Continuous preparation method of high-efficiency low-phosphorus scale inhibitor hydroxyethyl ethylenediamine trimethylene phosphonic acid

Abstract

The invention relates to a continuous preparation method of a high-efficiency low-phosphorus scale inhibitor hydroxyethyl ethylenediamine trimethylene phosphonic acid. Placing hydroxyethyl ethylenediamine, phosphorous acid and hydrochloric acid in a neutralization section layer of a reaction tower, and heating and mixing to obtain a mixed material; carrying out Mannich aminomethylation reaction on the obtained mixed material and a formaldehyde solution in a high-temperature tank of a single continuous reaction tower; distilling a product obtained by the reaction through a rotary evaporation pipe, feeding a liquid-phase product hydroxyethyl ethylenediamine trimethylene phosphonic acid into an intermediate kettle, adding reverse osmosis water for dilution, and pumping into a storage tank for storage; and condensing gas-phase formaldehyde and hydrochloric acid obtained by distillation for recycling. The single continuous reaction tower is adopted as a reaction container, and the preparation method of continuous feeding and continuous discharging is adopted, so that the occupied area is small, and the equipment investment is saved; the production cycle of the product is shortened, the reaction time is greatly shortened, the production efficiency and the productivity are improved, and the product quality is stable.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment chemical preparation, and particularly to a continuous preparation method of a highly efficient low-phosphorus scale inhibitor, hydroxyethyl ethylenediamine trimethylenephosphonic acid. Background Art

[0002] Currently, regarding the synthesis of hydroxyethyl ethylenediamine trimethylenephosphonic acid products using hydroxyethyl ethylenediamine, phosphorous acid, and formaldehyde as the main raw materials, the literature research reports can be referred to: Hu Shu, Deng Houfu, etc. Animal experimental study of 153Sm-hydroxyethyl ethylenediamine trimethylenephosphonic acid (HEDTMP). Chinese Journal of Nuclear Medicine, 2002, No.06; Hu Shu, Deng Houfu, etc. Animal experimental study of 188Re-hydroxyethyl ethylenediamine trimethylenephosphonic acid (188Re-HEDTMP). Proceedings of the First International Conference on Medical Imaging and Interventional Medicine, 2005, 233; Hu Shu, Deng Houfu, etc. Animal experimental study of 99mTc-hydroxyethyl ethylenediamine trimethylenephosphonic acid. Journal of Biomedical Engineering, 2010, No.04: 811-815.

[0003] Among water treatment chemicals, ethylenediamine tetramethylenephosphonic acid in the series of organic phosphorus products can be used not only in the water treatment field but also as a carrier for radioactive elements in the pharmaceutical industry for disease examination and treatment. The differences between hydroxyethyl ethylenediamine trimethylenephosphonic acid and ethylenediamine tetramethylenephosphonic acid are as follows: (1) Their phosphorus contents are different. The phosphorus contents of ethylenediamine tetramethylenephosphonic acid and hydroxyethyl ethylenediamine trimethylenephosphonic acid are 28.44% and 24.09% respectively; (2) One of the methylenephosphonic acids is replaced by a hydroxyethyl group. The advantages after replacement are as follows: In water treatment chemicals, both the methylenephosphonic acid group and the hydroxyl group in the hydroxyethyl group have the functions of inhibiting scale formation and reducing metal corrosion. However, the hydroxyl group also has a dispersing property, which can effectively disperse suspended solids and sludge in water to prevent their deposition and blockage of equipment; the defoaming property of the hydroxyl group can also eliminate bubbles and foams in water to ensure the normal operation of equipment.

[0004] Therefore, in the water treatment field, hydroxyethyl ethylenediamine trimethylenephosphonic acid is a multi-purpose scale inhibitor and dispersant, a strong chelating agent, and an excellent scale inhibitor for calcium carbonate and barium sulfate. The product is also easily soluble in water, non-toxic, has excellent tolerance to calcium and iron, and is heat-resistant. In the oilfield field, it is usually used as a scale and corrosion inhibitor to prevent scale formation, precipitation, and adhesion in production pipelines, completion systems, and processing facilities.

