نتایج جستجو برای: Silica gel, Water, Aldehyde

تعداد نتایج: 688621  

Journal: :iranian journal of catalysis 2013
saeed khodabakhshi mojtaba baghernejad

silica gel has been used for synthesis of biscoumarin derivatives starting from 4-hydroxycoumarin and aryl aldehydes. the reaction conditions are completely in agreement with green chemistry principles including sing water as media and a recyclable and safe catalyst. this method is also simple and inexpensive and leads to high yield of products in short reaction times.

Journal: :Molecules 2012
Nina Melnikova Irina Burlova Tatiana Kiseleva Irina Klabukova Marina Gulenova Capital A Cyrillicleksey Kislitsin Viktor Vasin Boris Tanaseichuk

The room temperature oxidation of betulin by Cr(VI) compounds in aqueous acetone on solid supports such as alumina, zeolites and silica gel has been studied. The oxidation on alumina support leaded to a single product--betulonic acid--in quantitative yield. One hundred percent selective oxidation during 30 min of betulin up to betulonic aldehyde was determined when silica gel support was used. ...

Mojtaba Baghernejad Saeed Khodabakhshi,

Silica gel has been used for synthesis of biscoumarin derivatives starting from 4-hydroxycoumarin and aryl aldehydes. The reaction conditions are completely in agreement with green chemistry principles including sing water as media and a recyclable and safe catalyst. This method is also simple and inexpensive and leads to high yield of products in short reaction times.

Mojtaba Baghernejad Saeed Khodabakhshi,

Silica gel has been used for synthesis of biscoumarin derivatives starting from 4-hydroxycoumarin and aryl aldehydes. The reaction conditions are completely in agreement with green chemistry principles including sing water as media and a recyclable and safe catalyst. This method is also simple and inexpensive and leads to high yield of products in short reaction times.

2015
Ahmed Rezk Raya Al-Dadah Saad Mahmoud Ahmed Elsayed

Silica gel/water adsorption cooling systems suffer from size, performance and cost limitations. Therefore, there is a need for new adsorbent materials that outperform silica gel. Metal organic frameworks (MOFs) are newmicro-porousmaterials that have extraordinary porosity and uniform structure. Due to the lack of published data that characterise MOF/water adsorption, this paper experimentally i...

Journal: :Analytical sciences : the international journal of the Japan Society for Analytical Chemistry 2009
Kouta Nakada Imdad U Mohammadzai Satoshi Tsukahara Terufumi Fujiwara

The adsorption behavior of reverse micelles of cetyltrimethylammonium chloride (CTAC) onto porous silica gels of various pore sizes has been investigated. A decrease in the amount of CTAC in the reversed micellar bulk solution in chloroform/water added to the silica gel in a column was observed, indicating the CTAC adsorption onto the silica surface. The adsorption profile obtained showed a max...

2017
Sandra Rodrigues da Silva Nilson J A de Albuquerque Rusiene M de Almeida Fabiane C de Abreu

This study concerns the development and charaterization of Silica-based aldehyde Chitosan hybrid material as an adsorbent for biodiesel purification. This biocomposite was prepared by sol-gel route and oxidation with periodate, and then characterized. FTIR experiments showed that the hybrid formed presents absorption bands similar to those of Chitosan-Silica, with the exception of the vibration...

Journal: :Applied Biological Chemistry 2021

Abstract Cnidium officinalis rhizomes were immersed in 80% MeOH. The extract was fractionated to water, n -butanol, and ethyl acetate fractions (Fr). Open column chromatography repeatedly carried out on n-butanol Fr using silica gel, octadecyl Sephadex LH-20 as the stationary phase affording five phenyl alkanoids 1 – 5 including two new ones. molecular structures stereochemistry decided based s...

Javad Safari, Simin Naseh Zahra Akbari Zohre Zarnegar

A simple highly versatile and efficient sonochemical synthesis of 1,2,4,5-tetrasubstituted and 2,4,5-trisubstituted imidazoles is achieved by condensation of 1,2-dicarbonyl compound, aldehyde, ammonium acetate and primary amine using antimony trichloride immobilized on silica gel (SiO2-OSbCl2) as a catalyst in ethanol at moderate temperature. Operational simplicity, practicability and applicabi...

Journal: :iranian journal of catalysis 2014
javad safari zohre zarnegar simin naseh zahra akbari

a simple highly versatile and efficient sonochemical synthesis of 1,2,4,5-tetrasubstituted and 2,4,5-trisubstituted imidazoles is achieved by condensation of 1,2-dicarbonyl compound, aldehyde, ammonium acetate and primary amine using antimony trichloride immobilized on silica gel (sio2-osbcl2) as a catalyst in ethanol at moderate temperature. operational simplicity, practicability and applicabi...

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