Methyl Benzoate from Benzoic Acid

Esterification: Methyl Benzoate From Benzoic Acid

Introduction

The purpose of this experiment is to convert benzoic acid to Methyl Benzoate using an acid catalyst. In accordance with Le Chatelier’s principle, a large amount of methanol will be used to drive the the equilibrium towards the product. The product will be isolated upon neutralization of the acid catalyst. The purity will then be confirmed by infrared spectroscopy technique.

Main Reaction

Benzoic Acid + Methanol ----------> Methyl Benzoate + Water

Mechanism

Side Reactions

No Side Reactions

Table of Reactants and Product(s)

Compound Molecular Weight (g/mol) Amount Used Moles Used (mol) Melting Point (ºC) Boiling Point (ºC) Hazards

Benzoic Acid 122.21 10 g 0.082 122.4 249.0 Irritant

Methanol 32.04 25 mL 0.62 -97.0 64.7 Flammable

Methyl Benzoate 136.15 -12.5 199.6 None

Sulfuric Acid 98.087 3 mL 10.0 290.0 Corrosive

Dichloromethane 84.93 50 mL -96.7 39.0 Carcinogen

Sodium Bicarbonate 84.007 40 mL 50.0 Irritant

Hydrochloric Acid 36.46 -26.0 110.0 Corrosive

Anhydrous Sodium Sulfate 142.04 884 1429 Irritant

Post Lab: Esterification: Methyl Benzoate From Benzoic Acid

Experimental

The 100 mL round bottom flask was washed with methanol, dried and 9.894 g of benzoic acid and a stirring bar was added to it. Then, 25 mL of methanol was added to the flask followed by 3 mL of sulfuric acid. The reflux condenser was then attached to the round bottom flask water was allowed to run through it. The flask was placed in an empty sand bath. This apparatus was then placed on a hotplate and secured. The sand bath and the hotplate’s stirring mode were turned on to heat and stir the reactant in the flask. The sand bath was adjusted so that the mixture was at reflux.

After an hour, the solution was cooled in an ice bath. While the solution was cooling, the separatory funnel was washed 3 times with deionized water and 50 mL of deionized...