Molten salt as ultrastrong polar solvent enables the most straightforward pyrolysis towards highly efficient and stable single-atom electrocatalyst

Currently,pyrolysis as the most widely used method still has some key issues not well resolved for synthesis of carbon-supported single-atom catalysts(C-SACs),e.g.,the sintering of metal atoms at high temperature as well as the high cost and complicated preparations of precursors.In this report,molten salts are demonstrated to be marvellous medium for preparation of C-SACs by pyrolysis of small molecular precursors(ionic liquid).The ultrastrong polarity on one hand establishes robust interaction with precursor and enables better carbonization,resulting in largely enhanced yield.On the other hand,the aggregation of metal atoms is effectively refrained while no nanoparticle or cluster is formed.By this strategy,a C-SAC with atomically dispersed Fe-N_(4) sites and a high specific area over 2000 m^(2) g^(-1) is obtained,which illustrates high ORR activity in both acid and alkaline media.Moreover,this SAC exhibits superior methanol tolerance and stability after acid soaking at 85℃ for 48 h.It is believed that the molten-salts-assisted pyrolysis can be developed into a routine strategy as it not only can largely simply the synthesis of C-SACs,but also can be extended to prepare other types of SACs.

Enhancing lead-free photovoltaic performance:Minimizing buried surface voids in tin perovskite films through weakly polar solvent pre-treatment strategy

Buried interfacial voids have always been a notorious phenomenon observed in the fabrication of lead perovskite films. The existence of interfacial voids at the buried interface will capture the carrier, suppress carrier transport efficiencies, and affect the stability of photovoltaic devices. However, the impact of these buried interfacial voids on tin perovskites, a promising avenue for advancing lead-free photovoltaics, has been largely overlooked. Here, we utilize an innovative weakly polar solvent pretreatment strategy(WPSPS) to mitigate buried interfacial voids of tin perovskites. Our investigation reveals the presence of numerous voids in tin perovskites during annealing, attributed to trapped dimethyl sulfoxide(DMSO) used in film formation. The WPSPS method facilitates accelerated DMSO evaporation, effectively reducing residual DMSO. Interestingly, the WPSPS shifts the energy level of PEDOT:PSS downward, making it more aligned with the perovskite. This alignment enhances the efficiency of charge carrier transport. As the result, tin perovskite film quality is significantly improved,achieving a maximum power conversion efficiency approaching 12% with only an 8.3% efficiency loss after 1700 h of stability tests, which compares well with the state-of-the-art stability of tin-based perovskite solar cells.

Non-polar Solvent Microwave-Assisted Extraction of Volatile Constituents from Dried Zingiber Officinale Rosc.

A new method, non-polar solvent microwave-assisted extraction （NPSMAE）, was applied to the extraction of essential oil from Zingiber officinale Rosc. in closed-vessel system. By adding microwave absorption mediumcarbonyl iron powders （CIP） into extraction system, the essential oil was extracted by the non-polar solvent （ether） which can be heated by CIP. The constituents of essential oil obtained by NPSMAE were comparable with those obtained by hydrodistillation （HD） by GC-MS analysis, which indicates that NPSMAE is a feasible way to extract essential oil from dried plant materials. The NPSMAE took much less extraction time （5 min） than HD （180 min）, and its extraction efficiency was much higher than that of conventional polar solvent microwave-assisted extraction （PSMAE） and mixed solvent microwave-assisted extraction （MSMAE）. It can be a good alternative for the extraction of volatile constituents from dried plant samples.

