Abstract: A new production technology of high-quality trimellitic anhydride with the liquid-phase air-oxidation from [BF]1,2,4-[BFQ]trimethylbenzene was developedA dehydration column evaporator was used in the process for guaranteeing an optimized experimental condition for 1,2,4-trimethylbenzene oxidationA high quality crystalline trimellitic anhydride with more than 99% purity was obtained by the use of a new electromagnetic frequency inductively coupled bidirectional heater and a nano-filter in the process, resulting in the reduction of side reactions and elimination of insoluble impuritiesThe merits of low unit consumption, high quality product and less environmental pollution demonstrate its potential application to non-hazardous and environmental friendly production.