@article { ISI:000350685400013, title = {Renewable fuels from biomass-derived compounds: Ru-containing hydrotalcites as catalysts for conversion of HMF to 2,5-dimethylfuran}, journal = {Catalysis Science \& Technology}, volume = {5}, number = {3}, year = {2015}, month = {MAR}, pages = {1463-1472}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Production of transportation fuels from renewable biomass is hugely important considering the current ecological concerns over CO2 built up in the atmosphere. Ruthenium-containing hydrotalcite (HT) catalysts were applied for the selective hydrogenolysis of biomass-derived 5-hydroxymethylfurfural (HMF) to 2,5-dimethylfuran (DMF). Structural and morphological features of the catalysts were examined using various physico-chemical characterization techniques. The influence of various reaction parameters, such as reaction temperature, solvent, Ru content of the catalyst, etc., was investigated with respect to HMF conversion and DMF yield. The study clearly shows that well-dispersed Ru nanoparticles are highly active and selective in the conversion of HMF to DMF. A catalyst containing only 0.56 wt\% Ru converted 100 mol\% HMF to yield 58 mol\% DMF. This catalyst was found to be recyclable as the activity was retained even after five cycles of reaction. 2-Propanol was found to be a good solvent as it helped to improve DMF yield through transfer hydrogenation. Based on the results of the investigations, a reaction pathway for the conversion of HMF to DMF was proposed for the present Ru-based catalyst system.

}, issn = {2044-4753}, doi = {10.1039/c4cy01376j}, author = {Nagpure, Atul S. and Venugopal, Ashok Kumar and Lucas, Nishita and Manikandan, Marimuthu and Thirumalaiswamy, Raja and Chilukuri, Satyanarayana V.} } @article { ISI:000374626200020, title = {Role of surface synergistic effect on the performance of Ni-based hydrotalcite catalyst for highly efficient hydrogenation of furfural}, journal = {Journal of Molecular Catalysis A-Chemical}, volume = {417}, year = {2016}, month = {JUN}, pages = {153-162}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

The selective vapor phase hydrogenation of furfural at ambient pressure has been investigated using a facile and robust hydrotalcite derived Ni containing mixed oxide catalyst. The systematic characterization results conferred that the difficulty in the reduction of Ni species due to the strong interaction between Ni and support, which facilitated from the homogeneous distribution of hydrotalcite structure. It was also found that the structure and catalytic performance of the catalysts were greatly influenced by Ni loading. Through fine-tuned surface elemental sites and reaction conditions, furfural conversion of 98\% with 95\% of furfuryl alcohol selectivity was achieved over a MAN-2 catalyst containing two molar ratio of Ni. The results have demonstrated that the incorporation of Mg significantly enhances the Ni-support interaction, Ni dispersion and catalytic performance. The high efficiency of the Ni-based hydrotalcite derived catalyst was mainly attributed to the surface synergistic interaction between the catalytically active metallic Ni sites and the strong basic sites, which furnished an eco-benign and sustainable catalyst for the selective hydrogenation of furfural. Furthermore, the spent catalyst analysis substantiated that no significant difference in the catalyst phase was observed even after 48 h of reaction stream. (C) 2016 Elsevier B.V. All rights reserved.

