环三藜芦烃的分子识别与组装

环三藜芦烃是一类基于藜芦醚与甲醛缩聚物的大环主体分子,其具有独特的C3对称结构和刚性的富电子空腔,在超分子化学、材料科学等方面具有潜在的应用价值,受到人们越来越多的重视.本文主要概述了近年来环三藜芦烃及其衍生物在分子识别与超分子组装方面的一些研究进展.     

Effects of Sludge Concentrations and Different Sponge Configurations on the Performance of a Sponge-Submerged Membrane Bioreactor

The performance of a novel sponge-submerged membrane bioreactor (SSMBR) was evaluated to treat primary treated sewage effluent at three different activated sludge concentrations. Polyurethane sponge cubes with size of 1?×?1?×?1?cm were used as attached growth media in the bioreactor. The results indicated the successful removal of organic carbon and phosphorous with the efficiency higher than 98% at all conditions. Acclimatised sponge MBR showed about 5% better ammonia nitrogen removal at 5 and 10?g/L sludge concentration as compared to the new sponge system. The respiration test revealed that the specific oxygen uptake rate was around 1.0?C3.5?mgO₂/gVSS.h and likely more stable at 10?g/L sludge concentration. The sludge volume index of less than 100?mL/g during the operation indicated the good settling property of the sludge. The low mixed liquor suspended solid increase indicated that SSMBR could control the sludge production. This SSMBR was also successful in reducing membrane fouling with significant lower transmembrane pressure (e.g. only 0.5?kPa/day) compared to the conventional MBR system. Further study will be conducted to optimise other operating conditions.     

Synthesis and NMR Spectroscopic Characteristics of a Series of Hydrazide‐Hydrazones Containing Furoxan Ring Derived from Isoeugenoxyacetic Acid

A novel hydrazide, 2‐methoxy‐4‐(3‐methyfuroxan‐4‐yl)‐5‐nitrophenoxyacetylhydrazine, was prepared from isoeugenoxyacetic acid. The hydrazide was condensed with aromatic aldehydes to give a series of 20 hydrazide‐hydrazones incorporating the furoxan ring. The structure of obtained compounds was determined by analytical and spectral data. It was demonstrated that the two sets of resonance signals in the ¹H‐NMR and ¹³C‐NMR spectra of the examined hydrazide‐hydrazones are caused by E_N–C(O) and Z_N–C(O) conformers. The energy barriers for the conformation exchange were determined by ¹H‐NMR‐measurement at various temperatures. Among seven tested hydrazide‐hydrazones, four compounds exhibit inhibition activities in vitro on human epidermis carcinoma (KB‐cell) with IC₅₀ = 47, 68, 79, and 103 μg/mL.     

Determination of unreacted 2,4-toluene diisocyanate (2,4TDI) and 2,6-toluene diisocyanate (2,6TDI) in foams at ultratrace level by using HPLC-CIS-MS-MS

Isocyanates can cause occupational asthma. By using available HPLC-UVF methods, isocyanates can be quantified only at levels above 1% of the Permissible Exposure Limits (PEL). Once sensitized, workers can react to concentrations below these limits of detection (LOD) making these methods insufficiently sensitive to adequately evaluate trace amounts of isocyanates present in air or in materials at safe levels for sensitized workers. This article describes a novel method for isocyanate analysis allowing the quantification of 2,4TDI and 2,6TDI monomers at very low concentrations using HPLC-CIS-MS-MS. The method's sensitivity increases with a decrease in the alkali radius. The LOD is 0.039 ng mL(-1) for 2,4TDI and 0.100 ng mL(-1) for 2,6TDI in solution when lithium is the alkali adduct, which is 20 times more sensitive than HPLC-UVF method. This new method allows determination in foam at levels of 0.078 ng g(-1) for 2,4TDI and 0.200 ng g(-1) for 2,6TDI respectively, for a 0.5 g foam sample. This is more than 100 times more sensitive than other methods for determining free monomers in solid materials. Analytical reproducibility and precision are better than 92% and 93% for both diisocyanate monomers. The use of HPLC-UVF conventional method failed to detect unreacted isocyanates in foam samples, but TDI monomers were quantified by HPLC-CIS-MS-MS.     

From Enantiopure Hydroxyaldehydes to Complex Heterocyclic Scaffolds: Development of Domino Petasis/Diels–Alder and Cross‐Metathesis/Michael Addition Reactions

One‐step assembly of hexahydroisoindole scaffolds by a sequence that combines the Petasis (borono‐Mannich) and Diels–Alder reactions is described. The unique selectivity observed experimentally was confirmed by quantum calculations. The current method is applicable to a broad range of substrates, including free sugars, and holds significant potential to efficiently and stereoselectively build new heterocyclic structures. This easy and fast entry to functionalized polycyclic compounds can be pursued by further transformations, for example, additional ring closure by a cross‐metathesis/Michael addition domino sequence.     

