Nonionic Surfactants from Recycled Poly(ethylene terephthalate) as Corrosion Inhibitors of Steel in 1 M HCl

Recycled poly(ethylene terephthalate) (PET) can be modified to produce nonionic surfactants. Recycling of PET waste was carried out in presence of triethanolamine and manganese acetate as catalyst. The produced oligomers were reacted with stearic acid and polyethylene glycol, PEG, which have different molecular weights 400, 1,000, and 4,000. The inhibition of corrosion of steel in 1 molar hydrochloric acid solution in the presence of the prepared surfactants is studied by weight loss and electrochemical polarization measurements. The polarization curves indicate that these compounds act as mixed‐type inhibitors. The inhibition efficiency increases with the increase of inhibitor concentration to reach their critical micelle concentrations. The temperature effect on the corrosion behavior of steel in 1 M HCl with and without surfactants is studied in the temperature range from 308 to 343 K. The adsorption of inhibitors on the steel surface is found to increase with increasing the temperature. From the adsorption isotherm, some thermodynamic data for the adsorption process are calculated and discussed.     

Low-temperature formation of cubic β-PbF2: precursor-based synthesis and first-principles phase stability study

A precursor-based approach to the cubic β-phase of PbF(2) was developed and allowed the preparation of this high-temperature phase well below the temperature for transition from the orthorhombic α- to the cubic β-phase. The formation of β-PbF(2) from the molecular precursors Pb[Se(C(6)H(2)(CF(3))(3))](2) and Pb(C(6)H(2)(CF(3))(3))(2) is facilitated by the presence of several short PbF contacts in these molecules. The cubic form of PbF(2) was obtained as macroscopic crystals as well as nanoparticulate powder. Its formation at relatively low temperature suggested a theoretical re-investigation of the phase stabilities of the two polymorphs. The theoretical results from the Kohn-Sham density functional theory indicate that the energy content for the β-phase is slightly lower than the one for the α-phase, by 0.5-1.7 kJ mol(-1) depending on the density functional used (zero-point vibrational energy correction included).     

Synthesis and structural studies of (2 E ,3 E ,6 R ,9 E ,11 E )-6-isopropenyl-3,6,10-trimethyl-5,8-dioxa-4,9-diazadodeca-3,9-diene-2,11-dione dioxime, ligand and its Mono-, homo, and heterodinuclear copper(II)/nickel(II) complexes

This article describes the synthesis of a new (2E,3E,6R,9E,11E)-6-isopropenyl-3,6,10-trimethyl-5,8-dioxa-4,9-diazadodeca-3,9-diene-2,11-dione dioxime (H₂hmdm), and its mono-, homo, and heterodinuclear copper(II)/nickel(II) complexes. Elemental analyses, stoichiometric and spectroscopic data of the metal complexes indicated that the metal ions are coordinated to the oxime and imine nitrogen atoms (C=N). The Cu(H₂hmdm), molecule coordinates to the second copper(II) ion through the oximate oxygens to afford a binuclear structure doubly bridged by the oximate groups in the cis arrangement. In the dinuclear complexes, in which the first Cu^II ion was complexed with nitrogen atoms of the oxime and imine groups, the second Cu^II ion is ligated with the 1,10-phenanthroline nitrogen atoms. Ligand and its mononuclear copper(II), homo and heterodinuclear copper(II)–nickel(II) complexes of (H₂hmdm) were characterized by elemental analyses, magnetic moments, ¹H-n.m.r. and ¹³C-n.m.r., i.r., and mass spectral studies. The data support the proposed structure of H₂hmdm and its complexes.     

Synthesis and Structural Studies of 2-(hydroxyimino)-1-methylpropylideneamino-phenyliminobutan-2-one Oxime, Ligand and its Complexes with Cu(II) and Ni(II)

A new ligand incorporating a dioxime moiety, (2E,3E)-3-[(2-{[(1E,2E)-2-(hydroxyimino)-1-methylpropylidene]amino}phenyl)imino]butan-2-one oxime, (H₂Phmdo) (3) has been prepared by reacting 2,3-butanedionemono-{O-[4-(1-methyl-2-oxo-propylideneaminooxy)-2,3-bis-(1-methyl-2-oxo-propylideneaminooxy-methyl)-but-2-enyl]-oxime} (2) with 1,2-phenylenediamine. Mono-, di- and trinuclear copper(II) and/or nickel(II) complexes of H₂Phmdo were characterized by elemental analyses, magnetic moments, ¹H-n.m.r. and ¹³C-n.m.r., i.r. and mass spectral studies. The mononuclear copper(II) and nickel(II) complexes of H₂Phmdo were found to have a 1:1 metal:ligand ratio. Elemental analyses, stoichiometric and spectroscopic data of the metal complexes indicated that the metal ions are coordinated to the oxime and imine nitrogen atoms (C=N). In the dinuclear complexes, in which the first Cu^(II) or Ni^(II) ion was complexed with nitrogen atoms of the oxime and imine groups, the second Cu^(II) ion is ligated with dianionic oxygen atoms of the oxime groups and are linked to the 1,10-phenanthroline nitrogen atoms. The data support the proposed structure of H₂Phmdo and its complexes.     

Synthesis,spectroscopic properties,crystal structures,antioxidant activities and enzyme inhibition determination of Co(II) and Fe(II) complexes of Schiff base

Research on Chemical Intermediates - Considering the importance of metal complexes in the development of medical science, two different Schiff base Fe(II) and Co(II) metal complex compounds were...