Search results

1 – 10 of 232
Article
Publication date: 4 July 2016

G.H. Elgemeie, K.A. Ahmed, E.A. Ahmed, M.H. Helal and D.M. Masoud

The purpose of this study is to successfully implement microwave irradiation for the rapid synthesis of novel fluorescent dyes. The prepared dyes are then applied for…

Abstract

Purpose

The purpose of this study is to successfully implement microwave irradiation for the rapid synthesis of novel fluorescent dyes. The prepared dyes are then applied for printing of polyester and polyamide by silk screen printing process.

Design/methodology/approach

A series of new N′-(methylene)-2-imino-2H-chromene-3-carbohydrazide derivatives 3a–r were synthesised in excellent yield and high atom economy by the Knoevenagel condensation of salicylaldehyde derivatives 1 and cyano-N′-methyleneaceto-hydrazide derivatives 2 in the presence of piperidine catalyst. The optical properties of the synthesised compounds were recorded; all of the compounds were found to be fluorescent in 1, 4-dioxane solution; they all emitted blue light (440-460 nm). This work shows that the optical properties strongly depend on the nature of the substituent, and indicate which type of substituent is favourable for a given application. It confirms that iminocoumarin derivatives could lead to a new generation of fluorescent probes, prone to easy modification of their chemical structure. These synthesised dyes are used to print polyester and polyamide fabrics using synthetic thickener in the printing paste for silk screen technique.

Findings

The structures of synthesised dyes were established and confirmed for the reaction products on the basis of their elemental analysis and spectral data (MS, IR and 1H-NMR). The suitability of the prepared dyestuffs for traditional printing on polyester and polyamide fabrics has been investigated. The prints obtained using the synthesised dyes were found to possess high colour strength and excellent overall fastness properties but relatively low light fastness.

Research limitations/implications

The synthesised fluorescent dyes were prepared by a simple reaction process in microwave. The optical properties for obtained dyes show include the fact that it will have various important applications. In addition, they were used for printing synthetic fabrics and were found to have good results.

Practical implications

The new fluorescent dyes’ system has excellent printing properties. Also they are superior in terms of yield, purity, colour strength and fastness properties which may lend them valuable commercial production.

Originality/value

The result of this work aimed to define the scope and limitation of the procedures for the synthesis of novel iminocoumarin dyes via a simple and economic way.

Details

Pigment & Resin Technology, vol. 45 no. 4
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 6 November 2009

H.Z. Shams, Y.A. Youssef, F.A. Mohamed, M.M. El‐Zawahry, M.H. Helal and E.A. El‐Kharadly

The purpose of this paper is to evaluate the efficiency of modifying reactive azo dyes using pyrazolo[1,2‐a]pyrazole fused systems as the chromophoric moiety which could…

Abstract

Purpose

The purpose of this paper is to evaluate the efficiency of modifying reactive azo dyes using pyrazolo[1,2‐a]pyrazole fused systems as the chromophoric moiety which could satisfy many and varied criteria drawn from economic, synthetic, physicochemical and fastness properties.

Design/methodology/approach

Six novel heterocyclic disazo reactive dyes were prepared, containing monofunctional sulphatoethylsulphone (SES) and hetero‐bifunctional monochlorotriazine (MCT)/SES reactive groups. Dyes intermediates based on 4‐arylazo‐1,5‐dioxopyrazolo[1,2‐a]pyrazole chromophoric moieties are initially synthesised and coupled with two different diazonium salts having the aforementioned reactive groups, thus yielding the new target reactive dyes. The synthesised dyes are applied to cotton, wool and silk fabrics under the typical exhaust dyeing conditions and their dyeing properties were investigated.

Findings

The results assessed for dyeing indicate high‐quality dyeing properties. However, the heterobifunctional MCT/SES dyes showed higher exhaustion and fixation values, colour yields and fastness properties than those of the monofunctional SES dyes.

Research limitations/implications

The method developed provided a simple and practical procedure for producing fused pyrazolo[1,2‐a]pyrazole disazo chromophoric systems that afford valuable reactive dyes. In addition, the dyes intermediates based on 4‐arylazo‐1,5‐dioxopyrazolo[1,2‐a]pyrazole as well as their disazo counterparts could be applied as acid dyes to wool and silk.

