Faculty Publications
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Item A straightforward preparation of levulinic esters from biorenewable levulinic acid using methanesulfonic acid supported on silica gel (MSA-SG) as an efficient heterogeneous catalyst(Elsevier Ltd, 2023) Vinod, N.; Bandibairanahalli Onkarappa, S.; Madhwaraj Girija, V.; Dutta, S.The present work reports methanesulfonic acid supported on silica gel (MSA-SG) as an inexpensive heterogeneous solid acid catalyst for the high-yielding production of various alkyl levulinates from biomass-derived levulinic acid. The catalyst was characterized by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDX). The reactions were conducted in a batch-type glass pressure reactor under conventional heating. The esterification reaction was optimized on temperature, duration, and catalyst loading. The optimized reaction conditions (120 °C, 8 h, 8 wt% MSA-SG) afforded methyl- to butyl levulinate in excellent isolated yields (≥90 %). The catalyst was filtered, and the products were purified by simply evaporating the excess alcohol reagent. © 2022Item Recent advances in the preparation of levulinic esters from biomass-derived furanic and levulinic chemical platforms using heteropoly acid (HPA) catalysts(Elsevier B.V., 2021) Bhat, N.S.; Mal, S.S.; Dutta, S.The esters of biomass-derived levulinic acid (LA) have several potential applications, including cleaner-burning fuel additive, green solvent, fragrance ingredient, and a renewable chemical intermediate for downstream value addition. The levulinic esters (LEs) can be prepared by the acid-catalyzed alcoholysis of the biomass-derived furanic and levulinic chemical platforms such as LA, furfuryl alcohol (FAL), 5-(hydroxymethyl)furfural (HMF), and angelica lactone (AGL). The acid-catalyzed deconstruction of carbohydrates in an alcoholic medium affords the one-pot preparation of LEs. Choosing the right catalyst is of paramount importance for synthesizing LEs from both the economic and environmental perspectives. In this regard, heteropoly acids (HPAs), a class of polyoxometalates (POMs) bearing protons as the counter cation, have found widespread applications as acid catalysts in various organic transformations. HPAs are blessed with conducive properties such as controlled Brønsted and Lewis acidity, high thermal stability, robust structural features, non-toxic nature, tunable solubility, and less corrosiveness. Over the past several years, HPAs have found extensive applications as efficient and environment-friendly catalysts in biorefinery operations, including the synthesis of LEs. At this juncture, it is imperative to ascertain the achievements in this field to date and re-evaluate the challenges. This review attempts to provide up-to-date information about the preparation of LEs using HPA-based catalysts, critically analyze the literature cited, draw conclusions, and propose future prospects. © 2021 Elsevier B.V.Item Evaluation of methyl esters of mahua oil (mahua indica) as diesel fuel(2008) Kapilan, N.; Reddy, R.P.There is increasing interest in India for suitable alternative fuels that are environment friendly. This search has led to mahua oil (MO) as one alternative for diesel fuel in India. Mahua oil methyl esters (MOME) were prepared by transesterification using potassium hydroxide (KOH) as catalyst and nuclear magnetic resonance (NMR) testing was done to determine the conversion of vegetable oil to biodiesel (MOME). The properties of MOME were close to those of diesel oil. Engine testing was conducted using a single-cylinder 4-stroke direct-injection, constant-speed compression-ignition diesel engine using MO, MOME and B20 as fuels. The engine ran smoothly with MOME and B20, but heavy smoke emissions were observed when MO was used as fuel. © 2007 AOCS.Item Experimental investigation of esters of mahua oil as an alternative fuel for dual fuel engine(2008) Reddy, P.B.; Kapilan, N.; Reddy, R.P.In the present work, an attempt was made to use methyl ester of mahua oil (MEMO) as substitute for dieselin dual fuel engine. A four stroke single cylinder engine was modified to work in dual fuel mode. From the test results, it was observed that the MEMO could be used as pilot fuel in dual fuel engine. At lower loads, diesel gave higher brake thermal efficiency. But at higher loads, biodiesel resulted in brake thermal efficiency comparable with diesel and lower smoke and oxides of nitrogen emissions. From the test results, it was concluded that MEMO could be used as a substitute for diesel in dual fuel engine.Item Bio-fuel variants for use in CI engine at design and off-design regimes: An experimental analysis(2008) Bekal, S.; Ashok Babu, T.P.A.In this work an attempt has been made to study the ester based fuel variants derived from edible and inedible oil sources for identifying the most appropriate fuel variant and operating mode for running a CI engine based on performance and emission parameters. The twenty four fuel variants tested included esters obtained from the edible sunflower oil, inedible pongamia oil, and their higher and lower proportional blends with diesel. Besides, several other fuel variants obtained from the emulsification of water-in-ester (W/E) with different water proportions have been tested. Basing upon three operational variables, namely, injection timing, injection pressure, and load, comparisons are made in aspects of smoke emissions, NOX emissions, BSEC, and exhaust gas temperatures at the best injection timing. 