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Isoamyl Acetate Synthesis Lab Report

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Discussion Isoamyl acetate was synthesized by refluxing 1 eq of isopentanol with 4 eq of acetic acid, and 0.5 eq of concentrated sulfuric acid as a catalyst and a dehydrating agent to ensure reaction equilibrium lies far towards the products. The reaction mixture was then added to water and liquid-liquid extraction was conducted. A second extraction was then conducted after adding NaHCO3 solution to the organic layer. This removes the residual acids which are soluble in the aqueous layer. Drying of the crude ester with anhydrous MgSO4 removes H2O that disrupts the NMR and infrared spectrum, hindering the characterization of the product formed. 2.08g of isoamyl acetate was obtained with a percentage yield of 40.4%. This low yield is due to firstly, the theoretical yield of the synthesis is around 80%1 as Fischer esterification being a reversible reaction, does not go to completion. Secondly, isoamyl acetate has a solubility in water of 2mg/ml 2, and thus some product is lost in the …show more content…

However, two anomalies were found in the NMR spectrum. Firstly, for Hc, we expect to see nine peaks for a triplet of a septet with similar 3J coupling constant, but we only see seven. However, the intensity of the 2 terminal peaks in a nonet were probably too small to be noticed. Secondly, the 2nd and 3rd peak from the right for Hc has a larger intensity than the centre peak. From the chemical shift of 1.65ppm, it is most probably water which has a chemical shift of 1.58ppm in CDCl3 3 that overlaps with the 2 peaks, increasing their intensity. As CDCl3 is volatile, the solvent at the dispenser tip evaporates, causing water to condense on the cold tip. Therefore, water may also be dispensed into the NMR tube. The product does not contain significant traces of water as peaks corresponding to the stretching (3750cm-1) and bending (1600cm-1) of H2O were not found in the infrared

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