Nachweis von ω-Aminocarbonsäuren und Carbonylverbindungen in thermooxidativ abgebautem Polycaprolactam

After oxidation and subsequent hydrolysis homologous series of alkyl amines and ω-amino carboxylic acids were proved to be further degradation products of polycaprolactam. The formation of these substances cannot be explained by an attack on the N-vicinal methylene group which is the most reactive site of this polymer. Considering the low and nearly equal amount of nitrogen containing degradation products a statistical attack on the remaining methylene groups takes place besides the preferred N-vicinal reaction. The CO-vicinal site is not particularly activated. The formation of likewise isolated substances with carbonyl groups cannot be explained by a uniform mechanism.     

Oxidative Kupplung CH-acider Verbindungen mit p-Phenylendiaminen. I. Einfluß von Substituenten an CH-aciden Verbindungen auf die Farbkupplung

Oxidative Couping of CH-acid Compounds with p-Phenylenediamines. I. Influence of Substituents in CH-acid Compounds on the Colour Coupling 1-Phenyl-pyrazolin-5-ones and 1-naphtholes with different substituents are characterized by the rate constants of the oxidative colour coupling with diethyl-p-phenylene diamine. The effects of leaving groups in the active methylene or methine position of the rate determining step are analysed. Furthermore the influence of substituents in different positions of the molecules on pK_a values, rate constants and properties of the formed dyes is compared.     

Metal–polymer nanocomposites produced by the melt‐compounding interaction of an aliphatic polyamide with metal particles

Composites prepared at 200°C by the melt compounding of copolymer polyamide 6/66 and ferric chloride, ferric oxalate, cupric chloride, cupric formiate, cupric acetate, Cr‐carbonyl, Mo‐carbonyl, or W‐carbonyl have been studied. The solution stability and aggregation suppression for nanoparticles in a polyamide can be explained by the formation of stable polymer–metal complexes. The nitrogen atoms of amide and amine groups of polymers serve as ligands for the coordination compounds that form. The dynamic viscosity of the solutions suggests that Cr‐carbonyl forms mostly intermolecular complexes, whereas ferric oxalate, ferric chloride, cupric formiate, cupric acetate, cupric chloride, Cr‐carbonyl, Mo‐carbonyl, and W‐carbonyl form intramolecular complexes. The critical concentrations for metal‐containing compounds at which a dispersion rises to nanodimensions without aggregating in the polymer matrix under the experimental conditions are 0.024 wt % for ferric oxalate, 0.12 wt % for ferric chloride, 0.08 wt % for cupric formiate, 0.096 wt % for cupric acetate, and 0.19 wt % for cupric chloride. Metal carbonyls undergo dispersion (with their concentration up to 5 wt %) in polyamide 6/66 without aggregating into larger formations. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Oxidative Kupplung CH-acider Verbindungen mit p-Phenylendiaminen. IV. Massenspektrometrische Untersuchungen an 4-substituierten 1-Hydroxy-2-naphthoesäure-Derivaten

Oxidative Coupling of CH-acid Compounds with p-Phenylenediamines. IV. Mass Spectrometric Investigations of 4-Substituted 1-Hydroxy-2-naphthoic-acid Derivatives. Mass spectrometric fragmentations of 4-substituted 1-hydroxy-N-3′, 5′-(dimethoxy-carbonyl)phenyl-2-naphthalene carboxamides and derivatives of 1-hydroxy-2-naphthoic acid and 4-bromo-1-hydroxy-2-naphthoic acid have been determined. All compounds undergo a characteristic fragmentation. The most important primary process is amide cleavage and hydrogen rearrangement. The relation of the primary fragments which compete for the charge depends on the substituents of the active methylene group and of the amide. The mass spectra permit determination of structure, purity and stability of the substituted colour couplers.     

1H-NMR spectroscopic investigation of polyamide fibers grafted with vinyl monomers

Nuclear magnetic resonance spectroscopy was used to investigate the position of active centers in polyamide fibers subjected to graft copolymerization with poly(acrylic acid), poly(itaconic acid), and poly(2-vinylpyridine) initiated by thermal oxidation in air. As a result, structural changes in polyamide fibers brought about by oxidation and subsequent grafting of the above mentioned polymers were observed. It was estimated that the generation of active centers that initiate the copolymerization take place at the nitrogen atoms of the amide groups in the polyamide chain. This was confirmed by the broadening of the absorption band for the methylone group adjacent to the nitrogen as well as by the absence of a new absorption band for the methine groups, assuming that the generation of active centers and grafting would take place at the carbon atom of the methylene group in position α to the amide group. © 1996 John Wiley & Sons, Inc.     

