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91.
A stereoselective total synthesis of oplopandiol, oploxyne A, and (−)-oploxyne B is described. The key reactions include Sharpless asymmetric epoxidation, d-proline catalyzed aminoxylation, Cadiot–Chodkiewicz cross-coupling reaction, m-CPBA induced substrate-controlled stereoselective epoxidation, and Lewis acid catalyzed stereo- and regioselective ring-opening of epoxide. 相似文献
92.
Mahendra Yadav Sushil Kumar Rajesh Ranjan Sinha Sumit Kumar 《Journal of Dispersion Science and Technology》2014,35(12):1751-1763
Imidazole derivatives, namely, 1-((1-(piperazinomethyl)-1H-benzoimidazol-2-yl)methyl)-2-phenylhydrazine (PBIP), and 1-((1-(morpholinomethyl)-1H-benzoimidazol-2-yl)methyl)-2-phenylhydrazine (MBIP) were synthesized and investigated as inhibitors for mild steel corrosion in 15% HCl solution using weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) techniques. It was found that the inhibition efficiency of both the inhibitors increases with increase in concentration of inhibitors and decreases with increase in temperature. The inhibitors, PBIP and MBIP, show corrosion inhibition efficiency of 92.6% and 91.4% at 300 ppm concentration, respectively, at 303 K. Polarization studies showed that both the studied inhibitors were of mixed type in nature. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were performed for surface study of uninhibited and inhibited mild steel samples. The semi-empirical AM1 method was employed for theoretical calculations. 相似文献
93.
Manjulata Yadav Mukesh Rawat Anoop Dangwal Mukesh Prasad G. S. Gusain R. C. Ramola 《Journal of Radioanalytical and Nuclear Chemistry》2014,302(2):869-873
Distribution of natural radionuclide gives significant parameter to assess the presence of gamma radioactivity and its radiological effect in our environment. Natural radionuclides are present in the form of 226Ra, 232Th and 40K in soil, rocks, water, air, and building materials. Distribution of natural radionuclides depends on the type of minerals present in the soil and rocks. For this purpose gamma spectrometer is used as tool for finding the concentration of these radionuclides. The activity concentration of naturally occurring radionuclides 226Ra, 232Th and 40K in these soil samples were found to vary from of 8 ± 1 Bq/kg to 50 ± 10 Bq/kg with an average 20 Bq/kg, 7 ± 1–88 ± 16 Bq/kg with an Average 26 Bq/kg and 115 ± 18–885 ± 132 Bq/kg with an average 329 Bq/kg, respectively. In this paper, we are presenting the radiological effect due to distribution of natural radionuclide present in soil of Garhwal Himalaya. 相似文献
94.
Kumar Mukesh Kumar Pankaj Agrawal Anshu Sahoo B. K. 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(2):715-726
Journal of Radioanalytical and Nuclear Chemistry - Dissolved radon (222Rn) in drinking water has been measured using SMART RnDuo, a continuous radon monitor. Water samples have been collected from... 相似文献
95.
GVSRPavan Kumar KSrinivasa Rao Arunendra Yadav MLakshman Kumar HSainadh Dora 《印度化学会志》2022,99(5):100338
Groundwater quality is the major concern all over the world. Natural processes and manmade activities are the prime reasons for the contamination of available water resources. It is crucial to assess the quality of groundwater in areas surrounded by various industries. The present study was carried out to assess the groundwater quality during pre-monsoon and post monsoon seasons of 2016, in two mandals of Vizianagaram district of Andhra Pradesh via multivariate statistical analysis and water quality index method. The present work gains importance in light of the construction of proposed international airport at Bhohapuram and the existence of various industries in Pusapatirega mandal. A total of thirty-seven villages, eighteen from Bhogapuram mandal and seventeen from Pusapatirega mandal were selected for the present study. Factor analysis, linear regression analysis, correlation matrix analysis and cluster analysis tools were used to emphasize the parameters influencing quality of water in the chosen study area. From the analysis reports, it was found that the groundwater of the two mandals under investigation was strongly influenced by EC, TDS, total hardness(TH), Ca+2, Mg+2 and K+. During the two seasons under study, the water quality index value was found to be greater than 100 indicating that the water is unfit for human consumption. Concentration of Ca+2, Mg+2 and K+ were found to be beyond the permissible limits prescribed by BIS (2012). Dissolution of calcium and magnesium bearing minerals, mixing of industrial and household wastes may be the reasons for elevated concentration levels of these parameters. 相似文献
96.
