DNP solubility measurement and automatic data processing in different pH water

In this study, DNP solubility data were examined using the gravimetric method under standard atmo-spheric pressure in the temperature range (288.15-323.15 K) with four types of water with pH of 5.62, 6.62, 7.50, 7.61 and four types of weak acidic water with pH of 2.14, 2.66, 3.02, 3.12. The result indi-cated that the solubility of DNP in the studied solvents increased with the increase of the temperature, and different pH resulted in different solubility growth trends at this temperature. (To be specific, the growth rate of solubility data was the fastest when pH was around 2.6, and the growth rate of solubility data was slower in water with pH of 6.6-7.5). The automatic calculation and saving of solubility data and the output of trend graph were achieved realized by developing Python code. With solubility models (in-cluding a,h equation, Jouyban-Acree model, NTRL model, Wilson model, the modified Apelblat equation) for data correlation fitting, the model correlation coefficient R2 all reached over 99.3 %, and the root mean square error (abbreviation RMSE), the error between the examined value and the obtained value was obtained. The enthalpy Delta mixH (KJ/mol), entropy Delta mixS (KJ center dot K-1.mol-1) and Gibbs free energy Delta mixG (KJ/mol) of the dissolution process were obtained, and the result indicated that Delta mixS > 0, Delta mixG < 0, thus indicating that the dissolution process of DNP is a spontaneous process and is entropy driven.(c) 2022 Published by Elsevier B.V.