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 Gasification Pathways and Reaction Mechanisms of Primary Alcohols in Supercritical Water

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

<div> <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, e.g., green hydrogen. 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 experiments confirm the dominance of chain-branching, free radical reaction mechanisms that are responsible for decomposing primary alcohols in the supercritical water environment. Reaction pathways and mechanisms for three alcohols are proposed, conversion metrics are presented, and results are compared with known reaction mechanisms for methanol and ethanol oxidation.</p> </div> <br>

Nitrogen Radicals from Thermal and Photochemical Decomposition of Ammonium Perchlorate, Ammonium Dinitramide, and Cyclic Nitramines

1992 ◽  
Vol 296 ◽  
Author(s):  
M. D. Pace
Keyword(s):  
Free Radical ◽  
Ammonium Perchlorate ◽  
Radical Reaction ◽  
Free Radical Reaction ◽  
Ammonium Dinitramide ◽  
Reaction Products ◽  
First Order Kinetics ◽  
Photochemical Decomposition ◽  
Nitrogen Radicals ◽  
Cyclic Nitramines

AbstractFree-radical thermal and photochemical decomposition products of ammonium dinitramide (ADN), an acyclic nitramine, are compared to that of cyclic nitramines (RDX, HMX, and HNIW) and to ammonium perchlorate (AP). Photochemical formation of NO2 from uvphotolysis of ADN at 77 K is found to follow first-order kinetics; whereas, zero-order NO2 formation is observed from the cyclic nitramines under the conditions of this experiment. Mechanisms are suggested for ADN decomposition. A general trend of cyclic nitramines to thermally decompose forming nitroxide radicals is supported by 15N-ring-labeled HNIW results. ADN thermally decomposes at 19° C to form free-radical reaction products in solution with tetrahydrothiophene-1,1-dioxide.

Free-radical reaction of cyanogen bromide with alkanes

1970 ◽  
Vol 48 (10) ◽  
pp. 1492-1497 ◽  
Author(s):  
Dennis D. Tanner ◽  
G. Lycan ◽  
N. J. Bunce
Keyword(s):  
Free Radical ◽  
Benzoyl Peroxide ◽  
Hydrogen Cyanide ◽  
Reaction Mechanisms ◽  
Cyanogen Bromide ◽  
Hydrogen Bromide ◽  
Radical Reaction ◽  
Free Radical Reaction ◽  
Alkyl Bromides ◽  
High Yields

The photolysis of cyanogen bromide with cyclohexane yielded cyclohexyl bromide, hydrogen cyanide, and small amounts of cyanogen, while the benzoyl-peroxide-promoted reactions of cyanogen bromide with various alkanes yielded approximately equal amounts of alkyl bromides and alkyl cyanides, often in high yields. Both hydrogen cyanide and hydrogen bromide were shown to react with benzoyl peroxide and an added hydrocarbon to yield the corresponding alkyl cyanide and alkyl bromide. Possible reaction mechanisms for these reactions are discussed.

scholarly journals Free-Radical Oxidation (Peroxidation) Products in Plasma in Normal and Abnormal Pregnancy

1981 ◽  
Vol 18 (3) ◽  
pp. 158-162 ◽  
Author(s):  
D Wickens ◽  
M H Wilkins ◽  
J Lunec ◽  
G Ball ◽  
T L Dormandy
Keyword(s):  
Blood Pressure ◽  
Free Radical ◽  
Radical Reaction ◽  
Free Radical Oxidation ◽  
Oxidation Products ◽  
Control Group ◽  
Free Radical Reaction ◽  
Reaction Products ◽  
Third Trimester ◽  
Radical Oxidation

Using recently developed methods for measuring free-radical oxidation products in biological material, plasma extracts were studied in 24 women in the first two trimesters of pregnancy, in 124 women in the third trimester of pregnancy, in 20 women with pre-eclamptic toxaemia (PET), and in a control group. There was a significant progressive rise of two groups of free-radical oxidation products throughout pregnancy and a significantly greater rise in PET. In women whose diastolic blood pressure rose to above 70 mmHg there was a highly significant relation between two groups of free-radical reaction products and blood pressure.

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