METHOD OF FREEING PHENOL FROM ACETOL Russian patent published in 2005 - IPC

FIELD: industrial organic synthesis.

SUBSTANCE: invention relates to production of phenol via acid catalytic decomposition of cumene hydroperoxide followed by isolation of phenol from decomposition products and purification of phenol to remove trace impurities including acetol. Purification of phenol is accomplished through hetero-azeotropic rectification with water. Acetol is isolated as a part of liquid-phase side stream from semiblind plate located within exhausting section of hetero-azeotropic rectification column. Side stream is supplemented by cumene and used to supply stripping column, from which fraction of acetol/cumene azeotropic mixture is taken as distillate and residue is returned under semiblind plate of hetero-azeotropic rectification column to be further exhausted. From the bottom of the latter, crude phenol is withdrawn and passed to final purification from the rest of reactive trace impurities. Acetol/cumene azeotropic mixture is subjected to heat treatment at 310-350°C, which may be performed in mixtures with high-boiling production waste or in mixtures with bottom product of rectification column for thermal degradation of high-boiling synthesis by-products, which bottom product is recycled via tubular furnace. Above-mentioned semiblind plate, from which side stream is tapped, is disposed in column zone, wherein content of water is minimal and below which contact devices are positioned with efficiency at least 7.5 theoretical plates. Side stream with cumene added to it is passed to the vat of stripping column with efficiency at least 15 theoretical plates.

EFFECT: minimized content of acetol in purified phenol and reduced power consumption.

5 cl, 3 dwg, 6 tbl, 4 ex