碘甲烷做格氏试剂？ 活泼的卤代烷（如溴苄，碘甲烷allyl br 等）的格氏试剂不能用thf作为溶剂来制备只能用乙醚，因为它们的thf溶液活性高容易发生自身偶合反应，它们的thf溶液可由乙醚溶液交换而得，具体做法如下（allylmagnesium bromide / thf）： a dry, 3-l, three-necked, round-bottomed flask is equipped with a sealed mechanical stirrer 500-ml, pressure-equalizing, dropping funnel and a reflux condenser, the top of which is connected to a calcium chloride drying tube. the flask is charged with a large excess of magnesium turnings (90.00 g, 3.75 g-atom) and 150 ml of dry diethyl ether. to the stirred mixture is added dropwise a solution of allyl bromide (181.60 g, 1.50 mol) in 1.5 l of dry diethyl ether. at the end of the addition (8 hr) the mixture is stirred for 1 hr, whereupon the grignard reagent solution is transferred under nitrogen, with a cannula, into a 2-l, two-necked, round-bottomed flask equipped with a 500-ml dropping funnel and a reflux condenser fitted with a swan neck (distillation) adapter connected with a descending condenser. after removal of the water in the vertical reflux condenser, the solution of the grignard reagent is heated with a water-bath (45°c, then progressively up to 65°c) with stirring to remove the uncomplexed diethyl ether (2 hr). dry tetrahydrofuran (thf, 500 ml) is added rapidly (10 min) to the gray pasty residue. a vigorous reaction occurs, and the decomplexed diethyl ether is easily removed by distillation. the reaction is completed by heating the mixture with stirring for 1 hr to give a fluid gray thf solution of allylmagnesium bromide. 大家不妨一试，我没作过mei，但苄氯和苄溴的差别我是试过的，用苄溴，thf作为溶剂就是得不到东西，呵呵。查看更多
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