A kind of synthetic method of multistage unpowered bubbling type hydroxyethylene diphosphonic acid

Abstract

The invention belongs to the technical field of chemical industry production technologies, and particularly relates to a synthesis method for multistage power-free bubble-type (hydroxyethylidene)diphosphonic acid. The synthesis method includes the steps that phosphorus trichloride and acetic acid is subjected to a step-by-step overflowing reaction in a reaction tower with at least 6 stages connected in series at the temperature of 90 DEG C to 150 DEG C and the pressure smaller than or equal to 0.5 MPa, the product is hydrolyzed in a hydrolysis kettle, and the (hydroxyethylidene)diphosphonic acid is generated. According to the synthesis method, operating is easy, an esterification reaction is carried out in a multistage-series mode, reacting is thorough, the utilization ratio of raw materials is increased, every-stage reaction is mildly carried out, repetitive condensation operation does not exist in acetyl chloride gas, and the reaction temperature is easy to control.

Description

technical field [0001] The invention belongs to the technical field of chemical production technology, and in particular relates to a multi-stage non-powered bubbling method for synthesizing hydroxyethylene diphosphonic acid. Background technique [0002] There are many preparation methods for hydroxyethylidene diphosphonic acid. In the industry, glacial acetic acid and phosphorus trichloride are usually acylated, and then produced by condensation of acylated products and phosphorus trichloride hydrolyzate: add measured water and glacial acetic acid In the reaction kettle, after stirring evenly, add phosphorus trichloride dropwise, and control the reaction temperature at 40-80°C. The by-product hydrogen chloride gas is condensed and sent to the absorption tower to recover hydrochloric acid. Spilled acetyl chloride and acetic acid are condensed and returned to the reactor to continue to participate in the reaction. After the phosphorus trichloride is dropped, the temperatur...

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Problems solved by technology

[0008] In this production process, acetyl chloride is very easy to vaporize and overflow, and acetyl chloride absorbs heat when it vaporizes, and condenses and releases heat, resulting in an unstable reaction temperature, which requires repeated heating of the reactor with steam and repeated cooling of acetyl chloride with refrigerant water, which not only consumes a lot of energy, but also only Batch production mode can be adopted

At the same time, in the existing technology, glass-lined equipment that is easily damaged is mostly used as the main reactor, which not only has a high maintenance rate of the equipment, but also has a large safety and environmental protection risk during replacement.

[0009] The patent document with the application publication number CN101016315A discloses a continuous synthesis process of hydroxyethylene diphosphonic acid. This process uses different equipment reactors and does not use water as a raw material. It is a method for the production of acetyl chloride and co-production of HEDP Process mode, which uses more types of equipment, and the operation is more complicated, which inevitably increases the production cost

[0010] The patent document with the application publication number CN105622667A discloses a production method for the co-production of acetyl chloride from hydroxyethylene diphosphonic acid. The process adopts the mainstream process of the prior art, the reaction temperature is unstable, and energy consumption is wasted

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