超临界CO2中以PEG2000为模板制备TiO2/SiO2复合材料

超临界CO2;PEG;模板;TiO2/SiO2;复合材料     

纳米复合s2o2-8/sno2tio2催化α蒎烯异构反应

固体超强酸;s2o2-8/sno2tio2;纳米粒子;α-蒎烯;催化异构     

钨磷酸催化H2O2氧化降解壳聚糖

钨磷酸催化H2O2氧化降解壳聚糖;壳聚糖;钨磷酸;H2O2;催化降解     

CH3CF2O2与HO2自由基反应机理的理论研究

用密度泛函理论(DFT)的B3LYP方法，在6-311G、6-311+G(d)、6-311++G(d, p) 基组水平上研究了CH₃CF₂O₂与HO₂自由基反应机理. 结果表明, CH3CF₂O₂与HO₂自由基反应存在两条可行的通道. 通道CH3CF₂O₂＋HO₂→IM1→TS1→CH₃CF₂OOH＋O₂的活化能为77.21 kJ•mol^－1，活化能较低，为主要反应通道，其产物是O₂和CH₃CF₂OOH. 这与实验结果是一致的；而通道CH₃CF₂O₂＋HO₂→IM2→TS2→IM3→TS3→IM4＋IM5→IM4＋TS4→IM4＋OH＋O₂→TS5＋OH＋O₂→CH₃＋CF₂O＋OH＋O₂→CH₃OH＋CF₂O＋O₂的控制步骤活化能为93.42 kJ•mol^－1，其产物是CH₃OH、CF₂O和O₂. 结果表明这条通道也能发生，这与前人的实验结果一致.     

CO2在Na2Cr2O7溶液中的平衡溶解度模型

为研究重铬酸钠(Na₂Cr₂O₇)对CO₂溶解的影响, 本文在带有搅拌的气液相高压平衡釜内, 采用静态法测定了温度在313.2-333.2 K, 压力在0.1-1.9 MPa 范围内, 重铬酸钠浓度分别为0、0.361、0.650、0.901 mol·kg^-1 时, CO₂ 在Na₂Cr₂O₇溶液中的溶解度. 结果表明: (1) Na₂Cr₂O₇对CO₂ 的溶解有盐析效应; (2) CO₂ 在Na₂Cr₂O₇溶液中的溶解符合亨利定律, 并且CO₂溶解度是温度和Na₂Cr₂O₇浓度的函数, 且用改进的Setschenow方程和Peng-Robinson-Pitzer (PR-Pitzer)方程拟合了在此温度、压力及重铬酸钠浓度范围内的实验数据, 拟合效果较好, 并且其平均相对误差分别为4.24%和3.32%.     

C60Pd（Ph2POCH2CH2OPPh2）的合成与光电转化性能

C60Pd（Ph2POCH2CH2OPPh2）的合成与光电转化性能;富勒烯;钯配合物;光电性能     

Ti/RuO2-IrO2-SnO2-Sb2O5阳极在农村饮用水消毒中的应用

采用热分解法制备了一种新型高效析氯阳极Ti/RuO₂-IrO₂-SnO₂-Sb₂O₅,将其应用于农村饮用水消毒频繁停开、低电解液浓度的特殊工况下,并与Ti/RuO₂-SnO₂-Sb₂O₅、Ti/RuO₂-TiO₂、Ti/RuO₂-TiO₂-IrO₂三种析氯阳极进行性能对比。通过SEM、EDS、XRD等方法表征测试阳极表面形貌、元素及组成,考察了氯化钠浓度、电流密度、停开频率对阳极析氯效果和寿命的影响。研究发现,Ti/RuO₂-IrO₂-SnO₂-Sb₂O₅阳极活性强、稳定性高;阳极涂层各组分高度融合为固溶体,结构致密,稳定性强;在15 g·L^-1 NaCl、400 A·m^-2电流密度、20℃条件下,Ti/RuO₂-IrO₂-SnO₂-Sb₂O₅阳极电解的电流效率达到91.55%;频繁停开、强化电解条件下寿命达到231 h,是Ti/RuO₂-TiO₂阳极的77倍,预估在400 A·m^-2电流密度下能够使用20年。     

V2O5/γ-Al2O3和V2O5/SiO2负载型催化剂对异丁烷的催化脱氢性能

V2O5/γ-Al2O3和V2O5/SiO2负载型催化剂对异丁烷的催化脱氢性能;V2O5/γ-Al2O3; V2O5/SiO2; 异丁烷; 脱氢     

酶催化动力学光度法测定H2O2

H2O2能够氧化偶氮染料刚果红使之褪色,而模拟酶—血红蛋白对其具有催化作用。据此建立了一种以刚果红为指示剂的H2O2-刚果红-血红蛋白酶催化反应体系测定痕量H2O2的新方法。确定了反应的最佳条件,体系的酸度为pH10.7的NH3-NH4Cl缓冲溶液,最大吸收波长为497 nm。该法的线性范围为8.0×10^-8-8.0×10^-5mol/L,检出限为1.97×10^-9mol/L,表观摩尔吸光系数为4.6×10^4L.mol-1.cm^-1。该方法可用于雨水及消毒水中H2O2的测定。     

稀土固体超强酸SO2-4/ZrO2-SnO2-Nd2O3的制备及催化合成乙酸松油酯

稀土;固体超强酸;SO2-4/ZrO2-SnO2-Nd2O3;乙酸松油酯;酯化反应     

Syntheses of 2-hydroperoxy-and 2-hydroxy-2H-imidazoles

Oxidation of fully substituted imidazoles 1 by singlet oxygen gives in good yield fully substituted 2-hydroperoxy-2H-imidazoles 2 . Reduction of 2 by triphenylphosphine leads to 2-hydroxy-2H-irnidazoles 3 . Limitations of the methods are reported.     

