[rcmishra]

Here I see a mechanism of Acetonide protection of Diols:
Explained as follows:

In the first step acetone gets protonated so that lone pair of Oxygen atom from the hydroxy group can attack the electron deficient carbonyl carbon. Next, a molecule of water is eliminated creating a slightly positive charge on oxygen atom. Again, polarization of C-O bond occurs and the lone pair of the oxygen atom from other hydroxyl group attacks the carbon forming a C-O bond and acquiring slightly positive charge. In the final step the extra proton is eliminated and hydroxyl groups get protected as acetonide.

http://neochemist.com/mechanisms/mechanism-of-acetonide-formation-i-using-acetone-as-reagent/

I have seen some people using a acetone as solvent and Dimethoxy propane as reagent for the same reaction. In my opinion DMP is good when you are not using acetone, but in case you are using acetone, the reaction utilizes Acetone not the Dimethoxy propane for the acetonide formation.

What you guys say?

[Dan]

Hint: The reaction is reversible, DMP can serve another useful function....