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:
Dec. 02, 2025
Filed:
Oct. 07, 2021
Evonik Operations Gmbh, Essen, DE;
Evonik Operations GmbH, Essen, DE;
Abstract
A method for preparing 1,2-propanediol involves continuously reacting propene with hydrogen peroxide in the presence of a catalyst mixture, containing a quaternary ammonium salt and a polytungstophosphate, in a liquid reaction mixture containing an aqueous phase with a maximum apparent pH of 6 and an organic phase containing an alkylaromatic hydrocarbon solvent. The method then involves withdrawing the liquid reaction mixture from the reaction and adding a water-soluble sulfate salt or sulfuric acid to provide a mixture containing from 500 to 10,000 mg/kg of sulfate ions in the aqueous phase. The method further involves separating the mixture obtained into an aqueous phase (P) containing 1,2-propanediol and an organic phase (P), recycling at least a part of the organic phase (P) to the reaction, and recovering 1,2-propanediol from the aqueous phase (P). The method allows for extended operation of the reaction with little loss of tungsten and phase transfer catalyst.