Quinazoline Antifolate Thymidylate Synthase Inhibitors: Replacement of Glutamic Acid by Aminophosphonic Acids

The synthesis of six analogues of the potent thymidylate synthase (TS) inhibitor N -[4-[ N -[(3,4-dihydro-2-methyl-4-oxo-6-quinazolinoyl)-methyl]- N -prop-2-ynylamino]benzoyl]- L -glutamic acid 2 is described in which the glutamic acid residue has been replaced by DL -aminophosphonic acids. New antifolates were tested as inhibitors of TS isolated from mouse L1210 leukemic cells as well as inhibitors of growth mouse leukemic L5178Y cells. In general these modifications result in compounds that are considerably less potent than 2 as TS inhibitors with K i 's 0.17-1.10 w M. Very poor solubility in water limited their proper assay of growth cells inhibition.     

Using Prussian blue analogue nanoparticles confined into ordered mesoporous silica monoliths as precursors of oxides

Powdered Prussian blue analogues (PBAs) and PBAs confined in ordered mesoporous silica monoliths were used as oxide precursors through thermal treatment under an oxidizing atmosphere. The study focuses on the transformation of the alkali cation-free CoCo PBA of chemical formula K_0.1Co^II₄[Co^III(CN)₆]_2.7·20 H₂O. The compounds were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), IR spectroscopy and small-angle X-ray scattering (SAXS), and the magnetic properties of the calcined samples were investigated. In both cases, powdered and confined PBAs, the coordination polymers are transformed into well-crystallized Co₃O₄ spinel oxide. In the case of the confined PBA, isolated Co₃O₄ single crystals confined within the ordered mesoporosity of the monoliths were evidenced by HRTEM. A preliminary study shows an effect of particle size and confinement on the magnetic properties of the confined oxide particles.     

Sn-Al-β分子筛酸性在葡萄糖转化反应中作用的固体NMR研究

制备了一系列具有不同酸性质的β分子筛催化剂, 通过固体核磁共振(NMR)探针分子技术对其酸性质进行了表征, 并考察了其催化葡萄糖转化为乙酰丙酸甲酯的性能. 吸附三甲基磷的³¹P NMR实验结果表明, 含有骨架Sn以及Al原子的Sn-Al-β催化剂同时具有Br?nsted与Lewis酸性. 通过2-¹³C-丙酮探针分子区分出 3种酸强度的Br?nsted酸位, 其中一种酸强度接近“超强酸”, 可能是由于空间邻近的Br?nsted酸位和Lewis酸位发生协同作用产生的. 葡萄糖转化为乙酰丙酸甲酯的催化反应结果表明, 相比于分别只含有Lewis酸位和Br?nsted酸位的Sn-β和Al-β样品以及两者的物理混合样品, Sn-Al-β分子筛催化剂具有高催化活性与产物选择性, 这主要是由于Br?nsted酸位和Lewis酸位的协同作用产生了强Br?nsted酸位, 这种强Br?nsted酸位进一步导致了更高的催化活性.     

Esterification of Oleic Acid to Produce Biodiesel over 12-Tungstophosphoric Acid Anchored Two-dimensional Zeolite

Biodiesel has emerged as a non-toxic, biodegradable, and renewable fuel substitute that can be readily produced via the esterification reaction of free fatty acids. The present work explores the potential of 12-tungstophosphoric acid(TPA) anchored two-dimensional(2D) ITQ-2 zeolite(TPA/ITQ-2) as heterogeneous acid catalysts for biodiesel production. TPA/ITQ-2 material was prepared by swelling, delamination, and subsequent wetness incipient impregnation approach. The prepared catalysts were comprehensively characterized by powder X-ray diffraction, N₂ adsorption/desorption, temperature-programmed desorption of ammonia, flou-rier transform infrared spectroscopy, and transmission electron microscopy. The catalytic activity of TPA/ITQ-2 for biodiesel production was evaluated by the esterification reaction of oleate acid with methanol. Process parameters, such as reactant molar ratio and TPA loading were optimized. Due to the superior mass transfer and adequate stable acid sites, 2D TPA/ITQ-2 showed a higher catalytic activity and a better recyclable stability than the 3D and layered TPA/zeolites. This work will provide new opportunities for the design of 2D zeolite-based acid catalysts for biodiesel production.     

Voltammetric Analysis of Oxymetazoline Hydrochloride at Zeolite – Modified Carbon Paste Electrode in Micellar Medium

Simple, sensitive, accurate and inexpensive differential pulse (DPV) and square wave (SWV) voltammetric methods utilizing zeolite modified carbon paste electrode (ZMCPE) were developed for the determination of Oxymetazoline hydrochloride (OXM) in nasal drops. Various experimental parameters were optimized using cyclic voltammetry (CV). Calibration curves were linear over the concentration ranges 9.8×10⁻⁸–3.6×10⁻⁶ M and 9.8×10⁻⁶–9×10⁻⁵ M for DPV and SWV, respectively. The DPV method showed a limit of detection (LOD) of 1.04×10⁻⁷ M. The method was applied for the determination of OXM in pharmaceutical formulation with an average recovery of 101.18 % (%RSD=0.41, n=9).     

