杯芳烃钕/二正丁基镁/六甲基磷酰胺催化4-乙烯基吡啶的均聚及其与苯乙烯的共聚

聚4-乙烯基吡啶[P（4-VP）]是一种功能高分子,由于在吡啶环上有一个碱性的氮原子,它能进一步与酸反应生成各种盐,与卤代烃生成季铵盐以及与金属离子生成配合物,可用作高分子电解质,高分子试剂,高分子功能材料等,因此有不少文献对它的合成进行了报道,合成聚4-乙烯基吡啶及其与苯乙烯（St）的共聚物,除了用丁基锂作引发剂外,过渡金属的Ziegler-Natta催化剂,以及烷基铝和烷基锌等也常被用作催化剂,但用这些催化剂催化所得的聚4-乙烯基吡啶及其与苯乙烯的共聚物产率低,分子量小。     

聚(4-乙烯基吡啶)诱导一步法合成纺锤形钨酸钡晶体

利用高分子量的含氮杂环聚合物聚(4-乙烯基吡啶)(P4VP)作为模板合成了纺锤形钨酸钡晶体,为制备形貌可控的钨酸钡晶体提供了一种简单、条件温和、容易控制的方法.用扫描电镜、透射电镜及X-射线衍射等手段研究了钨酸钡晶体的晶型及形貌.并讨论了P4VP的浓度、溶液离子浓度、pH值等因素对钨酸钡晶体形貌的影响.     

酪氨酸酶催化对位取代苯酚和芳香胺的反应及其意义

用固定化酪氨酸酶催化4－取代烷基或烷氧基单酚类化合物的氧化反应得到相 应的4-取代邻苯醌，这类邻苯醌能和芳香胺发生迈克尔加成反应，烷基或烷氧基从 醌环4位上脱落，得到三取代胺的化合物。将抗炎药布洛芬引入到单酚的苯环4位上 ，在酪氨酸酶和芳香胺同时存在的条件下，也得到脱布洛芬的加成取代产物，显示 4－羟基布洛芬苯酚酯可作为布洛芬药物载体。     

T(4-Mop)PS4卟啉与牛血清蛋白相互作用的研究

以四-(4-甲氧基-3-磺酸基苯)卟啉(T(4-Mop)PS4)为探针,通过T(4-Mop)PS4与牛血清白蛋白(BSA)的相互作用,建立了测定BSA的电化学分析方法。T(4-Mop)PS4的峰电流变化(ΔIp)与BSA在2.0×10-6～1.0×10-5mol.L-1范围内呈良好的线性关系,检出限为1.2×10-6mol.L-1;对5.0×10-6mol.L-1BSA平行测定8次,其相对标准偏差为2.0%,回收率为95%～104%。组氨酸、缬氨酸、苯丙氨酸、丝氨酸、异白氨酸、谷氨酰胺、苏氨酸等氨基酸对BSA的测定不产生干扰。采用紫外可见光度法、荧光光谱法和线性扫描伏安法(LSV)研究了T(4-Mop)PS4与BSA之间的相互作用,并测定了二者相互作用的结合常数和结合比。研究表明,T(4-Mop)PS4与BSA之间主要以疏水作用力结合,形成了1∶1的稳定复合物。     

新型球状磷酸铁锂的合成及电化学性能

在水热条件下,制备了水合碱式磷酸铁微球,500 oC焙烧后生成直径为5μm的碱式磷酸铁,接着与碳酸锂一起焙烧后生成了球形磷酸铁锂．我们的方法可以有效地控制所获得产物的尺寸和形貌,同时在产物表面形成均匀碳包覆,改善了磷酸铁锂的电化学性能．     

Stabilization Studies on Divalent Five‐Membered Rings C4H4C,C4H4Si,C4H4Ge,C4H4Sn,and C4H4Pb

Energy differences, ΔX_S‐t (X = E, H and G) (ΔX_S‐t = X_(singlet)‐X_(triplet)) between singlet (s) and triplet (t) states are calculated at B3LYP/6‐311++G (3df,2p). The DFT calculations show that the triplet state of C₄H₄C is a ground state with planar conformer respect to its corresponding nonplanar singlet state. Both singlet and triplet states of C₄H₄M (M = Si, Ge, Sn and Pb) have a planar conformer with the singlet ground state. Four isodesmic reactions are presented for determining the stability energies, SE. NICS calculations are carried out for C₄H₄M to determine the aromatic character.     

EuSO4的干法合成及晶体结构

EuSO₄不同于一般的二价稀土化合物,对水、空气稳定,便于实用。已报道的EuSO₄制备均为湿法^[1~4]。EuS₄的干法合成的结果有助于考察湿法合成中水对EuSO₄的结构与性质的可能影响。     

Tetrabutylammonium bromide: An efficient, green and novel media for polycondensation of 4-(4-dimethylaminophenyl)-1,2,4-triazolidine-3,5-dione with diisocyanates

This is the first report of application of molten ionic liquid (MIL) for the synthesis of heterocyclic polyureas. An inexpensive and readily available MIL, tetrabutylammonium bromide (TBAB) was used for the synthesis of polymers. Therefore, polycondensation of 4-(4-dimethylaminophenyl)-1,2,4-triazolidine-3,5-dione (DAPTD) with various commercially available diisocyanates was performed in molten TBAB with or without dibutyltin dilurate (DBTDL) as a catalyst. The polymerization reaction gave similar results in the presence or absence of DBTDL, indicating that, the catalyst was not needed in this process. Various polyureas were obtained with high yields and moderate inherent viscosities ranging from 0.26 to 0.38 dL/g. This method was compared with the polymerization reaction in conventional solvent and in the presence of DBTDL as a catalyst. In the case of using TBAB, higher yields and inherent viscosities were obtained. This process was safe and green since toxic and volatile solvent such as N,N-dimethylacetamide (DMAc) was eliminated.     

Synthesis and Crystal structure of Poly{[Co(4,4''-bpy)(H2O)4]SO4((4-abaH)2(3H2O}

The title complex has been obtained by the reaction of cobalt sulfate heptahydrate with 4,4'-bpy and 4-abaH (4,4'-bpy = 4,4'-bipyridine, 4-abaH = 4-aminobenzonic acid) in ethanol solution, and its structure was determined by X-ray crystallography with the following data: tetragonal, space group P42/n, Mr = 5692.46, Co8C192H288N32O120S8, a = b = 16.402(5), c = 22.750(5) (A), Z = 1, V = 6120(2) (A)3, F(000) = 2968, Dc = 1.544 g/cm3,μ = 0.707 mm- 1, the final R = 0.0786 and wR = 0.1935 for 2673 observed reflections (I ＞ 2σ(I)). The title complex consists of polymeric [Co(4,4'-bipy)(H2O)4]2+ cation chains, SO42- anions, lattice 4-abaH and water mole cules. The center CoⅡ ions are connected by bridging 4,4'-bpy ligands exhibiting one-dimensional chains, and coordinated by four water molecules into a distorted octahedral geometry. These chains are further extended by hydrogen bonds among SO42- anions, coordinated and lattice water molecules as well as lattice 4-abaH molecules into a three-dimensional network.     

