Flammability and thermal behaviour of phosphorus-containing polyamides. Copolymers of poly(1,4-phenylene terephthalamide), poly(1,3-phenylene isophthalamide), poly(1,4-phenylene sebacylamide) and poly(1,3-phenylene sebacylamide)

Some flame retardant copolyamides derived from 1,4-phenylenediamine or 1,3-phenylenediamine and N,N′-bis[(dialkoxyphosphinyl)methyl]1,4-benzenediamine with terephthaloyl or isophthaloyl, or sebacoyl dichlorides, are reported. Thermal and thermo-oxidative stability were studied by means of TGA. The influence of chemical structure in enhancing thermo-oxidative resistance of copolyamides was established. In the case of sebacylamides the DSC thermograms were also obtained. The flammabilities of the copolymers were determined by means of the limiting oxygen index; in the case of sebacylamides, the limiting nitrous oxide index was also determined. Comparison of LN₂OI with the LOI in sebacylamides reveals that the action of the flame retardant groups affects mainly the condensed phase decomposition. This view is also supported from the new stage of decomposition revealed in the DTGA thermograms.     

The Synthesis and Characterization of Poly Oxy(2-methyl-1,3-phenylene) oxyisophthaloxyl-b-Oxy(2-methyl-1,3-phenylene)oxyterephthaloxyl

The syntheses and characterizations of poly[oxy(2-methyl-1,3-phenylene) oxyisophthaloyl-b-oxy (2-methyl-1,3-phenylene)oxy-terephthaloyl] and the corresponding homopolymers are described. The synthesis involves the coupling of dihydroxy-terminated homo-polymers with terephthaloyl chloride. The resulting block copoly-ester was characterized by infrared spectroscopy, proton and carbon- 13 nuclear magnetic resonance spectroscopy, solution viscosity, differential scanning calorimetry, and thermogravimetric analysis.     

Mesomorphic behaviour of 1,3-phenylene bis[4-(4-alkoxyphenyliminomethyl)benzoates] and related compounds

DSC and X-ray diffraction studies on a series of 1,3-phenylene bis[4-(4-alkoxyphenyliminomethyl)benzoates] are presented. The only mesophase exhibited by the methoxy to hexadecyloxy homologues is of the smectic C type. The reversal of the iminomethyl linkage reduces drastically the incidence of a mesophase; that is, only the first five homologous members exhibit a smectic C phase in the series of 1,3-phenylene bis[4-(4-alkoxybenzylideneamino)benzoates]. Almost all the members in the second series become nematogenic by the chloro substitution at the 4-position of the 1,3-phenylene moiety. In addition, a smectic C phase is observable for the ethoxy to pentyloxy and also the tetradecyloxy and hexadecyloxy members. The second chloro-substituent introduced to the 6-position of the same central ring eliminates completely the smectic C phase and enhances the nematic thermal stability.     

2,5-二辛氧基聚对苯的合成及表征

蓝色电致发光;2;5-二辛氧基聚对苯的合成及表征     

聚(2-甲氧基-5-壬氧基)对苯乙炔的合成及其电致发光性质

以对甲氧基苯酚和溴代正壬烷为原料,通过醚化、氯甲基化和脱氯化氢反应得到可溶性的聚（２－甲氧基－５－壬氧基）对苯乙炔,以其为发光层装配了聚合物单层电致发光器件,研究了它的电致发光和光致发光性质;电致发光器件具有良好的稳定性,其起亮电压为７Ｖ。聚合物的结构由ＩＲ、＾１Ｈ－ＮＭＲ及ＵＶ／Ｖｉｓ光谱得到确认。     

Synthesis and characterization of poly[2,5-bis(triethoxy)-1,4-phenylene vinylene]

The synthesis of a highly soluble, 2,5-disubstituted poly(p-phenylene vinylene) with pendant side chains containing ether groups was accomplished by a dehydrochlorination route. Specific interactions of the oxygen-containing side chains with the solvent are presumably responsible for the high solubility of the polymer, especially in protogenic solvents. The polymer microstructure was characterized by ¹H- and ¹³C-NMR. The polymer showed solvatochromic properties when dissolved in a variety of solvents. The relatively high molecular weight (M_n = 17,000) permitted the fabrication of free-standing films. The electrical conductivity of iodine-doped films was approximately 2 × 10^–2 S cm^–1. © 1995 John Wiley & Sons, Inc.     

