Chemistry of carbonization—I. A theoretical study of free radical formation from starting materials

✍ Scribed by Fernando Ruette; Anibal Sierraalta; Victoria Castells; Manuel Laya

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 800 KB
• Volume: 31
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/0008-6223(93)90120-y

✦ Synopsis

The effect of size, shape, and aromaticity in the formation of radicals from model polyaromatic hydrocarbons (PAH) was theoretically studied using the MINDOI3 method. The results were interpreted in terms of hydrogen transfer on carbonization and liquefaction processes of coal-related compounds. Additives that donate or withdraw electrons were modeled by calculating negatively or positively charged systems. The results show that the hydrogen donating properties of PAHs increase with the increase of their molecular weights. The formation of anionic n-radicals is thermodynamically favored, contrary to cationic n-radicals. Negative charge favored the formation of low molecular weight radicals, and therefore, the hydrogen transfer from light to heavy PAHs. Positive charges, in general, do not facilitate the hydrogen transfer.