氯自由基介导的光催化芳基醚C(sp^(3))−H氧化生成酯

饱和的碳氢键氧化是合成化学和化学工业中一类重要的化学反应.然而,饱和C(sp^(3))−H键离解能(BDEs)较高、极性较弱,导致了底物难以活化和催化转化效率较低等问题.在过去的几十年,C(sp^(3))−H键的定向活化转化取得了重要的进展.其中,关于C(sp^(3))−H键催化氧化的研究主要涉及一些键能低的、预活化的C−H键,包括苄基型、亚甲基型、脂肪族X−CH_(2)(X=O,N)和甲苯等,含有未活化C(sp^(3))−H键的复杂化合物的选择性氧化仍具有挑战性.例如,芳基醚C(sp^(3))−H键功能化通常采用计量的过氧化物氧化剂,或者通过单电子氧化和碱促进的去质子化进一步构建C−C/C−N键,产物选择性较低,也带来了一些不利的环境影响.因此,有必要开发高效、温和的芳基醚C(sp^(3))−H键选择氧化方法,并将其应用于有机合成和药物开发.近年来,光催化C(sp^(3))−H键氧化因其操作简便、氧化还原中性等优点,已发展成为一种有用且多样的催化研究工具.本文发展了一种利用氧气作为氧化剂,在可见光驱动下选择性地将芳基醚C(sp^(3))−H键氧化成为甲酸苯酯类产物的新方法.使用Mes-10-phenyl-Acr^(+)−BF_(4)^(-)光催化剂,高效活化多种氯源(如盐酸、无机氯盐和有机氯化物)得到氯自由基,由于其具有较高的氧化能力(+2.03 V vs.SCE)和对氢原子的亲和力,能够通过氢原子转移过程活化芳基醚C(sp^(3))−键,攫取氢自由基得到相应的烷基碳自由基(•CH_(2)OPh)中间体,进一步被分子氧选择氧化得到酯类目标产物.研究结果表明,多种链状芳基醚和不同取代(如给电子基和吸电子基)芳基醚均可发生氧化反应,高收率地合成了一系列官能团丰富的甲酸苯酯类化合物.本文方法具有反应条件温和、操作简单、官能团耐受性好以及可规模化放大等优点,并且少量的水对反应没有明显影响.机理实验研究结果表明,芳基醚C(sp^(3))−H键的断裂是反应过程的决速步骤.紫外可见吸收光谱结果表明,氯离子与催化剂之间的相互作用强于底物,并且自由基捕获实验证实反应体系中存在氯自由基和烷基碳自由基物种,表明反应经历自由基路径.此外,电子顺磁共振测试结果表明,反应过程中存在单线态氧物种,可能是激发态的光催化剂直接与氧气发生能量转移得到;同位素实验(18O)揭示了甲酸苯酯类化合物氧的来源.综上,本文实现了温和条件下光催化芳基醚C(sp^(3))−H键选择氧化反应,高收率合成了一系列甲酸苯酯类化合物.该方法避免了化学计量的过氧化物和碱等添加剂的使用以及底物的过度氧化,阐明了催化反应机制,为其他醚类化合物的C(sp^(3))−H键氧化功能化提供了新思路,为后续化学合成和药物开发提供了参考和启示.

脂肪醇聚氧乙烯醚AEO_(3)和双癸基二甲基氯化铵复配及性能

表面活性剂分子的复配体系往往比单一表面活性剂体系表现出更好的物化性能,因此得到广泛使用。将双癸基二甲基氯化铵DEQ和脂肪醇聚氧乙烯醚AEO_(3)分别按照不同质量比进行复配,详细考察了不同复配体系临界胶束浓度(cmc)、耐碱性、润湿性、乳化性、发泡性的变化情况。结果显示:复配体系表现出良好的协同效应。当复配比为1∶3时,cmc最低为1.46×10^(-5)mol/L,表面张力r_(cmc)达到最低值29.65 mN/m,表面吸附量Γ_(max)为3.01×10^(-10) mol/m^(2);当复配比为2∶1时,起泡性能优异,泡沫丰富,且稳泡性能达到88%,此对比单一的非离子表面活性剂AEO_(3)具有很大的改善;同时润湿性6.35 s明显高于非离子表面活性剂AEO_(3)。

