Abstract: The present invention relates to an organopolysiloxane composition that can be vulcanized at room temperature into an elastomer that is crosslinked by polycondensation and that does not contain alkyltin-based catalysts and also to novel organopolysiloxane polycondensation catalysts.

Abstract: The present invention relates to an organopolysiloxane composition that can be vulcanized at room temperature into an elastomer that is crosslinked by polycondensation and that does not contain alkyltin-based catalysts and also to novel organopolysiloxane polycondensation catalysts.

Abstract: The present invention relates to an organopolysiloxane composition that can be vulcanized at room temperature into an elastomer that is crosslinked by polycondensation and that does not contain alkyltin-based catalysts and also to novel organopolysiloxane polycondensation catalysts.

Abstract: The present invention relates to an organopolysiloxane composition that can be vulcanized at room temperature into an elastomer that is crosslinked by polycondensation and that does not contain alkyltin-based catalysts and also to novel organopolysiloxane polycondensation catalysts.

Abstract: RTV-organopolysiloxane compositions are crosslinkable by polycondensation and are devoid of alkyltin-based catalysts; novel organopolysiloxane polycondensation catalysts are useful therefor.

Abstract: The present invention relates to an organopolysiloxane composition that can be vulcanized at room temperature into an elastomer that is crosslinked by polycondensation and that does not contain alkyltin-based catalysts and also to novel organopolysiloxane polycondensation catalysts.

Abstract: RTV-organopolysiloxane compositions are crosslinkable by polycondensation and are devoid of alkyltin-based catalysts; novel organopolysiloxane polycondensation catalysts are useful therefor.

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: The present invention relates to a novel process for the preparation of isovanillin.The process for the preparation of isovanillin according to the invention is characterized in that it consists in dealkylation being carried out using a strong acid, selectively in the 3-position, on a 3-alkoxy-4-methoxybenzaldehyde wherein said alkoxy group has at least two carbon atoms.

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: The present invention relates to a novel process for the preparation of isovanillin.The process for the preparation of isovanillin according to the invention is characterized in that it consists in dealkylation being carried out using a strong acid, selectively in the 3-position, on a 3-alkoxy-4-methoxybenzaldehyde wherein said alkoxy group has at least two carbon atoms.

Abstract: Branched saturated dinitrile byproducts, e.g. 2-methylglutaronitrile, 2-ethylsuccinonitrile and mixtures thereof, are converted into useful ethylenic nitriles by dehydrocyanating same, in vapor phase, in the presence of an at least partially acidified cation exchange substrate, notably a molecular sieve, clay, acid oxide or lamellar phosphate.

Abstract: Optionally substituted p-aminophenol compounds, easily converted into the N-acylated derivatives thereof, are prepared by hydrogenating the corresponding nitrobenzene, in solution in a saturated aliphatic monocarboxylic acid, notably acetic acid, in the presence of an effective amount of a protonic acid.