Process for preparing phosphorous acid by hydrolyzing phosphorus trichloride

Abstract

The invention relates to a process for preparing phosphorous acid by hydrolyzing phosphorus trichloride, and in particular relates to a process for preparing phosphorous acid by hydrolyzing phosphorus trichloride under a mild reaction condition. According to the process, phosphorus trichloride and a hydrogen chloride solution are subjected to hydrolysis reaction in sequence in at least four stages of cascade reaction vessels under the condition that the temperature is 65-85 DEG C and the pressure is not more than 0.1Mpa to generate a phosphorous acid solution and gaseous hydrogen chloride. In the process, the phosphorus trichloride reacts with the water in a hydrochloric acid solution, the phosphorus trichloride is subjected to an exothermic reaction, the temperature of the process can reduce the hydrolysis rate to ensure that the reaction is performed mildly, and at least four stages of cascade bubbling reactions are adopted by the process, so that the utilization ratio of raw materials is improved, the phosphorus trichloride in the reaction vessel of the previous stage can enter the reaction vessel of the next stage, the content of the phosphorus trichloride in the reaction vessel of the previous stage is reduced in other ways, the intensity of the reaction is reduced again, the production safety is improved, and the service life of equipment is prolonged.

Description

Technical field [0001] The present invention involves a metal phosphoric acid technology, especially a gently reactive metrochloride hydrolysis process. Background technique [0002] Ach phosphoric acid is a common chemical raw material for chemical production. There are many methods of preparation, such as: trichloride hydrolysis method: direct hydrolysis of phosphorus and water, hydrogen chloride gases;(CN1187459): The high -temperature hydrochloric hydraulic hydrodiacotic acid is used to prepare adly phosphate with a vitamin.Wang Zhengyan reported in China's "chloro -alkali industry" in the 11th issue of 1989, "Synthetic phosphoric acid synthesis of methamphetamine hydrolysis method", but the article uses intermittent kettle reactions. The hydrolysis reactions with water chloride and water are difficult to control. The temperature is difficult to control.For a long time, it is necessary to slowly control the implementation of three -phosphorus.EssenceIf the hydrogen chloride a...

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Problems solved by technology

However, the reaction equipment is special, and the process is more complicated. The enterprise invests a lot in the early stage of equipment, and the cost of equipment maintenance in the later stage is high.

[0004] In the patent document with the publication number CN102249202A, a process for preparing phosphorous acid by hydrolysis of phosphorus trichloride is provided. Through the rapid and efficient absorption of hydrogen chloride in the hydrolysis product of phosphorus trichloride, the speed of the hydrolysis reaction is improved, and the production capacity, but its hydrolysis reaction equipment is susceptible to corrosion, and the temperature of the hydrolysis reaction is difficult to control, and production safety has not been effectively guaranteed

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