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:
Jan. 30, 1990
Filed:
Dec. 14, 1988
Willibald Schoenleben, Heidelberg, DE;
Basf Aktiengesellschaft, Ludwigshafen, DE;
Abstract
N,N'-dialkyl-substituted cyclic urea derivatives of the general formula I ##STR1## where R.sup.1 and R.sup.2 are each alkyl of 1 to 8 carbon atoms and A is CR.sup.3 R.sup.4 -CR.sup.5 R.sup.6 - or CR.sup.3 R.sup.4 -CR.sup.5 R.sup.6 -CR.sup.7 R.sup.8, where R.sup.3 to R.sup.8 are each hydrogen or alkyl of 1 to 17 carbon atoms, are prepared by reacting a diamine of the formula II ##STR2## with carbon dioxide, by a method in which the reaction is carried out in the gas phase in the presence of an oxide of an element of main group three or four or subgroup two to six of the Periodic Table, or a mixture of these, or in the presence of an aluminum silicate or magnesium silicate. 1,3,4-trimethyl-2-imidazolidinone is used as a polar solvent at low temperatures.