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:
Oct. 23, 2001
Filed:
Dec. 28, 1999
Alexa B. Sommer, Pittsburgh, PA (US);
Mary Ann Wittig, Carnegie, PA (US);
Edwin Ray Hortelano, Charleston, SC (US);
Philip E. Yeske, Cologne, DE;
Jane F. Ciebien, Charleston, SC (US);
Bayer Corporation, Pittsburgh, PA (US);
Abstract
A method for making an aliphatic diisocyanate by (a) phosgenating an aliphatic diamine in the presence of an inert solvent or gas to form a crude reaction mixture; (b) distilling the crude reaction mixture to form an aliphatic diisocyanate production stream and an aliphatic diisocyanate waste stream; (c) introducing the aliphatic diisocyanate waste stream to a chamber and placing the waste stream under supercritical fluid conditions sufficient to dissolve an appreciable amount of the aliphatic diisocyanate component in the supercritical fluid; (d) separating the dissolved aliphatic diisocyanate component from the waste stream, wherein the remaining waste stream is a supercritically-purged aliphatic diisocyanate waste stream; (e) lowering the pressure sufficiently to precipitate the aliphatic diisocyanate component.