室温离子液体对氨基苯磺酸的萃取性能

系统研究了[C₄mim][PF₆], [C₆mim][PF₆], [C₆mim][BF₄]和[C₈mim][BF₄]室温离子液体对间氨基苯磺酸、对氨基苯磺酸稀水溶液的萃取平衡. 实验结果表明: 萃取温度和相体积比的变化对分配比影响不大; 水相pH值对萃取平衡有较大的影响, 氨基苯磺酸在离子液体/水体系中的分配比在pH＝4.2时达到最大值; 水相中CaCl₂或Na₂SO₄的存在能较大幅度地提高氨基苯磺酸的分配比; 离子液体的阴离子的性质对分配比有显著的影响, 阴离子为[BF₄]^－的离子液体对氨基苯磺酸的萃取能力大于阴离子为[PF₆]^－的离子液体; 咪唑环上烷基链的长度也对萃取效果有一定的影响. 在所研究的离子液体中, [C₆mim][BF₄]和[C₈mim][BF₄]对氨基苯磺酸有较好的萃取性能, 且萃取相中的氨基苯磺酸可回收利用, 离子液体也可循环使用.     

1-丁基-3-甲基咪唑醋酸盐和水组成的混合电解液中三价铬电沉积铬的研究

本文在[BMIM]OAc-H₂O电解液中研究了Cr³⁺的电沉积反应. 经循环伏安研究表明,Cr³⁺的还原属于受扩散控制的分步还原过程, 即Cr³⁺ + e →Cr²⁺和Cr²⁺ + 2e → Cr⁰. 在40℃下通过Rendle-Sevcik方程计算得到Cr³⁺的扩散系数为1.2×10^-8 cm²/s. 采用计时电流法探讨了Cr的三维瞬时成核机理. 对沉积的铬镀层进行了XRD、SEM表征, 结果表明经600℃氩气保护下煅烧后的镀层由Cr和Cr₂O₃纳米球状颗粒聚集而成, 其平均粒径为0.48μm. 对40℃,-3.0V条件下所得镀层进行EDX检测,发现Cr与O的能级峰十分明显,其中Cr的质量分数为83.8%. 通过在[BMIM]OAc、[BMIM]BF₄和[BMIM]PF₆三种离子液体体系中电镀得到的Cr镀层质量的比较, 表明OAc-的确有利于Cr的电沉积.     

阴离子插层镁铝水滑石结构及相互作用的理论研究

采用密度泛函理论(DFT)计算了MgAl-LDHs层板与无机阴离子(F^-、Cl^-、NO₃^-、CO₃^2-、SO₄^2-)和有机阴离子(水杨酸根离子([HO(C₆H₄)COO]^-)、苯甲酸根离子([(C₆H₅)COO]^-)、对二甲氨基苯甲酸根离子([p-(CH₃)₂N(C₆H₄)COO]^-)、十二烷基磺酸根离子[C₁₂H₂₅SO₃]^-、己烷基磺酸根离子[C₆H₁₃SO₃]^-、丙烷基磺酸根离子[C₃H₇SO₃]^-)间的相互作用,获得稳定超分子几何结构及相互作用能。层板主体与客体间存在较强的超分子作用,包括主客体间静电作用和氢键等。主、客体间相互作用能数值大小顺序为CO₃^2- > SO₄^2- > F^-> Cl^-> NO₃^-;[p-(CH₃)₂N(C₆H₄)COO]^-> [(C₆H₅)COO]^-> [HO(C₆H₄)COO]^-和[C₁₂H₂₅SO₃]^-> [C₆H₁₃SO₃]^- > [C₃H₇SO₃]^-。另外,还采用自然键轨道(NBO)计算和分析了LDHs 层板与阴离子间作用机理,从二阶微扰理论计算得到的稳定化能变化趋势与相互作用能数据基本吻合。     

离子液体型表面活性剂研究

以1-甲基咪唑为原料, 制备了6个常规离子液体: 1-正丁基-3-甲基咪唑四氟硼酸盐及六氟磷酸盐(简称[bmim][BF₄]及[bmim][PF₆])、1-正己基-3-甲基咪唑四氟硼酸盐及六氟磷酸盐(简称[hmim][BF₄]及[hmim][PF₆])、1-正十六烷基-3-甲基咪唑四氟硼酸盐及六氟磷酸盐(简称[C₁₆mim][BF₄]及[C₁₆mim][PF₆])和4个功能化离子液体: 1-(2-羟乙基)-3-甲基咪唑四氟硼酸盐及六氟磷酸盐(简称[2-hemim][BF₄]及[2-hemim][PF₆])、1-乙氧羰基甲基-3-甲基咪唑四氟硼酸盐及六氟磷酸盐(简称[eocmmim][BF₄]及[eocmmim][PF₆]). 研究了这两类离子液体的一些物理性能, 旨在挖掘离子液体在香料香精化妆品工业中的应用价值. 分别检测了它们与一般溶剂的互溶性, 并测定了它们的表面张力和发泡性能, 实验结果表明, 仅[C₁₆mim][BF₄]和[C₁₆mim][PF₆]具有发泡性能, 发泡力分别为68和120 mm.     

刺五加寡糖的电喷雾多级串联质谱研究

采用小柱层析法从刺五加中分离得到刺五加寡糖类系列化合物(刺五加二糖刺五加六糖).实验结果表明,在正离子模式下的ESI-MS谱中,此类化合物呈现出特征的加合离子峰簇[M+Na]⁺/[M+K]⁺或[M+H₂O+Na]⁺/[M+H₂O+K]⁺,可以确定其分子量;在负离子模式下的ESI-MS谱中,刺五加寡糖易形成[M-H]^-/[M+nH₂O-H]^-(n<3).还利用电喷雾多级串联质谱(ESI-MSⁿ)对刺五加三糖进行了系统的研究,推断出刺五加三糖的组成与结构.     

离子液体增塑生物基聚丁内酰胺的热分解机理

采用疏水性1-丁基-3-甲基咪唑六氟磷酸盐([BMIM]PF₆)和亲水性1-丁基-3-甲基咪唑四氟硼酸盐 ([BMIM]BF₄)两种咪唑类离子液体(IL)增塑聚丁内酰胺(PBL), 探讨了IL对PBL结晶性能及热性能的影响. 研究发现, 两种IL都会削弱PBL分子间氢键, 并抑制PBL晶体在(200)晶面的生长, 降低PBL结晶度. 当IL添加质量分数为5%时, 增塑膜熔点下降7~8 ℃. 与纯PBL膜相比, [BMIM]BF₄增塑PBL膜热稳定性下降, 而[BMIM]PF₆增塑PBL膜的热稳定性提高. [BMIM]PF₆增塑PBL膜热分解过程的热动力学分析结果表明, 其热分解反应活化能为46.68 kJ/mol, 反应级数为1, 热分解最概然机理函数模型符合Mampel单行法则(一级), 即PBL受到热刺激后, 在聚合物和分解产物界面无规律成核, 反应核心具备反应活性, 随后反应逐步扩大, 直至结束.     

折叠型双银配合物电子结构与相关性质

在密度泛函B3LYP/LanL2DZ的水平上,对具有π-π弱相互作用调控的折叠型银配合物Ag₂(MPTQ)₂²⁺进行计算研究。探讨该配合物的电子结构、成键特征、π-π弱相互作用机理、电荷布居及其相关性质。计算结果表明,Ag…Ag之间存在弱的直接相互作用,HOMO主要布居在配体中芳香环的σ-p轨道、S的σ-p轨道及与S相连的C12的S轨道上,LUMO主要布居在配体中芳香环的π^*-p轨道上,基态电子光谱主要是配体中的n→π^*跃迁产生的电荷转移光谱。论文还讨论了分子间π-π弱相互作用的本质及活性部位等。计算结果能较好地解释实验现象与规律。     

