reacting {HEAD ~ the cellulose activate} with an acetylating agent in {TAIL ~ the presence} of the acetylating catalyst and acetylating solvent, 
reacting { HEAD ~ the cellulose activate } with an acetylating agent in { TAIL ~ the presence } of the acetylating catalyst and acetylating solvent ,
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH