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Subrahmanya Bhat K

Subrahmanya Bhat K
Manipal Institute Of Technology, Manipal Academy of Higher Education-576104

MSc, PhD

About

66
Publications
26,002
Reads
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2,329
Citations
Citations since 2016
39 Research Items
1791 Citations
20162017201820192020202120220100200300400
20162017201820192020202120220100200300400
20162017201820192020202120220100200300400
20162017201820192020202120220100200300400
Introduction
Presently work as an Associate Professor in the Department of Chemistry, Manipal Institute of Technology, Manipal Academy of Higher Education Manipal, India. Worked at prestigious GE-India and where received Patent Award, qualified in NET for lectureship of CSIR, and received the Citation Award from Elsevier. Has over 70 research publications and 2 patents. Note: Requests for collaborations may be sent by e-mail for review and decision.
Additional affiliations
May 2001 - December 2004
Mangalore university
Position
  • Synthesis and.......

Publications

Publications (66)
Article
Full-text available
Two benzonitrile derivatives, namely 4-(isopentylamino)-3-nitrobenzonitrile (PANB) and 3-amino-4-(isopentylamino)benzonitrile(APAB) have been synthesized and evaluated as corrosion inhibitors for mild steel (MS) in 1 M HCl solution at 303 K by gravimetric, potentiodynamic polarization (PDP) curves, and electrochemical impedance spectroscopy (EIS) m...
Article
Full-text available
Various experimental and theoretical methods have been employed to study the effectiveness of two pyrazoline derivatives namely, 2-(4-(5-(p-tolyl)-4,5- dihydro-1H-pyrazol-3-yl)phenoxy)acetic acid (P1) and 2-(4-(5-(4-nitrophenyl)-4,5- dihydro-1H-pyrazol-3-yl)phenoxy)acetic acid (P2) as corrosion inhibitors for mild steel in 1.0 M HCl at 303 K. The i...
Article
Full-text available
The study of polymer matrix composites had become an important topic for academic and and industrial reasearch. The current thrust for materials which are environmental friendly and biodegradable made researchers to focus on alternate options to synthetic materials. One major area of research in this direction is in the area composites of polymers...
Article
The effect of three chalcone derivatives namely, (E)-ethyl 2-(4-(3-(4-fluorophenyl)acryloyl)phenoxy)acetate (AE-1), (E)-ethyl 2-(4-(3-(3,4-dichlorophenyl)acryloyl)phenoxy)acetate (AE-2) and (E)-ethyl 2-(4-(3-(2,5-dimethoxyphenyl)acryloyl)phenoxy)acetate (AE-3) on the mild steel (MS) corrosion in 1.0 M HCl at 303 K has been investigated using experi...
Article
Full-text available
Good quality single crystals of an efficient nonlinear optical (NLO) chalcone derivative 1-(5-chlorothiophen-2-yl)-3-(2,3-dichlorophenyl)prop-2-en-1-one (CTDCP) which meets many of the physicochemical requirements like transparency in the entire visible region, thermal stability, mechanical hardness have been achieved. The crystal belongs to orthor...
Article
The present paper reports effect of chemical modification of bagasse fibers by using oxidizing agents like potassium permanganate and potassium dichromate. The fiber modification was assessed by several techniques like Fourier Transfer Infrared Spectroscopy (FTIR), Thermo Gravimetric Analysis (TGA), and X-Ray Diffraction (XRD) which provide evidenc...
Article
Full-text available
The scenario of the Automobile Industry has changed, not only in India but also for the world as a whole. Rise in demand for more sustainable mobility and vehicles with increased usage of renewable energies have given rise to a revolution. This revolution has not only been affecting mankind for better implementation of resources but has also shown...
Article
Chalcone derivatives are known for their characteristic non-linear optical efficiency. In the present work, the relation between the molecular structure and non-linear optical properties of a synthesized chalcone derivative 4-[(1E)-3-(5-chlorothiophen-2-yl)-3-oxoprop-1-en-1-yl] phenyl4-methylbenzene-1-sulfonate (4TPMS) have been investigated by com...
Conference Paper
An organic nonlinear optical material which possesses third order nonlinearity has been grown by slow solvent evaporation technique at room temperature. The structural, linear optical and nonlinear optical properties of 4-[(1E)-3-(4-chlorophenyl)-3-oxoprop-1-en-1-yl]phenyl-4-methyl-benzene-1-sulfonate (4CPMS) have been studied. The 1H-NMR study was...
Article
Full-text available
Natural fiber composites expected to be in great demand in the coming years due to increased consumer awareness to reduce the waste and environmental pollution. Bagasse fibers available in plenty as an agro-residue and bio composites derived from such renewable resources offer potential for scale-up and value addition. This review provides an insig...
