@article { ISI:000331904500008, title = {Synthesis and reactivity of magnetically diverse Au@ Ni core-shell nanostructures}, journal = {Particle \& Particle Systems Characterization}, volume = {31}, number = {2}, year = {2014}, month = {FEB}, pages = {236-244}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

Core-shell bimetallic Au@Ni nanoparticles, with gold cores and thin nickel shells with overall size less than 10 nm, are synthesized and stabilized in pure cubic (fcc) and hexagonal (hcp) phase. Due to their unique crystal, electronic, and geometric structure, they show interesting magnetic and chemical properties. The Au@Ni-fcc is magnetic, whereas Au@Ni-hcp is non-magnetic. Both the bimetallic nanostructures are stable to surface oxidation until 150 degrees C and show excellent catalytic activity for p-nitrophenol reduction reaction.

}, keywords = {Au-Ni nanoparticles, bimetallic nanostructures, magnetic core-shell nanoparticles, oxidation resistance}, issn = {0934-0866}, doi = {10.1002/ppsc.201300195}, author = {Bharathan, Vysakh A. and Raj, Govind K. and Joy, Pattayil Alias and Vinod, Chathakudath P.} } @article { ISI:000352488300022, title = {Activity enhancement upon the incorporation of titanium: au@ti-sio2 core-shell nanocatalysts for the CO oxidation reaction}, journal = {ChemCatChem}, volume = {7}, number = {7}, year = {2015}, month = {APR}, pages = {1222-1230}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

The encapsulation of gold nanoparticles 8-12nm in size within a porous Ti-SiO2 shell to form a core-shell nanoarchitecture was investigated, and the catalytic activity of the resulting structure was probed. Detailed characterization of the synthesized materials shows that the core-shell morphology is lost beyond a certain amount of incorporated titanium, and results in normal gold-supported Ti-SiO2. The material has a high surface area (913m(2)g(-1)) and high porosity, both of which make it an excellent choice for catalytic applications. With the optimum amount of incorporated Ti, the core-shell catalyst shows excellent room-temperature CO oxidation activity over several cycles with retention of its morphology at higher temperatures.

}, keywords = {core-shell structures, gold nanoparticles, Oxidation, Ti-SiO2}, issn = {1867-3880}, doi = {10.1002/cctc.201402954}, author = {Sekhar, Anandakumari C. Sunil and Kottavarithottil Ziyad and Soni, Yogita and Vinod, Chathakudath P.} } @article {45882, title = {Pd loaded amphiphilic COF as catalyst for multi-fold Heck reactions, C-C couplings and CO oxidation}, journal = {Scientific Reports}, volume = {5}, year = {2015}, month = {JUN }, pages = {10876}, type = {Article}, abstract = {

COFs represent a class of polymers with designable crystalline structures capable of interacting with active metal nanoparticles to form excellent heterogeneous catalysts. Many valuable ligands/monomers employed in making coordination/organic polymers are prepared via Heck and C-C couplings. Here, we report an amphiphilic triazine COF and the facile single-step loading of Pd-0 nanoparticles into it. An 18-20\% nano-Pd loading gives highly active composite working in open air at low concentrations (Conc. Pd(0) \< 0.05 mol\%, average TON 1500) catalyzing simultaneous multiple site Heck couplings and C-C couplings using {\textquoteleft}non-boronic acid{\textquoteright} substrates, and exhibits good recyclability with no sign of catalyst leaching. As an oxidation catalyst, it shows 100\% conversion of CO to CO2 at 150 degrees C with no loss of activity with time and between cycles. Both vapor sorptions and contact angle measurements confirm the amphiphilic character of the COF. DFT-TB studies showed the presence of Pd-triazine and Pd-Schiff bond interactions as being favorable.

}, issn = {2045-2322}, doi = {10.1038/srep10876}, author = {Mullangi, Dinesh and Nandi, Shyamapada and Shalini, Sorout and Sreedhala, Sheshadri and Vinod, Chathakudath P. and Vaidhyanathan, Ramanathan} } @article {45637, title = {Highly stable In-SBA-15 catalyst for vapor phase Beckmann rearrangement reaction}, journal = {Microporous and Mesoporous Materials}, volume = {234}, year = {2016}, month = {NOV }, pages = {293-302}, type = {Article}, abstract = {

The Indium doped SBA-15 material was prepared by sol-gel method and tested for vapor phase Beckman rearrangement reaction. Among three indium loading, In/Si ratio of 2/100 was found as an optimum composition in terms of caprolactam selectivity (100\%) and cyclohexanone oxime conversion (100\%). The catalysts were characterized by N-2 adsorption, small-angle X-rays/neutron scattering (SAXS/SANS), XRD, FESEM, HRTEM, EDX, UV, FTIR and NH3-TPD techniques. In-situ SANS experiment was performed on the adsorption of CO2 to detect the micropores in the mesopore wall. All catalysts samples have highly ordered hexagonal structure with well dispersed indium in the silica matrix. The fine tuning of weak and strong acid sites were found in indium doped SBA-15 (In/Si = 2/100) catalyst. The same catalyst showed optimum catalytic performance, high space time yield 114.4 mol/h/g(cat) and high stability till 6 h of reaction without deactivation. The micro-kinetic analysis showed that there were no external and internal diffusion limitations in the SBA-15 catalyst. The reaction mechanism of Beckmann rearrangement over In-SBA-15 has been elucidated. (C) 2016 Elsevier Inc. All rights reserved.

}, keywords = {e-Caprolactam, In-situ SANS, indium, SAXS, SBA-15}, issn = {1387-1811}, doi = {10.1016/j.micromeso.2016.07.024}, author = {Kumar, Rawesh and Shah, Sneha and Bahadur, Jitendra and Melnichenko, Yuri B. and Sen, Debasis and Mazumder, S. and Vinod, Chathakudath P. and Chowdhury, Biswajit} } @article {45630, title = {Low band gap benzimidazole COF supported Ni3N as highly active OER catalyst}, journal = {Advanced Energy Materials}, volume = {6}, year = {2016}, month = {DEC }, pages = {Article No:1601189}, abstract = {

Covalent organic frameworks (COFs) have structures and morphologies closely resembling graphenes, whose modular construction permits atomiclevel manipulations. This, combined with their porous structure, makes them excellent catalyst supports. Here, the high electrocatalytic activity of a composite, formed by supporting Ni3N nanoparticles on a benzimidazole COF, for oxygen evolution reaction is shown. The composite oxidizes alkaline water with a near-record low overpotential of 230 mV @ 10 mA cm(-2) (eta(10)). This high activity is attributed to the ability of the COF to confine the Ni3N nanoparticles to size regimes otherwise difficult to obtain and to its low band gap character (1.49 eV) arising from the synergy between the conducting Ni3N nanoparticles and the pi-conjugated COF. The COF itself, as a metalfree self-standing framework, has an oxygen evolution reaction activity with 10 of 400 mV. The periodic structure of the COF makes it serve as a matrix to disperse the catalytically active Ni3N nanoparticles favoring their high accessibility and thereby good charge-transport within the composite. This is evident from the amount of O-2 evolved (230 mmol h(-1) g(-1)), which, to the best of our knowledge, is the highest reported. The work reveals the emergence of COF as supports for electrocatalysts.

