Substitutes for 1-naphthylamine. Part 3-disazo direct dyes with 3-amino-4-methoxyacetanilide and 1-naphthylamine components

A parallel series of dyes using 3-amino-4-methoxy acetanilide and 1-naphthylamine as intermediate components, and 6-(N-phenyl)-amino-1-naphthol-3-sulphonic acid as a coupling component, together with some well known disazo components, have been synthesised and compared in order to identify effective substitutes for 1-naphthylamine.     

Azo-hydrazone tautomerism in azo dyes. I. A comparative study of 1-phenylazo-2-naphthol and 1-phenylazo-2-naphthylamine derivatives by electronic spectroscopy

Derivatives of 1-phenylazo-2-naphthol have been the subject of research for nearly a century, and their tautomeric behaviour is now well understood. This contrasts with sparse and controversial reports on the structure of naphthylamine analogues. To remedy this situation, a comparative study, involving compounds from both phenylazo-naphthol and naphthylamine series with OMe, CN and NO₂ substituents in the 4′ position has been started. HMO calculations indicated that the azo form of 1-phenylazo-2-naphthylamine is significantly more stable than the hydrazone, whereas the π bonding energies of the corresponding naphthol tautomers are of comparable magnitude. The validity of the Hückel calculations was checked on a greater set of phenylazo dyes with different coupling components. Results from electronic absorption spectroscopy show a frozen equilibrium with naphthylamine derivatives. From a McRae type analysis of the solvent-induced frequency shifts in various media an argument for the azo structure of all investigated 1-phenylazo-2-naphthylamines could be obtained. PPP calculations of spectral properties support this assignment.     

A study of some monoazo dyes containing the 1H-benzotriazole nucleus

Dyes containing the benzotriazole nucleus with various groups imparting a chelating property to the dye molecules have been synthesised. The dyes showed interesting properties for application to cotton and polyester.     

Azo-hydrazone tautomerism in azo dyes. IV. Colour and tautomeric structure of adsorbed 1-phenylazo-2-naphthylamine and 1-phenylazo-2-naphthol dyes

The tautomeric compositions of 1-phenylazo-2-naphthylamines (1), -naphthols (2) and their monosulphonates (3 and 4) have been investigated in the adsorbed state either on dyed polyester and wool fibres or in KBr pellets by means of scattered transmission, diffuse reflectance and Raman spectroscopy. The azo structure predominates in the naphthylamine series (1 and 3) in accord with previous results in solutions or with predictions by the perturbational molecular orbital theory. The major tautomer of the investigated naphthols (2 and 4) is mainly h, but both forms are present in 2(p-MeO) and 4(p-MeO) in comparable concentrations. Their h content depends on the nature of the substrate and increases in the order PES < WO < KBr. The colour is influenced by crystal field effects in the solid state as was shown for 1(p-NO₂). Utilizing a set of inductively active substituents for R, the frequency of the first absorption band of the dyes correlates well with Hammett σ, yielding a positive slope with the hydrazones and a negative one with the azo tautomers. This behaviour leads to an inversion of the colour sequence upon changing the tautomer composition both in solution and in the adsorbed state and can be generalized by perturbational MO arguments.     

The influence of methyl groups on the colour and dyeing properties of acid dyes derived from 1-amino-4-bromo-anthraquinone-2-sulphonic acid and arylamines

Four blue acid dyes were synthesized by condensation of bromamine acid with aniline, 2,4-dimethylaniline, 2,6-dimethylaniline and 2,4,6-trimethylaniline. It was found that the number and orientation of the methyl groups on the 4-phenylamino substituent affected both the colour and dyeing properties of the dyes. The more methyl groups present, the higher was the dye uptake and the better the fastness to wet treatments. When a methyl group is present in the ortho position of the phenylamino group, the hue of the dyes is hypsochromically shifted.     

