酸性功能化离子液体催化合成叶青素

以含磺酸基离子液体1-(4-磺酸基)丁基-3-甲基咪唑四氟硼酸盐([4-sulfbmim][BF₄])为酸性催化剂,由乙缩醛和苯甲醇合成了叶青素。 采用正交实验方法考察了合成条件的影响,固定反应温度为20 ℃条件下,确定优化合成条件为：n(苯甲醇)∶n(乙缩醛)=1∶8,反应时间60 min,催化剂用量为每摩尔苯甲醇4 g,产率为92.2%。 与H₂SO₄催化剂相比[4-sulfbmim][BF₄]的催化活性相对较弱,但综合效果优于H₂SO₄。 [4-sulfbmim][BF₄]循环使用6次,催化活性基本不变。     

离子液体-水介质中离子液体负载TEMPO催化选择氧化合成脂肪醇羟基芳香醛和酮

由于脂肪醇羟基和苄醇羟基具有相同的氧化反应活性,所以当分子内同时含有脂肪醇羟基和苄醇羟基时,很难选择氧化苄醇羟基合成含脂肪醇羟基的芳香醛或酮。本文报道了在离子液体-水介质中,NCS/NaBr/IL-TEMPO（离子液体负载TEMPO）催化氧化合成含有脂肪醇羟基的芳香醛、酮的方法,反应条件温和,选择性好,收率高,且离子液体和催化剂可以循环使用。     

羟基聚醚官能化杂多酸聚离子液体催化的连续酯化氧化合成环氧油酸甲酯

以乙二醇、环氧氯丙烷、三甲胺、三乙胺、三乙醇胺、H₄SiW₁₂O₄₀、H₃PW₁₂O₄₀为起始原料,经开环聚合、季铵化、分子自组装,构建了系列羟基官能化聚醚杂多酸聚离子液体HPIL-1～HPIL-6。聚离子液体兼具两亲活性、酸催化活性和氧化催化活性,以其为非均相催化剂,实现了油酸连续酯化、环氧化合成环氧油酸甲酯。当原料比n(甲醇)∶n(H₂O₂)∶n(油酸)∶n(聚离子液体)=500∶120∶40∶1,室温下酯化反应2.5h, 65℃下环氧化反应4h,环氧油酸甲酯产率92%。聚离子液体经离心分离、溶剂洗涤、真空干燥即可再生循环使用,循环使用5次,催化活性基本保持不变。     

离子液体体系中氯化金属卟啉对苯甲醇的催化氧化反应

研究了一种将苯甲醇直接氧化成苯甲醛的催化体系:氯化金属卟啉/离子液体/氧化剂(MTPPCl/ILs/[O]),考察了该体系反应过程中温度、氯化金属卟啉、氧化剂、轴向配体和离子液体的种类等因素对反应收率的影响。结果表明,催化剂氯化锰卟啉、溶剂1-丁基-3-甲基咪唑硫酸氢盐离子液体、氧化剂过硫酸钾组成的催化体系MnTPPCl/[Bmim]HSO4/K2S2O8在苯甲醇直接催化氧化成苯甲醛的反应中表现出很好的活性(99%)和选择性(99%),且该体系避免了使用传统的有机溶剂,可重复多次使用。     

Brφnsted酸性离子液体催化合成长链脂肪酸甲酯

本文合成了以1-丁基-3-甲基咪唑为阳离子,HSO4-、H2PO4-和BF4-为阴离子的Brφnsted酸性离子液体,并以长链脂肪酸与甲醇的酯化反应考察了这些Brφnsted酸性离子液体的催化性能。实验结果表明,1-丁基-3-甲基咪唑硫酸氢根鎓盐([bmim][HSO4])离子液体具有很高的催化活性,当n(醇)∶n(酸)∶n(离子液体)=6∶1∶0.25,反应温度为70℃,不分水酯化反应2h,长链脂肪酸甲酯的产率可达到93.4%以上,选择性达到100%;且产物酯与离子液体分离容易;离子液体经干燥处理后可以循环使用5次以上,催化活性没有明显降低。     