[0005] In the reports of the above-mentioned literature, an intermittent single-kettle synthesis method is adopted; after synthesis, it is mainly used for labeling hydroxyethyl ethylenediamine trimethylenephosphonic acid with samarium (153Sm), 188Re, and 99mTc to analyze its biological properties and explore the possibility of becoming a new radioactive bone imaging agent.

[0006] Patent CN220610398 U discloses a reaction kettle for hydroxyethyl ethylenediamine trimethylenephosphonic acid. Mainly, there are problems in the existing reaction kettle structure for chemical production, such as inconvenient temperature control and uneven mixing of reaction liquid and raw materials. A reaction kettle for hydroxyethyl ethylenediamine trimethylenephosphonic acid is proposed, which can control the temperature in real time and achieve full mixing of the reaction liquid and raw materials, and can stably heat the inside of the device to improve the reaction rate. At the same time, the buffer plate can prevent the problem that the internal structure is impacted and deformed due to the large impact force during feeding, thereby providing protection for the reaction kettle.

[0007] However, this method is still an intermittent single-kettle reaction, with problems such as long reaction time, low production capacity, low production efficiency, and large differences in product quality between different batches. Therefore, it is of great significance to improve the preparation method of hydroxyethyl ethylenediamine trimethylenephosphonic acid. Summary of the Invention

[0008] To solve the problems in the prior art, such as long reaction time, low production capacity, low production efficiency, and large differences in product quality between different batches in the synthesis of hydroxyethyl ethylenediamine trimethylenephosphonic acid products, the present invention provides a continuous preparation method for high-efficiency low-phosphorus scale inhibitor hydroxyethyl ethylenediamine trimethylenephosphonic acid. This preparation method adopts a continuous feeding and continuous discharging method, shortening the reaction time, improving the production efficiency and production capacity, with stable product quality, and being easy to realize intelligent and large-scale industrial production.

[0009] The purpose of the present invention is to provide a continuous preparation method for high-efficiency low-phosphorus scale inhibitor hydroxyethyl ethylenediamine trimethylenephosphonic acid, including the following steps:

[0010] Put hydroxyethyl ethylenediamine, phosphorous acid, and hydrochloric acid into the neutralization section layer of the reaction tower, heat and mix to obtain a mixed material;

[0011] Perform Mannich aminomethylation reaction on the obtained mixed material and formaldehyde solution in the high-temperature tank of a single continuous reaction tower;

[0012] Distill the product obtained from the reaction through a rotary evaporation tube. The liquid-phase product hydroxyethyl ethylenediamine trimethylenephosphonic acid enters the intermediate kettle, and at the same time, it is diluted with reverse osmosis water and pumped into the storage tank for storage; the gaseous formaldehyde and hydrochloric acid distilled are condensed and recycled.

[0013] In some embodiments of the present invention, the molar ratio of hydroxyethyl ethylenediamine, phosphorous acid, and hydrochloric acid is 1:(3 - 4):(2 - 3).

[0014] In some embodiments of the present invention, the concentration of hydroxyethyl ethylenediamine is above 99.0 wt%.

[0015] In some embodiments of the present invention, the concentration of phosphorous acid is 50 wt% - 80 wt%.

[0016] In some embodiments of the present invention, the concentration of hydrochloric acid is greater than or equal to 31 wt%.

[0017] In some embodiments of the present invention, the temperature of the heating mixture is less than 60 °C.

[0018] In some embodiments of the present invention, the concentration of the formaldehyde solution is 37.0 wt% - 44 wt%.

[0019] In some embodiments of the present invention, the molar ratio of hydroxyethyl ethylenediamine to formaldehyde is 1:(3 - 4).

[0020] In some embodiments of the present invention, the temperature of the Mannich aminomethylation reaction is 90 - 130 °C, and the reaction time is 60 - 120 minutes.

[0021] The above technical solution of the present invention has the following advantages compared with the prior art:

[0022] The present invention adopts a continuous feeding and continuous discharging method, which occupies less floor area and saves equipment investment; shortens the product production cycle, greatly shortens the reaction time, improves production efficiency and production capacity, and the product quality is stable; can make full use of the heat generated by the reaction for recycling, reduces costs, and is easy to realize intelligent and large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to make the content of the present invention easier to be clearly understood, the following further describes the present invention in detail according to the specific embodiments of the present invention in conjunction with the drawings, wherein,

[0024] Figure 1 is a simple schematic diagram of a one-tower reaction device of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0025] The present invention will be further described below in conjunction with the drawings and specific embodiments, so that those skilled in the art can better understand the present invention and be able to implement it, but the embodiments cited do not limit the present invention.

