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Reaction Pathways of Molecular Growth for Bay-Region Methyl-Substituted Polycyclic Aromatic Hydrocarbons During Supercritical Pyrolysis of n-Decane.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Reaction Pathways of Molecular Growth for Bay-Region Methyl-Substituted Polycyclic Aromatic Hydrocarbons During Supercritical Pyrolysis of n-Decane./
作者:	Vutukuru, Venkata Sai Krishna Karthik.
面頁冊數:	1 online resource (238 pages)
附註:	Source: Dissertations Abstracts International, Volume: 83-11, Section: B.
Contained By:	Dissertations Abstracts International83-11B.
標題:	Aircraft. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=29111191click for full text (PQDT)
ISBN:	9798426897892

Reaction Pathways of Molecular Growth for Bay-Region Methyl-Substituted Polycyclic Aromatic Hydrocarbons During Supercritical Pyrolysis of n-Decane.
Vutukuru, Venkata Sai Krishna Karthik.

Reaction Pathways of Molecular Growth for Bay-Region Methyl-Substituted Polycyclic Aromatic Hydrocarbons During Supercritical Pyrolysis of n-Decane. - 1 online resource (238 pages)

Source: Dissertations Abstracts International, Volume: 83-11, Section: B.

Thesis (Ph.D.)--Louisiana State University and Agricultural & Mechanical College, 2021.

Includes bibliographical references

Prior to its combustion, fuel for future-highspeed aircraft will experience supercritical conditions, causing the fuel to undergo pyrolytic reactions that lead to the formation of polycyclic aromatic hydrocarbons (PAH), precursors to fuel-line solids that hinder aircraft's safe operation. Therefore, understanding the formation pathways of PAH under supercritical conditions is important to preventing formation of these solids.Previous work from our group has shown that n-alkanes are particularly problematic regarding solids formation and that the model fuel n-decane produces an abundance of aliphatics and one- to nine-ring aromatics-many of which are methyl-substituted. Some of these methylsubstituted PAH have their methyl group in a bay-region, making them highly reactive. Therefore, to investigate the molecular-growth reactions of bay region methyl-substituted PAH in the supercritical n-alkane-pyrolysis environment, we have performed supercritical n-decane pyrolysis experiments in an isothermal, isobaric flow reactor at 568 °C, 94.6 atm, and 133 sec, conditions of rapid PAH growth, with two dopants-4-methylchrysene and 4-methylphenanthrene-added in separate experiments. The aliphatics and one- and two-ring aromatics are analyzed by gas chromatography. The complex PAH products are analyzed, isomer-specifically, by a twodimensional high-pressure liquid-chromatographic technique.The 4-methylchrysene-doping experiments reveal that the molecular growth of 4- methylchrysene proceeds along two distinctive routes, each starting from its arylmethyl radical's reaction with the aryl carbon across the bay to make a C19H12 PAH and its resonance-stabilized radical. One of these radicals, 4-benzo[cd]fluoranthenyl, reacts with n-decane's abundant aliphatic species methyl and the C2-C4 1-alkenes to produce six- and seven-ring PAH with internal 5- membered rings; the other, 4-cyclopenta[def]chrysenyl, initiates a series of reactions with these same aliphatic species to produce peri-condensed benzenoid PAH as large as nine-rings. In the supercritical n-decane-pyrolysis environment, 4-methylphenanthrene exhibits analogous molecular-growth reactions-substantiating the distinctive growth behaviors of bay-region methyl-substituted PAH.Previous investigations from our group have revealed that temperature has a strong influence on the supercritical pyrolysis behavior of n-decane. To investigate the behavior of n-decane at lower temperatures, we have performed additional pyrolysis experiments at 94.6 atm, 133 sec, and four temperatures ranging from 495 to 520 oC. Product analyses have led to the quantification of 62 new products.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2023

Mode of access: World Wide Web

ISBN: 9798426897892Subjects--Topical Terms:

832698
Aircraft.
Index Terms--Genre/Form:

542853
Electronic books.

Reaction Pathways of Molecular Growth for Bay-Region Methyl-Substituted Polycyclic Aromatic Hydrocarbons During Supercritical Pyrolysis of n-Decane.
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100 1 $a Vutukuru, Venkata Sai Krishna Karthik. $3 3694512
245 1 0 $a Reaction Pathways of Molecular Growth for Bay-Region Methyl-Substituted Polycyclic Aromatic Hydrocarbons During Supercritical Pyrolysis of n-Decane.
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500 $a Source: Dissertations Abstracts International, Volume: 83-11, Section: B.
500 $a Advisor: Wornat, Mary Julia.
502 $a Thesis (Ph.D.)--Louisiana State University and Agricultural & Mechanical College, 2021.
504 $a Includes bibliographical references
520 $a Prior to its combustion, fuel for future-highspeed aircraft will experience supercritical conditions, causing the fuel to undergo pyrolytic reactions that lead to the formation of polycyclic aromatic hydrocarbons (PAH), precursors to fuel-line solids that hinder aircraft's safe operation. Therefore, understanding the formation pathways of PAH under supercritical conditions is important to preventing formation of these solids.Previous work from our group has shown that n-alkanes are particularly problematic regarding solids formation and that the model fuel n-decane produces an abundance of aliphatics and one- to nine-ring aromatics-many of which are methyl-substituted. Some of these methylsubstituted PAH have their methyl group in a bay-region, making them highly reactive. Therefore, to investigate the molecular-growth reactions of bay region methyl-substituted PAH in the supercritical n-alkane-pyrolysis environment, we have performed supercritical n-decane pyrolysis experiments in an isothermal, isobaric flow reactor at 568 °C, 94.6 atm, and 133 sec, conditions of rapid PAH growth, with two dopants-4-methylchrysene and 4-methylphenanthrene-added in separate experiments. The aliphatics and one- and two-ring aromatics are analyzed by gas chromatography. The complex PAH products are analyzed, isomer-specifically, by a twodimensional high-pressure liquid-chromatographic technique.The 4-methylchrysene-doping experiments reveal that the molecular growth of 4- methylchrysene proceeds along two distinctive routes, each starting from its arylmethyl radical's reaction with the aryl carbon across the bay to make a C19H12 PAH and its resonance-stabilized radical. One of these radicals, 4-benzo[cd]fluoranthenyl, reacts with n-decane's abundant aliphatic species methyl and the C2-C4 1-alkenes to produce six- and seven-ring PAH with internal 5- membered rings; the other, 4-cyclopenta[def]chrysenyl, initiates a series of reactions with these same aliphatic species to produce peri-condensed benzenoid PAH as large as nine-rings. In the supercritical n-decane-pyrolysis environment, 4-methylphenanthrene exhibits analogous molecular-growth reactions-substantiating the distinctive growth behaviors of bay-region methyl-substituted PAH.Previous investigations from our group have revealed that temperature has a strong influence on the supercritical pyrolysis behavior of n-decane. To investigate the behavior of n-decane at lower temperatures, we have performed additional pyrolysis experiments at 94.6 atm, 133 sec, and four temperatures ranging from 495 to 520 oC. Product analyses have led to the quantification of 62 new products.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2023
538 $a Mode of access: World Wide Web
650 4 $a Aircraft. $3 832698
650 4 $a Hydrogen. $3 580023
650 4 $a Decomposition. $3 3561186
650 4 $a Heat. $3 573595
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650 4 $a Free radicals. $3 3682274
650 4 $a Carbon. $3 604057
650 4 $a Polycyclic aromatic hydrocarbons. $3 697430
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650 4 $a Engineering. $3 586835
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710 2 $a Louisiana State University and Agricultural & Mechanical College. $3 783779
773 0 $t Dissertations Abstracts International $g 83-11B.
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=29111191 $z click for full text (PQDT)