Oximinotrifluoromethylation of unactivated alkenes under ambient conditions

2018 ◽  
Vol 54 (64) ◽  
pp. 8885-8888 ◽  
Author(s):  
Na Wang ◽  
Jian Wang ◽  
Yu-Long Guo ◽  
Lei Li ◽  
Yan Sun ◽  
...  
Keyword(s):  
Ambient Conditions ◽  
Reaction Conditions

An oximinotrifluoromethylation of unactivated alkenes was developed via trifluoromethyl radical-induced intramolecular remote oximino migration under mild reaction conditions.

Production and Study of Ca/Sn(II) Metastable Fluoride Ion Conductors

1997 ◽  
Vol 481 ◽  
Author(s):  
Michael F. Bell ◽  
Georges Dénès ◽  
Zhimeng Zhu
Keyword(s):  
Solid Solution ◽  
Electrical Conductivity ◽  
High Temperature ◽  
Calcium Nitrate ◽  
Fluoride Ion ◽  
Conductivity Measurements ◽  
Ambient Conditions ◽  
Reaction Conditions ◽  
Density Measurements ◽  
Ion Conductors

ABSTRACTPrecipitation reactions from aqueous solutions of calcium nitrate and tin(II) fluoride result in the formation of two metastable phases, depending on the reaction conditions. Crystalline CaSn2F6 and the microcrystalline Ca1-xSnxF2 solid solution are obtained, the latter crystallizing in the cubic fluorite (CaF2) type with total Ca/Sn disorder. Both phases are fluoride ion conductors. Electrical conductivity measurements versus temperature and bulk density measurements show that both phases are far from thermodynamic equilibrium at ambient conditions, and thus are metastable. Both decompose to a mixture of SnF2 and CaF2 at high temperature. In addition, CaSn2F6 is chemically unstable in an aqueous medium, in which it looses SnF2 to give the microcrystalline Ca1-xSnxF2 solid solution.

Dry ice-mediated rational synthesis of edge-carboxylated crumpled graphene nanosheets for selective and prompt hydrolysis of cellulose and eucalyptus lignocellulose under ambient reaction conditions

2020 ◽  
Vol 22 (16) ◽  
pp. 5437-5446 ◽  
Author(s):  
Hassan Idris Abdu ◽  
Kamel Eid ◽  
Aboubakr M. Abdullah ◽  
Mostafa H. Sliem ◽  
Ahmed Elzatahry ◽  
...  
Keyword(s):  
Graphene Nanosheets ◽  
Ambient Conditions ◽  
Selective Hydrolysis ◽  
Reaction Conditions ◽  
One Pot ◽  
Dry Ice ◽  
Hydrolysis Of Cellulose ◽  
Hydrolysis Of ◽  
Crumpled Graphene

Edge-carboxylated graphene (ECG) crumpled nanosheets with tuneable COOH content were synthesized by a facile one pot approach for selective hydrolysis of cellulose to glucose and eucalyptus to xylose and glucose under ambient conditions.

scholarly journals Nanofiber-Membrane-Supported TiO2as a Catalyst for Oxidation of Benzene to Phenol

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Chanbasha Basheer
Keyword(s):  
Low Cost ◽  
Laboratory Scale ◽  
Gas Chromatography Mass Spectrometry ◽  
Nanofiber Membrane ◽  
Ambient Conditions ◽  
Glass Capillary ◽  
Reaction Conditions ◽  
Capillary Microreactor ◽  
Oxidation Of Benzene

We applied a simple, low-cost design of glass capillary microreactor for the catalytic oxidation of benzene to phenol at ambient conditions. Polyvinylchloride-nanofiber-membrane-supported titania nanoparticle (TiO2-PVC) as catalyst and in situ production of hydroxyl radicals as oxidant. The reaction was monitored by gas chromatography-mass spectrometry (GC-MS). The reaction conditions were optimized and the performance of the microreactor was then compared with the conventional laboratory scale reaction which used hydrogen peroxide as oxidant. The microreactor gave a better yield of 14% for phenol compared to 0.14% in the conventional laboratory scale reaction. Reaction conditions such as reaction time, reaction pH, and applied potential were optimized. With optimized reaction conditions selectivity of >37% and >88% conversion of benzene were obtained.

scholarly journals One-Pot, Metal-Free Synthesis of Dimethyl Carbonate from CO2 at Room Temperature

2020 ◽  
Vol 1 (3) ◽  
pp. 298-314
Author(s):  
Santosh Govind Khokarale ◽  
Thai Q. Bui ◽  
Jyri-Pekka Mikkola
Keyword(s):  
Ionic Liquid ◽  
Room Temperature ◽  
Dimethyl Carbonate ◽  
High Selectivity ◽  
Chemical Species ◽  
Side Reactions ◽  
Ambient Conditions ◽  
Reaction Conditions ◽  
One Pot ◽  
Metal Free

