The invention relates to a method for synthesizing 
azelaic acid through single 
ionic liquid catalyzing 
oleic acid. The method comprises the following steps: 
oleic acid and a 1-(alpha-acid) methyl-3-methylimidazole 
phosphotungstic acid ionic liquid catalyst are mixed, then a 
hydrogen peroxide solution is added, the mixture is fully stirred, after the reaction, an oil layer is on the upper layer, a water lay is on the lower layer, and separation is easy; a separated aqueous phase is refrigerated and crystallized, 
white powder is precipitated, and 
azelaic acid solid is obtained through suction 
filtration and 
drying. According to the method, other chemical apparatuses are not required to be added in the whole reaction process, energy is saved, the 
reaction speed is accelerated, the time is saved, and no large number of 
organic solvent is required in the reaction, so that the method is green and environment-friendly. The method for synthesizing 
azelaic acid through single 
ionic liquid catalyzing 
oleic acid has the advantages that the reaction yield is high, one step reaction process is simple, the 
reaction system is easy to separated, the production cost is effectively reduced, and environment is protected.