功能离子液体催化分子氧氧化醇为醛酮

2,2,6,6-四甲基-N-氧自由基哌啶醇(2,2,6,6-tetramethyl-piperidin-4-ol-N-oxyl,TEMPO)与氯乙酰氯反应生成2-氯乙酸-2,2,6,6-四甲基-1-氧-4-哌啶醇酯,该酯与N-甲基咪唑发生季铵化反应后再与六氟磷酸钾进行离子交换制得2,2,6,6-四甲基-N-氧自由基哌啶醇负载离子液体TEMPO-IL。温和条件下以离子液体1-甲基-3-丁基咪唑六氟磷酸盐(1-butyl-3-methylimidazolium hexafluorophosphate,[bmim]PF6)为溶剂,TEMPO-IL和CuCl为催化剂,分子氧氧化各种醇为相应的醛或酮。研究发现,该氧化体系对苄醇和烯丙醇有较好的氧化效果,65℃下反应10h左右,转化率可达99%,收率可达80%~90%。氧化体系对醛酮有高度的选择性,在实验所采用的条件范围内未检测到有羧酸生成。溶剂和催化剂可循环使用,在苯甲醇的氧化中,溶剂和催化剂循环使用6次,反应转化率和苯甲醛的收率保持不变。     

氨基醇杂多酸类离子液体催化环酮的Baeyer-Villiger氧化反应

合成了一系列氨基醇杂多酸类离子液体, 并将其用于催化环酮的Baeyer-Villiger氧化反应. 以2-庚基环戊酮为模板底物, H₂O₂为氧化剂, 探究了此类氨基醇杂多酸类离子液体的催化活性, 筛选出催化活性最高的催化剂为[Pro-ps]H₂PW₁₂O₄₀, 最佳反应条件: n(2-庚基环戊酮)∶n(催化剂)∶n(H₂O₂)=1∶0.03∶4, 反应温度40 ℃, 反应时间8 h, 无溶剂. 在最佳条件下, 2-庚基环戊酮的转化率为98.19%, 产物δ-十二内酯的选择性可达82.84%. 水相中的离子液体[Pro-ps]H₂PW₁₂O₄₀经干燥后可以重复使用. 经过5次循环使用后催化活性未见明显下降. [Pro-ps]H₂PW₁₂O₄₀还可用于催化其它多种环酮的Baeyer-Villiger氧化反应, 结果表明, 该催化剂具有良好的重复使用性和底物普适性.     

负载型离子液体在C-H键电氧化活化中的应用研究

本文将1-乙基-3-甲基咪唑醋酸盐离子液体修饰在多壁碳纳米管上,制备出离子液体/碳纳米管复合材料,并研究了对甲氧基甲苯（p-MT）在该复合离子液体水溶液体系中的电氧化性能. 同时,通过循环伏安法和计时电流法考查了扫描速率、温度、反应底物浓度等因素对电氧化性能的影响,研究了p-MT在该体系中的动力学过程. 实验结果表明,p-MT在复合离子液体水溶液体系中发生不可逆的电氧化反应,且该过程受扩散控制,扩散系数为7.69×10^-10 cm²·s^-1. 适当地升高温度和增大反应底物浓度都有利于促进p-MT中C-H键选择性电氧化为相应醛基,选择性可达到95%. 通过在不同结构电解槽中进行恒电位电解研究,发现离子液体/MWCNTs复合电解质在一室型电解槽中进行p-MT电氧化的电解效率更高、对目标产物对甲氧基苯甲醛（p-MBA）的选择性也更好.     

咪唑型离子液体对4–甲氧基甲苯的电氧化性能研究

通过紫外光谱研究了EMIMBF₄、BMIMBF₄、BMIMHSO₄和BMIMAc四种咪唑型离子液体(ILs)与4–甲氧基甲苯（p-MT）之间的相互作用,采用循环伏安法（CV）和计时电流法（CP）研究了p-MT在四种离子液体中的电化学氧化行为,探讨了咪唑型离子液体对反应的影响. 实验结果表明,在离子液体水溶液中p-MT的紫外光谱出现明显的红移,其溶剂分子和反应底物p-MT之间相互作用,这有利于p-MT产生相对稳定的激发态. p-MT在离子液体水溶液中的电氧化受扩散控制,且p-MT在EMIMBF₄水溶液中的扩散系数和电解产物的产率和选择性最佳.     

哌啶型离子液体混合电解液在Li/LiCoO2电池中的性能研究

合成并考察了N-甲基-N-乙（丙,丁）基哌啶-二( 三氟甲基磺酰) 亚胺三种离子液体( PP12（3,4）TFSI )作为电解液添加剂的影响. 使用热分析和电化学技术研究了离子液体混合电解液的热稳定性和电化学性能.实验表明,哌啶型离子液体可以提高有机电解液的热稳定性,并且侧链的长短对 LiCoO₂ 电极的电化学性能有重要的影响.当以PP13TFSI配成的混合电解液,在3.0~4.35 V之间、电流密度为150 mA•g^-1时, LiCoO₂ 电极的首次放电容量为156.6 mAh•g^-1,200周循环后容量为133.9mAh•g^-1,容量保持率为85.5%,远远优于在传统有机电解液中的循环性能.     

