三氧杂环己烷的电化学特性

直接氧化一些有机小分子(如甲醇[1~9]和乙醇[10~14]等)的直接氧化燃料电池作为一种对环境友好的能源越来越引起人们的关注.三氧杂环己烷作为一种可再生的能源,可以从地球上存在的大量天然气中得到,来源广泛,价格低廉.三氧杂环己烷反应的基本结构如Scheme 1所示,相对乙醇而言,三氧杂环己烷不存在任何碳碳键,反应更易进行.目前广泛研究的直接氧化燃料电池均采用液体甲醇和S chem e 1 S tru ctu re of tr ioxane乙醇等作燃料,液体燃料的存储运输存在一定的安全隐患,一旦泄漏发生危险,后果非常严重,而三氧杂环己烷作为一种固体,可以有效地避免上述问题的发生,利于安全的储存和运输.Narayanan等[13]研究了三氧杂环己烷在Pt,Pt-Sn和Pt-Ru电极上的电化学行为及其在燃料电池中的应用.本文研究了三氧杂环己烷在不同浓度、不同温度和不同酸度时于光滑铂电极上的电化学行为,初步分析了三氧杂环己烷的反应机理.1实验部分1.1试剂与仪器采用Potentiostat/GalvanostatModel 273A恒电位仪(美国Princeton Applied Research公司),在传统的三...

Microstructure analysis of nylon 66 by WAXD and SAXS

The analysis of the small angle X-ray scattering (SAXS) data was based upon particle characteristic function, one-dimensional electron-density correlation function and particle distribution function. The microstructure of nylon 66 with different degrees of crystallinity was studied by means of X-ray scattering method. The radius of gyration R-g, the Porod radius R-p, the thickness of crystalline region L-c the thickness of non-crystalline region L-n, the thickness of interphase region d(tr), the long period L, the semiaxises of particles (a, a, b), the distribution of the particle sizes and the scattering invariant were calculated. The results indicate that there was a significant interphase region between the crystalline region and the non-crystalline region. and its content (W-t,W-x) should not be neglected in comparison with that of crystalline region W-c,W-x. The morphology of nylon 66 prepared by isothermal crystallization at a high temperature was mainly a lamellar structure, while the spherical crystals dominated in the quenched sample. The size of the particles in the quenched sample was smaller than that of those in the isothermally crystallized sample. and the distribution of the particle sizes in the isothermally crystallized sample was wider.

Size-affected crystallization of trans-1,4-polybutadiene

By using different catalyst systems, two trans-1,4-polybutadiene (TPBD) samples with different tr trans-content and molecular weight were synthesized. The phase transition of two samples from monoclinic form to hexagonal phase was revealed by differential calorimeter scanning and X-ray, respectively. The small-angle X-ray scattering measurements showed the remarkable discrepancy of phase transition and melting point between the two samples was attributed to the different lamellar thickness of crystals: The crystals with different crystalline morphology and lamellar thickness were developed by casting different concentration TPBD solutions. Transmission electron microscopy morphology observations proved that annealing the specimen at the temperature above the phase transition point for different times resulted in the different lamellae thickening of monoclinic form. It means that annealing the TPBD in its hexagonal phase will also slightly favor the increase of both the phase transition temperature and melting point of hexagonal phase. (C) 2001 Elsevier Science Ltd. All rights reserved.

Novel sodium sulfonate-functionalized poly(ether ether ketone)s derived from 4,4 '-thiodiphenol

Novel sodium sulfonate-functionalized poly(ether ether ketone)s derived from 4,4'-thiodiphenol with degree of sulfonation up to 2.0 were synthesized by nucleophilic polycondensation of various amount of 5,5 '-carbonylbis(2-fluorobenzenesulfonate) (1) and 4,4'-difluorobenzophenone (2) with 4,4'-thiodipheno (3). Component and structure of the polymers were confirmed by TR, NMR and elemental analysis. Wide angle X-ray diffraction patterns indicated an amorphous structure of the polymers. All the polymers showed excellent thermal stability and poor solubility in water. (C) 2001 Elsevier Science Ltd. All rights reserved.

拉米呋定合成研究进展

综述了拉米呋定 ( Lamivudine)全合成研究进展。

Preparation and characterization of DBSA doped polyaniline thin films

Stable monolayer of the polyaniline(PAn) doped with dodecyl benzenesulfonic acid(DBSA) can form on the pure water surface. The multilayer ultrathin film can be successfully deposited by Langmuir-Blodgett(LB) technique onto CaF2 substrate. The limiting mean molecular area and collapse pressure observed are 0.066 nm(2) and 35 mN m(-1), respectively. The multilayer LB film and casting film were all characterized by TR and UV-Vis-NIR spectroscopies.

Influence of interface on radiation effects of crystalline polymer - radiation effects on polyamide-1010 containing BMI

Aimed at saving the radiation dose required to crosslinking the polyamid-1010, BMI/PA1010 systems containing different amounts of difunctional crosslinking agent N,N'-bis-maleimide-4,4'-biphenyl methane (BMI) were prepared and the structure changes at the crystallographic and supermolecular levels before and after irradiation were studied by using WAXD, SAXS, and DSC techniques. It was found that by incorporation of BMI the microcrystal size L-100 is lowered due to the formation of hydrogen bond between the carbonyl oxygen of BMI and the amide hydrogen of PA1010 in the hydrogen bonded plane, and the overall crystallinity W-c is also decreased. The presence of BMI causes the crystal lamella thickness d(c) to decrease and greatly thickens the transition zone d(tr) between the crystalline and amorphous regions. As for the irradiated specimen, the maximum increments in the L-100 and W-c against dose curves decrease with BMI content, and the interception point D-i, at which the L-100 and W-c curves intercept their respective horizontal line of L-100/L-100(0) and W-c/W-c(0)=1, shift to lower dose with an increase in BMI concentration. In addition. the mechanism of the radiation chemical reactions in the three different phases under the action of BMI are discussed with special focus on the interface region. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.

Synthesis of a photochromic bisphenoxynaphthacenequinone compound by two-step method

A new photochromic bisphenoxynaphthacenequinone compound, 6,6'-[1-methylethylidenebis (4,1-phenyleneoxy)]bis (5,12-naphthacenequinone) (1), was synthesized by a two-step method, i.e., synthesis of 6-[4-(2-(4-hydroxyphenyl)isopropyl) phenoxy]-5, 12-naphthacenequinone (2) from 6-chloro-5, 12-naphthacenequinone (3) and bisphenol-A, and a further reaction of compound 2 in DMF/acetone mixed solvent in the presence of anhydrous potassium carbonate and potassium iodide. The crude product is obtained in a precipitate form and can easily be purified by recrystallization. The solvent composition has marked influence on the yield of the precipitated crude product in the second step.

Studies on uniaxially drawn poly(vinylidene fluoride) films

Poly(vinylidene fluoride) (PVDF), under certain conditions, shows a crystal transition between the alpha (TGT (G) over bar) and beta (TTT) forms, where T, G, and (G) over bar, respectively, denote trans, gauche, and minus gauche. We investigated the mechanism of this crystal transition by FT-TR and X-ray diffraction, which yielded consistent results. We also carried out differential scanning calorimeter experiments.

A preliminary study on chemistry of phenoxynaphthacenequinones

A preliminary study on the chemistry of 6-phenoxy-5,12-naphthacenesuinone derivatives was reported, It was found that the main product was 6-(N,N-dimethylamino)-5,12-naphthacenequinone when a reaction of 6-chloro-5,12-naphthacenequinone with 4-hydroxyazobenzenes in DMF was carried out under certain reaction conditions. When the reaction of 6-[4-(4-hydroxyphenyl)isopropyl)phenoxy]-5, 12-naphthacenequinone and epichlorohydrin was carried out in an acetone/DMF(V/V=2/1) mixed solvent and in the presence of K2CO3 and KI, a new phenoxynaphthacenequinone derivative,6,6'-[1-methylethylidenebis(4,1-phenyleneoxy)]bis(5,12-naphthacenequinone), was obtained.

