Research articles authored by NIIST researchers published in 2022 http://localhost:8080/xmlui/handle/123456789/3931 2026-04-13T10:38:05Z 2026-04-13T10:38:05Z Orodepo, GO Bej, S Gowd, E B Ramakrishnan, S http://localhost:8080/xmlui/handle/123456789/4461 2023-04-10T09:56:39Z 2022-07-15T00:00:00Z

Main-Chain Side-Chain Combined Liquid Crystalline Polymers Bearing Azobenzene and Biphenyl-Based Mesogens - Segregation of the Mesogens within Two Distinct Layers Orodepo, GO; Bej, S; Gowd, E B; Ramakrishnan, S Two different mesogenic units, namely biphenyl and azobenzene, were installed centrally within the polymer backbone and pendant alkylene segments; the purpose was to examine if chain folding of the backbone occurs so as to segregate the azobenzene and biphenyl units in adjacent layers of a smectic-type ordering. Two sets of isomeric main-chain side-chain liquid crystalline polymers (MCSC-LCPs), namely SC-AzoCx-MC-BPCx and SC-BPCx-MC-AzoCx (x=6 or 10), were synthesised; the former series has biphenyl in the backbone and azobenzene in the side-chain, while their locations are switched in the latter. It was observed that all four polymers were semicrystalline at room temperature and exhibited a smectic mesophase upon melting. DSC and X-ray scattering studies revealed that switching the locations of the azobenzene and biphenyls had little effect on; the phase transition temperatures and smectic layer spacings. A second series, namely SC-AzoCx-MC-BPCy and SC-BPCx-MC-AzoCy, where the length of alkylene spacers in the side-chain (Cx) and backbone (Cy) is different, was also studied; this was done to examine the influence of unequal alkylene segment lengths on the mesophase structure and interlayer spacing, and importantly, whether the zigzag folding-induced formation of a layered structure is retained, despite their unsymmetrical nature.

2022-07-15T00:00:00Z Sherpa, K C Kundu, D Banerjee, S Ghangrekar, M M Banerjee, R http://localhost:8080/xmlui/handle/123456789/4453 2023-04-10T09:25:39Z 2022-06-01T00:00:00Z

An Integrated Biorefinery Approach for Bioethanol Production from Sugarcane Tops (Preprint) Sherpa, K C; Kundu, D; Banerjee, S; Ghangrekar, M M; Banerjee, R Bioethanol from lignocellulosic biomass is a promising alternative to petroleum-based fuels to alleviate greenhouse gas emissions and reduce the dependency on fossil fuels. The lignocellulosic biomass is exploited for ethanol production due to its sustainability and abundance. Sugarcane tops, an agricultural residue, was employed in the present investigation to assess its potential as a feedstock for bioethanol production by adopting different fermentation approaches, namely separate fermentation, simultaneous saccharification and fermentation (SSF) and partially consolidated bioprocessing (PCBP). The present study demonstrated the potential of mono and co-fermentation for ethanol production. Comparison between separate fermentation and SSF using S.cerevisiae showed the latter to be more efficient with ethanol production of 5.69 % (v/v) in 30.67 h of fermentation time than separate fermentation with 3.76 % (v/v) ethanol in 48 h. An integrated fermentation strategy stated as partially consolidated bioprocessing (PCBP) was investigated to improve fermentation efficiency. This process integrates simultaneous pretreatment and saccharification (SPS), conducted by enzyme blends of laccase and cellulase followed by co-fermentation using S. cerevisiae and xylose-fermenting yeast AKBR 212. This approach resulted in a 7.57 % (v/v) maximum ethanol concentration in 24.30 h. The different fermentation strategies involved enzymes and yeasts only, thus offering a green biotechnology approach towards converting sugarcane tops into bioethanol.

2022-06-01T00:00:00Z Akhila, A K Anjali, Chithrambattu Balaraman, Vedhanarayanan Suresh Babu, A R Vakayil K, Praveen Renuka, N K http://localhost:8080/xmlui/handle/123456789/4440 2023-04-06T13:16:46Z 2022-01-01T00:00:00Z

Fluoride-philic Reduced Graphene Oxide-fluorophore Anion Sensors (Preprint) Akhila, A K; Anjali, Chithrambattu; Balaraman, Vedhanarayanan; Suresh Babu, A R; Vakayil K, Praveen; Renuka, N K The detection and quantification of the fluoride ion, one of the most significant anions, have attracted much research interest because of its striking role in oral/bone health and clinical treatment of osteoporosis. A set of F− ion sensors have been reported here, which operate through the fluorescence turn-on response of reduced graphene oxide (rGO)–fluorophore noncovalent conjugate. The developed sensing systems perform well at neutral pH in aqueous solutions, and the response towards F− ions was initiated within seconds. The high specificity for these optical sensors towards F− ions, among a set of significant competing anions, was notable. For the three fluorescent organic dyes selected for study, tetraphenylporphyrin (DTPP), curcumin (DCURN), and coumarin (DCMN), the low-level detection (LOD) ability increased with an increase in π-interactions between rGO and the fluorophore. A fall in LOD to the attomolar level could be achieved for the rGO-DTPP system. The turn-on fluorescence strategy was extended further to develop solid-state sensor strips for F− ion detection at the attomolar level. The fluoride-philic nature of rGO–fluorophore systems was traced by systematic investigations using FT-IR, XRD, and XPS techniques, which revealed that the interaction between the most electronegative F− ion and the rGO in the sensor unit leads to the formation of the stable compound graphite fluoride, and this conversion in turn switches on the quenched fluorescence of the fluorophore.

2022-01-01T00:00:00Z Rahul, P Veena, S John, Jubi http://localhost:8080/xmlui/handle/123456789/4276 2023-03-10T08:11:41Z 2022-09-30T00:00:00Z

Inverse Electron Demand Diels Alder Reaction of Aza-o-Quinone Methides and Enaminones: Accessing 3-Aroyl Quinolines and Indeno[1,2-b]quinolinones Rahul, P; Veena, S; John, Jubi We have developed a Diels Alder cycloaddition route toward 3-aroyl quinolines from enaminones and in situ generated aza-o-quinone methides. The reaction was found to be general with a range of substituted enaminones and aza-o-quinone methides, and we could validate the applicability of the methodology in gram scale. We also demonstrated a one-pot strategy toward 3-acyl quinolines starting from the corresponding aliphatic ketones. Finally, we utilized the 3-aroyl quinolines for synthesizing indeno[1,2-b]quinolinones via a Pd-catalyzed dual C–H activation approach.

2022-09-30T00:00:00Z