Hydroxyethylenediphosphonic acid production equipment and method

Abstract

The invention discloses a method for producing etidronic acid, relating to an improved technology of the production process of a water treatment agent, namely, etidronic acid and belonging to the technical field of chemical engineering. According to the method, hydrogen chloride is introduced into the raw materials for reaction, so that water dissolution heat for hydrogen chloride is reduced in the hydrolysis process of phosphorus trichloride, furthermore, the hydrolysis intensity of the phosphorus trichloride is inhibited, the reaction can be carried out stably, and side reactions of hydrolysis of acetylchloride also can be reduced. The method has the beneficial effects that the reaction can be carried out smoothly at the beginning, side reactions are reduced, and the production is relatively high; in middle stage, the reaction of phosphorous acid can be accelerated, so that the reaction time can be shortened obviously, the recycled acetylchloride and acetic acid and a cleaning solution can be reused, and the quality of byproduct hydrochloric acid is improved.

Description

Technical field [0001] The invention relates to equipment and a method used in the production process of a water treatment agent-hydroxyethylene diphosphonic acid, belonging to chemical equipment and a method. Background technique [0002] Hydroxyethylene diphosphonic acid (HEDP) is currently widely used water treatment agent, mainly used in industrial circulating water as scale and corrosion inhibitor, electroplating metal complexing agent, detergent auxiliaries and photographic printing and dyeing auxiliaries. [0003] At present, industrial production methods generally use glacial acetic acid and phosphorus trichloride as raw materials, or take glacial acetic acid, phosphorus trichloride and water as raw materials, and use stepwise heating and hydrolysis to produce hydroxyethylene diphosphonic acid. Among them, glacial acetic acid and phosphorus trichloride are used as raw materials, and there is an excessive amount of glacial acetic acid during the production process, and the g...

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Problems solved by technology

Among them, glacial acetic acid and phosphorus trichloride are used as raw materials. There is an excessive amount of glacial acetic acid in the production process, and the glacial acetic acid needs to be recovered later, resulting in an excessive volume-to-output ratio and a waste of production capacity.

Using glacial acetic acid, water, and phosphorus trichloride as raw materials, there are severe hydrolysis in the initial stage of the reaction, the reaction is not stable, and it is difficult to control the phenomenon

No matter which method, in the reaction process, in order to reduce the content of phosphorous acid, the method of prolonging the reaction time and allowing acetyl chloride to fully reflux is usually adopted. Due to the low boiling point of acetyl chloride, it is difficult to stay in the reactor for a long time in the later stage, so Make the reaction time too long, acetyl chloride volatilization loss and other disadvantages

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