Structure-property relationship of phenoxynaphthacenequinones and their relatives

Like 6-phenoxy-5,12-naphthacenequinone (1), 6-[4-(2-( 8-hydroxyphenyl) isopropyl)phenoxy]-5, 12-naphthacenequinone (2) and 6-naphthyloxynaphthacenequinone (6) showed normal photochromism, The relative initial rates of trans to ana photoconversion were in the order: 1, 100; 2, 37; 6, 21, 6-[4-(Phenylazo)phenoxyl-5,12-naphthacenequinone (3), 6-[4-(p-ethoxyphenylazo) phenoxy]-5,12-naphthacenequinone (4), 6-[4-(p-nitrophenylazo)phenoxy]-5,12-naph cenequinone (5) had only slight W-induced photochromism for the phenoxynaphthacenequinone photochrome. 6-(2-Nitrosonaphthyloxy)-5,12-naphthacenequinone (7) exhibited no photochromism and underwent irreversible photoreaction.

SYNTHESIS OF POLYBUTADIENE MACROINITIATOR AND POLYBUTADIENE/POLYACRYLAMIDE BLOCK-COPOLYMERS

An azo-group containing polybutadiene macroinitiator was prepared by Pinner synthesis and characterized by IR, NMR, GPC, viscosity and elemental measurements. The macroinitiator was further use to polymerize acrylamide (AAm) in benzene to form polybutadiene/polyacrylamide (PBD/PAAm) block copolymers. High conversion of AAm was obtained over a wide range of monomer/macroinitiator ratios. The PBD/PAAm block copolymers were found to have excellent solvent resistance.

LIQUID-CRYSTALLINE POLYSURFACTANT

A new kind of amphiphilic polymer(PAMC(16)B) has been synthesized where the amphiphilic moiety is attached as a side chain via the hydrophilic end to the polymer backbone. DSC, POM, and WAXD study revealed that the polysurfactant formed thermotropic liquid crystalline phase. The liquid crystalline domains appeared after annealed at the melt for a period of time, and evolved with annealing. It was indicated that the thermodynamic effect played a significant role on the self-aggregation of hydrophobic ends, so as to form liquid crystalline structure. X-ray investigation suggested that the mesophase structure could be described as smectic with lamellar type of packing, in which alkyl tails aggregated to form layer, A model of supermolecular structure was given.

APPLICATION OF POLYBUTADIENE-BASED POLYMERIC SURFACTANTS IN LIQUID MEMBRANE SEPARATION

New polybutadiene-based surfactants (LYF) were synthesized by sulfonation of liquid polybutadiene with acetal sulfate at an elevated temperature, and their properties in a liquid surfactant membrane (LSM) separation process were examined by comparison with the two polyisobutylene-based surfactants ECA4360 and EM301. It was found that LYF surfactants had satisfactory overall properties as regards stability, swelling, and demulsification Of the W/O emulsion in the cases of both acidic and caustic internal aqueous phases.

SYNTHESIS AND PHOTOCHROMISM IN SOLUTION OF PHENOXYNAPHTHACENEQUINONE DERIVATIVES

Two new phenoxynaphthacenequinone derivatives, 6-[4-(2-(4-hydroxyphenyl)isopropyl)phenoxy] -5,12-naphthacenequinone (7) and 6-[4-(potassium sulfophenylazo)phenoxy]-5,12-naphthacenequinone (8), were synthesized, and their photochromism in solution was investigated and compared with that of 6-phenoxy-5,12-naphthacenequinone (1). On the basis of the spectral data and the selective irreversible reaction of ammonia with the colored phenoxy-ana-naphthacenequinone, the concentrations of the ana forms at the photostationary state (PSS), achieved by 365 nm UV irradiation, and the molar extinction coefficients of the pure ana forms at 481-482 nm of compounds 1, 7 and 8 in dimethylsulfoxide (DMSO) were found to be 83 mol.% and 1.70x10(4) mol(-1) dm(3) cm(-1), 82 mol.% and 1.62x10(4) mol(-1) dm(3) cm(-1) and 16 mol.% and approximately 1.34x10(4) mol(-1) dm(3) cm(-1) respectively; the absorption spectra of the colored ana forms of 7 and 1 in DMSO were estimated; the rate;constants of photoconversion induced by 365 nm light were obtained. The results show the strong effect of the structure of the phenoxynaphthacenequinones on their photochromism in solution. In addition to DMSO solution, compound 7 exhibited normal photochromism in toluene, benzene, chloroform and a DMSO-ethanol mixed solvent, but not in dimethylformamide (DMF) in which a photoinduced reaction occurred between 7 and DMF or impurities.