نتایج جستجو برای: functionalized silica catalyst

تعداد نتایج: 99021  

2017
Marco T Sabatini Lee T Boulton Tom D Sheppard

Chemical reactions for the formation of amide bonds are among the most commonly used transformations in organic chemistry, yet they are often highly inefficient. A novel protocol for amidation using a simple borate ester catalyst is reported. The process presents significant improvements over other catalytic amidation methods in terms of efficiency and safety, with an unprecedented substrate sc...

2014
Wei Jie Ang Chih-Hsuan Tai Lee-Chiang Lo Yulin Lam

Annulation of internal alkynes with functionalized aryl halides is a versatile and useful method for the synthesis of a wide variety of carboand heterocycles (Fig. 1). To date, many homogeneous transition metal-based catalytic systems have been developed for this transformation. Although homogeneous catalysis have many advantages, difficulties in separation and recovery of the catalyst and prod...

Journal: :ACS applied materials & interfaces 2010
Wassana Yantasee Ryan D Rutledge Wilaiwan Chouyyok Vichaya Sukwarotwat Galya Orr Cynthia L Warner Marvin G Warner Glen E Fryxell Robert J Wiacek Charles Timchalk R Shane Addleman

Surface-functionalized nanoporous silica, often referred to as self-assembled monolayers on mesoporous supports (SAMMS), has previously demonstrated the ability to serve as very effective heavy metal sorbents in a range of aquatic and environmental systems, suggesting that they may be advantageously utilized for biomedical applications such as chelation therapy. Herein we evaluate surface chemi...

Journal: Journal of Nanoanalysis 2017
Ali Reza Kiasat Jamal Davarpanah,

In the present study, application of porous acidic catalyst functionalized with an imidazoleionic liquid ([SBA-Im]HSO4) as a phase transfer catalyst for the facile preparation of benzylthiocyanates and azides in water has been described. The catalyst has been characterized byFourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), transmissionelectron microscopy (TEM...

Journal: :journal of sciences, islamic republic of iran 2015
s. ghasemi b. tamami r. teymoori h. allahyari

poly (vinylpyrrolidone)-grafted silica as an organic-inorganic hybrid material was used as an effective heterogeneous polymeric cosolvent catalyst in organic reactions. this modified silica catalyzed nucleophilic displacement of alkyl halides for easy preparation of alkyl thiocyanates, alkyl cyanides, alkyl azides and alkyl aryl ethers. furthermore, the catalyst was applied for the conversion o...

Journal: :Langmuir : the ACS journal of surfaces and colloids 2010
Yan Wu Sambit Misra M Basar Karacor Shaurya Prakash Mark A Shannon

The dynamic response of an oscillating microcantilever with a gold-coated tip interacting with dissimilar functionalized silica surfaces was studied in electrolyte solutions with pH ranging from 4 to 9. Silica surfaces were chemically modified, yielding dissimilar surfaces with -Br, -NH(2), and -CH(3) functional group terminations. The relative hydrophobicity of the surfaces was characterized b...

2016
Haruka Yamaguchi Makoto Tsuchimochi Kazuhide Hayama Tomoyuki Kawase Norio Tsubokawa

We sought to develop dual-modality imaging probes using functionalized silica nanoparticles to target human epidermal growth factor receptor 2 (HER2)-overexpressing breast cancer cells and achieve efficient target imaging of HER2-expressing tumors. Polyamidoamine-based functionalized silica nanoparticles (PCSNs) for multimodal imaging were synthesized with near-infrared (NIR) fluorescence (indo...

2001
G. Romanelli H. Thomas

Deprotection of various phenols from their respective methoxymethyl ethers using an heteropolyacid catalyst was studied. The catalyst was the Wells-Dawson heteropolyacid, used both in bulk or supported on silica. Yields were high to quantitative after less than one hour reaction time and the catalyst was easily recoverable and reusable.

Journal: :Chemical communications 2010
Chin-Keng Chen Yan-Wun Chen Che-Hung Lin Hong-Ping Lin Chin-Fa Lee

Novel CuO on mesoporous silica is prepared under a convenient approach, and has been shown to be an efficient catalyst for cross-coupling reactions of thiols with aryl iodides with only 1.0-5.0 mol% catalyst loading.

Journal: :Chemical communications 2013
Hongdeng Qiu Shengxiang Jiang Makoto Takafuji Hirotaka Ihara

New polyanionic and polyzwitterionic azobenzene ionic liquid-functionalized silica materials were designed based on the preparation of a new polymerizable azobenzene anionic monomer and either its cation-exchange with alkylimidazolium after grafting or the formation of an ionic liquid monomer pair before grafting onto silica.

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