Chlorination and oxidation of aromatic polyamides .2. Chlorination of some aromatic polyamides

The effects of chlorine on three kinds of aromatic polyamides: those not containing a substituent, those containing substituents, and those containing heterocyclic aromatic rings, were studied. The correlations between the chemical structures of polyamides and the reactivity to hypochlorous acid were examined by IR and C-13 solid-state NMR spectra before and after chlorination. It was found that the chlorination of polyamides depends not only on their chemical structures but also on chlorination conditions such as pH value and reaction time. Their response to chlorination corresponds to four types: ring-chlorination, no reaction, N-chlorination, and chain cleavage. (C) 1996 John Wiley & Sons, Inc.

Chlorination and oxidation of aromatic polyamides .1. Synthesis and characterization of some aromatic polyamides

The synthesis is described of some aromatic polyamides based on unsubstituted, and methyl-, carboxy-, and sulfo-substituted diamines by interfacial polycondensation. Some of them are crosslinked and some of them contain heterocyclic aromatic rings. Their chemical structures are characterized by IR and C-13 solid-state NMR spectra and the spectra are interpreted. (C) 1996 John Wiley & Sons, Inc.

AMPEROMETRIC DETECTION OF AMINO-ACIDS IN A FLOW-INJECTION SYSTEM WITH A NICKEL(II)-MODIFIED ELECTRODE WITH AN EASTMAN-AQ POLYMER FILM

Amperometic flow measurements were made at +0.55 V (vs. Ag/AgCl) in 0.1 mol l-1 KOH electrolyte with an Ni(II) chemically modified electrode (CME) with an Eastman-AQ polymer film. The use and characteristics of a Ni(II)-containing crystalline and polymer-modified electrode obtained by a double coating step as a detector for amino acids in a flow-injection system using reversed-phase liquid chromatography are described. The detection of these analytes is based on the higher oxidation state of nickel (NiOOH) controlled by the applied potential. The electroanalytical parameters and the detection current for a series of amines and amino acids were investigated. The use of such a CME in the flow-injection technique was found to be suitable in a solution at low pH. The linear range for glycine is 5 X 10(-6)-0.1 mol 1-1 with a detection limit of 1.0 X 10(-6) mol l-1. A 1 X 10(-4) mol 1-1 mixture of serine and tyrosine was also detected after separation on an Nucleosil C18 column.

PHASE-BEHAVIOR IN EPOXY-RESIN CONTAINING PHENOLPHTHALEIN POLY(ETHER ETHER SULFONE)

Phenolphthalein poly(ether ether sulphone) (PES-C) was found to be miscible with uncured bisphenol-A-type epoxy resin, i.e. diglycidyl ether of bisphenol A (DGEBA), as shown by the existence of a single glass transition temperature within the whole composition range. Miscibility between PES-C and DGEBA is considered to be due mainly to the entropy contribution. However, dynamic mechanical analysis (d.m.a.) and scanning electron microscopy (SEM) studies revealed that PES-C exhibits different miscibility with four cured epoxy resins (ER). The overall compatibility and the resulting morphology of the cured blends are dependent on the choice of cure agent. For the blends cured with amines (4,4'-diaminodiphenylmethane (DDM) and 4,4'-diaminodiphenylsulphone (DDS)), no phase separation occurs as indicated by either d.m.a. or SEM. However, for the blends cured with anhydrides (maleic anhydride (MA) and phthalic anhydride (PA)), both d.m.a. and SEM clearly show evidence of phase separation. SEM study shows that the two phases interact well in the MA-cured blend while the interface between the phases in the PA-cured blend is poorly bonded. The differences in the overall compatibility and the resulting morphology between the amine-cured and anhydride-cured systems have been discussed from the points of view of both thermodynamics and kinetics.

AMPEROMETRIC DETECTION OF CATECHOLAMINES WITH LIQUID-CHROMATOGRAPHY AT A NOVELLY CONSTRUCTED PRUSSIAN BLUE CHEMICALLY MODIFIED ELECTRODE

A novel Prussian blue chemically modified electrode (CME) was constructed and characterized for liquid chromatography electrochemical detection (LCEC) of catecholamines. Both anodic and cathodic peaks could be obtained by monitoring at constant applied potential at anodic and slightly cathodic potential ranges (0.3-0.7 and -0.2-0.1 V vs. SCE), respectively. When arranged in a series configuration, using the modified electrodes as generating and collecting detectors, extremely high effective collection efficiencies of 0.91 (for norepinephrine) and 0.58 (for dihydroxyphenylacetic acid) were achieved in dual-electrode LCEC for catecholamines; and a linear response range over 3 orders of magnitude and a detection limit of 10 pg were obtained with a downstream CME as the indicating detector.

