Abstract: The invention relates to novel dendritic polymers having monophosphonic terminations or dimethyl phosphonates, to a method for preparing them, and to their uses.

Abstract: The invention relates to novel dendritic polymers having biphosphonic terminations, to derivatives thereof, to a method for preparing them and to their uses.

Abstract: The invention relates to novel dendritic polymers having biphosphonic terminations, to derivatives thereof, to a method for preparing them and to their uses.

Abstract: The present invention relates to a process for the preparation of ?- or ?-unsaturated or saturated carboxylic acids. It relates more particularly to the hydroxycarbonylation of an organic compound comprising a conjugated unsaturation, such as butadiene, by the action of carbon monoxide and water in the presence of a palladium-based catalyst. The carboxylic acids thus obtained are preferably pentenoic acids. According to the invention, the reaction medium after the end of the hydroxycarbonylation stage is treated with hydrogen to reduce the palladium present in the 2+ oxidation state to palladium in the zero oxidation state and the precipitated palladium is recovered.

Abstract: The present invention relates to a process for the preparation of &bgr;- or &ggr;-unsaturated or saturated carboxylic acids.

Abstract: The present invention concerns a process for the preparation of a 2-hydroxybenzoic acid and of a 4-hydroxybenzaldehyde and derivatives thereof from a mixture of two phenolic compounds, one carrying a formyl or hydroxymethyl group in the 2 position, and the other carrying a formyl or hydroxymethyl group in the 4 position. The invention also concerns the preparation of a 4-hydroxybenzaldehyde from said mixture. The invention more particularly concerns the preparation of 3-methoxy-4-hydroxybenzaldehyde and of 3-ethoxy4-hydroxybenzaldehyde, respectively known as “vanillin” and ethylvanillin”.

Abstract: Dinitro aromatic compounds are improvedly prepared by reacting an aromatic compound with a nitric acid nitrating agent and thence separating the nitrating acid from the process stream thus formed, the process stream containing said at least one dinitro aromatic compound and also having a fraction of the nitrating acid dissolved therein, the subject process also comprising (a) distilling/stripping nitric acid from said process stream, (b) recovering nitric acid from the top of the distillation/stripping vessel and recycling same to the nitration reaction and (c) washing the process stream which contains the at least one dinitro aromatic compound, but having the nitric acid removed therefrom.

Abstract: The present invention concerns a process for the preparation of a 4-hydroxybenzaldehyde and its derivatives. More particularly, the invention concerns the preparation of 3-methoxy-4-hydroxybenzaldehyde and 3-ethoxy-4-hydroxybenzaldehyde, respectively known as vanillin and ethylvanillin.

Abstract: Picric acid, namely, 2,4,6-trinitrophenol, is readily and effectively prepared by nitrating o-nitrophenol and/or p-nitrophenol into at least one dinitrophenol in a nitric acid medium of reaction, characteristically essentially consisting of nitric acid or immixture thereof with a strong co-acid, the at least one dinitrophenol remaining soluble in the medium of reaction, and therein completing nitration of the at least one dinitrophenol and precipitating picric acid therefrom.

Abstract: Environmentally-polluting nitrocresol values are removed from admixtures of nitroaromatic compounds comprised thereof, notably the media of nitration of aromatic compounds by reacting same with aqueous HNO.sub.3 /H.sub.2 SO.sub.4, by first intimately contacting such nitroaromatic compound admixtures with an oxidizing agent comprising hydrogen peroxide, javelle water, or mixture thereof, and thereafter with a neutralizing agent; the nitroaromatic aromatic compounds thus purified are conveniently catalytically hydrogenated into aromatic amines.

Abstract: The present invention relates to a process for the preparation of carboxylic acids from unsaturated fatty acids and/or their derivatives.The process of the invention is characterized in that it comprises the following stages:a stage which consists in oxidizing an unsaturated fatty acid in the form of acid and/or of ester using hydrogen peroxide, in the presence of a metal oxide or of a carboxylic acid optionally used in combination with a ruthenium-based catalyst,a stage which consists in reacting the reaction mixture originating from the preceding stage with nitric acid in the presence of a vanadium-based catalyst, optionally used in combination with a cocatalyst, and thena stage of recovery of the mono- and dicarboxylic acids.It is particularly well suited for the preparation of saturated mono- and dicarboxylic acids obtained from unsaturated fatty acids such as oleic acid or from oils and fats.

