Experiment #5: Esterification of Methyl Benzoate from Benzoic Acid
October 28, 2010
This experiment was conducted to synthesize methyl benzoate from benzoic acid and methanol by using the Fischer esterification method. Methanol (12.5ml) and Benzoic acid (4.9 grams) are heated together in the presence of concentrated sulfuric acid (1.5ml) until equilibrium is achieved. A reflux apparatus is set up for 1 hour to carry out the reaction at the boiling point of the solvent (Methanol, 2.5ml). Then, separation though an extraction apparatus and/ or separatory funnel got rid of the compounds, excluding dichloromethane, in a series of four steps. The basicity had to be tested to check and see whether the unreacted Benzoic acid was removed. Finally, the excess water had to be removed as well to achieve a pure dichloromethane organic layer that would be used for simple distillation. The distillation apparatus separated the dichloromethane from the methyl benzoate by difference in temperature. The Methyl Benzoate could only be achieved when the temperature climbed to 198-199 Celsius. The product will be obtained if the steps are taken very carefully and accurately.
3.72 ml (4.9 g, .041 mol) of Benzoic Acid
12.5ml (9.89g, .309 mol) of Methanol
1.5 ml of Sulfuric Acid
1.5ml (1.63g, .012 mol) of Methyl Benzoate
20 ml of Dichloromethane
15ml of sodium Bicarbonate
15ml of Sodium Chloride
3-4 grams Sodium Sulfate (drying agent)
The benzoic acid, alcohol, and sulfuric acid mixture refluxed for 1 hour then cooled to be added to a separatory funnel later.
-Separatory Apparatus (funnel)-Extraction
Extraction occurred four times in order to remove the alcohol, unreacted benzoic acid, and water from the organic layer, which contained mostly dichloromethane. The simple distillation process separated the dichloromethane from the methyl benzoate at 40 Celsius. The water was...
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