2-羟基-4-甲氧基二苯甲酮-5-磺酸的极谱行为研究

用线性扫描极谱法研究了2-羟基-4-甲氧基二苯甲酮-5-磺酸(又名BP-4)的极谱行为。在2.0 mol/L H2SO4溶液中,BP-4产生还原波,波形好,其二阶导数峰电位为-0.93 V(vs.SCE),峰电流与其浓度在1.0×10-7～1.0×10-5mol/L的范围内呈良好的线性关系,线性方程为ip″(nA/s2)=187.5 1.558×108c,相关系数r=0.9996。初步讨论了电极过程及电极反应机理,该波为不可逆波。     

Solubilisation of dyes by surfactant micelles. Part 1; Molecular interactions of azo dyes with nonionic and anionic surfactants

An ultraviolet-visible spectroscopic investigation has been made of the interactions of a specially synthesised series of substituted, model arylazonaphthol dyes with nonionic and anionic surfactants. Changes in spectral features were recorded above the critical micelle concentrations, suggesting specific interactions of dyes with micelles of the respective surfactants. The affinity of the dye for the surfactant micelles increased when various p -substituent were incorporated in to the dyes. Similarly, there was a shift in azo–hydrazone tautomeric equilibria and an increase in measured dye p K _a values. Models are proposed for the location of dyes in nonionic or anionic micelles. Unlike earlier studies, it is concluded that the solubilised dye experiences only one environment in nonionic micelles but the specific location, i.e. whether preferentially incorporated in the hydrophobic micellar interior or in the more hydrophilic, outer polyoxyethylene layer, depends upon the nature of the substituent.     

An efficient nano-adsorbent via surfactants/dual surfactants assisted ultrasonic co-precipitation method for sono-removal of monoazo and diazo anionic dyes

To preserve the environment for civilization, we should remove the pollutants like toxic dyes by friendly and cost efficacious method. In this study, the effect of surfactants or mixed surfactants on physicochemical, optical and adsorption properties of ternary mixed oxide CeO₂-ZrO₂-Al₂O₃ (CZA) are investigated. The ternary mixed oxide CZA was prepared by surfactants or mixed surfactants assisted ultrasonic co-precipitation method. The physicochemical and optical properties are estimated by different techniques like XRD, TEM, EDX, FTIR, S_BET and UV–Vis/DR. The CZA_T and CZA_C have hybrid shapes and high surface area. The adsorption properties of ternary mixed oxides adsorbents were characterized by sono-removing anionic dyes such as Congo red (CR) and Remazol red RB-133 (RR). The different factors like contact time, different dye concentrations and temperatures also studied. The kinetics and isotherms applications showed that, the adsorption process was followed pseudo second order kinetics and the Freundlich isotherm model. Also, the adsorption is spontaneous and endothermic process through the thermodynamic study. Finally, the results showed that the ternary mixed oxide nano-adsorbent (CeO₂-ZrO₂-Al₂O₃₎ is promising and functional materials for anionic dye sweep from wastewater.     

Solubilisation kinetics of some monoazo naphthalimide disperse dyes containing butyric acid and investigation of fastness properties of the dyes on polyester

In this paper, the solubilisation kinetics of three novel monoazo disperse dyes based on naphthalimdes incorporating a butyric acid group were investigated in different conditions using spectrophotometry. All dyes showed a reasonable level of solubilisation in alkaline media. Kinetic studies of the solubilisation reaction of the dyes in alkaline media showed that the rate of solubilisation of all dyes is a pseudo first‐order reaction equation. The rate constants of the solubilisation reaction of the dyes in alkaline media indicated that dye 3 , which is prepared by the diazotisation of 4‐amino‐n‐butyric acid 1,8‐naphthalimide and coupled with N,N‐diethy‐n‐hydroxyethyllaniline, has the highest rate of reaction and dye 1 , which is prepared by the diazotisation of 4‐amino‐n‐butyric acid 1,8‐naphthalimide and coupled with N,N‐diethylaniline, has the lowest rate. The dyes were applied on polyester fabrics and their fastness properties were examined. The dyed fabrics showed a good to excellent degree of wash and rubbing fastnesses after replacing reduction clearing with alkali clearing.     

Differential dyeing cotton. Part 2-stoichiometry of interaction with acid and direct dyes

The stoichiometry of interaction of both acid and direct dyes with cotton modified with a reactive cationic reagent has been examined. In the case of the acid dyes adsorption is principally by a specific site mechanism and gives a 1:1 ratio between cationic sites on the cotton and sulphonate groups on the dyes, although some diffuse adsorption occurs with the more hydrophobic dyes. The direct dyes show a much greater amount of diffuse adsorption in addition to specific site adsorption. The results show that the presence of the cationic sites enhance the amount of dye taken up by diffuse adsorption and a mechanism for this is proposed.     

