Benzoic Acid Lab Report

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In this experiment, TLC, IR, and melting point ranges were observed and used to estimate the purity of a solid, which was benzocaine. The percent recovery of the benzocaine was 23.5 %, which indicates how much of the benzocaine component was in the mixture. The percent recovery of the benzoic acid was 44%. Based on the percent recovery of each sample, the amount of original sample that was lost in the extraction and work-up was 32.5 %.
Based on the melting point ranges of the isolated compounds, the purity can be estimated. Based on the literature value of the Benzoic acid which was determined from the Sigma-Aldrich chemistry book available in the lab, to be 121-125 ̊C, the isolated benzoic acid compound was found to be pure because the observed melting …show more content…

Based on the Rf values, the isolated samples can also be considered pure. The Rf value for the reference benzoic acid was calculated to be 0.33, and the value of the benzoic acid was 0.52, there is a difference in these two values, but this was due to smearing or streaking, but there are similarities in the spots. The Rf value for the reference benzocaine was calculated to be 0.31, and the Rf of the benzocaine was 0.29, which indicated very similar vales, which indicated that the isolated sample was indeed pure, and very similar to the reference compound.
When comparing figures 4 and 5, the peaks of the IR spectrum of benzocaine can be observed to determine if the solid is pure. The peaks of the IR spectrum obtained through testing does match the reference IR spectrum. Some examples of the matching frequency, wavelength values are the following; (IR through testing, Reference); (1681.82,~1700), (1126.27,~1120), and (1173.08,~1175). Also, compared to the compound formula, and the IR spectrum, the bonds that correlate to the peaks are as follows; C-H stretches at ~3300, N-H stretch at ~3400, C=O stretch at ~2700, and C-O stretch from ~1000 to

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