}, issn = {1614-6832}, doi = {10.1002/aenm.201601189}, author = {Nandi, Shyamapada and Singh, Santosh Kumar and Mullangi, Dinesh and Illathvalappil, Rajith and George, Leena and Vinod, Chathakudath P. and Kurungot, Sreekumar and Vaidhyanathan, Ramanathan} } @article { ISI:000372425600066, title = {Simple, phosphine free, reusable Pd(II)-2,2 {\textquoteleft}-dihydroxybenzophenone-SBA-15 catalyst for arylation and hydrogenation reactions of alkenes}, journal = {New Journal of Chemistry}, volume = {40}, number = {3}, year = {2016}, month = {JAN}, pages = {2423-2432}, publisher = {ROYAL SOC CHEMISTRY}, type = {Article}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

An efficient, simple, phosphine and co-catalyst free C-C coupling reaction heterogeneous catalyst via a post grafting method is developed and reported. A covalently anchored phosphine free Pd(II) based 2,2{\textquoteright}-dihydroxybenzophenone (DHBP) complex over organofunctionalized SBA-15 has been synthesized by the reaction between aminofunctionalized SBA-15 (NH(2)SBA-15) and a 2,2{\textquoteright}-dihydroxybenzophenone (DHBP) ligand, and further complexation with Pd(II)Cl-2 to get Pd(II)-DHBP@ SBA-15. The synthesized catalysts were characterized by elemental analysis, XRD, N-2 sorption analyses, TG, DTA, FT-IR, solid state C-13 and Si-29 NMR spectra, XPS, UV-Visible, SEM, EDAX and TEM. The synthesized catalysts were screened in arylation (Heck reactions) and hydrogenation reactions of alkenes, and the results show that Pd(II)-DHBP@ SBA-15 exhibits high conversion and selectivity towards arylation and hydrogenation reactions of alkenes with high stability. The anchored solid catalysts can be recycled effectively and reused several times without major loss in activity.

}, issn = {1144-0546}, doi = {10.1039/c5nj02686e}, author = {Lazar, Anish and Vinod, Chathakudath P. and Singh, Anand Pal} } @article {45830, title = {Synthesis of Au@Ni bimetallic core shell nanoparticle and nanochains in soyabean oil and their catalytic hydrogenation reactions}, journal = {ChemistrySelect}, volume = {1}, year = {2016}, month = {FEB}, pages = {140-146}, type = {Article}, abstract = {

Synthesis of Au@Ni bimetallic core shell nanostructures using commercially available soya bean oil as the solvent through a sequential reduction strategy is reported. The energy efficiency and economic viability comes from the much milder temperatures and replacement of expensive and environmentally hazardous solvents like long chain organic amines and acids previously reported for synthesis. Thus, core shell nanoparticles having size regime of 10-15 nm with an excellent control over the nickel shell thickness (2 nm) over the gold core (8-10 nm) and Au@Ni nanochains is achieved. The synthesized materials are demonstrated to synergistically catalyze hydrogenation of nitro and C-C multiple bonds with much better efficiency as compared to individual nanoparticle counterparts.

}, keywords = {Bimetallic nanoparticles, Gold catalysis, hydrogenation reactions, synergistic effects}, issn = {2365-6549}, doi = {10.1002/slct.201500006}, author = {Bharathan, Vysakh A. and Yadukiran, V. and Lazar, Anish and Singh, Anand. P. and Vinod, Chathakudath P.} } @article {45385, title = {Highly stable COF-supported Co/Co(OH)(2) nanoparticles heterogeneous catalyst for reduction of nitrile/nitro compounds under mild conditions}, journal = {Small}, volume = {14}, year = {2018}, month = {SEP}, type = {Article}, abstract = {Ordered nanoporosity in covalent organic framework (COF) offers excellent opportunity for property development. Loading nanoparticles (nPs) onto them is one approach to introducing tailor-made properties into a COF. Here, a COF-Co/Co(OH)(2) composite containing about 16 wt\% of <6 nm sized Co/Co(OH)(2) nPs is prepared on a N-rich COF support that catalyzes the release of theoretical equivalence of H-2 from readily available, safe, and cheap NaBH4. Furthermore, the released H-2 is utilized for the hydrogenation of nitrile and nitro compounds to amines under ambient conditions in a facile one-pot reaction. The COF "by choice" is built from "methoxy" functionalized dialdehydes which is crucial in enabling the complete retention of the COF structure under the conditions of the catalysis, where the regular Schiff bonds would have hydrolyzed. The N-rich binding pockets in the COF ensure strong nP-COF interactions, which provides stability and enables catalyst recycling. Modeling studies reveal the crucial role played by the COF in exposing the active facets and thereby in controlling the activation of the reducing agent. Additionally, via density functional theory, we provide a rational explanation for how these COFs can stabilize nanoparticles which grow beyond the limiting pore size of the COF and yet result in a truly stable heterogeneous catalyst - a ubiquitous observation. The study underscores the versatility of COF as a heterogeneous support for developing cheap and highly active nonnoble metal catalysts.}, doi = {10.1002/smll.201801233}, author = {Mullangi, Dinesh and Chakraborty, Debanjan and Pradeep, Anu and Koshti, Vijay and Vinod, Chathakudath P. and Panja, Soumendranath and Nair, Sunil and Vaidhyanathan, Ramanathan} } @article {44522, title = {Mesoporous shell@macroporous core aluminosilicates as sustainable nanocatalysts for direct N-alkylation of amines}, journal = {Chemnanomat}, volume = {4}, year = {2018}, month = {JUN}, pages = {537-541}, abstract = {

Aluminosilicate spheres with a macroporous core and mesoporous shell (Si/Al ratio of 11) is synthesised by a sol-gel method utilizing cetyltrimethyl ammonium bromide (CTAB) as a structure directing agent in basic medium. The selective incorporation of aluminium in the silica matrix results in the formation of aluminosilicates with an overall acidity of 0.32mmol/g with interconnected pores. Direct N-alkylation reaction is a prototype of C-N bond formation reaction and meso- macroporous aluminosilicate is shown to catalyze this reaction with excellent yield. The catalyst is tested and found sustainable for five catalytic cycles even without any high temperature regeneration step.

