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Synthesis, Characterization and Analytical Applications of Disubstituted urea/thiourea derivatives
Two Urea/Thiourea derivatives have been synthesized in good yields from Urea/Thiourea and aniline in dry media conditions by using p-TSA as catalyst under microwave assisted method and they are characterized by IR and NMR spectral analysis. There are several advantages of foresaid catalyst like rate enhancements, higher yields, easy work-up procedure and energy efficient. The reaction has been done under solvent free condition having short reaction time period, increased safety and economic advantages. This Thiourea derivatives reagent has been used for the spectrophotometric determination of palladium. The results obtained by the proposed method is accurate reproducible. The proposed method has been successfully applied for the determination of palladium(II) in some synthetic mixtures of alloy samples and mineral. This dissertation contain five chapters Chapter 1 includes significance of Urea/Thiourea derivatives, green experimental protocol, heterogeneous catalysts. It also includes Objective of the study which is a develop a new methodology for the synthesis of Urea/Thiourea derivatives. Chapter 2 includes review of literature on the synthesis of Urea/Thiourea derivatives by different varieties of techniques. Different catalysts are used for that technique. Chapter 3 describes about materials and experimental procedures which are used in this synthesis . Chapter 4 deals with the various characterization results of Urea/Thiourea derivatives. It also describes the application of N,N??-diphenylthiourea in the trace level determination of palladium. Chapter 5 gives the summary and conclusion of the present study. It also gives the future scope of the present work. Furthermore, short reaction times, good yields of products, mild reaction conditions, and easy work-up/purification are the other noteworthy advantages which make this method a valid contribution to the existing methodologies is given in this chapter. Key works: Urea/Thiourea derivatives, p-TSA, MWI, IR, NMR, and Palladium. -
Synthesis, Characterization and Catalytic activity of Zirconia-Ceria catalysts
The development of catalysts is critical for the economical and environmentally efficient generation of chemical compounds that underlie every aspect of our society. Catalysts are key players in research involving the discovery of pharmaceuticals, materials, and polymers. In addition, catalysis is especially powerful in bulk synthesis, allowing the production of compounds, polymers and commodity chemicals via routes that would otherwise be impossible. Ceria is the unique rare earth for which dioxide is the normal stable phase contrary to the others for which Ln2O3 is the normal stoichiometry. The applications of ceria based materials are related to a potential redox chemistry involving Ce(III) and Ce(IV), high affinity of the element for oxygen and sulphur and absorption/excitation energy bands associated with its electronic structure. Zirconium is one of the more abundant elements, and is widely distributed in the Earth's crust. Being very reactive chemically, it is found only in the combined state or as part of a complex of oxides as in zircon, elpidite, and eudialyte. Doping ceria with zirconia may improve the oxygen storage properties of ceria at three different levels. At the level of the microstructure, it inhibits surface diffusion and in turn the loss of surface area at high temperatures. At the microscopic level, substantial doping may result in the formation of an interface structure that facilitates the oxygen transport from bulk to the surface. At the atomic-level, it stabilizes the oxygen defective structure. The texture, structure and thermal stability of ceria-zirconia doped oxides are closely related to the ratio of cerium to zirconium in the solid solution. Chapter 1 comprises of the general introduction of catalysis, importance of solid acid catalysis, sulphated metal oxides, pure ceria, pure zirconia, modified ceria and zirconia. It gives a brief introduction about the nitration of toluene. The aim and objectives of the present investigation are also described at the end of this chapter. Chapter 2 comprises of a thorough literature survey on the significance of solid acid and super acid catalysts in various domains of chemical industry and importance of anion promoted zirconia and ceria catalysts. The definition of ??super acid and their classification vii on the basis of origin of the active sites are also outlined. Importance of modified metal oxides is also outlined. Chapter 3 deals with the experimental procedures and techniques employed in this investigation. Scientific aspects of the precipitation and impregnation methods were outlined. The experimental details of surface area measurements by BET method, application of X-ray powder diffraction studies for crystalline phase and size determination, elemental detection by EDAX, spectral details from FTIR and thermal stability by TGA have been described. Chapter 4 deals with the various characterization results and discussion of pure, doped and sulphated Zirconia-ceria solid acid