Herein, we report on the metal-free, one-pot synthesis of industrially important dimethyl carbonate (DMC) from molecular CO2 under ambient conditions. In this process, initially the CO2 was chemisorbed through the formation of a switchable ionic liquid (SIL), [DBUH] [CH3CO3], by the interaction of CO2 with an equivalent mixture of organic superbase 1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU) and methanol. The obtained SIL further reacted with methyl iodide (CH3I) to form DMC. The synthesis was carried out in both dimethyl sulfoxide (DMSO) and methanol. Methanol is preferred, as it not only served as a reagent and solvent in CO2 capture and DMC synthesis, but it also assisted in controlling the side reactions between chemical species such as CH3I and [DBUH]+ cation and increased the yield of DMC. Hence, the use of methanol avoided the loss of captured CO2 and favored the formation of DMC with high selectivity. Under the applied reaction conditions, 89% of the captured CO2 was converted to DMC. DBU was obtained, achieving 86% recovery of its salts formed during the synthesis. Most importantly, in this report we describe a simple and renewable solvent-based process for a metal-free approach to DMC synthesis under industrially feasible reaction conditions.

Out with Acetonitrile: Water-assisted Accelerated-Aging Synthesis of CuI-Pyrazine Hybrid Materials

2021 ◽  
Author(s):  
Will Lucas ◽  
Feier Hou
Keyword(s):  
Hybrid Materials ◽  
Elevated Temperatures ◽  
Accelerated Aging ◽  
Synthetic Method ◽  
Ambient Conditions ◽  
Reaction Conditions ◽  
Dry Grinding ◽  
Excess Amount ◽  
First Time ◽  
Two Hybrid

CuI and pyrazine form three hybrid materials, [(CuI)2(pyrazine)] (Yellow), [(CuI)2(pyrazine)2] (Orange), and [(CuI)(pyrazine)] (Red). In this work, Red was prepared using a green synthetic method, water-assisted accelerated-aging synthesis, for the first time. The syntheses were performed under ambient conditions with only water and no organic solvents. Depending on the reaction conditions, the other two hybrid materials can be formed as well: Orange was formed immediately after dry grinding CuI and pyrazine, while Yellow can be formed from Red and excess amount of CuI at mildly elevated temperatures. The impacts of temperature and types and amounts of liquid added to the aging mixture on the accelerated-aging synthesis were studied, and mechanisms of the synthesis and interconversions between the three CuI-pyrazine hybrid materials were proposed.

Investigating reaction conditions for controlling the self-assembly of metal-seamed pyrogallol[4]arene nanocapsules

2019 ◽  
Author(s):  
◽  
Asanka Sajeewani Rathnayake
Keyword(s):  
Metal Ions ◽  
Self Assembly ◽  
Mixed Valence ◽  
Transition Metal Ions ◽  
Ambient Conditions ◽  
Reaction Conditions ◽  
University Of Missouri ◽  
Reduction Reactions ◽  
Oxidation Reduction ◽  
The University

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Upon coordination to metal ions, C-alkylpyrogallol[4]arenes (PgCn, where n is the number of carbon atoms in the pendant alkyl chains), can be assembled into spherical metal-organic nanocapsules (MONCs). MONCs are generally arranged into two different structural types, hexamers and dimers, of which six or two PgCn units assemble into capsular structures by coordination to 24 or 8 metal ions, respectively. Co[II]-, Zn[II]-, and Mn[II]-coordinated MONCs have been synthesized under ambient conditions and structurally characterized. Under certain reaction conditions, some transition metal ions and other reagents seem to act as electron accepting or donating reagents, such that appropriate oxidation or reduction reactions may occur. These types of in-situ redox reactions lead to the formation of mixed-valence Mn[II]/Mn[III]- and Fe[II]/Fe[III]-seamed MONCs. The occurrence of such oxidation/reduction reactions appears to be promoted by certain factors such as resulting pH conditions, size of the coordinating ions/ligands, and oxidizing/reducing abilities of reagents used in each synthesis. In addition, studies have been carried out to incorporate some defects into the MONC outer framework by using mixed-macrocycles as the starting materials. Mixed-macrocycles are synthesized by fusing both resorcinol and pyrogallol into the same macrocycle, and the position of resorcinol units in the MONC usually appears as a hole or defect on the capsule surface. Incorporations of such defects give MONCs potential for, for example, selective filtering of small molecules into the capsule interior and magnetic and electronic applications by varying the electrostatic interaction between adjacent metal ions.

scholarly journals Catalyst-free, highly selective synthesis of ammonia from nitrogen and water by a plasma electrolytic system

2019 ◽  
Vol 5 (1) ◽  
pp. eaat5778 ◽  
Author(s):  
Ryan Hawtof ◽  
Souvik Ghosh ◽  
Evan Guarr ◽  
Cheyan Xu ◽  
R. Mohan Sankaran ◽  
...  
Keyword(s):  
Material Surface ◽  
Ambient Conditions ◽  
Radical Intermediate ◽  
Solvated Electrons ◽  
Reaction Conditions ◽  
Faradaic Efficiency ◽  
Catalyst Free ◽  
Hydrogen Radical ◽  
Plasma Electrolytic ◽  
Plasma Electrode