Preparation of Ni(HCO_3)_2 and its catalytic performance in synthesis of benzoin ethyl ether

Ni（HCO3）2 with unique phase and high crystallinity was synthesized with urea hydrolysis. The as-prepared samples were well characterized in detail. N2 adsorption and desorption result manifests a high surface area of 99.03 m2/g with a pore size of 7.8 nm. Scanning electron microscopy （SEM） and particle size distribution reveal that the diameters of the formed pellets are uniform. Thermogravimetry （TG） analysis result shows that 500 ℃ could be the appropriate temperature for converting Ni（HCO3）2 precursors into NiO via a thermal decomposition process. CO2 and NH3 temperature-programmed desorption results show that Ni（HCO3）2 has explicit acid-base sites. Transmission electron microscopy （TEM） results vividly indicate that the pellets are aggregated by hexagonal platelets and possess porous structures. Ni（HCO3）2 can efficiently catalyze the one-step synthesis of benzoin ethyl ether from benzaldehyde and ethanol, with the conversion ofbenzaldehyde up to 57.5% and nearly 100% selectivity of benzoin ethyl ether.

Effects of ZrO_2 on the Performance of CuO-ZnO-Al_2O_3/HZSM-5 Catalyst for Dimethyl Ether Synthesis from CO_2 Hydrogenation

A series of composite catalysts were prepared by the wet mixing method, and the mass ratio of CuO-ZnO-Al2O3-ZrO2 component to HZSM-5 zeolite （molar ratio of SiO2 to Al2O3 being 25） was 2：1. The CuO-ZnO-Al2O3-ZrO2 （CuO/ZnO/Al2O3=3/6/1 by weight） component was prepared by a modified ＇two-step＇ co-precipitation method. The effects of ZrO2 on the performance of CuO-ZnO-Al2O3/HZSMo5 catalyst for dimethyl ether synthesis from CO2 hydrogenation were investigated. It was found that ZrO2 improved the properties of CuO-ZnO-Al2O3/HZSM-5 as a structural promoter.

Synthesis of nanocrystalline γ-Al_2O_3 by sol-gel and precipitation methods for methanol dehydration to dimethyl ether

The capability of sol-gel and conventional precipitation techniques for the synthesis of nanocrystalline γ-alumina was investigated. These catalysts were used for vapor-phase dehydration of methanol to dimethyl ether in a fixed-bed reactor under the same operating conditions （T = 300 ？C, P = 1 bar, LHSV = 2.8, 11.7, 26.1 h？1） and characterized by means of N2 adsorption-desorption, NH3-TPD, XRD, TGA and SEM techniques. According to the experimental results, the catalysts prepared using sol-gel method in non-aqueous medium showed better performance compared with those prepared by other methods.

ELECTROCHEMICAL COPOLYMERIZATION OF 3-(4-FLUOROPHENYL)THIOPHENE AND 3-METHYLTHIOPHENE IN BORON TRIFLUORIDE DIETHYL ETHERATE

The copolymer poly（3-（4-fluorophenyl）thiophene-co-3-methylthiophene） was successfully prepared from mixtures of 3-（4-fluorophenyl）thiophene （FPT） and 3-methylthiophene （MET） via electrochemical oxidation in boron trifluoride diethyl etherate （BFEE） and its mixed electrolytes with acetonitrile （ACN）. The influence of monomer concentration ratios on the copolymerization was investigated by using linear sweep voltammetry and cyclic voltammetry. The structure and morphology of these copolymer films were elucidated by UV-Vis, infrared spectroscopy, elemental analysis, thermal analysis and scanning electron microscopy （SEM）, respectively. The results showed that the molar ratio of FPT and MeT units, when copolymer was electrodeposited from feed ratio of FPT：MeT = 1：2, was about 1.08：1. In addition, the introduction of ACN into BFEE has little effect on the properties of as-formed copolymers.

