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:
May. 11, 1976
Filed:
Apr. 22, 1974
Matsuyama Petrochemicals Inc., Osaka, JA;
Abstract
A method for recovering a heavy metal oxidation catalyst used in a liquid-phase oxidation process for producing terephthalic acid from the residue of the reaction mother liquor by stirring the residue together with water in the presence of molecular oxygen and a sulfur compound, subjecting the extracted mixture to a solid-liquid separation to separate the solid impurities, adding the aqueous solution containing the oxidation catalyst to an alkali metal or ammonium carbonate or an aqueous solution of an alkali metal or ammonium carbonate while maintaining the temperature of the system at about 26.degree.C to 70.degree.C, and recovering the heavy metal catalyst as a carbonate precipitate having high purity and good filterability and washability.