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41.
Susmitha Uppugalla Rajender Boddula Palaniappan Srinivasan 《Journal of Solid State Electrochemistry》2018,22(2):407-415
In this work, organic-inorganic composite materials of polyaniline and manganese oxide were synthesized and investigated their electrochemical performance. This composite material was prepared by oxidizing aniline with methyl triphenylphosphonium permanganate as a novel organic oxidant via aqueous, emulsion, and interfacial polymerization pathways. This process led to the formation of polyaniline-sulfate salt (PANI-SA-Mn5O8). Formation of polyaniline-sulfate salt was confirmed from FT-IR, EDAX, and XRD results. Formation of Mn5O8 was supported by XRD spectrum. PANI-SA-Mn5O8 prepared via emulsion polymerization pathway was obtained in porous nanorod morphology with high conductivity (9.4 S cm?1) compared to that of the other sample prepared via interfacial pathway (1.7 S cm?1). Whereas, aqueous polymerization pathway resulted in sheet-like morphology with a conductivity of 0.8 S cm?1. These composites were used as pseudocapacitive electrode materials. Electrochemical characterization (cyclic voltammetry, charge-discharge, and electrochemical impedance measurement) showed that composite prepared via emulsion polymerization pathway gave better electrochemical performance, and showed good cycling behavior. 相似文献
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Syntheses and structures of isomeric [6.6]- and [8.8]cyclophanes with 1,4-dioxabut-2-yne and 1,6-dioxahexa-2,4-diyne bridges 总被引:1,自引:0,他引:1
Srinivasan M Sankararaman S Hopf H Dix I Jones PG 《The Journal of organic chemistry》2001,66(12):4299-4303
All three isomers (ortho, meta, and para) of [8.8]cyclophane bearing 1,6-dioxahexa-2,4-diyne bridges have been synthesized and structually characterized by single-crystal X-ray crystallography to determine the conformation of the cyclophanes and their cavity dimensions. The three isomeric [6.6]cyclophanes bearing 1,4-dioxabut-2-yne bridges have also been synthesized from but-2-yne-1,4-diol ditosylate and the isomeric dihydroxybenzenes. The [6.6]orthocyclophane has been structurally characterized by single-crystal X-ray crystallography. The energy-minimized structures from the semiempirical AM1 calculations of these cyclophanes compare very well with the structures obtained by X-ray crystallography. 相似文献
44.
Chemical Fixation of CO2 and Other Heterogeneous Catalytic Studies by Employing a Layered Cu‐Porphyrin Prepared Through Single‐Crystal to Single‐Crystal Exchange of a Zn Analogue 下载免费PDF全文
A solvothermal reaction of Zn(NO3)2 ? 6 H2O, tetra‐(4‐pyridyl)porphyrin (H2TPyP), and 4,4′‐oxybis(benzoic acid) (H2OBA) resulted in a new two‐dimensional Zn‐ porphyrin metal–organic framework compound, [Zn2(C40H24N8)0.5(C14H8O5)(DMA)](DMA)(H2O)6 ( 1 ; DMA=N,N‐dimethylacetamide). The ZnII ions present in 1 could be exchanged by using a solution of Cu(NO3)2 ? 3 H2O in DMA at room temperature to give [Cu2(C40H24N8)0.5(C14H8O5)(DMA)](DMA)(H2O)3 ( Cu∈1 ). The extra‐framework solvent molecules have been shown to be reversibly removed or exchanged without collapse of the framework. Solvent‐free Cu∈1 was explored as an active heterogeneous catalyst towards three different organic reactions: 1) the chemical fixation of CO2 into cyclic carbonate at room temperature and 1 atm; 2) the nitroaldol reaction under solvent‐free conditions, and 3) the three‐component coupling of aminopyridine, benzaldehyde, and aryl alkynes followed by 5‐exo‐dig cyclization to produce the important pharmacophore imidazopyridine. 相似文献
45.
P. Vimalanathan S. P. Srinivasan V. Santhanam M. Rajesh 《International Journal of Polymer Analysis and Characterization》2018,23(2):99-112
Nowadays, the awareness of the public along with strict legitimate forces over the use of polymers, the manufacturing and automotive industries started using the renewable materials. Since, natural fiber reinforced composites play vital role in developing lightweight structural materials, this study focuses on utilizing sisal fiber as reinforcement in polyester matrix along with natural filler. The influence of fiber length and fiber volume fraction on the mechanical properties of sisal fiber was studied initially. Test results revealed that the composite with 20?mm fiber length and 20-volume fraction composite has better mechanical properties. Furthermore, the effect of fiber surface modification has been analyzed using various chemical solutions such as NaOH, KMnO4, stearic acid, and maleic acid. Of these, NaOH treatment enhances the mechanical properties of composite compared to all other cases. Finally, the influence of Acacia nilotica, a natural filler addition into the alkali-treated sisal fiber composite has been evaluated by mechanical and dynamic mechanical properties. It is found that the addition of natural filler and surface treatment has enhanced the properties of composites due to their synergetic effect. This effect improves the adhesion and uniform stress transfer among the reinforcements. The fiber surface morphology was evaluated using micrographs obtained from scanning electron microscope. 相似文献
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T. Ashok Reddy M. Srinivasan 《Journal of polymer science. Part A, Polymer chemistry》1987,25(11):2987-3003
Several polyesters containing thiaxanthone rings were prepared from 2,7-dichloroformylthiaxanthone-5,5′-dioxide ( IVa ), 2,8-dichloroformylthiaxanthone-5,5′-dioxide ( IVb ), and bisphenols by solution polycondensation. The 2,8-diethoxycarbonylthiaxanthone-5,5′-dioxide ( V ) was prepared and characterized by spectral methods to confirm the formation of 2,8-thiaxanthonedicarboxylic acid-5,5′-dioxide ( IVb ). Prior to polymer synthesis two model compounds,2,7-diphenoxycarbonylthiaxanthone-5,5′-dioxide (MDE-1) and 2,8-diphenoxycarbonylthiaxanthone-5,5′-dioxide (MDE-2), were synthesized and characterized by spectral methods. The polyesters were obtained in 62–78% yield and had inherent viscosities in the range 0.42–0.90 dL/g. The effect of thiaxanthone rings on solubility, crystallinity, and thermal stability of the polyesters are also discussed. The polyesters have decomposition temperatures in the range 372–438°C. 相似文献
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A Suresh Dinesh K Patre T G Srinivasan P R Vasudeva Rao 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2002,58(2):341-347
Spectrophotometric determination of microgram amounts of U(VI) with 2-(5-Bromo-2-Pyridylazo)-5-diethylaminophenol (Br-PADAP), originally developed by Johnson and Florence has been modified to enable the determination of U(VI) in the presence of a large excess of Th(IV). The effects of thorium, tri-n-butyl phosphate (TBP) and ethanol on the estimation of uranium have been studied in detail and are presented in this paper. This modified method can be applied for the analysis of U(VI) both in aqueous and organic samples containing a large excess of Th(IV) (Th:U = 10000:1). 相似文献