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31.
P. Lakshmi Reddy D. Ashok Kumar M. Lakshmi Devi T. Veera Reddy B.V. Subba Reddy R. Narender 《Tetrahedron letters》2014
A three-component, four center Ugi reaction of 3-(1-(2-aminophenyl)-5-phenyl-1H-pyrrol-2-yl)propanoic acid with aromatic aldehyde and t-butyl isocyanide has been achieved to produce a novel class of N-tert-butyl-2-(6-oxo-11-phenyl-7,8-dihydrobenzo[b]pyrrolo[1,2-d][1,4]diazacine-5(6H)-yl)-2-phenylacetamides in moderate to good yields. 相似文献
32.
Fe(Cp)2BF4 is an efficient catalyst for the alcoholysis of aromatic, aliphatic, and cyclic epoxides giving excellent yields of the corresponding β-alkoxy alcohols under ambient conditions. The methanolysis of styrene oxide using Fe(Cp)2BF4 as a catalyst (5 mol %) gave excellent yield of 2-methoxy-2-phenylethanol with complete regio-selectivity. The ring opening of cyclic epoxides gave 77–97% yields of trans-β-methoxy alcohols, in 0.5–6 h. The use of 1,2-epoxyhexane and 1,2-epoxydodecane as substrates gave both regioisomers in excellent yields. The first order rate of reaction with respect to catalyst was observed for the kinetics of ring opening of 1,2-epoxyhexane with methanol. 相似文献
33.
Indirect electrochemical synthesis of quinone derivatives of a series of substituted anthracene and naphthalene by the electrolysis of aqueous solution of potassium bromide (3.0 M) using Pt anode at constant current density (40 mA/cm2) has been carried out. These reactions resulted in good to excellent yields of the corresponding para-quinones as confirmed by physical and spectral data. 相似文献
34.
Durga Charan Panigrahi Patitapaban Sahu Devi Prasad Mishra Vivekanand Jha R. Lokeswara Patnaik 《Journal of Radioanalytical and Nuclear Chemistry》2014,302(1):433-439
This paper presents the assessment of inhalation exposure potential of broken uranium ore piles in different stopes of Jaduguda uranium mines of India. 222Rn emanation coefficient of broken uranium ore was measured in laboratory by collecting air sample from airtight glass jar containing ore sample. An attempt was also made to correlate the emanation coefficient with 226Ra content of the ore. The 222Rn progeny doses estimated based on radon activity concentration of broken ore, occupancy period and equilibrium ratio in different stopes were well below the prescribed limit of International Commission on Radiological Protection. The maximum 222Rn progeny dose contribution from broken ore piles was worked out to be 0.22 mSv year?1. This suggests that the broken ore piles are not the significant contributor of inhalation exposure under the existing ventilation condition of Jaduguda uranium mine. 相似文献
35.
Dr. Srivari Chandrasekhar Kakita Veera Mohana Rao Mallikanti Seenaiah Police Naresh Ambure Sharada Devi Dr. Bharatam Jagadeesh 《化学:亚洲杂志》2014,9(2):457-461
Hybrid peptidic oligomers comprising natural and unnatural amino acid residues that can exhibit biomolecular folding and hydrogen‐bonding mimicry have attracted considerable interest in recent years. While a variety of hybrid peptidic helices have been reported in the literature, other secondary structural patterns such as γ‐turns and ribbons have not been well explored so far. The present work reports the design of novel periodic γ‐turns in the oligomers of 1:1 natural‐α/unnatural trans‐β‐norborenene (TNAA) amino acid residues. Through DFT, NMR, and MD studies, it is convincingly shown that, in the mixed conformational pool, the heterogeneous backbone of the hybrid peptides preferentially adopt periodic 8‐membered (pseudo γ‐turn)/7‐membered (inverse γ‐turn) hydrogen bonds in both polar and non‐polar solvent media. It is observed that the stereochemistry and local conformational preference of the β‐amino acid building blocks have a profound influence on accessing the specific secondary fold. These findings may be of significant relevance for the development of molecular scaffolds that facilitate desired positioning of functional side‐chains. 相似文献
36.
Borah Preetismita Chetan Sharma Vaishali Malakar Arindam Bhinder Surinder Singh Kansal Sushil Kumar Devi Pooja 《Chromatographia》2022,85(2):213-218
Chromatographia - In this work, we present a new method for the determination and speciation of selenium in water with ion chromatography (IC) using a conductometric detector. Chromatographic... 相似文献
37.
