Synthesis of new 5‐arylazo‐3‐cyano‐4,6‐dimethyl‐2‐acetylchloridethiopyridine reactive disperse dyes and their applications in textile printing

Abstract

PurposeThe 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/approachTo 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.FindingsThe 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/implicationsThe 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 implicationsThe 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/valueThe 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.