Polyfluoroalkyl substituted anthraquinone dyes

A number of new amino- and hydroxy-anthraquinone dyes with 1,1-dihydropolyfluoroalkyl groups at the nitrogen and oxygen atoms have been prepared. The influence of polyfluoroalkyl groups on the colour of these anthraquinone dyes has been studied. The replacement of the hydrogen atom in the oxy group by polyfluoroalkyl radicals causes a stronger hypsochromic shift of the absorption maximum than the same replacement in the amino group.     

Synthesis of temporarily solubilised azo disperse dyes containing a β‐sulphatoethylsulphonyl group and dispersant‐free dyeing of polyethylene terephthalate fabric

Disperse dyes containing a β‐sulphatoethylsulphonyl group have temporary solubility and can be applied for dispersant‐free dyeing of hydrophobic fibre. Six novel temporarily solubilised azo disperse dyes having a β‐sulphatoethylsulphonyl group in their structures were synthesised, and their dyeing properties on polyester were investigated. As a dye intermediate, a diazo component having dibromo groups was prepared, and 4‐diethylamino‐4′‐(2‐sulphatoethylsulphonyl‐4,6‐dibromo)azobenzene dyes were prepared by a diazo‐coupling reaction. Then, the dyes containing dicyano groups were prepared by cyanation of corresponding dyes with dibromo groups. The absorption maxima of the dyes were affected by the substituents in the diazo and coupling component rings and varied from 434 to 616 nm in dimethylformamide. Polyethylene terephthalate woven fabric could be dyed with the synthesised temporarily solubilised dyes without using any dispersants. Dyebath pH affected the K/S value at maximum absorption as well as percentage exhaustion on polyethylene terephthalate fabric, and the optimum pH was 5. The dyes gave brownish orange, red, purple, and greenish blue hues on polyethylene terephthalate fabrics, and colour build‐up was good. Wash fastness was good to excellent, rubbing fastness was moderate to excellent, and light fastness was poor to moderate.     

Structure—wet fastness relationships of some blue disperse dyes for polyester

A range of monoazo blue disperse dyes has been synthesised by coupling benzenoid and heterocyclic diazo components to aniline derivatives containing ester functions. The colour properties and wet fastness of the dyes on polyester at 1/1 standard depth have been examined and rationalised in terms of dye structure. Styryl dyes have also been prepared in order to compare their wet fastness properties to those of the azo dyes.     

Synthesis and properties of novel aziridinyl azo dyes from 2-aminothiophenes—Part 2: Application of some disperse dyes to polyester fibres

A series of yellow to greenish-blue aziridinyl azo dyes and their azo precursors containing a thienyl coupling moiety has been applied to conventional polyester fibre as well as microdenier polyester by high temperature exhaust dyeing. Heat transferability of these dyes onto polyester fibre has also been examined, using conventional heat-transfer printing techniques. The relevant dyeing characteristics, heat transferability, build-up, dyeability on microfibre polyester, washfastness and lightfastness are given. These aziridinyl dyes are reactive to polyester fibres under HT dyeing conditions. Fabrics dyed with aziridinyl dyes are more resistant to solvent extraction than those dyed with conventional dyes. Residual liquors showed only a pale colour when fabric dyed with aziridinyl dyes was dissolved and then precipitated, whereas a coloured polyester precipitate was obtained.     

Dyeing and fastness properties of phthalimide‐based alkali‐clearable azo disperse dyes on poly(ethylene terephthalate)

The properties of a series of phthalimide‐containing azo disperse dyes and azo dyes with N‐methyl phthalimide moieties in their diazo component were investigated and compared when used to colour polyethylene terephthalate. The N‐substitution of the phthalimide gave a hypsochromic effect on the colour change and better colour yields on poly(ethylene terephthalate) fabrics, probably because of the electron‐donating property of the methyl group and the higher hydrophobicity of phthalimide‐containing azo dyes compared with those containing phthalimide moieties. The results show that phthalimide‐based azo disperse dyes have excellent dyeing fastness properties and that high wash fastness can be achieved using alkali clearance. This alternative clearance method is important for reducing the environmental impact of the dyeing process by replacing reductive clearing and, in particular, by removing the need for sodium hydrosulphite, which creates a high biological oxygen demand when released in conventional disperse dyeing effluent and which generates aromatic amines.     