EASTMAN-AQ/NIII MODIFIED ELECTRODE CHARACTERIZATION AND APPLICATION IN FLOW-INJECTION DETERMINATION OF CARBOHYDRATES AND AMINO-ACIDS

A novel Eastman-AQ/Ni(II) chemically modified electrode (CME) produced by "double coating step" deposition of a poly(ester sulphonic acid) polymer film and Ni2+-containing crystalline species onto glassy carbon instead of a metallic nickel electrode exhibited stable electrocatalytic oxidation of numerous alpha-hydrogen compounds including carbohydrates, amines and amino acids. In cyclic voltammetry, the electrocatalysis appeared with an irreversible anodic wave at +0.55 V (vs. Ag/AgCl). The CME was adapted for constant-potential amperometric detection of these compounds in flow injection analysis. Using the CME, the linear response concentration range was between 1.0 x 10(-5) and 5.0 x 10(-2) mol/l and the detection limit was 5.0 x 10(-6) mol/l for glucose. The stability of the CME was adequate for routine quantitative application.

Spectral changes of C-phycocyanin with different molar ratios of SPDP

Pure C-phycocyanin was prepared from Spirulina platensis using one-step anion-exchange chromatography. The C-PC obtained was with an absorption maximum at 620 nm and a fluorescence emission maximum at 640 nm when excited by 580 nm. SPDP is an excellent heterobifunctional crosslinker for thiolating amines. Different molar ratios of SPDP have remarkable influence on the absorption and fluorescence spectra of C-phycocyanin. The absorption maximum and fluorescence emission maximum both decreased and blue-shifted from 640 run to 630 nm as the molar ratios of SPDP increased. It was found that the molar ratios of SPDP to C-phycocyanin was not more than 100 was appropriate to being conjugated with other biomolecules from the absorption and fluorescence spectra of C-phycocyanin.