Effects of Hydrogen-bonding Interaction and Polarity on Emission Spectrum of Naphthalene-Triethylamine in Mixed Solvent

The effects of the protic and aprotic polar solvents on the emission spectrum of the naphthalene-triethyl-amine system in THF were studied under conditions of steady-state illumination. The fluorescence spectrum of the naphthalene-triethylamine system consists of two emission bands, the fluorescence band of naphthalene(band A, 329 nm) and the emission band of the exciplex(band B, 468 nm). The intensities of both the emission bands decrease with increasing the solvent polarity. The intensity of band B also decreases due to the hydrogen-bonding interaction between triethylamine and protic solvent, while that of band A increases. It is thus suggested that the quenching of naphthalene fluorescence by triethylamine in THF occurs through the charge transfer and electron transfer reactions. The spectral changes upon the increase of solvent polarity can be explained by the dependences of the equilibrium constant between exciplex and ion-pair and the rate constant for the electron transfer reaction from triethylamine to the excited naphthalene on the relative permittivity of solvent. It is shown that the formation of intermolecular hydrogen-bonding between triethylamine and protic solvent suppresses the quenching reaction by the decrease in free amine. Acetonitrile has only a polar effect and trichloroacetic acid only a hydrogen-bonding(or protonation) effect, while alcohols have both the effects. The effects of alcohols could be separated into the effects of solvent polarity and intermolecular hydrogen-bonding interaction quantitatively.

Effects of Polar Organic Solvent on Separation of Y(edta)^-/Nd(edta)^- Complexes on Polyacrylic Anion Exchangers

The use of polar organic solvents for the separations of rare earth elements (Ⅲ) is effective especially for their extensive separations despite the solubility limitations. The study shows that polyacrylate anion exchangers, particularly the weakly basic, gel anion exchanger Amberlite IRA 68, can be applied to the separation of rare earth complexes with EDTA in H_2O-methanol and H_2O-ethanol systems. In most cases the determined distribution coefficients of Ln^(3+) complexes with EDTA in mixed media like water-methanol on polyacrylate anion exchangers are larger than those in pure water (media.)

Effect of Solvent Polarity on Excited-State Double Proton Transfer Process of 1,5-Dihydroxyanthraquinone

The excited-state double proton transfer(ESDPT)properties of 1,5-dihydroxyanthraquinone(1,5-DHAQ)in various solvents were investigated using femtosecond transient absorption spectroscopy and the DFT/TDDFT method.The steady-state fluorescence spectra in toluene,tetrahydrofuran(THF)and acetonitrile(ACN)solvents presented that the solvent polarity has an effect on the position of the ESDPT fluorescence emission peak for the 1,5-DHAQ system.Transient absorption spectra show that the increasing polarity of the solvent accelerates the rate of excited state dynamics.Calculated potential energy curves analysis further verified the experimental results.The ESDPT barrier decreases gradually with the increase of solvent polarity from toluene,THF to ACN solvent.It is convinced that the increase of solvent polarity can promote the occurrence of the ESDPT dynamic processes for the 1,5-DHAQ system.This work clarifies the mechanism of the influence of solvent polarity on the ESDPT process of 1,5-DHAQ,which provides novel ideas for design and synthesis of new hydroxyanthraquinone derivatives.

Propylene Polymerization Catalyzed by Bis(R_3-indenyl) Zirconium Bichloride/Aluminoxane──Synthesis of Metallocenes and Influence ofSolvent Polarity on Polymerization

Three unbridged metallocenes, bis(2,4,7-Me3-indenyl)zirconium dichloride(1) , bis(2-Me-4, 7-Et2-indenyl)zirconium dichloride (2) and bis (2, 4, 6-Me3-indenyl) zirconium dichloride (3) were synthesized. The effect of solvent polarity on propylene polymerization catalyzed by the metallocenes in the presence of methylaluminoxane(MAO) and triisobutylaluminum(TIBA) was investigated in the toluene/CH2Cl2 mixed solvent. Changing the solvent polarity was found to influence the catalytic activity, polymer molecular weight and stereospecificity of the catalysts. The changes in the position of the substituents on the ligand caused the different responses of the catalyst to the changes in solvent polarity. The isotactic stereosequence of polypropylene was found to increase with the increase in the polarity of the reaction medium.

