Pyrolysis and Oxidative Pyrolysis of Polypropylene

1978 ◽  
pp. 175-197 ◽  
Author(s):  
JAMES C. W. CHIEN ◽  
JOSEPH K. Y. KIANG
Keyword(s):  
Oxidative Pyrolysis

Thermo-Oxidative Decomposition of Lovage (Levisticum officinale) and Davana (Artemisia pallens) Essential Oils under Simulated Tobacco Heating Product Conditions

2020 ◽  
Vol 29 (1) ◽  
pp. 27-43
Author(s):  
Emma Jakab ◽  
Zoltán Sebestyén ◽  
Bence Babinszki ◽  
Eszter Barta-Rajnai ◽  
Zsuzsanna Czégény ◽  
...  
Keyword(s):  
Low Temperature ◽  
Essential Oils ◽  
Relative Yield ◽  
Gas Chromatography Mass Spectrometry ◽  
Intramolecular Rearrangement ◽  
Oxidation Reactions ◽  
Pyrolysis Gas ◽  
Oxidative Decomposition ◽  
Oxidative Pyrolysis ◽  
Artemisia Pallens

SummaryThe thermo-oxidative decomposition of lovage (Levisticum officinale) and davana (Artemisia pallens) essential oils has been studied by pyrolysis-gas chromatography/mass spectrometry in 9% oxygen and 91% nitrogen atmosphere at 300 °C to simulate low-temperature tobacco heating conditions. Both lovage and davana oils contain numerous chemical substances; the main components of both oils are various oxygen-containing compounds. Isobenzofuranones are the most important constituents of lovage oil, and their relative intensity changed significantly during oxidative pyrolysis. (Z)-ligustilide underwent two kinds of decomposition reactions: an aromatization reaction resulting in the formation of butylidenephthalide and the scission of the lactone ring with the elimination of carbon dioxide or carbon monoxide. Davanone is the main component of davana oil, which did not decompose considerably during low-temperature oxidative pyrolysis. However, the relative yield of the second most intensive component, bicyclogermacrene, reduced markedly due to bond rearrangement reactions. Davana ether underwent oxidation reactions leading to the formation of various furanic compounds. The changes in the composition of both essential oils could be interpreted in terms of bond splitting, intramolecular rearrangement mechanisms and oxidation reactions of several constituents during low-temperature oxidative pyrolysis. The applied thermo-oxidative method was found to be suitable to study the stability of the essential oils and monitor the decomposition products under simulated tobacco heating conditions. In spite of the complicated composition of the essential oils, no evidence for interaction between the oil components was found. [Beitr. Tabakforsch. Int. 29 (2020) 27–43]

Laser oxidative pyrolysis synthesis and annealing of TiO2 nanoparticles embedded in carbon–silica shells/matrix

2015 ◽  
Vol 336 ◽  
pp. 226-233 ◽  
Author(s):  
C.T. Fleaca ◽  
M. Scarisoreanu ◽  
I. Morjan ◽  
C. Luculescu ◽  
A.-M. Niculescu ◽  
...  
Keyword(s):  
Tio2 Nanoparticles ◽  
Oxidative Pyrolysis ◽  
Pyrolysis Synthesis

In-depth temperature and smoke production of charring wood under a constant external heat flux

2021 ◽  
pp. 073490412110578
Author(s):  
Yumi Matsuyama ◽  
Fumiaki Takahashi
Keyword(s):  
Ponderosa Pine ◽  
Strong Correlations ◽  
Fire Dynamics ◽  
Oxidative Pyrolysis ◽  
Temperature Trends ◽  
Gasification Rate ◽  
Time Variations ◽  
Smoke Chamber ◽  
Infrared Gas Analyzer ◽  
External Heat Flux

The combustion characteristics of charring wood have been studied experimentally in a well-ventilated environment of a smoke chamber. A numerical simulation has also been performed for a limited case, with the Fire Dynamics Simulator, to estimate the burning environment. A horizontally placed specimen (ponderosa pine) with a moisture content of 0% or 20% is exposed to a radiant flux (25 kW/m2), with or without flaming ignition. Simultaneous measurements of the specimen’s in-depth temperature and the mass loss determine the charring front (rate) at 300 °C and the gasification rate, respectively. These condensed-phase conditions relate directly to real-time variations of gas-phase quantities: the specific optical density of smoke and the concentrations of toxic gases measured by a Fourier transform infrared gas analyzer. In-depth temperature trends are similar whether the flame exists, whereas the smoke and toxicants’ concentrations are substantially different. After the charring front moves through the specimen, the oxidative pyrolysis continues under the irradiation at high temperatures (up to ∼550 °C). Carbon monoxide and acrolein are produced continuously throughout the test, and the results indicate strong correlations. Although char formation of wood is favorable for fire safety, consequent incomplete combustion produces smoke and toxicants.

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