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:
May. 21, 1991
Filed:
Nov. 09, 1988
Donald A Bansleben, Columbia, MD (US);
Charles G Carter, Silver Spring, MD (US);
Ranjit Kumar, Columbia, MD (US);
W. R. Grace & Co.-Conn., New York, NY (US);
Abstract
A method of preparing phosphonate compositions comprising di-(phosphonomethyl) formal is disclosed which comprises (a) forming an intimate mixture of hydroxymethylphosphonic acid and formaldehyde or its condensates, said mixture having a least about 0.5 equivalents of formaldehyde per equivalent of hydroxymethylphosphonic acid; and (b) subjecting said intimate mixture to a temperature of between about 100.degree. C. and 180.degree. C. for a time sufficient to allow the components to react to form a reacted mixture comprising di-(phosphonomethyl) formal. Di-(phosphonomethyl) formal, phosphonate compositions wherein at least about 20 more % of the phosphonate groups are present as di-(phosphonomethyl) formal, and phosphonate compositions which comprise hydroxymethylphosphonic acid and di-(phosphonomethyl) formal such that the mole ratio of phosphonate groups present as di-(phosphonomethyl) formal to phosphonate groups present as hydroxymethylphosphonate is at least about 1:3, as disclosed, may be used for corrosion inhibition in aqueous systems.