苯乙烯与4-氨基苯酚的氢氨甲基化反应研究北大核心CSCD

氢氨甲基化反应(HAM)是由简单烯烃、胺和合成气一锅法合成有价值胺的方法,具有较高的原子经济效率.然而,4-氨基苯酚作为一种特殊的反应底物,因其同时具有羟基和胺基官能团,在羰基化反应过程中能够选择性地在不同位点发生反应获得不同的产物.因此,我们系统研究了4-氨基苯酚与烯烃的HAM,通过筛选反应参数,确定了最优反应条件,并通过调控添加剂种类,选择性地在4-氨基苯酚的不同活性位点发生反应.结果表明,以甲醇为溶剂,三(3-甲氧基苯基)膦为配体,RhCl(PPh_(3))_(3)为催化剂前驱体,合成气压力4 MPa(H_(2)∶CO=3∶1),反应温度100℃,反应时间20 h时,该催化体系具有最高的反应活性.当以CH3COOH作为添加剂时,选择性的4-氨基苯酚的胺基官能团发生氢氨甲基化反应得到产物4-[(2-苯丙基)氨基]苯酚,收率为82%;当以DBU作为添加剂时,得到苯乙酮产物,收率为92%.最后,提出了该反应可能的机理,为4-氨基苯酚的选择性反应提供理论依据.     

4-甲基咪唑磁性表面分子印迹聚合物的制备及其应用

以4-甲基咪唑(4-MI)为模板分子,甲基丙烯酸(MAA)为功能单体,利用Fe₃O₄磁性纳米微球制备了具有特异性识别能力的磁性表面分子印迹聚合物(MIP),并用红外光谱(FT-IR)、X-射线衍射(XRD)、透射电子显微镜(TEM)和振动样品磁强计(VSM)对聚合物进行了表征,结果显示磁性载体表面包覆了分子印迹聚合物薄层。用紫外分光光度法对4-MI与MAA的相互作用进行了分析,结果表明主客体主要存在形式为1个4-MI被1个MAA所包围。通过紫外分光光度法对磁性印迹聚合物的吸附性能进行了研究,静态吸附平衡实验和Scatchard分析结果表明Fe₃O₄@(4-MI-MIP)中存在两类不同的结合位点,最大吸附量分别为40.31 mg/g和23.07 mg/g,平衡解离常数分别为64.85 mg/L和30.41 mg/L。动力学研究表明准二级动力学方程能较好地拟合动力学实验结果,该过程符合准二级动力学模型。该磁性印迹聚合物应用于环境水样中4-MI的吸附,取得了较满意的结果。     

ZnMn2O4纳米催化剂制备及催化合成乙酸正丁酯

本文以共沉淀法制备了四方晶系锌锰复合氧化物ZnMn2O4纳米催化剂。采用X射线粉末衍射(XRD)和透射电子显微镜(TEM)测试技术对样品进行了分析表征,结果表明所合成的催化剂为粒径均匀的纳米粒子,平均粒径在20-50 nm,具有较好的分散性。实验考察了所制备的ZnMn2O4纳米催化剂对乙酸和正丁醇酯化反应的催化活性,表明ZnMn2O4对乙酸正丁酯的合成有较高的催化活性;探讨了催化剂焙烧温度、催化剂用量、酸醇摩尔比以及反应时间对酯化率的影响,确定了适宜的酯化反应条件,以焙烧温度为300 ℃制备的ZnMn2O4为催化剂,在催化剂用量为0.3%(以反应物总质量计)、酸醇摩尔比n(酸):n(醇)=1.8:1、反应时间为4 h、酯化反应温度120 ℃的条件下,酯化率可达92.53%。     

Preparation of P4VP-g-PSt Copolymer Microspheres with Controllable Size by Atom Transfer Radical Polymerization Synthesized Poly(4-vinylpyridine) Macromonomer