离子液体对木瓜蛋白酶催化特性的影响

研究了以1-丁基-3-甲基咪唑、四乙基铵及N-乙基吡啶为阳离子, 配以多种阴离子(H₂PO₄^-, ClO₄^-, HSO₄^-, CH₃COO^-, Cl^-, Br^-, NO₃^-, SCN^-, BF₄^-, PF₆^-)的离子液体对木瓜蛋白酶催化N-苯甲酰-L-精氨酸乙酯(BAEE)水解的活性及热稳定性的影响. 通过分析含离子液体体系中木瓜蛋白酶的水解活性和热力学失活参数, 发现该酶活性及稳定性与离子液体的Kosmotropicity性质无关. 因此, 离子的Hofmeister效应并不适合解释离子液体对木瓜蛋白酶催化特性的影响规律. 当以BF₄^-为阴离子, 改变阳离子结构时, 仅[BMIm][BF₄]可提高酶活性, 其它含官能团的咪唑类离子液体则降低酶活性, 但大部分离子液体明显提高木瓜蛋白酶的热稳定性. 在所研究的离子液体中, 基于PF₆^-或BF₄^-阴离子的离子液体可提高木瓜蛋白酶的活性及其热稳定性. 在含[BMIm][PF₆]介质中, 木瓜蛋白酶的水解活性最高; 在含[HOEtMIm][BF₄]介质中其热稳定性最好.     

1-辛基-3-甲基咪唑离子液体作为可循环溶剂萃取/去除水中二价汞研究

本研究采用1-辛基-3-甲基咪唑离子液体([C₈MIM]PF₆)建立了水中Hg²⁺的循环去除方法. 首先使用[C₈MIM]PF₆萃取水中Hg²⁺, 随后通过甲酸的还原反应, 去除萃取到[C₈MIM]PF₆中的Hg²⁺, 进而实现[C₈MIM]PF₆的回收与循环使用. 本研究优化了萃取与还原去除条件, 考察了最佳条件下[C₈MIM]PF₆的循环使用能力. 结果表明, 50 mL水中加入1 mL[C₈MIM]PF₆同时加入0.2 mL 1-甲基咪唑, 50 ℃、220 r/min震荡2 h, 对Hg²⁺的萃取效率接近100%. 随后在离子液体中加入4 mL, 40%甲酸溶液, 50 ℃下220 r/min震荡30 min, 可以将[C₈MIM]PF₆中60%～70%的Hg²⁺还原去除. 采用这一方式对水中Hg²⁺进行循环萃取, 在9次萃取中,[C₈MIM]PF₆对Hg²⁺的去除效率保持在83%～98%. 因此, 本方法不仅实现[C₈MIM]PF₆对水中Hg²⁺的去除, 同时实现了[C₈MIM]PF₆的回收与循环使用, 避免了[C₈MIM]PF₆过度使用所带来的环境问题.     

反气相色谱法测定有机溶剂在离子液体1-丁基-3-甲基咪唑六氟磷酸盐中的热力学参数

在343.15~373.15 K温度范围内,采用反气相色谱法(IGC)测试了18种有机溶剂在离子液体1-丁基-3-甲基咪唑六氟磷酸盐([BMIM]PF₆)中的热力学参数。在测试温度范围内计算了有机溶剂与[BMIM]PF₆之间的摩尔吸收焓、质量分数活度系数、Flory-Huggins相互作用参数、偏摩尔混合焓和无限稀释活度系数等热力学参数。结果表明,所选的有机溶剂中,正构烷烃、环己烷、四氢呋喃、乙醚和四氯化碳为[BMIM]PF₆的不良溶剂。 相比之下,苯、甲苯、间二甲苯、二氯甲烷、丙酮、氯仿、乙酸乙酯、乙酸甲酯、乙醇和甲醇是[BMIM]PF₆的良溶剂。     

Das perfluortriazinium-kation als oxidationsmittel in der metallorganischen synthese—ein neuer weg zur darstellung von [Cp2MCl2](M = Mo

