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:
Apr. 10, 2001
Filed:
Sep. 05, 2000
Gary Woodward, Worcester, GB;
Timothy Kevin Brierley, Cheshire, GB;
Ranbir Singh Padda, Oxon, GB;
John Christopher Harris, Worcester, GB;
Aidan Michael Hayes, Worcestershire, GB;
Rhodia Consumer Specialties Limited, West Midlands, GB;
Abstract
A method for the preparation of alkene phosphonic acids and salts thereof, such as VDPA (vinylidene diphosphonic acid) is disclosed. The products can be produced in a stable, substantially pure form and in high yield. The method includes the azeotropic removal of water from salts of &agr;-hydroxy-alkane diphosphonic acid dimer or corresponding acids thereof, and the pyrolysis of the dehydrated reactant at a temperature of from 170° C. to 300° C. There may be included a step to convert anhydrides which have been formed during the pyrolysis. The method may include the use of heat transfer agents and/or bases, and may be carried out at elevated or reduced pressure.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile