Synthesis of Homoallylic Alcohols From Ketones in Water

Homoallylic alcohols have been prepared in good yields by allylation of ketones with allyl bromide in the presence of stannous chloride dihydrate, zinc iodide, and ammonium chloride in water.     

One‐Pot Wittig Reactions in Aqueous Media: A Rapid and Environmentally Benign Synthesis of α,β‐Unsaturated Carboxylic Esters and Nitriles

One‐pot Wittig reactions of ethyl bromoacetate and bromoacetonitrile with aldehydes in the presence of PPh₃ and LiOH in water were investigated. Most of the olefination reactions completed within 5–120 min in refluxing water containing 1.2 M LiCl to afford the olefin products in 71–97% yields with 100:0–55:45 ratios of E:Z isomers.     

Diammonium Hydrogen Phosphate: An Efficient and Versatile Catalyst for the One‐Pot Synthesis of Tetrahydrobenzo[b]pyran Derivatives in Aqueous Media

Diammonium hydrogen phosphate was used as a mild, efficient, neutral, and cheap catalyst for the synthesis of various 4H‐benzo[b]pyran derivatives via a one‐pot, three‐component condensation of aromatic aldehydes, active methylene compounds, and dimedone in aqueous media.     

Efficient and Industrially Viable Synthesis of Donepezil

An efficient, economically viable process has been developed for large‐scale preparation of donepezil HCl (1), an anti‐Alzheimer's agent. The process involves the condensation of 5,6‐dimethoxy‐1‐indanone (3) and 1‐benzyl‐4‐piperidinecarboxaldehyde (4) in the presence of alkalimetal carbonates at elevated temperature to yield 1‐benzyl‐4‐[(5,6‐dimethoxy‐1‐indanone)‐2‐yidenyl] methyl piperidine (2), the key intermediate in the synthesis of donepezil. Hydrogenation of 2 yields donepezil.     

缺陷金属有机骨架的制备及其去除水中污染物的研究进展

在避免母体结构坍塌的前提下,通过缺陷工程对金属有机骨架(MOFs)进行处理可有效提升其去除水体污染物的性能。目前,通过调整合成条件(温度、金属/配体比例等)、添加调制剂、热处理和金属节点取代等方式可制备缺陷MOFs。粉末X射线衍射(PXRD)、比表面积分析、热重-差热分析(TGA-DSC)、电子顺磁共振(EPR)、X射线光电子能谱(XPS)、高分辨率透射电子显微镜(HR-TEM)、球差校正透射电镜(AC-TEM)和X射线吸收光谱(XAS)表征技术可证实MOFs中缺陷的特征。相比原始MOFs,从光催化等高级氧化的角度来看,构造缺陷型MOFs可促进电子转移、减小带隙以提升其高级氧化降解去除污染物的性能。此外,缺陷型MOFs还可为污染物提供更多吸附位点,进一步提升吸附剂的吸附容量和吸附速率。本文系统总结缺陷MOFs的制备方法、现有常见表征技术及其在水处理领域中的应用。同时,本文还根据缺陷MOFs用于去除水中污染物的研究现状对其今后发展予以展望。     

纯水中检测汞离子与银离子的菲啰啉类荧光探针

合成了菲啰啉类化合物探针1,并通过核磁共振波谱(NMR)、质谱(MS)、红外光谱(IR)对其结构进行了表征。利用荧光发射光谱考察了探针1对Hg~(2+)及Ag~+的识别性能。结果表明,探针1在纯水介质中以荧光猝灭的方式识别Hg~(2+)和Ag~+,其结合比分别为1∶1和2∶1,检测的线性范围分别为9.0×10~(-7)～1.1×10~(-5)和8.0×10~(-7)～7.0×10~(-6) mol/L,相关系数(r~2)均大于0.99,检出限均低至10~(-8)mol/L。根据探针1识别前后荧光强度的剧烈变化,建立了裸眼检测Hg~(2+)和Ag~+的可视化分析方法。通过等温量热滴定与~1H NMR滴定考察了识别过程的热力学参数和作用机理。该研究对生物体及环境领域中Hg~(2+)和Ag~+的实时监测具有潜在的应用价值。     

Activity coefficients for NaBr in aqueous ternary solutions with sodium propionate and butyrate from EMF measurements

The activity coefficients of NaBr in the NaBr–NaPropionate–H₂O and NaBr–NaButyrate–H₂O systems were determined from EMF measurements at constant total ionic strength of 0.1 0.5 1.0 1.5 2.0 and 2.5 mol-kg^–1 and at 25° C. The activity coefficients were fitted using Scatchard, Pitzer and Lim equations. Finally the excess Gibbs free energy of these mixtures were also calculated.     

Thermodynamic properties of aqueous mixtures of LiCl and Li2SO4 at different temperatures

Emf measurements were made on the cell without liquid junction: Li?ISE LiCl(m₁), Li₂SO₄(m₂) Ag/AgCl. The performances of the electrode pairs constructed in our laboratory were tested and exhibited near-Nernstian behavior. The mean activity coefficients of LiCl for the system Li⁺?Cl^??SO ₄ ^2? ?H₂O have been investigated by the emf values at temperatures of 0, 15, 35°C and constant total ionic strengths of 0.05, 0.1, 0.5, 1.0, 2.0, 3.0 and 5.0 mol·kg^?1. The activity coefficients decrease with increasing temperature and the ionic strength fraction of Li₂SO₄ in the mixtures. The thermodynamic properties are interpreted by use of Harned's empirical equations and Pitzer's ion interaction approach including the contribution of higher order electrostatic terms. The experimental results obey Harned's rule and are described by using Pitzer equations satisfactorily. The activity coefficients of Li₂SO₄, the osmotic coefficients and the excess free energies of mixing for the system in the experimental temperature range were reported.     

Polymer Brushes via ATRP: Role of Activator and Deactivator in the Surface‐Initiated ATRP of Styrene on Planar Substrates

The role of activator and deactivator species in the surface‐initiated atom‐transfer radical polymerization of styrene using CuBr/CuBr₂/pentamethyldiethylenetriamine as a model system is described. The influence of initially added deactivator with respect to the degree of controlling the layer growth and thickness is studied. Variation of the activator concentration results in changes of the kinetics as well as brush thicknesses consistent with the well‐known rate laws of ATRP.     

Solubilization of methane,ethane, propane andn-butane in aqueous solutions of sodium dodecylsulfate

The solubilities of methane, ethane, propane, and n-butane were measured in aqueous solutions of sodium dodecylsulfate (NaDS) (0–0.1M) from 15 to 27°C. From these measurements the standard Gibbs energies, entropies, and enthalpies for the process of transferring the solute molecules from the gaseous phase into the solutions were calculated. An approximate relationship was found relating the volume fraction of the micelles to NaDS concentration.