Catalytic Oxidation of Dimethyl Ether to Dimethoxymethane over Cs Modified H_3PW_(12)O_(40)/SiO_2 Catalysts

The attractive utilization route for one-step catalytic oxidation of dimethyl ether to dimethoxymethane was successfully carried out over the H3PW12O40（40%）/SiO2 catalyst, modified by Cs, K, Ni, and V. The Cs modification of H3PW12O40（40%）/SiO2 gave the most promising result of 20% dimethyl ether conversion and 34.8% dimethoxymethane selectivity. Dimethoxymethane could be synthe- sized via methoxy groups decomposed from dimethyl ether through the synergistic effect between the acid sites and the redox sites of Cs modified H3PW12O40（40%）/SiO2.

Synthesis and antibacterial activity of brominated 2′(4′)-nitro-3-hydroxy diphenyl ethers

Eight new brominated 2＇（4＇）-nitro-3-hydroxy diphenyl ethers have been designed and synthesized. The structures of new compounds were confirmed by ^1H NMR, IR and HRMS. The bioactivity tests showed that these compounds possessed antibacterial activities against the tested bacteria. These new compounds cannot be transformed into dioxins when they were manufactured and used.

Enhanced catalytic performance for direct synthesis of dimethyl ether from syngas over a La_2O_3 modified Cu-ZrO_2/γ-Al_2O_3 hybrid catalyst

A series of hybrid catalysts were made by physically mixing Cu-ZrO2 and γ-A12O3, for former it was modified with different loadings of La2O3 prepared by co-precipitation method. The catalysts were characterized by BET, XRD, N2O-adsorption, EXAFS, H2-TPR, NH3-TPD techniques and evaluated in the synthesis of dimethyl ether from syngas. The results show that La2O3 promoted catalysts displayed a significantly better catalytic performance compared with Cu-ZrO2#y-A12O3 catalyst in CO conversion and DME selectivity, and the optimum catalytic activity was obtained when the content of La2O3 was 12 wt%. The characterizations reveal that high copper dispersion, facile reducibility of copper particles and appropriate amount of acidic sites are responsible for the superior catalytic performance.

BF₃.OEt₂-Mediated Benzylation of Arenes and Heteroarenes with Benzyl Ether Derivatives

An efficient BF3.OEt2-promoted benzylation of arenes and heteroarenes with various benzyl ether derivatives has been developed. This method provided alternative access to valuable diarylmethane in good yields under mild conditions via an easy work-up procedure.

STUDIES ON RARE EARTH COMPLEXES WITH CROWN ETHERS ⅩⅧ——Synthesis,Characterization and Crystal Structure of[Sc(NO_3)_3(H_2O)_2]·(15-Crown-5)

The single crystal of the complex [Sc(NO_3)_3(H_2O)_2]·(15C5) has been prepared in acetonitrile.The new complex has been characterized by elemental analysis,IR spectra,solubility and molar conductance measurements.The structure of the complex is determined by single crystal X-ray diffraction analysis.

SPECTRAL STUDY ON A NEW 3d_z^2 TYPE COPPER(Ⅱ)COMPLEX OF PHENOLIC POLYMERIC CROWN ETHER

ESR and IR measurements have been carried out for a copper(Ⅱ)complex of phenolic polymeric crown ether,As a result,the triplet ESR spectrum(S=1)of 3d_z2 ground state copper(Ⅱ)ions was first observed for the powder sample.It indicated that there existed intramolecular spin-spin interaction betweeen 3d_Z2 ground state copper(Ⅱ)and copper(Ⅱ)ions.In this binuclear triplet cluster,the axial ligntion of one water molecule in a sandwich position to two adjacent copper(Ⅱ) ions was also confirmed by IR spectra,All things considered,a possible structure for the complex was proposed.

