Synthesis,characterization, and dyeing performance of some azo thienopyridine and thienopyrimidine dyes based on wool and nylon

A string of novel heterocyclic mono azo dyes were synthesized and their utilization in dyeing different fabrics as wool and nylon were discussed. Thienopyridine azo dyes 4 and 6 were prepared by reaction of chloro acetamidederivative 2 with diamino compounds to yield 3 and 5 , followed by reaction with NaNO₂/HCl and coupling with nucleophilic reagent. One-pot reaction of chloro acetamide 2 with ammonium thiocyanat in solvent ethanol gave the unexpected thienopyrimidine derivative 7 , which contain two active sites, the former is primary amine that was able to form diazonium salt that coupled with N,N-dimethylaniline, resorcinol, and/or self-coupling to afford the azo dyes 8-10 , and the latter is active methylene group that underwent coupling with different diazonium salts to give the azo thienopyrimidine derivative dye 11-15 . The dyeing performance of these azo dyes had been investigated in terms of their dyeing behavior and fastness properties on different fabrics. Results showed that the color strength (K/S) values, as well as, washing, rubbing, and resistance to acid, alkali and light showed high efficiency of these heterocyclic mono azo dyes to dye wool rather than nylon fibers.     

Synthesis and application of disazo reactive dyes derived from sulfatoethylsulfone pyrazolo[1,5-a]pyrimidine derivatives

Two models of heterocyclic reactive dyes based on disazo pyrazoloprymidine derivatives and possessing a sulfatoethylsulfone reactive group were synthesized and characterized by elemental analysis, IR and ¹H NMR spectroscopy. The dyes were applied to cotton, wool and silk fabrics. Effects of varying dyeing conditions were investigated. The results assessed for the exhaust dyeing methods on the different fabrics indicate that these reactive dyes showed high exhaustion and fixation values. The dyed fabrics also showed very good light fastness and good to excellent washing, rubbing and perspiration fastness.     

A study on multifunctional protein fibre with UV protection,moth repellency and antibacterial properties using ESIPT core containing benzimidazole and benzothiazole based functional acid azo dyes

Water soluble fluorescent acid azo dyes with benzimidazole and benzothiazole component having excited state intramolecular proton transfer (ESIPT) core were synthesised by diazo coupling. The structure of the dyes were analysed and confirmed by Fourier Transform Infrared – spectroscopy (FT-IR), elemental analysis, ¹H NMR and ¹³C NMR analysis. Absorption and emission characteristics of the dyes were studied in different polarity solvents shown bathochromic (red) shift as solvent polarity increases. Wool and silk fabric dyed with synthesised dyes displayed high exhaustion, uniform dyeing and good wet fastness properties. The dyed substrate showed green and purple fluorescence under UV light (366 ​nm) along with UV protection. Dyed wool fabric was also assessed for antibacterial activity by calculation of bacterial reduction Staphylococcus Auerus (Gram positive), Klebsiella Pneumonia (Gram negative) bacteria. The dyed wool were also examined for the resistivity against insect pests Anthrenus Flavipies (Le Conte) by calculation of the fabric weight loss, Mortality of moth and visible assessment of fabric attacked by moth after 14 days in given conditions. Consequently, it was demonstrated that wool fabric dyed with Benzimidazole and benzothiazole based acid dyes had various functionalities, such as UV protection, antibacterial activity and mild moth repellency.     

Synthesis and evaluation of a series of symmetrical hot brand bis azo reactive dyes using 4,4′-methylene-bis-metanilic acid on various fibre

4,4′-Methylene-bis-metanilic acid (A) was synthesized by the reaction between metanilic acid and formaldehyde. The compound (A) was used as a bifunctional middle component in the preparation of several symmetrical hot brand bis azo reactive dyes. The compound (A) was tetrazotized and coupled with various m-nitro anilino cyanurated coupling component to give various hot brand bis azo reactive dyes. The entired compounds have been identified by IR, ¹H NMR spectra and elemental analysis. The dyes were applied on silk, wool and cotton fabrics and their fastness properties were evaluated. All the dyes give good fastness properties. The percentage dye bath exhaustion was also been studied.     

