Why anhydrous ether in grignard

This would form a hydrocarbon. But Grignard reagents are stable in ethers. The formation of ions in very nonpolar solvents, where they would not be effectively solvated is very difficult. To prevent the ether from boiling away, wrap a damp paper towel around neck of the Claisen adapter. It is important to control the addition of bromobenzene to avoid the rapid evolution of heat. After boiling slows, add a magnetic stir bar to the reaction tube and stir.

The reaction is complete when none of the magnesium remains. If the level of the ether has decreased, add more. In order prevent decomposition of the Grignard reagent it will be used immediately in the solution that it is in; there is no isolation or purification of the phenylmagnesium bromide.

In an oven dried vial, dissolve benzophenone mg, 2 mmol in 1 mL of anhydrous ether. With a dry 1 mL syringe, slowly add the solution to the reaction vessel containing the Grignard reagent, thus maintaining a gentle reflux. Rinse the benzophenone vial with a small amount of anhydrous ether and add this to the reaction tube also.

Vent the reaction vessel with a needle as necessary to release pressure. Allow the reaction mixture to stand at room temperature and observe a color change. The reaction is complete when the red color disappears. When the reaction is complete, cool the tube in ice and add to it drop wise with stirring 2 mL of 3M HCl. It may be necessary to transfer the reaction mixture to a larger container before completing the addition.

As the acid is added the triphenylmethanol will separate from solution as a white precipitate. Add additional ether to re-dissolve all of the precipitate, it need not be anhydrous. Remove the aqueous layer using a pipette and add an equal volume of saturated aqueous sodium chloride solution brine to the diethyl ether layer. Remove the aqueous layer and dry the ether layer by adding anhydrous calcium chloride until the drying agent no longer clumps.

What is an alkane? What is the formula of the ethyl group? What is a functional group in organic chemistry? See all questions in Definition of 'Chemistry' and 'Organic'. Impact of this question views around the world. The mixture first turns milky, then greenish and finally brown. In addition, the mixture should start to boil because the formation of the Grignard reagent is exothermic.

The two-necked or three-necked flask is heated with a warm water bath not directly on the hotplate or with a heat gun. The addition of the ethereal bromobenzene solution has to be carried out in a way that the reaction maintains a gentle boil.

A slow addition also reduces the temperature in the reaction and suppresses the formation of biphenyl because the formation of the Grignard reagent is favored at lower temperatures.