Method for preparing tin oxide sols and sols prepared thereby
AssigneeNyacol Products, Inc.
InventorThomas F. Swank
Life of this patent
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Abstract
Disclosed is a method for preparing aqueous negatively charged tin oxide sols having substantially uniform particle size no greater than about 50 nm and preferably from about 5 to about 20 nm, the sols being characterized as being substantially free of any other reagents which may adversely affect contemplated usage as a catalyst.
Claims20
The method for preparing aqueous negatively charged tin oxide sols having a particle size no greater than about 50 nm, which sols are substantially free of any additives, comprising the step of reacting a tin salt and a cation exchange resin in an aqueous medium to deionize the salt and thereby form tin oxide, the reaction being performed while maintaining a substantially constant alkaline pH of at least 8.0.
The method of preparing an aqueous negatively charged small particle size tin oxide sol comprising the steps of:
- (a) placing a small charge of an aqueous slurry of a weak acid cation resin in a reactor;
- (b) adding a small quantity of a water-soluble tin salt to the reactor to initiate tin oxide formation at a pH of at least 8.0;
- (c) substantially immediately after the addition of the tin salt begin slowly adding an aqueous solution of the remainder of the tin salt to be reacted along with additional weak acid cation exchange resin as needed to maintain a substantially constant pH;
- and
- (d) thereafter separating the resulting aqueous tin oxide sol from the resin.
An aqueous tin oxide sol wherein the sol is negatively charged, contains no additives which can adversely affect its use as a catalyst, and the tin oxide possesses a particle size less than 50 nm.
Dependencies are inferred from the claim text.