It is fine although I usually get it in a pink tinge. 

But I doubt the azeotropic removes the water of crystallisation from PTSA probably just surface water

Use dean stark apparatus to remove water 

Make sure your line covered with aluminum foil and use toluene for it

I don't know what a roti is but if you are referring to rotavap, it won't do the job

You can use toluene for azeotropic removal of water from PTSA using rotary evaporator at 50-55 degree temperature. 

 Chenging a colour s not a problm it is normal. But to dry monohydrate to unhydrous form heatind at 50 0C is NOT enogh. And ordinary "distilling off" a benzene is not very effective. You need a prolonged refluxing with Dean- stark apparatus with WIGOROUSLY stirring becauce PTSA xH2O is poorly mixed with benzene while no more water distill. And monohydate is a powder with high melting point,  but an unhydrous PTSA is a dense mass-like clay. If you do dot see such changing - your PTSA is WET

Use a Dean Stark apparatus for the reaction using toluene as solvent.

take methylene chloride and carry out azeotropic distillation .it takes out water of crystallization from PTSA

Hi Pallavi,

Try prolonged refluxing with Dean- Stark apparatus with vigorously stirring.

Good luck,

Ramin