Synthesis and Characterization of Poly(methyl acrylate)-grafted-Sodium Salt of Partially Carboxymethylated Tamarind Kernel Powder

Ceric ammonium nitrate (CAN)-initiated graft copolymerization of methyl acrylate (MA) onto sodium salt of partially carboxymethylated tamarind kernel powder (Na-PCMTKP, DS = 0.15) was studied in an aqueous medium by solution polymerization technique. The growth of the graft reaction was monitored gravimetrically. The role of various synthesis variables on the grafting yields was examined to achieve the maximum graft yields (%G = 278.27, %GE = 94.38, %Hp = 5.62) and the influence of the synthesis variables in the graft copolymerization has been discussed. The reactivity of methyl acrylate (MA) towards graft copolymerization was compared with that of acrylonitrile (AN) on the basis of the results obtained from the earlier studies and plausible explanation was furnished for the observed reactivity of both the monomers towards grafting. The evaluated optimized reaction conditions were utilized to study the effect of reaction medium on grafting and it was found that reaction medium plays an important role in graft copolymerization. In order to ascertain the grafting, characterization of the samples made by FTIR, TGA and SEM was conducted. The synthesized novel graft copolymer may find potential application to be used as metal adsorbents.

Synthesis of chitosan and N-vinylimidazole graft-copolymers and the properties of their aqueous solutions

The aim of this work is to synthesise chitosan and N-vinylimidazole graft-copolymers of various compositions and to study the properties of their aqueous solutions.Chitosan and N-vinylimidazole graft-copolymers were obtained by solution polymerisation in the presence of a ceric ammonium nitrate redox initiator. The synthesised graft copolymers were characterised by FTIR to determine their compositions and the grafted side chains of poly-N-vinylimidazole were characterised by gel permeation chromatography to determine their molecular wights and polydispersity indices. It was established that the obtained products are characterised by high values of yield and grafting efficiency and low values of the polydispersity index. It was found that when the content of the N-vinylimidazole links is above 57 wt%, the synthesised graft copolymers are water-soluble. Aqueous solutions of the obtained copolymers were characterised using dynamic light scattering, transmission electron microscopy, and laserDoppler microelectrophoresis. The study showed that macromolecules of graft copolymers in aqueous solutions have stimuli-sensitive properties with respect to the medium reaction and at a concentration above 10–2 wt% are characterised by a tendency to self-association forming core-crown aggregates, the geometry of which depends on the molecular masses of the grafted chains. Associates of macromolecules in solutions are characterised by positive values of the electrokinetic potential, the values of which also depend on the medium reaction. Thus, it was found that the ceric ammonium nitrate initiator allows obtaining chitosan and N-vinylimidazole graft-copolymers showing stimuli-sensitive properties in aqueous solutions and prone to self-association at concentrations above 10–2 wt%.

Aqueous Phase Bromination by Micellar Solution of Sodium Dodecyl Sulfate (SDS): An Undergraduate Chemistry Experiment

Background: Bromination is a key reaction in chemical industry, since the organobromines find application in diverse fields like pharmaceuticals, dyes, fire retardants and as intermediates in chemical synthesis. Objective: To carry out green, in-situ bromination of acetanilide in aqueous medium using micellar SDS as catalyst. Methods: Bromination of acetanilide in-situ using potassium bromide as a non-corrosive source of bromine, ceric ammonium nitrate as oxidant, micellar solution of sodium dodecyl sulphate (SDS) as catalyst and water as solvent. Results: p-Bromoacetanilide was prepared in excellent yields, at room temperature, using green chemistry principles. Conclusion: The presented method provides a fast and environmentally safe route for the preparation of p-bromoacetanilide from acetanilide. It avoids the use of volatile, corrosive, and hazardous substances like liquid bromine and acetic acid. The use of water makes it safer and free from hazardous organic solvents. This reaction can be suitably adopted at the undergraduate level and may find use in the synthesis of commercially important bromo compounds.

Ceric Ammonium Nitrate supported on Hy-Zeolite Catalyzed Oxidative Condensation Reaction and its Docking Studies

The chemistry of chalcone has been recognized as a significant field of study. Chalcone serve as to prepare starting materials for the synthesis of various heterocyclic compounds. From the backbone of reported literature, we have developed an alternative heterogeneous and simple catalytic system for the synthesis of chalcones via the oxidative condensation of benzyl alcohol with substituted acetophenone using metal nitrate supported HY-Zeolite as a catalyst. 30 mol% CAN supported HY-zeolite has been efficiently used as a catalyst for the oxidative condensation reaction of benzyl alcohol with substituted acetophenones in the presence of hydrogen peroxide as an oxidant in toluene to afford the corresponding chalcones in good to moderate yields. Docking studies were carried out for the synthesized compounds towards the protein Lysine aminotransferase using the software.

Removal of Heavy Metal Ions from Wastewater Using Hydroxyethyl Methacrylate-Modified Cellulose Nanofibers: Kinetic, Equilibrium and Thermodynamic Analysis

The objective of this work was to fabricate modified cellulose nanofibers (CNFs) for the removal of heavy metal ions (Cd2+ and Pb2+) from wastewater. Cellulose was modified with 2-hydroxyethyl methacrylate (HEMA) via grafting copolymerization using the microwave-assisted technique in the presence of ceric ammonium nitrate (CAN) as an initiator. Prepared cellulose-graft-(2-hydroxyethyl methacrylate) (HEMA/C) copolymers were characterized using Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). Different factors affecting the graft yield, such as irradiation time, monomer concentrations, and initiator concentrations, were investigated. Furthermore, cellulose-graft-(2-hydroxyethyl methacrylate) copolymer nanofibers (HEMA/CNF) were fabricated by electrospinning using N,N-dimethylacetamide-LiCl as a solvent. Electrospun nanofiber copolymers were characterized using SEM and thermogravimetric analysis (TGA). Operating parameters, including time, starting metal concentrations, and adsorbent concentration, were analyzed at a pH of 5.6 for the two metal ions. The best-fit model of adsorption energy was the pseudo-second-order model, and adsorption isotherms at equilibrium were well described by the Langmuir and Freundlich models. The negative values of ΔG and positive values of ΔH and ΔS suggest that the adsorption of Cd2+ and Pb2+ ions onto electrospun HEMA/CNF is a spontaneous, endothermic, and favorable reaction.