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A kind of continuous production method of hydroxyethylene diphosphonic acid crystal

A technology of hydroxyethylene diphosphonic acid and its production method, which is applied in the field of continuous production of hydroxyethylene diphosphonic acid crystals, and can solve problems affecting product market application and promotion, limiting product capacity scale, and long equipment occupation period, etc. problems, to achieve the effect of rapid separation and purification, shortened production cycle, and stable product quality

Active Publication Date: 2021-05-07
SHANDONG TAIHE WATER TREATMENT TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The existing disclosed methods for preparing hydroxyethylene diphosphonic acid solids or crystals all adopt traditional intermittent single-pot operation, which is unfavorable for the stability of product quality between batches; at the same time, because the crystallization process is affected by many factors The slow physical process of the impact and the long period of equipment occupation greatly limit the production capacity of this type of product and seriously affect the market application and promotion of the product

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] The hydroxyethylene diphosphonic acid liquid with an active content of 51.34% was preheated to 82 °C by a graphite heater, and the hydrogen chloride and a small amount of water vapor in the system were removed by gas-liquid separation, and then continuously poured into the still at a constant speed of 250 kg / h. ; Continue feeding for 1 hour until the material volume accounts for about one-third of the volume of the still body, turn on the still and stir, maintain the system temperature at 125 ± 1 °C, and rapidly evaporate and concentrate under the condition of -0.06MPa negative pressure; continuous feeding for 3 hours After that, the active content of the material in the still is 70.28% and the volume of the material in the still reaches the set transfer level. The valve at the bottom of the still and the transfer pump are automatically opened to continuously transfer the material cooled to 62°C at a flow rate of 282kg / h. The crystallization of the first-stage crystalliz...

Embodiment 2

[0036]The hydroxyethylene diphosphonic acid liquid with an active content of 60.29% was preheated to 90 ° C by a graphite heater, and the hydrogen chloride and a small amount of water vapor in the system were removed by gas-liquid separation, and then continuously poured into the still at a constant speed of 200 kg / h ; Continue feeding for 1.5 hours until the material volume accounts for about one-third of the volume of the still body, turn on the still and stir, maintain the system temperature at 130 ± 1 °C, and rapidly evaporate and concentrate under the condition of -0.04MPa negative pressure; continuous feeding for 4 hours After that, the active content of the material in the still is 70.04% and the volume of the material in the still reaches the set transfer liquid level. The valve at the bottom of the still and the transfer pump are automatically opened to continuously transfer the material cooled to 65°C at a flow rate of 250kg / h. The crystallization of the first-stage c...

Embodiment 3

[0038] The hydroxyethylene diphosphonic acid liquid with an active content of 60.57% was preheated to 75 ℃ by a graphite heater, and the hydrogen chloride and a small amount of water vapor in the system were removed by gas-liquid separation. ; When the material volume accounts for about one-third of the volume of the kettle body, the distillation kettle is turned on and stirred, and the temperature of the system is maintained at 128 ± 2 °C. Under the condition of -0.04MPa negative pressure, it is rapidly evaporated and concentrated. After 2.8 hours of continuous feeding, The active content of the material in the still is 70.08% and the volume of the material in the still reaches the set transfer level, the valve at the bottom of the still and the transfer pump are automatically opened, and the material cooled to 70°C is continuously transferred to the first batch at a flow rate of 320kg / h. The crystallization is carried out in the crystallization kettles of all levels, and is c...

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Abstract

The invention provides a continuous production method of hydroxyethylene diphosphonic acid crystals. The specific operation method includes: the liquid product of hydroxyethylidene diphosphonic acid with an active content of 50-65% is preheated and separated from the gas and liquid, and then poured into the distillation kettle continuously at a constant speed; when the active content of the material is ≥ 70% after distillation and concentration, After the high-temperature material is condensed, the automatic material transfer is completed step by step between the crystallization kettles connected in series, and the continuous crystallization is carried out step by step under the conditions of stirring and natural cooling; finally, the temperature of the n-stage crystallization kettle is cooled by circulating condensation and the system temperature is maintained at 20 ±2°C. After full crystallization, separation and drying treatment, the hydroxyethylidene diphosphonic acid crystal product with active content ≥ 98% is obtained. The present invention changes the traditional single-pot closed crystallization method into an assembly line crystallization method that is more suitable for industrialization, and the prepared crystal grain size is suitable. During the crystallization process, crystallization aids and crystal nuclei are not added, and there is no detonation, which is suitable for industrialization.

Description

technical field [0001] The invention belongs to the technical field of fine chemical production, and in particular relates to a continuous production method of hydroxyethylene diphosphonic acid crystals. Background technique [0002] Hydroxyethylidene diphosphonic acid (HEDP for short) has a very stable C-P bond in its molecule, the bond energy is 246kJ / mol, high temperature resistance, and has a good scale inhibition effect on calcium carbonate, hydrated iron oxide and calcium phosphate in water , is an important scale inhibitor and dispersant. Because HEDP can form stable complexes with various metal ions such as iron, copper, and zinc, and can dissolve oxides on the metal surface, it can be used as a complexing agent in the cyanide-free electroplating industry; in addition, because HEDP has good corrosion inhibition Anti-scaling effect and passivation of metal surface, high-purity HEDP products can be used for circuit board cleaning and metal surface treatment in the ele...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07F9/38
CPCC07F9/3808
Inventor 程终发王燕平齐晓婧宋盟盟王宁宁刘全华
Owner SHANDONG TAIHE WATER TREATMENT TECH CO LTD
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