| 摘要 |
<p>A novel process for the preparation of 2,5-dihalo-3-nitro-benzoic acid and derivatives thereof is provided. The process comprises treating a compound of the formula WHEREIN X and Y are halogen, and Z is selected from the group consisting of halogen and anhydride, namely 2,5-dihalobenzoyloxy- without an intermediate hydrolysis step, with a sulfur-containing compound selected from the group of sulfur trioxide, oleum, chloro-sulfonic acid and mixtures thereof and a nitrating agent to produce 2,5-dihalo-3-nitrobenzoic acid. The process gives an increased yield of the desired 3-nitro- isomer product thereby decreasing the amount of undesired by-product isomers.</p> |
