The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 19, 2002
Filed:
Feb. 28, 2001
Alun P. James, Liverpool, GB;
Graham R. Horne, Warrington, GB;
Richard Roesler, Kraainem, BE;
Lido Signorini, Brussels, BE;
Robert Owen, Brussels, BE;
Soraya Parvaneh, Livorno, IT;
Romano Pardini, I-Rosignano-Solvay, IT;
Stefano Bigini, I-Terni, IT;
Manfred Mathes, Bad Hoenningen, DE;
Uwe Droste, Bad Hoenningen, DE;
Pier-Luigi Deli, Ne/Genova, IT;
Solvay Interox (Societe Anonyme), Brussels, BE;
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. 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.