Oxidation of Some Biologically Important Organic Substrates by Lipopathic Cr(VI) and Mn(VII): Kinetics and Mechanistic Study

The search for novel oxidants has been ongoing due to the advancements in the synthesis of complex organic molecules under different reaction conditions. Most oxidation reactions employ inorganic oxidants with metal ions of Cr(VI), Mn(VII), Ce(IV), Fe(III), Ru(IV), V(V) etc. However, the poor solubility of these inorganic oxidants in nonaqueous media restricts their use for the oxidation of water insoluble organic substrates. To undertake reactions of organic substrates in organic homogeneous media, tailor made lipopathic oxidants are of much interest. Onium ions (generally refer to hypervalent ammonium, phosphonium, arsonium, tellurium ions etc,) having alkyl groups are attached as counterions to carry the oxidant from aqueous medium into organic medium. Due to amphipathic characteristics of these onium ions and resultant ion pair characteristics with the anionic counterpart the solubility, reactivity, and redox potentials of the oxidants vary significantly. These reagents are found to be mild, chemoselective and regioselective.With an objective to develop new efficient, selective and mild oxidation protocols, the oxidizing ability of some lipopathic oxidants namely cetyltrimethylammonium dichromate (CTADC), cetyltrimethylammonium permanganate (CTAP) and cetyltrimethylammonium cericnitrate (CTACN) has been explored by our research group using cetyltrimethylammonium (CTA) ion as the onium counterion for anionic dichromate, permanganate and cericnitrate. The CTA ion is well known for its amphipathicity, which is having the characteristics of being solubilized in both aqueous and non-aqueous media. Unlike other quaternary ammonium ions (tetrabutyl or tetraoctyl ammonium ions), the CTA ion has a relatively small head group with more exposed charge and a well-balanced hydrophobic group to carry the ions to both water and organic media and thus is a magic amphiphile. Its balanced amphiphilic system makes it capable to form various artificial organized assemblies such as micelles, reverse micelles, microemulsions, vesicles etc. The preliminary reports on oxidation of various mono- and bi-functional organic substrates by CTADC and CTAP show their mildness and chemoselectivity. The present research work aims at employing CTADC and CTAP to study the oxidative metabolism of some established drugs such as acetaminophen, epinephrine, isoniazid, carbamazepine and norfloxacin having multiple functional groups in nonaqueous medium.To achieve the objectives, the oxidation product(s) were isolated and characterized. The reaction kinetics was studied using UV-vis spectrophotometric method in different media with varied polarities and also in micro-heterogeneous systems generated due to the presence of surfactants. Suitable mechanisms have been proposed and supplemented by proper evidences such as deuterium kinetic isotope effect, solvent kinetic isotope effect, effect of medium, effect of temperature, effect of surfactants etc. The selectivity, mildness and biomimetic characteristics of the oxidative cleavage have been discussed and compared with that of the existing literature reports. Possibilities to utilize these oxidants as biomimetic chemical oxidation model have been explored primarily to synthesize the selective metabolites of drug candidates and to study the mechanism of oxidation at lipid-solution interfaces.The present thesis entitled, “Oxidation of some biologically important organic substrates by lipopathic Cr(VI) and Mn(VII) : Kinetics and mechanistic study” comprises of seven chapters..

Understanding of MILD Combustion Characteristics of NH3 Air Flames in N2 And H2O Steam Diluted Environment at Atmospheric Pressure

Ammonia is becoming increasingly popular as a carbon-neutral fuel with zero carbon dioxide emissions. However, a significant hurdle lies in its combustion, which leads to substantial emissions of NOx. The current research involves conducting a chemical kinetic investigation to examine the characteristics of Intense Low oxygen Dilution (MILD) or Moderate combustion in ammonia (NH3)/air flames. This study is carried out under specific conditions, such as oxygen concentrations ranging from 11to 23%, premixed reactant temperatures between 1300 and 1700 K, and a pressure of one atmosphere. The study focuses on investigating the combustion characteristics of MILD using dilution with H2O and N2.With the rise in the inlet temperature of the premixed reactant, the peak temperature of the flame also rises. Moreover, flames diluted with H2O exhibit lower peak temperatures compared to flames diluted with N2.Flames diluted with H2O result in lower NOx emissions compared to flames diluted with N2. Additionally, for N2diluted flames, the exit NOx emissions rise as the oxygen concentration increases.Despite this, NOx emissions from H2Odiluted flames demonstrate non-monotonic behaviour.This means that the exit NOx increases initially as the oxygen concentration reaches 21%, but then begins to decrease. In contrast to N2and H2Odiluted flames exhibits a wider regime of no-ignition.Moreover, the rise in peak temperature in H2Odiluted flames is less apparent than in N2diluted flames, corresponding to broader ranges MILD combustion ranges.Furthermore, to attain MILD combustion in H2O diluted flames at a specific O2 concentration, the temperature of reactant needs to be higher than that required for N2diluted flames. &nbsp

Design and analysis of effective graded microwave absorbing material for low observable technology

