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. 06, 1976
Filed:
Aug. 16, 1974
Hans Junek, Graz, OE;
Herwig Fischer-Colbrie, Graz, OE;
Lonza Ltd., Gampel, Valais, CH;
Abstract
A process for preparing a 4-hydroxyphenyl-1,3-dioxo-2-indenylidene-acetonitrile. The process includes reacting 2-dicyanomethylene-1,3-indanione with a phenol having the formula: ##SPC1## Wherein R.sub.1 and R.sub.2 are the same or different and are each hydrogen, halogen, cyano, alkyl having one to four carbon atoms or alkoxy having one to four carbon atoms, at a temperature between 150.degree. and 250.degree.C. The reaction is preferably conducted in the presence of an organic solvent. A 4-hydroxyphenyl-1,4-dioxo-2-indenylidene-acetonitrile having the formula: ##SPC2## Wherein R.sub.1 and R.sub.2 are the same or different and are each hydrogen, halogen, cyano, alkyl having 1 to 4 carbon atoms or alkoxy having 1 to 4 carbon atoms. Such compounds are useful as indicators.