نتایج جستجو برای: acidic catalyst
تعداد نتایج: 77393 فیلتر نتایج به سال:
A novel Brönsted-Lewis acidic heteropoly organic-inorganic salt has been prepared via the replacement of protons in neat phosphotungstic acid with both organic and metal cations. This hybrid catalyst, Sm0.33[TEAPS]2PW12O40, exhibited satisfactory performance in the dimerization of rosin to prepare polymerized rosin Under optimum conditions (15.0 g rosin and 5.0 g Sm0.33[TEAPS]2PW12O40 catalyst ...
An efficient synthesis of novel 3,4-dihydropyrimidin-2(1H)-ones (DHPMs) and their derivatives, using Brønsted acidic ionic liquid [C₂O₂BBTA][TFA] as a catalyst, from the condensation of aryl aldehyde, β-ketoester and urea was described. Reactions proceeded smoothly for 40 min under solvent-free conditions and gave the desirable products with good to excellent yields (up to 99%). The catalyst co...
the silica boron sulfuric acid nanoparticles (sbsans) as an efficient heterogeneous solid acid catalyst with both brønsted and lewis acidic sites catalyzed the preparation of bis-4-hydroxycoumarin derivatives using reaction of aldehydes and 4-hydroxycoumarin under mild and solvent-free condition at room temperature. this new and efficient methodology has advantages in comparison with currently ...
Pyrido[2,3-d]pyrimidine derivatives were synthesized regioselectivly in good to high yields by one-pot three-component condensation of 6-amino-2-(methylthio)pyrimidin-4(3H)-one, aromatic aldehydes and ethylcyanoacetate or meldrum's acid using 1,2-dimethyl-N-butanesulfonic acid imidazolium hydrogen sulfate ([DMBSI]HSO4) Brønsted-acidic ionic liquid as catalyst. Solvent-free mild reaction conditi...
A process was developed to synthesize ruthenium-based chelate RuNx electrocatalysts for the oxygen reduction reaction, using RuCl3 and propylene diammine as the Ru and N precursors, respectively. High-temperature pyrolysis has a critical role in the formation of the catalytic Ru–N sites for oxygen reduction. The RuNx catalyst modified in the presence of nitrogen-containing organic exhibited com...
Sulfonation of graphitic carbon nitride (g-CN) affords a polar and strongly acidic catalyst, Sg-CN, which displays unprecedented reactivity and selectivity in biodiesel synthesis and esterification reactions at room temperature.
A simple and environmentally benign procedure for the synthesis of 14-aryl-14H-dibenzo[a,j]xanthenes by a one-pot condensation of 2-naphthol with aromatic aldehyde in the presence of [Et3NH][HSO4] as an acidic ionic liquid catalyst under solvent-free conditions has been developed. The reaction work-up is very simple and the catalyst can be easily separated from the reaction mixture and reused s...
Polydispersed dinickel phosphide (Ni2P) nanoparticles were synthesized by a simple and scalable solid-state reaction. These nanoparticles are an excellent and robust catalyst for the electrochemical hydrogen evolution reaction, operating in both acidic and basic solutions.
Chiral trivalent phosphorus species are the dominant class of ligands and the key controlling element in asymmetric homogeneous transition-metal catalysis. Here, novel chiral diaminophosphine oxide ligands are described. The arising catalyst system with nickel(0) and trimethylaluminum efficiently activates formamide C-H bonds under mild conditions providing pyrrolidones via intramolecular hydro...
Improved catalytic durability towards acidic oxygen reduction reaction is achieved by using a Pt-free and Fe-free single-atom catalyst based on Mn, Co N co-doped carbon (MnCo–N–C), compared with (Co–N–C) catalyst.
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