نتایج جستجو برای: heterogeneous acid catalyst

تعداد نتایج: 901799  

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...

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 ...

A simple, efficient, and cost-effective procedure for the N-tert-butoxycarbonylation and N-formylation of amines (primary, secondary) respectively, with di-tert-butyl dicarbonate and 85% aqueous formic acid under solvent-free condition using B(OSO3H)3/SiO2 (SBSA) as a heterogeneous and recyclable catalyst has been developed. We demonstrated that the resulting catalyst is applicable to various a...

Kinetic Monte Carlo simulation was applied to investigation of kinetics and mechanism of oxalic acid degradation by direct and heterogeneous catalytic ozonation. La-containing perovskites including LaFeO3, LaNiO3, LaCoO3 and LaMnO3 was studied as catalyst for oxalic acid ozonation. The reaction kinetic mechanisms of each abovementioned catalytic systems has been achieved. The rate constants val...

Journal: :Molecules 2014
Manuela Oliverio Paola Costanzo Anastasia Macario Giuseppina De Luca Monica Nardi Antonio Procopio

Heterogeneous bifuctional catalysts are multifunctional synthetic catalysts enabling efficient organic transformations by exploiting two opposite functionalities without mutual destruction. In this paper we report the first Er(III)-based metallorganic heterogeneous catalyst, synthesized by post-calcination MW-assisted grafting and modification of the natural aminoacid L-cysteine. The natural ac...

Journal: :Chemical & pharmaceutical bulletin 2008
Biswanath Das Martha Krishnaiah Keetha Laxminarayana Duddukuri Nandankumar

Silica supported phosphomolybdic acid, an eco-friendly heterogeneous catalyst, has been found to be highly efficient for Friedlander synthesis of quinolines in excellent yields. A variety of ketones afford the quinolines smoothly. The catalyst can be easily recovered and reused.

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه کاشان - دانشکده علوم 1384

فن آوری های کاتالیتیکی نقش مهمی را در گسترش اقتصاد صنعت شیمیایی در قرن بیستم ایفا می کنند. امروزه فرایندهایی که به صورت هیدروژن کاتالیز می شوند به عنوان روش های عملی و تجربی ساده، فوایدی زیادی نظیر شرایط واکنش ملایم و اتلاف پایین دارند. یکی از این فرآیندها واکنش نیتروزدار کردن برای تولید n- نیتروز آمین هاست که توجه قابل ملاحظه ای را در سال های اخیر به خاطر خواص سرطان زایی شدید خود جلب کرده ان...

Journal: :iranian journal of catalysis 2012
farhad shirini somayeh sarvi beigbaghlou seyyed vahid atghia

various types of aldehydes undergo crossed-aldol condensation with ketones in the presence of melamine trisulfonic acid (mtsa) under solvent-free conditions. the reported method is mild, efficient and has the advantages such as using heterogeneous catalysis, short reaction times, high yields of the products and the recyclability of the catalyst.

Journal: :iranian journal of catalysis 2015
batol zakerinasab mohammad ali nasseri ali allahresani

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...

Journal: :iranian journal of catalysis 2013
srinivasa rao jetti divya verma shubha jain

decatungstodivanadogermanic acid (h6gew10v2o40.22h2o) was used as a green heterogeneous catalyst for the synthesis of 3,4-dihydropyrimidin-2-(1h)-ones from one-pot three-component cyclocondensation reaction of a β-ketoester, an aldehyde and urea/thiourea under solvent-free conditions is reported. this method provides an efficient and much improved modification of the original biginelli reaction...

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