Societe Francaise Hoechst

Clariant Specialty Fine Chemicals (france)

Nobel Hoechst Chimie

Clariant (france) Sa

Clariant (france)

Clariant Speciality Fine Chemicals (france)

501 Societe Francaise Hoechst

Clariant Specialty Fine Chemicals

Weylchem Lamotte

Alain Schouteeten

Yani Christidis

Jean-Claude Vallejos

François Bleger

Sébastien Jus

Didier Wilhelm

Olivier Simon

Jean-Michel Alarcon

Claude Cathelineau

Françoise Mordacq

Jérôme Piron

Fran&ccedil;oise Mordacq

Gilles Dressaire

Sebastien Jus

Sébastian Jus

The invention relates to a method for preparing an aqueous solution of glyoxylic acid by oxidation of an aqueous solution of glyoxal with oxygen or a gas containing oxygen, in the presence of a catalytic quantity of nitric acid and/or at least one nitrogen oxide, a strong acid not oxidizing glyoxal, and by maintaining conditions satisfying the equation Ka/Q&#x3e;10, where Ka is the total volumetric mass transfer coefficient and Q is the heat load liberated by the reaction per mole of glyoxal.

Process of preparation of glyoxylic acid aqueous solution

The invention relates to a process for the synthesis of stilbene derivatives of formula (I)-(E) or (I)-(Z) in which R represents hydrogen or an OH group,by deprotection in the presence of an aluminum halide and of a tertiary amine of a compound of formula (II)-(E) or (II)-(Z) in which A represents hydrogen or an OR'group, and R, R, Rand R&#x2032;independently represent an alkyl or aralkyl group.

Process for the synthesis of polyhydroxystilbene compounds

The invention relates to the use of metal complexes comprising a ligand derived from 2-aryl-2-hydroxyacetic acid and a divalent or trivalent metal cation and to the use of the said ligands in dissolving divalent or trivalent metal cations in aqueous phase. The said complexes can be used to treat metal deficiencies in plants.

Metal complexes comprising a ligand derived from 2-aryl-2-hydroxyacetic acid and a divalent or trivalent metal cation, and their use

A subject-matter of the present invention is a novel process for the synthesis of (E)-stilbene derivatives targeted at obtaining in particular resveratrol and piceatannol.

Process for the synthesis of (E)-stilbene derivatives which makes it possible to obtain resveratrol and piceatannol

Process for the preparation of a 2-(n-alkyl)-3-(4-hydroxybenzoyl)benzofuran of formula (I) in which R represents a linear or branched alkyl radical including from 1 to 5 carbon atoms and R1 represents a linear or branched alkyl radical including from 1 to 3 carbon atoms, a linear or branched alkoxy radical including from 1 to 3 carbon atoms, a halogen atom or a nitro radical, and intermediates.

Process for the preparation of n-alkyl-2(hydroxy-4benzoyl)-3 benzofurans and intermediates thereof

3-(1-hydroxy-pentylidene)-5-nitro-3H-benzofuran-2-one a process for the preparation thereof and the use thereof

Azines of formula (I): ##STR1## in which R and R' either are identical and represent an alkyl radical containing 1 to 4 carbon atoms or an alkenyl radical containing 3 to 5 carbon atoms, or together form a radical of formula (II):

Acetaldehyde derivatives, their preparation process and their use

Preparation process for a product of formula (I): ##STR1## in which R.sub.1 and R.sub.2, either are identical and represent a C.sub.1 -C.sub.4 alkyl radical, or form together a group of formula (II):

Preparation process for 2 formyl imidazole acetals

Sodium salt of 1-menthyloxycarbonyl 1-hydroxy methanesulphonic acid, its preparation process and its use for obtaining L(-)menthyl glyoxylate. Product of formula (I). ##STR1## preparation process and use of the product of formula (I) according to claim 1 for obtaining the product of formula (II)

Sodium salt of 1-menthyloxycarbonyl 1-hydroxy methanesulphonic acid, its

Product of formula (I) ##STR1## preparation process and use of the product of formula (I) according to claim 1 for obtaining the product of formula (II).

Process for the continuous preparation of dimethoxy ethanal (DME) in which a 70% by weight of an aqueous solution of glyoxal is continuously reacted with 8 to 12 moles of methanol/mole of glyoxal in the presence of a cation exchange resin, then the reaction solution obtained is subjected to an initial distillation, at atmospheric pressure, in order to recover more than 90% of the unreacted methanol, which is recycled, then to a second distillation under a pressure of less than 10.+-.2 kPa in order to isolate an aqueous mixture containing the greater part of DME and 1,1,2,2-tetramethoxyethane (TME) formed. This mixture, after dilution with water (molar ratio of water/TME 29.+-.4), is subjected to a distillation under a pressure of less than 19 kPa in order to remove from the top fraction an aqueous mixture containing more than 98.5% of the TME present and to also obtain an aqueous solution of DME having a purity greater than 98.5%, and that, at the same time as these operations, the aqueous mixture containing the TME as well as the bottom fraction of the distillation produced from the distillation column of aqueous mixture containing the greater part of DME and TME, is treated continuously while warm, in the presence of a cation exchange resin, in order to obtain a water-methanol-glyoxal mixture, the methanol of which is evaporated off and recycled with the methanol recovered previously, before recycling half of it with the starting aqueous glyoxal solution after having been concentrated and recycling half with the aqueous mixture containing the TME.

Continuous process for the industrial manufacture of dimethoxyethanal

Preparation process for orthohydroxymandelic acid, as well as its salts, in which glyoxylic acid is reacted with phenol in the presence of a tertiary amine and catalytic quantities of trivalent metal cations, in order to obtain the expected product which is isolated and, if desired, salified.

Process for obtaining orthohydroxymandelic acid and its salts

Continuous manufacturing process for an aqueous solution of glyoxylic acid by nitric oxidation of an aqueous solution of glyoxal carried out in the presence of hydrochloric acid in which the oxidation is effected continuously using 0.80.+-.0.2 mole of nitric acid and 0.70.+-.0.05 mole of hydrochloric acid per mole of glyoxal in a reaction medium having a concentration by weight between 5 and 6% of hydrochloric acid and higher than 10% of nitric acid.

New continuous industrial manufacturing process for an aqueous solution

The invention relates to the preparation of glyoxylic acid by oxidizing an aqueous solution of glyoxal having a pH less than 1 with molecular oxygen in the presence of nitrogen monoxide as a catalyst. This process allows the practically total conversion of the starting glyoxal with a good yield of glyoxylic acid.

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Ezanville, France

Alain Schouteeten