超声波促进手性双酰基氧化膦的合成

以L-薄荷醇为原料,经3步反应制备得到中间体薄荷基二氯化膦.该中间体首先通过与超声波辐射制备的微米级钠粒反应形成薄荷基膦二钠盐,然后依次经过偶联及氧化反应合成了目标产物(-)-双(薄荷基甲酰基)薄荷基氧化膦(BMMPO),并经过1 H NMR、13 C NMR、31P NMR和元素分析进行了表征.     

Hydrothermal synthesis of peony-like CuO micro/nanostructures for high-performance lithium-ion battery anodes

The peony-like CuO micro/nanostructures were fabricated by a facile hydrothermal approach. The peonylike CuO micro/nanostructures about 3-5 μm in diameter were assembled by CuO nanoplates. These CuO nanoplates, as the building block, were self-assembled into multilayer structures under the action of ethidene diamine, and then grew into uniform peony-like CuO architecture. The novel peony-like CuO micro/nanostructures exhibit a high cycling stability and improved rate capability. The peony-like CuO micro/nanostructures electrodes show a high reversible capacity of 456 mAh/g after 200 cycles, much higher than that of the commercial CuO nanocrystals at a current 0.1 C. The excellent electrochemical performance of peony-like CuO micro/nanostructures might be ascribed to the unique assembly structure, which not only provide large electrode/electrolyte contact area to accelerate the lithiation reaction, but also the interval between the multilayer structures of CuO nanoplates electrode could provide enough interior space to accommodate the volume change during Li~+ insertion and de-insertion process.     

Triplet excitation dynamics of β-carotene studied in three solvents by ns flash photolysis spectroscopy

Upon anthracene-sensitizing, triplet excitation dynamics of β-carotene(β-Car) were studied in nhexane, in methanol, and in acetonitrile, respectively, by ns flash photolysis spectroscopy. In n-hexane,only the bleaching of the ground state absorption(GSB) and the excitation triplet(~3Car*) absorption were observed, and there were no cationic species detected. In both methanol and acetonitrile, similar excitation dynamics were observed, i.e.,~3Car* having a similar lifetime to that in n-hexane, and the immediate generation of the cation dehydrodimer(~#[Car]2~+) upon excitation following transformation into the radical cation Car*~+, since Car*~+ has much longer lifetime in acetonitrile than in methanol. The results prove that both solvent and carotenoid structure determine the triplet excitation mechanism.     

双酚F分子印迹聚合物的制备及其对水相中双酚F吸附性能的研究

以双酚F(4,4′-BPF)为模板分子,α-甲基丙烯酸(MAA)为功能单体,乙二醇二甲基丙烯酸酯(EGDMA)为交联剂,偶氮二异丁腈(AIBN)为引发剂,采用沉淀聚合法合成4,4′-BPF分子印迹聚合物(MIPs)。运用傅里叶红外(FT-IR)光谱对产物的结构进行表征,并对其吸附等温线、吸附动力学、吸附热力学及选择性识别性能进行研究。结果表明:MIPs对水相中4,4′-BPF具有特异性吸附,最大吸附容量为82.8 mg/g;Freundlich模型拟合吸附等温线的相关系数R2=0.995;热力学参数ΔG、ΔS、ΔH均小于0,表明此吸附过程是自发进行的、熵减的、放热的。     

超声提取–离子色谱法测定土壤易溶盐中的氯离子和硫酸根离子

采用超声提取的方式,以离子色谱法测定土壤易溶盐中的氯离子和硫酸根离子。对实验条件进行了优化,色谱柱为NJ–SA–4A柱(250 mm×2 mm),保护柱为SI–92G柱(50 mm×4 mm),淋洗液为1.8 mmol/L Na_2CO_3–1.7mmol/L NaHCO_3,流量为1.0 m L/min;在40℃下,对土壤样品提取10 min。Cl~–和SO_4~(2–)在检测范围内均线性良好,线性相关系数为0.999 8,加标回收率分别为95.0%~99.0%,96.0%~101.0%,测定结果的相对标准偏差分别为1.4%,1.0%(n=4)。与传统的方法相比,该法试剂用量少,操作简单,可用于土壤易溶盐样品的测定。     

用单颗粒气溶胶质谱研究海宁市秋、冬季PM_(2.5)化学组成及来源

对海宁市区PM_(2.5)来源进行分析,分别于2016年11月11日~24日以及2016年12月13日~21日期间,使用单颗粒气溶胶质谱仪(SPAMS)在海宁市环境保护监测站点位进行了为期14天和8天的定点监测,分别代表了秋季和冬季的监测结果。结果表明,监测期间海宁市总体空气质量较好,优、良天气占比为75.8%。海宁市首要污染物为机动车尾气源,燃煤源次之,工业源排在第三位。整体来看,监测期间PM_(2.5)质量浓度的升高大多伴随着燃煤及机动车尾气占比的同步升高。秋、冬季的重度污染过程与燃煤源和机动车尾气源的升高有关,其中秋季的燃煤源贡献高峰可能与监测点位西北方向的气团传输有关。     