Article
Water pollution by dyes from industries is a serious environmental problem. The toxicity of dyes constitutes a great risk to the environment and human health. Due to the simplicity and cost-effectiveness of the remediation process, adsorption has been widely accepted in wastewater treatment. Recent advances in nanotechnology offer considerable adva...
Article
Full-text available
Developing environmentally friendly products is a modern science and an important task for today's chemistry and technology scholars. In the present research work, two new green chemical compounds, namely 1-benzoyl-6,6 dimethyl-2-phenyl-5,7 dioxaspiro[2.5]octane-4,8 dione (BMP) and 1-benzoyl-6,6-dimethyl-2-(4-nitrophenyl)-5,7-dioxaspiro[2.5]octane-...
Article
Full-text available
Controlling corrosion of metals such as mild steel (MS), which is extensively employed in various industrial fields, is a topic of great interest for researchers and scientists. At the same time, designing highly effective and environmentally friendly corrosion inhibitors is most desired yet still challenging. In this context, this study focuses on...
Chapter
Full-text available
Fiber-reinforced nanocomposites can be prepared in two ways: (1) by using nanofibers to reinforce nanocomposite and (2) by incorporating nanomaterials into fiber-reinforced composites. Recently the multiscale (hierarchical) fiber-reinforced nanocomposites have been developed by using two different reinforcements: fibers (at the microscale) and nano...
Article
The present work deals with the influence of wood dust namely Rosewood and Padauk in the jute fiber-based epoxy composites. The work involves the fabrication of four different laminates of jute-epoxy composites using hand layup process with varying proportions of Rosewood and Padauk wood dust fillers compared with the composite in the absence of fi...
Article
The development of cost-effective, sustainable, eco-friendly and efficient compounds is a renovated science and a demanding assignment for today’s chemists and technology specialists. In this context, the anticorrosion effect of a new Schiff base hydrazone, namely (E)-2-(4-(2-(methyl(pyridin-2-yl)amino)ethoxy)benzylidiene)hydrazine-1-carboxamide (M...
Article
Full-text available
Bagasse fiber which is abundantly available as waste after processing of sugarcane is used as reinforcement with an epoxy polymer in forming the natural fiber reinforced composites. The raw fibers were treated chemically to improve compatibility and adhesion with the epoxy polymer. Treated and untreated fibers were subjected to analysis such as Sca...
Article
Full-text available
Material corrosion is one of the outstanding challenging problems in the industry, and it strongly influences refining and petrochemical plants lifetime. Therefore, prevention of the corrosion of different metals and alloys is imperative in the viewpoint of industrial safety and productivity. For this purpose, the application of suitable corrosion...
Article
The use of green and environmentally friendly substances is a contemporary scientific challenge and a key task for today's specialists in chemistry and technology-related fields. In this context, this research work involves the study of two new compounds named 1-benzoyl-2-(3,4-dimethoxyphenyl)-6,6-dimethyl-5,7-dioxaspiro [2.5]octane-4,8-dione (2-MP...
Article
Full-text available
High performance natural cellulosic fiber can contribute to fiber-reinforced polymer composites or as organic fillers through replacement of the synthetic or man-made fibers. The natural fibers extracted from various parts of plant sources provides healthy and sustainable environment. Hence, the present work aimed to identify agro-residues of Cajan...
Article
Iron and its alloys are commonly used materials in petroleum refining facilities. However, poor corrosion resistance is always a disturbing problem for these industries. Herein, we demonstrated the utility of two pyrazoline derivatives (PYRs), namely, 2-(4-(4,5-dihydro-3-(4-methoxyphenyl)-1H-pyrazol-5-yl)phenoxy)acetic acid (PYR-1) and 2-(4-(4,5-di...
Conference Paper
Full-text available
This review summarizes the ongoing research activities on morphological changes being brought about by subjecting the natural cellulosic fibers to various chemical treatments. Most of the natural fibers being used as reinforcements in poly meric resins to form the polymer matrix composites are considered. The natural fibers contain an abundant numb...
Article
Agro-industrial by-products are an alternative potential source to replace synthetic fibers /filler materials. Pistachio (Pistacia vera) nut processing industries producing Pistacia vera nutshell (PVNS) as waste in large quantity. The nutshells are characterized for the first time towards their Physicochemical properties like particle size, structu...
Article
Full-text available
Phoenix pusilla fibres (PPFs) were extracted from the leaves of a plant belonging to thefamily of Arecaceae, which is widely grown in Sri Lanka and Southern parts of India forsome medicinal purposes. Their use as possible reinforcement in hydrophobic polymericmatrix composites is yet to be studied and for this reason, the better understanding ofthe...