Aradhya Dev Srivastav Vireshwar Singh Deepak Singh Sunita Singh Suresh Kumar Patel Dilip Kumar Sudeep Yadav Balendu Shekher Giri Dhananjay Singh 《印度化学会志》2022,99(8):100632
Nelumbo nucifera leaves are rich source of natural wax possessing super-hydrophobic properties. It provides protection to them from ecological turbulences and climatic wear and tear. In this study, various experiments have been conducted to observe the yield of extraction and the determination of various functional groups, which are present in natural wax, derived from Nelumbo nucifera leaves. The natural wax has been extracted from lotus leaves through non-polar (hexane) and polar (ethanol) solvent via different extraction methods. The superhydrophobic wax has been successfully extracted with hexane. Whereas, ethanol did not extract the water-repellent wax of lotus leaf. Considering the cumulative amount, i.e. (desired + undesired), the maceration shows the extraction of 2.9% (%w/w, through hexane) and 10.2% (%w/w, through ethanol), while it was found 2.5% (%w/w, cycle period 15 min) and 9.0% (%w/w, cycle period 26 min) respectively, in case of Soxhlet extraction technique. For this specific case of natural wax recovery from biomass (lotus leaf), the maceration (traditional method) resulted a little bit superior extraction yield in comparison to the Soxhlet extraction method for extraction of crude wax. In the case of non-polar solvent (hexane), an extraction yield of 1.97% (%w/w) through maceration method was observed while in the case of non-polar solvent (ethanol), an extraction yield of 1.62% (%w/w) through Soxhlet extraction was observed. The TLC analysis on both types of extracts was performed. For the detection of various hydrocarbon chains in the crude wax extracts, FTIR was also performed. Topography of wax surface and wax-coated waterproof fabric was compared through SEM. 相似文献
97.
Jyoti S. Gokhale Moreshwar P. Hude Ganapati D. Yadav Morgan Thomas Janusz Kozinski Ajay K. Dalai 《印度化学会志》2022,99(9):100647
An ongoing major outbreak of mountain pine beetle in Western Canada has provided a clear opportunity to utilize waste pinewood as a source of renewable energy. Therefore hydrothermal processing of waste pinewood as a feedstock for bio-oil and biochar production using subcritical and supercritical water technology was carried out in semi-batch mode to investigate the effect of pressure (200–400 bar) and temperature (300–400 °C) on the yield and composition of bio-oil. The pinewood samples have very high cellulose and hemicellulose content but low ash content and are thus a formidable feedstock for bioenergy production. The optimum conditions for the hydrothermal processing of the pinewood in a tubular reactor were found to be 400 °C and 250 bars with respect to biochar and bio-oil yield based on the highest calorific value analysis. Detailed characterization of bio-oil and biochar was performed using GCMS, NMR, SEM, calorific value, and elemental analysis, respectively. The critical components of bio-oil were found to be phenols, methoxyphenols, hydroxymethyl furfural (HMF), and vanillin, whereas as compared to the raw pine wood, the biochar was considerably lower H:C and O:C ratios than those of the unprocessed pinewood. The analyses of bio-oil by means of GCMS and 1H NMR showed that it was mainly composed of heterocyclic compounds, phenols, aldehydes and acids. 相似文献
98.
Seunghyun Jeong Joon Ho Yoon Pankaj Attri In Tae Kim 《Journal of Saudi Chemical Society》2021,25(5):101227
Over the past few years, polymers shown comprehensive utilization in optical devices, solar cells, sensors, and other such devices. However, the efficiency of these devices remains a problem. We have synthesized new thiophene based, lowband gap polymer, poly(2-heptadecyl-4-vinylthieno[3,4-d] [1,3] selenazole) (PHVTS) and investigated the interactions between the PHVTS and ionic liquids (ILs), in this study. We have used imidazolium- and ammonium-family ILs, and studied the interactions using various spectroscopic techniques such UV–visible, FTIR, and confocal Raman spectroscopies. Additionally, we studied surface morphology of the polymer-IL film. Spectroscopic studies show that both families of ILs can interact with the newly synthesized polymer poly(2-heptadecyl-4-vinylthieno[3,4-d] [1,3] selenazole). However, the imidazolium-family Ionic Liquid-polymer (IL-polymer) mixture films show higher conductivities than ammonium-family IL–polymer mixture films. 相似文献
99.
Structural Chemistry - Mononuclear and dinuclear iron complexes are found as key intermediates in many synthetic and biocatalytic reactions, since many of these species are transient and have high... 相似文献
100.
The thermodynamic properties, such as free energy of mixing, heat of mixing, activity and structural properties, such as concentration fluctuation in long wavelength limit, short-range order parameter of Pb–Hg liquid alloy at 600 K have been calculated using theoretical modelling. It has then been correlated with modified Butler model to compute the surface tension of the alloys at different temperatures. The Pb–Hg system at 600 K is found to be ordering at higher concentration of Pb. 相似文献