There is a growing need for scalable ammonia synthesis at ambient conditions that relies on renewable sources of energy and feedstocks to replace the Haber-Bosch process. Electrically driven approaches are an ideal strategy for the reduction of nitrogen to ammonia but, to date, have suffered from low selectivity associated with the catalyst. Here, we present a hybrid electrolytic system characterized by a gaseous plasma electrode that facilitates the study of ammonia formation in the absence of any material surface. We find record-high faradaic efficiency (up to 100%) for ammonia from nitrogen and water at atmospheric pressure and temperature with this system. Ammonia measurements under varying reaction conditions in combination with scavengers reveal that the unprecedented selectivity is achieved by solvated electrons produced at the plasma-water interface, which react favorably with protons to produce the key hydrogen radical intermediate. Our results demonstrate that limitations in selectivity can be circumvented by using catalyst-free solvated electron chemistry. In the absence of adsorption steps, the importance of controlling proton concentration and transport is also revealed.

A Single Turnover (STO) Characterization of Supported Palladium Catalysts

1987 ◽  
Vol 111 ◽  
Author(s):  
Robert L. Augustine ◽  
David R. Baum
Keyword(s):  
Palladium Catalysts ◽  
Active Sites ◽  
Pt Catalyst ◽  
Catalyst Characterization ◽  
Pt Catalysts ◽  
Ambient Conditions ◽  
Reaction Conditions ◽  
Pd Catalysts ◽  
Supported Pt Catalysts

AbstractWhile the STO catalyst characterization procedure has been applied to a variety of supported Pt catalysts, application of this technique to the characterization of supported Pd catalysts showed that there were several significant differences between the Pt and the Pd catalysts. Under STO reaction conditions each surface site on a Pt catalyst reacts only once so there is a 1:1 relationship between the product composition and the densities of the various types of active sites present. With Pd catalysts under these same conditions, alkene isomerization takes place so readily that the amount of isomerized product formed depends on the contact time of the reactant pulse with the catalyst so there is no direct relationship between the amount of isomerization and the number of isomerization sites present. On Pt there are some direct saturation sites present on which H2 is rather weakly held. Such sites are not present on Pd catalysts. The reactive surface of supported Pt catalysts remains constant on long exposure to air. With Pd catalysts exposure to air results in a decrease in saturation site densities which can be reversed by re-reduction of the surface with H2 under ambient conditions but not completely under what can be termed “reaction conditions” where the extent of surface re-reduction decreases with catalyst age.

Synthesis and characterization of functional six-membered ring carbonates for the preparation of orthogonal couplers

e-Polymers ◽  
2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Thorsten Anders ◽  
Helmut Keul ◽  
Martin Möller
Keyword(s):  
Membered Ring ◽  
Surface Coatings ◽  
Dipolar Cycloaddition ◽  
Ambient Conditions ◽  
Reaction Conditions ◽  
Ring Opening Reaction ◽  
Coupling Principle ◽  
Multifunctional Polymers ◽  
Nucleophilic Ring Opening

Abstract On the basis of commercially available trimethylolpropane (TMP) three six-membered ring carbonates were prepared, substituted with reactive side groups: a chloroformate (2a), an imidazolyl carbamate (2b) and a phenyl carbonate (2c). Their synthesis and characterizations are described and compared to known ring carbonates with reactive side groups. Starting from 2a-c orthogonal couplers 3a and 3b were synthesized for conversion under mild reaction conditions. In a model reaction 2-azidoethyl 2-N-acetylamino-2-deoxy- -D-glucopyranose and tertbutyl- N-(3-aminopropyl) carbamate were linked with coupler 3a via a 1,3-dipolar cycloaddition and a nucleophilic ring-opening reaction. This coupling principle can be used for the preparation of multifunctional polymers or surface coatings at ambient conditions.

AgNPs encapsulated by an amine-functionalized polymer nanocatalyst for CO2 fixation as a carboxylic acid and the oxidation of cyclohexane under ambient conditions

2020 ◽  
Vol 44 (14) ◽  
pp. 5448-5456 ◽  
Author(s):  
Noor Salam ◽  
Priyanka Paul ◽  
Swarbhanu Ghosh ◽  
Usha Mandi ◽  
Aslam Khan ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Co2 Fixation ◽  
Ambient Conditions ◽  
Ag Nps ◽  
Reaction Conditions ◽  
Amine Functionalized ◽  
Propiolic Acid ◽  
Novel Catalyst

A novel catalyst comprising Ag NPs grafted to a porous polystyrene material was synthesized for the production of valuable propiolic acid derivatives via CO2 (1 atm) incorporation, and the oxidation of cyclohexane under ambient reaction conditions.

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