US Patent:
20060205977, Sep 14, 2006
Inventors:
Charles Sumner - Kingsport TN, US
Robert Hembre - Johnson City TN, US
David Lange - Irmo SC, US
Gino Lavoie - Kingsport TN, US
Brent Tennant - Kingsport TN, US
Thomas Floyd - Kingsport TN, US
Bryan Davenport - Columbia SC, US
Daniel Compton - Kingsport TN, US
Joseph Bays - Kingsport TN, US
International Classification:
C07C 51/16
C07C 51/255
Abstract:
Processes for producing terephthalic acid are disclosed, the processes comprising combining in a reaction medium p-xylene, a solvent comprising water and one or more saturated organic acids having from 2-4 carbon atoms, and an oxygen-containing gas, at a temperature from about 135 C. to about 165 C., in the presence of a catalyst composition comprising cobalt atoms and manganese atoms, with bromine atoms provided as a promoter. The amount of cobalt used may be from about 1,800 ppm to about 6,000 ppm, with respect to the total weight of the liquid in the reaction medium, and the weight ratio of cobalt to manganese may be from about 40 to about 400. The processes according to the invention produce terephthalic acid as a precipitated reaction product, with typically no more than about 10 ppm 2,6-dicarboxyfluorenone produced, with respect to the weight of the terephthalic acid produced, or no more than about 20 ppm 2,6-dicarboxyfluorenone, with respect to the total weight of the reaction medium, per batch or upon one pass through a reactor. The terephthalic acid so produced may be further purified by one or more additional oxidation reactions, without the need for expensive hydrogenation purification processes.