两种咔唑基-吡啶-N-氧化物内盐荧光极性探针研究

合成了4-(9H-咔唑-9-基)吡啶1-氧化物(CPNO)和4-(4-(9H-咔唑-9-基)苯基)吡啶1-氧化物(CPPNO)两种咔唑基-吡啶-N-氧化物内盐,测定了它们在不同溶剂中的紫外-可见吸收和荧光光谱,均表现出对溶剂极性较好的敏感性。计算表明,两个化合物都具有较大的激发态偶极矩,是化合物溶剂极性敏感性的原因。研究为开发新型的荧光极性探针提供了一种新思路。

氯化胆碱/二醇基低共熔溶剂的理化性质及其结构表征

近年来,低共熔溶剂具有类离子液体特性受到了越来越多的关注,与离子液体相比,低共熔溶剂不仅具有成本低、易合成等优势而且其应用领域更为广泛.为了拓宽其在食品领域中的应用,分别以氯化胆碱作为氢键受体,以乙二醇、1,3-丙二醇、1,4-丁二醇作为氢键供体合成和制备低共熔溶剂体系,利用FTIR和^(1)H NMR研究其氢键作用,并测定了不同温度(303.15~343.15 K)、摩尔比和烷基链长对其理化性质的影响.结果发现,随着二醇含量增加,氯化胆碱/醇基低共熔溶剂中氯化胆碱的氢键作用减弱,二元醇的氢键作用增强,氯化胆碱/乙二醇摩尔比(1∶3)形成的氢键作用比较适宜.并且,随着温度升高,低共熔溶剂的粘度降低,电导率升高,密度无明显变化.在同一温度下,随着烷基链长度的增加,低共熔溶剂的粘度和极性增强,电导率、表面张力、pH降低.随着醇基含量增加,其粘度降低,pH先升高后降低,极性、表面张力无明显变化.研究结果不仅揭示了氯化胆碱/二醇基低共熔溶剂体系的氢键作用,而且理化性质研究可以为其用于萃取领域提供科学指导,具有重要意义和价值.

灰树花醇提物化学成分及其生物活性研究

为探明灰树花发挥活性作用的化学成分及其抗氧化活性和对肿瘤细胞的抑制作用,该文分析了灰树花醇提物不同极性溶剂萃取物的主要化学成分及其对1,1-二苯基-2-三硝基苯肼(DPPH)自由基、2,2’-联氮-双-3-乙基苯并噻唑啉-6-磺酸(ABTS)自由基和羟自由基的清除能力,以及对肝癌细胞(HepG2)和肺癌细胞(A549)的抑制作用。结果显示,乙酸乙酯萃取物和正丁醇萃取物的抗氧化活性最佳,总酚和黄酮的质量分数与抗氧化活性显著正相关(P<0.05);石油醚萃取物和乙酸乙酯萃取物对肿瘤细胞抑制效果最好,三萜和甾醇质量分数与肿瘤细胞抑制作用极显著正相关(P<0.01)。利用超高效液相色谱质谱联用技术(UPLC-MS)从灰树花醇提物中共鉴定出15个化合物,其中芹菜素和表儿茶素可能是灰树花发挥抗氧化作用的主要化学成分,麦角甾醇和过氧化麦角甾醇可能是发挥肿瘤细胞抑制作用的甾体类化合物。该研究结果可为灰树花作为功能食品进一步开发提供理论依据。

全氟聚醚基弹性体研究进展

作为一类具有极低玻璃化转变温度和优异耐极性溶剂性能的新型弹性体,对制备全氟聚醚基弹性体的主要原料——全氟聚醚的结构和分子量进行了简要介绍;对含三嗪环全氟聚醚弹性体、全氟聚醚硅弹性体和全氟聚醚-聚氨酯弹性体三种典型弹性体的结构、合成方法和性能的研究进展进行了总结;最后展望了全氟聚醚基弹性体的发展方向和市场前景。

低共熔溶剂中直接电解分离废白铜制备铜

以氯化胆碱-乙二醇低共熔溶剂(ChCl-EG DES)为电解液,废白铜为阳极,钛片为阴极,在363 K下对废白铜进行了电解分离,并在阴极获得了阴极铜。系统研究了温度和氯化亚铜(CuCl)浓度对ChCl-EG DES黏度和电导率的影响。结果表明,CuCl+ChCl-EG DES的黏度随着温度的升高而减小,随着CuCl浓度的升高而增大,电导率与之正好相反。阳极极化曲线表明,适当提高CuCl浓度可以使Cu和Ni的电位差增大,有利于铜镍的分离,但CuCl浓度过高会导致阳极溶解速率减慢。电解实验发现,当CuCl浓度升高时,直流电耗先减小后增大,电流效率则相反。当CuCl浓度为1 mol/L时,废白铜电解分离的电流效率高达99.1%,而直流电耗低至170.2 kW·h/t。阴极铜的纯度高达99.62%,其表面形貌平整致密。