catalysts. The bulk and surface properties of the catalyst was discussed by XRD, BET surface area, TGA and FTIR. All characterization results revealed that the incorporated sulphate ions has a significant influence on the surface and bulk properties of the ZrO2-CeO2 catalyst. The prepared catalysts are investigated for the liquid phase nitration of toluene under various reaction conditions. Chapter 5 gives with the summary and conclusion of the present study. It also gives the future scope of the present study. On the whole, zirconia-ceria solid acid catalysts were successfully synthesized by simple route. Physicochemical characterization of all these catalysts revealed that the loaded sulphated and doped metal oxides show a significant influence on the surface and bulk properties of the ZrO2 - CeO2. These catalysts are found to be active for the liquid phase nitration of toluene. Key words: Solid acid catalysis, Zirconia-Ceria, Sulphated zirconia-ceria, Nitration of toluene -
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Synthesis, Adsorptive Properties and Applications of Modified Aluminum Oxyhydroxide-PVA Films
Over the past few years, there has been an increasing interest in polymer films and newlinemetal-incorporated polymer films because of their distinctive characteristics and newlinepotential applications. The effectiveness of alumina or modified alumina polymer films newlineas adsorbents or catalysts is greatly influenced by their surface properties, texture, chemical composition, and thermal stability. This thesis describes the synthesis of aluminum oxyhydroxide - polyvinyl alcohol composite films by sol-gel method. The synthesized films were modified by incorporating transition metals and cross-linking agents depending on the desired application as a catalyst or adsorbent. The synthesized films were characterized using different techniques, like powder X-ray diffraction studies (pXRD), Fourier transform infrared spectra (FTIR), Raman spectra, BrunauerEmmett-Teller surface area (BET), Barrett-Joyner-Halenda (BJH) isotherm, atomic newlineforce microscopy, optical profilometry, thermogravimetric analysis, Scanning electron newlinemicroscopy (S.E.M), and X-ray photoelectron spectroscopy (XPS) to determine the newlinestructural and textural properties. The films were deployed as adsorbents for the removal of heavy metals and dyes from water as well as catalysts for industrially important organic transformations. The results of the characterization studies were used to correlate the surface characteristics and adsorptive capacities of the fabricated films. The films were found to have tuneable surface properties and enhanced adsorptive newlinebehaviour, which could be modified as per the application. Transition metalincorporated films exhibited remarkable adsorption properties for the elimination of heavy metals and organic dyes from aqueous solution. The adsorption reaction kinetics newlinewere investigated to ascertain the rate and mechanism of the reaction to improve the newlineefficiency, economic efficiency and environmental sustainability of the reaction. -
Synthesis spectroscopic and DFT studies of some benzimidazole and benzothiazole derivatives
Benzimidazole, benzothiazole and benzoxazole compounds and their derivatives having azole newlinemoieties are biologically active and are extensively used in pharmaceutical industry. newlineBenzimidazoles/benzothiazoles scaffolds have also been widely used as and#61552;and#8722;spacers and newlinedonor/acceptor units. The lone pair electrons and conjugated structures of these heterocyclic molecules assist in tuning of electronic properties enabling their use in devices like dye sensitized solar cells, organic light emitting diodes etc. However, the design and synthesis of organic ligands newlinefor these applications is still a challenging task. Though we have made an effort in this direction fabricating a dye sensitized solar cell with benzimidazole based sensitizer, the moderate Stokes shift and efficiency prompted us to tune these molecules and improve their electronic properties. Considering that some of the benzimidazole/benzothiazole fluorophores possessing metal-ion newlinechelating properties and having hydrogen donor-acceptor sites in close proximity play vital role in sensor and bioimaging applications, we have designed and synthesized novel fluorophores for newlinemetal ion sensing applications. Since most of the available literature shows studies on fluorophores with single excited state intramolecular proton transfer sites or dual proton transfer sites with symmetrical structures, we have considered investigating fluorophores having asymmetrical newlinestructures and proton donating sites. In this perspective, we have synthesized and conducted spectroscopic and density functional theory studies on some novel fluorophores based on benzimidazole/benzothiazole Schiff bases and the details are presented in this thesis. Chapter 1 gives an introduction to the benzimidazole/benzothiazole heterocycles and the different photophysical and chemical phenomena involved. A brief literature survey in support of our studies is presented in Chapter 2. Chapter 3 gives a brief description of the experimental methods newlineand techniques used in our work. -
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Synthesis of ZnO and NiO nano ceramics composite high-performance supercapacitor and its catalytic capabilities
NiO and ZnO mixed nanocomposites were manufactured using the solution combustion process. As-prepared samples were analyzed using XRD. The XRD shows an average crystallite size of 3540 nm. The elemental composition determined by EDS indicates a nearly equal proportion of Ni and Zn, with an atomic ratio of Ni/Zn = 0.96. The specific capacitances of NiO is 295.5 Fg-1, ZnO is 117.3 Fg-1 and ZnO/NiO nanocomposites is 561.75 Fg-1 which are more than NiO and ZnO alone. This study shows that constructing binary oxide nanocomposites is an approach for developing high-performance supercapacitor electrode materials. Experimental observations on catalytic activity revealed that NiO/ZnO increased catalytic activity. Furthermore, adding NiO to ZnO in the composite increased the overall amount of oxygen vacancies in the samples. Our research lays the door for a simple, inexpensive, nontoxic, and quick technique to synthesize binary transition metal oxide-based electrode materials for high-performance supercapacitors. 2024 Elsevier Ltd and Techna Group S.r.l. -
Synthesis of Yttria-Stabilized Zirconia Nano Powders for Plasma Sprayed Nano Coatings
Plasma sprayed Yttria Stabilized Zirconia (YSZ) coatings, with few microns sized microstructure/grain morphology has been well researched, reported and established as an industrial Thermal Barrier Coatings (TBC) material/system. However, nano structured YSZ coatings possess improved characteristics when compared with their micron sized counterparts. However, due to their nano sizes, light weight, and low density, plasma spray coating process of nano powders suffers from flowability issues due to lack of nano powder inertia/momentum, leading to poor deposition/uneven coating thickness. In this research work, nano structured YSZ coatings were synthesized by using an Atmospheric Spray Coating (APS) facility. Nano powders of YSZ were used as the starting materials to prepare micron sized plasma sprayable powders. 80?m thick NiCrAlY bond coat (commercial) and 200?m thick YSZ top coat with nano microstructure (lab synthesized) were built on steel substrates. The starting nano crystalline (YSZ) powders, measuring 30-70 nanometers (nm) were synthesized in the laboratory via chemical method (sol-gel) by employing zirconium oxy chloride hexa-hydrate and yttrium nitrate as precursors, citric acid as chelating agent and ethylene glycol for the diversification reaction followed by calcination @ 1000C. They were then re-constituted into micron sized (53-106 ?m) plasma sprayable powders by agglomerating with polyvinyl alcohol (PVA) binders. The nano crystallite morphology of powders and coatings were analyzed by Scanning Electron Microscope (SEM), chemical composition by Energy Dispersive spectroscopy (EDS) and crystal structural phase by X-ray diffraction (XRD). The influence of calcination temperature of 1150C on nano crystallite morphology was also studied. 2019 Elsevier Ltd. -
Synthesis of Value Added Refractories from Aluminium Dross and Zirconia Composites
Results of a developmental study on the potential to synthesize industrial grade refractories from aluminum dross with un-stabilized zirconia are reported. The merit of the developed product to perform as refractories suitable for use at or above 1000C was assessed by studying the thermo-physical behavior as per guidelines of ASTM and IS. Aluminum dross, an industrial waste (slag) is generated in several millions of tons in the production of Aluminum and is dumped into landfills, which releases poisonous gases like methane and ammonia upon contact with moisture present in the land and the heat generated by the earth, warranting stringent mitigation efforts. Rich in aluminum metal (?15%), ?-Al2O3 (7-15%), MgAl2O4 (10-15%) and AlN (20-30%), the general prime dross composition draws interest due to its abundance and presence of ?-Al2O3 and MgAl2O4, for the production of refractories with insulating, shock resistance and stability at high temperature (?1000C and above) characteristics. Nevertheless, presence of AlN, a good thermal conductor acts as a deterrent in the production of refractories. Aluminium dross (after leaching out AlN) was processed with un-stabilized zirconia (monoclinic ZrO2) to synthesize the refractory composites. Conventional process (calcination, ball milling, compaction and sintering (1550C/6 hrs)) was employed. Characterization involved thermal shock cycling (air quench at furnace ambient of 1000C and room temperature) to determine the number of shock cycles endured before failure. Structural phase analyses at various stages of processing were carried out by via XRD. Magnesia present in dross did not appear to stabilize either the tetragonal or cubic ZrO2. Microstructural and chemical composition studies were carried out via SEM and EDS. The favourable results confirm the viability of the process methodology. 2019 Elsevier Ltd. -
Synthesis of UWB Pulse Shaper for Efficient Pulse Propagation in Human Tissue
