نتایج جستجو برای: heterogeneous catalyst

تعداد نتایج: 166602  

Soheil Sayyahi, Somayeh Heidari

Aromatic aldehydes are efficiently condensed with 2'-hydroxyacetophenone by polymer-supported basic ionic liquid as an excellent heterogeneous catalyst utilizing the Claisen–Schmidt reaction. Microwave irradiation has been employed, providing flavanone in good yield and short reaction time.

An environmentally benign procedure for the synthesis of vicinal nitrohydrins via the regioselective ring opening reaction of epoxides with nitrite anion using silica-bound 3-{2-[poly(ethylene glycol)]ethyl}-substituted 1-methyl-1H-imidazol-3-ium bromide as an effective heterogeneous phase transfer catalyst was described. Short reaction time, high yield of products, simple work-up proc...

A novel magnetite nanoparticle-based heterogeneous acidic catalyst [Fe3O4@SiO2@Am-PPC-SO3H] [HSO4] was successfully prepared and characterized by SEM, EDX, TGA, VSM and FT-IR techniques. The magnetically retrievable and sustainable catalyst was investigated in the reaction of aldehyde and o-aminophenol for the synthesis of benzoxazoles. The...

2016
Shouyun Cheng Lin Wei James Julson

The massive consumption of fossil fuels and associated environmental issues are leading to an increased interest in alternative resources such as biofuels. The renewable biofuels can be upgraded from bio-oils that are derived from biomass pyrolysis. Catalytic cracking and hydrodeoxygenation (HDO) are two of the most promising bio-oil upgrading processes for biofuel production. Heterogeneous cat...

Ali Reza Kiasat Fatemeh Mohammad-Taheri Maryam Zayadi Mehdi Fallah-Mehrjard

Polyethylene glycol was easily grafted to silica gel and used as a solid–liquid phase transfer catalyst in the reduction of aromatic nitro compounds. This silica-grafted polyethylene glycol is proved to be an efficient heterogeneous catalyst in the reduction of nitroarenes to the corresponding aromatic amines with zinc powder in water. The reduction reactions proceeded efficiently with exce...

Soheil Sayyahi, Somayeh Heidari

Aromatic aldehydes are efficiently condensed with 2'-hydroxyacetophenone by polymer-supported basic ionic liquid as an excellent heterogeneous catalyst utilizing the Claisen–Schmidt reaction. Microwave irradiation has been employed, providing flavanone in good yield and short reaction time.

Dariush Saberi Farid Rohandeh Khodabakhsh Niknam

Sulfuric acid ([3-(3-silicapropyl)sulfanyl]propyl]ester (SASPSPE) is employed as a recyclable catalyst for the silylation of hydroxyl groups. A good range of primary, secondary alcohols and phenolic hydroxyl groups were effectively converted into their corresponding trimethylsilyl ethers with hexamethyldisilazane in the presence of catalytic amounts of SASPSPE at room temperature with short rea...

Rahimeh Hajinasiri, Saeid Afshari-sharifabad Saman Rezayati Sobhan Rezayati Zahra Erfani,

An efficient and simple procedure for the synthesis of 1,8-dioxo-octahydroxanthenes from the aromatic aldehydes and 5,5-dimethylcyclohexane-1,3-dione (dimedone) in the presence of boric acid [BO3H3 or B(OH)3] as an inexpensive and reusable catalyst is described. The salient features of this methodology are: the elimination of corrosive liquid acids, high yields, simple methodology, short reacti...

Journal: :Angewandte Chemie 2014
Fan Shi Aaron M Coffey Kevin W Waddell Eduard Y Chekmenev Boyd M Goodson

A novel variant of an iridium-based organometallic catalyst was synthesized and used to enhance the NMR signals of pyridine in a heterogeneous phase by immobilization on polymer microbead solid supports. Upon administration of parahydrogen (pH2) gas to a methanol mixture containing the HET-SABRE catalyst particles and the pyridine, up to fivefold enhancements were observed in the (1)H NMR spect...

2015
Oleg G. Salnikov Kirill V. Kovtunov Igor V. Koptyug

An experimental approach for the production of catalyst-free hyperpolarised ethanol solution in water via heterogeneous hydrogenation of vinyl acetate with parahydrogen and the subsequent hydrolysis of ethyl acetate was demonstrated. For an efficient hydrogenation, liquid vinyl acetate was transferred to the gas phase by parahydrogen bubbling and almost completely converted to ethyl acetate wit...

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