Enhanced Gas Separation Performance by Embedding Submicron Poly(ethylene glycol) Capsules into Polyetherimide Membrane

Recently, hollow filler as an emerging concept is attracting more attention in preparation of mixed matrix membranes(MMMs). Herein,poly(ethylene glycol) microcapsules(PMC) are synthesized via distillation precipitation polymerization and embedded into the polyetherimide(Ultem■1000) matrix to fabricate MMMs for CO₂ capture. The PMC exhibits a preferential hollow structure within the Ultem matrix to furnish highways within membrane, and thus achieve high gas permeability. Meanwhile, the favorable affinity of poly(ethylene glycol)(PEG)microcapsule with ether oxygen group(EO) towards CO₂ enhances the CO₂ solubility selectivity. Such integration of physical and chemical microenvironments in the as-designed PEG microcapsule affords highly enhanced CO₂ separation performance. Compared to pristine Ultem■1000, the membrane with 2.5 wt% PMC loading exhibits 310% increment in CO₂ permeability and 22% increment in CO₂/N₂ selectivity,which shows the promising prospects of designing PEG-containing microcapsules as the filler of MMMs for CO₂ capture.     

钡-聚乙二醇1000-四苯硼钠体系浊度法测定微量钡

在ＨＯＡｃ－ＮａＯＡｃ缓冲溶液中,Ｂａ＾２＋与聚乙二醇１０００及四苯硼钠反应生成在分子三元络 的型沉淀,据此建立了测定微量钡的浊度分析新体系。钡浓度在０～５．６μｇ．ｍｌ＾－１范围内符合经耳定律,检出限为０．０４μｇ．ｍｌ＾－１。方法具有灵敏、准确、简便、快捷,无须加入分散剂和体系稳定时间长等特点。用于岩石土壤标样中微量钡测定,结果满意。     

Synthesis and Crystal Structure of Tert-butyl 2-((phenylthio)-carbonyl)pyrrolidine-1-carboxylate

Tert-butyl 2-((phenylthio)carbonyl)pyrrolidine-1-carboxylate, was synthesized by using iso-butoxycarbonyl chloride (i-BuOCOCl) via mixed anhydride method. The obtained product was characterized spectroscopically and finally confirmed by X-ray diffraction studies. The title compound C₁₆ H₂₁ N O₃ S crystallizes in the triclinic space group P1 with the cell parameters a = 6.0250(7) Å, b = 8.2820(13) Å, c = 8.7700(14) Å, α = 102.352(4)°, β = 102.993(11)°, γ = 90.279(8)°, V = 415.89(10) Å³ and Z = 1. The proline ring in the structure is in a envelope conformation. The structure exhibits intermolecular hydrogen bonds of the type C–H...O.     

The use of thermal analysis techniques to obtain information relevant to thein-situ combustion process for enhanced oil recovery

Thein-situ combustion technique of enhanced oil recovery may be used for the recovery of heavy oil deposits. In order to predict when this process may be used computer-based simulators are being developed. The data required by these simulators are currently available from two sources: (i) combustion tubes; these are complex, expensive and time consuming to run; (ii) thermal analysis techniques; these are fast, small-scale and relatively inexpensive. Thermal analysis literature relevant to the process is reviewed and related thermal analysis studies being conducted at Salford University are described.     

Liquid chromatography on unmodified and modified spheron gels I. Nucleosides,bases and related compounds

Summary The ethylene glycol methacrylate gel Spheron and ion exchangers produced by the chemical modification of this gel (such as the cation exchanger Spheron S and anion exchanger Spheron DEAE) are compared with octadecylsilica as column packing materials for reversedphase chromatography of nucleic acid constituents and related compounds. The different separation selectivities of the individual materials can be utilized for the chromatographic separation of these compounds.     

The determination of disulphide species within physiological fluids

The clinical necessity for the analysis of oxidised thiol concentrations within physiological fluids has been clarified and current instrumental strategies identified. The various routes through which disulphide species can be analysed are summarised and the salient experimental aspects of each methodology compared and critically appraised.     

Liquid chromatography on unmodified and modified Spheron gels II. Barbiturates and sulfonamides

Summary The ethylene glycol methacrylate gel Spheron and ion-exchangers produced by the chemical modification of this gel (the cation exchanger Spheron S and the anion exchanger Spheron DEAE) can be used for reversedphase chromatography of barbiturates and sulfonamides. In addition to the hydrophobic effect, the unique selectivities of the functional groups of Spheron materials can be utilized for the chromatographic separation of these compounds, including those difficult to resolve on octadecyl silica.Principle author     

Silicaphosphine (Silphos): a filterable reagent for the conversion of alcohols and thiols to alkyl bromides and iodides

Silicaphosphine (Silphos), [P(Cl)_3−n(SiO₂)_n], as a new heterogeneous reagent is introduced. This reagent converts alcohols and thiols to their corresponding bromides and iodides in the presence of X₂ (X=Br, I) in refluxing CH₃CN in high to quantitative yields. Use of Silphos provides a highly practical method for the easy separation of the Silphos oxide byproduct by a simple filtration.     

Determination of trace amounts of gold in acid-attacked environmental samples by atomic absorption spectrometry with electrothermal atomization after preconcentration

A method for determination of trace amounts of gold in environmental samples (rocks, soils, sediments, and waters) by atomic absorption spectrometry with electrothermal atomization (ETAAS) after preconcentration using a chelating sorbent Spheron Thiol 1000 is described. The method accurately determines gold between 0.001 and several tens of grams per ton in samples having complex variations in mineralogy. Pulverized samples are roasted at 650°C to oxidize any sulfide and/or carbonaceous material. Samples are then subjected to a series of acid treatments to eliminate any silica matrix and to dissolve the sample. The Spheron Thiol 1000 is added to the sample solution, and then with sorbed gold is filtered out, washed, and ignited at 550°C. The residue is dissolved in aqua regia, evaporated, dissolved in distilled water, transferred to a volumetric flask, and analyzed by ETAAS.The limits of detection of gold, based on the 3 definition, were 0.5 ng g^–1 for 10-g samples (rocks, sediments, soils) and 0.05 ng mL^–1 for 1-L water samples. Precision of determination expressed by the relative standard deviation varied from 2.9% to 16.4%. The accuracy of the method is verified by analysis of certified reference materials. The obtained analytical results are in good agreement with attested values. The developed method was applied for gold determination in environmental samples affected by the acidification (acid mine drainage which is mainly a product of pyrite oxidation) from an open quartzite mine in the obov region situated NE of the city of Banská tiavnica (Slovakia).     

Underpotential Deposition and Stripping of Lead at Disorganized Monolayer‐Modified Gold Electrodes

Underpotential deposition (UPD) and stripping of Pb²⁺ at thiol‐based disorganized monolayer‐modified gold electrodes was studied by cyclic voltammetry (CV) and electrochemical quartz crystal microgravimetry (EQCM). Electrodes modified with mercaptoacetic acid or mercaptoethane sulfonic acid were studied. Due to the proximity of the potentials for the Pb UPD and thiol reductive desorption, achievement of a UPD‐stripping voltammetry methodology for determination of low concentrations of Pb²⁺ was not successful. However by comparison of the CV and EQCM data and consideration of the possible mass changes per mole electrons transferred in light of the other species present in solution, possible mechanisms are put forward for the deposition and stripping of Pb²⁺ at thiol‐modified electrodes.