http://nopr.niscpr.res.in/handle/123456789/58672 2026-10-10T07:53:18Z http://nopr.niscpr.res.in/handle/123456789/58699 Title: Heterogeneous polymer supported and soluble tantalum metal complex catalysts for acylation reaction: A kinetic study Authors: Murugan, E; Arunachalam, P; Jebaranjitham, J Nimita; Santhoshkumar, S; Saravanakumar, A Abstract: New soluble and insoluble Tantalum pentachloride complex catalysts are prepared by simple procedures using pyridine and polymer-supported cross-linked (poly-4-vinyl pyridine) beads (PSCPVP) respectively as supports and Tantalum pentachloride as a catalytic moiety (TaCl5). The prepared soluble Py-TaCl5 and insoluble bead-shaped PSCPVP-TaCl5 catalysts have been characterized with FT-IR, UV-Vis, SEM, TGA and elemental analysis techniques. The catalytic efficiency of these catalysts has been examined through acylation of ethanol as a model reaction under identical pseudo first order reaction condition. From the calculated kobs values, it has been noticed that both the catalysts are active and however, Py-TaCl5shown 1.65 fold has increased activity (kobs =11.42x103 min-1) than insoluble PSCPVP-TaCl5 catalyst (kobs= 6.98x103, min-1). Although, PSCPVP-TaCl5 has shown lesser activity than soluble due to its lower cost, recyclability and reusable nature up to third cycle, it has received greater recognition. Hence, in order to utilize this insoluble bead-shaped PSCPVP-TaCl5 catalyst to pack in column reactor and to carry out the same reaction for continuous mode operation at industrial level, detailed kinetics study for acylation of ethanol has been conducted under pseudo first order condition by varying the different experimental parameters and has observed that each parameter has influenced the reaction. The obtained kobs value reveals that reaction rates increase with the increase in the stirring speed, [substrate], [catalyst] and temperature. The thermodynamic parameters viz., activation energy (Ea), entropy (∆S), enthalpy (∆H) and free energy (∆G#) for the reaction are also calculated for the first time and their observed values are 35.2 kJmol-1, -64.6 kJ-1mol-1, 37.7 kJmol-1and 57.3 kJmol-1 respectively. The prepared insoluble catalyst is stable even after its use for three times in acylation without losing its efficiency, thus it is better suited for industrial applications. Page(s): 495-505 2021-09-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/58698 Title: Application of polymer-bound Cu(II) complex of 2-phenylbenzimidazole towards oxidative bromination and oxidative esterification of organic substrates Authors: E R, Shilpa; V, Gayathri Abstract: Application of polymer immobilized Cu(II)(PS-Cu(II)PBMZL) complex of 2-phenylbenzimidazole in oxidative bromination and oxidative esterification of organic compounds is reported. The complex has been characterized by CHNS analysis, UV-Vis/DRS, FT-IR, ESR spectroscopic studies, magnetic moment measurements and TG analysis. A shift in νC=N in the polymer-bound complex compared with the ligand indicates its complexation to Cu(II) center. A distorted octahedral coordination of Cu(II) in PS-Cu(II)PBMZL is confirmed by the electronic spectral data and the efficient binding of PBMZL is ascertained by adecrease in the intensity of νCH2Cl peak in the PS-PBMZL compared to the polymer support. An array of experiments has been carried out to assess the influence of various reaction parameters on the performance of PS-Cu(II)PBMZL. The activity of the polymer-bound complex is higher than the unbound complex. In the case of oxidative bromination, PS-Cu(II)PBMZLH displayed a 65% phenol conversion with 61% 2-bromophenol selectivity. The % benzaldehyde conversion and methyl benzoate selectivity in the case of oxidative esterification has been found to be 79 and 82%. Compiling all these results along with the knowledge obtained regarding the most probable reactive species, tentative mechanisms have been proposed. Page(s): 506-517 2021-09-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/58697 Title: PANI blended MoS₂ decorated GO ternary nanocomposite for efficient electrochemical sensing of crucial components in food and beverages. Authors: Murugan, E; Dhamodharan, A; Saranya, S Abstract: An electrochemical detection dependent on Polyaniline (PANI) blended MoS2 decorated GO (MoS2/PANI@GO) ternary nanocomposite has been developed and used for selective and concomitant determination of Vanillin (VAN), Theophylline (TP) and Caffeine (CAF). The surface morphology and structural properties of the composite are denoted by various scientific methods. The electrochemical behaviour of MoS2/PANI@GO has been investigated by Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV). The electrochemical oxidation (anodic) peaks have been observed at 0.59, 1.1 and 1.36v in phosphate buffer (pH 7) for Vanillin, Theophylline and Caffeine, respectively. A good linear current response and limit of detection of 0.043, 0.062 and 0.07 of VAN, TP and CAF, are obtained respectively. The concocted electrode reveals low detection limit, wide linear range, excellent reproducibility, high acuteness and stability. The study is also continued to the analysis of the certain components in the commercial foods and beverage samples. Page(s): 518-527 2021-09-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/58696 Title: Electrochemical determination of caffeine in beverage using graphene oxide modified glassy carbon electrode Authors: Murugan, E; Poongan, A Abstract: Graphene oxide (GO) has been synthesized through simple experimental method and used for surface modification of glassy carbon electrode, thus developed a new efficient GO/GCE as a sensor for identification and quantification of Caffeine in beverage samples. Common analytical techniques have been employed to establish the physiochemical properties of graphene oxide. The electro catalytic activity GO/GCE has been examined towards sensing and quantification of caffeine through Cyclic voltammetry and Differential pulse voltammetry. The results show high sensitivity with a wide linear range in concentration 3.2-183 µM and low detection limit (LOD) 0.043 µM. In addition, in order to inspect the real time application of GO/GCE, it has been also employed to determine the concentration of caffeine in cola, Red bull and coffee samples.Very low LOD has been observed for caffeine even in real sample analysis and hence this electrode can very well be expended for real time application and thus enable to maintain the quality control of the food samples. Page(s): 528-536 2021-09-01T00:00:00Z