The products of the pyrolysis of four sesquiterpenes, β-caryophyllene, α-cedrene, longifolene and valencene, have been examined. Pyrolysis was carried out at 300, 400 and 500°C, the products determined by GC-MS and then examined for similarities and differences using multivariate data analysis. Analysis showed that longifolene was most resistant and caryophyllene least resistant to pyrolysis with cedrene and valencene occupying intermediate positions. While the compounds were largely unchanged at 300°C, polycyclic aromatic hydrocarbons (PAHs) were major components of the pyrolysates at 400 and 500°C. No less than nine of the 16 EPA priority pollutants were present in the pyrolysates at the higher temperatures.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.foodchem.2012.06.033 | DOI Listing |
Chemphyschem
January 2025
The University of Sheffield, school of mathematical and physical sciences, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND.
Pentalene (C8H6) and NN- and BB-bridged heterocyclic analogues (BN)4H6, derived by replacement of CC pairs with BN, are taken as paradigms for tuning of ring-current (anti)aromaticity by variation of π charge, electronegativity and substitution pattern. Ab initio calculation of maps for the π current density induced in these model systems by a perpendicular external magnetic field exhibits the full range of tropicity, from diatropic aromatic to nonaromatic to paratropic antiaromatic, with a ready rationalisation in terms of an orbital model. Further calculations on systems of varying charge in which these motifs are embedded in extended PAH systems with naphthalene and phenanthrene 'clamps' show promise for switching between current patterns and related opto-electronic properties.
View Article and Find Full Text PDFChem Asian J
January 2025
Xiamen University, Department of Chemistry, Xiamen University, Lujiaxi Building Room 742, 361005, xiamen, CHINA.
The direct construction of polycyclic arenes through ring formation using simple building blocks is highly appealing but remains challenging in organic chemistry. In this study, we introduce an efficient cascade reaction that combines dearomatizing photocyclization with oxidative aromatization, driven by organophotocatalysis. Conducted under mild, transition-metal-free conditions, this reaction seamlessly converts styrene derivatives into a diverse array of functionalized polycyclic aromatic compounds with good yields and regioselectivity.
View Article and Find Full Text PDFChemphyschem
January 2025
Institute of Molecular Science Marseille, Département de chimie, FRANCE.
Electron delocalization is studied in the ground singlet and first excited triplet states of azulene-containing helicenes. After showing that the compounds we study can be synthesized, we show that they exhibit a charge separation in the ground state, which does not appear in their triplet excited state. Then, magnetically induced properties (IMS3D and ACID) and electron density decomposition methods (EDDB) are used to rationalize aromaticity in these systems.
View Article and Find Full Text PDFFood Chem Toxicol
January 2025
School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, 518107, China. Electronic address:
Exposure to polycyclic aromatic hydrocarbons (PAHs) and tobacco smoke is widespread and linked to various adverse health outcomes. Their potential to disturb the neurological system has raised much concern, particularly among older adults. Thus, we conducted a case-control study to assess the associations between co-exposure to PAHs and nicotine, and the risk of cognitive impairment and oxidative stress in older adults.
View Article and Find Full Text PDFDev Cogn Neurosci
January 2025
Department of Psychiatry and Behavioral Health, The Ohio State University, Columbus, OH, United States; The Child Mind Institute, New York, NY, United States. Electronic address:
Reading difficulties and exposure to air pollution are both disproportionately high among youth living in economically disadvantaged contexts. Critically, variance in reading skills in youth living in higher socioeconomic status (SES) contexts largely derives from genetic factors, whereas environmental factors explain more of the variance in reading skills among youth living in lower SES contexts. Although reading research has focused closely on the psychosocial environment, little focus has been paid to the effects of the chemical environment.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!