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:
Aug. 27, 2019
Filed:
Jul. 06, 2017
Evonik Degussa Gmbh, Essen, DE;
Anne Rittsteiger, Olfen, DE;
Jan Caßens, Recklinghausen, DE;
Axel Hengstermann, Senden, DE;
Cord Knoop, Haltern am See, DE;
Anja Müller, Dortmund, DE;
Alexander Martin Rüfer, Recklinghausen, DE;
Evonik Degussa GmbH, Essen, DE;
Abstract
The present invention is directed to a process for fine purification of isophoronediamine from the production of isophoronediamine wherein the crude isophoronediamine I is subjected to a fine purification by means of two vacuum distillation columns, wherein I. in the first vacuum distillation column K I low-boiling by-products still present are removed, and a crude IPDA II is transferred from the bottom of K I into the vacuum distillation column K II, II. and in the second vacuum distillation column K II the isophoronediamine is obtained in pure form overhead and separated from the organic residues, wherein the first condenser is a partial condenser and the pure IPDA is removed therein, and wherein the second condenser is a total condenser and the residual portion of the vapor stream from K II is completely condensed therein and recycled as return stream into the first vacuum distillation column K I.