Polymeric Ionic Liquid and Carbon Black Composite as a Reusable Supporting Electrolyte: Modification of the Electrode Surface

One of the major impediments to using electroorganic synthesis is the need for large amounts of a supporting electrolyte to ensure the passage of charge. Frequently this causes separation and waste problems. To address these issues, a polymeric ionic liquid–Super P carbon black composite has been formulated. The system enables electrolyses to be performed without adding an additional supporting electrolyte, and its efficient recovery and reuse. In addition, the ability of the composite to modify the electrode surface in situ leads to improved kinetics. A practical consequence is that one can decrease catalyst loading without sacrificing efficiency.     

High‐Activity PtRuPd/C Catalyst for Direct Dimethyl Ether Fuel Cells

Dimethyl ether (DME) has been considered as a promising alternative fuel for direct‐feed fuel cells but lack of an efficient DME oxidation electrocatalyst has remained the challenge for the commercialization of the direct DME fuel cell. The commonly studied binary PtRu catalyst shows much lower activity in DME than methanol oxidation. In this work, guided by density functional theory (DFT) calculation, a ternary carbon‐supported PtRuPd catalyst was designed and synthesized for DME electrooxidation. DFT calculations indicated that Pd in the ternary PtRuPd catalyst is capable of significantly decreasing the activation energy of the C? O and C? H bond scission during the oxidation process. As evidenced by both electrochemical measurements in an aqueous electrolyte and polymer‐electrolyte fuel cell testing, the ternary catalyst shows much higher activity (two‐fold enhancement at 0.5 V in fuel cells) than the state‐of‐the‐art binary Pt₅₀Ru₅₀/C catalyst (HiSPEC 12100).     

Organic ionic plastic crystal as electrolyte for lithium-oxygen batteries

Organic ionic plastic crystal composed of 1-ethyl-1-methyl pyrrolidinium bis(fluorosulfonyl)imide (P₁₂FSI) and lithium bis(fluorosulfonyl)imide (LiFSI) was used as electrolyte for lithium-oxygen battery. The battery at room temperature delivered a superior long life (320 cycles) and good rate capability since the electrolyte had good chemical and electrochemical stability, and high ionic conductivity.     

Direct Electrochemistry of Hemoglobin in Layer‐by‐Layer Films Assembled with DNA and Room Temperature Ionic Liquid

Based on electrostatic interaction and electrodeposition, poly‐anionic deoxyribonucleic acid (DNA), room temperature ionic liquid 1‐butyl‐3‐methyl‐imidazolium tetrafluoroborate (BMIMBF₄), hemoglobin (Hb) and Poly(diallyldimethylammonium chloride) (PDDA) were successfully assembled into Hb/IL/DNA/PDDA layer‐by‐layer complex films on the surface of ITO electrode. FTIR spectroscopy, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were used to characterize the composite film. The obtained results demonstrated that the Hb molecule in the film kept its native structure and showed its good electrochemical behavior. A pair of well‐defined redox peaks of Hb with the formal potentials (E°′) of ?0.180 V (vs. SCE) was appeared in phosphate buffer solution (PBS, pH 7.0). The Hb/IL/DNA/PDDA/ITO modified electrode also showed an excellent electrocatalytic behavior to the reduction of hydrogen peroxide (H₂O₂). Therefore, the IL/DNA/PDDA complex film as a novel matrix open up a possibility for further study on the direct electrochemistry of other proteins and the fabrication of the third‐generation electrochemical biosensors.     

层状碳及层状碳/硫酸铅复合材料的制备与应用

碳酸钾或碳酸钠颗粒作催化剂基底,采用化学气相沉积（CVD）制得类似于石墨烯的层状碳材料,并经原位化学沉积可得层状碳/硫酸铅复合材料. 用X射线衍射（XRD）、热重分析、扫描电镜（SEM）和透射电镜（TEM）分析与测试样品. 结果表明,层状碳为无定型碳层,复合材料为无定型碳层与附着其上的细小硫酸铅颗粒的复合. 上述层状碳和复合材料作为负极添加剂应用于铅酸电池中,测试了电池电化学性能. 结果表明,电池大电流放电比容量和循环寿命均明显提高. 通过电化学交流阻抗谱图（EIS）、充放电曲线和负极失效后的SEM照片证实,加入添加剂能够降低反应阻抗、减小极化及有效抑制极板硫酸盐化.     