Poly(4‐vinylpyridine) macromonomer (St‐P4VP) with a styryl end group was synthesized by atom transfer radical polymerization (ATRP) of 4‐vinylpyridine using p‐(chloromethyl)styrene (CMSt) as functional initiator, CuCl as catalyst and tris[2‐(dimethylamino)ethyl]amine (Me₆TREN) as ligand in 2‐propanol. The structure of St‐P4VP macromonomer was identified by proton nuclear magnetic resonance (¹H NMR). The result of gel permeation chromatography (GPC) illustrated that the number‐average molecular weight of St‐P4VP could be controlled by adjusting polymerization conditions. Poly(4‐vinylpyridine) grafted polystyrene microspheres (P4VP‐g‐PSt) were then prepared by dispersion copolymerization of styrene with St‐P4VP macromonomers. The effects of polymerization reaction parameters such as medium polarity, concentration of St‐P4VP macromonomer and polymerization temperature on the sizes and size distribution of P4VP‐g‐PSt microspheres were investigated. The results of transmission electron microscopy (TEM), scanning electron microscopy (SEM) and laser light scattering (LLS) indicated that mono‐dispersed P4VP‐g‐PSt microspheres with average diameters of 100–200 nm could be obtained when the molar ratio of St to St‐P4VP was 0.25:100 in ethanol/water mixed solvents (V/V=80:20) at 60°C. Such kind of graft copolymer microspheres was expected to be applied to many fields such as drug delivery system and protein adsorption/separation system due to their particular structure.     

Purification of 4-hydroxybenzoic Acid and 4-hydroxybenzaldehyde from Laminaria japonica Aresch Using Commercial and Monolithic Sorbent in SPE Cartridge

Phenolic compounds are one of the major compounds in Laminaria japonica Aresch. Solid-phase extraction was used to separate the two phenolic compounds (4-hydroxybenzoic acid and 4-hydroxybenzaldehyde). A new monolithic sorbent was developed and used successfully as a special sorbent in a solid-phase extraction process. The effects on different SPE cartridges using silica, C₁₈, and monolithic were compared. Quantitative analysis was carried out using a C₁₈ analysis column (5 µm, 150 × 4.6 mm). Good linearity was obtained for the two targets, ranging from 0.5 to 100 µg mL^?1 (r ²  > 0.999), with relative standard deviations <4.7%.     

Neues vom P4Se4

New Results on P₄Se₄ Preparation of P₄Se₄ from the elements yields always the β-modification of P₄Se₄. α-P₄Se₄ is obtained only with selenium deficient samples. However, it is also observed, when P₄Se₃ is annealed and then extracted with CS₂. The insoluble part has the X-ray pattern of α-P₄Se₄. A reversible α-β transition is not observed. MAS-³¹P-NMR investigations on solid P₄Se₄ by Eckert et al. [2] reveal P₂Se_4/2 building units, which are, in view of our results, not dimer but linked to a polymeric network. Well-crystallized samples of β-P₄Se₄ are obtained only at measuring temperatures above 573 K. The structure is of monoclinic symmetry with the space group P2₁/n (a = 114.9, b = 729.0, c = 1211.0 pm, β = 120.80°). The reaction of α-P₄Se₃I₂ with bis-(trimethyltin)selenide in CS₂ at low temperature yields molecular α-P₄Se₄, which can be detected in solution by ³¹P-NMR spectroscopy. α-P₄Se₄ has D_2d-symmetry like α-P₄S₄. It polymerizes at higher temperature. α-P₄Se₃I(SeSnMe₃) and α-P₄Se₃(SeSnMe₃)₂ were observed in the course of this reaction, too. The analogous reaction of α-P₄Se₃I₂ with bis-(trimethyltin)sulfide leads to comparable results.     

The Oxidation and Reduction of 4-Formyl-and 4-Acetyl-3-Arylsydnones

A convenient method to prepare methyl 3-arylsydnonylacetate (I) from 4-acetyl-3-arylsydnone with thallium (III) nitrate by oxidative rearrangement was investigated. 4-Formyl-3-arylsydnones were reduced by sodium borohydride at room temperature to produce 4-hydroxymethyl-3-arylsydnones (II) in moderate yields (65%-85%), but the corresponding 3-aryl-4-sydnonecarboxaldehyde arylhydrazone (III) was obtained by the electrolytic reduction.     

Discussion of thermodynamic data obtained by adsorption gas chromatography of hydrocarbons on carbograph 4

Summary A new graphitized carbon black, Carbograph 4, with a specific surface area of 240 m² g⁻¹ was studied in terms of enthalpy, entropy and free energy of adsorption, determined by gas chromatographic method on a series of alkanes (C₂−C₆) and on benzene. The changes in the isosteric heat and entropy of adsorption when a non-polar stationary phase (squalane) was added to the adsorbent were also investigated. The data obtained are discussed and compared to those present in the literature for other graphitized carbon blacks. Some examples of separations obtained with Carbograph 4 are reported.     

