نتایج جستجو برای: lewis protic acid

تعداد نتایج: 762593  

2003
Franz Effenberger Matthias Seefelder

The most widely known electrophilic agents are protic acids and compounds with an electronsextet partial structure. Recent research has aimed at the development of new electrophilic reagents, with greater reactivity on the one hand and higher selectivity on the other, which would largely obviate the addition of Lewis acids (Friedel-Crafts catalysts), and also alIow control of the isomer ratio i...

2006
D. Bera D. Lahiri A. De Leonardis Antonella De Leonardis A. Nag

Hexane, the common solvent for extraction of edible oils from seeds is no more considered safe due to the presence of solvent in oil and also solvent vapour, a hazardous air pollutant. We have carried out the experiments with bahera (Terminalia bellerica Roxb) and flax seed (Linum usitatissimum ) oil as these oils are highly used in food for their nutraceutical values. The extraction of edible ...

Journal: :Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 2017

Journal: :Chemistry - An Asian Journal 2008

Journal: :Physical chemistry chemical physics : PCCP 2014
S Menne T Vogl A Balducci

The lithium ion-ion interactions in protic ionic liquids can be very different compared to those in aprotic ionic liquids. In this study we show that, for equal lithium ion concentration, the lithium coordination number in protic ionic liquids is lower than that in aprotic ones. This lower coordination makes lithium ions more "free" to move in protic ionic liquids and it might have an important...

Journal: :Physical chemistry chemical physics : PCCP 2017
Soumalya Mukherjee Edamana Prasad Anju Chadha

Bathochromic and hypsochromic shifts in the photo-luminescent spectra of doped and functionalized carbon nano-dots (CDs) arise due to the complex interaction between CDs and the solvent molecules around them. Nitrogen-functionalized carbon nano-dots (N-CDs) were synthesized from citric acid and urea using microwave assisted hydrothermal methods. Optical studies (absorption and photoluminescence...

Foad Buazar, Zohreh Dehghanizadeh

In this study, multi component Hantzsch reaction was carried out between various  Aromatic Aldehyde with Dimedone,Ethyl acetateand ammonium acetate to produce polyhydroquinolinederivatives under solvent-free conditions at 110oC by a (Zinc oxide  nanocatalyst) as effective Lewis acid. The remarkable advantages offered by this method compared with other methods are a green catalyst, simple work-u...

2015
Juho Bah Veluru Ramesh Naidu Johannes Teske Johan Franzén

One potential Lewis acid that has received negligible attention as a catalyst is the carbocation. Here we show the potential of triaryl methylium ions as highly powerful Lewis acid catalysts for organic reactions. The Lewis acidity of the triaryl methylium ion can be easily tuned by variation of the electronic properties of the aromatic rings and the catalytic activity of the carbocation is sho...

2014
Yasuhiro Yamashita Yuki Saito Takaki Imaizumi Shū Kobayashi

While Lewis acids andmetal amides are among themost frequently usedmetal species, they are believed to be incompatible when combined. Here we describe a Lewis acid/metal amide hybrid, which contains electron-withdrawing groups and basic and bulky nitrogen functional groups in the same metal complex, as a novel catalyst. We have synthesized In(N(SiMe3)2)2Cl (In(HMDS)2Cl) and In(HMDS)2OTf as Lewi...

Journal: :Chemistry 2014
Juho Bah Johan Franzén

In general, Lewis acid catalysts are metal-based compounds that owe their reactivity to a low-lying empty orbital. However, one potential Lewis acid that has received negligible attention as a catalyst is the carbocation. We have demonstrated the potential of the carbocation as a highly powerful Lewis acid catalyst for organic reactions. The stable and easily available triphenylmethyl (trityl) ...

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