An Efficient Electrophilic N-Amination Utilizing in situ Generated Chloramine under Phase Transfer Conditions.

ChemInform ◽  
2006 ◽  
Vol 37 (45) ◽  
Author(s):  
Apurba Bhattacharya ◽  
Nitin C. Patel ◽  
Robert Erik Plata ◽  
Michael Peddicord ◽  
Qingmei Ye ◽  
...  
Keyword(s):  
Phase Transfer

Microwave Energy Pretreated In Situ Transesterification of Jatropha Curcas L in the Presence of Phase Transfer Catalyst

2014 ◽  
Vol 625 ◽  
pp. 267-270 ◽  
Author(s):  
Sintayehu Mekuria Hailegiorgis ◽  
Mahadzir Shuhaimi ◽  
Duvvuri Subbarao
Keyword(s):  
Statistical Model ◽  
Jatropha Curcas ◽  
Phase Transfer ◽  
Phase Transfer Catalyst ◽  
In Situ Transesterification ◽  
Heat Pretreatment ◽  
Seed Particles ◽  
Optimum Reaction ◽  
Microwave Heat

In the present work, microwave heat pretreatment of jatropha curcas seed particles and use of phase transfer catalyst (PTC) to enhance in-situ transesterification were utilized together. It was observed that use of alkaline BTMAOH as a PTC and microwave heat pretreatment of jatropha curcas seed particles had substantially increased the reaction rate of in-situ transesterification as compared to the reaction conducted with microwave untreated seeds in the absence of BTMAOH as a PTC. Statistical model equation was developed to investigate the interaction effect of reaction variables and establish optimum reaction condition. At optimum condition, experimentally obtained FAME yield (93.7±1.53% w/w) was in close agreement with statistical model predicted FAME yield (96.75%) at 38°C and 37 minutes of reaction time.

Phase-Transfer-Catalyzed Asymmetric Aza-Henry Reaction UsingN-Carbamoyl Imines Generated In Situ from α-Amido Sulfones

2005 ◽  
Vol 44 (48) ◽  
pp. 7975-7978 ◽  
Author(s):  
Francesco Fini ◽  
Valentina Sgarzani ◽  
Daniel Pettersen ◽  
Raquel P. Herrera ◽  
Luca Bernardi ◽  
...  
Keyword(s):  
Phase Transfer ◽  
Henry Reaction

scholarly journals In Situ Electrophilic Activation of Hydrogen Peroxide for Catalytic Asymmetric α-Hydroxylation of 3-Substituted Oxindoles

Synlett ◽  
2017 ◽  
Vol 28 (11) ◽  
pp. 1291-1294 ◽  
Author(s):  
Takashi Ooi ◽  
Kohsuke Ohmatsu ◽  
Yuichiro Ando
Keyword(s):  
Hydrogen Peroxide ◽  
Phase Transfer ◽  
Practical Method ◽  
Optically Active ◽  
Aqueous Hydrogen Peroxide ◽  
Bond Forming ◽  
Electrophilic Activation ◽  
Oxygen Bond ◽  
Activation Of Hydrogen Peroxide

Peroxy trichloroacetimidic acid, in situ generated from aqueous hydrogen peroxide and trichloroacetonitrile, was found to act as a competent electrophilic oxygenating agent for the direct α-hydroxylation of oxindoles. The use of chiral 1,2,3-triazolium salt as a phase-transfer catalyst enabled rigorous absolute stereocontrol in the carbon–oxygen bond-forming reaction. The present study provides a new, yet practical method for straightforward access to optically active α-hydroxycarbonyl compounds.

Real neutralization reactions of amines against ammonia by acids in ambient air

2020 ◽  
Author(s):  
Dihui Chen ◽  
Yujiao Zhu ◽  
Yanjie Shen ◽  
Xiaohong Yao
Keyword(s):  
Phase Transfer ◽  
Common Knowledge ◽  
Ambient Air ◽  
Acid Vapor ◽  
Concept Model ◽  
New Findings ◽  
Cooling Effects ◽  
In Situ Observations ◽  
The Common

<p>Amines reportedly overwhelm ammonia in generating new particles through neutralizing sulfuric acid vapor even with several orders smaller concentrations of amines against ammonia in ambient air, demonstrating an attractive prospect in adjusting concentrations of amines to adjust aerosol number loadings, alleviate air pollution and manipulate aerosol cooling effects. Due to lack of in-situ observations, real competition of amines against ammonia in ambient air to be neutralized by acids remains poorly understood. Here, successful semi-continuous measurements of gaseous amines and ammonia and their particulate partners in marine atmospheres reveal that atmospheric trimethylamine (TMA<sub>gas</sub>) unable to compete with NH<sub>3gas</sub> and to form particulate trimethylaminium (TMAH<sup>+</sup>), but the particulate TMA (TMA<sub>particulate</sub>) is detectable and comparable to TMA<sub>gas</sub> under NH<sub>3gas</sub> <1.0 µg m<sup>-3</sup>. Contradictory to the common knowledge, the preexisting TMA<sub>particulate</sub> is largely depleted in strong SO<sub>2</sub> plumes with abundant acids and even depleted NH<sub>3gas</sub>. A two-aerosol-phase transfer concept model is proposed to interpret the new findings, but no single-phase acid-base neutralization reactions can. In contrast, observational evidences confirm that gaseous dimethylamine (DMA<sub>gas</sub>) plus particulate dimethylaminium (DMAH<sup>+</sup>) overwhelmingly exist as DMAH<sup>+</sup> under atmospheric NH<sub>3</sub> (NH<sub>3gas</sub>) <0.3 µg m<sup>-3</sup> versus DMA<sub>gas</sub> under NH<sub>3gas</sub> >1.8 µg m<sup>-3</sup>, respectively. The neutralization of DMA<sub>gas</sub> to form DMAH<sup>+ </sup>is always enhanced in strong SO<sub>2 </sub>plumes, almost independent on NH<sub>3gas</sub>. Thermodynamically, DMA<sub>gas</sub> may act as a competitor in generating secondary particles only under low NH<sub>3gas</sub> or in SO<sub>2</sub> plumes.</p>

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