| 摘要 |
Dihydroperoxides are made by oxidation of dialkyl aromatic hydrocarbons of the formula <FORM:0981707/C2/1> wherein Ar is an arylene group and R1, R2, R3 and R4 are alkyl groups, by contacting the dialkyl aromatic hydrocarbon with molecular oxygen, subjecting the oxidate which contains the monohydroperoxide and dihydroperoxide of the dialkyl aromatic hydrocarbon to extraction with an aqueous solution of an alkali metal hydroxide to remove the dihydroperoxide, treating the resultant organic phase which is substantially free from dihydroperoxide with gaseous carbon dioxide, washing the so treated organic phase with water, and recycling the washed organic phase to the oxidation stage. Preferred hydrocarbons are m- and p-diisopropylbenzenes. The oxidation is preferably effected at a pH within the range from 3 to 7 using molecular oxygen either alone or diluted with nitrogen at temperatures in the range from 50 DEG to 150 DEG C. The alkali may be sodium hydroxide or potassium hydroxide preferable in an aqueous solu containing 1 to 12% by weight of alkali metal hydroxide. The treatment of the organic phase with carbon dioxide may be carried out at temperatures ranging from 15 DEG to 80 DEG C. at least sufficient CO2 being employed to neutralize the alkali content. The gas may be introduced through suitable distribution apparatus and preferably the organic phase and carbon dioxide are passed in countercurrent flow through a packed column. The treated organic phase is washed with water to remove salts, the washing being effected after, or simultaneously with, the CO2 treatment. Thus the water may be fed in with the organic phase at the top of a scrubbing column wherein CO2 passes in countercurrent flow. The separation of the phases after the alkali extraction, and the separation of the aqueous salt solution from the organic phase after washing, may be effected by centrifuging. Detailed examples are given and the effect of neutralizing the organic phase with CO2 is compared with neutralization using sodium sulphate containing sulphuric acid or buffered sodium phosphate solution.
|