}, keywords = {Aluminosilicates, macroporous, Mesoporous, N-alkylation, nanocatalysis}, issn = {2199-692X}, doi = {10.1002/cnma.201800081}, author = {Sekhar, Anandakumari C. Sunil and Ashokkumar, Anumol Erumpukuthickal and Cygnet, Choorapoikayil T. and Lakshmi, Saseendranpillai Vidhya and Deepak, Francis Leonard and Vinod, Chathakudath P.} } @article {44639, title = {Selective oxidation of cyclohexane to cyclohexanone using chromium oxide supported mesoporous MCM-41 nanospheres: probing the nature of catalytically active chromium sites}, journal = {ChemCatChem}, volume = {10}, year = {2018}, month = {AUG}, pages = {3291-3298}, abstract = {

Highly dispersed chromium oxide supported mesoporous MCM-41 nanosphere catalysts have been synthesized using a simple wet impregnation method. This work is devoted to a systematic study to reveal the active Cr sites in chromium oxide supported MCM-41 nanosphere catalysts for the selective oxidation of cyclohexane to cyclohexanone. To probe the nature of the active species, we synthesized 0.5-10wt\% Cr loaded catalysts and characterized them by using XRD, UV/Vis spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, extended X-ray absorption fine structure analysis, X-ray absorption near edge structure analysis, N-2 sorption analysis, FTIR spectroscopy, (SiNMR)-Si-29 spectroscopy, SEM, and TEM. The liquid-phase oxidation of cyclohexane to cyclohexanone (99\% selectivity) was performed under mild reaction conditions, and the results reveal clearly that the 5wt\% Cr loaded catalyst was optimum for the reaction. The initial composition of isolated Cr3+ species in the catalyst is the major factor that influences the enhanced activity for cyclohexane oxidation.

}, keywords = {chromium, heterogeneous catalysis, Nanostructures, Oxidation, supported catalysts}, issn = {1867-3880}, doi = {10.1002/cctc.201800309}, author = {Betsy, Kurisingal J. and Nayak, Chandrani and Lazar, Anish and Krishnan, Athira and Bhattacharyya, Dibyendu and Jha, Shambhu N. and Vinod, Chathakudath P.} } @article {46294, title = {Carbon derived from soft pyrolysis of a covalent organic framework as a support for small-sized RuO2 showing exceptionally low overpotential for oxygen evolution reaction}, journal = {ACS Omega}, volume = {4}, year = {2019}, month = {AUG}, pages = {13465-13473}, type = {Article}, abstract = {

Electrochemical water splitting is the most energy-efficient technique for producing hydrogen and oxygen, the two valuable gases. However, it is limited by the slow kinetics of the anodic oxygen evolution reaction (OER), which can be improved using catalysts. Covalent organic framework (COF)-derived porous carbon can serve as an excellent catalyst support. Here, we report high electrocatalytic activity of two composites, formed by supporting RuO2 on carbon derived from two COFs with closely related structures. These composites catalyze oxygen evolution from alkaline media with overpotentials as low as 210 and 217 mV at 10 mA/cm(2), respectively. The Tafel slopes of these catalysts (65 and 67 mV/dec) indicate fast kinetics compared to commercial RuO2. The observed activity is the highest among all RuO2-based heterogeneous OER catalysts-a touted benchmark OER catalyst. The high catalytic activity arises from the extremely small-sized (similar to 3-4 nm) RuO2 nanoparticles homogeneously dispersed in a micro-mesoporous (BET = 517 m(2)/g) COF-derived carbon. The porous graphenic carbon favors mass transfer, while its N-rich framework anchors the catalytic nanoparticles, making it highly stable and recyclable. Crucially, the soft pyrolysis of the COF enables the formation of porous carbon and simultaneous growth of small RuO2 particles without aggregation.

}, issn = {2470-1343}, doi = {10.1021/acsomega.9b01777}, author = {Chakraborty, Debanjan and Nandi, Shyamapada and Illathvalappil, Rajith and Mullangi, Dinesh and Maity, Rahul and Singh, Santosh K. and Haldar, Sattwick and Vinod, Chathakudath P. and Kurungot, Sreekumar and Vaidhyanathan, Ramanathan} } @article {46117, title = {Cu/Cu2O nanoparticles supported on a phenol-pyridyl COF as a heterogeneous catalyst for the synthesis of unsymmetrical diynes via glaser-hay coupling}, journal = {ACS Applied Materials \& Interfaces}, volume = {11}, year = {2019}, month = {MAY }, pages = {15670-15679}, type = {Article}, abstract = {

Covalent organic frameworks (COFs) are a new class of porous crystalline polymers with a modular construct that favors fiinctionalization. COF pores can be used to grow nanoparticles (nPs) with dramatic size reduction, stabilize them as dispersions, and provide excellent nP access. Embedding substrate binding sites in COFs can generate host-guest synergy, leading to enhanced catalytic activity. In this report, Cu/Cu2O nPs (2-3 nm) are grown on a COF, which is built by linking a phenolic trialdehyde and a triamine through Schiff bonds. Their micropores restrict the nP to exceptionally small sizes (similar to 2-3 nm), and the pore walls decorated with strategically positioned hydrogen-bonding phenolic groups anchor the substrates via hydrogen-bonding, whereas the basic pyridyl sites serve as cationic species to stabilize the [CuclusterCl2](2-) type reactive intermediates. This composite catalyst shows high activity for Glaser-Hay heterocoupling reactions, an essential 1,3-diyne yielding reaction with widespread applicability in organic synthesis and material science. Despite their broad successes in homocoupled products, preparation of unsymmetrical 1,3-diynes is challenging due to poor selectivity. Here, our COF-based Cu catalyst shows elevated selectivity toward heterocoupling product(s) (Cu nP loading 0.0992 mol \%; turn over frequency: similar to 4S-50; turn over number: similar to 17S-190). The reversible redox activity at the Cu centers has been demonstrated by carrying out X-ray photoelectron spectroscopy on the frozen reactions, whereas the crucial interactions between the substrates and the binding sites in their optimized configurations have been modeled using density functional theory methods. This report emphasizes the utility of COFs in developing a heterogeneous catalyst for a truly challenging organic heterocoupling reaction.

}, keywords = {Copper nanoparticles, Covalent organic framework, Glaser-Hay heterocoupling, heterogeneous catalysis, unsymmetrical diynes}, issn = {1944-8244}, doi = {10.1021/acsami.9b02860}, author = {Chakraborty, Debanjan and Nandi, Shyamapada and Mullangi, Dinesh and Haldar, Sattwick and Vinod, Chathakudath P. and Vaidhyanathan, Ramanathan} } @article {46278, title = {MnO2@Fe3O4 Magnetic Nanoparticles as Efficient and Recyclable Heterogeneous Catalyst for Benzylic sp(3) C-H Oxidation}, journal = {Chemistry-An Asian Journal}, year = {2019}, month = {SEP}, type = {Article}, abstract = {

Herein, we report a highly chemoselective and efficient heterogeneous MnO2@Fe3O4 MNP catalyst for the oxidation of benzylic sp(3) C-H group of ethers using TBHP as a green oxidant to afford ester derivatives in high yield under batch/continuous flow module. This catalyst was also effective for the benzylic sp(3) C-H group of methylene derivatives to furnish the ketone in high yield which can be easily integrated into continuous flow condition for scale up. The catalyst is fully characterized by spectroscopic techniques and it was found that 0.424 \% MnO2@Fe3O4 catalyzes the reaction; the magnetic nanoparticles of this catalyst could be easily recovered from the reaction mixture. The recovered catalyst was recycled for twelve cycles without any loss of the catalytic activity. The advantages of MnO2@Fe3O4 MNP are its catalytic activity, easy preparation, recovery, and recyclability, gram scale synthesis with a TOF of up to 14.93 h(-1) and low metal leaching during the reaction.

}, doi = {10.1002/asia.201900810}, author = {Pandey, Akanksha M. and Agalave, Sandip G. and Vinod, Chathakudath P. and Gnanaprakasam, Boopathy} } @article {47319, title = {Boron nitride and oxide supported on dendritic fibrous nanosilica for catalytic oxidative dehydrogenation of propane}, journal = {ACS Sustainable Chemistry \& Engineering}, volume = {8}, year = {2020}, month = {NOV }, pages = {16124-16135}, type = {Article}, abstract = {

In this work, we were able to significantly increase the activity of boron nitride (BN) catalysts used for the oxidative dehydrogenation (ODH) of propane by designing and synthesizing BN supported on dendritic fibrous nanosilica (DFNS). DFNS/BN showed a markedly increased catalytic efficiency, accompanied by exceptional stability and selectivity. Textural characterization, together with solid-state nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopic analyses, indicates the presence of a combination of unique fibrous morphology of DFNS and various boron sites connected to silica to be the reason for this increase in the catalytic performance. Notably, DFNS/B2O3 also showed catalytic activity, although with more moderate selectivity compared to that of DFNS/BN. Solid-state NMR spectra indicate that the higher selectivity of DFNS/BN might stem from a larger amount of hydrogen-bonded hydroxyl groups attached to B atoms. This study indicates that both boron nitride and oxide are active catalysts and by using high surface area support (DFNS), conversion from propane to propene as well as productivity of olefins was significantly increased.

}, keywords = {Electron microscopy, heterogeneous catalysis, Nanostructures, NMR spectroscopy, propane dehydrogenation, X-ray diffraction, X-ray photoelectron spectroscopy}, issn = {2168-0485}, doi = {10.1021/acssuschemeng.0c04148}, author = {Belgamwar, Rajesh and Rankin, Andrew G. M. and Maity, Ayan and Mishra, Amit Kumar and Gomez, Jennifer S. and Trebosc, Julien and Vinod, Chathakudath P. and Lafon, Olivier and Polshettiwar, Vivek} } @article {47318, title = {Nanoporous covalent organic framework embedded with Fe/Fe3O4 nanoparticles as air-stable low-density nanomagnets}, journal = {ACS Applied Nano Materials}, volume = {3}, year = {2020}, month = {SEP }, pages = {9088-9096}, type = {Article}, abstract = {

Covalent organic frameworks (COFs) made of light atoms such as H, C, N, and O with a significant void-to-framework ratio are excellent low-density supports for nanoparticles (nPs). Their framework can be precoded with heteroatoms to ensure binding with metallic nanoclusters. With these advantages, if controlled amounts of magnetic nPs are anchored to them, they can yield low-density organic-inorganic nanomagnets. Their organic nature facilitates fusion with bulk materials such as paper/textile to enable bulk composites with well-dispersed low-density magnets, which have potential for defense and next-generation aviation applications. Herein, we have grown small Fe/Fe3O4 nPs (5-18 wt \%) inside a COF. Interestingly, 300 mg of this organic-inorganic framework material (containing 50 mg of nPs) can lift a vial of similar to 15,000 mg (300 times heavier). Also, the hydrophobic COF wraps around the Fe/Fe3O4 nanocluster retaining its room-temperature magnetic character even after 1 year, while the naked nPs lose it within a few days because of air oxidation. Bulk composites with paper and polymers have been made using this low-density Fe-COF to demonstrate their processability.

}, keywords = {air-stable nanomagnets, Covalent organic framework, Fe/Fe3O4 nanoparticles, low-density nanomagnets, magnetic rayon, nanoporous COF}, issn = {2574-0970}, doi = {10.1021/acsanm.0c01762}, author = {Kushwaha, Rinku and Kaleeswaran, Dhananjayan and Haldar, Sattwick and Chakraborty, Debanjan and Mullangi, Dinesh and Borah, Aditya and Vinod, Chathakudath P. and Murugavel, Ramaswamy and Vaidhyanathan, Ramanathan} } @article {47084, title = {Can we identify the salt-cocrystal continuum state using XPS?}, journal = {Crystal Growth \& Design}, volume = {21}, year = {2021}, month = {FEB }, pages = {735-747}, type = {Article}, abstract = {

