The design and synthesis of the new amino acid Schiff base, N-(2-hydroxy-1-naphthalidene)phenylglycine (Hhnpg) has been described along with the single crystal X-ray crystallographic studies. Copper(II), nickel(II), cobalt(II), manganese(II) and zinc(II) complexes of Hhnpg were synthesized for the first time, and were characterized on the basis of elemental analysis, conductivity measurements, spectral (i.r., 1 H-n.m.r., u.v.-vis., e.p.r.), magnetic and thermal studies. The i.r. spectral studies of all the complexes exhibit a similar feature about the ligating nature of the ligand to the metal ions and reveal that the ligand has coordinated through the carbonyl oxygen, azomethine nitrogen and deprotonated hydroxyl oxygen. The conductance data of the complexes suggest them to be nonelectrolytes. The microbial activity of the ligand and the complexes was investigated.

Three types of polyimide membranes viz., Matrimid, Kapton and P84, were prepared by solution casting and solvent evaporation method to study the permeation of CO 2 and CH 4 gases. Barrier properties were investigated as a function of feed pressure for pure gases and feed composition for the binary mixtures of CO 2 and CH 4 . Kapton polyimide, prepared by imidization of polyamic acid, showed an increase in permeability, but reduction in selectivity, due to the occurrence of plasticization at higher feed CO 2 concentrations. Matrimid was found to exhibit the highest permeability and was studied in greater detail, due to the feasibility in its scale-up into a hollow fiber modular configuration for commercial application. Matrimid was characterized by Fourier transform infrared (FTIR) spectroscopy and X-ray diffractometry (XRD) to assess the intermolecular interactions and to understand the separation profiles. The effect of feed flow was evaluated by studying the permeation behavior of flat sheet membrane in dead-end operation mode with the hollow fiber module operated in crossflow feed mode. For pure gases, Matrimid hollow fiber membrane exhibited a CO 2 permeability of 12.7 Barrers with a CO 2 /CH 4 selectivity of 40 at the feed pressure of 20 bar. At the same pressure, for binary mixture feed of 5 mol % CO 2 in methane, the module gave a permeability of 7.4 Barrers with a selectivity of 21. The total binary mixture permeability was determined at the feed CO 2 concentrations varying from 0 to 20 mol % to demonstrate the preferential sorption of CO 2 in Matrimid membrane.

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Naphthenic acid is a generic name used for all the organic acids present in crude oils. The quantitative determination of naphthenic acid number (NAN) is an essential parameter for petroleum refineries to evaluate corrosive properties of crude oils prior to their processing. Currently, most of the refineries are using total acid number (TAN) as a measure of corrosivity of crudes during their selection, valuation, and processing. Some of the organic molecules are being used as corrosion inhibitors to reduce corrosion in refinery process units, and the dosage of the same depends on the total acid number as it has been understood from the studies that acid inhibitors form a protective layer on the surface of the pipes and thus reduces the corrosion due to acids present in crude oil. TAN measurement by titration overestimates the acid number as each and every molecule like thiols and phenols etc. that are titratable by alkali are also included in the calculation and that causes the improper estimation of the addition of corrosion inhibitors. To get a better refinery margin in the present economic scenario, optimization of the addition of corrosion inhibitors is very much essential and thus accurate measurement of NAN is a primary concern. Hence, we present a quick and efficient mid-Fourier transform infrared (FTIR) spectroscopic method for the determination of NAN using a variable path length liquid cell with calcium fluoride windows. Two distinct photon absorption bands in the region of 1680 to 1800 cm–1 were observed during the spectral measurement and are due to the formation of monomeric and dimeric forms of carbonyl (CO) group of carboxylic acids, and hence both are considered for the quantification. The method is applicable even to highly volatile crude oils that are not measurable by the normal attenuated total reflectance (ATR)-FTIR technique. This article also presents the effect of solvents, hydrogen bonding, formation of monomer and dimer, etc. Currently, this method is being applied for the determination of NAN for crude oils and straight run vacuum gas oil (VGO) samples as they contain either negligible or no carbonyl compounds other than carboxylic acids that interfere in the region of interest.

A new tetradentate NOOO-donor ligand, N-(salicylidene)nitrosophenylglycine (H 2 snpg) has been designed, synthesized and structurally characterized. Copper(II), nickel(II), cobalt(II), manganese(II) and zinc(II) complexes of H 2 snpg have been prepared for the first time. The authenticities of the ligand and its metal complexes have been established on the basis of elemental analyses, molar conductance measurements, magnetic properties, spectral (i.r., 1 H-n.m.r., u.v.-vis. and mass) studies. The i.r. spectral studies of all the complexes exhibit a similar feature about the ligating nature of the ligand to the metal ions and revealed that the ligand has coordinated through the carbonyl oxygen, azomethine nitrogen, nitroso oxygen and deprotonated hydroxyl oxygen. The molar conductance data suggest them to be non-electrolytes. The antimicrobial activity of all the compounds was studied against Escherichia coli, Bacillus cirroflagellosus, Aspergillus niger and Candida albicans. All the complexes have shown a moderate to high fungal activity compared to the ligand.

A new Schiff base, 2,6-diacetylpyridine bis(2-hydrazinobenzothiazole) (DPHB), has been designed, and synthesized by the condensation of 2,6-diacetylpyridine with 2-hydrazinobenzothiazole, and structurally characterized. Copper(II), cobalt(II), nickel(II), manganese(II), zinc(II), cadmium(II) and oxovanadium(IV) complexes of DPHB have been synthesized for the first time. Their structures have been elucidated on the basis of elemental analyses, conductance measurements, magnetic properties, spectral (i.r., 1 H-n.m.r., u.v.-vis., e.p.r. and FAB-mass) and thermal studies. The complexes exhibit an octahedral geometry around the metal centre. The conductance data of all the complexes suggest them to be 1:1 electrolytes. The X-band e.p.r. spectra of the copper(II) and oxovanadium(IV) complexes in the polycrystalline state at room (300 K) and liquid nitrogen temperature (77 K) were recorded and their salient features are reported. Thermal stabilities of the manganese(II) and zinc(II) complexes have been studied.