Bifunctional Boron Phosphate as an Efficient Catalyst for Epoxide Activation to Synthesize Cyclic Carbonates with CO2

Development of inexpensive, easily prepared, non‐toxic, and efficient catalysts for the cycloaddition of CO₂ with epoxides to synthesize five‐membered cyclic carbonates is a very attractive topic in the field of CO₂ transformation. In this work, we conducted the first work on the cycloaddition of CO₂ with epoxides to produce cyclic carbonates catalyzed by a binary catalyst system consisting of KI and boron phosphate (BPO₄), which are both inexpensive and non‐toxic, and various corresponding cyclic carbonates could be produced with high yields (93–99 %) at 110 °C with a CO₂ pressure of 4 MPa under solvent‐free conditions. In the BPO₄/KI catalyst system, BPO₄, a Brønsted and Lewis acid hybrid, played the role of activating the epoxy ring through the formation of hydrogen bonds with Brønsted acidic sites and the interaction with Lewis acidic sites simultaneously, and thus enhanced the activity of KI for the cycloaddition of CO₂ with epoxides significantly. Additionally, the activity of the BPO₄/KI catalyst system showed no noticeable decrease after being reused five times, indicating that the BPO₄ was stable under the reaction conditions.     

Carbon K‐edge spectra of carbonate minerals

Carbon K‐edge X‐ray spectroscopy has been applied to the study of a wide range of organic samples, from polymers and coals to interstellar dust particles. Identification of carbonaceous materials within these samples is accomplished by the pattern of resonances in the 280–320 eV energy region. Carbonate minerals are often encountered in the study of natural samples, and have been identified by a distinctive resonance at 290.3 eV. Here C K‐edge and Ca L‐edge spectra from a range of carbonate minerals are presented. Although all carbonates exhibit a sharp 290 eV resonance, both the precise position of this resonance and the positions of other resonances vary among minerals. The relative strengths of the different carbonate resonances also vary with crystal orientation to the linearly polarized X‐ray beam. Intriguingly, several carbonate minerals also exhibit a strong 288.6 eV resonance, consistent with the position of a carbonyl resonance rather than carbonate. Calcite and aragonite, although indistinguishable spectrally at the C K‐edge, exhibited significantly different spectra at the Ca L‐edge. The distinctive spectral fingerprints of carbonates provide an identification tool, allowing for the examination of such processes as carbon sequestration in minerals, Mn substitution in marine calcium carbonates (dolomitization) and serpentinization of basalts.     

Synthesis of 5-[(2-hydroxynaphthalen-1-yl)diazenyl]isophthalic acid and its application to electrocatalytic oxidation and determination of adrenaline,paracetamol, and tryptophan

In this study,Au nanoparticles/poly 5-[(2-hydroxynaphthalen-l-yl)diazenyl]isophthalic acid film modified glassy carbon electrode(AuNPs/poly(NDI)/GCE) has shown excellent electrocatalytic activity toward the oxidation of adrenaline(ADR),paracetamol(PAC),and tryptophan(Trp).The bare glassy carbon electrode(GCE) fails to separate the oxidation peak potentials of these molecules,while the poly(NDI) film modified electrode can resolve them.Electrochemical impedance spectroscopy(EIS)indicates that the charge transfer resistance of the bare electrode decreases as 5-[(2-hydroxynaphthalen-l-yl)diazenyl]isophthalic acid is electropolymerized on the bare electrode.Furthermore,EIS exhibits enhancement of electron transfer kinetics between analytes and the electrode after electrodeposition of Au nanoparticles.Differential pulse voltammetry results show that the electrocatalytic current increases linearly in the ranges of 0.01-680.0 μmol L~1 for ADR,0.05-498.0 μmol L~1 for PAC,and 3.0-632.0 μmol L~1 for Trp;with detection limits(S/N = 3) of 0.009 μmol L~1,0.005 μmol L~1,and 0.09 μmol L~1 for ADR,PAC,and Trp,respectively.The proposed method has been successfully applied for simultaneous determination of ADR,PAC,and Trp in biological samples.     

A degradable atom transfer radical polymerization inimer: Synthesis,polymerization, and cleavage of the resulting polymer products

A novel degradable inimer for atom transfer radical polymerization (ATRP), 2‐(6‐(2‐((2‐bromo‐2‐methylpropanoyl)oxy)ethyl)pyridin‐2‐yl)ethyl methacrylate (PyDEBrMΑ), was synthesized by the two‐step esterification of 2,6‐pyridinediethanol, first with α‐bromoisobutyryl bromide in order to introduce the initiator moiety, and then with methacryloyl chloride in order to introduce the monomer moiety. PyDEBrMA was subsequently used to initiate the self‐condensing ATRP of methyl methacrylate (MMA) to obtain a hyperbranched MMA homopolymer which could be cleaved at the PyDEBrMA residue either by treatment under mildly alkaline hydrolysis conditions (sodium deuteroxide in d₆‐DMSO at room temperature) or thermolysis at 150 °C. The lability of the PyDEBrMA residue arises from the presence in its structure of two 2‐(pyridin‐2‐yl)ethyl ester moieties. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2831–2839     

生物质与烟煤混合灰熔融特性影响因素的研究

为探究气氛、混合比及残炭含量对生物质与煤混合灰熔融特性的影响,将松木屑灰与乌海烟煤灰按不同质量比混合,采用智能灰熔点仪测定各混合灰样在不同气氛下的灰熔融温度,X射线衍射仪从矿物质演变角度分析混合灰熔融温度变化的原因。结果表明,由于铁尖晶石和铁橄榄石的生成,使混合灰的熔融温度在弱还原性气氛下比氧化性气氛下低,且差值的大小与混合灰中Fe含量有关;随松木屑灰含量的增加,钙铝黄长石、镁黄长石、白榴石等低温共熔物的生成量增加,使混合灰的熔融温度降低;此外,由于Fe-C共熔体(Fe_xC_y)的生成、灰锥局部还原性气氛及残炭的"骨架"作用,使混合灰的熔融温度随煤灰中残炭含量的增加呈现先升高后降低再升高的趋势。     

Electrochemical sensors of heavy metals using novel polymer-modified glassy carbon electrodes

Electroanalytical determination of heavy metals using stripping voltammetry is commonly employed and has many advantages over other methods. The sensitivity of the technique is greatly improved by employing different modified electrodes. Seven novel polymer-modified glassy carbon electrodes have been developed in this investigation for the trace analysis of heavy metals such as zinc, cadmium, lead, arsenic, and copper in formulated samples of waters by square wave stripping voltammetry. Very good responses have been observed for all the metals, while all the modified electrodes employed. The poly(3,4-ethylenedioxythiophene)-modified electrode has resulted in very low limit of detection (LOD) value. Comparison is made between literature results of LOD and the results obtained in this study. An independent atomic absorption spectroscopic analysis of the industrial wastewater sample was carried out and the results compared. The suitability of the method for practical application was ascertained by applying the procedure for the wastewater from a plating industry.