Produits Chimiques Ugine Kuhlmann

Louis Mesaros

Paul Mollard

Improved processes for preparing sodium percarbonate, 2Na.sub.2 CO.sub.3.3H.sub.2 O.sub.2, which can have an apparent density of 0.6 to 1 g/cm.sup.3 and a mean particle diameter of 210 to 610 microns, which processes comprise treating a sodium carbonate monohydrate or hydrate having 75 to 90% of Na.sub.2 CO.sub.3 and having a density equal to or even greater than 1.2 g/cm.sup.3 with 60 to 80% aqueous hydrogen peroxide, the reaction mixture containing a small quantity of nonionic surfactant stable in hydrogen peroxide and alkaline solutions, the percarbonate formed being well adapted for use in detergent compositions.

Processes for preparing sodium percarbonate

Processes for the preparation of mixed persalts capable of liberating hydrogen peroxide in aqueous solutions and stable in dry detergent compositions, which processes comprise adding 60-80% H.sub.2 O.sub.2 containing 0.6-1.8% EDTA to sodium carbonate monohydrate or to a sodium carbonate hydrate containing from 75-90% sodium carbonate, wherein sodium or potassium sulfate, sodium or potassium pyrophosphate, sodium metasilicate, sodium disilicate, sodium citrate, sodium glucoheptonate, sodium perborate, anhydrous sodium carbonate, potassium carbonate, or mixed sodium and potassium carbonate or a mixture thereof is added to the reaction mixture, together with the products produced and use thereof as oxidizing agents in detergent mixtures.

Mixed persalts stable in detergent compositions

Sodium Chlorite is made stable under storage conditions by (1) admixing with the sodium chlorite a stabilizing salt chemically inert to sodium chlorite and having at least one hydrate whose melting point is higher than about 50.degree. C, in amount such that said stabilizing salt can capture a quantity of water equal to at least about 5% of the weight of the sodium chlorite (NaClO.sub.2), the weight of the water in the total mixture being at least about 5% of the weight of said sodium chlorite and (2) drying the mixture sufficiently to reduce the water not captured by the stabilizing salt to an amount equal approximately to zero. Sodium chlorite thus stabilized is thermally stable and does not congeal into a solid mass even when stored in drums for several months at 50.degree. C.

Storage-stable sodium chlorite

Processes for the preparation of sodium percarbonate having substantially the formula 2Na.sub.2 CO.sub.3.3H.sub.2 O.sub.2, the processes being particularly suited to the use of ordinary sodium carbonate, which processes comprise reacting 60 to 80 percent hydrogen peroxide with sodium carbonate monohydrate or a hydrate of sodium carbonate containing from about 75 to 90 percent sodium carbonate; and products obtained thereby, particularly those percarbonate products having an excellent resistance to shock and attrition and effective densities of 0.61-0.92 g/cm.sup.3 and mean particle diameters of 250-610 microns.

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Oullins, France

Louis Mesaros