Determination of water content in dimethyl sulfoxide/N,N-dimethyl formamide and methanol content in ethanol by solvatochromism of azo dye, 2-(tert-butyl)-4-methoxy-6-(naphthalen-1-yldiazenyl) phenol.

A novel 2-(tert-butyl)-4-methoxy-6-(naphthalen-1-yldiazenyl)phenol (NAP) was synthesized by coupling reaction of 2-tert-butyl-4-methoxyphenol with diazotized naphthylamine as diazo component. The azo dye was characterized by NMR, FT-IR and UV-vis spectroscopic techniques. The visible spectrum of NAP was recorded in different solvents and at different pHs. NAP exhibited a large wavelength shift with increasing solvent polarity, showing significant color change over a wide range in different solvents. The determination of water content in organic solvents miscible with water such as dimethyl sulfoxide (DMSO)/N,N-dimethyl formamide (DMF) and methanol content in ethanol, which is also a common mixture were investigated with NAP which is azo dye. The present reported solvatochromic compound for the determination of water content in DMSO/DMF and methanol content in ethanol showed a fairly wide linear range compared to some previously reported solvatochromic compounds in the literature. In addition, the solvatochromism of NAP allows the determination of methanol content in ethanol, which has caused many deaths, with a fast, cheap and easy method.

A novel approach to redox active polymers: Decolorization of methylene blue by heterogeneous reduction with redox active azo polymer.

The existing reducing agents used in the literature to decolorization of methylene blue are soluble in water and the reduction process is carried out in a homogeneous redox reaction medium. After the decolorization process, the reducing agents and its by-products remain in a homogeneous redox reaction medium. Many of these reducing agents are toxic and cause chemical pollution of textile wastewater. Therefore, there is a need for reducing agents that can be mixed heterogeneously with water from which the reducing agent can be easily removed from a redox reaction medium. For this purpose, water-insoluble redox active azo polymer was synthesized from redox active 1,4-dihydroxybenzene and p-phenylenediamine. The synthesized redox active azo polymer was used for decolorization of methylene blue by heterogeneous reduction and various kinetic parameters were investigated for this redox reaction. At the same time, the investigated results of azo polymer and monomer (1,4-dihydroxybenzene) were compared.

Intercalation of pyrazolone-based oxalamide metal complexes into Na-montmorillonite for catalytic liquid-phase oxidation of phenol using H2O2.

The intercalation of pyrazolone-based oxalamide metal complexes into Na-montmorillonite (Na-MMT) for catalytic liquid-phase oxidation of phenol using H2O2 was undertaken by a flexible ligand method using metal ions including Mn(II), Zn(II), and Sn(II). First, the metal ions were exchanged with the sodium ions of Na-MMT, and then these metal ions were complexed with a new pyrazolone-based oxalamide ligand. The intercalated metal complexes were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, elemental analysis, and thermogravimetric analysis. Phenol was successfully oxidized by heterogeneous catalysts based on Mn(II), Zn(II), and Sn(II) pyrazolone-based oxalamide complexes intercalated into Na-MMT. These heterogeneous catalysts catalyze the liquid-phase oxidation of phenol using H2O2 to catechol as the major product and hydroquinone and benzoquinone as the minor products. The Mn(II) and Zn(II) complexes intercalated into Na-MMT showed better activity than the Sn(II) complex intercalated into Na-MMT and the reaction without the catalyst. It has been shown that some metal ion complexes intercalated into Na-MMT are active catalysts for liquid-phase oxidation of phenol with hydrogen peroxide.