X-ray photoelectron spectroscopy (XPS) is used to understand the nature of acid-base crystalline solids, to know whether the product is a salt (proton transfer, O-center dot center dot center dot H-N+) or a cocrystal (neutral adduct, O-H center dot center dot center dot N). The present study was carried out to explore if intermediate states of proton transfer from COOH to nitrogen (the proton resides between hydrogen bonded to O and N, O center dot center dot center dot H center dot center dot center dot N, quasi state) can be differentiated from a salt (complete proton transfer, N+-H center dot center dot center dot center dot O-) and cocrystal (no proton transfer, O-H center dot center dot center dot N) using N 1s XPS spectroscopy. The intermediate states of proton transfer arise when the pK(a) difference between the acid and the conjugate base is between -1 and 4, -1 \< Delta pK(a) \< 4, a situation common with COOH and pyridine functional groups present in drug molecules and pharmaceutically acceptable coformers. Complexes of pyridine N bases with aromatic COOH molecules in nine salts/cocrystals were cocrystallized, and their N 1s core binding energies in XPS spectra were measured. The proton state was analyzed by single-crystal X-ray diffraction for confirmation. Three new complexes were crystallized and analyzed by XPS spectra (without knowledge of their X-ray structures), to assess the predictive ability of XPS spectra in differentiating salt-cocrystal intermediate states against the extremities. The XPS results were subsequently confirmed by single-crystal X-ray data. Complexes of 3,5-dinitrobenzoic acid and isonicotinamide in 1:1 and 1:2 ratios exist as a salt and a salt-cocrystal continuum, respectively, as shown by the N 1s core binding energies. The proton states of the crystalline solids by XPS are in good agreement with the corresponding crystal structures. Other complexes, such as those of 3,5-dinitrobenzoic acid with 1,2-bis(4-pyridyl)ethylene, exhibit a salt-cocrystal continuum, maleic acids with 1,2-bis(4-pyridyl)ethylene and acridine are salts, 2-hydroxybenzoic acid and acridine is a salt, and the complex of 3,5-dinitrobenzoic acid and 3-hydroxypyridine is a salt and salt-cocrystal continuum, while fumaric acids with 1,2-bis(4-pyridyl)ethylene and acridine are cocrystals. Furthermore, three new acidbase complexes of 3,5-dinitrobenzoic acid with phenazine, 4-hydroxypyridine, and 4-cyanopyridine were studied initially by XPS and then confirmed by X-ray diffraction. In summary, since the N 1s binding energies cluster in a narrow range as cocrystals (398.7-398.9 eV) and salts (400.1-401.1 eV), it is clearly possible to differentiate between cocrystals and salts, but the saltcocrystal continuum values in XPS spectra are clustered in an intermediate range of cocrystals and salts but overlap with those of cocrystal or salt binding energies.

}, issn = {1528-7483}, doi = {10.1021/acs.cgd.0c00661}, author = {Tothadi, Srinu and Shaikh, Tabrez Rafique and Gupta, Sharad and Dandela, Rambabu and Vinod, Chathakudath P. and Nangia, Ashwini K.} } @article {47406, title = {Lithium silicate nanosheets with excellent capture capacity and kinetics with unprecedented stability for high-temperature CO2 capture}, journal = {Chemical Science}, volume = {12}, year = {2021}, month = {APR }, pages = {4825-4835}, type = {Article}, abstract = {

An excessive amount of CO2 is the leading cause of climate change, and hence, its reduction in the Earth{\textquoteright}s atmosphere is critical to stop further degradation of the environment. Although a large body of work has been carried out for post-combustion low-temperature CO2 capture, there are very few high temperature pre-combustion CO2 capture processes. Lithium silicate (Li4SiO4), one of the best known high-temperature CO2 capture sorbents, has two main challenges, moderate capture kinetics and poor sorbent stability. In this work, we have designed and synthesized lithium silicate nanosheets (LSNs), which showed high CO2 capture capacity (35.3 wt\% CO2 capture using 60\% CO2 feed gas, close to the theoretical value) with ultra-fast kinetics and enhanced stability at 650 degrees C. Due to the nanosheet morphology of the LSNs, they provided a good external surface for CO2 adsorption at every Li-site, yielding excellent CO2 capture capacity. The nanosheet morphology of the LSNs allowed efficient CO2 diffusion to ensure reaction with the entire sheet as well as providing extremely fast CO2 capture kinetics (0.22 g g(-1) min(-1)). Conventional lithium silicates are known to rapidly lose their capture capacity and kinetics within the first few cycles due to thick carbonate shell formation and also due to the sintering of sorbent particles; however, the LSNs were stable for at least 200 cycles without any loss in their capture capacity or kinetics. The LSNs neither formed a carbonate shell nor underwent sintering, allowing efficient adsorption-desorption cycling. We also proposed a new mechanism, a mixed-phase model, to explain the unique CO2 capture behavior of the LSNs, using detailed (i) kinetics experiments for both adsorption and desorption steps, (ii) in situ diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy measurements, (iii) depth-profiling X-ray photoelectron spectroscopy (XPS) of the sorbent after CO2 capture and (iv) theoretical investigation through systematic electronic structure calculations within the framework of density functional theory (DFT) formalism.

}, issn = {2041-6520}, doi = {10.1039/d0sc06843h}, author = {Belgamwar, Rajesh and Maity, Ayan and Das, Tisita and Chakraborty, Sudip and Vinod, Chathakudath P. and Polshettiwar, Vivek} } @article {47068, title = {Operando generated ordered heterogeneous catalyst for the selective conversion of CO2 to methanol}, journal = {ACS Energy Letters}, volume = {6}, year = {2021}, month = {FEB }, pages = {509-516}, type = {Article}, abstract = {

The discovery of new materials for efficient transformation of carbon dioxide (CO2) into desired fuel can revolutionize large-scale renewable energy storage and mitigate environmental damage due to carbon emissions. In this work, we discovered an operando generated stable Ni-In kinetic phase that selectively converts CO2 to methanol (CTM) at low pressure compared to the state-of-the-art materials. The catalytic nature of a well-known methanation catalyst, nickel, has been tuned with the introduction of inactive indium, which enhances the CTM process. The remarkable change in the mechanistic pathways toward methanol production has been mapped by operando diffuse reflectance infrared Fourier transform spectroscopy analysis, corroborated by first-principles calculations. The ordered arrangement and pronounced electronegativity difference between metals are attributed to the complete shift in mechanism. The approach and findings of this work provide a unique advance toward the next-generation catalyst discovery for going beyond the state-of-the-art in CO2 reduction technologies.

