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>

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>

Polymerization and oxidation of phenols in supercritical water

2019 ◽  
Vol 80 (4) ◽  
pp. 620-633 ◽  
Author(s):  
Huiwen Zhang ◽  
Xiaoman Zhang ◽  
Lei Ding ◽  
Miao Gong ◽  
Ying Su ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Phenolic Compounds ◽  
Supercritical Water ◽  
Water Oxidation ◽  
Reaction Pathway ◽  
Radical Reaction ◽  
Dominant Factor ◽  
Supercritical Water Oxidation ◽  
Free Radical Reaction ◽  
Reaction Conditions

Abstract The treatment of toxic and difficult-to-degrade phenolic compounds has become a key issue in the coking, pharmaceutical, and chemical industries. Considering the polymerization and oxidation of phenolic compounds in supercritical water partial oxidation/supercritical water oxidation (SCWPO/SCWO), the present study reviewed the removal efficiency and reaction pathway of phenolic compounds and phenolic waste/wastewater under different reaction conditions. Temperature is the dominant factor affecting the SCWO reaction. When the oxidizing ability is insufficient, the organics polymerize to form phenolic compounds. The gradual increase of oxidant equivalent causes the intermediate product to gradually oxidize to CO2 and H2O completely. Finally, the free radical reaction mechanism is considered to be a typical SCWO reaction mechanism.

A Study of Electrolysis Technology for the Removal of Nicosulfuron from Dilute Aqueous Solution

2019 ◽  
Vol 298 ◽  
pp. 111-115
Author(s):  
Meng Qi Jiang ◽  
Rui Zhao ◽  
Xin Li Liu
Keyword(s):  
Aqueous Solution ◽  
Radical Reaction ◽  
Chloride Ions ◽  
Free Radical Reaction ◽  
Plant Water ◽  
Sulfonylurea Herbicide ◽  
Reaction Products ◽  
Chlorine Anion ◽  
Dilute Aqueous Solution ◽  
Dilute Aqueous Solutions

Nicosulfuron is a kind of sulfonylurea herbicide used for controlling weeds in corn. In order to solve the problem of plant water with agrochemical, electrolysis was investigated for the treatment of nicosulfuron from dilute aqueous solutions. The operating varieles of time, chlorine anion, pH were experimented and the electrolytic decomposition mechanism of nicosulfuron was suggested. Acid solution was effective for the decomposition of the nicosulfuron and the existence of chloride ions lead to the formation of electrolytic reaction products, which regarded as chloronicosulfuron by HPLC-MS. The reaction is similar to free radical reaction.

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.

Gasification Pathways and Reaction Mechanisms of Primary Alcohols in Supercritical Water

2020 ◽  
Vol 8 (11) ◽  
pp. 4598-4605 ◽  
Author(s):  
Brian R. Pinkard ◽  
John C. Kramlich ◽  
Igor V. Novosselov
Keyword(s):  
Supercritical Water ◽  
Reaction Mechanisms ◽  
Primary Alcohols
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