[0026] Example 1

[0027] This example provides a continuous preparation method of high-efficiency low-phosphorus scale inhibitor hydroxyethyl ethylenediamine trimethylene phosphonic acid, and the specific steps are as follows:

[0028] (1) Prepare materials according to the molar ratio of hydroxyethyl ethylenediamine, phosphorous acid, hydrochloric acid, and formaldehyde of 1:3.0:2.0:3.0.

[0029] (2) First, carry out the neutralization reaction: Hydroxyethyl ethylenediamine, phosphorous acid, and hydrochloric acid enter the neutralization section layer from their respective storage tanks respectively, mix and undergo a neutralization reaction, and use chiller water to control the temperature to ensure that the temperature is less than 60 °C. When the reaction neutralization liquid accumulates to 2 / 3 of the position in the neutralization liquid level tank, the discharge valve automatically opens, the material overflows, and flows upward to the high-temperature tank. When the high-temperature tank senses the material, the formaldehyde storage tank automatically opens the feed valve, and formaldehyde automatically flows into the high-temperature tank to react with the neutralized material, controlling the reaction temperature at 110 °C; when the synthesized product reaches 2 / 3 of the liquid level tank, it flows to the rotary evaporation tube. The gaseous formaldehyde and hydrochloric acid distilled from the evaporation tube are recycled after condensation to obtain the reaction product hydroxyethyl ethylenediamine trimethylene phosphonic acid; the liquid-phase product hydroxyethyl ethylenediamine trimethylene phosphonic acid enters the intermediate kettle (equipped with a weighing scale), and at the same time, reverse osmosis water is added for dilution and then pumped into the storage tank.

[0030] (3) Detect the corresponding indicators of the reaction product. The residual amount of phosphorous acid is 0.61%, the conversion rate of phosphorous acid is 99.39%, and the reaction rate is 745.5 kg / h.

[0031] Example 2

[0032] This example provides a continuous preparation method of high-efficiency low-phosphorus scale inhibitor hydroxyethyl ethylenediamine trimethylene phosphonic acid, and the specific steps are as follows:

[0033] (1) Prepare materials according to the molar ratio of hydroxyethyl ethylenediamine, phosphorous acid, hydrochloric acid, and formaldehyde of 1:3.1:2.2:3.1.

[0034] (2) First, carry out the neutralization reaction. Hydroxyethyl ethylenediamine and phosphorous acid are mixed and enter the neutralization section layer from their respective storage tanks to undergo a neutralization reaction, and use chiller water to control the temperature to ensure that the temperature is less than 60 °C. When the reaction neutralization liquid accumulates to 2 / 3 of the position in the neutralization liquid level tank, the discharge valve automatically opens, the material overflows, and flows upward to the high-temperature tank. When the high-temperature tank senses the material, the formaldehyde storage tank automatically opens the feed valve, and formaldehyde automatically flows into the high-temperature tank to react with the neutralized material, controlling the reaction temperature at 110 °C; when the synthesized product reaches 2 / 3 of the liquid level tank, it flows to the rotary evaporation tube. The gaseous formaldehyde and hydrochloric acid distilled from the evaporation tube are recycled after condensation to obtain the reaction product hydroxyethyl ethylenediamine trimethylene phosphonic acid; the liquid-phase product hydroxyethyl ethylenediamine trimethylene phosphonic acid enters the intermediate kettle (equipped with a weighing scale), and at the same time, reverse osmosis water is added for dilution and then pumped into the storage tank.

[0035] (3) Detect the corresponding indicators of the reaction product. The residual amount of phosphorous acid is 0.78%, the conversion rate of phosphorous acid is 99.22%, and the reaction rate is 833 kg / h.

[0036] Example 3

[0037] This embodiment provides a continuous preparation method of the high-efficiency low-phosphorus scale inhibitor hydroxyethyl ethylenediamine trimethylenephosphonic acid, and the specific steps are as follows:

[0038] (1) Prepare materials according to the molar ratio of hydroxyethyl ethylenediamine, phosphorous acid, hydrochloric acid, and formaldehyde of 1:3.2:2.5:3.2.

