Essay about Organic Chemistry Ii Lab Report

1715 Words Dec 4th, 2015 7 Pages
Torres 1

Luis A. Torres
Group #11
USC Chemistry 322b
Formal Lab Report
6th November 2015

Enzymatic Resolution of 1-Phenylethanol and Diastereomer Analysis
Enzymatic transesterification reaction was performed to study the resolution of diastereomers using 1H-NMR analysis. The stereo-selectivity of acylase I, an enzyme, for a 50:50 racemic mixture of 1-phenylethanol was determined. In the first of a two-step reaction, 1-phenylethanol was reacted with vinyl acetate with the help of acylase I to form an ester, unreacted 1-phenylethanol, and vinyl alcohol. The unreacted 1phenylethanol was separated from the ester by column chromatography and confirmed by thin-layer chromatography (TLC). In the second
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In the first reaction of this experiment, 1-phenylethanol was reacted with vinyl acetate, using the acylase I enzyme. The enzyme’s chirality results in a preferred reaction with one alcohol enantiomer over the other. In the second reaction, the unreacted alcohol is reacted with (R)-(-)-acetoxyphenylacetic acid to create a diastereomer. By comparing the 1H-NMR spectra of the final product diastereomers, we can determine which alcohol enantiomer the enzyme preferred to react with.
We relied on column chromatography to separate the unreacted 1-phenylethanol from the phenylethyl acetate ester. Column chromatography is a useful laboratory technique aimed at separating aqueous and organic components of a mixture.

Torres 3

For this experiment, the lab was separated into groups of four. Each member of the group was responsible for using a sample of 1-phenylethanol. The samples used were detailed in the Objective/Abstract section of this report.

Results and Discussion

H-NMR Analysis:

The 1H-NMRs were produced for all 4 samples, and segments of each can be seen below in Figures 1 – 4. The integrations at 1.5 ppm refers to the (R)-1-phenylethanol while the integrations at 1.4 ppm refers to the (S)-1-phenylethanol. I was unable to use my own unreacted alcohol because TLC analysis shows that I was unable to separate my alcohol from the ester during column chromatography. I used an unreacted alcohol