Synthesis and properties of 5-substituted 2-thiobarbituric acid dyes

The systematic synthesis of 5-substituted 2-thiobarbituric acid dyes (5-p-methoxy- and 5-p-dimethylamino-benzylidene-, cinnamylidene-, and phenylpentadienylidene-1, 3-disubstituted 2-thiobarbituric acids) is described and their absorption characteristics are reported.     

Azo—hydrazone tautomerism in azo dyes. II. Raman,NMR and mass spectrometric investigations of 1-phenylazo-2-naphthylamine and 1-phenylazo-2-naphthol derivatives

In a comparative study 1-phenylazo-2-naphtylamines, 1(R), and 1-phenylazo-2-naphthols, 2(R), with R = MeO, CN and NO₂ have been investigated by means Raman, NMR and mass spectroscopy in order to elucidate their tautomeric structures. Based on Raman spectra obtained under resonance conditions, the trans azo structure has been inferred for 1(R) with all the substituents under scrutiny. From the naphthol derivatives the hydrazone predominance has been confirmed for 2(CN) and 2(NO₂) in agreement with previous reports using different techniques. No useful Raman spectrum could be obtained, however, for 2(MeO) due to the inherent fluorescence of this dye. Here nuclear magnetic resonance proved to be helpful, yielding a K_T of 0·7 from both ¹³C and ¹H chemical shift arguments. For the other five dyes the Raman results have been corroborated by the measurement of carbon and proton chemical shifts [δ(C-2), δ(H-3) and δ(H-8)] and the coupling coupling constants J(H-3, H-4). In the mass spectrometer all compounds behaved similarly irrespective of the tautomeric structures in solution or in the solid state with an 'azo-type' fragmentation pattern originating from a primary CN cleavage of the molecular ion. A theoretical discussion is provided to show that this decomposition pathway for the hydrazones is not contradictory to the results obtained above. An initial CN cleavage instead of the generally assumed NN cleavage of the hydrazone molecular ion can occur in certain cases, particularly with electron withdrawing R, thus leading to the observed azo type decomposition. From the present results it became obvious that mass spectrometry is not a generally applicable tool for azo-hydrazone structure discrimination.     

Anionic coloration of acrylic fibre. Part 1: Efficient pretreatment and dyeing with acid dyes

Anionic dyeable acrylic fibre has been obtained by a viable and efficient pretreatment process using hydroxylamine hydrochloride in the presence of acetate salt. The chemical modification relies on an amidoximation reaction that partially converts cyano groups present in the fibre to amidoxime groups. Different factors that may affect the pretreatment process have been investigated. The pretreated fabrics were dyed with CI Acid Red 1 and CI Acid Green 16 and gave improved dyeability over untreated fabrics due to the ion–ion interactions between the sulphonic groups present in the dye molecules and the protonated amino groups present in the fibres. The treated dyed fabrics also showed excellent fastness properties. Fibre characterisation (nitrogen content, tensile strength, shrinkage, infrared spectra and X-ray diffraction) proved the success of the amidoximation reaction.     

Novel azo dyes derived from phthalimide. Part 1: Synthesis and spectroscopic properties

A series of azo dyes has been synthesised based on N -alkylphthalimide diazo components featuring one of three different alkyl groups. An analogous set of dyes was prepared in which the N -alkylphthalimidylazo systems bore an o,o -dibromo-substitution pattern. In these cases, cyanodebromination was performed to give the corresponding dicyano analogues. All the synthesised intermediates and dyes were characterised by mass spectrometry, proton nuclear magnetic resonance spectroscopy and elemental analysis. The absorption maxima of the dyes in dimethylformamide (N,N-dimethyl ∼) were observed to be in the range 435–608 nm and found to be consistent with results seen in previous studies of conventional monoazo disperse dyes. Replacement of both halogens in the dibromo-substituted dyes with cyano groups led to large bathochromic shifts (128–141 nm) in absorption maxima. Bathochromism was also observed when acetylamino groups were present on the coupler ring ortho to the azo link. However, variation of the N -alkyl function on the imido ring from n -butyl to sec -butyl and iso -propyl had little effect on absorption maxima, values being similar to that reported for the parent N -unsubstituted analogue.     

