甲醇溶液中五氮唑负离子的制备与表征

以对氨基苯磺酸为起始原料,通过重氮化、缩合和水解反应,合成了3,5-二甲基-4-羟基苯胺盐酸盐,总收率为75%。用3,5-二甲基-4-羟基苯胺盐酸盐制备了-50℃下稳定的3,5-二甲基-4-羟基苯基五唑,收率为66.7%。以甲醇为溶剂,亚铁盐为还原剂,间氯过氧苯甲酸为氧化剂,可切断3,5-二甲基-4-羟基苯基五唑分子中的C—N键,得到少量的五唑负离子,并通过质谱、核磁等方法对其进行表征。同位素标记实验证明五唑环中N原子具有相同的化学环境,说明五唑负离子极有可能具有芳香性。     

High-performance Poly(biphenyl piperidinium) Type Anion Exchange Membranes with Interconnected Ion Transfer Channels: Cooperativity of Dual Cations and Fluorinated Side Chains

The performance of alkaline fuel cells is severely limited by substandard anion exchange membranes (AEMs) due to the lower ionic conductivity compared to the proton exchange membranes. The ionic conductivity of AEMs can be effectively improved by regulating the microphase structure, but it still cannot meet the practical use requirements. Here, enhanced microphase-separated structures are constructed by the cooperativity of highly hydrophilic dual cations and highly hydrophobic fluorinated side chains. Meanwhile, the introduction of  O enhances the flexibility of side chains and facilitates the formation of ion transport channels. The dual piperidinium cation functionalized membrane (PB2Pip-5C8F) which is grafted with the ultra-hydrophobic fluorocarbon chain exhibits a high conductivity of 74.4 mS cm⁻¹ at 30 °C and 168.46 mS cm⁻¹ at 80 °C. Furthermore, the PB2Pip-5C8F membrane achieves the highest peak power density of 718 mW cm⁻² at 80 °C under a current density of 1197 mA cm⁻² without back pressure. A long-term life cell test of this AEM shows a low voltage decay rate of 1.68 mV h⁻¹ over 70 h of operation at 80 °C.     

Catfish Effect Induced by Anion Sequential Doping for Microwave Absorption

Heteroatom doping engineering is desirable in tuning crystal structures and electrical properties, which is considered an opportunity to further develop microwave absorption materials. However, the competition mechanism and priority among doped atoms have not been revealed, which are insufficient to guide the most reasonable dielectric coupling model and design high-performance absorbers. In this work, based on in situ N and O, ex situ S is introduced through external thermal driving, leading to fierce competition among anions. Specifically, S atoms replace pyrrole N, drive out lattice O, and create O vacancies, bringing more extensive local charge redistribution and stronger electron interaction, thus activating the defect-induced polarization (3–6 times higher than conduction loss) in the middle/high-frequency region. Therefore, the effective absorption bandwidth (EAB) of 9.03 GHz and the minimum reflection loss (RL_min) of −64.05 dB at a filling rate of 10 wt.% are obtained, which improves the record of carbon absorbers as reported. Through macro-designs, i.e., multi-layer gradient metamaterial, or utilizing other advantages, e.g., cost-effective, stable chemical properties and wide-angle absorption, porous carbon may possess a great application prospect in the naval field.     

Anodic Electrochromism for Energy‐Efficient Windows: Cation/Anion‐Based Surface Processes and Effects of Crystal Facets in Nickel Oxide Thin Films

Anodic electrochromic (EC) oxides are of major interest as counter electrodes for smart window applications owing to their unique optical properties upon charge insertion and extraction. However, performance optimization of such oxides has been hampered by limited understanding of their EC mechanism, particularly in Li⁺‐conducting electrolytes. This paper reports on NiO_x films with 1.16 ≤ x ≤ 1.32, prepared by sputter deposition. These films are immersed in an electrolyte of lithium perchlorate in propylene carbonate, and EC properties are studied by cyclic voltammetry and in situ optical transmittance measurements. The electrochromism is significantly enhanced at large values of x. It has been found that charge exchange in Ni oxide is mainly due to surface processes and involves both cations and anions from the electrolyte, which is different from the case of cathodic EC materials such as WO₃. Whereas previous studies of Ni oxide have focused on cation intercalation, the cation/anion‐based mechanism presented here offers a new paradigm for designing and developing EC devices such as smart windows for energy efficient buildings.     

A Multiscale-Porous Anion Exchange Membrane for Convenient and Scalable Electrokinetic Concentration of Cationic Species

A device able to electrokinetically concentrate cationic samples has many potential medical and industrial applications, but until now has remained undeveloped due to the lack of a commercial anion-permselective material leading to a prohibitively complex fabrication procedure. Herein, a novel multiscale-porous anion exchange membrane (MP-AEM) that enables the convenient and scalable electrokinetic concentration of cationic species is proposed. A mechanically enhanced multiscale-porous structure with a solid framework is realized by adopting polyester resin as an additive to overcome the intrinsic limitations of the AEM material. The scalable MP-AEM-embedded electrokinetic concentrator is devised based on the peculiar properties of the MP-AEM that for allow both ion and fluid transport. With the MP-AEM, the concentrator is fabricated in a highly streamlined manner consisting only of a simple insertion and assembly. The concentration performance of the MP-AEM-embedded electrokinetic concentrator is demonstrated with a positively charged fluorescent dye and a fluorescein-labeled protein, and the results show enrichment factors of 250 and 500, respectively. The MP-AEM makes cationic electrokinetic concentration more accessible and scalable, thereby enabling further progress in a wide range of fields.     