Chemospecific and Regioselective Ethereal Methyl-Oxygen Bond Cleavage Behavior of Aroylated Dimethoxynaphthalenes by Combined Action of AlCl₃and Aroyl Group

AlCl3-mediated cleavage of ethereal methyl–oxygen bond in aroylated 2,7-dimethoxynaphthalene compounds proceeds chemospecifically and regioselectively. The ethereal bond at the β(2)-position of 1-monoaroylated 2,7-dimethoxynaphthalene is cleaved readily and predominantly against the β(7)-position, whereas scission of β-ethereal bonds of 1,8-diaroylated 2,7-dimethoxynaphthalene hardly undergoes like the non-aroylated mother frame compound of 2,7-dimethoxynaphthalene.

A 3D Nickel(Ⅱ) Complex Constructed by Bis(2-dimethylaminoethyl)Ether:Solvothermal Synthesis,Crystal Structure and Catalytic Properties

Treatment of bis（2-dimethylaminoethyl） ether（BDMAE） with nickel acetate afforded a novel 3D nickel（Ⅱ） complex [Ni（BDMAE）（H2O）3·（CH3COO）2·（H2O）2] under solvothermal conditions. Its crystal structure was characterized by elemental analysis, IR spectrum, PXRD and single-crystal X-ray diffraction analysis. The complex belongs to the orthorhombic system, space group C2221 with a=8.823（2）, b=13.932（3）, c=17.563（4） , V=2158.9（8） 3, Z=4, C（12）H（36）N2NiO（10）, Mr=427.14, Dc=1.314 g/cm3, F（000）=920 and μ=0.944 mm（-1）. Single-crystal X-ray diffraction reveals that the mononuclear nickel（Ⅱ） ion is six-coordinated to one oxygen, two nitrogen atoms of the BDMAE ligand and three oxygen atoms of coordinated water molecules. The complex exhibits a 3D supramolecular structure through a variety of intermolecular and intramolecular hydrogen bonding interactions. In addition, the complex has been investigated for catalytic properties towards the Henry reaction of nitromethane with p-nitrobenzaldehyde, and the results indicated that the 1-p-nitrophenyl-2-nitroethanol product was obtained in excellent yield under optimum conditions with the complex as the catalyst.

Two Nickel(Ⅱ) Complexes Constructed by Novel Bis(3-methoxy-2-pyridyl)ether-6,6′-dicarboxylic Acid Ligand:Lattice Water Control of Structure

Under given conditions, two complexes of [Ni（H20）2BEDA]·2H2O 1 and [Ni（Py）2- BEDA]·6H2O 2 （BEDA = bis（3-methoxy-2-pyridyl）ether-6,6′-dicarboxylic acid） have been synthesized and characterized by elemental analysis and X-ray single-crystal diffraction. Crystal data for 1： C14H18NiN2O11, monoelinic C2/c, a = 14.3844（17）, b = 12.9900（15）, c = 9.6309（11） A, β = 104.3350（10）°, V= 1743.5（4） A3, Z = 4, Dc= 1.711 g/cm^3, F（000） = 928, μ = 1.179 mm^-1, Mr= 449.01, the final R = 0.0228 and wR = 0.0625. Crystal data for 2： C24H32NiN4O13, triclinic P1, a = 9.423（2）, b = 11.863（3）, c = 13.089（3） A, α = 91.511（3）, β = 92.465（3）, γ = 100.696（2）°, V = 1435.6（6） A^3, Z = 2, Dc= 1.488 g/cm^3, F（000） = 672, μ = 0.748 mm^-1, Mr= 643.25, the final R = 0.0400 and wR = 0.0975. Interestingly, in the two complexes, lattice water molecules dominate its crystal structures. Therefore, extensive intermolecular hydrogen bonds assemble 1 and 2 into 2D extended sheets and a 3D open framework, respectively. Furthermore, water molecules present in 2 are associated to form water clusters.

