Diffusion of nonionic azo dyes in nylon-6

Diffusion of 2,4-dinitroaniline and three nonionic azo dyes in Nylon-6 film was studied by analysis of the concentration-distance curves (profiles) of penetrants in the polymer. Actual diffusivities D_(c) of penetrants in polymer, diffusion coefficients as a function of the concentration C_f of penetrant in polymer, were calculated from the profile. It was found that D_(c) is almost constant or decreases gradually with decreasing C_f in the range of high-medium C_f but decreases appreciably with decreasing C_f at low C_f. The change in D_(c) with C_f was explained in terms of the dual-mode sorption-diffusion model. The penetrants diffuse in the polymer as two distinct species, i.e., a dissolved species and an adsorbed species. The former is the penetrant taken up by the polymer by a partition mechanism (dissolved species) and the latter is that taken up by Langmuir sorption (adsorbed species). The actual diffusivity D_P(c) of the dissolved species decreases with decreasing C_f. While the actual diffusivity D_L(c) of the adsorbed species normally increases gradually with decreasing C_f. D_P(c) is usually larger than D_L(c). © 1993 John Wiley & Sons, Inc.     

Photochromic properties of thienylpyrrole azo dyes in solution

The photochromic behaviour of thienylpyrrole azo dyes in THF solutions was studied for the first time. The photochromic properties are strongly dependent on the substitution pattern on the dyes. Nitro-substituted thienylpyrrole azo dyes are particularly interesting since they exhibit very fast colouration/decolouration processes. The activation energies of these compounds are among the lowest values reported for heterocyclic azo dyes. These compounds show aggregation phenomena in freshly prepared solutions of THF, which lead to variable photochromic behaviours. Only after 1-5 h the solutions reach equilibrium and then reproducible photochromic behaviour can be observed.     

Synthesis of iron-containing polymers with azo dyes in the backbones or side chains

The synthesis of cationic cyclopentadienyliron-containing polymers with pendent azobenzene chromophores was accomplished via metal-mediated nucleophilic aromatic substitution reactions. All of the desired polymers were isolated as vibrantly coloured materials and displayed excellent solubility in polar aprotic solvents. Cationic and neutral cyclopentadienyliron polymers incorporating azo dyes in the backbone were also prepared. Reactions of azo dyes with dichlorobenzene complexes allowed for the isolation of cationic cyclopentdienyliron (CpFe₊) complexes with azo dye chromophores. These complexes were then reacted with 1,1′-ferrocenedicarbonyl chloride to produce the trimetallic monomers with terminal chloro groups. These monomers contained two pendent CpFe₊ cations and a neutral iron moiety in the backbone. Nucleophilic substitution reactions of these monomers with oxygen and sulfur containing dinucleophiles gave rise to a new class of polymeric materials. The pendent CpFe₊ moieties could also be cleaved from the polymer backbones using photolysis to afford novel ferrocene based polymers. The UV-vis spectra of the organoiron monomers and polymers display similar wavelength maxima however incorporating azobenzene chromophores with electron-withdrawing substituent into the polymer chains resulted in bathochromic shifts of the λ_max values.     

皮革和纺织品中重叠峰偶氮染料的气相色谱-串联质谱检测技术

建立了气相色谱-串联质谱一次进样同时检测重叠峰偶氮染料的分析方法.皮革和纺织品中的偶氮染料用柠檬酸盐缓冲液提取,再用连二亚硫酸钠将其还原裂解为胺类物质,经液-液萃取、浓缩处理,所得残渣用甲醇溶解,通过VF-5ms色谱柱分离,采用串联质谱的多反应监测模式开设多通道存储子离子信息,进行定性、定量分析.实验结果表明:优化质谱分析条件后,气相色谱一串联质谱可进一步消除杂质干扰,分离共流出组分.大部分芳香胺3种浓度水平的加标回收率(n=6)保持在71%～94%之间,检测限为0.008～0.672μg/mL(S/N=3),相对标准偏差(n=6)小于11%,2～50μg/mL浓度范围内线性相关系数大于0.9917,满足禁用偶氮染料的分析要求.     

Disulfonated azo dyes: metal coordination and ion‐pair separation in twelve MII compounds of Ponceau Xylidine and Crystal Scarlet

