Abstract: 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 KLa/Q>10, where KLa is the total volumetric mass transfer coefficient and Q is the heat load liberated by the reaction per mole of glyoxal.

Abstract: 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?1 group, and R1, R2, R3 and R?1 independently represent an alkyl or aralkyl group.

Abstract: 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.

Abstract: 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.

Abstract: 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 KLa/Q>10, where KLa is the total volumetric mass transfer coefficient and Q is the heat load liberated by the reaction per mole of glyoxal.

Abstract: 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 aluminium halide and of a tertiary amine of a compound of formula (II)-(E) or (II)-(Z) in which A represents hydrogen or an OR?1 group, and R1, R2, R3 and R?1 independently represent an alkyl or aralkyl group.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: The invention relates to a method for separating a diacetal of the glyoxal of a raw mixture comprising said diacetal of the glyoxal and a monoacetal of the glyoxal, by means of counter-current liquid-liquid extraction.

Abstract: A product corresponding to formula (I) or its ketonic tautomer form (II) which is 3-(1-hydroxy-pentylidene)-5-nitro-3H-benzofuran-2-one, a process for the preparation and use of the product corresponding to formula (I) or its tautomeric form (II), a process for the preparation and use, particularly for the production of synthesis intermediates.

Abstract: A product corresponding to formula (I) or its ketonic tautomer form (II) 1

Abstract: 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):--CHR.sub.1 --(CR.sub.2 R.sub.3).sub.n --CHR.sub.4 -- (II)in which R.sub.1, R.sub.2, R.sub.3 and R.sub.4, identical or different, represent a hydrogen atom or an alkyl radical containing 1 to 4 carbon atoms and n represents 0 or 1, in their different stereoisomer forms, their preparation process and their use.

Abstract: 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):--CHR.sub.3 .paren open-st.CR.sub.4 R.sub.5 .paren close-st..sub.n CHR.sub.6 -- (II)in which R.sub.3, R.sub.4, R.sub.5 and R.sub.6, identical or different, represent a hydrogen atom or a C.sub.1 -C.sub.4 alkyl radical, and n represents 0 or 1, in which an aqueous mixture of glyoxal and an ethanal of formula (III): ##STR2## in which R.sub.1 and R.sub.2 have the meaning given above, is reacted with ammonia.

Abstract: 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):--CHR.sub.1 --(CR.sub.2 R.sub.3).sub.n --CHR.sub.4 -- (II)in which R.sub.1, R.sub.2, R.sub.3 and R.sub.4, identical or different, represent a hydrogen atom or an alkyl radical containing 1 to 4 carbon atoms and n represents 0 or 1, in their different stereoisomer forms, their preparation process and their use.

Abstract: Sodium salt of 1-menthyloxycarbonyl 1-hydroxy methanesulphonic acid, its preparation process and its use for obtaining L(-)menthyl glyoxylate.Product of formula (I).

Abstract: 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).

Abstract: 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.

Abstract: 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.

Abstract: 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.