The oxidation of Cp₂MCl₂ (M= Mo, W) with perfluortriazinium tetrafluoroborate, [(FCN)₃F]⁺[BF₄]⁻, in the presence of a flouride ion acceptor (BF₃ or PF₅) in SO₂ solution yielded the cationic metallocene complexes [Cp₂MCl ₂]²⁺[BF₄]⁻ or [C_p2MCl₂] ²⁺[BF₄]⁻[PF₆]⁻ (M = Mo, W), respectively. In these reactions, for the first time the perfluortriazinium cation has proved to be easy to handle and a useful oxidizer in organometallic chemistry. The oxidizer strength of three fluorotriazinium cations, [(XCN)₃F]⁺ (X = F, Cl, H), has been computed ab initio (HF/6 − 31 + G) and calibrated on literature data which were obtained by local density functional calculations. It was anchored to its F⁺ zero point by an experimental value for KrF⁺. ab]Die Oxidation von Cp²MCl₂ mit (M = MO, W) Perfluortriaziniumtetrafluoroborat, [(FCN)₃F]⁺[BF₄]⁻, in Anwesenheit eines Fluoridionenakzeptors (BF₃ oder PF₅) führte in SO₂-Lösung zur Bildung der kationischen Metallocen-Komplexe [Cp₂MCl₂₊]²⁺[BF₄]₂⁻ bzw. [Cp₂MCl₂]²⁺[BF₄]⁻ [PF₆]⁻ (M = Mo, W). In diesen Reaktionen konnte erstmals gezeigt werden, daß Perfluortriazinium-Kationen einfach zu handhabende und nützliche Oxidationsmittel im Bereich der metallorganischen Synthese darstellen. Das (Mdationsvermögen von drei Fluorotriazinium-Kationen, [(XCN)₃F]⁺(X = F, Cl, H), wurde ab initio berechnet (HF/6 − 31 + G) und mit Hilfe von Literaturdaten, die mittels local density functional-Berechnungen erhalten und am experimentellen Wert von KrF ⁺ bezüglich des F⁺ Nullpunktes verankert wurden, kalibriert.     

模拟油品氧化脱硫及反应动力学研究

在H₂O₂/WO₃/ZrO₂氧化体系中对以甲苯为溶剂、二苯并噻吩(DBT)为模型含硫化合物的模拟油品(硫的质量分数为1540×10^-6)进行了氧化脱硫研究,考察了反应温度、反应时间、氧化剂加入量、催化剂用量对DBT转化率的影响。实验结果表明,在反应温度50℃,反应时间90min,氧化剂加入量油/H₂O₂的体积比为20∶1和催化剂用量0.02g/mL的适宜氧化脱硫条件下,96%以上的DBT氧化为容易分离脱除的二苯并噻吩砜(DBTOs);同时研究了DBT氧化反应动力学,得知DBT氧化反应为一级反应,表观活化能E_a为55.37kJ/mol,指前因子A为3.35×10⁷min^-1。     

氨基酸功能化磷钨酸盐的制备及其催化氧化脱硫性能

以L-丙氨酸和磷钨酸为原料,合成氨基酸功能化磷钨杂多酸盐([Ala]3PW),并采用XRD、FT-IR对其结构进行表征。以[Ala]3PW为催化剂,过氧化氢作为氧化剂,甲基咪唑四氟硼酸盐([HMIM]BF4)为萃取剂氧化萃取一体法脱除模拟油中的二苯并噻吩(DBT)。考察了反应温度、催化剂加入量、O/S物质的量比、萃取剂加入量、硫化物类型等因素对脱硫效率的影响。结果表明,在模拟油为10mL、[Ala]3PW=0.04g、O和S的物质的量比为6、V([HMIM]BF4)/V(oil)=0.6、反应温度50℃、反应时间180min的条件下,DBT的转化率可达到98.2%。催化剂循环使用4次活性没有明显的降低。     

Crystal Structures,Thermal Analysis and Electrochemical Behaviors of Functionalized Pyridinium Ionic Liquids Comprising One 1-Ethyl Acetate Group

