GB463036A - Improved manufacture of alkyl phenols and related compounds - Google Patents

Abstract

Alkylphenols, hydroxyarylmethanes and xanthenes are obtained when phenol-formaldehyde condensation products are subjected to destructive distillation or pyrolysis, if desired in presence of a surface catalyst such as fuller's earth. Before the pyrolysis, a preliminary distillation may be effected, preferably under vacuum, to remove unchanged phenols and separate the hydroxyarylmethanes. The alkylphenols and xanthenes are produced by the pyrolysis treatment which is effected at normal pressure. The starting materials may be prepared from monohydroxyphenols such as phenol, cresols and xylenols, or from polyhydroxyphenols, which are condensed with formaldehyde in varied proportions and in presence of basic or acidic catalysts. According to the examples: (1) equimolecular parts of m-cresol and formaldehyde are condensed in the presence of formic acid and subjected first to vacuum distillation under 17 mm. of mercury and then to pyrolytic distillation at about 450 DEG C. under normal pressure; the vacuum distillate consisted of unchanged m-cresol and at least three isomers of dihydroxyditolylmethane; the acidic portion of the pyrolytic distillate contained m-cresol, o-4-xylenol, p-xylenol and pseudo-cumenol, whilst from the neutral portion 3 : 6-dimethylxanthene was isolated; (2) a resin prepared by condensing 4 mols. of m-5-xylenol with 6 mols. formaldehyde in presence of hydrochloric acid was treated as in (1); the vacuum distillate contained three isomers of dihydroxydixylylmethane, the acidic portion of the pyrolytic distillate yielded iso-pseudo-cumenol and durenol, and the neutral portion of the pyrolytic distillate a tetramethylxanthene; (3) various phenols, including o-4-xylenol and p-xylenol, were obtained by the pyrolysis at 450 DEG C. of a m-cresol-formaldehyde resin prepared p under ammoniacal conditions; (4) a resin prepared from equimolecular amounts of o-cresol and formaldehyde in the presence of hydrochloric acid yielded on vacuum distillation at 24 mm. two isomers of dihydroxyditolylmethane and on further pyrolytic treatment at 450 DEG C. an oily distillate, the acidic portion of which contained mesitol. It is also stated that a phenol-formaldehyde condensation product yields o- and p-cresols, as well as 4 : 4<1>- and 2 : 4<1>-dihydroxydiphenylmethanes, and that a p-cresol-formaldehyde condensation product gives rise to 2 : 7-dimethylxanthene and 2 : 2<1>-dihydroxy-5 : 5<1>-dimethyldiphenylmethane. The residue remaining after pyrolysis may be extracted with solvents such as nitrobenzene and cumene.