Combine 66.4 g of potassium iodide, 120 mL of methanol and 175 mL of 85% phosphoric acid in a RBF, set up for a simple distillation, distill slowly for 3 h, receiving flask should be cooled with an ice bath. Pour the distillate into a separatory funnel and discard the aqueous layer. Then wash the distillate with 40 mL of conc. sodium chloride solution with few grams of sodium thiosulfate, shake, discard the upper layer, then wash with 40 mL of water. Dry with some anhydrous calcium chloride, store with few grams of copper wire to stabilize it.
Crude methyl iodide
Washing with sodium chloride thiosulfate solution.
Drying with anhydrous calcium chloride