Pyridinium ionic liquids(ILs, 1-ethyl acetate pyridinium hexfluorophosphate[EAPy][PF₆] and 1-ethyl acetate-3-methyl pyridinium hexfluorophosphate[EAMPy][PF₆]), were synthesized by a two-step process involving introduction of one ethyl acetate group and anion metathesis. Colorless single crystals of the two ILs were initially obtained using the solvent-evaporation method in mixed solvents. Single-crystal X-ray diffraction was used to determine the crystal structures.[EAPy][PF₆] crystallizes in the monoclinic space group C2/c with a=2.2748(16) nm, b=0.6204(4) nm, c=1.8552(12) nm and Z=8, whereas[EAMPy][PF₆] crystallizes in the orthorhombic space group P2₁2₁2₁ with a=0.7126(17) nm, b=1.2792(3) nm, c=1.5327(3) nm and Z=4. The structure of[EAPy][PF₆] contains double zigzag chains formed by alternately pairing large organic cations with the octahedral anions of[P1F₆]^- or[P2F₆]^-. The[P1F₆]^- and[P2F₆]^- anions occupy respectively two distinct crystallographic sites in crystal packing models. The structure of[EAMPy][PF₆] includes ladder-type chains constructed through pairing pyridinium cations with inorganic anions of[PF₆]^-. The[PF₆]^- anion in[EAMPy][PF₆] shows a distorted octahedron structure and is sandwiched by ethyl acetate groups in crystallographic stacking. This study reveals the influence of chemical mo-dification involving the methyl group(CH₃) onto crystallographic structure of pyridinium ILs. Thermal analysis indicates that the difficult crystallization of the two ILs is related to the low void filling of ion pairs in crystal structure, leading to relatively low melting point and evident supercooling during the cooling process. Additionally, the experimental results indicate that the two ILs have electrochemical activity. The ethyl acetate group also allows downward shifting of electrochemical windows to less negative positions and the ionic conductivities of the two ILs follow an Arrhenius-type behavior.     

Synthesis and Characterization of [Cu(N-MeIm)4(BF4)2] in Ionic Liquid

A new transition metal complex, [Cu(N-MeIm)₄(BF₄)₂](N-MeIm=N-methylated imidazoles, BF₄= tetrafluoroborate), was synthesized via the solvothermal method in ionic liquid. The ionic liquid acts as thermal decomposition reaction medium, soft temple agent and ligand compound. The central Cu(II) ion is coordinated by four N atoms from four N-methylated imidazole ligands, and the four N-methylated imidazole rings are perpendicular to each other. The crystal structure of [Cu(N-MeIm)₄(BF₄)₂] was determined by single crystal X-ray diffraction. The results of thermogravimetry(TG) and Fourier transform infrared spectrometry(FTIR) analyses were in accordance with that of crystal structure. The complex showed strong ligand-based absorbance with maximum wavelength at 208 and 231 nm, which are attributed to π-π^* transition of the N-methylated imidazole ligands.     

离子液体耦合有机过氧化物脱除二苯并噻吩的研究

以12-磷钨酸为催化剂,研究了离子液体耦合有机过氧化物脱除二苯并噻吩(DBT)。研究结果表明,单独使用离子[bmim]BF4、[bmim]PF6液体为萃取剂,脱硫率为27.78%~38.76%。以由等体积的H2O2与甲酸制成有机过氧化物为氧化剂,不使用催化剂和离子液体,温度70℃,反应时间6 h,DBT氧化为二苯并噻吩砜的比例为76.6%。在催化剂作用下,将离子液体与氧化剂耦合使用时,脱硫率明显提高。当催化剂与DBT的摩尔比为0.20∶1,氧化剂与DBT的体积比为10∶1,[bmim]PF6离子液体与DBT的体积比为1∶1,在70℃反应6 h后,脱硫率可达98.60%。耦合体系重复使用五次后,氧化脱硫活性没有明显降低。     

γ-Radiation effect on ionic liquid [bmim][BF4]

