Pybox Monolithic Miniflow Reactors for Continuous Asymmetric Cyclopropanation Reaction under Conventional and Supercritical Conditions

2007 ◽  
Vol 72 (12) ◽  
pp. 4344-4350 ◽  
Author(s):  
M. I. Burguete ◽  
A. Cornejo ◽  
E. García-Verdugo ◽  
María J. Gil ◽  
S. V. Luis ◽  
...  
Keyword(s):  
Supercritical Conditions ◽  
Asymmetric Cyclopropanation

General Cyclopropane Assembly via Enantioselective Redox-Active Carbene Transfer to Aliphatic Olefins

2018 ◽  
Author(s):  
Marc Montesinos-Magraner ◽  
Matteo Costantini ◽  
Rodrigo Ramirez-Contreras ◽  
Michael E. Muratore ◽  
Magnus J. Johansson ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Asymmetric Synthesis ◽  
Chemical Space ◽  
Synthetic Approach ◽  
Asymmetric Cyclopropanation ◽  
Redox Active ◽  
Wide Range ◽  
Leaving Group ◽  
Stereoelectronic Properties ◽  
Carbene Transfer

Asymmetric cyclopropane synthesis currently requires bespoke strategies, methods, substrates and reagents, even when targeting similar compounds. This limits the speed and chemical space available for discovery campaigns. Here we introduce a practical and versatile diazocompound, and we demonstrate its performance in the first unified asymmetric synthesis of functionalized cyclopropanes. We found that the redox-active leaving group in this reagent enhances the reactivity and selectivity of geminal carbene transfer. This effect enabled the asymmetric cyclopropanation of a wide range of olefins including unactivated aliphatic alkenes, enabling the 3-step total synthesis of (–)-dictyopterene A. This unified synthetic approach delivers high enantioselectivities that are independent of the stereoelectronic properties of the functional groups transferred. Our results demonstrate that orthogonally-differentiated diazocompounds are viable and advantageous equivalents of single-carbon chirons<i>.</i>

COMPARATIVE ANALYSIS OF THE NICOTINE EXTRACTION PROCESS FROM NICOTIANA TABACUM L. IN SUPERCRITICAL CONDITIONS UNDER VARIOUS EXTRACTANT FLOWS

2020 ◽  
Vol 3 (441) ◽  
pp. 59-65
Author(s):  
Y.S. Ikhsanov ◽  
◽  
N.T. Andasova ◽  
A.S. Shevchenko ◽  
M.K. Nauryzbaev ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Nicotiana Tabacum ◽  
Extraction Process ◽  
Supercritical Conditions ◽  
Nicotiana Tabacum L

Energy-saving technologies of technical service and processing of organic waste

2020 ◽  
pp. 65-75
Author(s):  
Anatoliy V. Fedotov
Keyword(s):  
Wastewater Treatment ◽  
Diesel Engine ◽  
Energy Saving ◽  
Organic Waste ◽  
Research Purpose ◽  
Industrial Complex ◽  
Technical Service ◽  
Supercritical Conditions ◽  
Drilling Rig ◽  
Aluminum Oxyhydroxide

Agricultural production in the Russian Federation is several times more energy-and material-intensive than in developed countries. (Research purpose) The research purpose is evaluation of the effectiveness of energy-saving technologies for technical maintenance of equipment using nanostructured aluminum oxyhydroxide and hydrothermal processing of agricultural waste in supercritical conditions. (Materials and methods) Nanostructured aluminum oxyhydroxide (boehmite) was produced by hydrothermal synthesis from aluminum powders. Tribological studies were carried out on a four-ball friction machine, a special device from WAGNER, on friction machines 2070 SMT-1M and MTU. Bench-in run was carried out on the D-240 engine and gearbox of a mobile drilling rig. The crushed solid waste of the agro-industrial complex was used as adsorbents for organic wastewater pollution. Their joint processing was carried out under hydrothermal supercritical conditions. (Results and discussion) It has been shown that nanostructure boehmite has antifriction, antiwear and extreme pressure properties. The possibility of its use as a product for running of a diesel engine has been found. The application of the boehmite in oils accelerates the running-in of a diesel engine, provides savings in material, labor and energy resources. For running-in of power transmission units, an additive containing bemite, surfactant, talc and kaolin reduced the running-in time of the drilling rig gearbox by 2.5 times. The article shows that the crushed plant waste of the agro-industrial complex, such as buckwheat husk, rice, and sunflower can be effectively used as adsorbents for the localization of pollution and wastewater treatment of agricultural enterprises. Subsequent processing of the adsorbent saturated with organic matter under hydrothermal supercritical conditions ensures the complete processing of organic substances to produce purified water and a high-enthalpy vapor-gas mixture or combustible gases, depending on the processing conditions. (Conclusions) Energy-saving technologies for the technical service of a diesel engine and transmission units can be based on the use of tribotechnical materials containing nanostructure boehmite. Technological solutions for energy-saving technologies for processing solid and liquid organic waste can consist in adsorption wastewater treatment followed by hydrothermal treatment in supercritical conditions.

Design and Characterization of Novel Dirhodium Coordination Polymers - The Impact of Ligand Size on Selectivity in Asymmetric Cyclopropanation

2021 ◽  
Author(s):  
Zhenzhong Li ◽  
Lorenz Roesler ◽  
Till Wissel ◽  
Hergen Breitzke ◽  
Kathrin Hofmann ◽  
...  
Keyword(s):  
Coordination Polymers ◽  
Ligand Exchange ◽  
Dicarboxylic Acids ◽  
Sem Images ◽  
Asymmetric Cyclopropanation ◽  
The Impact

Three chiral dirhodium coordination polymers Rh2-Ln (n=1-3) have been synthesized via ligand exchange between dirhodium trifluoroacetate Rh2(TFA)4 and differently sized chiral dicarboxylic acids derived from L-tert-leucine. SEM images indicate that...

Continuous hydrothermal synthesis in supercritical conditions as a novel process for the elaboration of Y-doped BaZrO3

2021 ◽  
Author(s):  
Mélanie François ◽  
Frédéric Demoisson ◽  
Mohamed Sennour ◽  
Gilles Caboche
Keyword(s):  
Hydrothermal Synthesis ◽  
Supercritical Conditions

Hydrothermal Reactions under Supercritical Conditions. II. The Reaction between Calcium Hydroxide and Silica

1957 ◽  
Vol 61 (7) ◽  
pp. 941-943 ◽  
Author(s):  
J F. Corwin ◽  
R. G. Yalman ◽  
J. W. Edwards ◽  
E. R. Shaw
Keyword(s):  
Calcium Hydroxide ◽  
Supercritical Conditions ◽  
Hydrothermal Reactions

Comparative analysis of the physicochemical characteristics of SiO2 aerogels prepared by drying under subcritical and supercritical conditions

2017 ◽  
Vol 53 (12) ◽  
pp. 1270-1278 ◽  
Author(s):  
S. A. Lermontov ◽  
A. N. Malkova ◽  
N. A. Sipyagina ◽  
Kh. E. Yorov ◽  
G. P. Kopitsa ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Physicochemical Characteristics ◽  
Supercritical Conditions
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