Essay about Infrared Spectroscopy

757 Words Jan 22nd, 2011 4 Pages
Infrared Spectroscopy

Organic Chemistry Lab 301A

B. The purpose of this lab is to study Infrared Spectroscopy, which focuses on the study of the electromagnetic spectrum. The area to be studied is the infrared region, which is made up of gamma, X, and UV rays. We want to be able to identify spectra’s to their complementary structures. The background of this experiment particularly deals with the study of compound structure determination, and traits. We must be aware of the functional groups that occur in the compounds in order to correctly assess accurate results. Molecular vibrations affect the frequency of the stretch or bend, and the frequency of the bond is determined by 3 types of bonds between atoms. Infrared absorptions are
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We then distinguished the major peaks in the graph and measured its wavelength, which is measured in inverse centimeters, by the numbers located on the bottom of the graph. It was very critical to be exact with our measurements of wavelength because miscalculating it could result in an incorrect determination of the compound type. Once we determined the wavelength of the compound, we looked on the graph that describes the characteristics of infrared absorption frequencies to find the frequency range and bond type that the specific peaks could be categorized into, such as nitriles, amines, alkanes, etc. We finally identified all the bonds shown on the graph and matched it with the structures.
D. Our choices for unknown 5 and 6 were:
Benzaldehyde Benzoic Acid n-Propyl Alcohol

Diethylamine Diethyl Ether Cyclohexane
The first peak of unknown 5 was a C-H bond right at 3000/cm. The second peak was an alkene at a 3080-3020/cm range. The third peak was at the 1000-1470/cm range. Because no double bonds were involved, the unknown couldn’t have been benzaldehyde or benzoic acid. It couldn’t be n-propyl alcohol because it didn’t fall into the alcohol range of frequency at all. It definitely wasn’t diethylamine because it wasn’t in the 1650-1580/cm or 3300-3500/cm range either. This left us with cyclohexane and the only possibility for Unknown #5.
Unknown #6 had a range of 2850-2960/cm Alkanes with a C-H bond, and the third cluster…

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