Article
Full-text available
The present study aimed to evaluate the inhibition effect of an organic compound, namely, (E)-N'-(2-hydroxybenzylidene)isonicotinohydrazide (BIH), for carbon steel corrosion in a 1.0 M HCl solution, by using weight loss (WL), potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). Results show that BIH is a good inhibit...
Article
Full-text available
A novel quinazoline derivative, 3-cyclopropyl-3,4-dihydroquinoline-2(1H)-One (CPHQ), was successfully designed and synthesized. Then, its corrosion inhibition behavior on carbon steel (CS) surface in 1.0 M HCl at different temperatures was investigated using chemical, electrochemical and theoretical techniques. The experiments confirmed that the st...
Article
Full-text available
Organic material (chalcone derivative 4-[(1E)-3-(4-methoxyphenyl)-3-oxoprop-1-en-1-yl]phenyl 4-methylben-zene-1-sulfonate {4MPMS}) has been grown by solvent evaporation technique. The structural properties have been carried out by powder XRD and single crystal XRD data. The linear optical properties (band gap, extinction coefficient , optical condu...
Article
Full-text available
The present investigation aimed to understand the physico-chemical properties of new natural fiber extracted from Albiziaamara bark. The chemical composition, structural, thermal and tensile properties of Albiziaamara fibers (AAFs) were investigated. The results indicated that AAF had crystallinity index of (63.78 %), cellulose (64.54 wt. %), hemic...
Article
The corrosion inhibition properties of three quinoline derivatives namely, 2,6-dichloroquinoline-3-carbaldehyde (QA-1), 2-chloro-6-nitroquinoline-3-carbaldehyde (QA-2) and 2,6-dichloro-8-nitroquinoline-3-carbaldehyde (QA-3) for mild steel (MS) in 1.0 M HCl at 303 K were studied by using electrochemical techniques, the density functional theory and...
Article
There is a need for academicians and researchers to publish the work they do. It preserves the scholarly record for the use of future generations, and many a time, can save the time and energy of others from working on the same topic or sometimes, will help others to improve on the existing ideas. While enhancing scienti c knowledge by documentatio...
Article
The crystal structure of the title compound has been determined from X-ray diffraction studies. The compound crystallizes from methanol in the monoclinic system with space group P21/c with unit cell parameters: a= 10.647 (8), b=8.494 (6), c=16.743 (12) Å, β=92.731 (13)°, Z=4, V=1512.4(19)ų. The structure was determined by direct methods and refine...
Article
Full-text available
Natural fibre reinforced polyester composites were prepared using bast fibres as the reinforcement which were extracted from Grewia serrulata trees. Chemical treatments such as alkali pretreatment followed by permanganate treatment, acetylation and silane treatment were exclusively applied to modify the fibre surface. Hand lay-up technique with com...
Article
Full-text available
A series of pyrazoline derivatives with tosyloxy substitution were synthesized and characterized. They were evaluated for antimicrobial potential against Mycobacterium smegmatis, gram positive Staphylococcus aureus, gram negative Escherichia coli, and a fungi Candida albicans. The initial screening using zones of inhibition at 50µL concentrations r...
Article
Partially bio-degradable composites were prepared using bast fibres extracted from Grewia Serrulata trees with unsaturated polyester resin. Different durations of fibre pre treatment and volume fraction variations were tried for fabricating the composites. Hand lay-up technique was used for the fabrication; tensile strength and flexural strength of...
Article
Full-text available
Substitution of tosyl group on hydroxyacetophenones orhydroxybenzaldehyde and their subsequent condensation yielded several tosyloxy substituted chalcones which were derivatized to obtain the correspondingpyrimidinethione derivatives. The synthesized compounds were characterized by spectroscopic techniques like FT-IR, 1H NMR, 13C NMR, and mass spec...
Article
Full-text available
Infectious diseases are on the rise due to development of multidrug resistant strains, and this renders the search for newer antimicrobials. Hybrid compounds of different scaffolds, are expected to enhance the bioactivity by improved affinity to target proteins while retaining the biological efficacy of each of the components. In view of this a ser...
Article
Full-text available
4-Tosyloxychalcone derivative, C23H20O4S, was synthesized and characterized by infrared and 1H NMR spectral studies. Grown crystal was further characterized by single crystal X-ray diffraction studies. The compound crystallizes in monoclinic space group C2/c with unit cell parameters a = 33.431 (6) Å, b = 5.8451 (10) Å, c = 21.439 (4) Å, Z = 8 and...
