Question

What is trituration in a Grignard Reaction and why is it necessary to break lumps of solid during trituration?

Answer 1

Trituration is a purification process used in Grignard (or for that matter, any organic) synthesis. In trituration, a solvent is chosen such that the organic solid synthesized is insoluble in the solvent while the impurities are soluble. It may be possible to affect trituration by choosing a solvent such that the solid is highly soluble in the solvent while the impurities are insoluble. The crude solid is washed with this solvent several times. The solid separates out from the solvent and can be collected by vaccum filtration and dried to obtain a purified compound.

It is important to add the solvent to the crude compound and break u or mash the crude compound with a spatula or a glass rod. This increases the surface area of the solid and therefore, improves the ability of the solid to separate out from the solution as a precipitate.