In this paper, a filter based pulse shaper is proposed for efficient Ultra-wideband (UWB) pulse transmission through human tissues. A bandpass Finite Impulse Response (FIR) filter is synthesized and its closed form expression for the impulse response coefficients is obtained. The filter shapes the basic UWB pulse, to closely fit the desired Federal Communication Commission (FCC) mask specifications, to achieve high spectral utilization efficiency. In this approach, the effects due to Gibb's phenomenon are minimized thereby resulting in lower dominant sidelobe of the resultant UWB pulse. The interference between adjacent pulses of the UWB data stream is minimized thus it allows shorter duration UWB pulses to be synthesized leading to higher data rate transmission compared to some techniques in literature. 2020 IEEE. -
Synthesis of Thiazines, Thiazinones and N-Cycloalkyl Azoles Via Novel Synthetic Routes
Heterocyclic building blocks have gained the utmost importance in recent past on the newlineaccount of their significance in biological and pharmaceutical fields. Among these newlinenitrogen and sulphur containing heterocyclic building blocks such as thiazines, newlinethiazinones and N-cycloalkyl heterocyclic motifs hold an important role in medicinal newlinechemistry. Thiazine cores are used for the treatment of various life threating diseases newlinelike cancer, cardiovascular and fabry diseases. Drugs containing thiazinone cores were used to treat Parkinson, Alzheimer s and various neuro degenerative diseases. Ncycloalkyl azole motifs are used to treat various life threating cancers like neck, lung, prostate, breast etc. As per the literature review, synthesis of these motifs are done using multi steps and harsh conditions, which limited the substrate scope. In this thesis we describe our studies on development of one pot, mild condition for newlinesynthesis of thiazinone cores using P(NMe2)3 (HMPT). We had developed HMPT [P(NMe2)3] mediated reactions towards synthesis of Carbon-Nitrogen/Carbon-Sulphur bond. The developed methodology was extended for thiazine cores as well. This new synthetic methodology is useful to synthesize various N, S-heterocycles including the novel spiro molecules. HMPT reagent under the mild and aerobic reaction conditions provided the access for many manifold immense molecules. Molecular docking studies were conducted for the synthesized compounds considering MOA-B inhibitors as target. MOA-B inhibitor motifs were approved for the treatment of Parkinson illness. The synthesized thiazine and thiazinone molecules showed good binding affinity in molecular docking studies conducted. We had developed a new strategy using T3P (1-Propanephosphonic anhydride, ~ 50 % wt, in EA solution) mediated synthetic procedure for the synthesis of N-cycloalkyl newlineazoles. -
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Synthesis of spray dried nano 8YSZ plasma sprayable powder and plasma sprayed thermal barrier coatings with nano grained microstructure /
Patent Number: 202241011004, Applicant: S. Gowtham Sanjay.
Plasma sprayed 8% yttria stabilized zirconia, i.e. 8Y203-Zr02(8YSZ) coatings with nano grained microstructure are expected to possess superior thermal barrier properties when compared with the coating of same composition but with large micron sized grains in its microstructure. 8YSZ nano powders were spray dried to be converted into easily flowing micron sized (>20 and <100u) plasma sprayable powders. The powders were plasma spray coated on stainless steel (SSL 304) and Aluminium-silicon (Al-Si) alloy substrates. -
Synthesis of spray dried nano 8YSZ plasma sprayable powder and plasma sprayed thermal barrier coatings with nano grained microstructure /
Patent Number: 202241011004, Applicant: S. Gowtham Sanjay.
Plasma sprayed 8% yttria stabilized zirconia, i.e. 8Y203-Zr02(8YSZ) coatings with nano grained microstructure are expected to possess superior thermal barrier properties when compared with the coating of same composition but with large micron sized grains in its microstructure. 8YSZ nano powders were spray dried to be converted into easily flowing micron sized (>20 and <100u) plasma sprayable powders. The powders were plasma spray coated on stainless steel (SSL 304) and Aluminium-silicon (Al-Si) alloy substrates. -
Synthesis of SnO2-Sodium alginate-polyethylene glycol-crocin nanocomposite for enhanced antimicrobial and anticancer activity
Bacteria and fungi contribute to antibiotic resistance, posing a growing threat to human health, while cervical cancer remains a significant health concern, impacting women's well-being and mortality rates worldwide. In the present work, the efficiency of formulated tin oxide-sodium alginate-polyethylene glycol-crocin nanocomposites (SnO2-SAPEG-Cro-NCs) on antimicrobial as well as growth inhibition and apoptosis induction in cervical cancer cells was evaluated. The developed nanostructure was exposed to several spectroscopic investigations, including UV, FTIR, XRD, PL, EDAX, DLS studies, and FESEM structural observation. The results of the antimicrobial study revealed increased inhibition zones from 8.5 to 16 mm around the SnO2-SAPEG-Cro-NCs treatment over different pathogens, which proves its antimicrobial efficacy. The findings of the MTT study demonstrated that SnO2-SAPEG-Cro-NCs (0.510 ?g/mL) treatment remarkably inhibited the HeLa cell viability with IC50 concentration of 5 ?g/mL. The SnO2-SAPEG-Cro-NCs-treated HeLa cells also revealed increased intracellular ROS generation at 5 and 7.5 ?g/mL, which may facilitate oxidative stress-mediated cell death. Further, the dual staining and DAPI staining results demonstrated that the SnO2-SAPEG-Cro-NCs treatment effectively increased the apoptosis in the cervical cancer HeLa cells. Overall, the outcomes authorized that SnO2-SAPEG-Cro-NCs is an excellent antimicrobial and anticancer agent for future use. 2024 Elsevier B.V. -