The worldwide demand for energy continues to grow and the production of heavy crude is escalating due to shortage of conventional light crude. The transportation of heavy crude oil from the head-well to the refinery is a challenging task due to its high viscosity and low API gravity. Catalytic aquathermolysis is one of the most significant and cost-effective viscosity reduction techniques employed in the up gradation of the crude oil at elevated temperatures and hence to enhance oil extraction process. In this study, catalytic aquathermolysis of Omani heavy crude oil was performed using magnetite nanoparticles (NPs). The NPs were synthesised by reverse co-precipitation method using iron salts in alkaline medium. The synthesised NPs were characterized using Scanning Electron Microscopy (SEM), X-Ray Powder Diffraction (XRD), Energy Dispersive X- Ray analysis (EDX) and Fourier Transform Infrared Spectroscopy (FTIR). The XRD results exhibited a characteristic peak confirming the high purity of iron oxide nanoparticles. The FTIR spectral analysis designated two well-defined peaks corresponding to wave numbers of 500 ?cm?1 and 630 ?cm?1, endorses the presence of Fe–O. The catalytic aquathermolysis experiments were carried out in a Parr high temperature-high pressure batch reactor at different experimental conditions. The processing parameters in temperature range of 250 ?°C - 300 ?°C, 0.1% to 0.3% catalyst loading, water to oil ratio of 1:7 to 3:7 with 24–72 ?h of reaction time. The initial pressure in the reactor was maintained at 32 ?bars and the optimization was performed using the Taguchi method to maximize the level of heavy oil. An orthogonal array was employed to analyse the effects of mean response and mean signal-to-noise ratio (S/N) to upgrade the heavy oil. The regression analysis was used to establish a relationship between the viscosity and experimental parameters. The experimental outcomes indicates that the maximum reduction in viscosity occurred at a processing temperature of 300 ?°C, 1:7 ?W/O ratio, 0.1 ?wt% of catalyst concentration and 48 ?h of reaction time. Similarly, the optimum conditions for the reduction in API gravity were obtained at 280 ?°C temperature, 3:7 ?W/O ratio, 0.2 ?wt% of catalyst concentration and a reaction time of 24 ?h. 相似文献
38.
Oil refinery is one of the fast growing industries across the globe and it is expected to progress in the near future. The worldwide increase in the generation of refinery wastewater along with strict environmental regulations in the discharge of industrial effluent, persistent efforts have been devoted to recycle and reuse the treated water. The wastewater from the refining operation leads to serious environmental threat to the ecosystem. Therefore, this study aimed to synthesize silica (SiO2) and calcium carbonate nanoparticles (CaCO3) in the reduction of organics from refinery wastewater. The synthesized nanoparticles were employed in the reduction of chemical oxygen demand (COD) from refinery wastewater by studying the influence of solution pH, contact time, dosage of nanoparticles and stirring speed on adsorption performance. From the batch experimental studies, the optimized processing conditions for the reduction of COD using SiO2 nanoparticles are pH 4.0, dosage 0.5 g, stirring speed 125 rpm and 90 min stirring time, and the corresponding values for CaCO3 nanoparticles are pH 8.0, dosage 0.4 g, stirring speed 100 rpm and 90 min stirring time. The study demonstrates that SiO2 and CaCO3 nanoparticles have a promising future in the reduction organics from refinery wastewater in different pH regimes. 相似文献
39.
The spectroscopic properties of Nω-nitro-l-arginine were investigated by FT-IR, UV-VIS, and 1H NMR spectra. Geometrical parameters and energies were calculated using the density functional theory (DFT) B3LYP method with the 6-311G basis set. Geometrical optimization of the molecule has been performed, vibrational spectra have been calculated, and fundamental vibrations have been determined from the total energy distribution (TED) of the vibrational modes. The HOMO-LUMO analysis is carried out for various electric fields (0.0–0.025 A?1). The HOMO-LUMO gap is decreased while increasing the electric field. The calculated quantum chemical parameters are calculated and correlated to the inhibition efficiency, A Mullliken population was also important for determining local reactivity by indicating reactive centers and identifying potential nucleophilic and electrophilic attack sites. Charge transfer occurs inside the compound based on the HOMO LUMO gap. Calculations of DFT were evaluated in their ability to predict inhibition efficiency. 相似文献
40.
Understanding the physicochemical properties and heterogeneous processes of aerosols is key not only to elucidate the impacts of aerosols on the atmosphere and humans but also to exploit their further applications, especially for a healthier environment. Experiments that allow for spatially control of single aerosol particles and investigations on the fundamental properties and heterogeneous chemistry at the single-particle level have flourished during the last few decades, and significant breakthroughs in recent years promise better control and novel applications aimed at resolving key issues in aerosol science. Here we propose graphene oxide (GO) aerosols as prototype aerosols containing polycyclic aromatic hydrocarbons, and GO can behave as two-dimensional surfactants which could modify the interfacial properties of aerosols. We describe the techniques of trapping single particles and furthermore the current status of the optical spectroscopy and chemistry of GO. The current applications of these single-particle trapping techniques are summarized and interesting future applications of GO aerosols are discussed. 相似文献