Published September 1970
One of the purification processes evaluated in this report is based on patents assigned to Mobil Chemical Company. This process employs sublimation in the purification scheme. This approach is markedly different from other purification methods that have been studied in previous reports. The principal reasons for undertaking this report were the appearance of a new, overall process for terephthalic acid production and two purification processes that were not previously evaluated in detail.
The new overall process evaluated in this study is based on patents assigned to Teijin. The principal distinction between this process and paraxylene oxidation process previously evaluated is that very large amounts of catalyst (usually cobalt acetate) are used and thereby the use of promoters such as bromine, or activators such as methyl ethyl ketone, is avoided. The very large quantity of catalyst in the system results in substantial differences in process flow scheme from those using small amounts of catalyst with promoters or activators ports.
The second purification process evaluated in this report is based specifically on patents issued to Teijin Limited, although several other companies have patented processes along similar lines. This process avoids purification of crude terephthalic acid. Instead, bis(2-hydroxy- ethyl) terephthalate (BHET) is produced and purified. BHET is directly polymerizable to poly(ethylene terephthalate).
Other PEP Related Reports:
