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The results presented in this work give new insights into the molecular mechanism of crystallization nucleation for conformational polymorphic systems. It can be used to regulate conformational polymorphism., Nucleation of crystals from solution is fundamental to many natural and industrial processes. In this work, the molecular mechanism of conformational polymorphism nucleation and the links between the molecular conformation in solutions and in crystals were investigated in detail by using 5-nitro­furazone as the model compound. Different polymorphs were prepared, and the conformations in solutions obtained by dissolving different polymorphs were analysed and compared. The solutions of 5-nitro­furazone were proven to contain multiple conformers through quantum chemical computation, Raman spectra analysis, 2D nuclear Overhauser effect spectroscopy spectra analysis and molecular dynamics simulation. The conformational evolution and desolvation path was illustrated according to the 1H NMR spectra of solutions with different concentrations. Finally, based on all the above analysis, the molecular conformational evolution path during nucleation of 5-nitro­furazone was illustrated. The results presented in this work shed a new light on the molecular mechanism of conformational polymorphism nucleation in solution.

A series of hexadecylphosphate acid (HDPA) terminated mixed-oxide nanoparticles have been investigated to catalyze the oxidation of toluene exclusive to benzaldehyde under mild conditions in an emulsion of toluene/water with the catalysts as stabilizers. With the HDPA-Fe2O3/Al2O3 as the basic catalyst, a series of transition metals, such as Mn, Co, Ni, Cu, Cr, Mo, V, and Ti, was respectively doped to the basic catalyst to modify the performance of the catalytic system, in expectation of influencing the mobility of the lattice oxygen species in the oxide catalysts. Under normally working conditions of the catalytic system, the nanoparticles of catalysts located themselves at the interface between the oil and water phases, constituting the Pickering emulsion. Both the doped iron oxide and its surface adsorbed hexadecylphosphate molecules were essential to the catalytic system for excellent performances with high toluene conversions as well as the exclusive selectivity to benzaldehyde. Under optimal conditions, ∼83% of toluene conversion and >99% selectivity to benzaldehyde were obtained, using molecular oxygen as oxidant and HDPA-(Fe2O3-NiO)/Al2O3 as the catalyst. This process is green and low cost to produce high quality benzaldehyde from O2 oxidation of toluene.

In this work, to simultaneously remove organic dyes and Pb(II) from wastewater, a series of magnetic Fe3O4@C@TiO2-nanotube composites were designed and successfully synthesized via a new facile oil-phase cyclic magnetic adsorption (OCMA) method. The structural properties of the synthesized composites were investigated by different characterization methods systematically. It was found that Fe3O4 was uniformly deposited on the inner walls of TiO2 nanotubes. Although a Type III band alignment was formed in the catalysts, Fe3O4@C@TiO2-nanotube composites exhibited enhanced light absorbing ability and enlarged absorption edge due to efficient separation of h+ and e−, which was verified by UV–Vis (Ultraviolet–visible) and PL (Photoluminescence) spectra. Decontamination experiments of 1FeCTi showed that more than 98% of RhB and about 92% of Pb(II) ions could be removed through adsorptive removal in the dark equilibrium period and further elimination during the illuminating period. The pseudo-first-order model, L-H model and adsorption-reaction model were established to describe the adsorption of Pb(II) in the dark, photodegradation of RhB and further elimination of Pb(II), respectively. A four-step mechanism was proposed to describe the decontamination process of Pb(II) during the illuminating period according to the final forms of Pb (Pbδ1, Pbδ2, Pb0 and PbO). Finally, it was found that the photocatalytic activity would be maintained in the recycle experiments due to the existence of 1FeCTi@PbO heterostructure.

