| 摘要 |
PURPOSE:To obtain terephthalic acid of high quality by liquid phase-oxidizing para-xylene, etc., by molecular O2 in acetic acid-solvent in the presence of specific catalyst and controlling generated terephthalic acid in liquid phase part in a reactor in which oxidation reaction is substantially finished to specific concentration. CONSTITUTION:Para-xylene or oxidized intermediate of para-xylene is used as raw material and oxidized in liquid phase by molecular O2 in acetic acid solvent and in the presence of catalyst containing heavy metal and bromine such as three elements system of Co-Mn-Br and concentration of generated terephthalic acid in liquid phase part in a reactor in which the oxidation reaction is substantially finished (>=95wt.%) is controlled to 36-50wt.%, then terephthalic acid of high quality, useful for raw material of polyester, is continuously obtained. Besides, said process industrially has large merits, for instance, existing amount of acetic acid solvent is reduced, quality of terephthalic acid is improved with suppressing combustion of acetic acid solvent and total amount of liquid treated in the process is reduced, thus necessary amounts of thermal energy and catalyst, etc., are also reduced. |
