2.1 Cumene oxidation
CNTs used in the oxidation reaction of cumene were obtained from
Zhongshan CNM Plastic Co., Ltd., and the metal impurities in CNTs were
tested by ICP-AAS. ZnCl2, ZnBr2 and
ZnAc2 were used as additive, which were purchased from
Aladdin.
The cumene oxidation reaction was carried out in a three-neck flask (25
mL), supplied with a magnetic stirrer, reflux condenser and the oil
bath. Firstly, CNTs (100 mg), additive (10 mg), and cumene (10 mL) were
added into the flask, sonicated for 5 min, then heated to preconcerted
temperature (80 ℃) followed by the bubbling of 25
mL·min-1 oxygen for 8 h. When the reaction was over,
the reaction mixture was cooled to room temperature and filtered to
separate the liquid for detection.
The
concentration of CHP was determined according to the iodometric
method.[20] After the reduction of CHP to PP via
triphenylphosphine reaction, the other liquid products were detected by
gas chromatography (an Agilent GC-7890B) equipped with a DB-1701
capillary column (30 m × 0.25 mm ×
0.25 μm) and a flame ionization detector.