78 Egypt.J.Chem. Vol. 61, No.5 pp.897- 937 (2018) A Review on Synthesis of Nitrogen-containing Heterocyclic Dyes for Textile Fibers - Part 1: Five and Six-membered Heterocycles Tawfik A. Khattab1* and Mohamed Rehan2 1Dyeing, Printing and Auxiliaries Department, Textile Industries Research Division- National Research Centre, 33 El-Buhouth Street, Dokki, Cairo 12622, Egypt. 2Department of Pretreatment and Finishing of Cellulosic Fibers, Textile Industries Research Division National Research Centre, 33 El-Buhouth Street, Dokki, Cairo 12622, Egypt. HE SIGNIFICANCE of heterocyclic dyestuffs has recently increased due to their deep Thues and brightness, high color strength and better colorfastness compared to benzene analogous dyes. In this review, we give details outlining the synthetic approaches of all recently synthesized nitrogen-containing five and six-membered ring heterocyclic dyestuffs and their dyeing efficiency on textile fibers. Keywords: Nitrogen heteroatom, Heterocyclic, Dyes, Synthesis, Dyeing, Fabric. Introduction to their structure or according to end-use application on a certain substrate [23]. For instance, the disperse The former synthetic dyestuff, Mauveine, dyestuffs are characterized by a variety of chemical was recognized by Perkin in 1850s [1]. Dyes structures such as monoazo 1 [24], anthraquinone 2 have become indispensable tools for a variety of [25] and disazo 3 [26] structures (Fig. 1) and they are applications [2]. For instance, they act as colorants applied on hydrophobic substrates such as polyester for plastics, paper, ceramics, coatings, constructions, fibers. textiles and other highly sophisticated technology purposes [1-8]. Dyes are also used in sensors, inks, Heterocyclic-based materials are pervasive in tinting, adhesives, beverages, cosmetics, foodstuff, various fields of life sciences [27-35]. Heterocyclic polymers, optical data storage, leather, and wax dyes have been utilized in many fields, such as inkjet biomedicine [9-22]. Dyes that are employed for printing, photovoltaics, photography, digital optical textiles dyeing often come with particular properties storage, photodynamic therapy, bioimaging [2, 6, that include color fastness to sublimation, light, 12, 36-38]. Azo dyestuffs are now used to generate wash, perspiration and rubbing. Dyes used in textile nearly the whole range of color shades. For instance, industry can currently be described as mature. the anthraquinone derivatives of azo dyes are usually Nonetheless, it stays a vibrant and challenging employed for red, blue, violet and turquoise shades, field which necessitates a continuous production while other azo derivatives are used mostly to of novel materials due to the fast changing global manufacture yellow shades [2]. A long-term target of customers’ requirements. Several types of dye used dyestuffs research has been to merge both brightness today were recognized in 1800s [1, 2]. However, and colorfastness properties of anthraquinone-based the oil crisis in 1970s led to a sharp increase in the dyestuffs with the color strength and low cost of cost of raw materials for dyestuffs. This generated azo-based dyestuffs. This target is currently being a force toward lower cost dyestuffs by enhancing recognized with heterocyclic-based azo dyestuffs, the efficiency of the procedures and by replacing which can be divided into two major classes dyestuffs of low tinctorial strength, such as depending on the different chemical structures of the anthraquinone-based dyes, by tinctorially stronger heterocyclic coupling moieties and the heterocyclic dyes, such as heterocyclic-based benzofuranone and diazo moieties. All heterocyclic coupling moieties azo dyes. These subject matters are still significant that offer commercially significant azo dyestuffs and continuing, as are the modern matters of enclose mainly nitrogen heteroatom, such as indoles merchandise safety, quality, and environmental 4, pyrazolones 5, and in particular pyridones 6; protection [2]. Therefore, a variety of dyes have (Fig. 2) which afford yellow to orange shades on been reported. Dyestuffs can be classified according various substrates [2, 39]. *Corresponding author e-mail: [email protected] DOI: 10.21608/ejchem.2018.4130.1362 ©2017 National Information and Documentation Center (NIDOC) 898 TAWFIK A. KHATTAB AND MOHAMED REHAN HO O NH2 O N N N R N O2N O CH3 O O NH2 C.I. Disperse Yellow 5 Turquoise R=alkyl 1 2 CH3 N N N N CN HO N O 3 CH3 Fig. 1. Chemical structures of the disperse dyestuffs. CH R 3 R' R' N HO N N HO N O 4 R 5 Ar 6 R Fig. 2. Chemical structures of the azo dyes contain mainly nitrogen heteroatom. azopyridones are usually exist in the hydrazone Many dyes of yellow shade were of form. Typical examples include azopyrazolone azopyrazolones, however those have currently been C.I. Acid Yellow 23 7 and azopyridone 8 [40, 41] mostly replaced by azopyridones. Azopyridone (Fig. 3). In this review, the five and six-nitrogen dyestuffs of yellow shades are characterized containing heterocyclic dyes will be divided by better brightness and color strength, and according to the number of atoms building the commonly possess better colorfastness properties heterocyclic ring and the number of nitrogen than azopyrazolones. Both of azopyrazolones and heteroatoms included in their molecular structure. HO3S Cl CH3 N N COOH N CN H N N H O N O N O 7 8 CH3 SO3H Fig. 3. Chemical structures of azopyrazolone (7) and azopyridone (8). Egypt.J.Chem. 61, No.5 (2018) 899 A REVIEW ON SYNTHESIS OF NITROGEN-CONTAINING HETEROCYCLIC ... Dye classes exhaustion of chromium on fibers, reducing water The sort of dyestuff used to dye technical pollution by chromium [44]. textiles depends on the fiber characteristics, the target color, color strength, ease of coloration and Basic dyes colorfastness properties demanded by end-users. Basic dyes are cationic colorants with Some dyestuff types will dye some different substantivity for acrylic, polyester, and nylon fibers, but practically one fiber will dominate. For fibers on which basic dyes can introduce brilliant instance, disperse dyestuffs are mostly employed colors. Basic dyes can be used to dye proteinic to dye polyester fibers, although they can also be and cellulose acetate fibers, but their light fastness used to dye nylon, acrylic, and cellulose acetate on hydrophilic fibers is poor. The ionic attraction fibers, but with limits upon the color strength and among the basic dyestuff and the sulfonic acid color fastness properties [2, 42]. active sites in acrylic fibers is strong, which affords excellent colorfastness to wash. The close- Acid dyes packed physicochemical character of acrylic fibers Acid dyestuffs are anionic in nature with and the dye-fiber strong bond can lead to weak substantivity to proteinic fibers, such as wool, migration and leveling, but introduce excellent silk, nylon or any further garments containing color fastness against light. Acrylic fibers differ basic functional groups. Acid dyestuffs are broadly in their dye-ability due to the different usually applied from an acidic or neutral dye-bath. quantities of different monomers employed with Acid dyes can be printed onto wool, silk, nylon, polyacrylonitrile that adjust the requested glass and other fibers employing traditional printing transition temperature of the fiber. Print fixation thickeners followed steam fixation, washing, and is carried out by steam followed by washing, and then drying. Acid dyes enclose acidic functional finally drying [45]. groups, generally sulfonates. Wool, silk and nylon fibers enclose amino functional groups which is Azoic dyes protonated in acidic dye-bath to present active Azoic dyes are generated within the fiber + - typically by adsorption of an aromatic hydroxyl- basic sites (- NH3). The acid dye anion (-SO3 ), is therefore substantive to the fiber and is adsorbed, bearing substance, such as naphthol as the azoic creating a salt-like bond with the fiber active coupling active agent followed by azo-coupling basic sites. Monosulfonated acid dyestuffs can process with a stabilized aromatic diazonium be adsorbed to a higher level than di-, tri-, or salt to introduce a colored insoluble dye with tetrasulfonated acid dyestuffs because the amount azo functional group. The application technique of active basic sites on the fibers is restricted by must be performed with care as the ending color the fiber structure. Therefore, the color strength is is only achieved after soaping off to eliminate usually higher with monosulfonated acid dyestuffs any remained traces of the azoic starting on wool which is characterized by higher active components located on the fiber surface that may basic sites than nylon and silk. However, the acid provide inferior colorfastness to washing and dye solubility in water increases upon increasing rubbing. Although azoic dyes are inexpensive the number of sulfonate groups [43]. to introduce red and black colors because their color range is currently more restricted as some Mordant dyes diazo compounds prepared from certain aromatic Chrome mordant dyestuffs are the only amines have been inhibited due to their probable category of mordant dyes with commercial carcinogenic character [46]. importance. They are applied in exhaustion dyeing onto wool or irregularly nylon fibers with high Direct dyes color fastness. The fibers are typically dyed by the Direct dyestuffs were recognized as the former afterchrome technique in which a chrome dye is category of synthetic dyestuffs to be applied on applied on fiber followed