Correlation between the bioelimination of anionic dyes by an activated sewage sludge with molecular structure. Part 1: Literature review

Published literature from the past 30 years concerning the removal of dyes from textile effluent has been reviewed. The relationship between the bioelimination by activated sewage sludge and the molecular structure of anionic, water-soluble dyes has been examined. Bioelimination of many commercially available dyes as a mechanism for decolorising textile waste waters has been shown to be an inefficient process. However, the information collated will be used as the basis for development of novel reactive dyes for potential commercial application.     

Azo—hydrazone tautomerism in azo dyes. III. The tautomeric structure of 1-(4′-nitrophenylazo)-2-naphthylamine from crystal structure determination

The structure of 1(NO₂)—dioxane 2:1 solvate single crystal has been determined by direct methods and refined by analysis of the three-dimensional Mo Kα intensity data. The unit cell is monoclinic, space group P2₁/c with a = 8·960(3), b = 6·386(2), c = 30·141(11) Å, β = 108·56(2)°. Least-squares refinement of all positional and thermal parameters (hydrogen atoms isotropic) with 1458 independent reflections out of 2817 gave a final R-index of 0·069. The dye molecule is almost planar and of trans configuration. The nitro group, however, is significantly twisted out of the molecular best plane. Six-membered chelate ring structures are formed by intramolecular NH···N bonds while intermolecular NH···O interactions give rise to complex formation involving two dye and one dioxane molecules in a centrosymmetrical arrangement. Two such complexes are accommodated in the unit cell.Based on the observed molecular geometry and quantum chemical (SCF—MO) calculation of bond dimensions a strong predominance of the azo tautomer was concluded for 1(NO₂). This assignment is further supported by empirical correlations, using CN and NN bond distances from a great variety of reported azo and hydrazone structures which are compiled here for the first time. The mobile hydrogen is attached to the amine nitrogen [R(NH) = 1·04(5) Å] thereby excluding a major participation of the hydrazone form. These findings compare well with those for solutions and are in accordance with previous quantum chemical predictions.     

Neutral-fixing reactive dyes for cotton. Part 1 —synthesis and application of quaternised S-triazinyl reactive dyes

A number of different tertiary amines have been employed to prepare the corresponding quaternised triazines from a selected monochloro-s-triazine reactive dye. Preparation conditions have been established along with suitable analytical methods. The reactivity of the quaternised dyes with cellulose has been determined, special attention being paid to neutral fixation at high temperatures (100°C). Good neutral fixation was achieved with all the tertiary amine derivatives studied. In the case of the nicotinamide derivative an anomalous hydrolysis reaction involving ring opening was noted; this reaction led to the formation of aminotriazine rather than the expected hydroxytriazine.     

Synthesis,spectral properties and dyeing on polyester of monoazo dyes from indol‐2‐one derivatives

Three series of phenylazo disperse dyes were prepared by coupling diazotised 4‐aniline dyes with 5‐indol‐2‐one dyes. The structures of these dyes were determined by proton nuclear magnetic resonance, Fourier Transform–infrared and elemental analysis. The effects of solvent on the ultraviolet–visible absorption spectra of these dyes were studied. The dyes displayed a λ_max shift of between 399 and 438 nm. The dyes were finally applied in the dyeing of polyester fibres in order to investigate their colour range and dyeing properties. Most of the dyes displayed high rubbing fastness and good washing and sublimation fastnesses on polyester fibres.     

8-羟基喹啉-5-磺酸共振光散射法测定铅

在pH 5.0 BR缓冲液及阳离子表面活性剂CTMAB存在下,8-羟基喹啉-5-磺酸与Pb2+相互作用形成配合物,导致体系的共振光散射(RLS)强度增强,且在8.01×10-8～1.2×10-5mol/L范围内,体系ΔI强度与Pb2+的浓度有良好的线性关系,其回归方程为:ΔF=–91.23+61.21c(×10-6mol/L),相关系数r=0.997 6,检出限为2.40×10-8mol/L,相对标准偏差(RSD)在2.15%～4.01%。用于环境中水样的测定,回收率在96.3%～99.6%。该方法简单、快速、灵敏度高。