Production of dl-limonene by vacuum pyrolysis of used tires

Citation
H. Pakdel et al., Production of dl-limonene by vacuum pyrolysis of used tires, J AN AP PYR, 57(1), 2001, pp. 91-107
Citations number
51
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Spectroscopy /Instrumentation/Analytical Sciences
Journal title
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
ISSN journal
0165-2370 → ACNP
Volume
57
Issue
1
Year of publication
2001
Pages
91 - 107
Database
ISI
SICI code
0165-2370(200101)57:1<91:PODBVP>2.0.ZU;2-3
Abstract
Various samples of used car and truck tires were pyrolyzed in a batch mode under vacuum and in a continuous feed reactor. The pyrolysis temperature va ried in the range of 440-570 degreesC. dl-limonene is a major product forme d during the thermal decomposition of rubber under reduced pressure conditi ons. The pyrolysis oils were distilled to obtain a dl-limonene-rich fractio n. The difficulty of obtaining a pure dl-limonene fraction is discussed. A high pyrolysis temperature decreases the dl-limonene yield due to the crack ing of the pyrolysis oil. Several secondary organic compounds produced by c racking were identified by gas chromatography/mass spectrometry (GC/MS) ana lysis. These compounds had a boiling point similar to dl-limonene. The dl-l imonene yield decreases with an increase of the pyrolysis reactor pressure. The mechanism of the thermal degradation of tires leading to the formation of dl-limonene is discussed. A dl-limonene-rich fraction was obtained foll owing a series of distillation. Sulfur-containing compounds in the dl-limon ene-rich fractions were analyzed by GC using a sulfur specific detector. Se veral thiophene-derivatives were identified. Quantitative analysis of the s ulfur compounds in the dl-limonene rich fractions was made. An olfactometry test was performed on a standard thiophene sample in d- and dl-limonene so lutions to establish an approximate threshold value to detect the thiophene odor. (C) 2001 Elsevier Science B.V. All rights reserved.