Abstract: The invention relates to a process for the preparation of hydroxybenzaldehydes by oxidation of hydroxybenzylic alcohols through oxygen or oxygen-containing gas, said process being carried out in aqueous alkaline medium in the absence of any catalyst whatsoever, at a temperature comprised between 25.degree. and 50.degree. C. and in the presence of an alkaline hydroxide in such a quantity that the molar ratio of alkaline hydroxide to hydroxybenzylic alcohol used is comprised between 2.25 and 10.

Abstract: Strong cationic polyelectrolytes in powder form based on acrylamide and quaternized or salified dimethylaminoethyl acrylate; and the use thereof for flocculation of solid material suspensions and coalescence of emulsions.Such polyelectrolytes contain in molar proportions more than 50% of cationic units uniformly distributed along the copolymer chains. They are used for flocculating colloidal suspensions and/or coalescing emulsions, especially, in sewage water purification installations.

Abstract: The invention relates to obtaining aromatic nitriles of general formula: (R).sub.n --C.sub.6 H.sub.4 --CN, where n=1, 2 or 3, and the rest R, identical or different represent an atom of hydrogen, chlorine or bromine or an alkyl, aryl, alkoxy, alkylamino, hydroxy or amino group, by a process comprising decarboxylating ammoxidation reaction, in an alkaline aqueous medium, at a pH higher than, or equal to, 13, in the presence of a catalyst based on one or several transition metals and an alkaline hydroxide, applied to an arylglyoxylic acid free or salified, of the formula: (R).sub.n --C.sub.6 H.sub.4 --CO--COOH (where n and R have the above-mentioned meanings), or to one of its functional derivatives of the lactone, lactame or C.sub.1 -C.sub.3 -alkyl ester type.

Abstract: The invention relates to a process for preparation of hydroxyarylglyoxylic acids starting from hydroxyarylglycolic acids, by catalytic oxidation in an aqueous alkaline medium to pH higher than, or equal to, 11.5, through oxygen or oxygen-containing gas, characterized in that it is carried out in homogeneous phase at a temperature lower than, or equal to, 30.degree. C., and in the presence of cupric ions, and in that at the end of the reaction, the desired acid is isolated from the reactional medium through acidification to pH of about 0.5.The sodium parahydroxyphenylglyoxylate is obtained when acidification is stopped at pH=5, at the end of the reaction.

Abstract: Sodium paraformylphenolate crystallized with two molecules of water is manufactured by:(a) condensing glyoxylic acid with an excess of phenol in water in the presence of sodium hydroxide at a temperature comprised between 30.degree. C. and 100.degree. C.;(b) neutralizing the solution thus obtained and then freeing it from the unconverted phenol by steam distillation or extraction with a water-immiscible organic solvent and then subjecting it hot under a pressure of oxygen, to a catalytic decarboxylating oxidizing degradation in the presence of sodium hydroxide;(c) allowing the aqueous solution so-obtained, after removal of the catalyst by filtration, and then concentration hot under vacuum to 60% plus or minus 10% of its initial volume, to crystallize; and(d) draining the precipitated crystals, washing them and then drying them to constant weight under vacuum of 1 mm of mercury at 20.degree. C.

Abstract: The invention relates to a process of preparation of racemic hydroxyarylglycolic acids and the novel products resulting therefrom.According to such process glyoxylic acid is condensed in water in the presence of an alkaline agent at a temperature of between 35.degree. and 100.degree. C., on an excess, or not, of phenolic aromative derivative other than phenol, having at least one proton on either of the ortho or para positions with respect to the phenol function.Application to the production of novel acids such as 4-hydroxy 3-tertiobutyl mandelic acid, 2-hydroxy 5-tertiobutyl mandelic acid, 3-chloro 4-hydroxy mandelic acid, 2-fluoro 4-hydroxy mandelic acid, monohydrated 3,5-dimethoxy 4-hydroxy mandelic acid, 2-hydroxy 5-methyl mandelic acid, (1-hydroxy 2-naphthyl) glycolic acid, 4-ethyl 2-hydroxy mandelic acid, and 4-hydroxy 3-methyl mandelic acid.

Abstract: Cationic polyelectrolytes in water-soluble powder form, applicable to the flocculation of municipal sludge comprise copolymers of acrylamide and of quaternized or salified dimethylamino-ethyl acrylate, containing in molar proportions 10 to 50% of cationic units distributed regularly along the copolymer chains. They have an intrinsic viscosity higher than 6 and a measured cationicity higher than 90% of the theoretical cationicity.

Abstract: Demethylation of the 3,4,5-trimethoxybenzoic acid is carried out in the presence of an excess of alkali hydroxide in an amount of ethylene glycol just sufficient to obtain a heterogeneous medium sufficiently fluid in the course of the operation. The ethylene glycol monomethyl ether and the water formed are distilled off progressively with their production and the resulting 4-hydroxy-3,5-dimethoxybenzoic acid is separated by acidification by means of a strong acid and crystallization.