Selective synthesis of 6,8-di-<i>t</i>-butylated flavan over Zn–Al containing mesoporous silica catalysts

Selvaraj, M.,Sinha, P. K.,Park, D.-W.,Kim, Il,Kawi, S.,Ha, C. S. The Royal Society of Chemistry 2012 Dalton Transactions Vol.41 No.46

<P>We demonstrate a much green synthesis method for highly selective synthesis of 6,8-di-<I>t</I>-butylated flavan (6,8-DTBF) by liquid phase alkylation of 2,4-di-<I>t</I>-butylphenol (2,4-DTBP) with cinnamyl alcohol (Cin-OH) over mesoporous Zn–Al–MCM-41 catalysts synthesized under direct basic hydrothermal method. The main alkylated product, 6,8-DTBF is importantly used as an intermediate in the manufacture of biosynthetic organic compounds. The recyclable mesoporous Zn–Al–MCM-41 catalysts have also been reused in this reaction to study their catalytic activities. The influences of various reaction parameters such as temperature, time, ratios of reactant (2,4-DTBP-to-Cin-OH) have been extensively investigated for the synthesis of 6,8-DTBF. In addition, dimethyl sulfoxide (DMSO) has also been used as a solvent in this catalytic reaction. The mesoporous Zn–Al–MCM-41(75) gives excellent catalytic activity with 6,8-DTBF selectivity (86.0%) and 2,4-DTBP conversion (63.1%), and these catalytic results have also compared with that obtained using other mesoporous and microporous catalysts. On the basis of catalytic activity obtained by using the all catalysts, the Zn–Al–MCM-41(75) catalyst is found to be a highly active, recyclable and eco-friendly heterogeneous catalyst in the liquid-phase alkylation of 2,4-DTBP.</P> <P>Graphic Abstract</P><P>Zn–Al–MCM-41(75) catalyst is found to be a highly active, recyclable and eco-friendly green catalyst in the liquid-phase alkylation of 2,4-DTBP. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2dt31409f'> </P>

Highly active mesoporous chromium silicate catalysts in side-chain oxidation of alkylaromatics

Selvaraj, M.,Park, D.-W.,Kim, I.,Kawi, S.,Ha, C. S. The Royal Society of Chemistry 2012 Dalton Transactions Vol.41 No.46

<P>We approach a green method in the production of alkylaromatic ketones over hexagonally ordered mesoporous CrSBA-15 catalysts, which were used, in green routes, in the liquid-phase oxidation of alkylaromatics. A promising chemical treatment method was used with ammonium acetate solution to remove the toxic nature of non-framework chromium oxides deposited on the surface of calcined CrSBA-15(8), and the obtained green mesoporous CrSBA-15(8) catalyst was used to find its catalytic activity while the recyclability of mesoporous CrSBA-15 catalysts was also studied. Particularly, the mesoporous CrSBA-15 catalysts synthesized with a variety of chromium contents were extensively used in the production of acetophenone (AP&z.dbd;O) with various reaction parameters. On the basis of all catalytic results, the mesoporous CrSBA-15(8) catalyst produced a higher selectivity of alkylaromatic ketones (76–100%) as compared to other CrSBA-15 catalysts and was found to be a highly active, recyclable and promising heterogeneous catalyst for selective synthesis of alkylaromatic ketones.</P> <P>Graphic Abstract</P><P>Mesostructured green mesoporous CrSBA-15 catalyst has exceptional catalytic activity in oxidation of alkylaromatics. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2dt31571h'> </P>

Identification of Out-of-distribution (OOD) Signals in Fault Detection of Manufacturing Machines through both Supervised and Unsupervised Learning Techniques

S. Min(민상기),V. Selvaraj(셀바라지 빅네쉬),S.-H. Ahn(안성훈) Korean Society for Precision Engineering 2022 한국정밀공학회 학술발표대회 논문집 Vol.2022 No.10

Embargo Nature of CuO-PANI Composite Against Corrosion of Mild Steel in Low pH Medium

Selvaraj, P. Kamatchi,Sivakumar, S.,Selvaraj, S. The Korean Electrochemical Society 2019 Journal of electrochemical science and technology Vol.10 No.2

Incorporation of CuO nanoparticles during the polymerization of aniline in the presence of ammonium peroxydisulphate as an oxidizing agent and sodium salt of dodecylbenzene sulphonic acid as dopant as well as surfactant yielded water soluble CuO-PANI composite. Comparison of recorded spectra like FTIR, XRD and SEM with reported one confirm the formation of the composite. Analysis by gravimetric method exposes that the synthesized composite is having resistivity against corrosion, with slight variation in efficiency on extending the time duration up to eight hours in strong acidic condition. OCP measurement, potentiodynamic polarization and EIS studies also confirms the suppression ability of composite against corrosion. Riskless working environment could be provided by the synthesized composite during industrial cleaning process.

