Solvay Interox Gmbh

Peroxid-chemie Gmbh

Solvay Interox (societe Anonyme)

Richard Roesler

Werner Doetsch

Alun P James

Graham R Horne

Manfred Mathes

Werner Zeiss

Romano Pardini

Soraya Parvaneh

Pier-Luigi Deli

Rudolf Siegel

Lido Signorini

Gerd Hecken

Robert Owen

Stefano Bigini

Uwe Droste

Michael Gnann

Siegfried Schelle

Alfred Soentgerath

Hans-Ludwig Pfeifer

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. In some embodiments at least a fraction of the mother liquor introduced into the dissolution tank is obtained by extraction from the reaction vessel and in other embodiments a fraction of the sodium percarbonate is introduced in solution in the mother liquor and a fraction is introduced in particulate form directly into the reaction vessel. Large particle sodium percarbonate is provided which has a 7 day aged heat emission at 40C. of not more than 3 &mgr;W/g measured in a microcalorimeter over 16 hours that is lower than the heat emission from conventionally produced sodium percarbonate employing a chloride salting-out agent.

Sodium percarbonate and process for producing sodium percarbonate

Sodium percarbonate exhibits a tendency to decompose in built compositions and particularly detergent compositions built with zeolites. The tendency can be ameliorated by selecting sodium percarbonate which intrinsically has a mean particle size of from 500 to 1000 microns and not more than 20% by weight of below 350 microns and has a moisture pick-up when measured in a test at 80% relative humidity and 32&deg; C. after 24 hours of not greater than 30 g/1000 g sample. A suitable sodium percarbonate can be made most conveniently by crystallisation from a bulk saturated solution of sodium percarbonate in a crystalliser/classifier that does not employ a conventional chloride salting-out agent.

Compositions containing sodium percarbonate

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 35&deg; C. 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. In some embodiments at least a fraction of the mother liquor introduced into the dissolution tank (,) is obtained by extraction from the reaction vessel (,) and in other embodiments a fraction of the sodium percarbonate (,) is introduced in solution in the mother liquor (,) and a fraction is introduced in particulate form (,) directly into the reaction vessel (,). Large particle sodium percarbonate is provided which has a 7 day aged heat emission at 40&deg; C. of not more than 3 &mgr;W/g measured in a microcalorimeter over 16 hours that is lower than the heat emission from conventionally produced sodium percarbonate employing a chloride salting-out agent.

Process for producing sodium percarbonate

Solid peroxo compounds and peroxy compounds stabilized by coating

Stable, solid acetyl peroxyborate compounds which are active oxygen-containing compounds derived from acetic acid and boron-oxygen compounds. The compounds of the invention have a peracetic acid content which can be liberated instantly and directly in water with only minor formation of hydrogen peroxide The acetyl peroxyborates of the invention are useful in washing, bleaching and cleaning agent and disinfectant applications and as oxidizing agents in organic synthesis.

Stable solid acetylperoxyborate compounds

A process is described for preparing peroxyborate agglomerates having an active oxygen content of at least 14% by weight in which amorphous primary particles composed of peroxyborate prepared by a spray drying process are subjected to compacting pressing-agglomeration. Briquettes, compressed strips and tablets can be obtained which can be comminuted, if desired, to peroxyborate granules of desired particle size and bulk density. Advantageous, optionally colored, peroxyborate agglomerates, particularly peroxyborate granules are prepared. Preferred agglomerates and granules are composed of sodium peroxyborates.

Process for preparing peroxyborate agglomerates

Sodium percarbonate particles stabilized by being coated with a solid coating material which contains a mixture of sodium carbonate and sodium chloride, optionally together with one or more auxiliary agents used in the manufacture of sodium percarbonate.

Sodium percarbonate stabilized by coating

A process for preparing microcrystalline perborate hydrate products and highly concentrated, storage stable aqueous solutions used for this purpose which have a stable active oxygen content and a boron content of 3 to 8% by wt. based on the total weight of the solution. The products of the invention are suitable for numerous uses in the field of bleaching agent, disinfectant and liquid detergent formulations, and other fields of use.

Process for preparing microcrystalline perborate products

A process for producing sodium perborate monohydrate agglomerates or granules in which primary particles of sodium perborate monohydrate produced from sodium perborate tetrahydrate by a dehydration process are subjected to compacting pressing agglomeration, and the resulting agglomerates are subsequently comminuted to granules.

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Kraainem, Belgium

Richard Roesler