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21.
Reema Sarkari Vankudoth Krishna Medak Sudhakar Tumula Venkateshwar Rao Aytam Hari Padmasri Darbha Srinivas Akula Venugopal 《Kinetics and Catalysis》2016,57(5):602-609
The ZnO–ZnCr2O4 (Zn–Cr–O) sample obtained by decomposition of Zn-Cr hydrotalcite precursor was subjected to the thermal treatment at different temperatures and the physico-chemical properties of the Zn–Cr–O system were compared with its catalytic behavior in dehydrocyclization of crude glycerol and ethylenediamine (EDA). Upon high temperature treatment of Zn–Cr–O the Cr6+ ions underwent autoreduction to form stable Cr3+ species and the particle size of both ZnO and ZnCr2O4 increased dramatically. Thermal effect did not influence the intermolecular cyclisation of EDA to form pyrazine. By contrast, an inversely proportional dependence was found between the rate of formation of 2-methylpyrazine and the particle size of Zn–Cr–O whereas the rate of 2-pyrazinylmethanol was directly proportional to the particle size. 相似文献
22.
Catalytic decomposition of CH4 over Ni-Al2O3-SiO2 catalysts: Influence of pretreatment conditions for the production of H2
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Jangam Ashok Gangadhara Raju Padigapati Shiva Reddy Machiraju Subrahmanyam Akula Venugopal 《天然气化学杂志》2008,17(2):113-119
This article reports the production of COx free hydrogen and carbon nanofibers by the catalytic decomposition of methane over Ni-Al2O3-SiO2 catalysts. The influence of reaction temperature, pretreatment temperature, and effect of reductive pretreatment on the decomposition of methane activity is investigated. The physico-chemical characteristics of fresh and deactivated samples were characterized using BET-SA, XRD, TPR, SEM/TEM, CHNS analyses and correlated with the methane decomposition results obtained. The Ni-Al-Si (4 : 0.5 : 1.5) catalyst reduced with hydrazine hydrate produced better H2 yields of ca. 1815 mol H2/mol Ni than the catalyst reduced with 5% H2/N2. 相似文献
23.
Synthesis of Novel Drug‐Like Small Molecules Based on Quinoxaline Containing Amino Substitution at C‐2
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K. Raghavendra Rao Akula Raghunadh Ramamohan Mekala Suresh Babu Meruva K. Ravi Ganesh T. Krishna Dipak Kalita Eppakayala Laxminarayana Manojit Pal 《Journal of heterocyclic chemistry》2016,53(3):901-908
A series of novel “drug‐like” small molecules based on quinoxaline containing amino substitution at C‐2 were synthesized. All these molecules were prepared either via the reaction of 2‐phenyl‐3‐(piperazin‐1‐yl)quinoxaline with acyl bromides or benzyl bromides or various carboxylic acids or via the reaction of 2‐chloro‐3‐phenylquinoxaline with various amines. The structures of these novel compounds were confirmed by spectral analysis. The strategy used is simple and efficient and afforded good yields of quinoxaline derivatives. 相似文献
24.
Chatla Anjaneyulu Velisoju Vijay Kumar Suresh K. Bhargava Akula Venugopal 《Journal of Energy Chemistry》2013,22(6):853-860
Hydrotalcite precursors of La modified Ni-Al2O3 and Ni-SiO2 catalysts prepared by co-precipitation method and the catalytic activities were examined for the production of COx-free H2 by CH4 decomposition. Physico-chemical characteristics of fresh, reduced and used catalysts were evaluated by XRD, TPR and O2 pulse chemisorptions, TEM and BET-SA techniques. XRD studies showed phases due to hydrotalcite-like precursors in oven dried form produced dispersed NiO species upon calcination in static air above 450 °C. Raman spectra of deactivated samples revealed the presence of both ordered and disordered forms of carbon. Ni-La-Al2O3 catalyst with a mole ratio of Ni : La : Al = 2 : 0.1 : 0.9 exhibited tremendously high longevity with a hydrogen production rate of 1300 molH2 ·mol?1Ni. A direct relationship between Ni metal surface area and hydrogen yields was established. 相似文献
25.
Hydrotalcite precursors of La modified Ni-Al2O3 and Ni-SiO2 catalysts prepared by co-precipitation method and the catalytic activities were examined for the production of COx-free H2 by CH4 decomposition. Physico-chemical characteristics of fresh, reduced and used catalysts were evaluated by XRD, TPR and O2 pulse chemisorptions, TEM and BET-SA techniques. XRD studies showed phases due to hydrotalcite-like precursors in oven dried form produced dispersed NiO species upon calcination in static air above 450 C. Raman spectra of deactivated samples revealed the presence of both ordered and disordered forms of carbon. Ni-La-Al2O3catalyst with a mole ratio of Ni : La : Al = 2 : 0.1 : 0.9 exhibited tremendously high longevity with a hydrogen production rate of 1300 molH2 mol 1 Ni. A direct relationship between Ni metal surface area and hydrogen yields was established. 相似文献
26.
Reddy DC Bapuji AT Rao VS Himabindu V Ravinder S 《Journal of chromatographic science》2012,50(6):538-546
A rapid and high sensitive liquid chromatography-tandem mass spectrometry (LC-MS-MS) method was developed and validated for the quantification of zolpidem in human EDTA plasma using ondansetron (IS) as an internal standard. The analyte and IS were extracted from human plasma using ethyl acetate and separated on a C18 column (Inertsil-ODS, 5 μm, 4.6 × 50 mm) interfaced with a triple quadrupole tandem mass spectrometer. The mobile phase, which consisted of a mixture of methanol and 20 mM ammonium formate (pH 5.00 ± 0.05; 75:25 v/v), was injected at a flow rate of 0.40 mL/min. The retention times of zolpidem and IS were approximately 1.76 and 1.22. The LC run time was 3 min. The electrospray ionization source was operated in positive ion mode. Multiple reaction monitoring used the [M + H](+) ions m/z 308.13 → 235.21 for zolpidem and m/z 294.02 → 170.09 for the ondansetron, respectively. Five freeze-thaw cycles was established at -20 and -70°C.The linearity of the response/concentration curve was established in human EDTA plasma over the concentration range 0.10-149.83 ng/mL. The lower detection limit [(signal-to-noise (S/N) > 3] was 0.04 ng/mL and the lower limit of quantification (S/N > 10) was 0.10 ng/mL. This LC-MS-MS method was validated with intra-batch and inter-batch precision of 0.52-8.66.The intra-batch and inter-batch accuracy was 96.66-106.11. Recovery of zolpidem in human plasma was 87.00% and IS recovery was 81.60%. The primary pharmacokinetic parameters were T(max) (h) = (1.25 ± 0.725), C(max) (ng/mL) (127.80 ± 34.081), AUC(0→t), = (665.37 ± 320.982) and AUC(0→∞), 686.03 ± 342.952, respectively. 相似文献
27.
[structure: see text] Novel ter(9,9-ditolylfluorene) analogues containing thiophene and pyridine rings embedded as functional constituents within the parent hydrocarbon backbone have been synthesized. These new molecules exhibit highly efficient photoluminescence and high thermal and morphological stability. The electronic structure of the terfluorene backbone is significantly perturbed, which allows modulation of the backbone energy levels. 相似文献
28.
Akula Raghunadh Suresh Babu Meruva Ramamohan Mekala K. Raghavendra Rao Thalishetti Krishna R. Gangadhara Chary L. Vaikunta Rao U.K. Syam Kumar 《Tetrahedron letters》2014
An efficient synthesis of unsymmetrically substituted 1,3-pyrazole derivatives has been developed via three-component coupling reaction involving 3-(dimethylamino)-1-phenylprop-2-en-1-one, hydrazine, and aryl halides in one pot process exhibiting high regioselectivity. The pyrazole synthesis proceeds via a sequential series of reactions such as Michael addition, heterocyclization, dehydration, and Ullmann cross-coupling. 相似文献
29.
Suresh Babu Meruva Ramamohan Mekala Akula Raghunadh K. Raghavendra Rao Vilas H. Dahanukar T.V. Pratap U.K. Syam Kumar P.K. Dubey 《Tetrahedron letters》2014
Total synthesis of ent-diospongin A and epimer-diospongin B has been accomplished in good yield with high optical purity. The key steps of diospongin synthesis involve Julia–Kocienski olefination, Weinreb amide formation, Grignard reaction, reduction, acetonide deprotection, Lewis acid catalyzed cyclization, and Wacker oxidation. 相似文献
30.
Akula Aneesh Reddy Siddhartha Banerjee Aditya Gopalan Sanjay Shakkottai Lei Ying 《Queueing Systems》2012,72(3-4):193-218
We study the problem of distributed scheduling in wireless networks, where each node makes individual scheduling decisions based on heterogeneously delayed network state information (NSI). This leads to inconsistency in the views of the network across nodes, which, coupled with interference, makes it challenging to schedule for high throughputs. We characterize the network throughput region for this setup, and develop optimal scheduling policies to achieve the same. Our scheduling policies have a threshold-based structure and, moreover, require the nodes to use only the “smallest critical subset” of the available delayed NSI to make decisions. In addition, using Markov chain mixing techniques, we quantify the impact of delayed NSI on the throughput region. This not only highlights the value of extra NSI for scheduling, but also characterizes the loss in throughput incurred by lower complexity scheduling policies which use homogeneously delayed NSI. 相似文献