Originality/value

The method for producing novel disazo reactive dyes could find numerous applications for affording a variety of reactive dyes with different binding linkages and structural reactivity. These could be valuable as reactive dyes with different colour shades.

Details

Pigment & Resin Technology, vol. 38 no. 6
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 1 June 2001

H.Z. Shams, M.H. Helal, F.A. Mohamed and S.A. Abd‐Elhafiz

A new series of the title pyrazole azo dye systems has been synthesized. The new dyes are applied on nylon and cellulose acetate fibers to give dyed fabrics with excellent…

Abstract

A new series of the title pyrazole azo dye systems has been synthesized. The new dyes are applied on nylon and cellulose acetate fibers to give dyed fabrics with excellent properties of colour intensity and fastness properties. The physical and spectral data of the investigated dyes are illustrated. The shifts of ultraviolet‐visible absorption maxima affected by the structural configuration of the pyrazole dye systems are investigated. The structural effects of the polyfunctionally substituted pyrazole dye systems on the intensity of colour and fastness properties of the dyed fabrics are discussed. The data of these studies are listed. The colour shades of the synthesized dyes on nylon and acetate fabrics are indicated.

Details

Pigment & Resin Technology, vol. 30 no. 3
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 12 September 2008

H.Z. Shams, M.H. Helal, I.M. Samir and R.M. Mohareb

The purpose of this paper is to evaluate the dyeing performance of newly designed and synthesised azo dye systems based on polyfunctionally substituted oxopyridine core…

Abstract

Purpose

The purpose of this paper is to evaluate the dyeing performance of newly designed and synthesised azo dye systems based on polyfunctionally substituted oxopyridine core for improved dyeing when applied to synthetic fibres.

Design/methodology/approach

For improved dyeing qualities, various azo dye systems were synthesised based on polyfunctionally substituted oxopyridine core as the coupling component. The heterocyclic moiety was coupled with diazotized aromatic amines or diazotized tetrahydrobenzothiophenes to afford the respective azo or hydrazono systems. Other counterparts were obtained via treatment with different reagents. The structure of the novel systems was elucidated based on elemental analysis and spectral data. Dyeing performance, electronic spectra and optical properties were characterised based on UV and K/S measurements. Fastness properties were also evaluated.

Findings

The novel systems were designed so that the functionalities located on the heterocyclic core afforded structure modification that led not only to good dispersion but also to improved adherence on the fibre. The sites of location led to construction of a resonating system with higher electron mobility and higher absorption maxima.

Research limitations/implications

The azo dyes, used in the present context were synthesised via a step‐wise pathway leading to different systems of dyes. In addition, the variations in substituents and sites of location on the heterocyclic core could also be studied.

Practical implications

The novel azo dye systems based on polyfunctionally substituted oxopyridine core provide a simple practical access to a series of azo dyes with improved dyeing properties. The availability of starting materials, the simplicity and efficiency for production in good yields and high‐purity can lead to valuable achievements for commercial production.

Originality/value

The designed and synthesised azo dye systems could find numerous applications as disperse dyes in the fields of dyeing, printing and surface coating. Moreover, the systems could find applications as reactive dyes for wool, silk and cellulosic fibres.

Details

Pigment & Resin Technology, vol. 37 no. 5
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 7 November 2008

M.H. Helal, G.H. Elgemeie and D.M. Masoud

This paper's aim is to evaluate the dyeing performance of newly designed azo dye system based on thiazole substituted for improved dyeing when applied to synthetic fibres.

Abstract

Purpose

This paper's aim is to evaluate the dyeing performance of newly designed azo dye system based on thiazole substituted for improved dyeing when applied to synthetic fibres.

Design/methodology/approach

For improved dyeing qualities, various azo dye systems were synthesised based on polyfunctionally substituted thiazole as the coupling component. The heterocyclic moiety was coupled with diazotised aromatic amines to afford the respective azo or hydrazono systems. The structure of the novel systems was elucidated based on elemental analysis and spectral data. Dyeing performance, electronic spectra and optical properties were characterised based on UV and K/S measurements. Fastness properties were evaluated.

Findings

The novel systems were designed so that the functionalities located on the heterocyclic ring afforded structure modification that led not only to good dispersion but also to improved adherence on the fibre. The location of the sites led to constructing a resonating system with higher electron mobility and higher absorption maxima.

