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:
Nov. 04, 2003
Filed:
Apr. 26, 2002
Krishna Kulai Rao, Kingwood, TX (US);
Russell D. Sellen, Beaumont, TX (US);
Xiaobing Feng, League City, TX (US);
James Spanswick, Wheaton, IL (US);
William F. Huber, Jr., Naperville, IL (US);
Exxon Mobil Chemical Patents Inc., Houston, TX (US);
Abstract
This invention provides a process for purifying the crude aromatic dicarboxylic acids produced by oxidation of dialkyl aromatic hydrocarbons and for using the purified acids in the preparation of polyethylene terephthalate, polyethylene naphthalate and other polyesters. The invention simplifies the manufacturing process by converting the crude aromatic acids into bis-glycol esters in an esterification reactor from which the esterified partial oxidation impurities present in the oxidation product are removed by distillation in distillation tower After removal of the volatile impurities, the dicarboxylic acid esters can separated by distillation in distillation tower or by crystallization and converted to polyesters by polycondensation. The volatile impurities removed as overhead from tower can be recycled as stream to the oxidation reactor where they act as oxidation promoters thereby optionally allowing for a bromine-free oxidation process for dialkyl aromatic hydrocarbons.