Benzoin Synthesis Lab Report

The benzoin is oxidized with nitric acid to produce benzyl. When benzoin was reacted with nitric acid, an orange color appeared. When was heated the mixture a strong red color appeared in the reflux condenser, which is the visible liberation of nitrogen oxide gases. A total of 0.10 grams of purified benzil was produced from this reaction which contained a detected melting point of 82°C and a 34 % yield. This seemed to be approximately 10 degrees less than the ideal melting point of 94°C, which could be interpreted as deficiency of purity. The infrared spectroscopy, support this reasoning because shows a peak at 3316.65 cm-1, that appears to be a residues of water. This means that during the drying of the crystals on the Hirsch funnel the procedure failed. We can also see on the infrared spectroscopy, peaks at 1656 cm-1 indicating the double bond between carbon and oxygen. Three peaks appeared between 1449.60 cm-1 and 1591.91 cm-1 accounting for the carbons within the aromatic ring, and peaks of carbon hydrogen at 2980.89 cm-1 This data …show more content…
This is the intermediate step to produce potassium benzilate. After workup, the mixture was partially solid, but we assume that the crystallization was not completed. Because when we move to the next step of convert the crystals of potassium benzilate to crystals of Benzilic acid, the crystallization of Benzilic acid never performed. We assume that the mistake was made during the process of the first crystallization. As we mention above, we believe the crystals of potassium benzilate was not completed in its entirely in the ice-water bath. That is why when we wash the crystals in the Hirsch funnel just a few of crystals was obtained, the rest were completely dissolved with 95% of ice ethanol. Those few crystal was not enough to produce Benzilic acid. At the end, we had to use information from other peers to complete our