Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
16 results
Search Results
Item A simple, rapid, selective and sensitive spectrophotometric method for the determination of palladium is proposed using piperonal thiosemicarbazone (PATS) as a reagent. The reagent forms a 1:2 complex (Pd:Reagent) with palladium. The yellow complex is soluble in 32-40% ethanol and has an absorption maximum at 363 nm. Beer's law is obeyed upto 3.85 ppm of palladium and the optimum concentration range is 0.5-2.45 ppm of Pd. The molar absorptivity and Sandell's sensitivity are 3. 80 x 104 dm3 mol-1 cm -1 and 2.8 x 10-3 ?g cm-2, respectively. The experimental conditions for complete colour development and the interference from various ions are investigated. The method is used for the determination of palladium in its complexes and synthetic mixtures.(Spectrophotometric determination of palladium(II) using piperonal thiosemicarbazone) Shetty, P.; Nityananda Shetty, A.N.; Gadag, R.V.2003Item Spectrophotometric determination of platinum(IV) in alloys, complexes, environmental, and pharmaceutical samples using 4-[N,N-(diethyl)amino] benzaldehyde thiosemicarbazone(2010) Naik, P.P.; Karthikeyan, J.; Nityananda Shetty, A.N.4-[N,N-(Diethyl)amino] benzaldehyde thiosemicarbazone (DEABT) is proposed as an analytical reagent for the spectrophotometric determination of platinum(IV). The DEABT forms 1:2 yellow complex with Pt(IV), which is sparingly soluble in water and completely soluble in water-ethanol-DMF medium. The Pt(IV)-DEABT complex shows maximum absorbance at 405 nm. Beer's law is valid up to 7.80 ?g cm-3, and optimum concentration range for the determination of platinum(IV) is 0.48-7.02 ?g cm-3. The molar absorptivity and Sandell's sensitivity of the method are found to be 1.755 × 104 dm3 mol-1 cm-1 and 0.0012 ?g cm-2, respectively. The relative error and coefficient of variation (n=6) for the method does not exceed ±0.43% and 0.35%, respectively. Since the method tolerates a number of metal ions commonly associated with platinum, it can be employed for the determination of platinum in environmental samples, pharmaceutical samples, alloys, catalysts, and complexes. The method is rapid as the Pt(IV)-DEABT complex is soluble in water-ethanol-DMF medium and not requiring any time consuming extraction method for the complex. © 2010 Springer Science+Business Media B.V.Item Effective oxidation of alcohols by Iron(III)-Schiff base-triphenylphosphine complexes(2010) Rani, S.; Badekai Ramachandra, B.Iron(III)-Schiff base-triphenylphosphine complexes catalyze the oxidation of alcohols to their corresponding carbonyl compounds in presence of hydrogen peroxide in good yields. © 2010 Elsevier Ltd. All rights reserved.Item Synthesis, characterization and in vitro cytotoxic properties of some new Schiff and Mannich bases in Hep G2 cells(Birkhauser Boston, 2011) Dhanya, D.; Isloor, A.M.; Shetty, P.; Chandrakantha, B.; Satyamoorthy, K.A series of 5-substituted-4-amino-3-mercapto- 1,2,4-triazoles were synthesized and were treated with various 3-substituted pyrazole aldehydes to obtain a series of new Schiff bases (3a-l). Few of the selected Schiff bases were converted into Mannich bases by reaction with diphenylamine/morpholine in presence of formaldehyde in ethanol media (4a-e, 5a-e). These newly synthesized compounds were characterized by elemental analysis, IR, NMR and mass spectrometry studies. A comparative study on the cytotoxic activities of few selected Schiff and Mannich bases was done in HepG2 cells using MTT assay. Few of the screened Schiff bases, 3a, 3d, 3e, 3g and 3h showed dose dependent cytotoxic activity, 3a being the most potent with an IC50 value of 0.018 g/l comparable to the standard drug doxorubicin. Among the Mannich bases, 5b was the most active with an IC50 value of 0.034 g/l. The Schiff bases were found to be more active, when compared to Mannich bases derived from them. The morpholine derived Mannich bases were more potent than those obtained from diphenyl amine. © Springer Science+Business Media, LLC 2010.Item Performance and emission characteristics of double cylinder CI engine operated with cardanol bio fuel blends(2012) Mallikappa, D.N.; Reddy, R.P.; Murthy, C.S.N.India imports more than seventy percent of the oil it uses and is looking for alternative fuel to reduce its dependence on imports. In India, bio fuels derived from non-edible oils is considered as a renewable alternative to the fossil diesel. The cost of the biodiesel is higher than diesel and hence in this work, cardanol was used as an alternative renewable fuel for the diesel engine. The engine tests were conducted on a double cylinder, direct injection, compression ignition engine. From the engine tests, it is observed that the brake power increases (by 70% approximately) as load increases. Brake specific energy conversion decreases (by 25-30% approximately) with increase in brake power. Brake thermal efficiency increases with higher brake power and emission levels (HC, CO, NOX) were nominal up to 20% blends. © 2011 Elsevier Ltd.Item Palladium complex in a room temperature ionic liquid: A convenient recyclable reagent for catalytic oxidation(Taylor and Francis Ltd., 2014) Dileep, R.; Badekai Ramachandra, B.; Suresha Kumara, T.H.S.Palladium (Pd)-catalyzed carbonylation of alcohols proceeds in ionic liquid (IL) media (1-ethyl-3-methylimidazolium hexafluorophosphate). Carbonylation of primary/secondary alcohols to aldehydes/ketones was greatly accelerated by the use of a Pd-based catalyst in the presence of NaOCl as an oxidant. The catalyst was more easier to recycle in the IL [Emim]PF6 with an equal-proportioned CH2Cl2 than in the single CH2Cl2 or IL. © 2014 The Author(s). Published by Taylor & Francis.Item