Introduction of the trihydrated hydronium ion concept into the dyeing mechanism of nylon with polybasic dyes

Summary The adsorption isotherms of polybasic acid dyes (two dibasic dyes and two tribasic dyes) on three kinds of nylon fibers at constant p_H (3.5) have been determined at 90 °C. The nylon fibers, Nylon-1, –2 and –3 had amino group analyses of 25, 54 and 95 meq/kg, respectively. From the adsorption isotherms the saturation value of the dyes on each nylon fiber was calculated. For the dibasic dyes, the saturation value on each nylon fiber was very near the amino group content of the fiber. This indicates that these dyes are adsorbed stoicheiometrically on each nylon fiber. For the tribasic dyes, the stoichiometric behavior was observed only on Nylon-3. A crude calculation was made of the distance between amino groups in each nylon fiber. It was seen from the scale model of the dyes that the distance of sulfonic acid groups in the dye molecule is much smaller than that of amino groups in the fiber. The H₉O₄ ⁺ bridge hypothesis was proposed in order to explain how a polybasic dye can physically saturate fixed sites.

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Zusammenfassung Die Adsorptionsisothermen von mehrbasischen Säurefarbstoffen (zwei dibasische Farbstoffe und zwei tribasische Farbstoffe) an Nylonfasern von dreierlei Art bei konstantem p_H (3.5) wurden bei 90 °C bestimmt. Die Nylonfasern Nylon-1, –2 und –3 ergeben bei Aminogruppenanalysen Werte von 25, 54 und 95 mäqu/kg. Aus Adsorptionsisothermen wurden die Sättigungswerte für diese Farbstoffe auf jeder Art Nylonfaser berechnet. Für die dibasischen Farbstoffe wurden die Sättigungswerte auf jeder Nylonfaser sehr nahe dem Aminogehalt in der Faser gefunden. Das zeigt, daß diese Farbstoffe auf den Nylonfasern stoichiometrisch adsorbiert werden. Bei den tribasischen Farbstoffen wurde das stöchiometrische Verhalten nur auf Nylon-3 gefunden. Die Abstände zwischen den Aminogruppen in jeder Nylonfaserart wurde näherungsweise berechnet. Aus dem Molekülmodell des Farbstoffes stellt sich heraus, daß der Abstand zwischen den Sulfonsäuregruppen im Farbstoffmolekül viel kürzer als der zwischen irgendwelchen Aminogruppen in der Faser ist. Deshalb wird eine H₉O₄ ⁺-Brücken-Hypothese vorgeschlagen, um zu klären, wie ein mehrbasischer Farbstoff feste Plätze physikalisch absättigen kann.

     

Aryl vinyl sulfones as thiol protective group

Phenyl vinyl sulfone and p-tolyl isobutenyl sulfone are convenient reagents for protecting SH groups via the Michaël adduct. Protection and deprotection can be achieved in high yields under mild basic conditions, in protic or aprotic solvents.     

Structural elucidation of a methylenation reagent of esters: synthesis and reactivity of a dinuclear titanium(iii) methylene complex

Transmetallation of a zinc methylene complex [ZnI(tmeda)]₂(μ-CH₂) with a titanium(iii) chloride [TiCl₃(tmeda)(thf)] produced a titanium methylene complex. The X-ray diffraction study displayed a dinuclear methylene structure [TiCl(tmeda)]₂(μ-CH₂)(μ-Cl)₂. Treatment of an ester with the titanium methylene complex resulted in methylenation of the ester carbonyl to form a vinyl ether. The titanium methylene complex also reacted with a terminal olefin, resulting in olefin-metathesis and olefin-homologation. Cyclopropanation by methylene transfer from the titanium methylene proceeded by use of a 1,3-diene. The mechanistic study of the cyclopropanation reaction by the density functional theory calculations was also reported.

Transmetallation of a zinc methylene complex [ZnI(tmeda)]₂(μ-CH₂) with a titanium(iii) chloride [TiCl₃(tmeda)(thf)] produced a titanium methylene complex.     

Diffusion of Rod-Like Polypeptides in the Liquid Crystalline and Isotropic Phases as Studied by High Field-Gradient NMR Spectroscopy

In this lecture the measurements and analyses of the isotropic and anisotropic diffusion coefficients(D) of rod-like polypeptide such as poly(γ-L-glutamate)(PLG) with n-alkyl side chains, of which the main chain takes the α-helical conformation, as a function of the main chain length in the thermotropic and lyotropic liquid crystalline phases over a wide range of temperatures from 30 to 80°C by means of pulse high field-gradient spin echo ¹H NMR method have been introduced. In the anisotropic diffusion, the D_∥ value in direction parallel to the α-helical chain axis is found to be much larger than the D_⊥ value in direction perpendicular to the α-helical chain axis. The diffusion process is followed by the Kirkwood theory. Further, it is described that the diffusion in the nematic liquid crystalline phase is much slower than that in the isotropic phase.     

