نتایج جستجو برای: catalyst reusability
تعداد نتایج: 48764 فیلتر نتایج به سال:
The surface of magnetite nanoparticles as nano-sized solid support was modified with a molybdenum-Schiff base complex to prepare an easily separable heterogeneous catalyst for the epoxidation of olefins. Characterization techniques such as Fourier transform infrared and inductively coupled plasma optical emission spectroscopies, X-ray diffraction, vibrating sample magnetometry, scanning, an...
In this paper, an environmentally benign access to synthesize Bis(pyrazol-5-ol) derivatives was developed through the one pot pseudo five component condensation reaction of phenyl hydrazine with ethyl acetoacetate, and different aryl/heteroaryl aldehydes using morpholinium glycolate as the homogeneous reusable catalyst under solvent-free conditions at 80 °C. Further, the ionic liquid was prepar...
Sulfonic acid functionalized nanoporous silica (SBA-Pr-SO3H) with a pore size of 6 nm catalyzed three component coupling of aromatic aldehydes, urea and ethyl acetoacetate to afford the corresponding dihydropyrimidinones under solvent free condition. This new protocol for Biginelli reaction has important advantages such as green synthesis, short reaction time, easy isolation and high yields of ...
In this paper, an environmentally benign access to synthesize Bis(pyrazol-5-ol) derivatives was developed through the one pot pseudo five component condensation reaction of phenyl hydrazine with ethyl acetoacetate, and different aryl/heteroaryl aldehydes using morpholinium glycolate as the homogeneous reusable catalyst under solvent-free conditions at 80 °C. Further, the ionic liquid was prepar...
This article describe the applicability of 1,4-disulfopiperazine-1,4-diium chloride ([Piper-(SO3H)2].2Cl) as a green, versatile and Brönsted acidic ionic catalyst in the promotion of the synthesis of phthalazine derivatives via one-pot three component reaction between aromatic aldehydes, 1,3-diketone derivatives and phthalhydrazide under solvent-free reaction cond...
A simple and mild one-pot three-component reaction for the preparation 1,4-dihydropyridines has been developed from various aldehyde substrates, 1,3-dicarbonyl compounds (dimedone) and ammonium acetate (Hantzsch method) in the presence of a catalytic amount of phospho sulfonic acid (PSA) as an efficient and heterogeneous solid acid in EtOH at room temperature. Preparation of PSA is straightforw...
The Fe-MCM-22 zeolite was found to be an efficient solid heterogeneous catalyst for synthesis of dihydropyrano [2,3-c] pyrazoles via one pot four component reaction of ethyl acetoacetate, hydrazine hydrate, aromatic aldehyde and malononitrile in aqueous alcohol. The catalyst was synthesized by hydrothermal method under autogenous pressure and modified by Fe (III) ion exchange. The prepared cata...
The Fe-MCM-22 zeolite was found to be an efficient solid heterogeneous catalyst for synthesis of dihydropyrano [2,3-c] pyrazoles via one pot four component reaction of ethyl acetoacetate, hydrazine hydrate, aromatic aldehyde and malononitrile in aqueous alcohol. The catalyst was synthesized by hydrothermal method under autogenous pressure and modified by Fe (III) ion exchange. The prepared cata...
The use of metal co-catalysts broadens the application of photocatalytic reduction without the use of dihydrogen (H2) gas. We examined photocatalytic hydrogenation of furan, a representative heterocyclic compound and a compound derived from biomass, in alcoholic suspensions of metal-loaded titanium(iv) oxide (TiO2) under a H2-free condition and we found that furan was almost quantitatively hydr...
A Periodic Mesoporous Organosilica (PMO) functionalized with sulfonic acid groups has been successfully synthesized via a sequence of post-synthetic modification steps of a trans-ethenylene bridged PMO material. The double bond is functionalized via a bromination and subsequent substitution obtaining a thiol functionality. This is followed by an oxidation towards a sulfonic acid group. After fu...
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