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1.
Rate constants for the reaction of ethyl bromoacetate with three series of substituted naphthoate ions have been measured
in an acetone-water mixture (90% v/v). Using σ
p
values rate constants at 30o correlate well with the Hammett equation yielding ρ=−0.54, −0.19 and −0.25 for (4,1−), (6,1−) and (6,2−) series, respectively.
Comparison of these ρ values with those of the reaction of phenacyl bromide reveals the failure of the reactivity-selectivity
principle RSP in these reactions. Failure of RSP has been explained in terms of isoselective temperature. 相似文献
2.
Chilakapati Venkata Vishnu Vardhan Sajal Ghosh Subramaniam Nagaraj Raghavachary Sridharan Thiagarajan Gnanasekaran 《Journal of Thermal Analysis and Calorimetry》2013,112(1):127-131
A study of binary, CaBr2–CaHBr system was carried out by differential thermal analysis (DTA), covering the composition range from 100 % CaBr2 to 100 % CaHBr between room temperature and 800 °C. From DTA results, the contour of solidus and liquidus temperatures with composition is plotted and the phase diagram of CaBr2–CaHBr system is constructed. The system shows an eutectic reaction at 576 °C and the eutectic composition is 79.6 mol% CaBr2. Co-existing phases in different phase fields are characterized by X-ray diffraction analysis. 相似文献
3.
4.
Sulata Kumari Sahu Rajesh Ganesan T. Gnanasekaran 《The Journal of chemical thermodynamics》2010,42(1):1-7
Standard molar Gibbs free energy of formation of ternary oxides Pb5CrO8(s), Pb2CrO5(s), and PbCrO4(s) were determined by measuring equilibrium oxygen partial pressures over relevant phase fields using manometry and solid oxide electrolyte based emf methods and are given by: 相似文献
5.
Balu Devipriya Azhagesan Renuga Parameswari Gnanasekaran Rajalakshmi Poomani Kumaradhas 《International journal of quantum chemistry》2012,112(4):1185-1197
A Charge density analysis of CTB molecule in gas phase (Form I ) and the same present at the active site (Form II ) of p300 enzyme were performed for the wave functions obtained from the Density functional method (B3LYP) with the basis set 6‐311G**. This study has been carried out to understand the nature of conformational modification, charge redistribution and the change of electrostatic moments of the CTB molecule when present at the active site of p300. The difference of charge density distribution between both forms of CTB molecule explicitly indicates the effect of intermolecular interaction on CTB molecule in the active site. The dipole moment of CTB in the gas phase (9.6 D) has been significantly decreased (4.27 D) when it present at the active site of p300; this large variation is attributed to the charge redistribution in CTB, due to the intermolecular interaction between the CTB and the receptor p300 molecule. The electrostatic potential maps differentiate the difference of electrostatic potential between the two forms. A large electronegative region is found at the vicinity of oxygen and fluorine atoms. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012 相似文献
6.
A. Sree Rama Murthy Dhruv Pathak Gautam Sharma K.I. Gnanasekar V. Jayaraman A.M. Umarji T. Gnanasekaran 《Analytica chimica acta》2015
The transient changes in resistances of Cr0.8Fe0.2NbO4 thick film sensors towards specified concentrations of H2, NH3, acetonitrile, acetone, alcohol, cyclohexane and petroleum gas at different operating temperatures were recorded. The analyte-specific characteristics such as slopes of the response and retrace curves, area under the curve and sensitivity deduced from the transient curve of the respective analyte gas have been used to construct a data matrix. Principal component analysis (PCA) was applied to this data and the score plot was obtained. Distinguishing one reducing gas from the other is demonstrated based on this approach, which otherwise is not possible by measuring relative changes in conductivity. This methodology is extended for three Cr0.8Fe0.2NbO4 thick film sensor array operated at different temperatures. 相似文献
7.
A new synthesis of 2,3-dialkyl-4-carbomethoxyisoquinolin-1(2H)-ones and 6,7-dialkyl-8-carbomethoxy-1,6-naphthyridin-5(6H)-ones is reported. The process involves treatment of a β-enaminoester with 2-fluoro-5-nitrobenzoyl chloride, 2-fluorobenzoyl chloride or 2-chloronicotinoyl chloride followed by heating in the presence of base. The conversion, which proceeds by an N-acylation-SNAr reaction sequence, affords 50–86% yields when R1 is n-alkyl but ≤30% yields when R1 is α-branched. 相似文献
8.
Sulata K. Sahu Manjulata Sahu Raman S. Srinivasa Thiagarajan Gnanasekaran 《Monatshefte für Chemie / Chemical Monthly》2012,97(3):1207-1214
Abstract
Heat capacities of PbCrO4(s), Pb2CrO5(s), and Pb5CrO8(s) were measured by differential scanning calorimetry. The measured heat capacities as a function of temperature are expressed as C p <PbCrO4> J K−1 mol−1 = 150.37 + 27.74 × 10−3 T − 2.80 × 106 T −2 (T = 300–750 K), C p <Pb2CrO5> J K−1 mol−1 = 194.55 + 76.09 × 10−3 T − 4.64 × 106 T −2 (T = 300–700 K), and C p <Pb5CrO8> J K−1 mol−1 = 323.35 + 184.80 × 10−3 T − 5.48 × 106 T −2 (T = 300–600 K). From the measured heat capacity data, thermodynamic functions such as enthalpy increments, entropies, and Gibbs energy functions were derived. 相似文献9.
Lanthanum fluoride thin film has been deposited on glass substrates by PVD method at various deposition temperatures (Ts), viz, 300, 473, 573 and 673 K. The hexagonal phase LaF3 film has been detected by using glancing angle XRD analysis. The structural parameters such as lattice constants, grain size and micro-strain has been calculated from the XRD data. The F− ion conduction through the grain and grain boundary has been analyzed using impedance analysis. The modulus spectra reveals the non-Debye nature and the distribution of relaxation times of the film. 相似文献
10.
Electrical and gas sensing properties of Ag6Mo10O33 are investigated for the first time. Wagner’s polarization experiment carried out on this material shows that it is a good
silver ion conductor in the temperature range of 533 to 657 K. Studies show that it possesses good selectivity and sensitivity
towards ammonia with fast response and retrac times indicating its potential as a sensor material for this gas below its TLV
value. Morphological changes associated with this compound when exposed to ammonia are studied by using SEM and the corresponding
compositional changes associated with each grain is studied by using EDAX. The results indicate that the compound breaks down
when exposed to ammonia. When equilibrated with air the reaction products recombine fast to form the original compound.
Paper presented at the 2nd International Conference on Ionic Devices, Anna University, India, Nov. 28–30, 2003. 相似文献