Synthesis and characterization of reactive dyes based on 2-phenyl-3-[4′-(4″-aminophenylsulphonamido)]phenyl-4(3H)-quinazolinone-6-sulphonic acid

A series of new quinazolinone based mono azo reactive dyes (D_1–10) have been prepared by subsequent diazotization of 2-phenyl-3-[4′-(4″-aminophenylsulphonamido)]phenyl-4(3H)-quinazolinone-6-sulphonic acid (C) and coupling with various 4-chloro anilino cyanurated coupling components. These dyes give purple, red, orange and yellow color shades. All the reactive dyes were characterized by their percentage yield, UV–Vis spectroscopy, elemental analysis, IR spectroscopy, ¹H NMR spectroscopy and dyeing performance on silk, wool and cotton fibres. The percentage dye bath exhaustion on different fibres has been found to be reasonably good and acceptable. The dyed fibres show moderate to very good light fastness and good to excellent washing and rubbing fastness.     

Characterization,DFT calculations and dyeing performance on polyester fabrics of some azo disperse dyes containing pyrazole ring

A number of azo pyrazole derivatives and novel Schiff bases derived from azo diamino pyrazole were synthesized. These included 4-(2-arylhydrazono)-4H-pyrazole-3,5-diamines and N³,N⁵-dibenzylidene-4-(2-arylhydrazono)-4H-pyrazole-3,5-diamines. The chemical structures of the novel azo dyes were determined using UV–visible, IR, ¹H NMR, and ¹³C NMR spectroscopy. Dyeing process and tautomerism of the aforementioned azo compounds were predicted using DFT calculations. The electronic absorption spectra in methanol were observed and compared to those computed using B3LYP/6-31G(d,p). The dyeing performance of the produced disperse dyes was examined on polyester. The degree of exhaustion and the fastness properties of the dyed samples in terms of washing, perspiration, scorch, and light fastness were assessed. Moreover, the reflectance and color strength of the synthesized dyes were measured and discussed.     

Anthraquinone and Azo Dyes in Dyeing Processes of PET Films and PET Knitted Fabrics Using Supercritical CO2 Medium

Summary: Dyeing processes using supercritical fluid present advantages over the conventional dyeing process using aqueous medium. Previous works from our group on polymeric fibers such as N,N-dimethylacrylamide (DMAAm) modified poly(ethylene terephthalate), PET, showed higher sorption of disperse dyes in supercritical medium. Furthermore, recent studies showed that the association of UV radiation and DMAAm treatment leads to a better incorporation of dyes in modified PET soaked in aqueous medium. In this work, modified and non-modified PET knitted fabrics (KF) were dyed in supercritical CO₂ medium. Azo and anthraquinone dyes were used in order to compare the extent of incorporated dye in PET films and PET KF in supercritical CO₂. The dyeing process variables were studied by factorial design and by a response surface methodology (RSM) technique. The anthraquinone dye presented a better incorporation in PET than the azo dye. The UV light exposure and the dyeing times inputs showed positive main effects in the incorporation of dyes in PET films and PET KF. From the RSM data, DMAAm and UV light modified PET KF presented 7.43 mg of incorporated azo dye by g of PET if the optimized dyeing conditions, time: 135 min and pressure: 212 bar would be used. In the respective optimized dyeing conditions for the anthraquinone dye, time 150 min and pressure 229 bar, the incorporated dye would be 22.9 mg of dye by g of PET.     

The use of water-soluble phthalocyanines as textile dyes in nylon/elastane fabric: fastness and antibacterial effectiveness

This work reports on dyeing of nylon/elastane fabric with water-soluble phthalocyanines ( 1-4 ) bearing quinoline 5-sulfonic acid substituents on the peripheral or nonperipheral positions and determining the antibacterial efficiency of the phthalocyanine compounds and the dyed nylon/elastane fabrics. The light, washing, water, perspiration, and rubbing fastness properties of nylon/elastane fabrics dyed with phthalocyanines were also determined. The results showed that all dyed fabrics showed very good wet fastness values. The lightfastness value of the nylon/elastane fabric dyed with phthalocyanine dye ( 1 ) showed a much better value than the others. Also, the antibacterial efficiencies of the dyed nylon fabrics and the dye compounds were investigated against a gram-negative ( Escherichia coli ) and a grampositive ( Staphylococcus aureus ) bacteria by using disc diffusion method. The results showed that the dyed nylon/elastane fabrics and the compounds exhibited antibacterial activities against both bacteria.     

