ABSTRACT
Aldehydes, ketones, esters, anhydrides, acid chlorides and carboxylic acids show some near-infrared (NIR) carbonyl associated bands, as illustrated in Figure 7.1. The C=O stretch is very strong in the mid-IR; so even though the Œrst overtone is still in the mid-IR region, the second overtone may be strong enough to observe in the NIR. Although the second overtones are relatively weak and would be overwhelmed if any water was present, there are some anhydrous situations in which it might be useful to analyze carbonyl compounds by NIR spectroscopy.