}, issn = {2380-8195}, doi = {10.1021/acsenergylett.0c02614}, author = {Cherevotan, Arjun and Raj, Jithu and Dheer, Lakshay and Roy, Soumyabrata and Sarkar, Shreya and Das, Risov and Vinod, Chathakudath P. and Xu, Shaojun and Wells, Peter and Waghmare, V, Umesh and Peter, Sebastian C.} } @article {48067, title = {Coordination flexibility aided CO2-specific gating in an iron isonicotinate MOF}, journal = {Chemistry-an Asian Journal}, volume = {17}, year = {2022}, month = {FEB}, pages = {e202101305}, type = {Article}, abstract = {

Coordination flexibility assisted porosity has been introduced into an Iron-isonicotinate metal-organic framework (MOF), (Fe(4-PyC)(2) . (OH). The framework showed CO2-specific gate opening behavior, which gets tuned as a function of temperature and pressure. The MOF {\textquoteleft} s physisorptive porosity towards CO2, CH4, and N-2 was investigated; it adsorbed only CO2 via a gate opening phenomenon. The isonicotinate, representing a borderline soft base, is bound to the hard Fe3+ centre through monodentate carboxylate and pyridyl nitrogen. This moderately weak binding enables isonicotinate to spin like a spindle under the CO2 pressure opening the gate for a sharp increase in CO2 uptake at 333 mmHg (At 298 K, the CO2 uptake increases from 0.70 to 1.57 mmol/g). We investigated the MOF {\textquoteleft} s potential for CO2/N-2 and CO2/CH4 gas separation aided by this gating. IAST model reveals that the CO2/N-2 selectivity jumps from 325 to 3131 when the gate opens, while the CO2/CH4 selectivity increases three times. Interestingly, this Fe-isonicotinate MOF did not follow the trend set by our earlier reported Hard-Soft Gate Control (established for isostructural M2+-isonicotinate MOFs (M=Mg, Mn)). However, we account for this discrepancy using the different oxidation state of metals confirmed by X-ray photoelectron spectroscopy and magnetism.

}, keywords = {CO2 capture, flexible MOF, gating, Isonicotinic}, issn = {1861-4728}, doi = {10.1002/asia.202101305}, author = {Singh, Himan Dev and Nandi, Shyamapada and Chakraborty, Debanjan and Singh, Kirandeep and Vinod, Chathakudath P. and Vaidhyanathan, Ramanathan} } @article {48070, title = {Covalent organic framework with electrodeposited copper nanoparticles - a desirable catalyst for the Ullmann coupling reaction}, journal = {Journal of Materials Chemistry A}, volume = {10}, year = {2022}, month = {JUL}, pages = {15647-15656}, type = {Article}, abstract = {

A covalent organic framework is a porous covalently-linked polymeric assembly built from molecular lego blocks, the monomers. A COF{\textquoteright}s high surface area, ordered pores, and intrinsic low density makes it a perfect heterogeneous catalyst component. Dispersing catalytic metal nanoparticles into the porous COF matrix in a {\textquoteleft}capping-agent-free{\textquoteright} manner can aid the maximal utilization of the active sites. To generate single-site catalysts, metals have been anchored to dense supports, or metal ions have been coordinated to the porous organic framework. The latter has superior atom efficiency and a substrate diffusion advantage. Stably nestling neutral metallic clusters into open-framework supports with no specifically strong binding groups requires a different approach. If infused from extremely dilute electrolytes, metal clusters can be nanoconfined into electrically activated COFs. At low-loadings, it can resemble a single-site catalyst with high atom efficiency. Herein, we report the larger scale synthesis of IISERP-COF15 and electrochemical loading of copper nanoparticles into its pores at loadings as low as 3.34 wt\%. We employed classical Ullmann reactions to adjudge its activity. Typical turnover numbers for the catalysts reported in the literature are approximately 50-100. A Cu@COF shows high activity with a very low catalyst loading of 0.25 mol\% (TON around similar to 300-350 vs. 4 for neat CuCl2 center dot 2H(2)O (homogeneous catalyst) and turnover frequency (similar to 15-17 h(-1))). We recycled it for up to 3 cycles. Furthermore, we report a multi-fold Ullmann reaction producing an unreported hexaaldehyde to demonstrate the latitude of the catalyst. Our work points to the potential of a dilutely loaded metal@COF as a mimic of the single-site catalyst for synthesizing valuable C-O linked molecules. Our findings from computational modeling shed light on the role of the COF as an active nanoporous support for Ullmann C-O coupling.

}, issn = {2050-7488}, doi = {10.1039/d2ta01326f}, author = {Chandran, Chandana and Singh, Himan Dev and Leo, Liya S. and Shekhar, Pragalbh and Rase, Deepak and Chakraborty, Debanjan and Vinod, Chathakudath P. and Vaidhyanathan, Ramanathan} } @article {48099, title = {Green transformation of CO2 to ethanol using water and sunlight by the combined effect of naturally abundant red phosphorus and Bi2MoO6}, journal = {Energy \& Environmental Science}, volume = {15}, year = {2022}, month = {MAY }, pages = {1967-1976}, type = {Article}, abstract = {

Direct photocatalytic conversion of CO2 to ethanol remains a scientific challenge because of the sluggish kinetics of C-C coupling and complex multielectron transfer processes. To achieve a green transformation of CO2 to C1+ products using naturally abundant sunlight and water requires the smart design of an efficient catalyst by selecting the right combination of atoms either in elemental or in compound form. Herein, we report a composite photocatalyst composed of earth abundant red phosphorus (RP) in nano-sheet morphology decorated with Bi2MoO6 nano-particles. The composite synthesised by a facile ultrasonication method produces 51.8 mu mol g(-1) h(-1) of ethanol from CO2. The ability of RP for the conversion of CO2 to C1 has been altered by the introduction of Bi2MoO6. In situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) and Kinetic Isotopic Effect (KIE) analysis shed light on the mechanistic pathway, which propose that the presence of Bi-Mo dual sites play a crucial role in the C-C coupling toward the formation of ethanol. Spectroscopic evidence and isotope labeling experiments suggest that the intermediate OCH3* is the key active species for ethanol formation via self-coupling followed by proton transfer.