A novel method to prepare microcellular poly(vinyl alcohol) foam based on thermal processing and supercritical fluid

Combining the thermal processing and supercritical fluid technology develops a novel preparation method of microcellular poly(vinyl alcohol) (PVA). Water, as the plasticizer in system, can form the hydrogen bonding with pendant hydroxyl of PVA and weaken its strong intermolecular and intramolecular forces to realize the thermal processing. Supercritical carbon dioxide (sc‐CO₂) can easily dissolve into water‐plasticized PVA (WPVA) because of the destruction of crystal region caused by water, and the enhanced sc‐CO₂ solubility can greatly improve the foamability of WPVA. The porous structure generates through the saturation of sc‐CO₂ in WPVA sample and followed by pressure drop‐induced phase separation. The foaming behavior of WPVA was studied as a function of saturation pressure, foaming temperature, and saturation time. The cell density, cell size, and distribution of the obtained foam can be controlled by tuning processing conditions. The results revealed that the cell size decreased, and its distribution narrowed with saturation pressure increasing, or decrease of foaming temperature. But excessively increasing the saturation time generated a negative effect on the foaming behavior owing to the deteriorated plasticization effect resulted from the loss of water. Copyright © 2016 John Wiley & Sons, Ltd.     

Ionic liquid functionalized graphene oxide for enhancement of styrene‐butadiene rubber nanocomposites

Ionic liquid 1‐allyl‐3‐methyl‐imidazolium chloride (AMICl) is used to fine‐tune the surface properties of graphene oxide (GO) sheets for fabricating ionic liquid functionalized GO (GO‐IL)/styrene‐butadiene rubber (SBR) nanocomposites. The morphology and structure of GO‐IL are characterized using atomic force microscope, X‐ray diffraction, differential scanning calorimetry, X‐ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, UV‐vis spectra and Raman spectra. The interaction between GO and AMICl molecules as well as the effects of GO‐IL on the mechanical properties, thermal conductivity and solvent resistance of SBR are thoroughly studied. It is found that AMICl molecules can interact with GO via the combination of hydrogen bond and cation–π interaction. GO‐IL can be well‐dispersed in the SBR matrix, as confirmed by X‐ray diffraction and scanning electron microscope. Therefore, the SBR nanocomposites incorporating GO‐IL exhibit greatly enhanced performance. The tensile strength, tear strength, thermal conductivity and solvent resistance of GO‐IL/SBR nanocomposite with 5 parts per hundred rubber GO‐IL are increased by 505, 362, 34 and 31%, respectively, compared with neat SBR. This method provides a new insight into the fabrication of multifunctional GO‐based rubber composites. Copyright © 2016 John Wiley & Sons, Ltd.     

The Effect of Intermolecular Hydrogen Bonding on the Polyaniline Water Complex

The polyaniline water hydrogen-bonded complex was studied by first-principles calculation. The density functional theory method was used to calculate the structure characters, natural bond orbital charge distribution, infrared spectra and the frontier molecular orbital. Results showed that the H–O···H–N and C–N···H–O type intermolecular hydrogen bonds were formed. The bonds involved in the intermolecular H-bond were all influenced by the hydrogen bonding interaction. During the hydrogen bond formation, the polymer chains in the complexes were all charged, which can be an important factor contributing to the increase of electrical conductivity. The N1–H vibration was strongly influenced, and the locations as well as the intensities of N1–H absorption bands were all changed in the complexes. In the orbital transition of HOMO to LUMO, the electron density transferred from benzenoid ring to quinoid ring.     

四氯化碳液相催化加氢制氯仿多元金属催化剂的制备及其催化性能

以贵金属M(=Pd,Pt)为主要活性成分,掺加过渡金属Fe和Ni作为助剂,采取浸渍和氢气还原法制备了椰壳活性炭(ACcs)负载的单元金属(M/ACcs)、二元金属(M-Ni/ACcs、M-Fe/ACcs)和三元金属(M-Ni-Fe/ACcs)系列催化剂;通过CC_l4液相催化加氢制氯仿反应考察了这些催化剂的催化活性和选择性。结果表明,Pd基催化剂的催化活性明显高于Pt基催化剂,但后者对氯仿的选择性优于前者;在前5 h加氢反应时段,两系列催化剂的活性顺序为:Pd-Ni-Fe/ACcsPd-Fe/ACcsPd/ACcsPd-Ni/ACcs和Pt/ACcs≈Pt-Fe/ACcsPt-Ni/ACcsPt-Ni-Fe/ACcs;总体上,引入Fe对于催化性能的改善效果要优于Ni,Ni的单独引入则会不同程度地降低催化活性。综合考量成本、活性和选择性等因素,优选Pd-Ni-Fe/ACcs作为催化剂,在393 K下反应5 h,可实现CC_l497.6%的转化率以及接近100%氯仿的选择性。