The solubilities of sodium 1- and 2-naphthalenesulfonate (1- and 2-SNS) in aqueous sodium hydroxide solutions were measured over the temperature range from 276 to 337 K at atmospheric pressure by a dynamic method. The experimental results showed that the solubilities of 1- and 2-SNS both increased with temperature and decreased with concentrations of aqueous sodium hydroxide solutions. The experimental data were correlated with the new electrolyte nonrandom two-liquid (E-NRTL) model. The calculated results showed good agreement with the experimental data. A new strategy, based on the solubility difference between 1- and 2-SNS in aqueous sodium hydroxide solutions, was carried out in laboratory scale. This new strategy, in which the current process of blowing naphthalene was replaced by removing the byproduct according to the solubility difference, overcame the drawbacks of blowing naphthalene and made a good separation effect. The best separation effect was attained when the concentration of aqueous sodium hydroxide solution was 0.07 and the operating temperature was 298.15 K. The purities of obtained 1- and 2-SNS were 0.8369 and 0.9854 in this operating condition, respectively. The new strategy has potential in industrial application for optimizing the production of 2-naphthol.

To achieve remote control over the swelling/deswelling transition, chemically exfoliated MoS2 nanosheets with photothermal properties are successfully incorporated into poly(N-isopropylacrylamide) (PNIPAM) hydrogel by in situ polymerization. Different from the conventional thermal-responsive PNIPAM hydrogel, the MoS2/PNIPAM composite hydrogel here shows a reversible volumetric change in response to near-infrared (NIR) illumination. Based on this new composite hydrogel, a microfluidic device actuated remotely by NIR laser is also demonstrated.

•Cu2O–MoS2/graphene composite was successfully prepared by a facile two-step process.•Cu2O–MoS2/graphene shows superior photcatalytic activity for CC bond formation.•Synergetic effects of MoS2 and graphene enhanced the catalytic activity of Cu2O.Visible light driven photoredox catalysis has considered as a sustainable and promising strategy for organic synthesis. Here we report a new composite material consisting of cuprous oxide (Cu2O) nanoparticles grown on layered molybdenum disulfide (MoS2) and graphene hybrids as a high-performance photocatalyst for CC bond formation reaction. This composite material shows superior stability and reusability. The enhanced photocatalytic activity of the novel catalyst is attributed to the synergetic effects of MoS2 and graphene as cocatalysts in the composite, in which graphene serves as an excellent electron transporter, and MoS2 nanosheets provide a source of active sites. This work would open a promising way to design and fabricate the efficient composite photocatalysts for organic synthesis.Download high-res image (103KB)Download full-size image

Semiconductors are the low cost and recyclable photocatalysts for visible-light photoredox catalysis, which is one of the prospective ways to convert solar energy to chemical energy in organic synthesis. This study reports a new MoS2/ZnO composite for the aerobic oxidation of benzyl halides under visible light. Despite the limited intrinsic activity of the ZnO alone, we found that the introduction of a small amount of MoS2 nanosheets (4 wt %) could significantly improve the catalytic performances of the ZnO in visible-light photoredox catalysis.

In this study, we synthesized a novel composite material (Au–TiO2–RGO) consisting of tiny gold nanoparticles (∼4.5 nm) grown on a layered titania (TiO2) and reduced graphene oxide (RGO) hybrid. After treatment with microwave and sulfuric acid, solid acid (SO42−/TiO2) was in situ formed on the surface of TiO2, and the resulting Au–SO42−/TiO2–RGO was determined as an enhanced catalyst for hydration reaction. The strong metal-support interaction (SMSI) between Au and TiO2 and the cooperative effect between Au and SO42−/TiO2 solid acid collectively account for the excellent performance. Moreover, due to the versatile RGO substrate, the catalyst could also be recycled and reused at least 5 times without obvious deactivation.

The solubility of disodium 4,4′-dinitrobibenzyl-2,2′-disulfonate (DNDNa) in aqueous ethylene glycol monoethyl ether solution and aqueous ethylene glycol monobutyl ether solution was measured over the temperature range from 278 to 334 K at atmospheric pressure by a dynamic method. The solubility of DNDNa in aqueous ethylene glycol monoethyl ether solution and aqueous ethylene glycol monobutyl ether solution increased with temperature over all solvent mixture compositions investigated. A synergistic effect on DNDNa solubility was observed with the maximum solubility at solute-free mass fraction of ethylene glycol monoethyl ether w30=0.6003 and solute-free mass fraction of ethylene glycol monobutyl ether w40=0.4054 , respectively. The solubility data were correlated using the electrolyte non-random two-liquid model and model parameters were determined simultaneously. It was found that around 0.4 (solute-free mass ratio) ethylene glycol monobutyl ether solution is suitable as the reaction medium in oxidation 4-nitrotoluene-2-sulfonic acid to 4,4′-dinitrostilbene-2,2′-disulfonic acid. The effect of different aqueous organic solutions on the oxidation reaction was discussed.

HPLC and electrospray ionization tandem mass spectrometry were used to show that ∼30% of the DNS present in wastewater was reduced to 4-amino-4′-nitrostilbene-2,2′-disulfonic acid and 4,4′-diaminostilbene-2,2′-disulfonic acid during multiple-effect evaporation. A novel recovery method, which combines acidification and subsequent reduction, recovered of ∼90% of the DNS that is lost during evaporation and, thereby, increased the yield of 4,4′-diaminostilbene-2,2′-disulfonic acid by 5%. In addition, many of the organic compounds present in the wastewater were removed.

Magnetic multi-walled carbon nanotube (MWCNT) composites were obtained by decoration of metal oxide nanoparticles on or in carbon nanotubes. The method involved the dispersion of the carbon nanotubes in iron pentacarbonyl Fe(CO)5 followed by vacuum thermolysis and subsequent oxidation. The magnetic iron oxide particle deposition was always homogeneous and could be controlled selectively on the outer, inner, or both surfaces of MWCNTs by using different MWCNTs. Since the hollow channels remained intact, these MWCNT based composites could find special applications in cellular delivery systems.

Magnetic γ-Fe2O3-MWCNTs hybrids possess a wide range of potential applications. This paper reports a novel and efficient method to fabricate the magnetic γ-Fe2O3-MWCNTs hybrids, via the vacuum thermolysis of Fe(CO)5 confined in/around MWCNTs and subsequent controlled oxidation. It was found that γ-Fe2O3 nanoparticles with controllable sizes could be uniformly nucleated on both the inner and outer surfaces of MWCNTs. The mean sizes of the γ-Fe2O3 nanoparticles here can be varied from 6 to 15 nm by simply modify the experimental process, rendering the hybrids tunable magnetic properties from ferromagnetism to superparamagnetism. It was demonstrated that this method could be used to obtain various metals/oxides-MWCNTs hybrids by simply substituting the metal carbonyl precursors.