It is {HEAD ~ an object} of the present invention to provide {TAIL ~ a high conversion} of isobutylene contained in a mixture of isomeric butenes simultaneously with a reduced yield of by products sec.butylphenols 
to provide
It is { HEAD ~ an object } of the present invention to provide { TAIL ~ a high conversion } of isobutylene contained in a mixture of isomeric butenes simultaneously with a reduced yield of by products sec.butylphenols
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH