AIR OXIDATION OF CYCLOHEXANE WITH CONTROLLED FORMATION AND DECOMPOSITION OF CYCLOHEXYLHYDROPROPEROXIDE

摘要

1353225 Oxidation of cyclohexane E I DU PONT DE NEMOURS & CO 29 July 1971 [31 July 1970] 35750/71 Heading C2C The invention comprises a process for oxidation of cyclohexane to provide a liquid product containing cyclohexane, cyclohexanol, cyclohexanone and cyclohexyl hydroperoxide by passing a stream of liquid cyclohexane containing dissolved therein 0À1-5 p.p.m. of a soluble cobalt oxidation catalyst downwardly through a zoned reactor 22 (supplied from 24) in countercurrent contact with an upwardly flowing gas stream containing molecular oxygen (supplied at 42), wherein the liquid passes initially through at least one oxygen clean-up zone at 130-180‹ C./60-350 p.s.i.g. in which the molecular O 2 content is reduced to a level below that at which the subsequent removal of cyclohexane vapour produces an explosive mixture, and the liquid then passes through a series of oxidizing zones at 140-170‹ C./60- 350 p.s.i.g. wherein the molecular O 2 content is maintained in excess of the stoichiometric amount required by introduction of additional amounts of said molecular O 2 containing gas into each of said zones, the overall amount of molecular oxygen consumed in the oxidizing zones being not more than 95% of the total amount fed to the reactor, The liquid stream is withdrawn from the reactor from below the lowest oxidizing zone (via line 44), the amount of cyclohexylhydroperoxide in the product being at least 15% wt. based on the combined weight of cyclohexanol, cyclohexanone and cyclohexylhydroperoxide. In the illustrated apparatus zones are formed by the introduction of perforated trays 1-21, regions 26-41 are preferably oxidizing zones to which oxidizing gas may be admitted and off gas from 25 may be recycled to 42 to provide mild oxidizing conditions and strip cyclohexane from the product. Cobalt naphthenate is a specified catalyst.