Have you tried heating under vacuum?  The best way of accomplishing that with a solid is by using an Abderhalden drying pistol.  That lets you use the heat of a refluxing solvent with no danger of overheating and decomposing your material.

Hi Vasu,

Try to wash with diethyl ether - the quaternary ammonium salts are not soluble in this solvent but the benzyl chloride is.

Thanks for Joseph S Merola and Marius Pelmus

This is product cost itself 90 rs . we are doing this operations means cost will go more than selling price .