Industrial production method of high purity 2-nitro-4-methylsulfonylbenzoic acid

The invention relates to an industrial production method of high purity 2-nitro-4-methylsulfonylbenzoic acid, which comprises the following steps: a)generating a crude product by oxidizing o-nitro-methylsulfonyl toluene through nitric acid; b)adding an alkalescence substance for neutralizing; c)reducing by a reducing agent; d)centrifuging, filtering and separating to obtain mother liquor; e)performing acidification; f)obtaining a solid product 2-nitro-4-methylsulfonylbenzoic acid wet product after centrifuging, filtering and separating; and g)drying to obtain the final qualified product. The production method can realize the large scale industrial production.