The solid−liquid equilibrium data of vinpocetine in nine pure solvents and ethanol−water binary system at temperatures ranging from 283.15 to 323.15 K was experimentally measured by gravimetric method under atmospheric pressure. For the different types of investigated solvent, the solid−liquid equilibrium solubility of vinpocetine increased with augmented temperature. Experimental solubility was fitted with several thermodynamic models including the modified Apelblat model, λh model, and nonrandom two-liquid (NRTL) model, as well as the combined nearly ideal binary solvent/Redlich− Kister model. All the fitted values were in satisfactory agreement with the experimental results. The thermodynamic parameters were calculated by the activity coefficients of vinpocetine in different solvents, which were obtained by NRTL model. The results demonstrated that the mixing process of vinpocetine with experimental solvents was spontaneous and entropy-driven.

In this work, theophylline was selected as the model compound to study and simulate the solution-mediated polymorphic transformation. The polymorph I and polymorph II of theophylline were prepared and fully characterized. Raman and UV spectra methods were carried out to observe the phase transformation of theophylline from polymorph I to polymorph II at different temperatures. The theoretical models, including dissolution model, nucleation model, and growth model, were established to describe and simulate the transformation processes. By combination of experiments and simulations, the controlling steps of the transformation processes were discussed. The effects of temperature and/or solvent on the transformation processes were evaluated. This work can shed light on the polymorphic transformation processes.

In order to exploit Co–Cu synergistic effect to develop catalyst with high activity, CoCuAl-layered double oxides was synthesized from CoCuAl-layered double hydroxides. The prepared CoCuAl-LDOs possessed high purity, uniform morphology, and a large special surface area (103.8 m2/g). CoCuAl-LDOs is an efficient catalyst for activating peroxymonosulfate (PMS) to degrade organic pollutants. Acid orange 7 (AO7, 20 mg/L) can be completely degraded within 30 min using 0.1 g/L CoCuAl-LDOs and 0.1 g/L PMS. The CoCuAl-LDOs/PMS system also exhibited good performance over a wide pH range. SO4 •– was identified as the main reactive species responsible for pollutant degradation. More importantly, the structure–property relationship was investigated by H2-TPR and XPS. It was found that the high performance of CoCuAl-LDOs is attributed to the Co–Cu synergistic effect which can accelerate the redox cycle of Co2+/Co3+. This study sheds light on the Co–Cu synergistic effect for developing catalyst with high performance toward activating PMS in environmental remediation.