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. 17, 2009
Filed:
Apr. 08, 2003
Raymond Vincent Heavon Jones, Grangemouth, GB;
Alan John Whitton, Grangemouth, GB;
Colin John Bennie, Grangemouth, GB;
David John Ritchie, Grangemouth, GB;
Pascal Bugnon, Monthey, CH;
Raymond Vincent Heavon Jones, Grangemouth, GB;
Alan John Whitton, Grangemouth, GB;
Colin John Bennie, Grangemouth, GB;
David John Ritchie, Grangemouth, GB;
Pascal Bugnon, Monthey, CH;
Syngenta Crop Protection, Inc., Greensboro, NC (US);
Syngenta Limited, , GB;
Abstract
3-Isochromanone is prepared by partially chlorinating o-tolylacetic acid with sulphuryl chloride or chlorine gas in an inert organic solvent in the presence of a free radical initiator. The 2-chloromethylphenylacetic acid first obtained is converted to 3-isochromanone by treatment with a base and separated from unreacted o-tolylacetic acid, which is in the form of a salt, by a phase separation technique. The separated o-tolylacetic acid salt is converted to o-tolylacetic acid by controlled acidification and the o-tolylacetic acid is extracted for re-use. The invention reduces the formation of unwanted, over-chlorinated by-products and leads to a more efficient process.