Abstract: Sodium percarbonate is traditionally made in a crystallization process from aqueous hydrogen peroxide and sodium carbonate with recycle of mother liquor in the presence of a substantial concentration of a salting out agent, conventionally sodium chloride. The invention provides a process intended to be conducted without addition of chloride salting-out agent in which the dissolution step is controlled to restrict the sodium carbonate concentration to below 95%, preferably 60 to 90% of its saturated concentration at a temperature preferably controlled to at most 35C. and the mole ratio of hydrogen peroxide:sodium carbonate in the reaction vessel is controlled to between 0.7 to 1.2:1, and preferably about 1:1.

Abstract: The present invention relates to an apparatus for the continuous manufacture of solid particles of alkali metal persalts by reaction of an aqueous hydrogen peroxide solution with an aqueous solution of an alkali metal salt and crystallization of the persalt. The persalt is formed in a crystallizer classifier, which is made up of stirred region and a growth region for the persalt crystals a non-stirred clarifying region for the solution and a classification region for the particles obtained by elutriation in a liquid stream withdrawn in the clarifying region.

Abstract: Process for bleaching a chemical paper pulp to a brightness of at least 89° ISO, consisting in subjecting the pulp to a treatment sequence of several stages including a final bleaching stage with hydrogen peroxide in alkaline medium carried out in the presence of at least one stabilising agent and at a consistency of at least 25% by weight of solids, the stages preceding this final stage having purified the pulp so that its manganese content does not exceed 3 ppm by weight with respect to the solids and that the pulp has been delignified beforehand to a kappa number not exceeding 5.

Abstract: Continuous process for the manufacture of solid particles of alkali metal persalts by reaction of an aqueous hydrogen peroxide solution with an aqueous solution of an alkali metal salt and crystallization of the persalt formed in a crystallizer-classifier comprising a stirred formation and growth region for the persalt crystals, a nonstirred clarifying region for the solution and a classification region for the particles obtained by elutriation in a liquid stream withdrawn in the clarifying region.Plant for manufacturing the said particles.

Abstract: A process is proposed for the chemical oxidative treatment of a medium, e.g. sewage sludge, containing organic constituents, which comprises two process steps. In the first process step, the medium is heated to a first preset low temperature range and kept in this temperature range for a preset treatment duration. In a second process step, the sludge is then heated to a second preset low temperature range, pressurized in a preset low pressure range and kept in this temperature and pressure range for a preset treatment duration. In the course of this, an oxygen-containing gas, e.g. air or oxygen-enriched air or technical grade oxygen is introduced into the medium at least intermittently. The low temperatures and pressures provided in the two process steps are below or at most in the lower third of the temperature and pressure ranges of 150.degree.-370.degree. C. and 10-220 bar conventional in the wet-oxidation processes.

Abstract: Aqueous solution of hydrogen peroxide stabilized by incorporation of a composition containing a mixture of an alkali metal pyrophosphate or alkaline earth metal pyrophosphate with a stabilizer belonging to the category of aminopolycarboxylic acids corresponding to the following general formula: ##STR1## where x is an integer equal to 0, 1 or 2 andy is also an integer equal to 0, 1 or 2;and salts of these acids.The solution finds application for bleaching textiles and paper pulps.

Abstract: A process for bleaching a chemical paper pulp, including, in the order recited, subjecting the chemical paper pulp to treatment with oxygen in a preliminary delignification stage which does not employ chlorine in an acidic medium or a combination of chlorine and chlorine dioxide in an acidic medium; subjecting the chemical paper pulp to treatment with peroxymonosulphuric acid in a peroxymonosulphuric acid stage carried out at a temperature ranging between 75.degree. and 100.degree. C. for a period ranging between 70 and 150 minutes and at a pulp consistency of ranging between 12 and 25% of dry matter; and subjecting the chemical paper pulp to treatment with alkaline hydrogen peroxide in an alkaline hydrogen peroxide stage.

Abstract: Continuous process for the manufacture of solid alkali metal persalt particles coated by crystallization of a supersaturated aqueous solution of persalts and covering of the persalt particles in a post-crystallization vessel into which at least one coating agent is introduced and in which crystallization of the coating agent around the persalt particles is carried out under controlled temperature and stirring conditions.

Abstract: Process for bleaching a chemical paper pulp by means of a sequence of treatment stages involving at least one stage with an enzyme and at least one stage with a peroxyacid.

