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. 01, 1994
Filed:
Jul. 31, 1992
Kurt A Hackl, Linz, AT;
Heinz Falk, Linz, AT;
Chemie Linz Gesellschaft m.b.H., Linz, AT;
Abstract
Process for the preparation of very pure ureas of the formula phenyl--(NH--CO--NR.sub.1 R.sub.2).sub.n in which phenyl represents an unsubstituted or substituted phenyl or phenylene group and R.sub.1 and R.sub.2 are either identical and each represent an alkyl group, or are different, in which case R.sub.1 represents a hydrogen atom and R.sub.2 represents an alkyl or phenyl group, or R.sub.1 and R.sub.2, together with the nitrogen atom, represent an aliphatic heterocyclic ring and n is the number 1 or 2, by reacting a phenylurea of the formula phenyl--(NH--CO--NH.sub.2).sub.n with an amine of the formula NR.sub.1 R.sub.2 H at temperatures from 100 to 200.degree. C. in a diluent which is inert under the reaction conditions, the reaction being interrupted before by-products are formed, and the urea which is formed being removed from the starting compounds, and the unreacted starting compounds being returned to the process if appropriate.