}, keywords = {alcohol-hydrotalcites-selective, Biomass-frurfural-furfuryl, Hydrogenation}, issn = {1381-1169}, doi = {10.1016/j.molcata.2016.03.019}, author = {Manikandan, Marimuthu and Venugopal, Ashok Kumar and Prabu, Kandasamy and Jha, Ratnesh Kumar and Thirumalaiswamy, Raja} } @article {47578, title = {Active K-OMS-2 supported catalyst for hydrogenolysis of glycerol}, journal = {ChemistrySelect}, volume = {6}, year = {2021}, month = {SEP}, pages = {8700-8708}, type = {Article}, abstract = {Propanediols are very important chemical intermediates, which need to be prepared through commercially viable routes. Cryptomelane type octahedral molecular sieve-2 (K-OMS-2), a cheap and environmentally benign microporous oxide was employed to support Ru and used as a catalyst to get 1,2-propanediol (1,2-PDO) selectively through hydrogenolysis of glycerol. Three catalysts with different Ru content were prepared and evaluated for glycerol hydrogenolysis. Among these, 1 wt.\% Ru-K-OMS-2 showed reasonably good activity towards 1,2-PDO formation under moderate reaction conditions even at lower Ru loading (0.9 wt.\%). When other metals such as Cu and Ni were supported on K-OMS-2, their performance was inferior compared to Ru-supported catalysts. All the catalysts were characterized using various physicochemical techniques like XRD, N-2-sorption, TPD, H-2-TPR, TGA, ICP-OES, FE-SEM and TEM. The enhanced catalytic activity with the 1 wt.\%Ru-K-OMS-2 catalyst was attributed to the better Ru metal dispersion, higher active metal surface area, basic strength, and porosity of the support. The catalyst was found to be recyclable. Analysis of spent catalyst by TEM showed disintegration of Ru nanoparticles to smaller ones, under high H-2 pressure at the reaction temperature. Smaller Ru particles are expected to promote C-C bond cleavage thus suppressing 1,2-PDO formation. Furthermore, a relationship between the TOF value, Ru nanoparticles size, and the basic strength of the catalysts was established, which provides dipper insight into the different catalytic behavior of the catalysts.}, keywords = {Glycerol, Hydrogenolysis, octahedral molecular sieves, Propanediols, selectivity}, issn = {2365-6549}, doi = {10.1002/slct.202101664}, author = {Gogoi, Pranjal and Chilukuri, Satyanarayana and Thirumalaiswamy, Raja} } @article {47094, title = {Promoted mesoporous Fe-alumina catalysts for the non-oxidative dehydrogenation of isobutane}, journal = {Catalysis Communications}, volume = {150}, year = {2021}, month = {FEB}, pages = {106263}, type = {Article}, abstract = {

Production of isobutene is commercially consequential and highly demanding from the end-use industries being a key platform molecule as well as an intermediate for a variety of value-added chemicals. Traditionally, isobutene is prepared via steam cracking and fluid catalytic cracking methods. However, the catalysts used in these conventional methods have disadvantages like coke formation, sintering, etc. In this study, the catalytic non-oxidative dehydrogenation of isobutane over acidic, alkaline, and noble metal promoted mesoporous iron-doped catalysts was investigated. Iron doping has a significant function in controlling isobutene selectivity. The synthesis method is crucial to achieve successful metal doping in the mesoporous alumina matrix. Promoted catalysts exhibited a notable difference in isobutane conversion with a marginal change in dehydrogenation selectivity. Silver promoted catalyst showed slightly higher isobutene yield due to the optimal catalytic properties. This catalyst was stable for a considerable duration, and coke deposition, as well as particle agglomeration, were observed to faintly inhibit the catalytic activity.

}, keywords = {iron, Isobutane, Isobutene, Mesoporous alumina, Non-oxidative dehydrogenation}, issn = {1566-7367}, doi = {10.1016/j.catcom.2020.106263}, author = {Venugopalan, Aswathy Thareparambil and Kandasamy, Prabu and Gupta, Nikitra Nihalchand and Thirumalaiswamy, Raja} } @article {47076, title = {Utilizing the oxygen carrier property of cerium iron oxide for the low-temperature synthesis of 1,3-butadiene from 1-butene}, journal = {Catalysis Letters}, volume = {151}, year = {2021}, month = {OCT}, pages = {3057-3066}, type = {Article}, abstract = {

Low-temperature oxidative dehydrogenation (ODH) of 1-butene to 1,3-butadiene is one of the challenging reactions in the polymer industry. Towards this a highly dispersed cerium iron oxide was synthesized by citrate gel combustion method and employed for the synthesis of 1,3-butadiene (BD) from 1-butene. The reaction was carried out at low temperature under an oxygen-free atmosphere in a continuous flow mode fixed bed reactor. A decrease in the lattice parameters observed from PXRD and high-resolution TEM analysis proved that iron occupies cerium sites in the crystal lattice. XPS, TPR, and oxygen uptake studies quantified the nature and abundance of different oxygen species. ODH was observed through consuming lattice oxygens. The vacancies generated could be filled by re-oxidation with an external supply of oxygen which will restore the catalytic activity demonstrating the Mars van Krevelen mechanism. [GRAPHICS] .

