Preparation and Standardization of 0.1 M Lithium Methoxide

Lithium Methoxide Solution Preparation

• Dissolve in small portions 0.7 g of freshly cut lithium in 150 ml of anhydrous methanol, cooling the flask during the addition of the metal.
• When the reaction is complete add sufficient toluene to produce 1000 ml.
• If cloudiness or precipitation occurs, add sufficient anhydrous methanol to clarify the solution.
• Standardise the solution immediately before use in the following manner.

Lithium Methoxide Solution Standardization

• Weigh accurately about 0.25 g of benzoic acid, dissolved in 25 ml of dimethylformamide.
• Titrate with lithium methoxide solution, using quinaldine red solution as the indicator and protecting the solution from atmospheric carbon dioxide throughout the titration.
• Perform a blank determination and make any necessary correction.
• 1 ml of 0.1 M lithium methoxide is equivalent to 0.01221 g of C7H6O2.
• Calculate the molarity of solution by the following formula:

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