Abstract: The present invention concerns a process for the preparation of 3-carboxy-4-hydroxybenzaldehydes and derivatives thereof from phenolic compounds carrying formyl and/or hydroxymethyl groups in the 2 and 4 positions.The invention also concerns the preparation of 4-hydroxybenzaldehydes from 3-carboxy-4-hydroxybenzaldehydes.More particularly, the invention concerns the preparation of 3-methoxy-4-hydroxybenzaldehyde and 3-ethoxy-4-hydroxybenzaldehyde, respectively known as "vanillin" and "ethylvanillin".The process for the preparation of 3-carboxy-4-hydroxybenzaldehyde is characterized in that the group in the 2 position in a phenolic compound carrying formyl and/or hydroxymethyl groups in the 2 and 4 positions is selectively oxidized to a carboxy group, and optionally a hydroxymethyl group in the 4 position is selectively oxidized to a formyl group.A successive decarboxylation step for a 3-carboxy-4-hydroxybenzaldehyde produces a 4-hydroxybenzaldehyde.

Abstract: The subject of the present invention is a process for the preparation of a 4-hydroxybenzaldehyde carrying at least one substituent in the position ortho to the OH group.It more particularly relates to the preparation of 3-methoxy-4-hydroxybenzaldehyde and of 3-ethoxy-4-hydroxybenzaldehyde.The process for the preparation of a substituted 4-hydroxybenzaldlehyde, substituted at least in the 3 position by an alkoxy group, is characterized in that it comprises subjecting a substituted phenol compound, substituted at least in the 2 position by an alkoxy group and in which the 4 and 6 positions are free, to a first stage of carboxylation in the 6 position, then to a stage of hydroxymethylation in the 4 position, followed by a stage of oxidation of the hydroxymethyl group to a formyl group, and finally to a last decarboxylation stage.

Abstract: Optically active .alpha.-(hydroxyphenoxy)-alkanecarboxylic acids or derivatives thereof, for example D-2-(4-hydroxyphenoxy)propionic acid or lower alkyl ester thereof, are prepared by (a) saponifying an alkyl ester of an optically active .alpha.-halogeno-alkanecarboxylic acid, in an alcoholic solvent medium, by reacting same with an aqueous solution of an alkali metal hydroxide, thereby providing a solution of an alkali metal salt of an optically active .alpha.-halogeno-alkanecarboxylic acid, (b) next reacting the step (a) solution thus provided with a dihydroxybenzene or salt thereof, in the presence of an alkali metal hydroxide and in an alcoholic solvent medium, and thence (c) recovering the optically active .alpha.-(hydroxyphenoxy)-alkanecarboxylic acid or derivative thereof from the medium of reaction.

Abstract: A process of preparing optically active alpha-chlorocarboxylic esters having the formula: ##STR1## from an optically active alpha-hydroxy carboxylic ester having the formula: ##STR2## in which process, an alpha-hydroxy carboxylate of formula II is brought into contact with phosgene and a compound chosen from amides, lactams and ureas, wherein R.sub.1 is an optionally substituted hydrocarbyl residue and R is preferably a methyl group.

Abstract: p-Nitrophenolic compounds, e.g., p-nitrophenol itself, are selectively prepared by (a) reacting a phenolic compound with a nitrosating agent in the presence of sulfuric acid, the concentration of which H.sub.2 SO.sub.4 being at least 60%, (b) oxidizing the p-nitrosophenolic compound thus formed with nitric acid, the concentration of sulfuric acid in the medium of reaction, upon completion of oxidation, being no greater than 80%, and (c) separating the p-nitrophenolic compound which thus precipitates.

Abstract: A process for the preparation of a brominated compound which comprises the step of reacting at least one compound selected from the group consisting of a chloroformate, a chlorosulfite and a chlorophosphite with a brominating agent for a time sufficient to obtain at least one brominated compound. In particular, an alcohol is converted into a chloroformate, chlorosulfite or a chlorophosphite, which is then brominated to obtain the desired product. In another embodiment, a brominating agent is reacted with a reactant selected from the group consisting of thionyl chloride, phosgene and phosphorous oxychloride, followed by contacting the reaction product obtained with an alcohol to be brominated.

Abstract: A process for the preparation of a brominated compound which comprises the step of reacting at least one compound selected from the group consisting of a chloroformate, a chlorosulfite and a chlorophosphite with a brominating agent for a time sufficient to obtain at least one brominated compound. In particular, an alcohol is converted into a chloroformate, chlorosulfite or a chlorophosphite, which is then brominated to obtain the desired product. In another embodiment, a brominating agent is reacted with a reactant selected from the group consisting of thionyl chloride, phosgene and phosphorous oxychloride, followed by contacting the reaction product obtained with an alcohol to be brominated.

Abstract: A process for the preparation of optically active esters of 2-chloropropionic acid of the formula: ##STR1## from an optically active lactate of the formula: ##STR2## with inversion of configuration. COOR.sub.1 in formula I and formula II is a hydrolyzable group. The lactate of formula II is brought into contact with SOCl.sub.2, followed by decomposition of the chlorosulfite formed, the process being one in which at least the decomposition stage is carried out in the presence of an ether.