Preparation method of hydroiodic acid

The invention discloses a preparation method of hydroiodic acid, which takes sodium iodide and pure water as raw materials and leads the reaction to be carried out at the presence of solid phosphorous acid, and the target product hydroiodic acid can be collected from an organic phase. The method ensures the purity of the hydroiodic acid to be more than 99% and the yield of the hydroiodic acid to be more than 90%. Compared with the prior art, the method uses the solid phosphorous acid to replace the traditional red phosphorus; in the rectification process of the hydroiodic acid, a stabilizing agent hypophosphorous acid is added, so that the product purity is effectively improved, and the potential safety hazard in the production process of the product can be reduced; the added stabilizing agent hypophosphorous acid can be recovered and reused, so that the production cost is reduced, and the method is beneficial to environmental protection; and the preparation method is simple in operation, stable in product quality, high in purity and suitable for continuous production.