scholarly journals Reduction of the Pathways of Photochemical Gasphase Reactions Induced by Multiple Photon IR Laser Excitation of Molecules

1984 ◽  
Vol 4 (1-6) ◽  
pp. 139-150 ◽  
Author(s):  
V. N. Bagratashvili ◽  
M. V. Kuzmin ◽  
V. S. Letokhov
Keyword(s):  
Intermediate Product ◽  
Laser Excitation ◽  
Polyatomic Molecules ◽  
Model Reaction ◽  
Reaction Pathways ◽  
High Yield ◽  
Reaction Products ◽  
Thermal Initiation ◽  
Ir Laser ◽  
High Output

Two different cases, (1) thermal initiation and (2) collisionless IR multiple photon (MP) initiation, of initiating the model reaction of the successive decay of polyatomic molecules ABC → AB + C,AB → A + B are considered for the case when the intermediate product AB is desired. In the case when the desired product AB is thermally less stable than the original one ABC the high output of AB under the thermal initiation is impossible. However by means of IR MP initiation one can obtain a high yield of the desired product, i.e., nearly 100%. The reduction of the chemical reaction pathways takes place for the IR MP initiation. This is due to the extreme intermolecular nonequilibrium achieved under IR MP initiation of the reaction. Unlike the thermal initiation when all the reaction products are of equally high temperature, under IR MP initiation the temperature of the intermediate product TAB is lower than that of the original one TABC and a further decay of the AB species does not occur.

Gold Catalyzed Hydroamination of Propargylic Alcohols: Controlling Divergent Reaction Pathways to Access 1,3-Aminoalcohols, 3-Hydroxyketones or 3-Aminoketones

2018 ◽  
Author(s):  
Victor Laserna ◽  
Tom Sheppard
Keyword(s):  
Gold Catalysis ◽  
Reaction Pathways ◽  
High Yield ◽  
Reaction Conditions ◽  
Propargylic Alcohols ◽  
Catalytic Quantity ◽  
Selective Formation ◽  
General Method

A versatile approach to the valorization of propargylic alcohols is reported, enabling controlled access to three different products from the same starting materials. Firstly, a general method for the hydroamination of propargylic alcohols with anilines is described using gold catalysis to give 3-hydroxy imines with complete regioselectivity. These 3-hydroxyimines can be reduced to give 1,3-aminoalcohols with high syn seletivity. Alternatively, by using a catalytic quantity of aniline, 3-hydroxyketones can be obtained in high yield directly from propargylic alcohols. Further manipulation of the reaction conditions enables the selective formation of 3-aminoketones via a rearrangement/hydroamination pathway.<br>

scholarly journals Gasification Pathways and Reaction Mechanisms of Primary Alcohols in Supercritical Water

2019 ◽  
Author(s):  
Brian Pinkard ◽  
John Kramlich ◽  
Igor V. Novosselov
Keyword(s):  
Free Radical ◽  
Supercritical Water ◽  
Reaction Mechanisms ◽  
Radical Reaction ◽  
Water Environment ◽  
Waste To Energy ◽  
Reaction Pathways ◽  
Free Radical Reaction ◽  
Reaction Products ◽  
Primary Alcohols

<div> <p></p><p>Supercritical water gasification is a promising waste-to-energy technology with the ability to convert aqueous and/or heterogeneous organic feedstocks to high-value gaseous products. Reaction behavior of complex molecules in supercritical water can be inferred through knowledge of the reaction pathways of model compounds in supercritical water. In this study methanol, ethanol, and isopropyl alcohol are gasified in a continuous supercritical water reactor at temperatures between 500 and 560 °C, and for residence times between 3 and 8 s. <i>In situ</i> Raman spectroscopy is used to rapidly identify and quantify reaction products. The results suggest the dominance of chain-branching, free radical reaction mechanisms that are responsible for decomposing primary alcohols in the supercritical water environment. The presence of a catalytic surface is proposed to be highly significant for initiating radical reactions. Global reaction pathways are proposed, and mechanisms for free radical reaction initiation, propagation, and termination are discussed in light of these and previously published experimental results.</p><br><p></p></div>

scholarly journals Gasification Pathways and Reaction Mechanisms of Primary Alcohols in Supercritical Water

