The resulting mixture is then stirred and optionally heated over {HEAD ~ a sufficient period} of {TAIL ~ time} to bring about formation of the dye product 
of
The resulting mixture is then stirred and optionally heated over { HEAD ~ a sufficient period } of { TAIL ~ time } to bring about formation of the dye product
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH