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A New Strategy for the Preparation of Terephthalic Acid by the Aerobic Oxidation of p ‐Xylene using N ‐Hydroxyphthalimide as a Catalyst
Author(s) -
Tashiro Yasutaka,
Iwahama Takahiro,
Sakaguchi Satoshi,
Ishii Yasutaka
Publication year - 2001
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/1615-4169(20010226)343:2<220::aid-adsc220>3.0.co;2-n
Subject(s) - terephthalic acid , chemistry , catalysis , yield (engineering) , acetic acid , nuclear chemistry , catalytic oxidation , medicinal chemistry , organic chemistry , polyester , metallurgy , materials science
A new methodology for the production of terephthalic acid ( 3 ) by the aerobic oxidation of p ‐xylene ( 1 ) using a combined catalytic system of N ‐hydroxyphthalimide (NHPI)/Co(OAc) 2 /Mn(OAc) 2 was developed. The oxidation of 1 under a dioxygen atmosphere in the presence of a catalytic amount of NHPI/NHPI(OAc) 2 /Mn(OAc) 2 at 100 °C for 14 h afforded terephthalic acid in 82% yield. Removal of Mn(OAc) 2 from the catalytic system resulted in considerable reduction in the yield of 3 . When the oxidation of 1 was carried out under a pressure of air (30 atm) at 150 °C, the reaction was completed within 3 h to give 3 in 84% yield. The oxidation of p ‐toluic acid ( 2 ), which can be prepared by the oxidation of 1 using the NHPI/NHPI(OAc) 2 system at room temperature, by the NHPI/NHPI(OAc) 2 /Mn(OAc) 2 system under pressure of air (30 atm) at 150 °C gave 3 in 95% yield. N ‐Acetoxyphthalimide (NAPI) was found to require a lower catalyst loading than NHPI, but oxidation with NAPI was slower. Thus, the oxidation of 1 catalyzed by NAPI (5 mol %)/Co(OAc) 2 (0.5 mol %)/Mn(OAc) 2 (0.5 mol %) under a dioxygen atmosphere (1 atm) in acetic acid at 100 °C gave 3 in 80% yield.