Synthesis of Quinoxalin-2(1 H)-ones and Hexahydroquinoxalin-2(1 H)-ones via Oxidative Amidation-Heterocycloannulation
A metal-catalyst-free synthesis of substituted quinoxalin-2-ones from 2,2-dibromo-1-arylethanone by employing an oxidative amidation-heterocycloannulation protocol is reported. The substrate scope of the reaction has been demonstrated and a possible mechanism for this reaction has also been proposed. 2020 GeorgThieme. All Rights Reserved. -
Synthesis of porous graphene sheets from agricultural waste by chemical methods
A facile technique to synthesise wrinkled graphene like nano carbon (GNC) agricultural waste like wood and coconut charcoal is reported in the current study. The charcoal is produced by thermal decomposition of wood and coconut shell and is intercalated by Hummer's method. It is separated by centrifugation and sonication to get few layer graphene sheets. The structural and chemical changes of the nanostructure are elucidated by Raman spectroscopy, TEM, SEMEDS and XPS. Raman spectra revealed the existence of highly graphitized amorphous carbon, which is confirmed by the appearance of five peaks in the deconvoluted first order Raman spectra. The SEM analysis reveals the formation of large area graphene sheets with nanoporous structure in it. The TEM/SAED analysis exhibits the presence of short range few layers graphene. 2018 World Research Association. All rights reserved. -
Synthesis of Online Criminal User Behaviours Disseminating Bengali Fake News Using Sentiment Analysis
Even though research on artificial intelligence (AI) is still in its early phases, the field is growing in popularity. We created a hybrid machine learning model to better understand the pattern of results connected to illegal user behaviour. Then, after identifying the components of illegal user activity, we created a theory for forecasting criminal user behaviour that explains the patterns and results. Our study focuses on offenders spreading misleading information online and makes use of a Bengali dataset. Sentiment analysis is a modern technology that can help us understand how individuals feel in different scenarios during their everyday lives. To comprehend the pattern behind this agenda, machine learning and deep learning techniques will be applied throughout the categorization process. To determine the possible attitudes driving criminal conduct that spreads misleading information, sentiment levels on social media may be monitored or studied. This study examines the use of several artificial intelligence approaches to assess sentiment in social media data in order to identify criminal user activity occurring throughout the world. The hybrid model CNN with Adam optimizer exhibits higher precision levels while doing sentiment analysis. In addition to identifying solutions to the issues that people currently face in the modern world, we also propose a new categorization system for illicit user activity. In our analysis of the research's shortcomings, we make recommendations for a broader research agenda on illicit user conduct and how one can forecast the criminal user behaviour on psychological aspects. Our model was thus able to draw 87.33% accuracy in determining criminal behaviour patterns. The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024. -
Synthesis of novel Se capped polymer photocatalyst mobilized under visible light: Exploration of piezoelectric effect and charge transfer mechanism in polymer matrix
The present study has shown the original and promising usage of zero valent metallic selenium in the photocatalysis process under visible light. Selenium (Se) dispersed into the Polyvinyl Chloride (PVC) and Polyvinylidene Fluoride (PVDF) polymeric solution (Se-PVC/Se-PVDF matrix) by reflux-calcination method. The SEM and TEM results shows Se nanoparticles are well disseminated into the polymer solution and homogenously mixed to avert cluster of particles. The results shows that Se-PVC matrix effectively enhanced the generation rate of photoinduced electrons and reduced transfer resistance endorsed by photoluminescence, transient photocurrent, and electrical impedance spectroscopy techniques. Further, photocatalytic activity studied in presence of potassium iodide (KI) and isopropyl alcohol (IPA). The decrease in photocatalytic activity order is: Se-PVC > Se-PVDF > Se-PVC + KI > Se-PVDF + KI > Se-PVC + IPA > Se-PVDF + IPA systems. The piezoelectricity phenomena and Surface Plasmon Resonance (SPR) effect proposed for Se-PVC/Se-PVDF matrix and correlated with photocatalytic mechanism for the degradation of Methyl Orange (MO). 2023 Elsevier B.V.