Sensitive detection of luteolin based on poly(diallyldimethylammonium chloride)-functionalized graphene-carbon nanotubes hybrid/β-cyclodextrin composite film

Poly(diallyldimethylammonium chloride) (PDDA)-functionalized graphene sheets-multiwalled carbon nanotubes (G-CNTs) hybrid materials (PDDA-G-CNTs) were successfully synthesized. The materials were characterized by transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR) spectra. Then, an electrochemical sensor based on PDDA-G-CNTs/β-cyclodextrin (PDDA-G-CNTs/β-CD) was fabricated for the sensitive determination of luteolin. In 0.2 M HAc–NaAc buffer solution (pH 5.0), the redox peak currents of luteolin increased significantly on PDDA-G-CNTs/β-CD modified glassy carbon electrode (GCE), suggesting that the composite film not only showed excellent electronic properties of PDDA-G-CNTs but also exhibited high molecular recognition capability of β-CD. The chronocoulometry investigation demonstrated that the composite could effectively increase the electrochemical active surface. Under the optimal conditions, the oxidation peak current of luteolin increased linearly with increasing the concentration in the range from 0.05 to 60 μM with the detection limit of 0.02 μM (S/N?=?3). The developed electrochemical sensor exhibited high selectivity, good stability and reproducibility, and also successfully determined luteolin in drug samples.     

Stabilization of high-performance oxygen reduction reaction pt electrocatalyst supported on reduced graphene oxide/carbon black composite

Oxygen reduction reaction (ORR) catalyst supported by hybrid composite materials is prepared by well-mixing carbon black (CB) with Pt-loaded reduced graphene oxide (RGO). With the insertion of CB particles between RGO sheets, stacking of RGO can be effectively prevented, promoting diffusion of oxygen molecules through the RGO sheets and enhancing the ORR electrocatalytic activity. The accelerated durability test (ADT) demonstrates that the hybrid supporting material can dramatically enhance the durability of the catalyst and retain the electrochemical surface area (ECSA) of Pt: the final ECSA of the Pt nanocrystal on the hybrid support after 20?000 ADT cycles is retained at >95%, much higher than the commercially available catalyst. We suggest that the unique 2D profile of the RGO functions as a barrier, preventing leaching of Pt into the electrolyte, and the CB in the vicinity acts as active sites to recapture/renucleate the dissolved Pt species. We furthermore demonstrate that the working mechanism can be applied to the commercial Pt/C product to greatly enhance its durability.     

High-speed carbon nanotube actuators based on an oxidation/reduction reaction

Actuators with a high-speed response under a high-frequency (more than 100 Hz) applied square-wave voltage of ±2 V have been developed with an electrode composed of millimeter-long single-walled carbon nanotubes synthesized by the "supergrowth method" (SG-SWNTs) and ionic liquids (ILs). Detailed studies concerning induced electric current and transferred charge in the electrode as well as cyclic voltammetric studies of the electrode revealed that the high-speed response originates from the electric current generated by an oxidation/reduction (redox) reaction in addition to electric double-layer charging. The contribution of the redox reactions of SG-SWNTs to the actuation is sensitive to the presence of supporting polymers, the thickness of the electrolyte, and the amplitude of the applied voltage.     

碳纳米管/聚二烯丙基二甲基氯化铵/磷钼酸复合膜的组装及其在溴酸盐检测中的应用

通过静电层层组装技术在玻碳(GC)电极表面制备{多壁碳纳米管(MWCNT)/聚二烯丙基二甲基氯化铵(PDDA)}n多层膜,并采用循环伏安法在多层膜的表面电化学修饰一层磷钼酸(PMo12)膜,构筑GC/{MWCNT/PDDA}n-PMo12复合膜修饰电极.利用SEM对比观察{MWCNT/PDDA}n和{PDDA/MWCNT}n-PMo12的微观结构,并研究该复合膜修饰电极的电化学及其对溴酸盐(BrO3-)电催化还原性质.在此基础上研发一种基于GC/{MWCNT/PDDA}n-PMo12复合膜修饰电极的电流型BrO3-传感器,该传感器表现出明显增大的响应电流.在最优的实验条件下,采用电流时间曲线(i-t)法考察该复合膜修饰电极对BrO3-的安培响应.实验结果表明,该传感器在BrO3-浓度为50～400nmol/L的范围内具有良好的线性关系,相关系数R2为0.9950,响应时间为1.53s,检出限为20nmol/L,灵敏度为13.81mA(mmol/L)-1cm-2.