Evaluation of the surface properties of 4-(Decyloxy) benzoic acid liquid crystal and its use in structural isomer separation

The selectivity of 4-(Decyloxy) benzoic acid (DBA) liquid crystal in surface adsorption region (303.2–328.2 K) and thermodynamic region (423.2 – 433.2 K) was investigated by inverse gas chromatography at infinite dilution (IGC-ID). The selectivity parameters of the structural isomer series named butyl acetate, butyl alcohol, and amyl alcohol series were calculated for the DBA using IGC-ID technique. Additionally, the surface properties including dispersive surface energy (gS D), free energy (DGA S), enthalpy (DHA S), and acidity-basicity constants were calculated with net retention volumes obtained from IGC-ID experiment results. When the DHA S and DGA S are constants, DBA surface was found to be an acidic character (KD/KA @ 0.89).     

Oxidation chemistry of 2'-deoxyadenosine at pyrolytic graphite electrode

The electrochemical oxidation of 2'-deoxyadenosine has been investigated in phosphate containing supporting electrolytes in pH range 2-10 at a pyrolytic graphite electrode by cyclic sweep voltammetry, spectral studies, controlled potential electrolysis and related techniques. The oxidation of 2'-deoxyadenosine occurred in a single well-defined oxidation peak (I(a)), over the entire pH range. The electrooxidation occurred by the loss of 6.0+/-0.5 e(-) per mole over the entire pH range. The kinetics of the decay of the UV-absorbing intermediates has been studied and found to follow pseudo first order kinetics having rate constant (k) in the range (5.7-7.7)x10(-4) s(-1). The major products of electrooxidation were separated by HPLC and characterized by GC-MS/MS, (1)H NMR and a tentative mechanism for electrooxidation of 2'-deoxyadenosine has been suggested.     

Synergistic effect of copolymers composition on the electrochemical,thermal, and electrical behavior of 5‐lithiosulphoisophthalic acid doped poly(aniline‐co‐2‐isopropylaniline): synthesis,characterization, and applications

The paper reports the synergistic effect of substituent, i.e. isopropyl group on electrical, thermal, and processability of polyaniline in the presence of 5‐lithiosulphoisophthalic acid (LiSIPA). The presence of substituent not only affects the electrochemical redox behavior of polyaniline but also brings changes in the optical and electronic properties of polyaniline. Evaluation of the copolymers as corrosion inhibitor for iron in 1.0 N HCl using electrochemical impedance spectroscopy and Tafel extrapolation method shows that the copolymers and homopolymer show corrosion inhibition efficiency ranging from 69 to 80% depending upon the composition of the copolymers. The copolymers doped with LiSIPA were soluble in organic solvents like methanol, ethanol, isopropanol, N‐methyl pyrrolidinone, and chloroform. The compositions of the copolymers were determined by ¹H NMR spectroscopy. The conductivity of the polymers was found to be in the order of 4.9 to 10^?3 S cm^?1 depending upon the comonomer ratios and concentration of dopant. Cyclic voltammetry of the copolymers shows a shift in peak potential value from 0.157 to 0.398 V when the monomer ratio of aniline to 2‐isopropylaniline in the polymerization reaction was changed from 0.9:0.1 to 0.5:0.5. The polymers were characterized by FTIR and UV‐visible spectroscopy, NMR, X‐ray diffraction, TGA, DSC, and cyclic voltammetry. Copyright © 2008 John Wiley & Sons, Ltd.