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. 28, 1977
Filed:
Sep. 02, 1975
Jon J Harper, Naperville, IL (US);
Antonio E Navarrete, Downers Grove, IL (US);
Richard J Thomas, Huntington Beach, CA (US);
Standard Oil Company, Chicago, IL (US);
Abstract
A process is disclosed for producing the dimethyl esters of aromatic dicarboxylic acids wherein the acid is esterified with a low molecular weight alcohol, the product is crystallized and separated to isolate a mass of the diester crystals and recover a mother liquor. An improvement in such process resides in the thermal oxidation with molecular oxygen of a mother liquor material to produce a mono methylphthalate from either p-methyl toluate or methyl-4-carboxybenzaldehyde. A portion of the oxidized mother liquor is recycled to the esterification zone wherein the mono methylphthalate can be esterified to the dimethyl ester while another portion of the oxidized mother liquor stream is passed to an evaporation treatment zone, preferably a wiped film evaporator, wherein overhead material is separated from a high boiling bottoms material and recycled to the esterification reaction zone. The high boiling bottoms stream from the evaporation treatment zone is purged from the system thereby removing from the overall process high boiling organics including ash.