Article
Full-text available
Reaction of active methylene compound with an aldehyde and thiourea under Biginelli conditions reported to yield dihydropyrimidine derivatives in good yield. Herein we report a special case wherein the isolated product was propanenitrile derivative resulting from Knoevenagel condensation of malononitrile with the aldehyde. The structure of the prod...
Article
Full-text available
We synthesized and studied the efficacy of hydroxy and corresponding tosyloxy chalcone derivatives to inhibit the growth of MDR strains of bacteria. The required compounds were synthesized using literature methods and characterized by spectroscopic techniques. Bacterial strains were isolated by clinical methods. Our studies show hydroxy chalcone de...
Article
Full-text available
A novel organic non-linear optical (NLO) compound (2E)-3-(2-methylphenyl)-1-(4-nitrophenyl) prop-2-en-1-one (2MPNP) has been synthesized and grown as a high-quality single crystal by the slow evaporation technique. 2MPNP crystals were characterized by FT-IR, UV-Vis-NIR, NMR, DSC and Single Crystal XRD techniques. 2MPNP crystallizes in the orthorhom...
Conference Paper
Full-text available
Partially bio-degradable composites were prepared using fibres extracted from Grewia Serrulata plant with unsaturated polyester resin. Fibres were cut into lengths of 10 mm and 20 mm and were subjected to alkali pre-treatment. The hand lay-up technique was used for the fabrication of the composites. Tensile strength and flexural strength of the spe...
Article
Full-text available
A chalcone derivative, 1-(5-bromothiophen-2-yl)-3-(2,3-dimethoxyphenyl)prop-2-en-1-one (BTDMP), has been synthesized and grown as a high-quality single crystal by the slow evaporation solution growth technique. The compound was characterized by FT-IR and NMR studies. The crystal has been subjected to single-crystal X-ray diffraction studies and cel...
Conference Paper
Full-text available
Polymer additives for applications as FR additive is in great demand. This paper demonstrates how 6 membered N-heterocycles can be efficiently used as polymeric additives to improve the fire behavior of plastics. The study includes the synthesis of a series of pyrimidinethione derivatives using conventional methods, which were characterized by spec...
Article
Full-text available
A potential crystal for nonlinear optical application and monomer namely 1-(2,4-dichloro-phenyl-2yl)-3-(4-hydroxyphenyl)prop-2-en-1-one (DHPP) was synthesized and grown by slow evaporation technique. The functional groups present in the compound were identified by FTIR spectrum. The optical cut-off wavelength and structural characteristics were ana...
Article
Full-text available
The derivatives of 4-hydroxychalcones were synthesized and characterized by infrared and 1 H NMR spectral studies. The grown crystal was further characterized by single crystal x-ray diffraction studies. The crystal structure of (2E)-3-(4-hydroxyphenyl)-1-phenylprop-2-en-1-one was determined using single crystal x-ray diffraction. The compound crys...
Article
A new potentially useful nonlinear optical organic material, 1-(5-chlorothiophen-2-yl)-3-(2,3-dimethoxyphenyl)prop-2-en-1-one, has been synthesized and grown as a high-quality single crystal by the slow evaporation technique. The grown crystals were characterized by FT-IR, NMR, thermal analysis, and UV–visible spectroscopy. The material is thermall...
Article
A new potentially useful nonlinear optical (NLO) organic material, 1-(5-bromothiophen-2-yl)-3-(4-nitrophenyl)prop-2-en-1-one (BTNP), has been synthesized and grown as a high-quality single crystal by the slow evaporation technique. The grown crystals were chemically characterized by FT-IR and NMR studies. The grown crystal has been subjected to sin...
Article
Full-text available
Single crystals of 1-(5-chlorothiophen-2-yl)-3-(2,4,5-trimethoxyphenyl)prop-2-en-1-one (CTTMP) having nonlinear optical property have been grown by slow evaporation technique.The functional groups were identified by FT-IR and NMR techniques. The mechanical property of the crystals was studied using Vicker’s microhardness tester and the load depende...
Article
Full-text available
An efficient and new green synthetic protocol has been developed for the synthesis of bisphenol derivative containing sulphonyl group as pendent unit. This method uses solid p-toluene sulphonic acid and avoids the use of HCl gas or H 2SO 4 which are corrosive in nature and can be implemented in large scale for industrial applications.
Article
A series of 3-(2,4-dichloro-5-fluorophenyl)-6-(substituted phenyl)-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazines (4) (Fig. 1) have been synthesized by the cyclization of 3-(2,4-dichloro-5-fluorophenyl)-1,2,4-triazol-5-thiol (3) with substituted phenacyl bromides. All the newly synthesized compounds were confirmed by IR, (1)H NMR and mass spectral studie...
