نتایج جستجو برای: reusability of the catalyst
تعداد نتایج: 22795218 فیلتر نتایج به سال:
In this project various types of carbonyl compounds were efficiently converted to their corresponding 1,3-oxathiolanes with 2-mercaptoethanol in the presence of catalytic amount of Al-MCM-41 with microwave energy. The catalyst can be reused several times without loss of its catalytic activity. Very short reaction times, reusability of the catalyst, and easy workup are noteworthy advantages of ...
A heterogeneous catalyst containing manganese Schiff base complex (derived from 2,4-dihydroxybenzadehyde and 1,2-phenylenediamine) is produced by covalent anchoring in MCM-41 matrix. The synthesized catalyst was characterized by X-ray diffraction pattern (XRD), inductivity coupled plasma (ICP), Fourier transform infrared (FT-IR) spectroscopy, N2 sorbtion-desorbtion isotherm and by tr...
palladium is the best metal catalyst for suzuki cross coupling reaction for synthesize of unsymmetrical biaryl compounds. but its high cost limits its application in wide scale. using of nanoscale particles as active catalytic cites is a good approach for reducing needed noble metal. by loading precious nanoparticles on magnetic nanocores as a support, recycling and reusing of catalyst will be ...
Phosphorus pentoxide used on alumina (P2O5/Al2O3) as an inexpensive, eco-friendly and non-toxic acid catalyst for the one-pot synthesis of 1,8-dioxo-octahydroxanthenes via multi-component reactions under solvent-free conditions. The present approach offers several advantages such as short reaction times, high yields, easy purification, recovery and reusability of the catalyst.
The preparation of bis-thiazolidinones has been achieved by a one-pot condensation reaction of araldehydes, ethylenediamine and thioglycolic acid in the presence of nano-CuCr2O4 nanoparticles under reflux conditions in toluene. This method provides several advantages including easy workup, excellent yields, short reaction times, reusability of the catalyst and low catalyst loading.
Synthesis of 2,4,5-triaryl-1H-imidazoles using a potent, green and reusable nano catalyst (FHS/SiO2)
A simple, green and efficient method for synthesis of 2,4,5-trisubstituted imidazoles is described via three-component cyclocondensation of benzil or benzoin, aldehyde and ammonium acetate by using the nano SiO2-supported ferric hydrogen sulfate (FHS/SiO2), as a catalyst, under solvent-free conditions. The nano SiO2 support and catalyst were characterized by X-ray diffraction (XRD), transmissio...
the utilization of hydroxy sodalite (h-sod) as catalyst under solvent-free condition is described for the efficient preparation of tetrahydrobenzo[b]pyrans. these compounds are synthesized by three-component reactions of aldehydes, alkylnitriles and dimedone. h-sod that is the waste-product of zeolite manufacturing process is used as an efficient and a very inexpensive catalyst. furthermore, it...
Ammonium monovanadate (NH4VO3) has been devoted as an efficient, commercially available, eco-friendly and reusable catalyst for the synthesis of bis(indolyl)methanes (BIMs), oxindole derivatives and also Michael adducts of indoles at 50 °C under solvent-free conditions. The reusability of this solid acid catalyst in addition with its selectivity has also been examined.
3,3,6,6-Tetramethyl-9-phenyl-3,4,6,7,9,10-hexahydroacridine-1,8-(2H,5H)-dione derivatives are synthesized by nano titanium dioxide as an efficient and reusable heterogeneous nano catalyst in a one pot multi component reaction. Easy preparation and separation of catalyst, simply workup procedure, clean reaction and reusability of the catalyst up to 7 times without appreciable loss of its catalyt...
chapter i provides an overview of structural linguistics and touches upon the saussurean dichotomies with the final goal of exploring their relevance to the stylistic studies of literature. to provide evidence for the singificance of the study, chapter ii deals with the controversial issue of linguistics and literature, and presents opposing views which, at the same time, have been central to t...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید