Ortho-phenyl phenols prepn. by condensing cylohexanone - and dehydrogenating cyclohexenyl cyclohexanone with metal catalyst in presence of sulphur

摘要

O-phenyl phenols are prepd. by (a) condensing a cyclohexanone using a condensation catalyst other than a naphthenate to form a mixt. contg. o-cyclohexenyl cyclohexanone (I), (b) recoverin (I) and (c) dehydrogenating (I) by contacting it with a Ru, Rh, Os, Ir, Pt or Pd met al dehydrogenation catalyst and sulphur, or an organo-sulphide or thiol, the sulphur/dehydrogenation catalyst metal wt. ratio being 1/60 to 1/12. The presence of the sulphur improves the selectivity of the dehydrogenation catalyst in favour of o-phenyl phenol. In an example, 5.52 ppm total sulphur increased the yield of o-phenyl phenol from 58.7% to >98%.