نتایج جستجو برای: solvent selectivity
تعداد نتایج: 99687 فیلتر نتایج به سال:
The combination of experimental data and results DFT calculations indicates that the catalytic activity chalconium halonium salts serving as sigma-hole donating organocatalysts cannot be clearly estimated via...
Solvents can significantly alter the rates and selectivity of liquid-phase organic reactions, often hindering the development of new synthetic routes or, if chosen wisely, facilitating routes by improving rates and selectivities. To address this challenge, a systematic methodology is proposed that quickly identifies improved reaction solvents by combining quantum mechanical computations of the ...
The formal [3 + 2]-photocycloaddition of 2-hydroxy- (2a) and 2-amino-1,4-naphthoquinone (2b) to olefins was studied in various solvents aiming at a possible enantioselective reaction course. The reaction conditions were optimised for irradiation at low temperature in a nonpolar solvent employing external fluorescent lamps as irradiation sources. Best yields for the reaction of 2-hydroxy-1,4-nap...
Flavonoids from Sophora flavescens were selectively extracted by mechanochemical-promoted extraction technology (MPET) after using response surface methodology to determine the optimal extraction parameters. The highest yield of 35.17 mg/g was achieved by grinding the roots with Na₂CO₃ (15%) at 440 rpm/min for 17.0 min and water was used as the sole solvent with a ratio of solvent to solid mate...
• Solvent polarity index and hydrogen uptake influence conversion selectivity. Pd/C PdRh/Al 2 O 3 showed excellent stability after three cycles of experiments. Orders effect catalyst process parameters are summarised as follows. Creosol Selectivity: >> Rh/Al Pt/SiO > Pd/Al Pt/C. Degree deoxygenation: loading temperature pressure agitation. This study reports mild hydrodeoxygenation (HDO) vanill...
Owing to their fundamental importance and practical applications, anatase TiO2 crystals with well-defined {001} and {101} facets attracted intensive research interests. In this study, we systematically investigated solvent dependence of the photoreaction of the different coexposed crystal facets during noble metal photodeposition. By examining the deposition position in each solvent, we reveale...
Cholesteric elastomers possess a macroscopic "phase chirality" as the director n rotates in a helical fashion along an optical axis z and can be described by a chiral order parameter alpha. This parameter can be tuned by changing the helix pitch p and the elastic properties of the network at formation. The cholesterics also possess a local nematic order, changing with temperature or during solv...
In the present study, the synthesis of diethylene triamine supported on cellulose biopolymer as a biodegradable solid basic heterogeneous catalyst was suggested. Then, the applicability of the synthesized catalyst cellulose bonded N-propyl diethylene triamine (CBPDETA) was tested for the synthesis of oxindole derivatives, an important class of potentially bioactive compounds. A various series o...
In the present study, the synthesis of diethylene triamine supported on cellulose biopolymer as a biodegradable solid basic heterogeneous catalyst was suggested. Then, the applicability of the synthesized catalyst cellulose bonded N-propyl diethylene triamine (CBPDETA) was tested for the synthesis of oxindole derivatives, an important class of potentially bioactive compounds. A various series o...
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