Patent
Full-text available
A polymer comprising structural units derived from a poly cyclic dihydroxy compound of Formula (I) Wherein R1, R2 and R3 are independently at each occurrence selected from the group consisting of a cyano functionality, a halogen, an aliphatic functionality having 1 to 10 carbons, a cycloaliphatic functionality having 3 to 10 carbons, and an aromati...
Patent
Full-text available
A process of forming a polycyclic dihydroxy compound is described. The polycyclic dihydroxy compound has For mula (I) Wherein R1, R2 and R3 are independently at each occurrence selected from the group consisting of a cyano functionality, a halogen, an aliphatic functionality having 1 to 10 carbons, a cycloaliphatic functionality having 3 to 10 carb...
Article
Full-text available
A series of 2,4-dichloro-5-fluorophenyl bearing Mannich base (4 and 5) was prepared from triazole Schiff bases (3) by aminomethylation with formaldehyde and secondary/substituted primary amines. All newly synthesized compounds were screened for their antimicrobial activity. Compounds 3c, 4c, 4e and 4f exhibited promising antibacterial and compounds...
Article
A series of 3-substituted-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazol-6-yl-2-(2,4-dichloro-5-fluorophenyl)quinolines 5 have been synthesized by the condensation of hitherto unreported quinoline-4-carboxylic acids 3 with various 3-substituted-4-amino-5-mercapto-1,2,4-triazoles 4. The structures of newly synthesized compounds have been confirmed on the ba...
Article
2-Chloro-1,4-phenylenedioxy-bis-acetyl hydrazine 1 on reacting with aromatic carboxylic acids in the presence of phosphorus oxychloride affords 2-chloro-bis-1,3,4-oxadiazoles 3a-f and 4a-d. Aroyl hydrazine 1 on reacting with carbon disulphide under basic condition gives oxadiazole-2-thione 2. Three out of four tested compounds show anticancer activ...
Article
Full-text available
The synthesis of a number of 1,3,4-oxadiazole derivatives have been described. 2,4-Dichloro-5-fluorobenzoyl hydrazine 1 on reacting with aromatic acids in presence of phosphorus oxychloride affords 2,5-disubstituted- 1,3,4-oxadiazoles 2a-j. Aroyl hydrazine on reacting with carbon disulphide under basic condition gives oxadiazol-2-thione 3. Oxadiazo...
Article
Full-text available
3-Substituted-4-amino-5-mercapto-1,2,4-triazoles are versatile synthons for constructing various biologically active heterocycles. Their cyclization with carboxylic acids gives fused five-membered derivatives, whereas with α-bromoketones gives a six-membered heterocycle. In this article we report the synthesis of a series of 1,2,4-triazolo[3,4-b]th...
Article
Full-text available
1,2,4-Triazolo[3,4-b]thiazole derivatives 5a–j have been synthesized by novel multi-component reaction of 2,4-dichloro-5-fluorophenacyl bromide (1), thiosemicarbazide (2), and aromatic carboxylic acids (4) using phosphorous oxychloride as the cyclizing agent. This reaction protocol is simple, efficient, and requires shorter reaction times in compar...
Article
In view of the pharmacological activities of 1,2,4-triazinones, a series of 4-amino-6-arylfuranylmethyl-3-mercapto-1,2,4-triazin-5(4H)-ones 7 have been synthesized by refluxing pyruvic acids 5 in ethanol with thiocarbohydrazide 6 on a steam-bath. The structures of 7 are confirmed by elemental analysis, IR, NMR and mass spectral data. Also, these co...
Article
A new method for the synthesis of furan-2-carboxaldehyde and 5-(substituted-phenyl)-furan-2-carboxylic acids using ceric ammonium nitrate (CAN) is reported.
Article
Full-text available
2,4-dichloro-5-fluorophenyl, 4-fluoro-3-(Phenoxy)phenyl, 4-fluorophen-yl groups are known pharmacophores and can be used in the synthesis of new biologically active molecules. Therefore, 4-amino-6-arylmethyl-3-mercapto-1,2,4-triazin5(4H)-ones 1 are condensed with 3-phenoxy-4-fluoro-benzoic acid, 2,4-dichloro-5-fluorobenzoic acid, and 4-fluorobenzoi...

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Projects (3)
Project
To achieve maximum strength for specific applications.
Project
DFT, Monte Carlo and Molecular dynamic simulations for investigation of adsorption behavior and inhibition mechanism of chemical compounds on the metallic surface in absence and presence of corrosive species like (Water, H3O+, Cl- ).