An
efficient elevated-pressure catalytic oxidative process (2.5
mol % Co(NO
3
)
2
, 2.5 mol % MnBr
2
,
air (30 bar), 125 °C, acetic acid, 6 h) has been developed to
oxidize
p
-cymene into crystalline white terephthalic
acid (TA) in ∼70% yield. Use of this mixed Co
2+
/Mn
2+
catalytic system is key to obtaining high 70% yields of
TA at relatively low reaction temperatures (125 °C) in short
reaction times (6 h), which is likely to be due to the synergistic
action of bromine and nitrate radicals in the oxidative process. Recycling
studies have demonstrated that the mixed metal catalysts present in
recovered mother liquors could be recycled three times in successive
p
-cymene oxidation reactions with no loss in catalytic activity
or TA yield. Partial oxidation of
p
-cymene to give
p
-methylacetophenone (
p
-MA) in 55–60%
yield can be achieved using a mixed CoBr
2
/Mn(OAc)
2
catalytic system under 1 atm air for 24 h, while use of Co(NO
3
)
2
/MnBr
2
under 1 atm O
2
for
24 h gave
p
-toluic acid in 55–60% yield. Therefore,
access to these simple catalytic aerobic conditions enables multiple
biorenewable bulk terpene feedstocks (e.g., crude sulfate turpentine,
turpentine, cineole, and limonene) to be converted into synthetically
useful bio-
p
-MA, bio-
p
-toluic acid,
and bio-TA (and hence bio-polyethylene terephthalate) as part of a
terpene based biorefinery.