21.5°, 23°, 24.5° and 27.5° bTDC as the four injection timings and 190, 220 and 250 bar as three injection pressures are considered for the overall study. The 264 sets of experiments conducted with these combinations, focussing on the full and partial load characteristics of the engine, show that both sunflower and pongamia oil esters exhibited similar characteristics in their engine performance, and in both the cases the best BSEC occurred with 220 bar injection pressure for most of the fuel variants, and for straight fuels the ideal injection timing found to be slightly retarded (1.5° crank angle) compared to diesel. However, 24.5° bTDC, normal for the engine, was found to be the most appropriate for the lower blends like B2 (2% ester by volume), B5 and emulsion with 10% water proportion. © 2008 Elsevier Ltd. All rights reserved.Item 6BTA 5.9 G2-1 Cummins engine performance and emission tests using methyl ester mahua (Madhuca indica) oil/diesel blends(2009) Godiganur, S.; Suryanarayana Murthy, C.H.; Reddy, R.P.Neat mahua oil poses some problems when subjected to prolonged usage in CI engine. The transesterification of mahua oil can reduce these problems. The use of biodiesel fuel as substitute for conventional petroleum fuel in heavy-duty diesel engine is receiving an increasing amount of attention. This interest is based on the properties of bio-diesel including the fact that it is produced from a renewable resource, its biodegradability and potential to exhaust emissions. A Cummins 6BTA 5.9 G2- 1, 158 HP rated power, turbocharged, DI, water cooled diesel engine was run on diesel, methyl ester of mahua oil and its blends at constant speed of 1500 rpm under variable load conditions. The volumetric blending ratios of biodiesel with conventional diesel fuel were set at 0, 20, 40, 60, and 100. Engine performance (brake specific fuel consumption, brake specific energy consumption, thermal efficiency and exhaust gas temperature) and emissions (CO, HC and NOx) were measured to evaluate and compute the behavior of the diesel engine running on biodiesel. The results indicate that with the increase of biodiesel in the blends CO, HC reduces significantly, fuel consumption and NOx emission of biodiesel increases slightly compared with diesel. Brake specific energy consumption decreases and thermal efficiency of engine slightly increases when operating on 20% biodiesel than that operating on diesel. © 2008 Elsevier Ltd. All rights reserved.Item Performance and emission characteristics of a Kirloskar HA394 diesel engine operated on fish oil methyl esters(2010) Godiganur, S.; Suryanarayana Murthy, Ch.; Reddy, R.P.The high viscosity of fish oil leads to problem in pumping and spray characteristics. The inefficient mixing of fish oil with air leads to incomplete combustion. The best way to use fish oil as fuel in compression ignition (CI) engines is to convert it into biodiesel. It can be used in CI engines with very little or no engine modifications. This is because it has properties similar to mineral diesel. Combustion tests for methyl ester of fish oil and its blends with diesel fuel were performed in a kirloskar H394 DI diesel engine, to evaluate fish biodiesel as an alternative fuel for diesel engine, at constant speed of 1500 rpm under variable load conditions. The tests showed no major deviations in diesel engine's combustion as well as no significant changes in the engine performance and reduction of main noxious emissions with the exception on NOx. Overall fish biodiesel showed good combustion properties and environmental benefits. © 2009 Elsevier Ltd. All rights reserved.Item Design and Synthesis of New Amides and Thioamides Derived from 3,4-Ethylenedioxythiophene as Potential Anticonvulsants(2010) Kulandasamy, R.; Vasudeva Adhikari, A.V.; Stables, J.P.Five new series of 3,4-ethylenedioxythiophene derivatives carrying important pharamacophores, viz., amide, ester, ether and active secondary aryl moieties have been designed and synthesized through multistep reactions starting from thiodiglycolic ester and diethyl oxalate. They have been characterized by elemental and spectral data. All the target compounds have been screened for their anticonvulsant activity at three different models viz. maximal electroshock (MES), subcutaneous metrazole (scMET), and 6 Hz screen and evaluated for their neurotoxicity in rotorod model. Compound 6a emerged as lead with no neurotoxicity. All the five series of compounds are safe in the toxicity studies at the maximum dose of 300 mg/kg of body weight. Amongst the tested compounds, the ester pharmacophore with thioamide fragment has showed better activity than the other analogs.Item An analysis of cycle-by-cycle fluctuation in combustion parameter in CI engine operation for various bio-fuels(2011) Bekal, S.; Ashok Babu, T.P.A.The cycle-by-cycle fluctuations in peak pressure of combustion in a CI engine were studied for lower and higher blends of diesel and ester, and water-in-ester emulsions, at four injection timings and three injection pressures using coefficient of variation. The sunflower ester-diesel blends are found to have lower cycle-by-cycle fluctuations than pongemia ester-diesel blends. The fluctuations are found to be higher than that of diesel for higher blend proportions of ester. The water-in-ester emulsion show higher cycle-by-cycle fluctuations than that of ester-diesel blends. In most cases, the Brake specific energy consumption is also found to be higher where the coefficient of variation has higher values. Copyright © Taylor & Francis Group, LLC.Item Kinetics of esterification of acetic acid with methanol in the presence of ion exchange resin catalysts(2011) JagadeeshBabu, P.E.; Sandesh, K.; Saidutta, M.B.Esterification kinetics of acetic acid with methanol was studied with solid acid catalyst in an isothermal batch reactor at 333-353 K. Different types of ion exchange catalyst (Indion 130, Indion 190, and Amberlyst 15 wet) were used for the esterification of acetic acid. It was found that Indion 130 was an effective catalyst for acetic acid esterification. The effects of stirrer speed, reaction temperature, initial reactant concentration, and catalyst loading on reaction rate were investigated and optimized. Temperature dependence of the reaction rates and activation energies was determined by an Arrhenius plot. A complete kinetic equation for describing the reaction catalyzed by Indion 130 was developed. This equation can be used in the simulation and design of the catalytic distillation column for the synthesis of methyl acetate. © 2011 American Chemical Society.