分子筛膜反应器的研究进展

分子筛膜具有规整的微孔结构(<1 nm), 耐高温高压、 抗有机溶剂, 在液相和气相小分子分离中受到广泛关注. 分子筛膜可以与催化反应耦合于一体构成膜反应器, 使反应过程与组分分离同时进行, 促进反应平衡移动, 达到反应强化的效果. 本文概述了近十年不同类型分子筛膜反应器在催化反应中的应用研究进展, 并对分子筛膜反应器未来的发展趋势进行了展望.     

Zeolites are no longer a challenge: Atomic resolution data by Aberration-corrected STEM

Transmission electron microscopy is undoubtedly an indispensable tool for materials characterization, which can currently reach sub-angstrom resolution down to the elemental building blocks of matter, isolated single atoms of most elements. In addition to the phenomenal image resolution, if the material is strong enough, it can be accompanied with chemical information, converting electron microscopy into a unique method for the analysis of a great variety of materials. Unfortunately, extracting all this valuable information is not simple as most materials in one way or another are affected by the strong and localized electron beam. Radiolysis is one kind of reaction between electrons and matter than can cause irreversible structural transformations in our materials. This effect is the predominant factor in zeolites, zeotypes and the majority of molecular sieves. In the present work some results, taken at high voltage (300 kV) and minimizing the exposure to the beam, are presented proving the feasibility of the technique to obtain unprecedented atomic resolution information of different zeolites and microporous solids.     

具有抗生物污染活性的分子筛膜用于高效油水分离

The development of the global economy has been accompanied by frequent oil spills caused by accidental leaks and industrial manufacturing, which have seriously threatened the aquatic environment and human health. Traditional methods for the treatment of oily wastewater include centrifugation, skimming, flotation, oil-absorbing technology, etc., which are limited by low separation efficiency as well as secondary pollution during the post-processing of oil absorption materials. Recently, separation technologies utilizing the special wettabilities of filtration membranes have been developed to enrich and recycle oils from wastewater. Among these, the fabrication of superhydrophilic/underwater superhydrophobic membranes have attracted intensive research interest, which can selectively allow the passage of water through the membrane while blocking the oils. However, microorganisms are more likely to breed on these hydrophilic surfaces, eventually leading to the blockage of the membranes. In this study, ZSM-5 zeolite crystals (MFI topological structure) were coated onto the stainless-steel meshes by means of seeding and secondary hydrothermal growth. Then, 70% of the total Na⁺ ions in the zeolite channels were substituted by Ag⁺ ions via an ion exchange process. The resultant membranes (Ag@ZCMFs) were superamphiphilic in air, with both water contact angle and oil contact angle of approximately 0°. However, they became superoleophobic when immersed in water, and the underwater oil contact angle reached 151.27° ± 4.34°. In terms of special wettability, Ag@ZCMF achieved efficient separation for various oil-water mixtures with separation efficiencies above 99%. The water flux and intrusion pressure of Ag@ZCMF depended on the diameter of pinholes in the membrane, which could be modulated by altering the time of secondary hydrothermal growth. For instance, the average diameter of pinholes in Ag@ZCMF with optimum secondary growth time of 14 h (Ag@ZCMF-14) reached approximately 21 μm, giving rise to the water flux and intrusion pressure of 54720 L·m^-2·h^-1 and 4357 Pa, respectively. The anti-corrosion test and rubbing test confirmed the high chemical and mechanical stability of Ag@ZCMF-14, respectively. The separation efficiency of Ag@ZCMF-14 remained stable during ten purification-regeneration cycles, and no obvious attenuation was observed, proving the high separation stability of Ag@ZCMF-14. Furthermore, the loaded Ag⁺ ions afforded the membrane excellent anti-biofouling activity, which could effectively inhibit the growth of both alga and bacteria in the operating environment, thus preventing membrane blockage during the oil-water separation process. In particular, the bacteriostatic rate of Ag@ZCMF-14 to Escherichia coli reached to 99.6%. These results demonstrate that Ag@ZCMFs with anti-biofouling activity has promising potential future applications in the removal of oil slicks from oily wastewater.     

ZIF‐8‐Nanocrystalline Zirconosilicate Integrated Porous Material for the Activation and Utilization of CO2 in Insertion Reactions

The conversion of CO₂ to useful chemicals, especially to atom economical products, is the best approach to utilize an excess of CO₂ present in the atmosphere. In this study, a metal‐organic framework (ZIF‐8) is integrated with nanocrystalline zirconosilicate zeolite to develop an integrated porous catalyst for CO₂ insertion reactions. The catalyst exhibits excellent activity for the CO₂ insertion reaction of epoxide to produce cyclic carbonate in neat condition without the addition of any co‐catalyst. The catalyst is stable and recyclable during the cyclic carbonate synthesis. Further, the catalyst also exhibits very good activity in another CO₂ insertion reaction to produce quinazoline‐2,4(1H, 3H)‐dione.