分散染料在涤/锦双组分纤维上色差的色度学分析

将涤 /锦复合丝分离成单一组分的超细涤纶和锦纶。用常用的分散染料同浴染色后 ,测定了各染色样品的颜色三刺激值 ,并经过色度学计算。实验分析表明 ,分散染料对锦纶染色物的反射光主波长值较相应涤纶染色物向长波方向移动 ;蒽醌类分散染料在锦纶上的得色量较小 ,彩度较低 ;而偶氮类分散染料对涤 /锦染色的总色差较小 ,较适合于涤 /锦复合丝的染色。     

Properties of Monoazo Disperse Dyes,Derivatives of 3– and 4–Aminophthalimide

The synthesis of several disperse dyes, from 3–amino–12–phthalimide and its N–methyl derivative as diazo component and N, N–dialky lanilines as coupling component is described. The dyeing behaviour and some physical properties of these dyes are investigated and compared with those of isomeric dyes containing azo groups in the 4–position, previously studied [5]. These properties were found to be considerably affected by the presence of an alkyl sub–stituent on the nitrogen atom of imide group. Further, dyes containing unsubstituted –NH groups showed somewhat better thermal properties (higher melting points and dyeings of better fastness to sublimation), but at the same time their dyeability was worse for all the known processes of dyeing polyester fibres. Based on the i. r. and visible spectra of the dyes under investigation, it was concluded that the dyes containing unsubstituted –NH groups are highly associated; dyes containing azo groups in the 4–position associate to give one product, whereas association of the dyes with azo groups in the 3–position leads to two different products.     

Novel photochromic 2,2′-bithiophene azo dyes

The photochromic properties and colour constancy of two series of 2,2′-bithiophene azo dyes in THF solution were strongly dependent on the substitution pattern of the dyes. Under visible irradiation (>420 nm) while some dyes exhibited a significant change in colour intensity others exhibited an almost stable absorption. The photokinetic parameters of the systems are also described.     

Synthesis of yellow pyridonylazo colorants and their application in dye–pigment hybrid colour filters for liquid crystal display

Nine yellow azo dyes were designed and synthesised by using different diazo components and pyridonyl coupling components for application in dye–pigment hybrid colour filters for liquid crystal displays. The synthesised dyes were characterised by proton nuclear magnetic resonance and elemental analysis. The thermal stability was examined by thermogravimetric analysis, and solubility was estimated in industrial solvents such as N-methyl-2-pyrrolidone and propylene glycol methyl ether acetate. The dyes, which exhibited suitable physical properties for use in a dye–pigment hybrid colour filter, were fabricated into colour filters, and their optical properties were measured.     

N-(1,1-dihydro)polyfluoroalkyl substituted triphenylmethane dyes

A number of new triarylmethane and styryl dyes with 1,1-dihydropolyfluoroalkyl groups at the nitrogen atoms have been prepared. We have studied the influence of polyfluoroalkyl groups on the colour of these triarylmethane and styryl dyes. The accumulation of N-polyfluoroalkyl radicals in the molecule of triarylmethane dyes exerts a hypsochromic shift of absorption maxima. The styryl dyes absorb at shorter wavelengths than the styryl dyes with dimethylamino groups. These demonstrate the lessening of the basicity of the nitrogen atom, bonded with the 1,1-dihydropolyfluoroalkyl radicals. Nevertheless, RNCH₂(CF₂CF₂)_nH groups show themselves in the triphenylmethane and styryl dyes as sufficiently strong auxochromes.     

Photochromism of yellow azo dyes: a specific phenomenon of cotton dyed with reactive dyes

A method that is more sensitive than the ISO standard procedure for the detection and assessment of photochromism has been developed using a colour measuring device. Using this method the photochromism of various yellow azo reactive dyes applied to cotton has been studied. This has shown that azo dyes that can form a hydrazone tautomer tend not to be photochromic. In particular for pyrazole and hydroxynaphthalene azo dyes, the colour change is too small to be perceived by the human eye. Furthermore photochromism decreases with increasing size of the aromatic moieties attached to the azo group, as well as with the increasing number of substituents located ortho to the azo linkage. Finally the photochromism of dyeings with the golden yellow chromophore of structure IV was reduced when they were finished with certain Knittex brands.     

Synthesis of stilbene-based azo dyes and application for dichroic materials in poly(vinyl alcohol) polarizing films

Stilbene-based azo dyes were synthesized and poly(vinyl alcohol) polarizing films were prepared using these dyes. Spectral properties of synthesized dyes were affected by amino group and intramolecular hydrogen bond in the coupling component ring. Adsorption of dye molecules onto the film was mainly influenced by hydrogen bonding interaction. Sodium sulfate added in the dyeing solution reduced the repulsion between dye anions and the film resulting in high degree of polarization. The increase in draw ratio improved the optical properties of the polarizing films.     

Synthesis and spectroscopic properties of novel azo dyes derived from phthalimide

A set of azo dyes has been synthesised using N -substituted phthalimides as diazo components. 3,5-Dibromo- N -substituted-phthalimidylazo derivatives were cyanated by cyanodehalogenation to give dicyano analogues. All of the synthesised intermediates and dyes have been characterised by mass spectrometry, ¹H-NMR or elemental analyses. The gamut of colour of the prepared dyes spanned much of the visible spectrum: absorption maxima of the dyes in formamide were observed in the range 436 to 609 nm. Consistent with results seen in previous studies of non-phthalimido monoazo disperse dyes, replacement of dibromo groups with dicyano functions in the phthalimide-based set led to large bathochromic shifts in absorption maxima, as did the introduction of acetylamino groups onto the coupler ring ortho to the azo link. However, switching an N -propyl function on the imido ring for a benzyl or 3-cyanopropyl substituent had little effect on absorption maxima. Good correlations between the observed absorption maxima of certain dyes and those of model analogues predicted by Pariser–Parr–Pople molecular orbital calculations were observed when steric effects were absent.     