In this work, to help the development and design of separation and purification processes for tris-(2,4-ditert-butylphenyl)-phosphite which is an antioxidant of plastic processing, its solution thermodynamics was investigated. Using a static gravimetric method, solubilities of tris-(2,4-ditert-butylphenyl)-phosphite in twelve pure solvents (including acetone, ethyl acetate, methyl acetate, ethyl formate, isopropyl acetate, butyl acetate, n-hexane, n-heptane, n-octane, isooctane, propyl acetate and ethyl butyrate) were measured at temperatures varying from 278.15 K to 323.15 K. It was found that, in all investigated solvents, the solubility data of tris-(2,4-ditert-butylphenyl)-phosphite increased with the increasing of temperature over the entire investigated temperature range. The modified Apelblat equation, the λh equation and the NRTL model were employed to correlate the solubility data. The computed data showed that the modified Apelblat equation correlated the solubility data better. Moreover, the mixing and dissolution thermodynamic properties of tris-(2,4-ditert-butylphenyl)-phosphite in various pure solvents were also calculated according to the NRTL model and the experimental solubility data.

To gain further insights into the formation of cocrystals, the thermodynamic mechanism and molecular recognition process of cocrystal formation were investigated by using p-hydroxybenzoic (PHBA) as the model compound. One new 1 : 1 (molar ratio) cocrystal of p-hydroxybenzoic (PHBA) and glutaric acid (GA) was successfully synthesized via several methods, including liquid-assisted grinding, cooling crystallization, and slurry conversion crystallization. The prepared cocrystal powder was characterized by PXRD, DSC and Raman spectroscopy. The crystal structure of the cocrystal was determined and interpreted by single-crystal XRD. The ternary phase diagrams of the newly prepared cocrystal were constructed in acetonitrile at three temperatures, i.e., 2, 20 and 40 °C. The temperature was shown to have an impact on the shape of the ternary phase diagrams. Guided by the determined ternary phase diagrams, the pure PHBA–GA cocrystal could be prepared successfully by isothermal slurry conversion crystallization. Raman spectroscopy was employed to monitor the molecular recognition and self-assembly process of the conversion in situ. In addition, density functional theory calculations were conducted to determine the stability and interaction energy of the cocrystal, rationalizing the formation potential of the PHBA–GA cocrystal.

In this study, a novel magnetic nanoparticles (MNP) modified by an organodisulfide polymer (PTMT) was designed for adsorption of heavy metals (Hg(II), Pb(II) and Cd(II)) from simulated coal chemical high salinity wastewater. The MNP-PTMT nano-composite was synthesize and characterized by SEM, TEM, FTIR, BET, VSM, TGA and XRD. The results indicate that the wanted MNP-PTMT magnetic nanoparticles were successfully obtained by modification. Adsorption experiments were systematically carried out to evaluate the performance of the obtained nanoparticles and to build up the adsorption models. The results demonstrate that the adsorption kinetic and isotherms thermodynamic followed the pseudo-second-order model and the Freundlich equation, respectively. In the presence of the inorganic salt in high salinity wastewater, the adsorption efficiency of MNP-PTMT for heavy metals was still excellent. The magnetic adsorbent could be recovered from aqueous solution by an external magnetic field in 20s and the subsequent regeneration of Hg(II)/Pb(II) loaded MNP-PTMT can be efficiently achieved by using EDTA-2Na solution as desorbent. The novel MNP-PTMT nanoparticles could be used reproductively for five times without apparent decrease in sorption capacity.

A series of tetraphenylethene-borondipyrromethene (TPE-BODIPY) derivatives with different numbers of methyl groups on BODIPY cores were designed and synthesized. The intramolecular charge transfer behaviors from donor TPE to accepter BODIPY were investigated. Aggregation-induced emission (AIE), theoretical calculation, single crystal structure and solvent effect all proved that the introduction of methyl group to BODIPY can inhibit the intramolecular charge transfer behavior. Red organic luminescent material 8-TPEBODIPY (TPB) with no methyl groups showing twisted intramolecular charge transfer (TICT) emission peak both in solution and in film state, presents obviously AIE and solvatochromic properties and a large Stokes shifts over 100 nm, which can be employed as a fluorescent sensor for the detection of water in THF.

