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. 24, 2007
Filed:
Sep. 10, 2004
John Joseph Ostermaier, Orange, TX (US);
John Joseph Ostermaier, Orange, TX (US);
Invista North America S.A R.L., Wilmington, DE (US);
Abstract
The invention relates to the field of separation by distillation of 6-aminocapronitrile (ACN) and hexamethylenediamine (HMD) from a mixture comprising ACN, HMD, tetrahydroazepine (THA), adiponitrile (ADN) and low boilers (LB). Also disclosed is a method for producing a distillate stream comprising HMD; a side draw stream comprising ACN, THA and low levels of dimers of ACN and HMD; and a tails stream comprising ACN, THA and substantially higher levels of dimers of ACN and HMD than found in the side draw stream. The side draw stream is particularly suitable for use in the production of caprolactam since the low levels of dimers of ACN and HMD do not greatly affect the catalyst life in the caprolactam production process. The tails stream can be further distilled to produce a tails distillate stream comprising ACN and THA, which can be recycled back to the first distillation column, further increasing recovery of ACN from the feed stream. Process conditions of the method of the invention disfavor the production of 2-cyanocyclopentylideneimine (CPI).