Research limitations/implications

The azo dyes, used in the present context were synthesised via a step‐wise pathway leading to new dyes. In addition, the variations in substituents and location of sites on the heterocyclic core could also be studied.

Practical implications

The novel azo dye systems based on polyfunctionally substituted thiazole provided a simple practical access to a series of azo dyes with improved dyeing properties. The availability of starting materials, the simplicity and efficiency to production in good yields and high purity lead to valuable achievements for commercial production.

Originality/value

The designed azo dye systems could find numerous applications as disperse dyes in the fields of dyeing, printing and surface coating. Moreover, the systems can find applications as reactive dyes for wool, silk and cellulosic fibres.

Details

Pigment & Resin Technology, vol. 37 no. 6
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 1 October 2001

M.H. Helal

Two series of azo dye systems are considered, namely, 2‐amino‐arylazo‐4‐phenylthiazole axo dye systems 4a,b,c,d,e, and 3‐methyl‐1‐phenylpyrazolone azo dye systems 8a‐d…

Abstract

Two series of azo dye systems are considered, namely, 2‐amino‐arylazo‐4‐phenylthiazole axo dye systems 4a,b,c,d,e, and 3‐methyl‐1‐phenylpyrazolone azo dye systems 8a‐d. The shifts of ultraviolet‐visible absorption maxima affected by the structural configuration of the thiazole and pyrazole dye systems are investigated. The structural effects of the polyfunctionaIly substituted thiazole and pyrazole dye systems on the intensity of colour and fastness properties of the dyed fabrics are also discussed. The data of these studies are listed.

Details

Pigment & Resin Technology, vol. 30 no. 5
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 1 April 2001

H.Z. Shams, M.H. Helal and F.A. Mohamed

Three series of azo dye systems are considered, namely, 5‐oxo‐2‐pyrazoline azo dye systems 9 a‐d,1‐oxo‐pyrazolo pyrazole azo dye systems 10 a, b, c, e, 11 a, b, c, e, 12…

Abstract

Three series of azo dye systems are considered, namely, 5‐oxo‐2‐pyrazoline azo dye systems 9 a‐d,1‐oxo‐pyrazolo pyrazole azo dye systems 10 a, b, c, e, 11 a, b, c, e, 12 a, b, c, e, 13 a‐d and 6‐oxo‐pyranopyrzole azo dye systems 14 a‐d. The shifts of ultraviolet‐visible absorption maxima affected by the structural configuration of the pyrazole dye systems are investigated. The structural effects of the polyfunctionally substituted pyrazole dye systems on the intensity of colour and fastness properties of the dyed fabrics are also discussed. The data of these studies are listed. Colour shades of the synthesized dyes on nylon and acetate fabrics are indicated.

Details

Pigment & Resin Technology, vol. 30 no. 2
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 11 January 2008

M.H. Helal, G.H. Elgemeie, M.A. El‐kashouti and K.A. El‐zaher Ahmed

The purpose of this paper is to synthesise new heterocyclic disperse azo dyes based on benzothiazapine moiety and their printability on synthetic fabrics.

Abstract

Purpose

The purpose of this paper is to synthesise new heterocyclic disperse azo dyes based on benzothiazapine moiety and their printability on synthetic fabrics.

Design/methodology/approach

Ethyl cyanoacetate was refluxed with aniline derivatives for 3 h to form cyanoacetanilides which coupled with different diazonium salts. The products obtained were cyclised with 2‐amino thiophenol to form arylazo benzothiazapine derivatives. The structures of the new dyes were characterised by micro‐analysis as well as IR, 1H NMR and 13C NMR. Printing pastes containing the dyestuffs prepared and thickened with sodium alginate were used for printing synthetic fabrics using either transfer printing or traditional screen printing.

Findings

New heterocyclic monoazo dyes derived from benzothiazabine moiety were obtained by the coupling of diazotised aniline derivatives with ethylcyanoacetate anilides followed by cyclisation with 2‐amino thiophenol. The use of synthesised dyes for transfer‐ or screen‐printing polyester and nylon 6 fabrics has been studied. The synthesised dyes which contain electron withdrawing substituents (NO2) in the phenyl ring attached to the azo groups and electron‐donating (OCH3) group on the other phenyl ring exert a bathochromic effect.

