Aromatic aryl compounds

Finally, we can show the principal reactions of aromatic compounds. The most simple aromatic (aryl) compound is benzene CeHe, which is similar to the simplest alkane, methane CH4, namely it is very stable against OH attack. Substituted aryl compounds react faster with OH, for example methylbenzenes such as toluene, p-xylene and 1,3,5-trimethylbenzene. The degradation chemistry of aromatic VOC remains an area of particular uncertainty. What is clear is the attack onto the methyl group because it turns into the aldehyde (toluene benzaldehyde). However, about 90 % of the OH attack goes to the ring, generating an adduct called the hydroxycyclohexadienyl radical (Becker et al. 1999). 

As noted above, hydrocarbon compounds contain only carbon and hydrogen. The major types of hydrocarbons are alkanes, alkenes, alkynes, and aromatic (aryl) compounds. Examples of each are shown in Figure 9.3. 

Aromatic (Aryl) Compound 1,2-dimethyl-Benzene (xylene) CsHjo 95-47-6 150 — —... 

Aromatic (Aryl) Compound 2,4,5-trichloro-Phenol C4H3CI3O 95-95-4 150 198 —... 

Aromatic (Aryl) Compound 4-methyl-Phenol CjHjO 106-44-5 151 199 —... 

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