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451.
Chaitali De Rumpa Saha Sumanta K. Ghosh Aniruddha Ghosh Kakali Mukherjee Subhendu Sekhar Bhattacharyya Bidyut Saha 《Research on Chemical Intermediates》2013,39(8):3463-3474
The regioselective hydroformylation reactions of long chain olefins catalyzed by different unmodified and modified Co-based, Rh-based catalysts are summarized. The mechanism of homogeneous hydroformylation reactions using Co-based/Rh-based catalysts (unmodified) showed inhibition of reaction rate due to higher partial pressure of CO and also caused difficulty in separating catalysts from the product mixture. Hydroformylation reactions in biphasic medium using water soluble catalysts (Rh, Co, Ru/TPPTS) with an effective surfactant, cetyltrimethylammonium bromide (CTAB), are discussed. The homogeneous biphasic systems are not applicable for long chain olefins due to their low solubility in aqueous phase. 相似文献
452.
Kondapalli Venkata Gowri Chandra Sekhar Thripuraribhatla Venkata Naga Varuna Tara Sasank Hunsur Nagendra Nagesh Narva Suresh Kalaga Mahalakshmi Naidu Amaroju Suresh 《中国化学快报》2013,24(12):1045-1048
A simple and efficient method has been developed for conversion of chalcone oximes to 3,5-diaryl isoxazoles in excellent yields under solvent-free conditions. The synthesized compounds were characterized by infrared spectroscopy, ^1H NMR, ^13C NMR and HRMS. 相似文献
453.
Abstract
The Pictet–Spengler reaction, using polyethylene glycol immobilized tryptophan ester with a variety of ketones, was achieved by refluxing condition in acidic chloroform. The linear as well as cyclic ketones were employed. All the ketones were reacted within 6–8 h to furnish soluble polymer-supported tetrahydro-β-carboline in good yields. Further expansion at N-terminus of tetrahydro-β-carbolines was achieved through a reaction with chloroacetyl chloride. Finally, the 2,5-diketopiperazine skeleton was constructed over a β-carboline by amination of the resulting N-chloroacetamides and subsequent intramolecular cyclization leading to cleavage of the polymer; constitutes a traceless synthesis of tetracyclic molecular architecture. Significantly, this strategy affords a straightforward and efficient approach for the construction of biological promising molecules with high purity and good yields. 相似文献454.
The equations obtained by Yang while discussing the condition of self-duality of SU(2) gauge fields on Euclidean four-dimensional space have been generalized. Exact solutions and their graphical representations
for the generalized equation (for some particular values of the parameters) have been reported. They represent interesting
physical characteristics like waves with spreading solitary profile, spreading wave packets, waves with pulsating solitary
profile (between zero and a maximum), waves with oscillatory solitary profile and chaos.
相似文献
455.
456.
A steady state thermodynamic model for an air—cooled finned—tube condenser, used in a typical deep freezer vapour compression
system, operating with pure and refrigerant mixtures has been developed using finite difference method. The heat transfer
aspects in the condenser are treated uniquely for superheated, two—phase and subcooled regimes and studied for various heat
load, pressure, temperature, and mass flow rate. The condensation heat transfer coefficient, the tube length required for
condensation, the degree of subcooling, and the temperature glide for different ambient temperatures are estimated. The simulation
and the experimental results are in good agreement. 相似文献
457.
Saptarshi Roy Titas Chanda Tamoghna Das Aditi Sen Ujjwal Sen 《Physics letters. A》2018,382(26):1709-1715
We consider the scenario of deterministic classical information transmission between multiple senders and a single receiver, when they a priori share a multipartite quantum state – an attempt towards building a deterministic dense coding network. Specifically, we prove that in the case of two or three senders and a single receiver, generalized Greenberger–Horne–Zeilinger (gGHZ) states are not beneficial for sending classical information deterministically beyond the classical limit, except when the shared state is the GHZ state itself. On the other hand, three- and four-qubit generalized W (gW) states with specific parameters as well as the four-qubit Dicke states can provide a quantum advantage of sending the information in deterministic dense coding. Interestingly however, numerical simulations in the three-qubit scenario reveal that the percentage of states from the GHZ-class that are deterministic dense codeable is higher than that of states from the W-class. 相似文献
458.
In this paper, we concern about the Riemann problem for compressible no-slip drift-flux model which represents a system of quasi-linear partial differential equations derived by averaging the mass and momentum conservation laws with modified Chaplygin two-phase flows. We obtain the exact solution of Riemann problem by elaborately analyzing characteristic fields and discuss the elementary waves namely, shock wave, rarefaction wave and contact discontinuity wave. By employing the equality of pressure and velocity across the middle characteristic field, two nonlinear algebraic equations with two unknowns as gas density ahead and behind the middle wave are formed. The Newton–Raphson method of two variables is applied to find the unknowns with a series of initial data from the literature. Finally, the exact solution for the physical quantities such as gas density, liquid density, velocity, and pressure are illustrated graphically. 相似文献