[bhkuk]

 i want to create oxidation of 1,2:5,6-Diisopropylidene-D-mannitol with sodium metaperiodate in the presence of Aq.Sat Sodium bicarbonate to create 2,3-O-Isopropylidene-D-glyceraldehyde .
i will give you ditails of the procedure:
1. my solvent is dichloromethane there i put  1,2:5,6-Diisopropylidene-D-mannitol , i bring them to reflux, after it i am cooling it down,and adding Celite and then i vacuum-filter it through a pad of Celite.
2.after filtrating i put in saturated sodium bicarbonate following by sodium metaperiodate and then it should be swallow for 2 hours
3. after stirring i put in magnesium sulfate and again doing vaccum filtration
4.after it i keep cleaning my material by distillations
the first distilation is with Vigre condenser to let out my solvent, later i make distillation under vaccum to get monomer, and after it i should do another distillation with short Vigre condenser.
why should i use the Vigre condenser in this case?