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. 02, 1987
Filed:
Feb. 03, 1986
Michael Saska, Baton Rouge, LA (US);
Louisiana State University and Agricultural and Mechanical College, Baton Rouge, LA (US);
Abstract
This invention relates to a process for the purification of crude terephtic acid. The process includes heating the crude acid on a first plate and locating a second plate adjacent the first plate whereby vapors emanating from the crude acid form a sublimate on the second plate. The principal impurity removed is 4-carboxybenzaldehyde. The crude acid produced is applied to the first plate as a layer having a thickness of about 2 to about 5 mms thick and heated to a temperature of from about 180.degree. to about 220.degree. C. The upper plate is not heated except by the convective heat transfer and the heat of sublimation provided by the vapor moving from the crude acid layer to the second plate.