A well-known method for the production of phenol and acetone by oxidation of cumene with atmospheric oxygen, followed by the acid-catalytic decomposition of cumene hydroperoxide, permits both end products to be produced with high yield (see, for example, Kruzhalov B. D., Golovanenko B. N., Combined Production of Phenol and Acetone, Moscow, Goskhimizdat, 1964, or Kirk-Othmer Encyclopedia of Industrial Chemistry). The method is widely used to produce these products and is the principal technique used in world practice.
Strategies for increasing productivity in processes for the conversion of cumene hydroperoxide to phenol and acetone include reduction of unwanted side products. Methods are known for producing phenol and acetone in which, to reduce the yield of phenol tar, cumene oxidation products containing cumene hydroperoxide (CHP), cumene, and dimethylbenzyl alchohol (DMBA) are cleaved in the presence of sulfuric acid. In a first stage, at a temperature of 55 to 80° C., most of the CHP (97 to 99%) is decomposed and dicumyl peroxide (DCP) is produced from DMBA and CHP. In a second stage, acetone is added at a temperature from 80 to 146° C. to the obtained reaction mixture containing phenol, acetone, dimethylbenzyl alcohol (DMBA) and dicumyl peroxide (DCP). The addition is made in an amount of 1.5 to 1.8 times the original concentration of acetone. Water is also added. In some cases the acid is partially neutralized with ammonia before the second separation stage in order to ensure optimal acidity of the catalyst. After breakdown of DCP formed in the first stage, decomposition of the remaining CHP and dehydration of the remaining DMBA occur at a temperature from 80 to 146° C.
While strategies directed to increased productivity by producing higher yields of desired products are known in the art, commercial processes for the decomposition of cumene hydroperoxide still result in a build-up of a fouling precipitate which can coat interior surfaces of reactors. This build-up of unwanted precipitate or residue results in operational problems and decreased productivity. There is a need in the art for a process that, in addition to producing high yields of desired products, avoids build-up of unwanted precipitates in the production equipment.
USPTO Backgrounds
USPTO Backgrounds