In situ generated amine as a Lewis base catalyst in the reaction of 3,7‐dinitro‐1,3,5,7‐tetraazabicyclo[3.3.1]nonane in nitric acid: Experimental and DFT study

2019 ◽  
Vol 32 (8) ◽  
Author(s):  
Yu Zhang ◽  
Guoli Chi ◽  
Ying He ◽  
Zishuai Xu ◽  
Luyao Zhang ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Lewis Base ◽  
Dft Study ◽  
Base Catalyst

Synthesis of hydrosilanes via Lewis-base-catalysed reduction of alkoxy silanes with NaBH4

2019 ◽  
Vol 55 (42) ◽  
pp. 5859-5862 ◽  
Author(s):  
Keiya Aoyagi ◽  
Yu Ohmori ◽  
Koya Inomata ◽  
Kazuhiro Matsumoto ◽  
Shigeru Shimada ◽  
...  
Keyword(s):  
Lewis Base ◽  
Base Catalyst ◽  
Hexamethylphosphoric Triamide

Hydrosilanes were synthesized by reduction of alkoxysilanes with BH3 in the presence of hexamethylphosphoric triamide (HMPA) as a Lewis-base catalyst. The reaction was also achieved using an inexpensive and easy-to-handle handled hydride source NaBH4, which reacted with EtBr as a sacrificial reagent to form BH3in situ.

In situ phosphonium-containing Lewis base-catalyzed 1,6-cyanation reaction: facile way to α-diaryl and α-triaryl acetonitriles

2021 ◽  
Author(s):  
Jian-Ping Tan ◽  
Yuan Chen ◽  
Xiaoyu Ren ◽  
Yumeng Guo ◽  
Bing Yi ◽  
...  
Keyword(s):  
Butyl Acrylate ◽  
Lewis Base ◽  
Base Catalyst ◽  
Tert Butyl ◽  
Cyanation Reaction

Herein, we presente a phosphonium-containing catalyst generated in situ from phosphine and tert-butyl acrylate serves as an unusual Lewis base catalyst, and its successful application in promoting remote 1,6-cyanation reaction...

Formamide Catalysis Facilitates the Transformation of Aldehydes into Geminal Dichlorides

Synthesis ◽  
2019 ◽  
Vol 51 (12) ◽  
pp. 2474-2483 ◽  
Author(s):  
Peter Helmut Huy
Keyword(s):  
Nucleophilic Substitution ◽  
Substitution Reaction ◽  
Functional Group ◽  
Lewis Base ◽  
Base Catalyst ◽  
Reaction Conditions ◽  
Novel Method ◽  
In Situ Formation ◽  
Type Intermediate

Herein, a novel method for the transformation of aldehydes into geminal dichlorides based on phthaloyl chloride as reagent and N-formylpyrrolidine as Lewis base catalyst is disclosed. Given the mild reaction conditions, the current protocol is distinguished by high levels of functional group compatibility and scalability and is operationally simple. The in situ formation of a Vilsmeier Haack reagent type intermediate is likely to be essential for this organocatalytic nucleophilic substitution reaction.

[6 + 3] Annulations of Morita–Baylis–Hillman Carbonates and Dicyanoheptafulvene

2021 ◽  
Author(s):  
Yang Song ◽  
Ruo-Ling Jia ◽  
Shi Deng ◽  
Long-Wei Yang ◽  
Qing-Ling Liu
Keyword(s):  
Lewis Base ◽  
Base Catalyst

An [6 + 3] annulation reaction of Morita-Baylis-Hillman carbonates and dicyanoheptafulvene is accomplished by employing commercially available triphenylphosphine as the Lewis base catalyst. A spectrum of densely functionalized bicyclo[4.3.1]decane architectures...

scholarly journals Technical Note: Evaporation of polar stratospheric cloud particles, in situ, in a heated inlet