Research limitations/implications

Synthesis of azo dyes containing benzothiazapine moiety has never been reported in textile printing.

Practical implications

Production of simple and less costly dyes.

Originality/value

Synthesis of aryl azo benzothiazapine dyes by a simple method and application in printing of synthetic fabrics.

Details

Pigment & Resin Technology, vol. 37 no. 1
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 18 September 2007

M.H. Helal, G.H. Elgemeie and D.M. Masoud

This paper aims to synthesize some new heterocyclic disperse azo dyes and their application in dyeing of polyester and polyamide fabrics.

Abstract

Purpose

This paper aims to synthesize some new heterocyclic disperse azo dyes and their application in dyeing of polyester and polyamide fabrics.

Design/methodology/approach

Pyrazolopyrimidine derivatives containing arylazo function by the reaction of 3,5‐ diaminopyrazole with ketene dithioacetals were prepared. The prepared dyestuffs are established using elemental analysis, IR measurements, 1H‐NMR and Mass spectra.

Findings

2,5‐diamino‐3‐arylazo‐N‐aryl‐6‐carboxamide‐7‐methylthio‐pyrazolo[1,5‐a]pyrimidine have been synthesized by the simple method. The dyed fabrics have a very good (4‐5) to excellent (5) results toward washing, perspiration, and rubbing fastness properties. The dyes are superior in terms of preparation and fastness properties.

Research limitations/implications

The disperse azo dyes used in this paper were synthesized via a step‐wise pathway leading to the new azo dyes. In addition, the variations in substituents and sites of location on the heterocyclic moiety could also be studied.

Practical implications

The new azo dye systems based on substituted pyrazolopyrimidine provided a series of azo dyes with improved dyeing properties. The dyes are superior in terms of yield, purity, colour strength, and fastness properties and will lead to valuable achievements for commercial production.

Originality/value

The synthesized disperse azo dyes are superior in terms of preparation, yield, purity, and fastness properties.

Details

Pigment & Resin Technology, vol. 36 no. 5
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 4 July 2008

M.H. Helal, G.H. Elgemeie, M.A. El‐kashouti, M.M. ElMolla, H.S. Elsayad and K.A. Ahmed

The purpose of this paper is to synthesise some disperse dyes containing a reactive group and study their applications on polyamide and wool printing by heat transfer and…

Abstract

Purpose

The purpose of this paper is to synthesise some disperse dyes containing a reactive group and study their applications on polyamide and wool printing by heat transfer and screen printing.

Design/methodology/approach

To prepare these dyes, arylhydrazones of acetylacetone were reacted with cyanothioacetamide in boiling ethanolic sodium ethoxide. The resultant salt was collected by filtration and dried, then the salt was dissolved in ethanol and reacted with chloroacetylchloride with stirring for 3 h, where chloroacetylechloride was added dropwise. The final precipitated product was collected by filtration and crystallised with an appropriate solvent. These prepared dyes were used to print polyamide and wool fabrics by using synthetic thickener in the printing paste for all techniques.

Findings

The structure of the synthesised dyes were established and confirmed for the reaction products on the basis of their elemental analysis and spectral data (MS, IR and 1H‐NMR). The suitability of the prepared dyestuffs for either heat transfer printing or traditional printing on nylon 6 and wool fabrics was investigated. The prints obtained from dyes possess high‐colour strength as well as excellent overall fastness properties.

Research limitations/implications

The synthesised heterocyclic reactive disperse azo dyes were prepared from the reaction of arylhydrazones of acetylacetone and thiocyanoacetamide to form the corresponding pyridinethione salts which underwent further reaction with chloroacetylchloride. The obtained dyes were utilised in preparing a paste for polyamide and wool fabric printing. In addition, both of the variation of the substituents on the synthesised dyes and the fastness properties were also studied.

Practical implications

The synthesis and use of reactive disperse dyes provide practical solution to over come the low fastness on polyamide and wool, when they are printed with disperse dyes only.

Originality/value

The result of the work aimed to define the scope and limitation of the authors' procedures for the synthesis of novel reactive disperse azo dyes to improve the low‐fastness properties of polyamide and wool, the dyes were synthesised in a simple way.

Details

Pigment & Resin Technology, vol. 37 no. 4
Type: Research Article
ISSN: 0369-9420

Keywords

1 – 10 of 232