The effect of γ radiation on 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF₄]) was investigated in detail. It was found that radiation induced an increase of UV absorption of the ionic liquid but no change in its glass transition point. Raman spectroscopy analysis indicates that the radiolysis of [bmim][BF₄] induces detectable destruction of alkyl-chain and scission of H-atoms of ring of imidizolium cation, and the relatively small changes of BF₄⁻ anion. Viscosities of irradiated [bmim][BF₄] samples were measured at different shear rates and temperatures, and compared with irradiated [bmim][PF₆] samples. The plots of shear stress against shear rate indicates that [bmim][BF₄] is a Newtonian fluid, no matter with irradiation. The viscosity of irradiated [bmim][BF₄] decreased with increasing of temperature and followed an Arrhenius equation. However, radiation caused no change in the viscosity of [bmim][BF₄], but a decrease in the viscosity of [bmim][PF₆] by up to 10%. We conclude that the radiation stability of [bmim][BF₄] is higher than [bmim][PF₆].     

Copper thioether chemistry: Synthesis and X-ray crystal structures of binuclear copper(I) complexes [Cu2(L)] {L = [24]aneS8, [28]aneS8} incorporating octathia macrocycles

Reaction of L {L = [24]aneS₈, [28]aneS₈} with two molar equivalents of [Cu(NCMe)₄]X (X⁻ = ClO₄⁻, BF₄⁻, PF₆⁻) in MeCN affords the white binuclear copper(I) complexes [Cu₂(L)]²⁺. A single crystal X-ray structure determination of [CU₂([24]aneS₈)](BF₄)₂ shows two tetrahedral copper(I) centres, each of which is coordinated to four thioether sulphur-donors, Cu---S(1) = 2.263(3), Cu---S(4) = 2.363(3), Cu---S(7) = 2.349(3), Cu---S(10) = 2.261(3) Å. The Cu … Cu distance is 5.172(3) Å. A single crystal X-ray structure determination Of [CU₂([28]aneS₈)](ClO₄)₂ shows that this complex also contain two tetrahedral copper(I) centres, each coordinated to four thioether sulphur-donors, Cu---S(1) = 2.278(5), Cu---S(4) = 2.333(5), Cu---S(8) = 2.328(5), CU---S(11) = 2.268(5) Å. The Cu … Cu distance of 6.454(3) Å is greater than in [CU₂([24]aneS₈)]²⁺ , reflecting the greater cavity size in [CU₂([28]aneS₈)]²⁺. Cyclic voltammetry of [CU₂([24]aneS₈)]²⁺ and [CU₂([28]aneS₈)]²⁺ at platinum electrodes in MeCN (0.1 M ⁿBU₄NPF₆) shows irreversible oxidations at E_pa, = +0.88 V, +0.92 V vs Fc/Fc⁺, respectively, at a scan rate of 200 mV s⁻¹. Coulometric measurements in MeCN confirm these oxidations to be two-electron (one electron per copper) processes to give binuclear copper(II) species. Oxidation of the binuclear copper(I) precursors with H₂SO₄ or HNO₃ affords ESR-active copper(II) species which presumably incorporate SO₄²⁻ and NO₃⁻ bridges.     

Bis(η-pentamethylcyclopentadienyl)-and(ηcyclopentadienyl) (η-pentamethylcyclopentadienyl)-platinium dications: Pt(IV) metallocenes

Reaction of [Pt₂(η⁵-C₅Me₅)₂(η-Br)₃]³⁺(Br⁻)₃ with C₅R₅H (R = H,Me) in the presence of AgBF₄ gives the first platinocenium dications, [Pt(η⁵-C₅Me₅)(η⁵-C₅R₅)]²⁺(BF₄⁻ )₂. On electrochemical reduction, [pt(η⁵-C₅Me₅)₂]²⁺ yields [Pt(η⁴-C₅Me₅H)(η²-C₅Me₅)]+ BF₄⁻. kw]Cyclopentadienyl; Metallocenes; Platinum; Electrochemistry