Production method of hydrogen iodide

Abstract

The invention discloses a production method of hydrogen iodide, which adopts a red phosphorus method and comprises a reacting step, a filtering step and a distilling step sequentially. In the reacting step, deionized water is added into reaction equipment; after red phosphorus and iodine are added, the weight ratio of the reaction material liquid is measured and is controlled to be between 1.2 and 1.4; and hydroiodic acid steam is absorbed by a water spraying pump. The filtering step includes two times of filtering. The production method provided by the invention solves the problem of difficult realization of mass production, and avoids the occurance of explosion, has high production efficiency and contributes to environmental protection at the same time.

Description

technical field [0001] The present invention relates to a kind of production method of hydrogen iodide. Background technique [0002] The aqueous solution of hydrogen iodide is called hydroiodic acid, chemical formula HI, strong acid, the most acidic of non-radioactive anaerobic acids, easily decomposed into iodine and hydrogen in the air, and is the most reductive among hydrohalic acids. In industry, its preparation method generally has the following three kinds: [0003] One is the direct synthesis method, that is, direct synthesis with hydrogen and iodine through platinum black or platinum asbestos catalysis: H 2 +I 2 = 2HI, this reaction is reversible, this method is to react under the condition above 500 ℃, the reaction conditions are harsh, the requirements for equipment are high, the one-time investment of equipment is large, and the price of the catalyst Pt required by it is expensive, making the whole The cost of the synthesis process is relatively high; [0004...

AI Technical Summary

Problems solved by technology

[0003] One is the direct synthesis method, that is, direct synthesis with hydrogen and iodine through platinum black or platinum asbestos catalysis: H 2 +I 2 =2HI, this reaction is reversible, this method is to react under the condition above 500°C, the reaction conditions are harsh, the requirements for equipment are high, the one-time investment of equipment is large, and the price of the catalyst Pt required by it is expensive, making the whole The cost of the synthesis process is relatively high;

[0004] The second is the hydrogen sulfide method, that is, the replacement reaction of hydrogen sulfide and iodine occurs, and the H 2 S+I 2 =2HI+S↓, the disadvantage of this method is that the preparation speed of hydrogen sulfide gas is slow, the process line is long, and if the hydrogen sulfide gas is not properly controlled, it is easy to leak, which will poison the workers and is not easy to scale production;

[0006] First of all, it is prone to explosion, and there is a great potential safety hazard. In the reaction process, the reaction essentially includes the following two steps:

[0007] Compound 2P+3I 2 = 2PI 3 , Hydrolyzed PI 3 +3H 2 O=2H 3 PO 3 +3HI, on the one hand, due to the intermediate product PI 3 Unstable in nature, prone to explosion, especially in large-scale production, explosion is more likely to occur, and the hazard is great;

[0008] Secondly, it is difficult to scale up and the production efficiency is low

Excessive red phosphorus is often added in the reaction, resulting in unclean filtration of red phosphorus, and the residual red phosphorus will also explode during distillation. In order to filter the excess red phosphorus, it is often necessary to stand overnight, which limits its large-scale production , can only be prepared in a small amount at a time, and it takes a long time and the efficiency is low, which cannot meet the needs of large-scale production. In addition, at present, deionized water is generally used to react with red phosphorus and iodine, and the reaction starts very slowly, which is also an important reason for the low efficiency of the entire production process. reason

[0009] In addition, during large-scale production, during the production process, especially during the reaction process, the generated HI is easy to leak and cause environmental pollution.