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