Monoazo dyes for polyamide derived from 2-(4-alkylamido-2-hydroxyphenyl)benz-X-azoles

A series of 51 azo dyes derived from 2-(4-alkylamido-2-hydroxy-phenyl)benz-X-azoles was prepared. The dyes were used as disperse dyes for polyamide fibres. Physical, chemical, spectroscopic and technical properties of the dyes are discussed. A ‘spectroscopic constant’ is introduced to account for the colour of dyes in solution and of dyed fabrics.     

偶氮型分散染料结构与应用性能关系的研究

以2—氨基—3,5—二硝基噻吩和3—硝基—4—氨基笨甲酸甲酯为重氮组分,与不同的偶合组分偶合,合成了12只分散染料。测试了合成的染料和参比商品染料的应用性能。结果表明,合成的12只分散染料均具有良好的湿处理牢度、耐摩擦牢度及耐升华牢度,且优于参比商品染料。重氮组份相同时,偶合组分上带有双酯结构的染料,其湿处理牢度好于带有双乙酰氧乙基的染料。     

Synthesis of azo dyes from 6-amino-2-methoxy-quinoxaline and their use as disperse dyes for polyester fibres

6-Amino-2-methoxyqumoxaline (5) was sy nthe sise d from quinoxal-2-one (1) and used as diazo component as well as coupling component in the synthesis of azo dyes which were applied on polyester fibres as disperse dyes. The spectral properties and evaluation of the dyes are discussed.     

Synthesis of branched azo dyes based on benzene sulphonamide intermediates and their spectral properties

Benzene sulphonamide intermediates and two series of branched azo dyes (one series with H‐Acid as the coupling component, and the other, with a pyrazolone derivative as the coupling component) derived from them were synthesised. The molecular structures, spectroscopic properties and dyeing properties of the dyes obtained have been investigated. The results indicated that these dyes showed one dominant hue, despite each separate branch of chromophore, and, in the first series, four chromophoric groups led to only a threefold increase in the extinction coefficient, while the same comparison in the second series produced a fully additive effect, i.e. a fourfold increase. Compared with the mono‐branch dye of each series, the dyeing properties of the H‐Acid series were improved, whereas the pyrazolone series that were run diversely for the two series were synthesised from different coupling components. In addition, the crystallographic structure of the tri‐branch intermediate showed a non‐coplanar structure, which indicated that the derived dye would perform as the sum of three similar chromophoric units.     

Correlation between Rm and Standard Affinity of Some Anionic Azo Dyes on Cellulose

Results on affinity measurements and paper chromatography of some anionic azo dyes, obtained by diazotization of 4-aminobenzophenone, 2(4′-amino-benzoyl)thiophene, 4′-aminobenzanilide, 2-thiophene-carboxanilide-4′-amino, trans-4-aminostilbene and trans-2(4′-aminostyryl)thiophene and coupling with naphthionic acid, Nevile-Winther's acid, R acid, Hacid and chromotropic acid, have been reported. A linear relationship between the R_m value of the dyes and their standard affinity of dyeing has been observed for dyes with the same coupling component.     

Synthesis and properties of novel aziridinyl azo dyes from 2-aminothiophenes—Part 1: Synthesis and spectral properties

A series of yellow to greenish-blue aziridinyl azo dyes and their azo precursors containing a thienyl coupling moiety has been prepared from 2-aminothiophenes. The 2-aminothiophenes were readily obtained by using the Gewald reaction. It was found that cyclisation of the precursor dyes to the corresponding aziridinoazo dyes brought about bathochromic shifts in absorption maxima. Further spectral comparisons with N-phenylazo dyes derived from other terminal cyclic groups, such as four-, five-, six-, seven- and eight-membered rings, showed that the N-thienylaziridinoazo dyes are relatively bathochromic. From the viewpoint of solvatochromism, a clear contrast existed between λ_max values in different solvents; thus, a positive solvatochromism was observed in aprotic solvents, whereas a hypsochromic shift was brought about in polar protic solvents. PPP–MO calculations provided reliable predictions of absorption maxima for the various aziridinyl azo dyes and their precursor dyes.     

Azo dyes based on naphtholic oligomers

A series of oligomeric azo dyes has been prepared by coupling various diazonium salts of benzothiazoles to 1-naphthol/formaldehyde (1-NF) and 2-naphthol/formaldehyde (2-NF) oligomers. They were characterised in terms of their softening point, yield, colour, solubility and UV-VIS spectra. Structure-property relationships are discussed. Dyeing on polyester, nylon-6,6, and wool resulted in orange to red coloration having excellent light and washing fastness properties.