Ortho-phenyl phenol prodn - by catalytic dehydrogenation of cyclohexanone intramolecular condensation product

摘要

o-Phenylphenol (which is used e.g. as an intermediate for dyes, photographic chemicals and rubber chemicals and as a low-toxicity fungicide) is produced quantitatively by feeding the prodt. of the bimolecular dehydration-condensation of cyclohexanone (a mixture of 2-(1-cyclohexenyl)-cyclohexanone and 2-cyclohexylidene-cyclohexanone) to a bed of catalyst (deposited on an inert carrier) and subjecting it to dehydrogenation at 23-520 degrees C in the presence of an inert gas (pref. H2, He, N2 or steam). The dehydrogenation catalyst is pref. produced by depositing small amts. (pref. 0.05-5 wt.%) of Pd, Pt, Ir and/or Rh on a carrier such as silicaceous earth, alumina or active charcoal and adding a suitable amt of an alkali (pref. NaOH, KOH, LiOH or Ba(OH)2).