Lipid extraction and CO_(2)capture with switchable polarity solvent

In this study,lipid extraction and CO_(2)capture are combined using N,N-dimethylcyclohexylamine(DMCHA)as switchable polarity solvent.The effects of operation parameters are discussed according to the CO_(2)absorption/desorption and lipid/DMCHA recovery results.A triphasic models considering lipid,water,and gas phases are established to analyze the kinetic behaviors.The results show that DMCHA is reversible through CO_(2)absorption/desorption,and the enhanced dispersion of droplets and bubbles in water phase improves the lipid/DMCHA recovery and CO_(2)absorption/desorption.The triphasic kinetic models fit well with experimental data,and gas-liquid mass transfer is regarded as the rate-determining step.The lower interfacial areas result in the poorer gas-liquid mass transfer for the DMCHA recovery than lipid recovery process.

白鲜皮不同溶剂提取物的抗菌活性评价

目的:评价白鲜皮不同极性溶剂提取物的抗菌活性。方法:用乙醇、乙酸乙酯、石油醚三种溶剂制备白鲜皮提取物。观察三种提取物对金黄色葡萄球菌抗菌效果,选出抗菌效果最好的提取物,采用二倍稀释法测最小抑菌浓度,用鉴别试剂去鉴别该提取物可能含有的化学成分。结果:三种提取物中抑菌率强弱顺序为石油醚提取物、乙酸乙酯、乙醇提取物,其中乙醇提取物几乎没有抗菌效果。石油醚提取物的最小抑菌浓度为0.125g/mL。初步判定,石油醚提取物中可能含有生物碱、黄酮、油脂、甾体或三萜类化合物。结论:白鲜皮石油醚提取物对金黄色葡萄球菌有较好的抗菌效果,为进一步从脂溶性成分提取分离抗菌有效成分,提供了理论参考。

Advancements in Polymer Science: Synthesis, Characterization, and Biomedical Applications of Homopolymers and Copolymers

Polymer science encompasses a different range of materials critical to industries spanning from packaging to biomedicine. Understanding the synthesis, characterization, and applications of common homopolymers and copolymers is fundamental to advancing polymer research and development. In this comprehensive review, we explore various preparation methods, including free radical, anionic, and cationic polymerization, utilized for synthesizing homopolymers and copolymers. Furthermore, we investigate solvent choices commonly employed for polymer characterization, ranging from neat conditions, polar protic and polar aprotic solvents. We also explored characterization techniques, including Fourier Transform Infrared Spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR), Atomic Force Microscopy (AFM), Differential Scanning Calorimetry (DSC), and Thermogravimetric Analysis (TGA). In addition to industrial applications, we highlight the diverse biological applications of homopolymers, poly(2-hydroxyethyl methacrylate) (pHEMA) and polystyrene, which find its extensive use in biomedicine. By synthesizing and analyzing this wealth of information, this review aims to provide a comprehensive understanding of the synthesis, characterization, and applications of homopolymers and copolymers, with a particular focus on their biological applications. This holistic approach not only contributes to advancements in polymer science and technology but also fosters innovation in biomedicine, ultimately benefiting human health and well-being.

FeSe_(2)/RGO复合材料的制备与电磁波吸收性能分析

本文通过溶剂热反应法在还原石墨烯表面生长了Fe Se_(2),制备出性能稳定的Fe Se_(2)/RGO复合材料。利用矢量网络分析仪测试电磁参数并通过计算发现,当匹配厚度达到3mm时,在7.52GHz处出现最佳反射率为-42.78dB,证明该复合材料在C波段(4~8GHz)有良好的吸收性能。进一步说明Fe Se_(2)/RGO复合材料具备良好的电磁波吸收性能,是一种性能优异的电磁波吸收材料。

Ca-alginate spheres behavior in presence of some solvents and water-solvent mixtures

Immobilization systems more frequently used are calcium alginate spheres. These biocatalysts have many potential applications in the immobilization of enzymes, prokaryotic cells, vegetal and animal cells, algae, organelles and mixtures of these living components. Other applications of immobilized cells imply the use of non aqueous systems. Some bioconversions are carried out in the presence of solvents such as hexane acetone or acetonitrile, or mixtures water-solvents. The aim of this work was to investigate the behaviour of Ca-alginate spheres when put in contact with different solvents (water, diesel, ethanol, methanol, acetone, n-hexane, isopropyl alcohol, THF, acetonitrile, and toluene), or solvent-water mixtures (i.e., ethanol-water), regarding the resistance of the alginate spheres after days of contact. Calcium alginate particles suffered different damages, depending on the solvent they were put in contact. Water did not damaged the Ca-alginate structure with or without Ca present. On the other hand different solvents lost a proportion of volume, i.e., n-hexane (16%), methanol (19%), ethanol (19.5%), toluene (22%), diesel (34%), acetone (765), isopropyl alcohol (80%), THF and acetonitrile (total loss, total destruction). Nor the dielectric constant nor the polarity indexes were capable of explaining the difference on the volume loss or total sphere destruction, except for water-ethanol mixtures.

Solvent Effects on Spectral Property and Dipole Moment of the Lowest Excited State of Coumarin 343 Dye

Steady-state absorption and fluorescence spectra, and time-resolved fluorescence spectra of coumarin 343 （C343） were measured in different solvents. The effect of the solvent on the spectral properties and dipole moment of the lowest excited state of C343 were investigated. It was found that the absorption and fluorescence spectra red-shifted slightly and strongly with increasing solvent polarity, respectively, because the charge distribution of the excited state leaded to the increasing difference between the absorption and fluorescence spectra with increasing solvent polarity. The dipole moment of the lowest excited state of C343 was determined from solvatochromic measurements and the quantum chemical calculation, and the results obtained from these two methods were fully consistent. Investigations of the time-resolved fluorescence of C343 in different solvents indicated that the fluorescence lifetimes increased nearly linearly with 4.45 ns in water. This can be ascribed between C343 and hydrogen donating increasing solvent polarity from 3.09 ns in toluene to to the intermolecular hydrogen bonding interactions solvents

基于2-羟基-苯甲醛肟结构的刺激响应荧光性质研究

利用2-羟基-苯甲醛肟结构具有烯醇-酮式互变异构的特点和环境敏感性,合成了3-(2-苯并噻唑基)-2-羟基-5-甲基苯甲醛肟,研究其在不同极性溶剂中的光物理性质、固体荧光性质和酸碱刺激响应荧光性质,结果表明该化合物具有良好的溶剂极性和酸碱刺激响应荧光性质,在可视化环境检测应用方面有一定潜力。

紫苏叶浸膏挥发性成分分析及其在卷烟配方中的应用

为研究芳香植物紫苏叶浸膏的挥发性香气成分及其在卷烟配方中的应用效果,将新鲜紫苏叶采用不同极性的溶剂浸提浓缩制备得到浸膏组分,利用气相色谱-质谱联用方法(GC-MS)进行挥发性成分分析,进一步研究各浸膏组分在卷烟配方中的应用效果。结果表明:由于浸提溶剂极性不同,制备的各浸膏组分经鉴定得到的挥发性香气成分数量、相对含量及种类均存在差异;应用于卷烟叶组配方烟丝中,紫苏叶无水乙醇浸膏和乙酸乙酯浸膏对卷烟感官品质具有明显增香掩杂作用,主要表现在香韵丰富性、谐调性提升及烟气质感改善等方面。因此,在中式卷烟配方设计与开发过程中,根据需要可合理选择紫苏叶浸膏的制备工艺,以实现卷烟品质的提升。