Pinki B. Punjabi

Synthesis and Characterization of Conducting Polyanilines via Catalytic Oxidative Polymerization

Polyanilines have been prepared by catalytic oxidative polymerization of aniline in an acidic solution using H2O2 as an oxidant and ferrous sulfate as a catalyst in presence of light by photo-Fenton process. The structures of polyanilines were elucidated by UV-vis, Fourier transform infrared, and nuclear magnetic resonance spectroscopy, which confirmed the presence of benzenoid and quinoid rings in the polyanilines. Molecular weight and specific surface area were determined by gel permeation chromatography and BET analysis. The differential scanning calorimetry results and two-probe conductometry studies showed that samples had good thermal stability and electroactivity.

Synthesis, Characterization, and Antimicrobial Properties of p-Chloroacetophenone Oxime-Based Furan Resins

A copolymer resin, p-chloroacetophenone oxime-furfuraldehyde (CAOFU), and a terpolymer resin, p-chloroacetophenone oxime-formaldehyde-benzoic acid (CAOFUBA), were synthesized in the presence of hydrochloric acid as catalyst. The structures of copolymer and terpolymer were established by FT-IR and 1H NMR techniques. Molecular weight and polydispersity index were determined by gel permeation chromatography. The thermal stability was evaluated by thermogravimetric analyses (TGA). Softening temperatures (Ts) of these polymers were obtained from differential scanning calorimetry (DSC). All the synthesized polymers have shown reasonably good antimicrobial activities.

Role of copper pyrovanadate as heterogeneous photo-Fenton like catalyst for the degradation of neutral red and azure-B: An eco-friendly approach

The heterogeneous photo-Fenton like process is a green chemical pathway. It has an edge over conventional Fenton and photo-Fenton processes as it does not require the removal of ferrous/ferric ions in the form of sludge. We prepeared copper pyrovanadate or Volborthite (Cu3V2(OH)2O7∙2H2O) composite photocatalyst by wet chemical method. The photocatalyst was characterized by SEM, XRD, IR, TGA/DSC, EDX and BET. Experiments demonstrated that catalyst could effectively catalyze degradation of neutral red and azure-B in presence of H2O2 in visible light. Moreover, the photo-Fenton-like catalytic activity of Cu3V2(OH)2O7∙2H2O was much higher than CuO and V2O5, when used alone as photocatalyst. The effect of variation of different parameters, i.e., pH, amount of photocatalyst, concentration of dye, amount of H2O2 and light intensity was also investigated. The degradation was well fitted under pseudo-first-order reaction with a rate constant of 2.081×10−4 sec−1 and 3.876×10−4 sec−1 for neutral red and azure-B, respectively. Quality parameters of dye solutions before and after photo-Fenton degradation were also determined. A tentative mechanism involving •OH radical as an oxidant has been proposed. The high catalytic activity may be due to the Cu3V2(OH)2O7∙2H2O shell, which not only increased the surface hydroxyl groups, but also enhanced the interfacial electron transfer. The catalyst has been found to possess good recyclability.

Cadmium sulfide photocatalysed reduction of malachite green by ascorbic acid and EDTA as reductants

The photoreduction of malachite green in presence of CdS as photocatalyst and ascorbic acid/EDTA as reductants has been carried out. The effect of different parameters like pH, concentration of malachite green, reductants, amount of semiconductor and light intensity on the rate of photocatalytic reaction has been studied. On the basis of observed data, a tentative mechanism for the photoreduction of malachite green has been proposed.

Spectral and thermal characterization of halogen-bonded novel crystalline oligo(p-bromoacetophenone formaldehyde).

A novel oligomer p-bromoacetophenone-formaldehyde (OPBAF) was prepared by condensation polymerization in the presence of an acid as catalyst. It was characterized by FT-IR, NMR, pyrolysis GC/MS, XRD, GPC, and TG-DTG. The crystallographic parameters and space group for hexagonal OPBAF were a = b = 2.0810 Å and c = 9.2340 Å and P3̅m1, respectively. The degradation activation energy of the oligomer was studied by the Kissinger method. The kinetic parameters were also obtained. Halogen bonding interactions in the crystalline oligomers are identified between halogen···carbonyl and halogen···halogen. Little correlation was found in the halogen bonding motifs exhibited as a function of bromine present in this oligomer, and a unique bifurcated Br···Br/Br···O═C halogen bonding synthon was identified. This newly developed oligomer may be used as an interesting material for the development of 3D-designed structural products.