Selective synthesis of vitamin K₃ over mesoporous NbSBA-15 catalysts synthesized by an efficient hydrothermal method

Selvaraj, M.,Park, D.-W.,Kim, I.,Kawi, S.,Ha, C. S. The Royal Society of Chemistry 2012 Dalton Transactions Vol.41 No.32

<P>Well hexagonally ordered NbSBA-15 catalysts synthesized by an efficient hydrothermal method were used, for the first time, for the selective synthesis of vitamin K<SUB>3</SUB> by liquid-phase oxidation of 2-methyl-1-naphthol (2MN1-OH) under various reaction conditions. The recyclable NbSBA-15 catalysts were also reused to find their catalytic activities. To investigate the leaching of non-framework niobium species on the surface of silica networks, the results of original and recyclable NbSBA-15 catalysts were correlated and compared. To find an optimum condition for the selective synthesis of vitamin K<SUB>3</SUB>, the washed NbSBA-15(2.2pH) was extensively used in this reaction with various reaction parameters such as temperature, time and ratios of reactant (2M1N-OH to H<SUB>2</SUB>O<SUB>2</SUB>), and the obtained results were also demonstrated. Additionally, the liquid-phase oxidation of 2M1N-OH was carried out with different solvents to find the best solvent with a good catalytic activity. Based on the all catalytic studies, the vitamin K<SUB>3</SUB> selectivity (97.3%) is higher in NbSBA-15(2.2pH) than that of other NbSBA-15 catalysts, and the NbSBA-15(2.2pH) is found to be a highly active and eco-friendly heterogeneous catalyst for the selective synthesis of vitamin K<SUB>3</SUB>.</P> <P>Graphic Abstract</P><P>Mesostructured NbSBA-15 catalysts were used, in novel green routes, for the synthesis of vitamin K<SUB>3</SUB> from 2-methyl-1-naphthol. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2dt31096a'> </P>

Enhancement of methanol production from synthetic gas mixture by Methylosinus sporium through covalent immobilization

Patel, S.K.S.,Selvaraj, C.,Mardina, P.,Jeong, J.H.,Kalia, V.C.,Kang, Y.C.,Lee, J.K. Applied Science Publishers 2016 APPLIED ENERGY Vol.171 No.-

<P>Both methane (CH4) and carbon dioxide (CO2) are major greenhouse gases (GHGs); hence, effective processes are required for their conversion into useful products. CH4 is used by a few groups of methanotrophs to produce methanol. However, to achieve economical and sustainable CH4 reduction strategies, additional strains are needed that can exploit natural CH4 feed stocks. In this study, we evaluated methanol production by Methylosinus sporium from CH4 and synthetic gas. The optimum pH, temperature, incubation period, substrate, reaction volume to headspace ratio, and phosphate buffer concentration were determined to be 6.8, 30 C, 24 h, 50% CH4, 1:5, and 100 mM (with 20 mM MgC12 [a methanol dehydrogenase inhibitor]), respectively. Optimization of the production conditions and process parameters significantly improved methanol production from 0.86 mM to 5.80 mM. Covalent immobilization of M. sporium on Chitosan significantly improved the stability and reusability for up to 6 cycles of reuse under batch culture conditions. The immobilized cells utilized a synthetic gas mixture containing CH4, CO2, and hydrogen (at a ratio of 6:3:1) more efficiently than free cells, with a maximum methanol production of 6.12 mM. This is the first report of high methanol production by M. sporium covalently immobilized on a solid support from a synthetic gas mixture. Utilization of cost-effective feedstocks derived from natural resources will be an economical and environmentally friendly way to reduce the harmful effects of GHGs. (C) 2016 Elsevier Ltd. All rights reserved.</P>

Phototrophic Bacteria as Fish Feed Supplement

Banerjee, S.,Azad, S.A.,Vikineswary, S.,Selvaraj, O.S.,Mukherjee, T.K. Asian Australasian Association of Animal Productio 2000 Animal Bioscience Vol.13 No.7

Single cell of an indigenous phototrophic bacterium, Rhodovulum sulfidophilum, was incorporated in commercial fish feed for Oreochromis niloticus. The bacterial cell was analyzed for nutritional value and tested for toxicity and acceptability as an aquaculture feed supplement. The results showed higher survival rate and significantly higher growth rate (p<0.001) in O. niloticus fed with the bacteria incorporated fish feed. It is suggested that R sulfidophilum can be utilized as an aquaculture feed supplement.

