Foams stabilized by mixed cationic gemini/anionic conventional surfactants

The mixed adsorption of a cationic gemini surfactant, ethanediyl-1,2-bis(dodecyldimethylammonium bromide) (abbreviated as 12-2-12), and an anionic conventional surfactant, sodium dodecyl sulfate (SDS), was examined using surface tension measurements. The viscoelastic properties of the mixed films were investigated by dilational interfacial rheology technique. The results showed that the addition of SDS promoted the close packing of adsorbed molecules at the interface, which increased the dilational elasticity of the mixed films. The stability of the foams was determined by the half-life of foam height collapse. The foams generated by 12-2-12/SDS mixtures were more stable than that formed by pure 12-2-12. In the presence of sodium bromide, the foam stability was further enhanced and the surfactant concentration required to attain the maximum effect in stabilizing foams was greatly reduced. The high foam stability could well relate to the high elasticity of the film.     

Synthesis of TiO2/Bi2WO6 nanofibers with electrospinning technique for photocatalytic methyl blue degradation

TiO₂/Bi₂WO₆ composite nanofibers have been successfully synthesized by a simple electrospinning process. XRD, SEM, HR-TEM, nitrogen adsorption–desorption isotherms and UV–visible diffuse reflectance spectra were used to characterize the composite nanofibers. The composite fibers with diameters about 100 nm was composed of nanoparticles and possessed of high specific surface area (49.6 m² g^?1) and porous structure. Besides, the TiO₂/Bi₂WO₆ composite nanofibers exhibited excellent visible photocatalytic property in the photodegradation of methylene blue (MB), and over 97.2 % of MB was degraded within 5.5 h.     

Simultaneous characterization and quantification of flavonoids in Euonymus alatus (Thunb.) Siebold from different origins by HPLC-PAD–MS

A high-performance liquid chromatography coupled with photodiode array detection and electrospray ionization tandem mass spectrometry (HPLC-PAD–ESI-MS) method has been developed for the simultaneous identification and quantification of active compounds (rutin and quercetin) contained in Traditional Chinese Medicine (TCM) Euonymus alatus (Thunb.) Siebold (EAS). The herb samples from ten main origins and five medicinal portions (leaf, fruit, stem, pterygium and root) were investigated. The separation was performed on a Shim C₁₈ column at 30 °C with an isocratic elution. Methanol (A) and water (0.5% methanoic acid, v/v) (B) were used as mobile phases. The recoveries of the two compounds were 100.184% and 100.417%, respectively, and all of them showed good linearity (r² ? 0.9993) in relatively wide concentration ranges. The developed method was applied to identify and quantify the two major active compounds in the collected herb samples, and the results indicated that contents of the two compounds in EAS varied significantly from habitat to habitat. It was demonstrated that the proposed method was helpful for the quality evaluation of EAS.     

多相催化反应原位红外系统及其应用

设计和建立了一套能耐高温的用于多相催化反应研究的原位红外系统，反应温度从室温到１１５０Ｋ，系统真空为１．０＊１０＾５－１．０－１０＾－４Ｐａ，红外光谱检测范围为４８００－２００ｃｍ＾－１。此系统扩展了原仪器的功能，提高了仪器利用率和效率。     

Chitooligosaccharide Copolymers: Synthesis and Aqueous Self-assembly

Novel water-soluble amphiphilic graft copolymers (COS-g-PCL-b-MPEG) were synthesized by the coupling reaction between chitooligosaccharide (COS) and MPEG-b-PCL-COOH, which was synthesized via ring-opening polymerization of ε-caprolactone (CL) using MPEG as an initiator and subsequent carboxylation by succinic anhydride. The chemical composition of the graft copolymers was confirmed by ¹H-NMR spectra and FT-IR spectrometry. The thermal properties and crystallinity of the copolymers were observed by DSC and XRD measurements, which showed the existence of separate backbone and graft chain phases in the copolymer. The micellar behavior via self-assembly of the graft copolymers in aqueous solution was studied using pyrene fluorescence dye technique. AFM measurements showed that the micelles had a spherical morphology at the critical micelle concentration (CMC) and ranged in size from 20–45 nm. The amphiphilic ternary biodegradable graft copolymer endows the hydrophilic outer shell of micelles with structural and functional diversification, which might be desirable for drug delivery applications.     

