1. Today: IR Next time: (see our website!) Partition coefficient and partition calculations Separations of mixtures

2. IR spectroscopy deals with the interactions between a molecule and radiation from the IR region of the electromagnetic spectrum IR radiation causes the excitation of the natural vibrations of covalent bonds within that molecule and includes stretching and bending modes (C 334 molecular modeling experiments!) Infrared (IR) spectroscopy IR region = 4000 - 400 cm -1 (cm -1 unit is the wave number scale and is given by 1/wavelength in cm) E= h Excitation of the natural vibrations of a bond leads to absorption of light of typical frequencies. This is recorded as a minimum on the IR spectrum. The frequencies are typical for the atoms and bond types involved and allow us to determine functional groups. http://www.chem.ucla.edu/~webspectra/index.html

3. butyl acetate Fingerprint region

4. http://www.chem.ucla.edu/~webspectra/index.html

6. Aromatics

7. http://www.chem.ucla.edu/~webspectra/index.html

9. Alcohols Gas phase! OH non-hydrogen bonded

10. Phenol OH hydrogen bonded

12. Ketones

13. Carboxylic Acids

14. ? ? ? ? C 6 H 12 O 2

15. Next time: Partition coefficient and partition calculations Separations of mixtures (Print out from our Website and bring to class)