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:
Jun. 16, 1987
Filed:
Nov. 21, 1984
Klaus-Dieter Steffen, Hennef, DE;
Gunther Meyer, Troisdorf, DE;
Dynamit Nobel AG, Troisdorf, DE;
Abstract
A method for the preparation of 3,4-dihydro-alpha-pyrones by the thermolysis of 5-hydroxymethyl-gamma-butyrolactone in a liquid medium at temperatures between 300.degree. and 400.degree. C. and in the presence of aluminosilicates as catalysts is disclosed. The dihydropyrone that forms is distilled out of the reaction medium together with the reaction water immediately after its formation. Heat transfer oils, including, for example, polynuclear aromatic compounds joined together by methylene bridges or other bridge groupings, are especially suitable as heat transfer oils. The method has the advantage of permitting the temperature to be regulated within a definable range so that secondary reactions due to local overheating or imprecise temperature control occur to only a limited degree if at all.