629-634Compositional designing of effective graded radar absorbing material for low observable technology is always a challengeable task in material science. The micro scale or quantum scale interaction of electromagnetic radiation is depends on the characteristic property of each atom or their assembly in a material composition. The filler and matrix in a composite structure plays a vital role between the advantages in electromagnetic absorption capability and the disadvantage due to difficulties in practical homogenous dispersion with weight concentration. The present work describes synthesis of biomaterial based effective graded radar absorbing material (RAM) for application in stealth technology. Ultrasonic treated rice husk raw material shows a significant increase of dielectric property of the composite material blended with epoxy resin. The significant modification in surface of the biomaterials with ultrasonic wave provides the enhanced mechanical strength as well as hardness of the material. Bio ceramic material composed of china clay and carbon rich waste rice husk ash possesses good dielectric loss for frequency 10 GHz and reflection loss -24.5 dB which is quite significant for stealth technology. Scanning electron microscopy (SEM) study shows good dispersion of rice husk ash in the epoxy matrix. Frequency dependence of both dielectric constant and dielectric loss are measured in the X band frequency range (8.2-12.4GHz). This low cost laboratory scale synthesized RAM find its application in designing of stealth aircraft and jet fighter for military purposes

Design and analysis of effective graded microwave absorbing material for low observable technology

Compositional designing of effective graded radar absorbing material for low observable technology is always a challengeable task in material science. The micro scale or quantum scale interaction of electromagnetic radiation is depends on the characteristic property of each atom or their assembly in a material composition. The filler and matrix in a composite structure plays a vital role between the advantages in electromagnetic absorption capability and the disadvantage due to difficulties in practical homogenous dispersion with weight concentration. The present work describes synthesis of biomaterial based effective graded radar absorbing material (RAM) for application in stealth technology. Ultrasonic treated rice husk raw material shows a significant increase of dielectric property of the composite material blended with epoxy resin. The significant modification in surface of the biomaterials with ultrasonic wave provides the enhanced mechanical strength as well as hardness of the material. Bio ceramic material composed of china clay and carbon rich waste rice husk ash possesses good dielectric loss for frequency 10 GHz and reflection loss -24.5 dB which is quite significant for stealth technology. Scanning electron microscopy (SEM) study shows good dispersion of rice husk ash in the epoxy matrix. Frequency dependence of both dielectric constant and dielectric loss are measured in the X band frequency range (8.2-12.4GHz). This low cost laboratory scale synthesized RAM find its application in designing of stealth aircraft and jet fighter for military purposes

Integrated nutrient management module to improve productivity and economics of short grain aromatic rice (Oryza sativa)- greengram (Vigna radiata) sequence

The present field study was carried out during 2017–18 and 2018–19 rainy (kharif) and winter (rabi) seasons in order to examine the impact caused by integrated nutrient management (INM) on the yield and quality of the short grain aromatic rice (Oryza sativa L.)-greengram (Vigna radiata L.) combination. Two years experimental data concluded that integration of 50% recommended dose (RD) as fertilizer + 50% RD of nitrogen via farm yield manure (FYM) resulted in considerably higher economic yield (3837.1 and 3917.7 kg/ha) of short grain aromatic rice cv. Nua Acharamati which were at par with 75% RD as fertilizer + green manuring of dhaincha (3438.5 and 3539.1 kg/ha). Pooled data revealed that, residual effect of 50% RD as fertilizer + 50% RD of nitrogen (FYM) and 75% RD as fertilizer + Rhizobium + PSB in greengram recorded the highest number of pods/plant (18.2), seeds/pod (11.3), pod length (9.3 cm), test weight (32.7 g), seed yield (925.7 kg/ha) and stover yield (2240.7 kg/ha) in greengram cv. IPM-02-03. Application of 50% RD as fertilizer + 50% RD of nitrogen (FYM) to aromatic rice recorded the highest hulling recovery (75.8 and 75.5%), milling recovery (68.0 and 68.3%), head rice recovery (60.0, 59.7%) and crude protein content (8.75 and 9.11%) during both of the years experiment being at par with application of 75% RD as fertilizer + green manuring. Economics of the system revealed the highest gross return, net return and B:C ratio by application of 50% RD as chemical fertilizer + 50% RD of nitrogen (FYM) in rice followed by 75% RD as chemical fertilizer + Rhizobium + PSB in greengram

GPS Based Soil Profile Study in Respect to Morphological and Nutrient Analysis in Pedon of Ganjam District

GPS based two pedons- one each from up and medium land during dry season, studied in the field &amp; analysis done in the laboratory. The difference in properties between two pedons was mostly due to lateritic and basaltic parent material in pedons. The morphology of mineral soils explains the evolution that occurs in the soil body during the process of soil formation, which is predominantly influenced by the parent material and climate. Determination of epipedon and endopedon of diagnostic horizons through description and interpretation of soil profile properties is the basis of land classification, as the knowledge of soil properties, capabilities, and utilization. The results of the study found that, based on its morphological and chemical characteristics, the soil in pedon 1 had brighter colors, higher micronutrient availability, and a thicker horizon compared to the soil in pedon 2. Meanwhile, the pedon 1 is light texture, crumb structure and pedon 2 is heavy texture and sub angular blocky structure. Both the form of density in two pedons was increasing downwards &amp; the value were of a typical mineral soils, but the pore space showed a reverse trend on confirming the compactness and aging of soils towards subsurface horizons. Same results tendency found in micronutrients analysis where pedon 1 rich in micronutrients as compare to pedon 2.</jats:p