Preparation and Standardization of 0.1 M Sodium Methoxide

Sodium Methoxide Solution Preparation

• Cool 150 ml of anhydrous methanol in ice water and add, in small portions, about 2.5 g of freshly cut sodium. 
• When the metal has dissolved, add sufficient toluene, previously dried over sodium wire to produce 1000 ml. 
• Standardize the solution in the following manner immediately before use.

Sodium Methoxide Solution Standardization

• Weigh accurately about 0.4 g of benzoic acid, dissolve in 80 ml of dimethylformamide.
• Add 0.15 ml of thymolphthalein solution and titrate with sodium methoxide solution to a blue endpoint.
• Protect the solution from atmospheric carbon dioxide throughout the titration. 
• Perform a blank determination and make any necessary correction.
• 1 ml of 0.1 M sodium methoxide is equivalent to 0.01221 g of C7H6O2.
• Store protected from carbon dioxide and moisture.
• Calculate the molarity of solution by the following formula:

                      C7H6O2 in mg
M = ------------------------------------------
      Sodium Methoxide in ml x 12.21
Also see: Determination of Shelf Life of Solutions in Laboratory