The potassium salt of benzoic acid, potassium benzoate (KC ₇ H ₅ O ₂ ) can be made by the action of potassium permanganate on toluene (C ₇ H ₈ ) as follows:

C ₇ H ₈ + 2KMnO ₄ ? KC ₇ H ₅ O ₂ + 2MnO ₂ + KOH + H ₂ O

If the yield of potassium benzoate cannot realistically be expected to be more than 61.8%, what is the minimum number of grams of toluene needed to achieve this yield while producing 16.7 g of potassium benzoate?