Oxidation of styrene by formic acid-H_2O_2 system

Oxidation of styrene was studied using different systems in the absence of catalyst.Effects of the composition of the system,formic acid-H2O2 mole ratio,reaction temperature,reaction time and operating procedures on oxidation of styrene were investigated.The results indicated that the oxidation production of styrene was benzoic acid in formic acid-H2O2 system.With the increase in H2O2 dosage,reaction time and reaction temperature,the conversion of styrene increased and the selectivity to benzoic acid increased firstly and then decreased.The conversion and selectivity of styrene oxidation were also influenced by operating procedures and acids.Under the optimal conditions for styrene oxidation: H2O2 38.4 mmol(adding H2O2 in drop to the mixture of styrene and formic acid),styrene 6.4 mmol,formic acid 38.4 mmol,80 ℃ and 5 h,the conversion of styrene and selectivity to benzoic acid were 100% and 91.4%,respectively.