Purification of phenol with reduced energy consumption

摘要

Phenol (10) produced by the cleavage of cumene hydroperoxide is chemically treated with a base (12) such as a polyamine, is optionally then treated with an acid or acid anhydride (15) such as phthalic anhydride, is then steamed distilled (12) to remove a lites fraction as a water azeotrope (21) and the bottoms (34) of the steam distillation are vacuum distilled (35) to recover high purity phenol (36) as an overhead. The overheads (21) of the steam distillation are condensed (22) and may be phase separated (23) into an aqueous phase (25) and organic phase (24), with the aqueous phase (25) mixed (26) with an organic solvent (27) which preferentially dissolves benzofuran impurities. This mixture is phase separated into an organic solvent phase (30, 130) and a recycle aqueous phase (31). Alternatively, the entire condensed overheads (21) may be extracted (146-151 and 153) with organic solvent. In some forms, the organic solvent phase (130) is washed with aqueous base (142) to remove phenol and impurities and the organic solvent (127) is regenerated for again mixing with the aqueous phase. In other forms the organic solvent is a portion (152) of the high purity phenol produce (36). This treatment and careful control of the chemical treatment to minimize formation of benzofuran impurities reduces the steam consumption of the steam distillation step, thereby producing high purity phenol with reduced energy consumption.