Synthesis, spectroscopic and computational investigation of N1,N4-bis(3-oxobutanoyl)benzene-1,4-dicarbohydrazide as a coupling component for azo dyes from waste poly(ethyleneterephthalate) bottle

Abstract

In order to contribute to the recycling of waste poly (ethylene terephthalate) (PET) in the industry; N1,N4-bis(3-oxobutanoyl)benzene-1,4-dicarbohydrazide (compound 1), a coupling component, was intended to be obtained from the condensation reaction between benzene-1,4-dicarbohydrazide (TPDH) and excess ethyl acetoacetate (EAA), and compound 1 were synthesized in good yield. Compound 1 was characterized by spectroscopic techniques (FTIR and NMR) and micro elemental analysis. Structural parameters, IR and NMR spectral data of compound 1 were obtained by DFT/B3LYP/6–311++G(d,p) method, considering two possible stable tautomeric forms as tetraketo and diketo-dienol. For detailed evaluation, theoretical IR and NMR data of compound 1 were compared with experimental ones. Results show that compound 1 predominantly exists in tetraketo form in solid state and DMSO. In this study, for the first time, a coupling component that can be used in the synthesis of azo dyes is obtained from TPDH, a degradation product of PET. This idea can lead to a significant contribution to saving raw materials in the industry and preventing environmental pollution caused by waste PET.