New benzalkoniumchloride derivatives ionic liquids (ILs) were synthesized in ≥ 97% yield and their inhibiting properties for the corrosion of carbon steel in formation water had been evaluated using chemical methods. The structures of the ILs compounds were investigated by elemental analysis, FT-IR spectrophotometer and 1H NMR spectroscopy. The designed molecular structure of ILs, with N atoms, makes it good corrosion inhibitor via the adsorption of ILs on the carbon steel surface to suppress both anodic and cathodic processes. The inhibition efficiency increases with increased ILs concentration.

Acid dissociation constants, pKa, of 2-pyrrolaldehyde phenylsulphonyl hydrazone, 1, and 2-thiophenealdehyde phenylsulphonyl hydrazone, 2, have been determined spectrophotometrically in ethanol-water media of various compositions over the temperature range 25℃ - 45℃. The obtained results were used in the calculation of the enthalpy, △H°, and the entropy, △S°, of the ionization processes. The slight variations observed in the pKa values of the thiophene compound compared to the pyrrol analogue revealed that neither of the two hetero atoms in the pyrrol or thiophene rings, of the two compounds, is involved in a hydrogen bond chelation. This conclusion was also confirmed through measurements of the dipole moment, IR and NMR spectra.

Ternary mixtures formed from components of the five series of unsymmetrical 1,4-phenylene bis-4-substituted benzoates (Ina--e), in which the substituent (X) alternatively changed from CH3O,CH3, Cl, NO2, and CN, respectively, while, within each homologous series, the length of the terminal alkoxy group varies between n=6, 8, or 14 carbons, were prepared and characterized for their mesophase behaviour. Transition temperatures of the mixtures prepared were measured by differential scanning calorimetry and the phases identified by polarized-light microscopy.

Binary mixtures of two types of 4-substituted benzoic acids covering the whole composition range were prepared by melting both components together stirring to give an intimate blend and then cooling to room temperature The mixtures prepared were characterized for their mesophase behavior by differential scanning calorimetry (DSC) and polarized-optical microscopy (POM) The first type of the acid is substituted with a small compact polar group that cover a wide range of polarity The other type of the acid is 4-alkoxy benzoic acid bearing an alkoxy (OCn H2n+1) group with varying chain length (n = 6-16) Binary phase diagrams were constructed whereby all phases observed were identified by POM The smectic C (SmC) mesophase was observed in all mixtures investigated while the nematic phase (N) was observed together with the SmC phase, only in mixtures possessing the acid homologues with n <= 12 carbons Complex formation was also supported by FT-IR spectroscopic measurements (C) 2010 Elsevier B V All rights reserved

Binary mixtures made from components of the four series of the molecular structure 4-CnH2n+1O–C6H4–COO–C10H6–NN–C6H4–X, in which both components bear the same alkoxy group (n=8, 10, 12, or 14) but of different substituent (X=CH3O, CH3, Cl, or NO2), were prepared and characterized for their phase behaviour. Transition temperatures of mixtures were measured by differential scanning calorimetry and identified by polarized-light microscopy. The dependence of the phase behaviour of mixed systems upon differences in the electronic nature of the terminal group, X, attached to both components as well as the length of the alkoxy group, was investigated from the phase diagrams constructed for the various binary combinations. The nematic order parameters are in accordance with the conclusions drawn.

Four series of 4-substituted phenyl-4-alkoxybenzoates were prepared in which one substituent is a terminal alkoxy group with the number of carbon atoms kept constant (at n=6, 8, 14, or 16), while the other terminal substituent (X) alternatively changed from CH3O, CH3, Cl, CN, and NO2. Compounds prepared were characterized by infrared spectroscopy and their mesophase stabilities investigated by differential scanning calorimetry and polarized-light microscopy. The results were discussed in terms of mesomeric, polarity, and polarizability effects. In all four series, the mesophase–isotropic transition temperatures (Tc) were successfully related to the polarizability anisotropy of bonds to the small compact substituent, X.