Rhodia Operations

Stéphanie Normand

Laurent Garel

Jean-Christophe Bigouraux

Pascal Pitiot

Dominique Horbez

Stephanie Foucher

Stéphanie Foucher

Morad Assam

The invention describes a method for separating a mandelic compound in salified form from an aqueous reaction medium resulting from the condensation reaction of a hydroxylated aromatic compound with glyoxylic acid in a basic medium, said method comprising a) decanting said reaction medium in such a way as to recover an organic phase formed from the excess of said aromatic compound and an aqueous phase formed from said mandelic compound and a quantity of the excess of said aromatic compound and b) bringing said aqueous phase into contact with an adsorbent support, resulting in the selective adsorption of said aromatic compound and the recovery of an aqueous flow comprising said mandelic compound in salified form, which is subjected to an oxidation step before being converted into hydroxyaromatic aldehyde by electrodialysis.

Method for separating mandelic compounds in salified form and use of same for preparing aromatic aldehyde

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 or 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.

Method for the hydroxylation of phenols and phenol ethers

A method for hydroxylating phenols and phenol ethers using hydrogen peroxide and specifically, a method for hydroxylating phenol using hydrogen peroxide. The method for hydroxylating a phenolic substrate selected from a phenol or a phenol ether by reacting such phenolic substrate with hydrogen peroxide in the presence of an acid catalyst comprises the following steps, implemented consecutively or simultaneously: a first step consisting of mixing a phenolic substrate with a hydrogen peroxide solution under conditions in which the temperature is sufficient for the initial phenolic substrate to remain liquid and for minimizing the conversion rate of the hydrogen peroxide; a second step consisting of carrying out the phenolic substrate hydroxylation reaction under adiabatic conditions, the acid catalyst being added at the mixing stage and/or at the beginning of the hydroxylation reaction; and a third step, if necessary, consisting of recovering the hydroxylated product.

Method for hydroxylating phenols and phenol ethers

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Saint Genis Laval, France

Stéphanie Normand