Colorimetric studies of heterocyclic monoazo reactive dyes and their dyeing applications on cotton,silk, and wool fibers

Heterocyclic quinazolinone-based hot brand monoazo reactive dyes were obtained by diazotization of 3-(4-aminophenyl)-2-phenylquinazolin-4(3H)-one and coupling with a variety of cyanurated coupling components. All the heterocyclic hot brand monoazo reactive dyes were characterized by elemental analysis (C, H, N) and by use of spectroscopic techniques (FT-IR, UV–visible, ¹H NMR). Their performance as reactive dyes was assessed on silk, wool, and cotton fabrics. The dyes were found to give a variety of color shades with very good depth and uniformity on the fibers. The fastness of all the dyes on the fibers was moderate to excellent. Colorimetric data (L*, a*, b*, C*, H*, and K/S) of the synthesized dyes were also studied in detail.     

液液萃取-分散液液微萃取-气相色谱-质谱联用测定纺织废水中痕量禁用偶氮染料

建立了液液萃取-分散液液微萃取-气相色谱-质谱联用技术测定纺织废水中痕量偶氮染料的方法。废水中的偶氮染料在碱性条件下经连二亚硫酸钠还原成芳香胺后,先用叔丁基甲醚液液萃取、盐酸反萃进行预浓缩及净化;再以乙腈-氯苯体系进行分散液液微萃取,气相色谱-质谱测定。对前处理条件进行了优化,考察了酸碱度及盐效应对芳香胺萃取效率的影响,结果表明：液液萃取过程中加入30 g NaCl,分散液液微萃取过程中加入1 mL 5 mol/L的NaOH调节体系至碱性才能达到较好的萃取效率。在优化的实验条件下,21种目标物均呈现良好的线性关系,其中13种芳香胺的线性范围为0.05~10 μg/L,7种芳香胺的线性范围为0.05~5 μg/L,2,4-二氨基苯甲醚的线性范围为20~100 μg/L,相关系数为0.996~0.999。20种芳香胺的检出限可达0.05 μg/L,2,4-二氨基苯甲醚检出限为20 μg/L。印染、机织、印花等实际废水加标试验表明,方法的回收率为75.6%~115.1%。该方法富集倍数高,检出限低,适用于纺织废水中痕量禁用偶氮染料的检测。     

Application of newly synthesized bisazo dichloro-s-triazinyl reactive dyes bearing 1,3,4-oxadiazole molecule

Novel bisazo dichloro-s-triazinyl (DCT) reactive dyes (5a–h) containing 1,3,4-oxadiazole molecule as a tetrazo component were synthesized and applied on silk, wool and cotton fibers by exhaust dyeing method. The structures of these dyes were confirmed by UV–vis, FT-IR, ¹H and ¹³C NMR and elemental analyses. The exhaustion, fixation and fastness properties of the dyed fabric were assessed and the results demonstrated that these dyes showed moderate to very good light and good to excellent washing and rubbing fastness properties. The colorimetric data (L¹, a¹, b¹, C¹, H¹, K/S) of these dyes have also been studied in detail.     

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.     

The interaction of anionic azo dyes with hen egg-white lysozyme: 1

The interactions between seven anionic azo dyes and hen egg-white lysozyme were investigated by means of visible absorption spectroscopic and lytic activity measurements. The dyes, for which no report on the interaction has appeared so far, were bound with lysozyme to different extents as a result of the differences in their chemical structures. Although most of the dyes formed 11 complex with lysozyme, two of them behaved differently. From the measurements of the absorption, lytic inhibition toward cell walls and competitive binding with substrate analogues, it was concluded that a major binding site of these dyes on lysozyme is a charged lysine residue in the vicinity of the subsitesD, E andF, and, in the case of a dye that forms 21 complex with lysozyme, and additional binding site is in the vicinity of the subsite B.     

The interaction of anionic azo dyes with hen egg-white lysozyme: 2

In continuation of our preceding study, this report describes pH and ionic strength dependences of the binding constants of six anionic azo dyes to lysozyme, the competitive binding of the dyes with the substrate analogues of lysozyme and the change in the circular dichroism of lysozyme by the dye binding. The binding constants were obtained from the difference spectra of visible absorption. With an increase in pH from 5.0 to 7.0 the constants for the dyes (1st of the two modes of the binding of a dye named D3) are reduced. The increase in ionic strength from 0.1 to 0.2 also reduces the values of the constant. Competitive binding was found between D3 and the analogues, but not for the other dyes. The change in the circular dichroism due to the electronic perturbation of tryptophyl residues in lysozyme was found. From these evidences, Lys 33 in lysozyme is pinpointed as the most credible binding site for the dyes (1st mode binding of D3). An unspecified location near the subsiteB in lysozyme is addressed for 2nd mode binding of D3.     