Photocycloaddition of 2-Cyanocycloalk-2-Enones to 2, 3-Dimethylbut-2-Ene

Irradiation of 5,5-dimethyl-6-oxocyclohex- l-ene- l-carbonitrile ( 1 ) in the presence of 2,3-dimethylbut-2-ene afforded 3,3,4,4,7,7-hexamethyl-3,4,4a,5,6,7-hexahydroindeno[1,7-c,d]-],2-oxazole (3) in nearly quantitative yield. In contrast, 4,4-dimethyl-5-oxo-cyclopent-l-ene-l-carbonitrile ( 2 ) under the same conditions reacted not to a tricyclic isoxazole but to a 2:1 mixture of 3,3,6,6,7,7-hexamethyl-2-oxo-bicyclo[3.2.0]heptane-l-carbonitrile ( 4 ) and trans-3,3-dimethyl-2-oxo-5-(2,3-dimethylbut-3-en-2-yl)cyclopentane-l-carbonitrile ( 5 ), respectively.     

Thermal decomposition of Me3SnO2PCl2, Me2Sn(O2PCl2)2 and Ph3SnO2PCl2

TG and DTA studies on Me₃SnO₂PCl₂, Me₂Sn(O₂PCl₂)₂ and Ph₃SnO₂PCl₂ were carried out under dynamic argon atmosphere. The results show that the decomposition proceeds in different stages leading to the formation of Sn₃(PO₄)₂ as a stable product. This compound was characterized by IR spectroscopy. Decomposition schemes involving reductive elimination reactions were proposed.     

Crystal Structures of [Bu2Sn(O2PPh2)2], [Ph2Sn(O2PPh2)2], and [PhClSn(O2PPh2)OMe]2. Raman Spectra of [Ph2Sn(O2PPh2)2] and [PhClSn(O2PPh2)OMe]2

[(n‐Bu)₂Sn(O₂PPh₂)₂] ( 1 ), and [Ph₂Sn(O₂PPh₂)₂] ( 2 ) have been synthesized by the reactions of R₂SnCl₂ (R=n‐Bu, Ph) with HO₂PPh₂ in Methanol. From the reaction of Ph₂SnCl₂ with diphenylphosphinic acid a third product [PhClSn(O₂PPh₂)OMe]₂ ( 3 ) could be isolated. X‐ray diffraction studies show 1 to crystallize in the monoclinic space group P2₁/c with a = 1303.7(1) pm, b = 2286.9(2) pm, c = 1063.1(1) pm, β = 94.383(6)°, and Z = 4. 2 crystallizes triclinic in the space group , the cell parameters being a = 1293.2(2) pm, b = 1478.5(4) pm, c = 1507.2(3) pm, α = 98.86(3)°, β = 109.63(2)°, γ = 114.88(2)°, and Z = 2. Both compounds form arrays of eight‐membered rings (SnOPO)₂ linked at the tin atoms to form chains of infinite length. The dimer 3 consists of a like ring, in which the tin atoms are bridged by methoxo groups. It crystallizes triclinic in space group with a = 946.4(1) pm, b = 963.7(1) pm, c = 1174.2(1) pm, α = 82.495(6)°, β = 66.451(6)°, γ = 74.922(6)°, and Z = 1 for the dimer. The Raman spectra of 2 and 3 are given and discussed.     

Electrochemical study of (NEt4)2Cl2FeS2MoS2 and (NEt4)2Cl2FeS2MoS2FeCl2

Summary The ability of [MoS₄]^2–, anions to be used as ligands for transition metal ions has been widely demonstrated, especially with Fe²⁺. The present study has been restricted to linear complexes such as (NEt₄)₂ [Cl₂FeS₂MoS₂] and (NEt₄)₂[Cl₂FeS₂MoS₂FeCl₂]. Their electrochemical properties are described: upon electrochemical reduction, these compounds yield MoS₂, as a black precipitate, and an iron complex in solution, assumed to be [SFeCl₂]^2–. The electrochemical reduction goes through two electron transfers, coupled with the breakdown of the molecular skeleton: a DISPl and an ECE mechanism. Depending on the solvent, the following equilibrium may be observed: [Cl₄Fe₂MoS₄]^2–[Cl₂FeMoS₄]^2–+FeCl₂. The equilibrium constant, K_D, was evaluated by differential pulse polarography. K_D is tightly related to the donor number of the solvent.     

Homopolymerization of 2-alkyl- and 2-aryl-2-oxazolines

2-Aryl- and 2-alkyl-2-oxazolines have been polymerized to poly-(N-aroyl)aziridines and poly(N-acyl)aziridines, respectively, in the presence of boron trifluoride. The polymers obtained were glassy, light yellow resins with molecular weights ranging from 3500 to 7500 (35–50 oxazoline units per chain). The polymerization rates have been determined for several of these monomers. A polymerization mechanism is proposed.