N,N-二烯丙基甲基胺的相转移催化合成

相转移催化剂;聚乙二醇-400;N;N-二烯丙基甲基胺的相转移催化合成     

微波固相反应制备CdS纳米粒子

硫化镉是一种重要的半导体材料,在太阳能转化、非线形光学、光电子化学电池和光催化方面具有广泛的应用[1,2]。近十年以来,人们已经使用了许多的方法来制备纳米硫化镉[3~7]。由于微波能同时促进吸热反应和放热反应,对化学反应具有催化作用,可降低反应的温度,从而为化学反应创造     

Indirect Speciation Analysis of Thallium in Plant Extracts by Anodic Stripping Voltammetry

A sensitive voltammetric method (DPASV) was developed for the determination of Tl(I) and Tl(III) in plant extracts. To limit the influence of the organic matrix on the measurements, UV irradiation and addition of Amberlite XAD‐7 resin was studied. The application of 0.5 g of the resin allowed defining thallium speciation in 10.0 mL of a solution containing 0.20 mL of Sinapis alba extract. The quantification limit of 0.5 ng mL^?1 Tl(I) was found for only 10 min of preconcentration, and is low enough to allow dilution of the sample before thallium determination. The procedure was validated using the recovery study and intermethod comparison with HPLC ICP MS.     

Practical,Ecofriendly, and Chemoselective Method for the Synthesis of 2-Aryl-1-arylmethyl-1H-benzimidazoles Using Amberlite IR-120 as a Reusable Heterogeneous Catalyst in Aqueous Media

A simple, efficient, and environmentally benign method has been developed for the exclusive formation of biologically significant 2-aryl-1-arylmethyl-1H-benzimidazoles under the heterogeneous catalysis of Amberlite IR-120 in aqueous media in excellent yields. The catalyst is recyclable without loss of activity.     

Novel Synthesis of Linear Furonaphthoquinones

An efficient synthesis of naturally occurring and biologically active furonaphthoquinones is described starting from suitably substituted dihydronaphthofuraps.     

Paal–Knorr Pyrrole Synthesis Using Recyclable Amberlite IR 120 Acidic Resin: A Green Approach

Amberlite IR 120 acidic resin, a polymer matrix, has been demonstrated as a catalyst for Paal-Knorr condensation of 2,5-hexadione with primary amines under solvent-free conditions. This is an efficient, mild, and green methodology for N-substituted pyrrole derivatives.     

Copper(I) salt/PEG‐400 catalysis in one‐pot direct synthesis of 1‐aryl‐1H‐indazoles from 2‐bromobenzaldehydes and arylhydrazines

2‐Bromobenzaldehydes are condensed and cyclized with arylhydrazines (or their hydrochlorides) in PEG‐400 at 110 °C in the presence of a catalytic amount of a copper(I) salt along with a base to give 1‐aryl‐1H‐indazoles in high yields. Copyright © 2013 John Wiley & Sons, Ltd.     

PROPERTIES OF SILK FIBROIN/POLY(ETHYLENE GLYCOL)400 BLEND FILMS

The blend film of silk fibroin (SF) and poly(ethylene glycol)400 (PEG400) with a blend ratio of 2/1 (wt/wt) wasprepared simply by dropping a little PEG400 into the SF solution and then casting the mixed aqueous solution at 50℃. Theresulting film exhibited much better mechanical properties in the dry and wet state than SF itself, owing to theconformational change of SF in the blends from the random coil to the β-sheet structure and intermolecular hydrogen bondformation between SF and PEG400. Thermogravimetric analysis showed that the initial thermal decomposition temperatureof the blend film was 170℃, which was 80℃ lower than that of SF (250℃) and 20℃ higher than that of PEG400 (150℃),and indicated a Strong interaction between two components of the blend. No crystalline peaks were observed in the X-raydiffraction curve of the blend film. Cell culture test showed that SF/PEG400 was a suitable substrate for the growth of humanumbilical vein endothelial cells (HUVEC).     

Sorption of Lead(II) on Two Chelating Resins: From the Exchange Coefficient to the Intrinsic Complexation Constant

The sorption of inorganic lead(II) on two cationic resins containing different complexing groups, the iminodiacetic Chelex 100 and the carboxylic Amberlite CG-50, was investigated. The Gibbs-Donnan model was used to describe and predict the sorption through the determination of the intrinsic complexation constants. These quantities, even though non-thermodynamic, characterize the sorption as being independent of experimental conditions. The sorption mechanism for metals on complexing resins was also studied by adding a competitive soluble ligand that shifts the sorption curves to higher pH. The ligand competes with the resin for complexation with the metal ion. Lead(II) is strongly sorbed on Chelex 100 through the formation of two complexes in the resin phase: MHL with log ₁₀ β _111i =−0.3 and ML with log ₁₀ β _111i =−3.7. The presence of the competitive ligand in solution allows for the determination of a third complex. Furthermore, on Amberlite CG-50 the sorption is rather strong and involves the formation of the complex ML, in more acidic solution, with log ₁₀ β _110i =−2.0. In the presence of the ligand PyDA, the ML(OH) complex was characterized by log ₁₀ β _11−1i =−5.6. In all the experiments the hydrolysis reactions in the aqueous phase are considered quantitatively.     

PEG-400 promoted Pd(OAc)2/DABCO-catalyzed cross-coupling reactions in aqueous media

PEG-400 [poly(ethylene glycol-400)] was found to improve the Pd(OAc)₂/DABCO-catalyzed aqueous Suzuki-Miyaura and Stille cross-coupling reactions. In the presence of Pd(OAc)₂, DABCO, and PEG-400, a variety of aryl halides were coupled with arylboronic acids or organotin compounds efficiently to afford the corresponding cross-coupled products in moderate to excellent yields. The turnover numbers was up to 900,000 for the Suzuki-Miyaura reaction and up to 9800 for the Stille reaction. The catalyst system was also effective for Heck and Sonogashira cross-coupling reactions to some extent.