Experiment 36: Determination of the Structure of a Natural Product in Anise Oil
Name CHE 173 Sec # January 25, 2005 Experiment 36: Determination of the Structure of a Natural Product in Anise Oil
Purpose: The purpose of this experiment is to isolate the major component of anise oil and determine its identity and structure using melting point determination and IR spectroscopy.
Introduction: The major component of anise oil has the chemical formula C10H12O. This compound is said to be hydrogen deficient, meaning that it contains less hydrogen atoms than would be needed for each of the carbon atoms to have the maximum amount of hydrogen atoms attached. The IHD, or index of hydrogen deficiency for this molecule is 10. This indicates that there must be five rings or double bonds in the structure. Each of these would
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This, of course, is assuming that major experimental error did not occur. Since the melting point was slightly higher than the expected value however, it could be determined that some error most likely occurred. For example, the exact starting and ending melting points could have been misjudged. Further error could be found in the final mass of the product. Even though a small yield was expected, it could be seen that some sample was lost in transferring the mixture to different containers. The final mass of the product should have no substantial effect on the melting point analysis. Even with the identity of the product found to most likely be p- methoxybenzoic, the IR spectrum analysis is still necessary. A complete analysis of the IR spectrum can be seen in Table 2, with each peak and its possible corresponding structures. However, as the formula of the structure is already known, only the placement of the second component is needed. Therefore, only the part of the spectrum which considers the placement of the substituents may be analyzed. Ortho substitution has a frequency range of 735-770 (cm-1). Meta substitution has a frequency range of 750-810 and 680-730(cm-1). Para substitution has a frequency range
of 790-840(cm-1). The peaks found on the IR spectrum in these ranges were 787.03 and