Die polymerisation von lactamen, 86. Verzweigung der autopolymerisationsprodukte von 8-octanlactam

Assumed branching of polymer chains of poly(8-octane lactam) was proved from the study of solution properties of polymers prepared under the conditions of autopolymerization in the temperature range 240–260°C. The amidine structures in the polymer chains which were found out by hydrazinolysis are not in relation to the branching in the full extent.     

金属络合型聚丙烯腈抗菌消臭纤维的结构与性能

利用含多官能团聚丙烯腈纤维和不同金属离子反应 ,制备了一种金属络合型聚丙烯腈抗菌消臭纤维 ,并测定了其抗菌消臭性能。结果表明 :该纤维不仅含有多种含氮、含氧、杂环等官能团 ,且形成金属络合物 ,对不同菌类具备优异的杀菌活性 ,并具有抗菌谱广 ,作用时间持久和效率高等特点。     

Recent trends in the chemistry of 2-aminobenzothiazoles

The chemistry of 2-aminobenzothiazoles has gained increased interest in both synthetic organic chemistry and biological fields, since a large number of developments in the use of such compounds, covering the literature up to 2007, seem to be of considerable value. The present review presents their synthetic methods and chemical reactions. The reactions are subdivided in groups that cover reactions at the amino substituent without touching the benzene ring and reactions which involve both nitrogen in the formal amidine system to give fused heterocyclic systems. Most imaginable reaction types have been successfully applied and used, as many of the synthesized compounds exhibit interesting biological activity in various fields.     

Miniaturized method for separation and quantification of nitrogen species in petroleum distillates

The properties of nitrogen compounds are a subject of interest to petroleum refiners due to the detrimental role, these compounds play in catalyst deactivation and product stability. It is thought that basic nitrogen is a major contributor to these phenomena, and therefore identification and quantification of nitrogen species by type would be of great importance.A practical miniaturized method for quantitative separation of nitrogen compounds by type in petroleum distillates is described. Solid phase extraction methodology was used to concentrate the nitrogen compounds and to separate them further into neutral and basic types. The basic nitrogen compounds could not be fully recovered, while full recovery was achieved for the neutral nitrogen types. The amount of basic nitrogen was calculated by difference, and boiling point distribution profiles were produced. For identification of nitrogen compounds in separated fractions, a combined GC-MS/AED method with retention time locking was used. Carbazole and its substituted derivatives methyl, dimethyl, and trimethylcarbazoles were identified in the product from fluid catalytic cracking.     

Synthesis and Characterization of Polyamides Derived From Cyano-Containing 1,4-Bis(4-aminophenoxy)benzene Monomers

Summary A series of potentially electroactive aromatic-aliphatic polyamides based upon 3,6-bis(2-cyano-4-aminophenoxy)phthalonitrile (1) was synthesized in N,N-dimethylacetamide to yield polymers with intrinsic viscosities of 0.66-1.04 dL/g. One polyamide was synthesized using 1,4-bis(2-cyano-4-aminophenoxy)benzene (2) to compare to 1. There appears to be an odd-even effect of methylene spacer length upon the mechanical properties and glass transition temperature, with an even number of methylene groups yielding the larger values. Thermogravimetric analysis in air and nitrogen showed that these polymers had similar 5% weight losses in both atmospheres, which indicated that oxygen is not involved in the initial degradation of these polymers.     

Ammonium Formate-Pd/C as a New Reducing System for 1,2,4-Oxadiazoles. Synthesis of Guanidine Derivatives and Reductive Rearrangement to Quinazolin-4-Ones with Potential Anti-Diabetic Activity

1,2,4-Oxadiazole is a heterocycle with wide reactivity and many useful applications. The reactive O-N bond is usually reduced using molecular hydrogen to obtain amidine derivatives. NH₄CO₂H-Pd/C is here demonstrated as a new system for the O-N reduction, allowing us to obtain differently substituted acylamidine, acylguanidine and diacylguanidine derivatives. The proposed system is also effective for the achievement of a reductive rearrangement of 5-(2′-aminophenyl)-1,2,4-oxadiazoles into 1-alkylquinazolin-4(1H)-ones. The alkaloid glycosine was also obtained with this method. The obtained compounds were preliminarily tested for their biological activity in terms of their cytotoxicity, induced oxidative stress, α-glucosidase and DPP4 inhibition, showing potential application as anti-diabetics.     