2005 ◽  
Vol 5 (1) ◽  
pp. 97-106 ◽  
Author(s):  
T. Eidhammer ◽  
T. Deshler
Keyword(s):  
Particle Size ◽  
Nitric Acid ◽  
Size Distribution ◽  
Technical Note ◽  
Ternary Solution ◽  
Slow Evaporation ◽  
Partial Pressures ◽  
Polar Stratospheric Cloud ◽  
Stratospheric Clouds

Abstract. In December 2001 and 2002 in situ aerosol measurements were made from balloon-borne platforms within polar stratospheric clouds (PSC) which contained particles of supercooled ternary solution (STS), nitric acid trihydrate (NAT) and ice. Particle size and number concentrations were measured with two optical particle counters. One of these included an ~80cm inlet heated to K to evaporate the PSC particles and thus to obtain measurements, within PSCs, of the size distribution of the particles upon which the PSCs condensed. These measurements are compared to models, described here, that calculate the evaporation of PSC particles at and for an inlet transition time of about 0.1s. The modeled evaporation for STS agrees well with the measurements. For NAT the modeled evaporation is less than the evaporation measured. The primary uncertainty concerns the phase and morphology of NAT particles as they are brought to temperatures >50K above equilibrium temperatures for NAT at stratospheric partial pressures. The slow evaporation of NAT in heated inlets could be used to identify a small NAT component within a mixed phase PSC dominated by STS.

Dual Iminium- and Lewis Base Catalyzed Morita–Baylis–Hillman Reaction on Cyclopent-2-enone

Synlett ◽  
2017 ◽  
Vol 29 (06) ◽  
pp. 820-824 ◽  
Author(s):  
Andrea Trabocchi ◽  
Riccardo Innocenti ◽  
Gloria Menchi
Keyword(s):  
Experimental Evidence ◽  
Lewis Base ◽  
Secondary Amines ◽  
Nucleophilic Attack ◽  
Allylic Alcohols ◽  
Base Catalyst ◽  
Co Catalysts

The application of iminium catalysis to the challenging Morita–Baylis–Hillman reaction on cyclopenten-2-one leads to the corresponding allylic alcohols in excellent yields. Experimental evidence shows that secondary amines act as co-catalysts activating the enone moiety towards the nucleophilic attack at the β-position by DABCO as the Lewis base catalyst, resulting in an augmented nucleophilic character towards the reaction with aldehydes.

scholarly journals A quantitative test of infrared optical constants for supercooled sulphuric and nitric acid droplet aerosols

2003 ◽  
Vol 3 (4) ◽  
pp. 1147-1164 ◽  
Author(s):  
R. Wagner ◽  
A. Mangold ◽  
O. Möhler ◽  
H. Saathoff ◽  
M. Schnaiter ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Data Sets ◽  
Total Water ◽  
Aerosol Composition ◽  
Aerosol Chamber ◽  
Aerosol Parameters ◽  
Aerosol Compositions ◽  
Refractive Index Data ◽  
Filter Analysis

Abstract. In situ Fourier transform infrared (FTIR) extinction spectra of supercooled H2SO4/H2O and HNO3/H2O solution droplets were recorded in the large coolable aerosol chamber AIDA (Aerosol Interactions and Dynamics in the Atmosphere) of Forschungszentrum Karlsruhe for a range of aerosol compositions and at temperatures extending down to 192 K. The measured spectra were quantitatively analysed in terms of aerosol composition and mass concentration by using Mie theory in combination with published refractive index data as input parameters. Simultaneously, total sulphuric acid and nitric acid mass concentrations from filter analysis and total water concentrations measured with the Lyman-a hygrometer of Forschungszentrum Jülich were used to calculate the aerosol composition at thermodynamic equilibrium inside the aerosol chamber. By comparing these measured aerosol parameters with those retrieved from the analysis of the FTIR spectra, the accuracy of the literature data sets of refractive indices could be assessed. In summary, four data sets were tested in the H2SO4/H2O system as well as two data sets in the HNO3/H2O system, partly revealing significant discrepancies in the retrieved aerosol properties. Potential explanations for these differences are discussed in this paper.

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