Caproic Acid Synthesis Essay

1636 Words Dec 9th, 2010 7 Pages
Introduction In this lab, caproic acid was synthesized in a multi-step process that involved the synthesis of three intermediates – diethyl n-butylmalonate, potassium n-butylmalonate, and n-butyl malonic acid respectively. An IR was used to characterize the starting material, n-bromobutane, and the first intermediate, diethyl n-butylmalonate; while IR and NMR were used to characterize the final product, caproic acid.
Reactions, Mechanism and Theory
Caproic acid a.k.a n-hexanoic acid is a carboxylic acid derived from hexane which has the general formula C5H11COOH. It is a colorless oily liquid with a really pungent odor associated with goats. Caproic acid was synthesized in a multi-step process which produced three intermediates -
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The organic layers were then combined and dried with MgSO4. The mixture was filtered and then evaporated to ~100mL. The final solution was then transferred to a 250mL round bottom flask and simple distillation was carried out. After ether and ethanol had distilled off, the diethyl n-butylmalonate was collected. When the distillation temperature reached ~90, the process was stopped and the synthesized diethyl n-butylmalonate was stored in the round bottom flask. An IR of the starting materials, diethyl malonate and n-BuBr, and the product diethyl n-butylmalonate were run. * Synthesis of potassium n-butylmalonate
The diethyl n-butylmalonate was transferred to a small separatory funnel and a condenser, stir bar, Claisen adapter and the separatory flask was attached to the 250mL distillation flask. A solution of 30g KOH in 30mL of water was prepared and this solution was added to the distillation flask. ~5ml of the diethyl n-butylmalonate ester was added to the solution via the dropping funnel and the mixture stirred for 5mins, the remaining ester was then added at a rapid dropwise rate. When addition was complete, the mixture was refluxed on a heating mantle for 45 minutes, and then poured into 90mL of cold water. The mixture was then cooled on ice and NaCl was added until the mixture became saturated. * Synthesis of n-Butyl malonic acid
6M HCl was added to the resulting mixture of potassium n-butylmalonate and the mixture was tested

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