普罗托品类生物碱的合成及其杀虫活性

[目的]对小果博落回中分离的普罗托品、隐品碱和别隐品碱中的十元氮杂环和苯环进行结构修饰,合成了17种普罗托品类生物碱,在确认其结构的基础上考查其体外杀虫活性。[方法]首先,采用ESI-MS、1H NMR和13C NMR等波谱技术对目标化合物的结构进行表征;接着,以伊维菌素为阳性对照,采用浸虫法分别测定了目标化合物在0.5、1 g/L时对兔痒螨和小麦红蜘蛛的体外杀灭活性。[结果]大多数化合物对兔痒螨和小麦红蜘蛛均显示了一定程度的杀灭活性。其中,待测物1的活性最佳,其对兔痒螨的致死率达71.7%;对小麦红蜘蛛的致死率为60.0%,校正致死率达57.1%。[结论]对目标化合物的结构及其杀虫活性进行分析,发现向十元氮杂环引入C=C键可显著提高该类化合物的杀螨活性;向13位引入羰基可提高它们杀灭小麦红蜘蛛的活性。为普罗托品类杀虫剂的研发提供了一定的理论依据。     

Über den thermischen Abbau von Polyamiden der Nylon-Reihe

Several aliphatic polyamides (nylon-7, nylon-12, nylon-4, nylon-6,6, nylon-6,10, nylon-4,10, nylon-11,6, nylon-12,12) have been investigated in a mass spectrometer. Cyclic oligomers, which evaporate in the high vacuum of the ion source at temperatures below 200°C can be detected without previous isolation. The start of a thermal decomposition can be observed via the total ion current at temperatures above 350°C. Under those conditions polyactams are degraded by ring-chain equilibration into cyclic oligomers, whereas the favoured decomposition of polyamides of dicarboxylic acids and diamines is a cis elimination and the cleavage of the amide bond. With an increasing content of methylene groups these mechanisms also occur in polylactams. Mass spectra recorded of each polyamide at 170°C and ca. 400°C are characteristic and can be used for a fast identification and differentiation.     

Synthesis and X-ray structure analysis of 2-[cyano(aryl)-methylene]-imidazolidines, -hexahydropyrimidines,and -hexahydro-1H-1,3-diazepines

2-[Cyano(aryl)methylene]-imidazolidines ( 7 ), -hexahydropyrimidines ( 8 ) and -hexahydro-1 H -1,3-diazepines ( 9 ) were synthesized by the reaction of (dimethylthiomethylene)-phenylacetonitriles ( 6 ) with ethylenediamine, 1,3-diaminopropane and 1,4-diaminobutane, respectively. These molecules were designed to study the tautomeric equilibrium between the ketene aminal form and the amidine form by changing the substituent on the para position of the phenyl group. But all the products obtained were the ketene aminals. Because the phenyl group was twisted over 30° from the plane containing the two nitrogen atoms and the double bond as shown by the crystal structure of 7a, 8a and 9a , the substituents had no effect on the equilibrium.     

Cerium–initiated Polymerisation of Some Vinyl Compounds in Polyamide Fibres

Several vinyl polymers have been grafted onto nylon 6. 6 with ceric salts as initiators. Some factors influencing the polymerisation of acrylic acid have been examined in detail, and evidence obtained that the products are true graft copolymers. Grafting of both 2–vinylpyridine and 4–vinylpyridine is slow from solutions in dilute sulphuric acid or nitric acid, but rapid from perchloric acid. Slow diffusion of initiator into polyamide fibres is apparently responsible for a non–uniform distribution of polymer sometimes observed. Nylon 6. 6 is oxidised slowly, but extensively, by cerie salts and the reaction is accelerated by oxygen. Analyses of the products are consistent with oxidation at methylene groups adjacent to the amide nitrogen rather than at amine end–groups. A paradox, thatdinitrophenylation renders nylon less susceptible to grafting of poly(acrylic acid), but not to oxidation by eerie salts, is tentatively explained. The surface electrical resistivity of nylon fabric is not lowered by grafted polyacrylamide or its N–alkyl derivatives, whilst salts of poly(acrylic acid) and poly(vinylpyridines) impart only a temporary lowering. Poly(1–rnethyl–4–vinylpyridinium) perchlorate was more permanently effective. Attempts to polymerise some potentially antistatic betaine–type monomers in nylon were unsuccessful.     