Synthesis of partially fluorinated poly(arylene ether sulfone) multiblock copolymers bearing perfluorosulfonic functions

Partially fluorinated poly(arylene ether sulfone) multiblock copolymers bearing perfluorosulfonic functions (ps‐PES‐FPES), with ionic exchange capacity (IEC) ranging between 0.9 and 1.5 meq H⁺/g, are synthesized by regioselective bromination of partially fluorinated poly(arylene ether sulfone) multiblock copolymers (PES‐FPES), followed by Ullman coupling reaction with lithium 1,1,2,2‐tetrafluoro‐2‐(1,1,2,2‐tetrafluoro‐2‐iodoethoxy)ethanesulfonate. The PES‐FPES are prepared by aromatic nucleophilic substitution reaction by an original approach, that is, “one pot two reactions synthesis.” The chemical structures of polymers are analyzed by ¹H and ¹⁹F NMR spectroscopy. The resulted ionomers present two distinct glass transitions and α relaxations revealing phase separation between the hydrophilic and the hydrophobic domains. The phase separation is observed at much lower block lengths of ps‐PES‐FPES as compared with the literature. AFM and SANS observations supported the phase separation, the hydrophilic domains are well dispersed but the connectivity to each other depends on the ps‐PES block lengths. The thermomechanical behavior, the water up‐take, and the conductivity of the ps‐PES‐FPES membranes are compared with those of Nafion 117^® and randomly functionalized polysulfone (ps‐PES). Conductivities close or higher to those of Nafion 117^® are obtained. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1941–1956     

Estimation of radon and thoron caused dose at exraction and processing sites of mineral sand mining area in Vietnam (HA TINH province)

Mineral sands are mined in several countries to supply to the titanium and zircon producing industries. Coastal black mineral sands usually contain, besides ilmenite (FeTiO₃) and rutile (TiO₂), radioactive minerals such as zircon (ZrSiO₄) and monazite (RePO₄). Radon and thoron activity concentration originated from natural radioactive contents of the black mineral sand was monitored at the extraction and processing for black minerals in the coastal areas of Ha Tinh Province, one of the around 40 coastal mineral sand deposits in Vietnam. The survey was carried out with the Raduet chambers made by Radosys Ltd—Hungary. The obtained results for 25 investigated points show that the measured values are not high in the residential houses and in case of the sand extraction site as well. At the titanium processing plant the measured values were higher than outside the facility (Radon: 18–55 Bq/m³ with average of 34 Bq/³ and Thoron 33–118 Bq/m³ with average of 58 Bq/m³) but still comparable to the average concentration of the world published by UNSCEAR. The typical outdoor levels of radon and thoron gas are each of the order of 10 Bq/m³. Although the radon concentrations were low in the zircon and titanium processing plants, the thoron concentrations in the houses for separating rutile and zircon were very high. At zircon processing factory, the thoron concentration could reach 2,931 Bq/m³ and the estimated annual effective dose would be 21.4 mSv/a. Intervention has to be taken in order to reduce the thoron level in this factory since the level of thoron and its progenies corresponding to an annual occupational effective dose is beyond the action level of 6 mSv/a.     

3D Study of the Morphology and Dynamics of Zeolite Nucleation

The principle aspects and constraints of the dynamics and kinetics of zeolite nucleation in hydrogel systems are analyzed on the basis of a model Na‐rich aluminosilicate system. A detailed time‐series EMT‐type zeolite crystallization study in the model hydrogel system was performed to elucidate the topological and temporal aspects of zeolite nucleation. A comprehensive set of analytical tools and methods was employed to analyze the gel evolution and complement the primary methods of transmission electron microscopy (TEM) and nuclear magnetic resonance (NMR) spectroscopy. TEM tomography reveals that the initial gel particles exhibit a core–shell structure. Zeolite nucleation is topologically limited to this shell structure and the kinetics of nucleation is controlled by the shell integrity. The induction period extends to the moment when the shell is consumed and the bulk solution can react with the core of the gel particles. These new findings, in particular the importance of the gel particle shell in zeolite nucleation, can be used to control the growth process and properties of zeolites formed in hydrogels.     

Synthesis and Transformation of 4-(1-Chloro-1-nitroethyl)-6,7-dimethoxy-2-methylquinazoline: Spectral Characterization and Anti-cancer Properties of some Novel Quinazoline Derivatives

An efficient and simple method has been reported for the synthesis of 4-(1-Chloro-1-nitroethyl)-6,7-dimethoxy-2-methylquinazoline ( 2 ) as a key compound for further transformation to other novel 6,7-dimethoxy-2-methyl-4-substituted quinazolines. The structure of the synthesized compounds was characterized by spectroscopic methods. The pathway of some unprecedented reactions was proposed. (E)-1-(6,7-dimethoxy-2-methylquinazolin-4-yl)-3-(4-nitrophenyl)prop-2-en-1-one (11) exhibits high in vitro cytotoxicity on three cell lines, Hepatocellular carcinoma (Hep-G2), Human lung carcinoma (LU-1), and Human breast carcinoma (MCF-7) with IC₅₀ of 2.1, 11.6 and 2.2 μM, respectively.