Phytoremediation of metal-contaminated soils by the hyperaccumulator canola (Brassica napus L.) and the use of its biomass for ethanol production

Dhiman, S.S.,Selvaraj, C.,Li, J.,Singh, R.,Zhao, X.,Kim, D.,Kim, J.Y.,Kang, Y.C.,Lee, J.K. Butterworths [etc.] ; Elsevier Science Ltd 2016 Fuel Vol.183 No.-

This study evaluates the phytoremediation potential of canola biomass, which was grown on soils contaminated by several metals. The increase in metal concentration was measured in different parts of the growing biomass. Nearly 95mg zinc/kg soil of the zinc supplied to the soil accumulated within the roots of canola. To test the suitability of the canola biomass for bioethanol production, a saccharification was performed after phytoextraction of metals. Armillaria gemina and Pholiota adiposa were co-cultured to obtain a highly active lignocellulase cocktail. Saccharification yields (SY) of 71.8% and 74.4% were obtained with biomass contaminated with nickel and copper, respectively. Under similar conditions, Celluclast® 1.5L in combination with commercial β-glucosidase resulted in a SY of 73.4%. Fermentation using the hydrolysate of canola biomass used in the phytoremediation yielded 68.9% of bioethanol. To our knowledge, this is the first study where canola biomass used for phytoremediation was tested for bioethanol production through saccharification.

Photocatalytic oxidation of ceftiofur sodium under UV–visible irradiation using plasmonic porous Ag-TiO2 nanospheres

N. Pugazhenthiran,S. Murugesan,H. Valdés,M. Selvaraj,P. Sathishkumar,P.G. Smirniotis,S. Anandan,R.V. Mangalaraja 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.105 No.-

In this study, 250 nm sized porous anatase TiO2 nanospheres (TiO2 NSPs) composed of 10 nm sized anataseTiO2 nanoparticles are obtained through a green synthetic route and their surfaces have been decoratedwith 3–4 nm sized plasmonic silver nanoparticles (AgNPs). Photoluminescence studies confirm thatthe AgNPs presence on TiO2 NSPs surface effectively inhibits the radiative charge recombination and thusfacilitates charge separation process at the Ag-TiO2 NSPs interface, causing an enhanced photocatalyticactivity. About 92% of the ceftiofur sodium (CFS) antibiotic taken initially is oxidized by Ag-TiO2 NSPsupon 90 min white light irradiation, while Ag loaded Degussa P25 TiO2 nanoparticles effects only 71%CFS oxidation. The synergistic effect given by plasmonic AgNPs and the continuous framework of anataseTiO2 NPs contributes to inhibit the electron-hole recombination in the Ag-TiO2 NSPs. Oxidation productsof CFS in different water sources and their eco-toxicity effects identified through LC-MS and microtoxbioassays,respectively, indicate that the obtained oxidation products are non-toxic compared to pureCFS. Therefore, porous Ag-TiO2 NSPs could be successfully applied in photocatalytic oxidation technologies,exploiting sunlight for the effective removal of pharmaceutical pollutants from wastewater.

Vibration control of structural systems via robust non-fragile sampled-data control scheme

Sakthivel, R.,Aravindh, D.,Selvaraj, P.,Kumar, S.V.,Anthoni, S.M. Pergamon 2017 Journal of the Franklin Institute Vol. No.

<P>This paper investigates the dissipative non-fragile output feedback sampled-data control problem for uncertain structural systems. In the proposed system, uncertainties are assumed to be time-varying and bounded, which are considered in the linear fractional transformation form. The main objective of this paper is to design a non-fragile sampled-data controller such that the resulting closed-loop system is strictly (Q,S,R)-alpha-dissipative. On the basis of a suitable Lyapunov Krasovskii functional and linear matrix inequality technique, a new set of sufficient conditions is established to achieve the required result for both nominal and uncertain systems. In particular, an output feedback dissipative sampled-data controller is designed by solving a set of matrix inequalities. More precisely, Schur complement lemma, free weighting matrix approach and Wirtinger-based double integral inequality are utilized to substantially simplify the derivation of the main results. Finally, simulations based on structural systems are conducted to illustrate the effectiveness of the proposed control scheme. (C) 2016 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.</P>