Preparation of Diazomethane
Typical Procedure:A reaction and distillation apparatus is assembled by connecting an addition funnel and condenser to a 100 mL long-neck distillation flask. Two in series receiving flasks are connected to the apparatus with the second flask containing an induction tube. A solution containing 6 g potassium hydroxide in 10 mL water, and a solution containing 35 mL carbitol (diethylene glycol monoethyl ether) and 10 mL of ether are placed in the distillation flask. 20~30 mL ether is placed in the second receiving flask making sure the induction tube is immersed into the ether. Both receiving flasks are cooled to 0 ℃. A solution containing N-methyl-N-nitroso-p-toluenesulfonamide (21.5 g, 0.1 mol) in 140 mL ether is placed in the addition funnel. Heat the distillation flask to 70 ℃ in a warm water bath. As the ether begins to boil, start adding the N-methyl-N-nitroso-p-toluenesulfonamide solution dropwise over a 20 minute period. Swirl distillation flask from time to time. About 3 g of diazomethane (0.07 mol) is dissolved in ether distillate. The reagent should be used at once without storing it.
*Note: Diazomethane is explosive and highly toxic. Wear protective gloves, protecting goggles, protective mask and work in a well ventilated fume hood. Also place a safety shield in front of distillation apparatus. Diazomethane may explode upon contact with ground glass joints or other scratched glass surfaces, so avoid handling or preparing this compound with such surfaces. Ordinarily, diazomethane is used as a solution in ether.
*We have TMS diazomethane (T1146) available. This reagent is analogous in reactivity to diazomethane, but less explosive and less toxic. Please consider using this reagent prior to preparing diazomethane.
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Org. Synth. 1963, Coll. Vol. 4, 250.; Org. Synth. 1973, Coll. Vol. 5, 351.