Abstract: Process for improving the selectivity of the delignification of a chemical paper pulp by employing a peroxyacid, in which the unbleached pulp originating from the cooking operation is treated with an aqueous solution of this organic peroxyacid in the presence of at least one stabilizer selected from phosphonic acids and their salts.

Abstract: Process for the synthesis of alkylated aromatic hydrocarbons containing a saturated alkyl chain comprising at least four carbon atoms, according to which an aromatic hydrocarbon substituted by a saturated short-chain alkyl group comprising one to three carbon atoms is reacted with an olefin in the presence of a catalyst which comprises at least one alkali metal or one alkali metal hydride impregnated on an alumina support and the catalyst is prepared in the reaction medium in the presence of the aromatic hydrocarbon containing a short alkyl chain by mixing anhydrous alumina with the alkali metal hydride or with the alkali metal, the ratio by weight of the alkali metal or of the alkali metal hydride to the alumina support being between 0.6 and 1.8. Use of the process for the synthesis of tert-amylbenzene by alkylation of cumene with ethylene.

Abstract: Organophosphonic polymers of general formula (I) where Y is a methyl or ethyl group or hydrogen and Z is hydrogen, the ammonium group, an alcaline metal or an alcaline earth metal. A method for producing these polymers comprises three stages: production of a monomer by reacting a ketene with diethylphosphite in the presence of an acid catalyst; polymerization of the monomer in solution in a solvent by means of a free radical initiator; hydrolysis of the polymer obtained by means of a concentrated solution of inorganic or inorganic based acid. Aqueous solution of hydrogen peroxyde stabilized by means of said polymers.

Abstract: Process for the synthesis of aromatic alkylated hydrocarbons with a saturated alkyl chain including at least four carbon atoms, according to which an aromatic hydrocarbon, replaced by an alkyl group with a short saturated chain comprising one to three carbon atoms, is made to react with an olefin in the presence of a catalyst made up of at least one alkaline metal or a alkaline metal hydride impregnated on an alumina support. The process is characterised by the fact that the catalyst is prepared in the reaction medium in the presence of the aromatic hydrocarbon with a short alkyl chain by mixing anhydrous alumina with the alkaline metal hydride or with the alkaline metal, and then the olefin is introduced in order to start the reaction.

Abstract: Epoxides are manufactured by reacting olefines, such as cyclohexene, isoamylene, alpha-pinene, allyl alcohol, 2,5-dihydrofuran and styrene, with hydrogen peroxide, in a homogeneous liquid reaction mixture containing less than 10% by weight of water, in the presence of a compound of a metal of group 6a, such as selenium dioxide or selenous acid, and of an organic nitrogen-containing base having a pKa of not more than 8, such as pyridine, chloropyridine, collidine, quinoline, isoquinoline or a lutidine.

Abstract: Aromatic tertiary amines are oxidized by means of hydrogen peroxide in an inert solvent medium in the presence of a catalyst selected from metal selenium and compounds of selenium.The process is applied to the preparation of oxides of heterocyclic aromatic tertiary amines and oxides of non-heterocyclic tertiary amines, in which the nitrogen atom is substituted by at least 1 aromatic nucleus.

Abstract: The seeds are coated with a polyester with a low melting point and a peroxy compound.The process involves treating the seeds with a peroxy compound in the presence of a solution of the polyester in an organic solvent or with the polyester in the liquid or melted state.

Abstract: A process for the manufacture of an explosive cartridge in a tubular casing, including mixing a solution containing hydrogen peroxide, an oxidizable organic material, and at least one precursor monomer of a gelling agent; and reacting the at least one precursor monomer to form macromolecules of the gelling agent in situ in the tubular casing.

Abstract: Process for the manufacture of hydrogen peroxide by photoreduction of molecular oxygen in an aqueous medium in the presence of visible light, of semicarbazide acting as an electron donor and of a photosensitizer selected from among Bengal Rose and the rutheniumII tris(2,2'-dipyridyl) complex, the pH of the reaction medium being kept at a value above 9.

Abstract: A quinoxaline is oxidized by means of hydrogen peroxide in an inert solvent medium in the presence of water and of a catalyst selected from selenium and selenium compounds.The process applies to the preparation of substituted and unsubstituted 2,3-dihydroxyquinoxalines.

Abstract: Particles of peroxygen compounds chosen from alkali metal persalts, which particles are stabilized by incorporation of a combination of metal ions including magnesium ions and zinc ions.