Why Use Methanol and Ether for Washing in Synthesis?

[Shadowz]

I read many procedure for inorganic/organic synthesis, and see that most often after filtering the product, they suggest to wash them with small amount of methanol and ethyl ether.

Why do we have to use those 2 solvents to wash our products?

 

[gravenewworld]

I read many procedure for inorganic/organic synthesis, and see that most often after filtering the product, they suggest to wash them with small amount of methanol and ethyl ether.

Why do we have to use those 2 solvents to wash our products?

you wash your products with solvents that they are not soluble in in order to purify them. on the other hand, if you are filtering out stuff you don't want, you wash what you filter off with a solvent that will dissolve your desired product in order maximize your yields. methanol and ether are excellent solvents a lot of times for organic sythesis.

 

[Shadowz]

That's the basic idea. But I wonder why it has to be methanol and dimethyl ether, but not other organic solvents.

 

[symbolipoint]

I read many procedure for inorganic/organic synthesis, and see that most often after filtering the product, they suggest to wash them with small amount of methanol and ethyl ether.

Why do we have to use those 2 solvents to wash our products?

Which compound description do you mean? Inorganic, or Organic? Maybe some inorganic compounds are fairly insoluble in methanol or ethyl ether. Best guess is that many or most organic compound may be soluble in methanol or ethyl ether; salts are likely insoluble in the organic solvents (is this a bad assumption?)

 

[gravenewworld]

Which compound description do you mean? Inorganic, or Organic? Maybe some inorganic compounds are fairly insoluble in methanol or ethyl ether. Best guess is that many or most organic compound may be soluble in methanol or ethyl ether; salts are likely insoluble in the organic solvents (is this a bad assumption?)

No. That is a good assumption. A lot of inorganic impurities can be removed from a filtering+organic solvent wash. Methanol and ether are excellent solvents for organic compounds a lot of times.

That's the basic idea. But I wonder why it has to be methanol and dimethyl ether, but not other organic solvents.

It doesn't have to be strictly methanol or ether. You could use solvents like ethyl acetate or DCM as well. Methanol and ether are used a lot of times because they are easy to evaporate off and dissolve a lot of organic compounds. Methanol and ether are also extremely easy to spot by NMR and also don't show up on things like the UV spectra in a LC/MS which makes identification of what you have much easier.