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This study aims to synthesize new disperse dyes based on novel pyrazolyl quinolinone derivatives EQ1 and EQ2 and evaluate their characteristics after dyeing them on a polyester fabric.

New dispersed dyes based on pyrazolyl quinolinone derivatives were prepared and confirmed by different analyses, such as infrared spectroscopy, elemental microanalysis and nuclear magnetic resonance spectroscopy. They were dyed on a polyester fabric. The characteristics of dyed polyester were determined by color measurements such as a*, b*, L*, C*, E, Ho, R% and color strength. The electronic structures of EQ1 and EQ2 in gaseous state were investigated using density functional theory/B3LYP/6-311++G (d, p) level of theory.

The suitability of the prepared dyestuffs for dyeing on polyester fabrics has been investigated. The study was concerned with comparing the contrasting depth of shade and levelness. The study was concerned mainly with dye uptake and color measurements at two different temperatures. The results showed that the exhaustion values of dyes inside the polyester at 130°C were higher than those obtained at conventional dyeing temperature (100°C). The exhaustion values of EQ2 were greater than those of EQ1 at 130°C with 2.2%, while the brightness of EQ2 was higher than that of EQ1 at the two investigated temperatures. The results of molecular orbital calculations show that the studied compounds are planar. In addition, the ionization potential of EQ1 was lower than that of EQ2. The results of the theoretical study helped in understanding the dyeing behavior of the investigated azo dyes.

The prepared disperse dyes based on pyrazolyl quinolinone derivatives could be used in textile dyeing of polyester on an industrial scale.

The purpose of this paper is to test the Natural Kermes dye (NKD) as a cheap and stable corrosion inhibitor for mild steel in 1.0 M HCl and its adsorption mechanism on the steel surface.

The inhibition action of NKD was studied using AC impedance, potentiodynamic polarization, scanning electron microscope (SEM) and UV-visible spectra techniques complemented with quantum study.

Here, the authors show that addition of NKD inhibits effectively the corrosion of steel in HCl solution via its adsorption on the steel surface. The inhibition efficiency of NKD increases with increase in its concentration and decreases with temperature. Potentiodynamic results revealed that NKD acts as a mixed–type inhibitor. Thermodynamic parameters for corrosion and adsorption process were obtained from the experimental data. Moreover, the experimental inhibition efficiencies were correlated with the electronic properties of NKD using density functional theory.

To the best of the authors’ knowledge, this is the first report showing the effect of NKD on the corrosion inhibition of steel.