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:
Feb. 27, 2001
Filed:
Mar. 23, 1999
Yinong Ma, Westfield, MA (US);
Jerald D. Heise, St. Louis, MO (US);
Monsanto Company, St. Louis, MO (US);
Abstract
A process for the manufacture of phosphorous acid by selective hydrolysis of phosphite esters. A hydrolysis feed mixture comprising phosphite esters and phosphate esters is contacted with liquid water or steam to selectively hydrolyze the phosphite esters to phosphorous acid. The feed mixture may be prepared by oxidation of elemental phosphorous in the presence of an alcohol. In the oxidation and/or a subsequent esterification step, P(III) and P(V) oxyacids produced in the oxidation reaction are esterified, preferably quantitatively. The ester mixture may be washed to remove unesterified phosphoric and hypophosphorous acid, after which the selective hydrolysis is carried out.