The structures of seven divalent metal cation compounds of Ponceau Xylidine {PX; systematic name of dication: 4‐[2‐(3,4‐dimethylphenyl)hydrazin‐1‐ylidene]‐3‐oxo‐3,4‐dihydronaphthalene‐2,7‐disulfonate}, also known as Acid Red 26, CI 16150, and of five divalent metal cation compounds of Crystal Scarlet {CS; systematic name of dication: 8‐[2‐(naphthalen‐1‐yl)hydrazin‐1‐ylidene]‐7‐oxo‐7,8‐dihydronaphthalene‐1,3‐disulfonate}, also known as Acid Red 44, CI 16250, are presented. These are hexaaquamagnesium(II) PX dimethylformamide (DMF) monosolvate, [Mg(H₂O)₆](C₁₈H₁₄N₂O₇S₂)·C₃H₇NO, (I); heptaaquacalcium(II) PX 2.5‐hydrate, [Ca(H₂O)₇](C₁₈H₁₄N₂O₇S₂)·2.5H₂O, (II); catena‐poly[aqua(μ‐DMF)tris(DMF)bis(μ₃‐PX)distrontium(II)], [Sr(C₁₈H₁₄N₂O₇S₂)(C₃H₇NO)₂(H₂O)_0.5]_n, (III); the transition‐metal series hexaaquametal(II) PX DMF monosolvate, [M(H₂O)₆](C₁₈H₁₄N₂O₇S₂)·C₃H₇NO, where M (metal) = Co, (IV), Ni, (V), Cu, (VI), and Zn, (VII); heptaaquacalcium(II) CS monohydrate, [Ca(H₂O)₇](C₂₀H₁₃N₂O₇S₂)·H₂O, (VIII); octaaquastrontium(II) CS monohydrate, [Sr(H₂O)₈](C₂₀H₁₃N₂O₇S₂)·H₂O, (IX); catena‐poly[[triaqua(DMF)barium(II)]‐μ‐CS], [Ba(C₂₀H₁₃N₂O₇S₂)(C₃H₇NO)(H₂O)₃]_n, (X); tetrakis(DMF)(CS)copper(II) monohydrate, [Cu(C₂₀H₁₃N₂O₇S₂)(C₃H₇NO)₄]·H₂O, (XI); and catena‐poly[[[aquatris(DMF)zinc(III)]‐μ‐CS] diethyl ether hemisolvate], {[Zn(C₂₀H₁₃N₂O₇S₂)(C₃H₇NO)₃(H₂O)]·0.5C₄H₁₀O}_n, (XII). In all cases, the structures obtained were solvates with dimethylformamide (DMF) and/or water present. The disulfonated naphthalene‐based azo anions adopt hydrazone tautomeric forms. The structures of the Mg salt and of four transition‐metal forms (M = Co, Ni, Cu and Zn) of PX are found to form an isostructural series. All have solvent‐separated ion‐pair (SSIP) type structures and the formula [M(H₂O)₆][PX]·DMF. The Ca salt of PX also has an SSIP structure, but has a higher hydration state, [Ca(H₂O)₇][PX]·2.5H₂O. In contrast, the Sr salt of PX, [Sr(PX)(DMF)₂(H₂O)_0.5]_n forms a one‐dimensional coordination polymer. Both the Ca and the Sr salt of CS have an SSIP structure, namely [Ca(H₂O)₇][CS]·H₂O and [Sr(H₂O)₈][CS]·H₂O, whilst the heavier Ba analogue, [Ba(CS)(DMF)(H₂O)₃]_n, forms a one‐dimensional coordination polymer. Unlike PX, two CS structures containing transition metals are found to be coordination complexes, [Cu(CS)(DMF)₄]·H₂O and {[Zn(CS)(DMF)₃(H₂O)]·0.5Et₂O}_n. This suggests that CS is a better ligand than PX for transition metals. The Cu complex forms discrete molecules with Cu in a square‐pyramidal environment, whilst the Zn species is a one‐dimensional coordination polymer based on octahedral Zn centres.     

Multilayered particle‐packed column: Evaluation and comparison with monolithic and core–shell particle columns for the determination of red azo dyes in Sequential Injection Chromatography

A recently presented new type of “multilayered” organic–inorganic hybrid silica particle packed column YMC‐Triart C₁₈ (50 mm × 4.6 mm, 5 μm) was used for the development of a sequential injection chromatography method for determination of five azo dyes (Sudan I, Sudan II, Sudan III, Sudan orange G, and para red) in selected food seasonings. The use of a novel sorbent brings attractive features, reduced backpressure, and broader chemical stability together with high separation performance, which are discussed and compared with that of three types of columns typically used in medium‐pressure flow chromatography techniques (classic monolithic, narrow monolithic, and core–shell particle columns). The separation was performed in gradient elution mode created by the zone mixing of two mobile phases (acetonitrile/water 90:10, 1.5 mL + acetonitrile/water 100:0, 2.3 mL) at a flow rate of 0.60 mL/min and time of analysis <9.5 min. The spectrophotometric detection wavelengths were set to 400, 480, and 500 nm. The high performance of the developed method with multilayered particle column was well documented and the results indicate a broad capability of sequential injection chromatography.     

多孔芳香骨架吸附剂-固相萃取-高效液相色谱法同时测定辣椒粉中4种偶氮类染料

建立了固相萃取-高效液相色谱同时测定辣椒粉中对位红、酸性橙Ⅱ、苏丹红Ⅰ和苏丹红Ⅱ 4种偶氮染料的方法。以多孔芳香骨架-6（PAF-6）材料作为固相萃取吸附剂，考察并获得了影响自制固相萃取柱的萃取效率和吸附容量等主要因素。在优化条件下，4种目标分析物的检出限（LOD）为1.5~7.0 μg/L（信噪比S/N=3），定量限（LOQ）为5.0~22.1 μg/L（S/N=10），加标回收率为76.5%~89.8%，相对标准偏差（RSD）均不大于5.3%（n=6）。此外，基于量子化学计算，考察了PAF-6与目标分析物之间的相互作用机制，结果表明，目标分析物可以稳定地吸附在PAF-6分子上。该方法准确可靠，具有良好的回收率和较高的灵敏度，可用于辣椒粉中4种偶氮类染料的检测。