}, issn = {1754-5692}, doi = {10.1039/d1ee02976b}, author = {Das, Risov and Das, Kousik and Ray, Bitan and Vinod, Chathakudath P. and Peter, Sebastian C.} } @article {48210, title = {Improvement in oxygen evolution performance of NiFe layered double hydroxide grown in the presence of 1T-Rich MoS2}, journal = {ACS Applied Materials \& Interfaces}, volume = {14}, year = {2022}, month = {JUL}, pages = {31951-31961}, type = {Article}, abstract = {

NiFe layered double hydroxide (NiFe LDH) grown in the presence of MoS2 (rich in 1T phase) shows exceptional performance metrics for alkaline oxygen evolution reaction (OER) in this class of composites. The as-prepared NiFe LDH/MoS2 composite (abbreviated as MNF) exhibits a low overpotential (eta(10)) of 190 mV; a low Tafel slope of 31 mV dec(-1); and more importantly, a high stability in its performance manifested by the delivery of current output for 45 h. It is important to note that this could be achieved with an exceedingly low loading of 0.14 mg cm(-2). The mass activity of this composite (97 A g(-1)) is about 14 times greater than that of the conventional RuO2 (7 A g(-1) ) at eta = 200 mV. When normalized with respect to the total metal content, a mass activity of 1000 A g(-1) (eta = 300 mV) was achieved. Impedance analysis further reveals that the significant reduction in charge-transfer resistance and hence high current density (5 times greater as compared to NiFe LDH at eta = 300 mV) observed for MNF is associated with interfacial adsorption kinetics of intermediates (R-1). Significant enhancement in the intrinsic activity of MNF over LDH has been observed through normalization of current with the electrochemically active surface area. Computational studies suggest that the Ni centers in the composite act as the active sites for OER, which is well-corroborated with the observed postreaction appearance of Ni3+ species.

}, keywords = {Impedance, LDH-MoS2 hybrid electrocatalyst, mass activity, OER, overpotential}, issn = {1944-8244}, doi = {10.1021/acsami.2c06210}, author = {Chakraborty, Soumita and Marappa, Shivanna and Agarwal, Sakshi and Bagchi, Debabrata and Rao, Ankit and Vinod, Chathakudath P. and Peter, Sebastian C. and Singh, Abhishek and Eswaramoorthy, Muthusamy} } @article {48188, title = {Influence of support textural property on CO2 to methane activity of Ni/ SiO2 catalysts}, journal = {Applied Catalysis B-Environmental}, volume = {317}, year = {2022}, month = {NOV}, pages = {121692}, type = {Article}, abstract = {

In this work, we elucidated the role of physicochemical textural properties of inert support on the catalyst ac-tivity by impregnating Ni on ordered mesoporous silica (SBA-15 and MCM-41) and non-mesoporous silica (nMPS). The catalyst Ni/SBA-15 exhibited the best CO2 conversion (83\%) and product selectivity (99.9 \%) followed by Ni/MCM-41 and the least by Ni/nMPS. The difference in the nature of the catalyst, degree of nanoparticle distribution and nanoparticle encapsulation by different silica support were studied by N2 adsorption-desorption and X-ray photoelectron spectroscopy (XPS) experiments. The Operando Diffused Reflec-tance Infrared Fourier Transform Spectroscopy were used to understand the variance in reaction pathway which is accredited to the textural properties of the support. The SBA-15 supported Ni catalyst followed dissociative CO pathway while MCM-41 and nMPS reacted through associative formate mechanism as major pathway. These findings provide a novel perspective on CO2 hydrogenation over Ni-silica, allowing us to tune both activity and selectivity.

}, keywords = {CO2 methanation, DRIFTS, Mesoporous silica support, Textural properties}, issn = {0926-3373}, doi = {10.1016/j.apcatb.2022.121692}, author = {Cherevotan, Arjun and Ray, Bitan and Churipard, Sathyapal R. and Kaur, Komalpreet and Gautam, Ujjal K. and Vinod, Chathakudath P. and Peter, Sebastian C.} } @article {48415, title = {Noble-metal-free heterojunction photocatalyst for selective CO2 reduction to methane upon induced strain relaxation}, journal = {ACS Catalysis}, volume = {12}, year = {2022}, month = {JAN }, pages = {687-697}, type = {Article}, abstract = {

Sunlight-driven CO2 hydrogenation has drawn tremendous attention. However, selective CH4 formation via CO2 photoreduction is very challenging. Herein, we report a metal oxide semiconductor heterojunction consisting of BiVO4 and WO3 as a photocatalyst for the efficient conversion of carbon dioxide (CO2) selectively to methane (105 mu mol g(-1) h(-1)) under visible light in the absence of a sacrificial agent. Wise selection of the reaction medium and the strategically tuned heterojunction upon strain relaxation suppresses the competitive hydrogen generation reaction. The detailed photophysical, photoelectrochemical, and X-ray absorption spectroscopy studies pointed to the Z-scheme mechanism of electron transfer, which favors superior electron and hole separation compared to the individual components of the composite catalyst and other well-known photocatalysts reported for CO2 reduction. The observations are further corroborated by experimental diffuse reflectance infrared Fourier transform spectroscopy and theoretical density-functional theory calculations, which reveal that the heterojunction has a lower free-energy barrier for CO2 conversion to CH4 due to the larger stabilization of the *CH2O intermediate on the strain-relaxed heterojunction surface, in comparison to the pristine BiVO4 surface. The present work provides fundamental insights for constructing high-performance heterojunction photocatalysts for the selective conversion of CO2 to desired chemicals and fuels.

}, keywords = {CO2 reduction, heterostructure, methane, Photocatalysis, Z-scheme}, issn = {2155-5435}, doi = {10.1021/acscatal.1c04587}, author = {Das, Risov and Sarkar, Shreya and Kumar, Ritesh and Ramarao, Seethiraju D. and Cherevotan, Arjun and Jasil, Mohammed and Vinod, Chathakudath P. and Singh, Abhishek Kumar and Peter, Sebastian C.} } @article {48094, title = {Potential- and time-dependent dynamic nature of an oxide-derived pdin nanocatalyst during electrochemical CO2 reduction}, journal = {ACS Nano}, volume = {16}, year = {2022}, month = {APR}, pages = {6185-6196}, type = {Article}, abstract = {

Electrochemical reduction of CO2 into valuable fuels and chemicals is a promising route of replacing fossil fuels by reducing CO2 emissions and minimizing its adverse effects on the climate. Tremendous efforts have been carried out for designing efficient catalyst materials to selectively produce the desired product in high yield from CO2 by the electrochemical process. In this work, a strategy is reported to enhance the electrochemical CO2 reduction reaction (ECO2RR) by constructing an interface between a metal-based alloy (PdIn) nanoparticle and an oxide (In2O3), which was synthesized by a facile solution method. The oxide-derived PdIn surface has shown excellent eCO(2)RR activity and enhanced CO selectivity with a Faradaic efficiency (FE) of 92.13\% at -0.9 V (vs RHE). On the other hand, surface PdO formation due to charge transfer on the bare PdIn alloy reduces the CO2RR activity. With the support of in situ (EXAFS and IR) and ex situ (XPS, Raman) spectroscopic techniques, the optimum presence of the Pd-In-O interface has been identified as a crucial parameter for enhancing eCO(2)RR toward CO in a reducing atmosphere. The influence of eCO(2)RR duration is reported to affect the overall performance by switching the product selectivity from H-2 (from water reduction) to CO (from eCO(2)RR) on the oxide-derived alloy surface. This work also succeeded in the multifold enhancement of the current density by employing the gas diffusion electrode (GDE) and optimizing its process parameters in a flow cell configuration.