Coprecipitation Behavior of Some Metals with Chitosan and Their Determination by Graphite Furnace Atomic Absorption Spectrometry

Chitosan is derived from chitin by deacetylation. Chitosan forms a complex with metal ions and is soluble an organic acid. The metal ions were concentrated in the precipitates of chitosan when the sample solution containing metal ions was adjusted to neutral after the chitosan solution was added. These properties are applied to the preconcentration of metal ions in water samples and their determination by graphite furnace atomic absorption spectrometry. Metal ions,such as ruthenium, indium, vanadium, strontium,rhodium were collected in the chitosan precipitates.     

基于地对空观测光谱的大气CO2柱浓度反演分析

基于地对空高光谱观测获取大气CO₂柱浓度(大气中CO₂的垂直总含量)数据是验证和改进卫星高光谱观测反演CO₂浓度的重要数据源之一,而目前在中国还没有基于地面光谱观测进行大气CO₂柱浓度反演研究的报告。利用光谱分析仪与太阳跟踪仪等构成的地面观测系统在中国内蒙古锡林郭勒草原进行了地对空高光谱观测,基于高光谱观测数据反演了大气CO₂柱浓度。在基于1.6 μm大气CO₂的光谱吸收特征进行CO₂浓度反演过程中,评价分析了观测光谱的波长漂移和气象参数对大气CO₂柱浓度反演精度的影响。结果显示观测期间平均大气CO₂柱浓度为390.9 μg·mL-1。波长的漂移将会导致反演浓度值整体偏低;波长漂移从-0.012～0.042 nm范围时,将会导致1 μg·mL-1以上的偏差。同时,研究发现光谱透过率在6 357～6 358,6 360～6 361和6 363～6 364 cm-1谱段敏感于气象参数的变化。对比利用与光谱观测同时和非同时观测的气象参数进行的浓度反演结果发现,非同时观测气象参数的利用引起的浓度偏差最小在0.11 μg·mL-1,最大可达4 μg·mL-1;本论文的分析结果对基于光谱反演CO₂柱浓度算法的改进有着一定的参考价值。     

Large triplet pairing mixing in the FFLO state of spin fluctuation mediated superconductivity in Q1D systems

We study the Fulde–Ferrell–Larkin–Ovchinnikov (FFLO) state of spin fluctuation mediated superconductivity and focus on the effect of coexisting charge fluctuations. We find that (i) consecutive transitions from singlet pairing to FFLO and further to S_z=1 triplet pairing can generally take place upon increasing the magnetic field when strong charge fluctuations coexist with spin fluctuations and (ii) the enhancement of the charge fluctuations lead to a significant increase of the parity mixing in the FFLO state, where the triplet/singlet component ratio in the gap function can be close to unity. We propose that such consecutive pairing state transition and strong parity mixing in the FFLO state may take place in a quasi-one-dimensional organic superconductor (TMTSF)₂X.     

Simultaneous determination of homocysteine,methionine and cysteine in maternal plasma after delivery by HPLC‐fluorescence detection with DBD‐F as a label

An HPLC‐fluorescence (FL) method for determination of sulfur‐containing amino acids such as homocysteine (Hcy), methionine (Met) and cysteine (Cys) in human plasma was developed. The sulfur‐containing amino acids were labeled with 4‐(N,N‐dimethylaminosulfonyl)‐7‐fluoro‐2,1,3‐benzoxadiazole (DBD‐F). Calibration curves in the range of 1–100 µm (Hcy and Met) and 5–500 µm (Cys) indicated good linearities (r ≥ 0.998). The limits of detection at a signal‐to‐noise ratio of 3 were 0.13 (Hcy), 0.02 (Met) and 0.11 µm (Cys), respectively. Acceptable results for accuracy and precision of intra‐ and inter‐day measurements were obtained. The results of Hcy and Cys obtained by the proposed method indicated good correlations with the conventional method (r > 0.911, n = 20). Furthermore, the method was applied to determination of the sulfur‐containing amino acids in maternal plasma (n = 200) after delivery. The concentrations of Hcy, Met and Cys as a median (inter quartile range, Q₁ and Q₃) were 5.37 (3.32–7.79) μm , 25.20 (20.10–31.06) μm and 147.25 (102.81–189.31) μm , respectively. Copyright © 2012 John Wiley & Sons, Ltd.