METHOD FOR THE HYDROXYLATION OF PHENOLS AND PHENOL ETHERS

摘要

The present invention relates to a method for the hydroxylation of phenols and phenol ethers by means of hydrogen peroxide. The invention specifically relates to a method for the hydroxylation of phenol by means of the hydrogen peroxide. The method of the invention for the hydroxylation of a phenol ether by means of reacting said phenol or phenol ether with the hydrogen peroxide in the presence of an acid catalyst is characterized in that it includes mixing a phenol or phenol ether with a hydrogen peroxide solution in a mixing device under conditions enabling the conversion rate of the hydrogen peroxide to be minimized, and in that said reaction mixture is then placed in a piston flow reactor where the reaction leading to the production of the hydroxylated material takes place, the acid catalyst being fed into the mixing device and/or into the piston flow reactor.

主权项

1. A process for the hydroxylation of a phenol or of a phenol ether, the process comprising:
mixing a phenol or phenol ether with a hydrogen peroxide solution to form a reaction mixture in a mixing device under conditions such that the degree of conversion of the hydrogen peroxide is minimized; introducing said reaction mixture into a piston-flow reactor in which takes place the reaction leading to the formation of a hydroxylated product; and introducing a strong protic acid catalyst having a pKa in water of less than −0.1 into the mixing device and/or into the piston-flow reactor.