Aromatic flow chart

Pyridine adsorption. From Flow Chart 1 we can see that pyridine can either coordinate on a Lewis acidic site or react with a Bronsted acidic site. In this latter case a pyridinium ion is formed with characteristic absorption frequencies (30). Two fundamental modes of the aromatic ring and Vg are sensitive to the coordination state of the pyridine. Thus they are good sensors of the Lewis acid strength since the frequency shifts are directly related to it. 

FIGURE 14.20 A flow chart of the hydrocarbon classification emphasizing the aromatic classification to be discussed next in the text. 

As the methanol flows through the reactor, from left to right on the chart, it changes very rapidly into new chemicals and changes again before it finally becomes the mixture of paraffins, aromatics and olefins that we call gasoline. 

Chart 11.5 Generic depiction (on the left-hand side) of metal-to-aromatic re-backbonding with benzene used as the aromatic substrate (arrows denote flow of electron density from the metal dre orbital to the aromatic C=C re molecular orbital). On the right-hand side, conversion of T)2-benzene complex to phenyl hydride complex, via C—H oxidative addition, restores aromaticity. 

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