METHOD FOR SYNTHESISING CYCLOHEXANONE Russian patent published in 2021 - IPC C07C45/33 C07C45/00 C07C49/403 

FIELD: chemistry.

SUBSTANCE: present invention relates to a method for producing cyclohexanone by liquid-phase catalytic oxidation of cyclohexane with air oxygen at a temperature of 120 to 160°C and a pressure of 1 to 2 MPa in the presence of a solution of cobalt naphthenate in cyclohexane oxidation products as a catalyst with a concentration of cobalt of 0.1 to 0.006 wt.% in the presence of sodium bromide as an initiator at a molar ratio [sodium bromide]:[cobalt naphthenate] equal to 1:5 to 1:10 in a four-section bubbling reactor, introducing a catalyst into the first section of the bubbling reactor in the course of the process flow, introducing sodium bromide into the second, third and fourth sections of the reactor, evaporating the cyclohexane, condensing in a refrigerator, isolating cyclohexane from the gaseous phase in a separator and returning cyclohexane to the oxidation stage, producing an oxidate in the last section of the bubbling reactor, washing the oxidate with water resulting in an aqueous layer and an organic layer, separating the organic layer from the aqueous layer by separation, rectifying the organic layer resulting in cyclohexane, returned to the oxidation stage, and bottoms-1, treated by heating in a cascade of apparatuses with stirrers by aqueous alkali, producing an aqueous alkaline layer and an organic layer, separating the aqueous alkaline layer from the organic layer by separation and rectifying the organic layer resulting in cyclohexane, returned to the oxidation stage, and bottoms-2, containing primarily cyclohexanol and cyclohexanone. Bottoms-2 are therein subjected to catalytic dehydrogenation at a temperature of 220 to 270°C, producing a mixture of cyclohexanol and cyclohexanone with a high content of cyclohexanone, rectification of the mixture in a complex rectification column results in production of cyclohexanone as distillate, partially used to prepare the catalyst, conduct side selection of the intermediate fraction, and bottoms-4 constituting high-boiling products sent for recycling, and rectification of the intermediate fraction in the side rectification column results in production of a distillate, sent to the upper part of the complex rectification column as additional irrigation, and bottoms-3, directed to the dehydrogenation stage.

EFFECT: proposed method provides a possibility of increasing the yield of the target product, simplifying the technology and reducing the power consumption.

2 cl, 2 dwg, 1 tbl, 8 ex