Novel benzothiazapine azo dyes: synthesis, characterisation and printing properties

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.

Citation

Helal, M.H., Elgemeie, G.H., El‐kashouti, M.A. and El‐zaher Ahmed, K.A. (2008), "Novel benzothiazapine azo dyes: synthesis, characterisation and printing properties", Pigment & Resin Technology, Vol. 37 No. 1, pp. 28-36. https://doi.org/10.1108/03699420810839684