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:
Mar. 13, 1990
Filed:
Jul. 22, 1988
Helmut Blum, Duesseldorf, DE;
Siglinde Hemmann, Meerbusch, DE;
Henkel Kommanditgesellschaft auf Aktien, Duesseldorf, DE;
Abstract
Hydroxyacetonitrile diphosphonic acid corresponding to the following general formula ##STR1## in which M represents H or a cation of a base, and salts thereof; to a process for their preparation comprising reacting 3-R.sup.1 -3-oxo-1-aminopropane-1,1-diphosphonic acids corresponding to the following general formula ##STR2## in which R.sup.1 is a tertiary substituted alkyl group, an optionally substituted cycloalkyl group or an optionally substituted aryl or heteroaryl radical, with nitrous acid, the secondary product R.sup.1 -COOH and unreacted starting material are separated off from the reaction mixture and the hydroxyacetonitrile diphosphonic acid is obtained in the form of a salt by addition of a base; and to the use of the above compounds as complexing agents and as thresholders.