Experiment 25 Qualitative Analysis by Infrared Spectrometry

In this experiment you will be given two unknown organic liquids to attempt to identify by infrared spectrometry. For one of the unknowns you will be given its molecular formula. The other must be identified by matching its infrared spectrum to a spectrum in a reference catalog of spectra (sometimes called a spectral library). 

Safety note Avoid contact of all organic compounds with your skin (wear gloves) and also avoid breathing the vapors as much as possible. 

Obtain the two unknowns from your instructor. One will have an identifying number, and the other will have an identifying letter. For the one identified by a number, obtain its molecular formula from your instructor. Record all information. 

Obtain the infrared spectra of the two liquids by whatever method suggested by your instructor (liquid sampling cell or disposable card). 

Attempt to identify the unknown labeled with a letter by matching the spectrum with a spectrum from the IR spectral library. First, take a preliminary look at the spectrum to check for obvious signs of the various functional groups (refer to Table 8.1 or a correlation chart). This will help reduce the number of possibilities. Report your decision regarding its identity to your instructor and justify your decision. 

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