Thermal degradation of aramids: Part I—Pyrolysis/gas chromatography/mass spectrometry of poly(1,3-phenylene isophthalamide) and poly(1,4-phenylene terephthalamide)

The thermal degradation reactions of poly(1,3-phenylene isophthalamide) or Nomex (I) and poly(1,4-phenylene terephthalamide) or Kevlar (II) aramids have been investigated in the temperature range 300–700°C by pyrolysis/gas chromatography/mass spectrometry. The initial degradation products below 400°C of (I) are carbon dioxide and water. At 400°C benzoic acid and 1,3-phenylenediamine are detected. Benzonitrile, aniline, benzanilide, N-(3-aminophenyl)benzamide as well as carbon monoxide and benzene are evolved in the range 430–450°C. The yields of these products increase rapidly in the range 450–550°C. Isophthalonitrile is observed at 475°C and hydrogen cyanide is detected above 550°C, as are other secondary products such as toluene, tolunitrile, biphenyl, 3-cyanobiphenyl and 3-aminobiphenyl. Pyrolysis of (II) below 500°C evolves only water and trace amounts of carbon dioxide. At 520–540°C the following degradation products have been detected: 1,4-phenylenediamine, benzonitrile, aniline, benzanilide and N-(4-aminophenyl)benzamide. These products as well as carbon dioxide and water increase appreciably between 550°C and 580°C; benzoic acid, terephthalonitrile, benzene and 4-cyanoaniline are also detected in this temperature range. Above 590°C, hydrogen, carbon monoxide, hydrogen cyanide, toluene, tolunitrile, biphenyl, 4-aminobiphenyl and 4-cyanobiphenyl are evolved. Degradation reactions consistent with the formation of these products, which involve initial heterolytic cleavage of the amide linkage for (I) and initial homolytic cleavage of the aromatic NH and amide bonds for (II), are described.     

Synthesis and antimicrobial activity of some novel 2-(substituted fluorobenzoylimino)-3-(substituted fluorophenyl)-4-methyl-1,3-thiazolines

The synthesis of several 2-(substituted fluorobenzoylimino)-3-(substituted fluorophenyl)-4-methyl-1,3-thiazolines (2a-t) was carried out by base-catalyzed cyclization of corresponding 1-(fluorobenzoyl)-3-(fluorophenyl)thioureas (1a-t) with 2-bromoacetone in aqueous medium. The structures of the synthesized compounds were confirmed by spectral and elemental analysis. All synthesized compounds were evaluated for in vitro antibacterial activity using Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis) and Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa). The minimum inhibitory concentration (MIC) was determined for the most active compounds. In vitro antifungal activity was also determined against the five fungal species (Rhizopus oryzae, Fusarium oxysporum, Aspergillus terreus, A. niger and A. fumigatus).     

双(1,4-二酰基氨基硫脲)化合物的合成

酰氨基硫脲及其相关化合物通常具有广泛的生物活性 ,如抗菌[1～ 3] ,抑制神经紧张[4] ,治疗血糖过低[5] ,植物生长调节[6～ 9] 等。迄今为止 ,鲜有关于双 (1 ,4 二酰基氨基硫脲 )合成的报道。为了考查该类化合物的生物活性 ,我们设计合成了一系列双 (1 ,4 二酰基氨基硫脲 )化合物 ,以下图所示的两条合成路线合成了该类化合物 :二酰氯 (1 )、异硫腈酸酰酯 (2 )等中间体可不经进一步纯化直接用于下一步反应。所生成的产物 3ａ 3ｆ、3′ｄ 3′ｇ经ＤＭＦ Ｈ2 Ｏ ＥｔＯＨ重结晶 ,产率达 81 %～ 98%。在合成化合物 (1 )时 ,对于一些用ＳＯＣｌ2 …     

Thermal degradation of aramids—Part II: Pyrolysis/gas chromatography/mass spectrometry of some model compounds of poly(1,3-phenylene isophthalamide) and poly(1,4-phenylene terephthalamide)

The thermal degradation reactions of seven aromatic amides which are structurally related to the commercial aramids Kevlar (poly(1,4-phenylene terephthalamide)) and Nomex (poly(1,3-phenylene isophthalamide) have been investigated in the temperature range 450 to 700°C by pyrolysis/gas chromatography/mass spectrometry. Benzanilide, N,N′-dibenzoyl-1,4-phenylenediamine, N,N′-dibenzoyl-1,3-phenylenediamine, N,N′-diphenylterephthalamide, N,N′-diphenylisophthalamide, N-(4-aminophenyl)-benzamide and N-(3-aminophenyl)benzamide all gave very low yields of carbon oxides and water. The structures of the higher molecular weight products were related to those of the parent compounds and their yields are presented quantitatively. The principal mechanism for thermal cleavage of the amide bonds in the N,N′-dibenzoylphenylenediamines is mainly heterolytic, while for the other compounds thermal cleavage of the amide bonds is homolytic. The relationship between the pyrolysis products of the model compounds and those of the corresponding aramids is discussed.     

Synthesis,antimicrobial and antioxidant activity of bis sulfonamide/carbamate derivatives of bis-(4-aminophenyl) methane

A series of new bis sulfonamide/carbamate derivatives of bis-(4-aminophenyl)methane 3 ( a–d )/ 5 ( a–f ) were synthesized from bis-(4-aminophenyl)methane ( 1 ) using various pharmacologically active sulfonyl chlorides 2 ( a–d ) and carbonochloridates 4 ( a–f ) in high yields. The structures of all the newly synthesized compounds were characterized by the Infrared spectroscopy, NMR (¹H and ¹³C), mass, and elemental analyses. Further, all the synthesized compounds were tested for the antioxidant activity by using 2, 2-diphenyl-1-picrylhydrazyl, NO, and H₂O₂ scavenging methods and antimicrobial activity. Most of the compounds exhibited good antioxidant and antimicrobial activities.     

1,2,3-Selenadiazoles as precursors to cyclopentadienylcobalt dithiolenes and 1,4-dithiins: molecular structures of bis(cycloocteno)-1,4-dithiin and bis(cycloocteno)-1,4-diselenin

Cycloocteno-1,2,3-selenadiazole ( 1 ) and cyclopenta-dienyldicarbonylcobalt ( 2 ) react in the presence of an excess of elemental sulfur to yield the dithiolene cyclopentadienyl(1,2-cyclooctenedithiolato)cobalt ( 3 ). Available evidence indicates that this reaction involves the intermediacy of a cobalt–alkyne complex. Compound 3 is the first example of a cyclopentadienylcobalt dithiolene bearing aliphatic substituents. Analogous reactions performed using only catalytic quantities of 2 provide high-yield syntheses of bis(cycloocteno)-1,4-dithiin ( 6 ) and bis(cycloocteno)-1,4-diselenin ( 7 ), whose structures have been determined by X-ray diffraction.     

Synthesis and antimicrobial activity of aminomethoxy-substituted 1-(ethylthio)heptanes

The Mannich condensation of 1-(ethylthio)heptane-2-ol, formaldehyde and secondary amines taken in equimolar amounts gives rise to new aminomethoxy-substituted 1-(ethylthio)heptanes in a yield of 70–77%. The structure of the synthesized compounds was proved by the elemental analysis, IR and ¹H NMR spectroscopy, and mass spectrometry. The compounds were tested as antimicrobial additives to lubricating oils. They were found to suppress effectively the activity of microorganisms.