二甲醚/聚甲氧基二甲醚-3简化机理的构建及验证

采用基于误差的直接关系图法(DRGEP)、敏感性分析法以及同分异构聚合法对二甲醚/聚甲氧基二甲醚-3(DME/DMM3)的联合详细化学反应机理进行简化,最终构建了一个包括65个组分和308个反应方程式的DME/DMM3简化化学动力学机理.为了验证其可靠性,分别用二甲醚(DME)和聚甲氧基二甲醚-3(DMM3)详细机理及试验数据与DME/DMM3简化机理计算得到的着火延迟、层流火焰燃烧速度和组分摩尔分数等进行了比较,并分析了DME/DMM3反应路径.最后验证了柴油机转速为1600r/min,当量比为0.18和0.34,燃料DME与DMM3体积配比为1∶9时的仿真与试验的缸内压力和放热率以及CO、CO_(2)、NO_(x)和HC排放物.结果表明:该DME/DMM3简化机理的着火延迟时间、层流火焰燃烧速度及射流搅拌反应器(JSR)中组分摩尔分数、缸内压力、放热率以及CO、CO_(2)、NO_(x)和HC排放物与试验值吻合良好,验证了简化机理的可靠性.

AgNO_(3)/NaY吸附纯化HFE-347的研究

通过等体积浸渍法成功制备了AgNO_(3)/NaY吸附剂,并对其进行XRD、N2吸-脱附和ICP-AES等表征。将制备的AgNO_(3)/NaY应用于1,1,2,2-四氟乙基-2,2,2-三氟乙基醚(HFE-347)中的杂质1,1,1-三氟乙基-1,1,2-三氟乙烯基醚的吸附脱除研究。结果表明,4%-AgNO_(3)/NaY可将HFE-347中1,1,1-三氟乙基-1,1,2-三氟乙烯基醚的浓度由920 mg/kg降至82 mg/kg,去杂率高达91%,为HFE-347在高端领域的应用提供了技术支撑。

Formation of Hybrid Ring Structure of Cyanurate/Isocyanurate in the Reaction be-tween 2,4,6-Tris(4-Phenyl-Phenoxy)-1, 3,5-Triazine and Phenyl Glycidyl Ether

Reaction products of 2,4,6-tris(4-phenyl-phenoxy)-1,3,5-triazine derived from 4-phenylphenol cyanate ester and phenyl glycidyl ether were analyzed. In addition to an isocyanurate compound and an oxazolidone compound which were well known as reaction products of cyanate esters and epoxy resins, compounds with hybrid ring structure of cyanurate/isocyanurate were determined. Gibbs free energies of the compound having hybrid ring structure of cyanurate/isocyanurate with two isocyanurate moiety were found to be lower than that of the compound with cyanurate ring structure through calculations. Calculation data supported the existence of hybrid ring structure of cy-anurate/isocyanurate. It was revealed that isomerization from cyanurate to isocyanurate occurs via hybrid ring structure of cyanurate/isocyanurate in the reaction of aryl cyanurate and epoxy.

异阿玛瑞卡诺A甲醚、异阿玛瑞卡宁A甲醚和(±)┐3┐甲氧基┐4,9,9┐三羟基苯并二氧六环木脂素的合成

异阿玛瑞卡诺Ａ（７）［ＩｓｏａｍｅｒｉｃａｎｏｌＡ（７）］，异阿玛瑞卡宁Ａ（８）［ＩｓｏａｍｅｒｉｃａｎｉｎＡ（８）］及（±）－３－甲氧基－４，９，９－三羟基苯并二氧六环木脂素（９）［（±）－３－ｍｅｔｈｏｘｙ－３，７－ｅ－ｐｏｘｙ－８，...

4,4'—双(3-氨基苯氧基)二苯甲酮及其聚醚醚酮酰亚胺的合成

在N,N—二甲基甲酰胺和甲苯的混合溶剂体系中,4,4'—二氟二苯甲酮(DFBP)与3—氨基苯酚(3AP)在无水碳酸钾的作用下发生化学反应,合成得到了4,4'—双(3-氨基苯氧基)二苯甲酮(443BAPOBP)单体。通过熔点测试、高效注注液相色谱(HPLC)、傅立叶红外(FT-IR)以及元素分析对443BAPOBP进行了表征,并且在N,N-二甲基乙酰胺溶剂中,443BAPOBP与均苯四甲酸二酐(PMDA)聚合成得到了新型的聚醚醚酮酰亚胺(PEEKI)树脂及其薄膜。