Synthesis and Characterization of Functionalized Polyaniline Having Methyl Violet as Pendant Groups

Methyl violet–substituted polyaniline is prepared by oxidative polymerization of aniline in an aqueous acidic media using tosic acid as dopant and ammonium persulphate as oxidant. Substitution of methyl violet (dye moieties) on polyaniline backbone takes place in the presence of butyl lithium. The structures of methyl violet–substituted polyanilinewas elucidated by Fourier transform infrared (FT-IR), fluorescence spectra, XRD and differential scanning calorimetery (DSC). Molecular weight is determined by gel permeation chromatography (GPC) and viscosity method. Conductivity and band gap of methyl violet–substituted polyaniline was computed by a two-probe conductometer.

Heterogeneous photo-Fenton-like catalysts Cu2V2O7 and Cr2V4O13 for an efficient removal of azo dye in water

Abstract This work deals with the degradation of non-biodegradable azo-dye (Evans blue) by the heterogeneous photo-Fenton-like process using copper pyrovanadate (Cu2V2O7) and chromium tetravanadate (Cr2V4O13) as catalysts, which have been prepared by wet chemical method. These catalysts were characterized by different techniques such as scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and Brunauer–Emmett–Teller surface area analysis. The effect of various parameters such as initial pH, concentration of dye, amount of catalyst, amount of H2O2, and light intensity on the reaction rate has also been studied. Photodegradation efficiency was found 77.78 and 79% for copper pyrovanadate (Cu2V2O7) and chromium tetravanadate (Cr2V4O13), respectively. A tentative mechanism involving ·OH radicals as an oxidant for the degradation of dye has also been proposed. The observations revealed that the rate of photo-Fenton-like degradation of dye follows pseudo-first-order kinetics.

Preparation and Characterization of Polyanilines Bearing Rhodamine 6-G and Azure B as Pendant Groups

Rhodamine 6G and Azure B substituted polyanilines are prepared by oxidative polymerization of aniline in an aqueous acidic media using hippuric acid and tosic acid as dopant and ammonium per sulphate as oxidant. Substitution of rhodamine 6G and azure B on polyaniline backbone takes place in presence of butyl lithium. The structures of rhodamine 6G and azure B substituted polyanilines was elucidated by UV–visible spectroscopy, IR spectroscopy,1H nuclear magnetic resonance (1H NMR), 13C nuclear magnetic resonance (13C NMR). Molecular weight and specific surface area were determined by gel permeation chromatography (GPC) and Brunauer–Emmett–Teller (BET) analysis. Conductivity of rhodamine 6G and azure B grafted polyanilines were computed by two probe conductometer.

Synthesis of dye-substituted polyanilines and study of their conducting and antimicrobial behavior

Abstract Conducting and antimicrobial properties of chemically synthesized polyanilines was found to be affective by varying the dye moieties. The temperature dependence of AC conductivity was studied by two-probe method to learn about the conduction behavior of the synthesized compounds. The conductivity of the dye-substituted polyanilines was found to be in the range of 10−3 S/cm. For the study of antimicrobial behavior of the synthesized dye-substituted polyanilines, different micro-organisms, namely, the bacteria Escherichia coli (MTCC 442), Pseudomonas aeruginosa (MTCC 441), Staphylococcus aureus (MTCC 96), and Staphylococcus pyogenus (MTCC 443) and fungal strains Candida albicans (MTCC 227), Aspergillus niger (MTCC 282), and Aspergillus clavatus (MTCC 1323), were chosen based on their clinical and pharmacological importance. Antimicrobial properties of dye-substituted polyanilines show very good results as compared to polyanilines and dyes individually.

Copper pyrovanadate as an effective photo-Fenton-like catalyst for degradation of methylene blue

Visible light-based photo-Fenton-like catalytic performance of Cu3V2 (OH)2O7·2H2O is investigated using methylene blue as the target pollutant.