Synthesis and enantioselective fluorescent sensors for amino acid derivatives based on BINOL

Four novel derivatives of 1,1′-bi-2-naphthol have been prepared and the structures of these compounds characterised by IR, MS, ¹H and ¹³C NMR spectroscopy and elemental analysis. The enantioselective recognition of these sensors has been studied by fluorescence titration and ¹H NMR spectroscopy. The sensors exhibited different chiral recognition abilities towards N-Boc-protected amino acid anions and formed 1:1 complexes between the host and the guest. Sensors exhibit excellent enantioselective fluorescent recognition ability towards the amino acid derivatives.     

The Investigation of Interaction Competition Between ATP and DIPP-Ala,Boc-Ala,or Ala by ESI-MS/MS and Theoretical Calculation

The interactions between ATP and N-(O,O-diisopropyl) phosphoryl-L-alanine (DIPP-Ala), N-(tert-butoxycarbonyl)-L-alanine (Boc-Ala), or L-alanine (Ala) were investigated by electrospray ionization tandem mass spectrometry (ESI-MS/MS). The non-covalent complexes between ATP and Boc-Ala or DIPP-Ala were observed, while the complex between ATP and Ala was not found in the mass spectra. The affinity of DIPP-Ala for ATP was confirmed to be stronger than that of Boc-Ala by competition experiment. Through molecular modeling calculations, it was found that the non-covalent complexes were stabilized by intermolecular hydrogen bonds, and the affinity sequence for ATP was DIPP-Ala > Boc-Ala > Ala by comparing their binding energy, ?35.407 kcal/mol, ?15.634 kcal/mol, ?6.555 kcal/mol, respectively. The results implied that a phosphoryl group was a very important functional group to provide an interaction site between amino acids and ATP, and that N-phosphoryl amino acids can be used as a good model of protein in the studies of molecular recognition of ATP.     

Phenol-formaldehyde resin route to the synthesis of several iron group transition metal phosphides

Abstract

A series of iron, cobalt and nickel metal phosphides of chemical formula Fe_xP, Co₂P and Ni₂P with high specific surface areas of 331.1, 294.2 and 228.0 m² g^?1, respectively, was firstly synthesized by phenol-formaldehyde resin route. It was found that the as-prepared Co₂P and Ni₂P samples synthesized using phenol-formaldehyde resin as a carbon source showed much higher BET surface areas than those prepared using other carbon sources reported before, including cinnamic strong alkali anion exchange resin, p-phenylenediamine and hexamethylenetetramine. This phenol-formaldehyde resin route was proved to be as universal as traditional H₂ reduction method.     

Photocatalytic Activity of High Aspect Ratio TiO2 Nanorods

In this article, TiO₂ nanorods (aspect ratio >20) were prepared through a polyol process and doped with metal ions (Cu²⁺, Ni²⁺, Fe³⁺, and Cr³⁺). Compared with TiO₂ nanoparticles, the TiO₂ nanorods displayed relatively higher photocatalytic activity for the degradation of copper sulfophthalocyanine. Moreover, the photocatalytic activity was greatly enhanced when the metal ions were doped in the TiO₂ nanorods.     

Electrical Property of Tin Oxide Doped with Multi‐Walled Carbon Nanotubes

Tin oxide doped with multi‐walled carbon nanotubes (MWNTs) was prepared via a wet‐chemical process and characterized with x‐ray diffraction (XRD) and transmission electron microscope (TEM). Meanwhile, the conductivity of composites obtained was measured using Source Meter. The results show that carbon nanotubes have great effect on the electrical property of SnO₂ nanoparticles. Compared with undoped SnO₂ nanoparticles, the resistivity of SnO₂ nanoparticles doped with 0.3‰ wt MWNTs decreased by a factor of 37. This may be ascribed to the presence of π energy levers of MWNTs and their high aspect ratio. Moreover, the effect of annealing temperature on the electrical property of SnO₂ nanoparticles doped with MWNTs also was discussed.