新型杂环化合物碳钢酸洗缓蚀剂的合成、评价及机理研究

缓蚀剂在金属防护工程中占有重要的地位，在国民经济建设中发挥着越来越重要的作用。从目前热力设备防腐及其他工业领域防腐情况来看，酸洗时使用缓蚀剂是一种行之有效、经济效益显著的防腐手段。虽然目前缓蚀剂从分子设计、合成路线与工艺，复配增效，应用性能等方面都取得了较大的发展，但是其理论进展仍远滞后于实践，对于不少缓蚀剂的缓蚀机理尚存争议，因此运用各种手段方法研究缓蚀剂的作用机理，发展和完善缓蚀剂理论，成为目前缓蚀剂研究领域的热门课题。本论文筛选或合成了三种类型十二种新型杂环化合物作为缓蚀剂，通过失重实验，电化学实验，量子化学计算及扫描电镜实验多种手段和方法测试了所选化合物在1mol/LHCl溶液中对碳钢的缓蚀性能，分析了它们对碳钢的缓蚀机理，从理论上探讨了缓蚀剂分子与金属表面的作用方式，总结归纳了分子结构与缓蚀效果之间的关系。 本论文中涉及的三类新型杂环化合物为：嘌呤类化合物，席夫碱-三唑类化合物和硫脲-三唑类化合物，针对不同类化合物的不同特点采用了不同的处理方法，研究的主要成果如下： 失重、电化学及扫描电镜实验结果表明，嘌呤类化合物对碳钢有较好的缓蚀效果和较高的缓蚀效率。针对嘌呤分子是平面型小分子的特点，结合实验现象及量子化学计算结果，推断了其吸附特点。在国内外缓蚀剂研究领域首次建立并使用了108个铁原子的碳钢表面模型，在此基础上，根据嘌呤类分子的吸附特点作了吸附曲线，证明嘌呤类分子的吸附机理为平面接近碳钢的物理吸附，嘌呤分子与碳钢表面的相互作用源于π-π超共轭作用。吸附曲线模型的创立和使用使得对缓蚀剂机理的研究不再仅仅局限于对缓蚀剂分子本身结构特点的分析与推测，而是可以在整个腐蚀体系的基础上对缓蚀剂分子在金属表面的作用机理进行研究，更重要的是，提供了一种在一定范围内从理论上筛选缓蚀剂的初步模型。 实验结果表明席夫碱-三唑类化合物对碳钢有很好的缓蚀效果以及很高的缓蚀效率，其中CMTT化合物，在10-3mol/L时对碳钢的缓蚀效率可达97%。针对席夫碱-三唑类化合物分子活性中心多，分子柔性刚性相结合的特点，量子化学计算中采用了富奎指数判断分子中起作用的活性吸附中心，推断了席夫碱-三唑类化合物的吸附为化学吸附。其机理为：通过巯基硫原子提供电子与碳钢表面铁原子成键，而碳钢表面多余的负电荷反馈至席夫碱的碳氮双键形成反馈键。新型席夫碱-三唑类化合物作为缓蚀剂的研究不但提供了新型高效无毒的酸洗缓蚀剂，而且碳氮双键与杂环的结合在提高了化合物缓蚀效率的前提下，还针对杂环化合物水溶性差的缺点提供了一种提高水溶性的解决方法，为更多新型化合物用于缓蚀剂领域提供了可行之道。 硫脲-三唑类化合物同样对碳钢有很好的缓蚀效果以及很高的缓蚀效率，尤其是TBU化合物，在10-3mol/L时对碳钢的缓蚀效率高达98%。针对硫脲-三唑类化合物分子缓蚀过程中硫原子的突出贡献，量子化学计算中将硫原子连接在碳钢表面上，然后对整个体系进行了结构优化，从理论上证明了该类化合物的吸附机理为：通过巯基硫原子提供电子与碳钢表面铁原子形成配位键，而硫脲-三唑类化合物分子中以苯环为主的共轭体系则以π-π超共轭作用覆盖在碳钢表面，是以化学作用为主物理-化学作用共存的吸附方式。而且在研究该类化合物的吸附机理中，发现了分子中小基团的立体位阻因素对化合物的缓蚀性能造成很大影响，目前关于此类的报道非常罕见。 值得一提的是，在各类缓蚀剂交流阻抗谱的测试与处理过程中，发现缓蚀剂分子的吸附过程对阻抗谱图有很大影响，本论文中采用了两种等效电路图相结合的方法对阻抗谱图进行了处理，体现了吸附过程的影响，得到更好的拟和结果。 新型杂环化合物作为缓蚀剂的研究，不但提供了多种具有潜在应用前景的高效低毒的新型酸洗缓蚀剂，对目前缓蚀剂领域存在的部分问题提出了解决方案，更重要的是，将新的模型和方法运用于对缓蚀剂机理的研究分析中，为缓蚀剂的筛选提供了一种新的理论模型，为新型缓蚀剂分子的设计合成提供了一定的科学依据，对缓蚀剂理论的发展与完善起到了一定的促进作用。

Synthesis and Bioactivity of Novel Benzisothiazolone Derivatives as Potential Microbiocides

Novel microbiocides 2-(hydroxymethyl)benzo[d)isothiazol-3(2H)-one (7) and (3-oxobenzo[d]isothiazol-2(3H)-yl)methyl benzencarboxylates (11a-c) were synthesized in good yields, and their structures were characterized by means of H-1 NMR, MS, and elemental analysis. The new compounds were tested preliminarily in laboratory assays against the aquicolous bacteria including Escherichia coli, Staphyloccus aurueus, Vibrio alginolyticus, Aeromonas hydrophila, and Bacillus subtilis. The results show all the synthesized compounds have good antimicrobial activity. The antimicrobial activity of all the tested compounds against all test bacteria is >96.6% at the concentration of 10(-2) mg mL(-1). These compounds can be further developed for effective microbiocides in the future.

Synthesis of titanium silicalites in different template systems and their catalytic performance

Titanium silicalites have been synthesized in the TPABr+ammonia, TPABr+hexanediamine, TPABr+ethylenediamine, TPABr+diethylamine, TPABr+TEAOH, TPABr+n-butylamine, TPABr+TBAOH and TBAOH+n-butylamine systems. As-synthesized titanium silicalites were characterized by XRD, IR and C-13 CP MAS NMR. Catalytic performance in epoxidation of propylene and template effect was investigated. It has been shown that both TPABr and TBAOH serve as templating agent in TPABr+TBAOH system. But in other systems, when there is enough TPABr, organic amines or ammoniums only act as the bases. TEAOH or n-butylamine can take the role of template when less TPABr is added. It indicates that the ability of organic amines or ammoniums to direct the Pentasil structure decreases as follows: TPA(+)>TBA(+)>TEA(+)>n-butylamine. Catalysts exhibiting good performance in epoxidation of propylene can be attained using TPABr as the template and ammonia, n-butylamine, diethylamine, hexanediamine or TBAOH as bases. (C) 1999 Elsevier Science B.V. All rights reserved.