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71.
72.
Sujoy Biswas V. H. Rupawate S. B. Roy M. Sahu 《Journal of Radioanalytical and Nuclear Chemistry》2014,300(2):853-858
In this paper a quaternary ammonium based room temperature ionic liquid (IL) trioctylmethylammonium hydrogen phthalate has been reported as promising extractant for separation of U(VI) from other metal ions from aqueous media. The IL was synthesized via metathesis route and characterized using various techniques such as hydrogen nuclear magnetic resonance, electron spray ionization mass spectrometry and infra red etc. The newly synthesized IL was evaluated for extraction of U(VI), Th(IV), La(III), Y(III), Nd(III) and Fe(III) from aqueous solutions and follow the order: U(VI) > Th(IV) > Fe(III) > Y(III) >> Nd(III) ~ La(III). 相似文献
73.
S. N. Hardrict R. Gurarslan C. J. Galvin H. Gracz D. Roy B. S. Sumerlin J. Genzer A. E. Tonelli 《Journal of Polymer Science.Polymer Physics》2013,51(9):735-741
In this brief report, we demonstrate that Kerr effect measurements, which determine the excess birefringence contributed by polymer solutes in dilute solutions observed under a strong electric field, are highly sensitive to and capable of determining their microstructures, as well as their locations along the macromolecular backbone. Specifically, using atactic triblock copolymers with the same overall composition of styrene (S) and p-bromostyrene (pBrS) units, but with two different block arrangements, that is, pBrS90-b-S120-b-pBrS90 (I) and S60-b-pBrS180-b-S60 (II), which are indistinguishable by NMR, we detected a dramatic difference in their molar Kerr constants (mK), in agreement with those previously estimated. Although similar in magnitude, their Kerr constants differ in sign, with mK(II) positive and mK(I) negative. In addition, S/pBrS random and gradient copolymers synthesized by reversible addition-fragmentation chain-transfer (RAFT) polymerization exhibit a heretofore unexpected enhanced enchainment of racemic (r) pBrS-pBrS diads. Comparison of their observed and calculated mKs suggests that the gradient S/pBrS copolymers possess an unanticipated additional gradient in stereosequence that parallels their comonomer gradient, that is, as the concentration of pBrs units decreases from one end of the copolymer chain to the other, so does the content of r diads. This conclusion could only be reached by comparison of observed and calculated Kerr effects, which access the global properties of macromolecules, and not NMR, which is only sensitive to local polymer structural environments, but not to their locations on the copolymer chains. Molar Kerr constants are characteristic of entire polymer chains and are highly sensitive to their constituent microstructures and their distribution along the chain. They may be used to both identify constituent microstructures and locate them along the polymer chain, thereby enabling, for the first time, characterization of their complete macrostructures. © 2013 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2013 相似文献
74.
Debayan Roy Dr. Beeraiah Baire 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(12):4009-4015
Design and development of a domino cyclative approach for the synthesis of new polycyclic γ-butenolides from β-aryl-Z-enoate propargylic alcohols, through the interception of an intermediate of the Z-enoate-assisted Meyer–Schuster rearrangement, has been reported. A systematic NMR analysis of various derivatives of this class revealed and supported the potential atropisomerism associated with them. These molecules represent first examples of butenolide ring-based atropisomeric compounds in organic chemistry. The synthetic process involves a synchronous construction of both rings with concurrent creation of the potential stereogenic rotational axis. 相似文献
75.
2-Phenylquinoline derivatives have been synthesized through the thermolysis of suitable enaminoimine hydrochiorides. 相似文献
76.
R. G. Stebbins T. Roy T. R. Doane 《International journal of environmental analytical chemistry》2013,93(3):127-137
Abstract The 1-ethylmonocarboxylic acid of Malathion (MCA) was identified as a metabolite of Malathion in the gut of golden shiners (N. Chrysoleucas) (7.11 × 102±0.66 × 102 ng/g tissue). As noted in the literature the rate of hydrolysis of Malathion above pH 7 is first order with respect to Malathion and pH dependent. In addition, the rate of hydrolysis of Malathion in aquaria housing these fish was found to be dependent on the concentration of Ca+2; sparging the aquaria with air affected the rate. Some of the hydrolysis products of Malathion were identified by gc/ms and found to be pH dependent above pH 7. The half-life of Malathion under different conditions, the identification of some hydrolytic products and a general scheme for the analysis of Malathion, along with some of its metabolic and hydrolytic products are included in this paper. 相似文献
77.
Hydroxyl compounds readily add to dihydropyran in presence of a catalytic amount of ceric ammonium nitrate to give high yield of tetrahydropyranyl ethers. 相似文献
78.
79.
Rabindra N. Roy Lakshmi N. Roy Kathleen A. Allen Casey J. Mehrhoff Isaac B. Henson Jessica M. Stegner Alexis L. Jenkins Ankita A. Shah Stephen D. Rocchio 《Journal of solution chemistry》2012,41(6):1044-1053
In this study, we report the pH values of two buffer solutions without chloride ion and eight buffer solutions with NaCl with an ionic strength I=0.16 mol?kg?1. Electromotive force (emf) techniques have been used to get the cell potentials at 12 temperatures from 5 to 55?°C, including 37?°C. An extended form of the Bates-Guggenheim convention is used in the entire ionic strength range, 0.04 to 0.16?mol?kg?1. The residual liquid junction potentials (??E j ) of the buffer solutions of MOBS have been estimated from previous measurements with a flowing junction cell. These values of ??E j have been used for correction in order to ascertain the operational pH values of four buffer solutions of MOBS at 25 and 37?°C. These solutions are recommended as pH standards for physiological application in the pH range 7.4 to 7.7. 相似文献
80.
Experimental Techniques - One of the major sources of error in Atomic Force Microscopy based Force Spectroscopic studies is bottom substrate effect, which comes due to assumption of infinite sample... 相似文献