2019 ◽  
Author(s):  
Brian Pinkard ◽  
John Kramlich ◽  
Igor V. Novosselov
Keyword(s):  
Free Radical ◽  
Supercritical Water ◽  
Reaction Mechanisms ◽  
Radical Reaction ◽  
Water Environment ◽  
Waste To Energy ◽  
Reaction Pathways ◽  
Free Radical Reaction ◽  
Reaction Products ◽  
Primary Alcohols

<div> <p></p><p>Supercritical water gasification is a promising waste-to-energy technology with the ability to convert aqueous and/or heterogeneous organic feedstocks to high-value gaseous products. Reaction behavior of complex molecules in supercritical water can be inferred through knowledge of the reaction pathways of model compounds in supercritical water. In this study methanol, ethanol, and isopropyl alcohol are gasified in a continuous supercritical water reactor at temperatures between 500 and 560 °C, and for residence times between 3 and 8 s. <i>In situ</i> Raman spectroscopy is used to rapidly identify and quantify reaction products. The results suggest the dominance of chain-branching, free radical reaction mechanisms that are responsible for decomposing primary alcohols in the supercritical water environment. The presence of a catalytic surface is proposed to be highly significant for initiating radical reactions. Global reaction pathways are proposed, and mechanisms for free radical reaction initiation, propagation, and termination are discussed in light of these and previously published experimental results.</p><br><p></p></div>

scholarly journals Chiral Amphiphilic Secondary Amine-Porphyrin Hybrids for Aqueous Organocatalysis

Molecules ◽  
2020 ◽  
Vol 25 (15) ◽  
pp. 3420 ◽  
Author(s):  
Aitor Arlegui ◽  
Pol Torres ◽  
Victor Cuesta ◽  
Joaquim Crusats ◽  
Albert Moyano
Keyword(s):  
Catalytic Activity ◽  
High Yield ◽  
Aldol Reactions ◽  
Free Base ◽  
Reaction Products ◽  
Chirality Transfer ◽  
Base Form ◽  
Low Degree ◽  
Acidic Conditions ◽  
Ph Dependent

Two chiral proline-derived amphiphilic 5-substituted-10,15,20-tris(4-sulfonatophenyl)porphyrins were prepared, and their pH-dependent supramolecular behavior was studied. In neutral aqueous solutions, the free-base form of the hybrids is highly soluble, allowing enamine-based organocatalysis to take place, whereas under acidic conditions, the porphyrinic protonated core of the hybrid leads to the formation of self-assembled structures, so that the hybrids flocculate and their catalytic activity is fully suppressed. The low degree of chirality transfer observed for aqueous Michael and aldol reactions strongly suggests that these reactions take place under true “in water” organocatalytic conditions. The highly insoluble catalyst aggregates can easily be separated from the reaction products by centrifugation of the acidic reaction mixtures, and after neutralization and desalting, the sodium salts of the sulfonated amine-porphyrin hybrids, retaining their full catalytic activity, can be recovered in high yield.

Eosin Thermoluminescence in Polyvinyl Alcohol Films After Doubl Vis-IR Laser Excitation in a Wide Temperature Range

2019 ◽  
Vol 86 (2) ◽  
pp. 232-237 ◽  
Author(s):  
E. I. Konstantinova ◽  
R. Y. Borkunov ◽  
M. V. Tsarkov ◽  
I. G. Samusev ◽  
Y. N. Antipov ◽  
...  
Keyword(s):  
Polyvinyl Alcohol ◽  
Wide Temperature Range ◽  
Laser Excitation ◽  
Temperature Range ◽  
Ir Laser ◽  
Polyvinyl Alcohol Films

Modellreaktionen zur Bildung und Öffnung von Furanen nebeneinander unter Verwendung von Diazocarbonyl-Verbindungen / Model Reaction on Parallel Formation and Ring Opening of Furans by Means of Diazocarbonyl Compounds

1987 ◽  
Vol 42 (11) ◽  
pp. 1487-1491
Author(s):  
Wolfgang Rühl ◽  
Friedrich Bölsing ◽  
Edgar Hofer
Keyword(s):  
Ring Opening ◽  
Decomposition Reaction ◽  
Model Reaction ◽  
Reaction Pathways ◽  
Rearrangement Product ◽  
Wolff Rearrangement ◽  
Photochemical Decomposition

In a photochemical decomposition reaction of the a-Diazoketone 1 in the presence of toluene ring-opening of the adjacent furanoyl substituent occurs as well as conversion of a norcaradiene intermediate thus forming the acetylenic olefinic aldehyde 4 and the dihydrobenzofuran 3. Reaction pathways are derived from the corresponding ketocarbeneoxirene equilibrium in which surprisingly the secondary ketocarbene B-1 gives rise to the formation of the aldehyde 4! No Wolff rearrangement product could be detected.

scholarly journals Optimisation by Design of Experiment of Benzimidazol-2-One Synthesis under Flow Conditions

Molecules ◽  
2019 ◽  
Vol 24 (13) ◽  
pp. 2447 ◽  
Author(s):  
Serena Mostarda ◽  
Tugçe Gür Maz ◽  
Alessandro Piccinno ◽  
Bruno Cerra ◽  
Erden Banoglu
Keyword(s):  
Drug Discovery ◽  
Design Of Experiment ◽  
Model Reaction ◽  
High Yield ◽  
Flow Conditions ◽  
Inflammatory Drug ◽  
Drug Discovery Program ◽  
Scale Preparation ◽  
Privileged Scaffold ◽  
Set Up

A novel flow-based approach for the preparation of benzimidazol-2-one (1) scaffold by the 1,1′-carbonyldiimidazole (CDI)-promoted cyclocarbonylation of o-phenylenediamine (2) is reported. Starting from a preliminary batch screening, the model reaction was successfully translated under flow conditions and optimised by means of design of experiment (DoE). The method allowed the efficient preparation of this privileged scaffold and to set up a general protocol for the multigram-scale preparation in high yield, purity, and productivity, and was successfully applied for the multigram flow synthesis of N-(2-chlorobenzyl)-5-cyano-benzimidazol-2-one, which is a key synthon for hit-to-lead explorations in our anti-inflammatory drug discovery program.

scholarly journals Novel reaction products from simple organic reactions: Delineation of reaction pathways

1996 ◽  
Vol 68 (3) ◽  
pp. 739-742 ◽  
Author(s):  
S. C. Jain ◽  
S. Talwar ◽  
Sunita Bhagat ◽  
V. K. Raiwanshi ◽  
R. Kumar ◽  
...  
Keyword(s):  
Organic Reactions ◽  
Reaction Pathways ◽  
Reaction Products

The Curing Reaction of 3-Aryl Substituted Benzoxazine

2000 ◽  
Vol 12 (1) ◽  
pp. 237-246 ◽  
Author(s):  
Teruaki Hayakawa ◽  
Yoshinori Osanai ◽  
Kouichi Niizeki ◽  
Osamu Haba ◽  
Mitsuru Ueda
Keyword(s):  
Nmr Spectroscopy ◽  
Thermal Treatment ◽  
Early Stage ◽  
Model Reaction ◽  
Reaction Pathways ◽  
Intramolecular Rearrangement ◽  
H Nmr ◽  
Curing Reaction ◽  
Toluenesulfonic Acid

The reaction pathways on the curing reaction of 3-aryl substituted benzoxazine was investigated from the model reaction of 3, 4-dihydro-6, 8-dimethyl-3-phenyl-2H-1, 3-benzoxazine (1) with 2, 4-xylenol (2). The reaction was carried out at 140 °C for 5 h. N, N-Bis(2-hydroxy-3, 5-dimethylbenzyl)phenylamine (3) and N-(2-hydroxy-3, 5-dimethylbenzyl)phenylamine (4) were isolated as main products at an early stage. The reaction of 3 by the thermal treatment was studied by 1H-NMR spectroscopy. This result indicates that compound 3 produces several inter- and intramolecular rearrangement products. Based on these data, some possible reaction pathways were proposed. In the presence of p-toluenesulfonic acid monohydride, 3,3′-[4,4′-methylenediphenyl]bis(3,4-dihydro-6,8-dimethyl-2H-1,3-benzoxazine) (9) was isolated as one of the intermediates.

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