Separation of close boiling phenols and naphthols through their selective etherification with isobutylene / isoamylene acidic ion exchange resin as catalyst

Abstract

The etherification of phenol and substituted phenols, such as o-chlorophenol, o-ethylphenol and guaiacol and α- and β-naphthols with isobutylene and isoamylene was studied. The etherification was carried out in the presence of an acidic ion exchange resin, Amberlyst 15, as a catalyst and in the temperature range of 5 to 30°C. The relative rates of etherification of phenol / o-chlorophenol, o-ethylphenol / guaiacol and α-naphthol / β-naphthol were measured. A novel separation strategy, based on selectived etherification and subsequent cracking of tert-buryl / tert-amyl ethers, was successfully applied for the close boiling phenols and naphthols. The purification of β-naphthol containing α-naphthol impurity through the selective acid catalysed C-alkylation of α-naphthol with isobutylene and isoamylene was also found to be succesful.