Greetings,
This post will focus on yet another bonding-ability of benzene; that is to fuse with other benzene rings. When benzene rings fuse, hydrogen atoms are lost from the common carbon atoms of the "fused side". In reality, whole benzene rings do not combine, rather a complex mechanism occurs whereby a single benzene ring combines with unsaturated hydrocarbons, such as butadiene. Studies have been done at Oak Ridge National Laboratory to better understand formation of PAH's. One particular study proposed that PAH's are commonly produced via pyrolysis of plant terpenes (such as beta-Carotene) and steroid compounds.(1) Pyrolysis is the thermal degradation process, which occurs when materials are brought to elevated temperatures (450+ deg. C) in the absence of air.(2) PAH's are naturally produced from combustion processes with limited amounts of oxygen, such as cigarette smoking and coal combustion. (3)
PAH's are a serious health concern. As a chief component of industrial smog, PAH's easily enter a person's body by way of the lungs. Many PAH's are known carcinogens.(4) Fortunately for the U.S., The Clean Air Act of 1990 has resulted in great reductions air pollution emissions. (5)
The following slide presentation shows several of the most basic PAH's.
Again, in reality, individual benzene rings do not actually combine.
That's all for now. As always, thank you for reading!
1. https://web.anl.gov/PCS/acsfuel/preprint%20archive/Files/49_2_Philadelphia_10-04_1186.pdf
2. http://www.ars.usda.gov/Main/docs.htm?docid=19898
3. http://www.atsdr.cdc.gov/csem/csem.asp?csem=13&po=5
4. http://www.atsdr.cdc.gov/csem/csem.asp?csem=13&po=11
5. http://www.epa.gov/laws-regulations/summary-clean-air-act
A Publication of http://ExcellenceInLearning.biz
This post will focus on yet another bonding-ability of benzene; that is to fuse with other benzene rings. When benzene rings fuse, hydrogen atoms are lost from the common carbon atoms of the "fused side". In reality, whole benzene rings do not combine, rather a complex mechanism occurs whereby a single benzene ring combines with unsaturated hydrocarbons, such as butadiene. Studies have been done at Oak Ridge National Laboratory to better understand formation of PAH's. One particular study proposed that PAH's are commonly produced via pyrolysis of plant terpenes (such as beta-Carotene) and steroid compounds.(1) Pyrolysis is the thermal degradation process, which occurs when materials are brought to elevated temperatures (450+ deg. C) in the absence of air.(2) PAH's are naturally produced from combustion processes with limited amounts of oxygen, such as cigarette smoking and coal combustion. (3)
PAH's are a serious health concern. As a chief component of industrial smog, PAH's easily enter a person's body by way of the lungs. Many PAH's are known carcinogens.(4) Fortunately for the U.S., The Clean Air Act of 1990 has resulted in great reductions air pollution emissions. (5)
The following slide presentation shows several of the most basic PAH's.
Again, in reality, individual benzene rings do not actually combine.
That's all for now. As always, thank you for reading!
1. https://web.anl.gov/PCS/acsfuel/preprint%20archive/Files/49_2_Philadelphia_10-04_1186.pdf
2. http://www.ars.usda.gov/Main/docs.htm?docid=19898
3. http://www.atsdr.cdc.gov/csem/csem.asp?csem=13&po=5
4. http://www.atsdr.cdc.gov/csem/csem.asp?csem=13&po=11
5. http://www.epa.gov/laws-regulations/summary-clean-air-act
A Publication of http://ExcellenceInLearning.biz
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