Preparation method and device of acetyl chloride and hydroxy ethylene diphosphonic acid coproduction

Abstract

The present invention belongs to the field of chemical technology, in the concrete, it relates to a preparation method for simultaneously producing acetyl chloride and hydroxyethylidene diphosphonate and its equipment. Said method includes the following steps: adding glacial acetic acid and phosphorus trichloride according to the mole ratio of 3.0-3.2:1 in a reaction still, adopting continuous three-stage heating mode: 40-55 deg.C, 48-65 deg.C and 55-100 deg.C to make them produce reaction in the still so as to form hydroxyethylidene diphosphonate acetate and produce acetyl chloride vapor, making said acetyl chloride vapor be passed through rectification device and condensation device so as to obtain the liquid acetyl chloride whose content is greater than 99%.

Description

technical field [0001] The invention belongs to the technical field of chemical industry, and in particular relates to a preparation method and device for co-producing hydroxyethylene diphosphonic acid with acetyl chloride. Background technique [0002] Acetyl chloride is an important organic synthesis intermediate and acetylation reagent. Its acylation ability is stronger than that of acetic anhydride. It is widely used in organic synthesis and can be used in the production of pesticides, medicines, new electroplating complexing agents, and other fine organic synthesis Intermediate, it can be used in medicine to make 2,4-dichloro-5-fluoroacetophenone (intermediate of ciprofloxacin), ibuprofen, etc. Acetyl chloride is also a catalyst for the chlorination of carboxylic acids. [0003] The main industrial method of acetyl chloride is the glacial acetic acid-phosphorus trichloride method. Under normal pressure, add excess phosphorus trichloride slowly to glacial acetic acid, ...

AI Technical Summary

Problems solved by technology

[0012] 1. Due to the excessive phosphorus trichloride input in the production process, and the complex reaction of the process itself, there are more impurities in the finished acetyl chloride

[0013] 2. The finished acetyl chloride contains a small amount of phosphorus impurities, which will become turbid after long-term storage

[0014] 3. The by-product phosphorous acid contains a certain amount of hydroxyethylidene diphosphonic acid acetate, and the appearance is not good, which affects the application of the by-product phosphorous acid, and the economic benefit is poor

[0015] 4. In the process of purifying 98% acetyl chloride to 99%, the residual liquid in the kettle will be produced, which cannot be recycled, and three wastes will be produced

[0029] 1. A large amount of by-product hydrochloric acid is produced. In the case of poor sales of hydrochloric acid in the market, it will have an impact on expanding the production of HEDP, thereby affecting economic benefits

[0030] 2. During the dropping process, phosphorus trichloride reacts violently with water. If the operation is improper, a large amount of hydrogen chloride gas will be generated in the kettle, which will increase the pressure in the system and cause accidents easily.

[0031] 3. Under the condition of negative pressure, the material in the kettle is easy to escape, and the unit consumption of raw materials is 170.5kg of glacial acetic acid per ton of theoretical ton of 58% HEDP, and 785kg of 98.5% phosphorus trichloride.

The market price of acetyl chloride is about twice that of glacial acetic acid, and only 765 kg of glacial acetic acid can be obtained by consuming 1000 kg of acetyl chloride. It can be seen that this process wastes a part of the possible economic benefits

[0033] 5. The overall process time is too long and the energy consumption is too large

[0034] 6. In the production steps of dropping and heating, due to the complicated operation, it is impossible to produce high-quality products of HEDP stably

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