Extraction, characterization and biological studies of phytochemicals from Mammea suriga(Xi'an Jiaotong University, 2015) Poojary, M.M.; Vishnumurthy, K.A.; Vasudeva Adhikari, A.V.Abstract The present work involves extraction of phytochemicals from the root bark of a well-known Indian traditional medicinal plant, viz. Mammea suriga, with various solvents and evaluation of their in vitro antimicrobial and antioxidant activities using standard methods. The phytochemical analysis indicates the presence of some interesting secondary metabolites like flavonoids, cardiac glycosides, alkaloids, saponins and tannins in the extracts. Also, the solvent extracts displayed promising antimicrobial activity against Staphylococcus aureus, Bacillus subtilis and Cryptococcus neoformans with inhibition zone in a range of 20-33 mm. Further, results of their antioxidant screening revealed that aqueous extract (with IC50 values of 111.51±1.03 and 31.05±0.92 ?g/mL in total reducing power assay and DPHH radical scavenging assay, respectively) and ethanolic extract (with IC50 values of 128.00±1.01 and 33.25±0.89 ?g/mL in total reducing power assay and DPHH radical scavenging assay, respectively) were better antioxidants than standard ascorbic acid. Interestingly, FT-IR analysis of each extract established the presence of various biologically active functional groups in it. © 2015 Xi'an Jiaotong University.Item Anionic surfactant based reverse micellar extraction of l-asparaginase synthesized by Azotobacter vinelandii(Springer Verlag, 2017) Murugesan, S.; Iyyaswami, R.; Kumar, S.V.; Surendran, A.Abstract: l-Asparaginase synthesized by Azotobacter vinelandii via submerged fermentation in the presence of sucrose was successfully extracted using Reverse micellar extraction. Single step enzyme purification process was developed by varying the process variables which resulted in maximum specificity and extraction of l-asparaginase. The effect of different variables, including broth pH, addition of alcohol during the forward extraction and pH of the fresh stripping aqueous phase, addition of alcohol and electrolyte during backward extraction process were studied. Lower concentration of butanol resulted in maximum activity of the enzyme during forward extraction while enzyme activity was found to increase further with the addition of higher concentrations of ammonium sulphate during backward extraction. Chromatographic analysis of l-asparaginase peak at ~7.65 min was intense for the back extracted sample confirming the maximum purity of l-asparaginase obtained. Purity of l-asparaginase was increased to about 379.68 fold. Graphical abstract: [Figure not available: see fulltext.]. © 2017, Springer-Verlag Berlin Heidelberg.Item Enhancement of n-3 polyunsaturated fatty acid glycerides in Sardine oil by a bioimprinted cross-linked Candida rugosa lipase(Elsevier Inc. usjcs@elsevier.com, 2018) Sampath, C.; Belur, P.D.; Iyyaswami, R.Considering the advantages of bioimprinting and carrier free immobilization, cross-linked enzyme aggregates (CLEA) were prepared by using bioimprinted Candida rugosa lipase (CRL) with Bovine serum albumin (BSA), Polyethyleneimine and glutaraldehyde. Effect of various factors such as CRL-Oleic acid ratio, CRL-BSA ratio, CRL- Polyethyleneimine ratio, glutaraldehyde loading, cross-linking time etc., on lipase activity recovery and aggregate yield were studied and optimized. This immobilized lipase (CRL-CLEA) was used for the selective hydrolysis of ester linkages of non-PUFA glycerides, with an aim to concentrate EPA and DHA glycerides in the Sardine oil. Imprinting with oleic acid in the presence of ethanol and Tween 60, and further immobilization with co-aggregates and cross-linking agent showed 10.4 times higher degree of hydrolysis compared to free enzyme. As result, 2.83-fold increase of n-3 PUFA content in deacidified oil was obtained by using CRL-CLEA. The resultant oil had negligible di- and triglycerides content, proving higher efficiency in hydrolysing ester bonds of fatty acids, other than n-3 PUFA. Reusability studies showed CRL-CLEA could be reused up to 5 runs without a substantial reduction in its performance. Improvement in degree of hydrolysis, thermostability, efficiency of hydrolysis and reusability were achieved due to bioimprinting and subsequent immobilization of CRL in the form of CLEA. © 2017 Elsevier Inc.Item Effect of 1-pentanol addition and EGR on the combustion, performance and emission characteristic of a CRDI diesel engine(Elsevier Ltd, 2020) Radheshyam; Santhosh, K.; Kumar, G.N.Experimental study of 1-pentanol addition and EGR rates on the combustion, performance and emission of a CRDI diesel engine is carried out in this work. 1-Pentanol being a higher alcohol has fuel properties comparable to diesel. Experiments were conducted on a 4 stroke two cylinder, CRDI diesel engine running at a constant speed of 2000 rpm for lower load and higher load. Test fuels were prepared by blending the 1-pentanol with diesel, and tests were carried out for 5%, 10%, 20%, 30% and 40%, 1-pentanol blended in diesel on a volume basis. Effect of EGR rates of 10% and 20% were also studied. It had observed that engine can be run up to 30% of 1-pentanol blended fuel without any engine modification, but with raise in the percentage of 1-pentanol in the blends, BSFC increases and BTE decreases. Combustion characteristic for blended fuel depends upon the load. At higher load due to premixed combustion MGT, CP and NHR were almost same compared to the diesel. Reduction in NOx emissions was noted for all the fuel blends at the cost of HC and CO emission. 1-pentanol is a renewable biofuel, with use of 1-pentanol the dependency on petrodiesel can be overcome. © 2019 Elsevier Ltd