有机添加剂SEED在聚酰胺6改性中的应用

在己内酰胺水解聚合时加入一定量的有机添加剂N，N′-二(2.2，6.6-四甲基-4-哌啶基)-1.3-苯二酰胺，合成出含有添加剂SEED的改性聚酰胺6树脂，研究了改性聚酰胺6的流变性、热稳定性及染色性。实验表明：当SEED添加量为0．2％时，聚酰胺6熔体表观粘度随剪切速率的升高而下降的趋势变慢，熔体加工稳定性提高；与空白试样相比，改性聚酰胺6的初始热分解温度提高约3℃，高温(170℃、190℃)老化1h后纤维的断裂强度保留率可达80％以上，热稳定性改善；且改性树脂的端氨基含量可高达45mmol／kg，为空白试样的1．7倍，纤维的酸性染料染色上染率明显提高。改性聚酰胺6稳定性、染色性的改善，是有机添加剂SEED中特有的芳胺基和受阻哌啶基结构综合作用的结果。     

Effect of Polyamide 66 on the Mechanical and Thermal Properties of Post-Industrial Waste Polyamide 6

Post-industrial waste (PIW) polyamide 6 is successfully used in lieu of commercial virgin polyamide 6, in several automotive applications. The presence of polyamide 66 in the final formulation may affect the mechanical and thermal properties of the PIW polyamide 6 materials. Using unreinforced polyamide 6 from PIW and commercial sources, it was found that the addition of polyamide 66 (below 10 wt.%) lowered the crystallization rate and crystallinity level of all polyamide 6 materials. The thermal and mechanical properties of glass fiber (GF) reinforced PIW polyamide 6 compounds with and without polyamide 66 were also studied. Differential scanning calorimetry (DSC) showed that reinforced materials without polyamide 66 had a higher level of crystallinity. Furthermore, dynamic mechanical analysis (DMA) showed that reinforced compounds without polyamide 66 also had a faster storage modulus buildup immediately after injection molding. Reinforced PIW polyamide 6 compounds without polyamide 66 also exhibited higher tensile and higher vibration weld strengths as well as a thicker heat affected zone (HAZ) than those with polyamide 66, leading to the conclusion that polyamide 66 had a detrimental effect on crystallinity level and consequently on the mechanical properties of GF-reinforced PIW polyamide 6 materials.     

剑麻基抗菌纤维的制备及其结构与性能

在 0 .2 m ol/L 的硝酸溶液中 ,以 0 .0 5 mol/L 高锰酸钾为引发剂先合成剑麻接枝聚丙烯腈纤维。然后用水合肼进行功能化改性 ,合成了一种新型的天然剑麻基抗菌纤维 ,并测定了它的抗菌消臭性能。结果表明 :剑麻纤维经接枝聚丙烯腈改性功能化后 ,其表面含有多种含氮、含氧、杂环等官能团 ,对不同菌类具备优异的杀菌活性 ,并且具有广谱抗菌 ,作用时间持久和效率高等特点。     

Mass spectra of the picolinyl ester derivatives of some non-methylene-interrupted octadecadienoic acids

The electron-impact mass spectra of the picolinyl ester derivatives of 5,12-, 6,12-, 7,12-, 8,12-, 6,10- and 6,11-octadecadienoic acids were obtained. There are features in each that are diagnostic of the position of the terminal double bond, although doubt could exist, with unknown compounds, about the position of the proximal double bond if authentic spectra were not available for comparison purposes. There appear to be features in the spectra of isomers with two and three methylene groups between double bonds that are of value for characterization purposes.     

Inhibition of nitrogen compounds on the hydrodesulfurization of substituted dibenzothiophenes in light cycle oil

The influence of nitrogen compounds on the hydrodesulfurization (HDS) activities of a series of substituted dibenzothiophenes in light cycle oil (LCO) was studied over a NiMo/Al₂O₃ commercial catalyst. Three types of light cycle oil with nitrogen compounds of different concentrations and chemical natures were used as feed—an original fluid catalytic cracking light cycle oil (LCO), LCO with most of its basic nitrogen removed, and an ultra-low nitrogen LCO. Experiments were conducted in a fixed-bed microreactor at a total pressure of 70 atm, temperatures between 330 and 400 °C, and liquid hourly space velocities (LHSV) in the range of 1.0 to 3.5 h⁻¹. The inhibition effects of nitrogen compounds on the HDS reactivity of the three sulfur groups—total sulfur, hard sulfur, easy sulfur—and 14 specific mono-, di- and tri-alkyl substituted dibenzothiophenes were investigated. The results showed that the HDS rate significantly increased using ultra-low nitrogen LCO. Pseudo first-order rate constants were estimated for the 14 mono-, di- and tri-alkyl substituted dibenzothiophenes. The HDS rates could be classified into three groups based on the position of the substituents. It was found that 4 and 6 substituted dibenzothiophenes had the lowest HDS rates. The HDS rate of the 14 substituted dibenzothiophenes were all increased when the ultra-low nitrogen feed was used. The improvement was greater for 4 and 6 substituted dibenzothiophenes than for those with one of the substituents at either the 4 or 6 positions. This finding indicates that the hydrogenation route is more strongly suppressed than hydrogenolysis route by nitrogen compounds since the hydrogenation route is believed to be the predominant reaction pathway for 4 and 6 alkyl-substituted dibenzothiophenes.