Poly(arylene piperidinium) Hydroxide Ion Exchange Membranes: Synthesis,Alkaline Stability,and Conductivity

A series of poly(arylene piperidinium)s (PAPipQs) devoid of any alkali‐sensitive aryl ether bonds or benzylic sites are prepared and studied as anion exchange membranes (AEMs) for alkaline fuel cells. First, the excellent alkaline stability of the model compound 4,4‐diarylpiperidinium is confirmed. Medium molecular weight poly(arylene piperidine)s are then synthesized in polycondensations of N‐methyl‐4‐piperidone and either bi‐ or terphenyl via superelectrophilic activation in triflic acid. Film‐forming PAPipQs are subsequently prepared in Menshutkin reactions with methyl, butyl, hexyl, and octyl halides, respectively. AEMs based on poly(terphenyl dimethylpiperidinium) show the best performance with no structural degradation detectable by ¹H NMR spectroscopy after storage in 2 m aq. NaOH at 60 °C after 15 d, and a mere 5% ionic loss at 90 °C. In the fully hydrated state these AEMs reach an OH^? conductivity of 89 mS cm^?1 at 80 °C. The presence of longer pendant N‐alkyl chains (butyl to octyl) is found to significantly promote Hofmann ring‐opening elimination reactions and the degradation rate increases with increasing alkyl chain length. The results of the present study demonstrate that PAPipQs are efficiently prepared from readily available monomers and show excellent alkaline stability and OH^? conductivity when devoid of pendant N‐alkyl chains.     

A High-Voltage,Dendrite-Free,and Durable Zn–Graphite Battery

The intrinsic advantages of metallic Zn, like high theoretical capacity (820 mAh g⁻¹), high abundance, low toxicity, and high safety have driven the recent booming development of rechargeable Zn batteries. However, the lack of high-voltage electrolyte and cathode materials restricts the cell voltage mostly to below 2 V. Moreover, dendrite formation and the poor rechargeability of the Zn anode hinder the long-term operation of Zn batteries. Here a high-voltage and durable Zn–graphite battery, which is enabled by a LiPF₆-containing hybrid electrolyte, is reported. The presence of LiPF₆ efficiently suppresses the anodic oxidation of Zn electrolyte and leads to a super-wide electrochemical stability window of 4 V (vs Zn/Zn²⁺). Both dendrite-free Zn plating/stripping and reversible dual-anion intercalation into the graphite cathode are realized in the hybrid electrolyte. The resultant Zn–graphite battery performs stably at a high voltage of 2.8 V with a record midpoint discharge voltage of 2.2 V. After 2000 cycles at a high charge–discharge rate, high capacity retention of 97.5% is achieved with ≈100% Coulombic efficiency.     

Comparative antioxidant activity of nanoscale lignin prepared by a supercritical antisolvent (SAS) process with non-nanoscale lignin

Nowadays, lignin antioxidant study is a hot spot. But some properties of lignin make it hard for a wide range of application. To improve lignin antioxidant activity, we employed supercritical antisolvent (SAS) method for preparation of nanoscale lignin (0.144 ± 0.03 μm) using acetone as a solvent and supercritical carbon dioxide as an antisolvent. The nanoscale lignin was characterised by Scanning Electron Microscopy (SEM), Fourier-Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD). The results showed that SAS process did not result in lignin degradation or chemical structure change. Due to solubility increase, many antioxidant parameters of the nanoscale lignin were obviously enhanced, including DPPH radical scavenging activity, superoxide radical scavenging activity and reducing power. As an antioxidant, the nanoscale lignin was a better material than the non-nanoscale lignin. Our study was to promote the lignin application in animal husbandry, pharmaceutical and food processing industries.     

负离子纤维纺纱梳理器材的选配与工艺配套

为了解决负离子纤维梳理过程中的梳理效果、转移能力以及棉结、短绒的控制问题等,在详细分析负离子纤维特性的基础上,提出了"强分梳、少损伤、快转移"的工艺原则,重点从锡林针布、盖板针布、道夫针布、刺辊的选配及其工艺参数的合理调整方面论述了梳理负离子纤维的技术要求;并通过梳理效果对工艺进行了优选。     

精梳棉/负离子粘胶纤维紧密纺细特纱的生产

负离子粘胶纤维强伸度低,纺纱与织造困难,从而阻碍了细特高密高档负离子功能性家纺产品的规模化生产.介绍了紧密纺精梳棉与负离子粘胶混纺细特纱的生产技术要点,包括原料选择、纺纱流程和工艺参数选择以及车间温湿度控制等,成纱各项性能指标可达Uster 2007公报25％水平,满足了市场对于高档负离子功能性家纺面料的规模化生产需求...