}, keywords = {1, 1-butene, 3-butadiene, Cerium, iron, Lattice oxygen, oxidative dehydrogenation}, issn = {1011-372X}, doi = {10.1007/s10562-020-03512-5, Early Access Date = FEB 2021}, author = {Venugopalan, Aswathy T. and Kandasamy, Prabu and Gogoi, Pranjal and Ratneshkumar, Jha and Thirumalaiswamy, Raja} } @article {48021, title = {Microwave-assisted selective N-alkylation of aniline over molybdenum supported catalyst}, journal = {Catalysis Communications}, volume = {168}, year = {2022}, month = {AUG}, pages = {106464}, type = {Article}, abstract = {

Selective N-alkylation of aniline is a tough and challenging reaction due to over alkylation, therefore, catalyst with specific characteristics is needed to accomplish such transformations. In this work, a series of catalysts with molybdenum supported on alumina are prepared and subjected to various reaction conditions, out of which 30 PMA (Phosphomolybdic acid) showed the best result due to its proper combination of acidic sites. This reaction is sustainable and environmentally friendly as it is carried out with methanol as an alkylating source in the presence of microwave radiation at low temperature. The reaction data was compared with various other reactor systems too.

}, issn = {1566-7367}, doi = {10.1016/j.catcom.2022.106464}, author = {Bhatkar, Akash and Mane, Samruddhi and Mekala, Siva Prasad and Gogoi, Pranjal and Mohapatra, Gourab and Ramakrishnan, Archana and Marimuthu, Prabu and Thirumalaiswamy, Raja} } @article {48217, title = {Synthesis and crystal structures of Mn(II) and Co(II) complexes as catalysts for oxidation of cyclohexanone}, journal = {Inorganics}, volume = {10}, year = {2022}, month = {JUL}, pages = {100}, type = {Article}, abstract = {

The global demand on adipic usage in the production of plasticizers and synthetic polyamide is increasing. In line with the search for an efficient and energy-conserving way to isolate adipic acid (AA) in good yields, this paper introduces the oxidization of cyclohexanone utilizing two new coordination compounds, [Mn(2,6-pydc)(2)](imi) (1) and [Co(H(2)pza)(2)(H2O)(2)(NO3)].NO3 (2), as catalysts. Compounds 1 and 2 were synthesized by room temperature and refluxing methods, and characterized by spectral analyses (IR and UV-Vis.), SEM, BET, TGA, elemental, and X-ray crystallography. The single crystal structure of compound 1 revealed that pyridinedicarboxylate (2,6-pydc) and imidazole (imi) moieties were coordinated to the Mn(II) atom through imine nitrogen and deprotonated oxygen atoms, to form an undistorted octahedral coordination geometry with the N2O4 donor set. The axial and equatorial planes containing O2, O4, O5, and O7 atoms were from two adjacent 2,6-pydc ligands which formed the unidendate donor ligand; imi, on the other hand, acted as a bidendate donor ligand. For compound 2, the Co(II) atom was being coordinated by two pyrazinamide (H(2)pza) moieties, which acted as an unidendate donor ligand; two water molecules occupying the axial position, and one nitrate molecule occupying the apical position, were within the coordination sphere; a nitrate molecule was disordered outside the coordination sphere. The distance, 4.658 angstrom, between the Co1 atom and the N8 atom of the uncoordinated nitrate molecule, was within the range reported elsewhere. Cyclohexanone peroxidation experiments revealed that compound 1 exhibited unique catalytic performance by giving a 72.8\% yield in adipic acid, in comparison to the 71.3\% yield obtained with compound 2. The yields in AA were maintained by way of recyclability evaluation. The reaction kinetics of compound 2 gave less activation energy, E-a 2938 J mol(-1), while the thermodynamic parameters indicated that the chemical reactivity of cyclohexanone on the active surfaces of compounds 1 and 2 was via monolayer physisorption.

}, keywords = {cobalt, Complexes, cyclohexanone, Imidazole, managanese, Oxidation, pyrazinamide, pyridinedicarboxylate}, doi = {10.3390/inorganics10070100}, author = {Tella, Adedibu C. and Isaac, Aaron Y. and Clayton, Hadley S. and Ogunlaja, Adeniyi S. and Venugopalan, Aswathy T. and Prabu, Marimuthu and Thirumalaiswamy, Raja} }