NH4VO3在NH4H2PO4-H2O和(NH4)3PO4-H2O体系中的溶解度

采用等温溶解法测定了偏钒酸铵(NH₄VO₃)在NH₄H₂PO₄-H₂O和(NH₄)₃PO₄-H₂O体系中T = 298.15-328.15 K时的溶解度以及溶液的密度和pH值。结果表明, NH₄VO₃的溶解度随着(NH₄)₃PO₄或NH₄H₂PO₄溶液浓度的增大,先降低后升高,这是由于同离子效应、化学反应平衡及离子活度的共同作用。比较T = 298.15K时, NH₄VO₃分别在NH₄H₂PO₄-H₂O、(NH₄)₂HPO₄-H₂O和(NH₄)₃PO₄-H₂O体系中溶解度,发现在相同的磷酸盐浓度下, NH₄VO₃的溶解度在NH₄H₂PO₄-H₂O体系中最大,在(NH₄)₃PO₄-H₂O体系中居中,在(NH₄)₂HPO₄-H₂O体系中最小。进一步地,在T = 298.15 K和磷酸盐浓度C = 0.5 mol·kg^-1时,结合pH值和反应溶度积常数K_SP等计算三个体系中的平均离子活度系数(γ_±),发现γ_±值在(NH₄)₂HPO₄-H₂O体系中最大,在(NH₄)₃PO₄-H₂O体系中居中,在NH₄H₂PO₄-H₂O体系中最小,与溶解度规律一致。     

锂离子电池复合正极材料xLiFePO4·yLi3V2(PO4)3的复合机制

以FePO4·xH2O、V2O5、NH4H2PO4和Li2CO3为原料, 以乙二酸为还原剂, 通过湿化学还原-低温热处理方法制备出锂离子复合正极材料xLiFePO4·yLi3V2(PO4)3. X射线衍射(XRD)结果表明, 合成的材料中橄榄石结构的LiFePO4和单斜晶系的Li3V2(PO4)3两相共存; 从复合材料中LiFePO4、Li3V2(PO4)3相对于相同条件下制备的纯相LiFePO4和Li3V2(PO4)3的晶格常数变化以及结合高分辨透射电子显微镜(HRTEM)、能量散射X射线(EDAX)的结果可以看出, 在复合材料xLiFePO4·yLi3V2(PO4)3中存在部分V和Fe, 分别掺杂在LiFePO4和Li3V2(PO4)3中, 并形成固溶体; X射线光电子能谱(XPS)结果表明, Fe/V在复合材料中的价态与各自在LiFePO4和Li3V2(PO4)3中的价态保持一致, 分别为+2 和+3价. 充放电测试表明, 制备出的复合正极材料电化学性能明显优于单一的LiFePO4和Li3V2(PO4)3; 循环伏安测试表明, 复合正极材料具有优良的脱/嵌锂性能.     

沉淀法制备不同形貌和结构的纳米BiVO4

采用液相沉淀法，通过选择不同起始原料并控制反应温度和pH值，制备得到不同形貌和结构的纳米BiVO₄。采用X-射线衍射(XRD)、透射电子显微镜(TEM)和紫外-可见吸收光谱(UV-Vis)技术对产物进行分析表征。结果表明，采用NH₄VO₃作V源，室温下可直接制备得到结晶好的四方晶系硅酸锆型BiVO₄球形纳米颗粒，提高反应液pH值或升高温度，可得到单斜晶系白钨矿型BiVO₄，采用NaVO₃作为V源，室温下可直接得到单斜晶系白钨矿型片状BiVO₄。加入不同类型表面活性剂则得到不同形貌的BiVO₄。