Background: In the pharmaceutical field, it is vital to ensure a consistent product containing a single solid-state form of the active pharmaceutical ingredient (API) in the drug product. However, some APIs are suffering from the risk of transformation of their target forms during processing, formulation and storage. Methods: The purpose of this review is to summarize the relevant category of excipients and demonstrate the availability and importance of using excipients as a key strategy to manipulate pharmaceutical polymorphic transformation. Results: The excipient effects on solvent-mediated phase transformations, solid-state transitions and amorphous crystallization are significant. Common pharmaceutical excipients including amino acids and derivatives, surfactants, and various polymers and their different manipulation effects were summarized and discussed. Conclusion: Appropriate use of excipients plays a role in manipulating polymorphic transformation process of corresponding APIs, with a promising application of guaranteeing the stability and effectiveness of drug dosage forms.

Hydrogen-bonded frameworks (HOFs), which are constructed from organic moieties via hydrogen bonding, represent an emerging attractive class of porous crystalline materials. Though HOFs have exhibited varieties of merits such as solution processability, highly-crystalline structure, good recyclability, easy purification etc., the flexible and weak feature of hydrogen bonds usually makes the HOFs vulnerable and difficult to maintain the permanent porosity, which greatly hampers the development and application of this kind of materials. In this work, some basic rules to construct HOFs with permanent porosity and good stability are summarized. Moreover, the major applications of HOFs are highlighted in this review, including the gas storage/separation, proton conduction, catalysis, luminescent materials, biotechnology etc. Specifically, some latest developments and discoveries in this area are summarized and discussed. Finally, the promising perspectives of HOFs are also discussed and the potential directions for future work are suggested.

Removal of contaminants in wastewater, such as heavy metals, has become a severe problem in the world. Numerous technologies have been developed to deal with this problem. As an emerging technology, nanotechnology has been gaining increasing interest and many nanomaterials have been developed to remove heavy metals from polluted water, due to their excellent features resulting from the nanometer effect. In this work, novel nanomaterials, including carbon-based nanomaterials, zero-valent metal, metal-oxide based nanomaterials, and nanocomposites, and their applications for the removal of heavy metal ions from wastewater were systematically reviewed. Their efficiency, limitations, and advantages were compared and discussed. Furthermore, the promising perspective of nanomaterials in environmental applications was also discussed and potential directions for future work were suggested.

In this work, solubility data of ceftezole in seven pure solvents and two binary solvent systems were experimentally measured via a static gravimetric method in the temperature range from 278.15 K to 313.15 K under atmospheric pressure. The results indicated that the solubility of ceftezole in all the selected pure and binary solvent systems increased with the rising of temperature. It was also found that the solubility order of ceftezole in the seven mono-solvents was generally ranked as: water

The solubility data of cefradine in different solvent systems as a function of pH were determined by dynamic method. The effect of pH and solvent compositions on the solubility data and the isoelectric points were evaluated and discussed. It was found that the solubility data of cefradine are consistent with the dissolution property of ampholyte, whether in mono-solvent or binary mixed solvent, which has a large solubility at large pH and small pH values and the solubility curves exhibit U shapes. The isoelectric points of cefradine in different solvent systems were also determined and discussed. Two theoretical models were used to correlate the experimental solubility data. It was found that model I can give better correlation results.

In this work, solution thermodynamic properties including solubility, mixing thermodynamic properties and dissolution thermodynamic properties are investigated in detail. Gravimetric method was utilized for measuring the solubility data of flurbiprofen in twelve pure solvents including n-propanol, isopropanol, n-butanol, isobutanol, isopentanol, isopropyl acetate, methyl tert-butyl ether, isopropyl ether, acetonitrile, n-octane, n-heptane and n-hexane over the temperatures range from 283.15 to 323.15 K under atmospheric pressure. The results indicated that the solubility of flurbiprofen increased with the increasing temperature. Furthermore, the experimental solubility data were correlated by the modified Apelblat equation, λh equation, Wilson model and NRTL model. And the modified Apelblat equation can give better correlation results with lower values of ARD%. Moreover, mixing and dissolution thermodynamic properties of flurbiprofen in different solvents were calculated according to the experimental data and the NRTL model.