF > methanol > ethanol > n-propanol > n-butanol > n-propyl acetate > amyl acetate > isopropanol > isobutanol > acetonitrile > n-hexane > cyclohexane. The lambda h equation, NRTL model, modified Apelblat equation, and Wilson model were used to fit them. The greatest root-mean-square deviation value and relative average deviation value obtained were 160.4 x 10(-4) and 4.46 x 10(-2), respectively. For a given solvent, the modified Apelblat equation produced lower relative average deviation values than the other equations. The mixing characteristics, infinitesimal concentration activity coefficient, and reduced excess enthalpy were also calculated. Furthermore, the degree and type of interactions of solute-solvent and solvent-solvent were identified utilizing the relationship analysis of Kamlet and Taft linear solvation energy of solvent effect.

Automated summary

The solubility of 2-aminopyridine in 13 neat solvents was determined and fitted using several models. The mixing characteristics and excess enthalpy were calculated, and the interactions between solute-solvent and solvent-solvent were analyzed.