}, keywords = {CO2 reduction, Electrochemistry, heterostructure interface, in situ mechanism, nanocatalyst}, issn = {1936-0851}, doi = {10.1021/acsnano.1c11664}, author = {Bagchi, Debabrata and Sarkar, Shreya and Singh, Ashutosh Kumar and Vinod, Chathakudath P. and Peter, Sebastian C.} } @article {48181, title = {Tuning the hybridization and charge polarization in metal nanoparticles dispersed over Schiff base functionalized SBA-15 enhances CO2 capture and conversion to formic acid}, journal = {Journal of Materials Chemistry A}, volume = {10}, year = {2022}, month = {SEP}, pages = {18354-18362}, type = {Article}, abstract = {

Different Schiff base functionalized SBA-15 materials were synthesized through condensation reactions between 3-aminopropyltriethoxysilane (APTES) and different aldehydes (glutaraldehyde and butyraldehyde) over a mesoporous silica, SBA-15 (APTES-GLU/SBA-15 and APTES-BUT/SBA-15). Both static and dynamic experiments have been used for testing the CO2 capture efficiency of these materials. The hybridization of the N atom in APTES has been tuned from sp(3) to sp(2) upon condensation facilitating optimum CO2 capture in the direct synthesis of APTES-GLU/SBA-15. The undesirable oxides of nitrogen have been removed during the synthesis process to improve the CO2 capture efficiency. These materials were employed as supports for Pd-Ag and Pd-Ni bimetallic systems for the selective conversion of the captured CO2 to formic acid (FA) in 0.5 M KHCO3 solution. The Pd-Ni catalyst system exhibited enhanced CO2 to FA conversion activity compared to other heterogeneous systems, which is similar to 4 times better than that of the Pd-Ag system in this study. The X-ray absorption studies over the catalyst material confirmed that the relatively electron-deficient Ni in Pd-Ni compared to Ag in Pd-Ag favoured higher charge polarization between the metals in the Pd-Ni system enhancing the CO2 to FA conversion. The experimental observations are well supported by the DFT calculations.

}, issn = {2050-7488}, doi = {10.1039/d2ta03690h}, author = {Cherevotan, Arjun and Ray, Bitan and Yadav, Anish and Bagchi, Debabrata and Singh, Ashutosh Kumar and Riyaz, Mohd and Churipard, Sathyapal R. and Naral, Vinay and Kaur, Komalpreet and Gautam, Ujjal K. and Vinod, Chathakudath P. and Peter, Sebastian C.} } @article {48450, title = {Intrinsic charge polarization in Bi19S27Cl3 nanorods promotes selective C-C coupling reaction during photoreduction of CO2 to ethanol}, journal = {Advanced Materials}, volume = {35}, year = {2023}, month = {FEB}, type = {Article}, abstract = {

Obtaining multi-carbon products via CO2 photoreduction is a major catalytic challenge involving multielectron-mediated C-C bond formation. Complex design of multicomponent interfaces that are exploited to achieve this chemical transformation, often leads to untraceable deleterious changes in the interfacial chemical environment affecting CO2 conversion efficiency and product selectivity. Alternatively, robust metal centers having asymmetric charge distribution can effectuate C-C coupling reaction through the stabilization of intermediates, for desired product selectivity. However, generating inherent charge distribution in a single component catalyst is a difficult material design challenge. Here, a novel photocatalyst, Bi19S27Cl3, is presented which selectively converts CO2 to a C-2 product, ethanol, in high yield under visible light irradiation. Structural analysis through transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy reveals the presence of charge polarized bismuth centers in Bi19S27Cl3. The intrinsic electric field induced by charge polarized bismuth centers renders better separation efficiency of photogenerated electron-hole pair. Furthermore, charge polarized centers yield better adsorption of CO* intermediate and accelerate the rate determining C-C coupling step through the formation of OCCOH intermediate. Formation of these intermediates is experimentally mapped by in situ Fourier-transform infrared spectroscopy and further confirmed by theoretical calculation.

}, keywords = {C-C coupling, charge polarization, CO2 reduction, Ethanol, Photocatalysis}, issn = {0935-9648}, doi = {10.1002/adma.202205994}, author = {Das, Kousik and Das, Risov and Riyaz, Mohd and Parui, Arko and Bagchi, Debabrata and Singh, Ashutosh Kumar and Singh, Abhishek Kumar and Vinod, Chathakudath P. and Peter, Sebastian C.} } @article {48491, title = {Wadsworth-emmons reaction by using the fluorapatite catalyst: kinetic studies}, journal = {Industrial \& Engineering Chemistry Research}, volume = {62}, year = {2023}, month = {MAY }, pages = {7901-7911}, type = {Article}, abstract = {

Wadsworth-Emmons reaction was successfully carriedout byusing the fluorapatite (FAP) catalyst. The reaction of 2-methoxybenzaldehydeand triethylphosphonoacetate using FAP afforded \& alpha;,\& beta;-unsaturatedester with 100\% conversion and 80\% selectivity. A kinetic model wasvalidated at different temperatures by Langmuir-Hinshelwood-Hougen-Watson(LHHW), and the absence of mass transfer resistance was verified bythe Weisz Prater criterion. The effect of different catalysts, temperature,catalyst loading, solvent, mole ratio, and speed of stirring was studied.The FAP catalyst was characterized by Fourier transform infrared spectroscopy,Brunauer-Emmett-Teller method, nitrogen adsorption-desorption,transmission electron microscopy, energy-dispersive X-ray spectroscopy,temperature programmed desorption (TPD-NH3), X-ray diffraction,and X-ray photoelectron spectroscopy. The FAP catalyst was found tobe stable up to three recycles with no loss in activity.

}, issn = {0888-5885}, doi = {10.1021/acs.iecr.3c00407}, author = {Vishwakarma, Rakhi and Vinod, Chathakudath P. and Rathod, Virendra and Kantam, Mannepalli Lakshmi} }