Delocalized cationic azo dyes containing a thiazole moiety

Several new delocalized cationic azo dyes incorporating a bathochromic thiazole moiety have been prepared in moderate to good yields. The synthesis involved the Knoevenagel condensation of an intermediate azo compound, bearing a terminal formyl group, with methylenic bases generated in situ from benzoazolium and quinolinium salts. All dyes display strong absorption around 700 nm and have shown negative solvatochromic behaviour.     

Synthesis of novel 1:2 Fe-complexed dye containing polyamine groups

A Fe-complexed dye containing crosslinkable polyamine groups was synthesized through diazotization and coupling reaction, chlorination,amination and metallization.The structure of the Fe-complexed crosslinking dye was characterized by FT-IR and Atomic Absorption Spectroscopic techniques.The dyeing and light fastness properties of the Fe-complex on silk and wool were tested,and the results showed that the novel Fe-complex exhibited both high fixation and good light fastness.     

Characterization of sulfonated azo dyes and aromatic amines by pyrolysis gas chromatography/mass spectrometry

Sixteen sulfonated and unsulfonated azo dyes as well as eleven sulfonated and unsulfonated aromatic amines were analyzed and qualitatively characterized by means of pyrolysis gas chromatography/mass spectrometry at different temperatures. Aniline and aminonaphthalene were found to be the dominant pyrolysis products of sulfonated aromatic amines and dyes. Azo dye and dye class specific key compounds such as benzidine, vinyl-p-base and 4-aminoazobenzene could be identified by pyrolysis gas chromatography/mass spectrometry of commercial acid, cationic, direct, reactive and solvent dyes. 500 degrees C was the optimal pyrolysis temperature for most of the pyrolyzed compounds. The method was applied to a dried sample of a textile wastewater concentrate from a dyeing process. Reactive azo dyes of the group of Remazol dyes and anthraquinone dyes could be identified as the major compounds of the sample. The finding of caprolactam (a printing additive) suggests that the wastewater contained effluent from a process of heat-activated printing with reactive dyes. p-Chloraniline, a banned aromatic amine, was identified. Chemical reduction of the wastewater sample prior to pyrolysis resulted in the release of volatile aromatic amines and aided the classification of several products of pyrolysis.     

Synthesis and dyeing properties of new disazo disperse dyes for polyester and nylon fabrics

Diazotized aryl amines were coupled with two stenhouse salt namely, N-(5-phenylamino-penta-4-ol-2,4-diene-1-ylidene)anilines hydrochloride [S₁ (RH) or S₂ (ROH)] to furnish two series of disazo disperse dyes (S₁D_1–10 and S₂D_1–10). The structure of all the dyes was established by estimating number of azo groups, elemental analysis and spectral studies (IR, ¹H-NMR, UV/Visible). The structure–property relationship was discussed by using electronic absorption spectra of the dyes. These dyes were applied to polyester and nylon fabrics as disperse dyes by using temperature exhaust dyeing method. The relevant dyeing characteristics, such as dyeability on fabrics, wash-fastness and light-fastness were evaluated. Fabrics dyed with these dyes furnished generally deep and bright intense hues ranging from light yellow to orange to reddish brown. The color fastness of the dyed fabric was assessed by determining wash-fastness and light-fastness properties.     

Dyeing of multiple types of fabrics with a single reactive azo disperse dye

Three novel reactive azo disperse dyes were prepared using 7-acetamide-4-hydroxy-2-naphthalene sodium sulphate as the precursor. The structure of the dyes has the combined characteristics of reactive, disperse, and cationic dyes. Under alkaline conditions (pH 9), the dyes can be applied to cotton, silk, wool, and nylon. Under neutral conditions, they can be used to dye polyester. Under acidic conditions (pH 4.5), they can colour acrylic fabric after conversion of the tertiary amine group to the quaternary ammonium cation. The colour-fastness of the dyed fabrics were also evaluated.     

Enhancement of azo dyes removal efficiency by using LDH/Tris/Pd catalyst: Kinetic studies

LDH/Tris/Pd (CaAl‐layered double hydroxide/tris (hydroxymethyl)aminomethane/palladium) was synthesized and appraised for its catalytic activity towards the degradation of two selected azo dyes. The decolorization of azo dyes, acid red 18 (AR 18) and reactive yellow 15 (RY 15), requires considerably small amounts of synthesized catalyst. Kinetic studies show that the catalytic decolorization of these azo dyes follows the first order kinetic model. The reported method is simple and applicable; in addition, the stable catalyst can efficiently decolorize model azo dyes with good recyclability. Therefore, LDH/Tris/Pd can be accepted as the possible component for the utilization in wastewater treatment.