[0039] (2) First, carry out a neutralization reaction. Mix hydroxyethyl ethylenediamine and phosphorous acid and enter the neutralization section layer from their respective storage tanks to carry out the neutralization reaction, and use ice machine water to control the temperature to ensure that the temperature is less than 60°C. When the reaction neutralization liquid accumulates to the 2 / 3 position in the neutralization liquid level tank, the discharge valve automatically opens, and the material overflows and flows upward to the high-temperature tank. When the high-temperature tank senses the presence of material, the formaldehyde storage tank automatically opens the feed valve, and formaldehyde automatically flows into the high-temperature tank to react with the neutralized material, controlling the reaction temperature at 110°C; when the synthesized product reaches the 2 / 3 of the liquid level tank, it flows to the rotary evaporation tube. The gaseous formaldehyde and hydrochloric acid distilled from the evaporation tube are recycled after condensation to obtain the reaction product hydroxyethyl ethylenediamine trimethylenephosphonic acid; the liquid-phase product hydroxyethyl ethylenediamine trimethylenephosphonic acid enters the intermediate kettle (equipped with a weighing scale), and at the same time, reverse osmosis water is added for dilution and then pumped into the storage tank.

[0040] (3) Detect the corresponding indicators of the reaction product. The residual amount of phosphorous acid is 0.99%, the conversion rate of phosphorous acid is 99.01%, and the reaction rate is 850.5 kg / h.

[0041] Comparative Example 1

[0042] This comparative example provides a continuous preparation method of the high-efficiency low-phosphorus scale inhibitor hydroxyethyl ethylenediamine trimethylenephosphonic acid, and the specific steps are as follows:

[0043] (1) Carry out batch single-kettle (10-ton reaction kettle) production preparation according to the molar ratio of hydroxyethyl ethylenediamine, phosphorous acid, hydrochloric acid, and formaldehyde of 1:3.0:2:0:3.0.

[0044] (2) First, pump phosphorous acid and hydrochloric acid into the reaction kettle from their respective storage tanks, and dropwise add hydroxyethyl ethylenediamine to carry out the neutralization reaction, controlling the temperature in the kettle to be less than 60°C and the neutralization time to be 6 hours; after the neutralization reaction is completed, raise the temperature to 90°C, start to dropwise add formaldehyde, the dropping temperature is 110°C, and the dropping time is 5 hours; after the dropping is completed, keep the temperature under reflux for 3 hours; after the heat preservation is over, carry out distillation until no liquid flows out, and the distillation time is 12 hours; after the distillation is over, cool down to below 60°C, add reverse osmosis water for dilution, and finally pump it into the storage tank to obtain the product hydroxyethyl ethylenediamine trimethylenephosphonic acid.

[0045] Detect the indicators. The residual amount of phosphorous acid is 0.73%, the conversion rate of phosphorous acid is 99.27%, and the reaction rate is 166.67 kg / h.

[0046] Performance experiment

[0047] The hydroxyethyl ethylenediamine trimethylenephosphonic acid, aminotrimethylenephosphonic acid, hydroxyethane-1,1-diphosphonic acid, and 2-phosphono-1,2,4-tricarboxybutane (commercially available product) obtained from the examples and comparative examples were weighed (calculated based on dry matter), diluted in mass, and the dosage was 5 ppm. After being placed at 80 °C for 10 hours, the static scale inhibition rate was measured according to "GB / T 16632-2019 Determination of Scale Inhibition Performance of Water Treatment Agents - Calcium Carbonate Deposition Method". The results are shown in the following table.

[0048] Table 1

[0049]

[0050] As can be seen from Table 1, under the same conditions, the hydroxyethyl ethylenediamine trimethylenephosphonic acid product shows a relatively high static scale inhibition rate, and its values are all greater than 90%. In contrast, the static scale inhibition rates of aminotrimethylenephosphonic acid, hydroxyethane-1,1-diphosphonic acid, and 2-phosphono-1,2,4-tricarboxybutane are significantly lower. Thus, the hydroxyethyl ethylenediamine trimethylenephosphonic acid product has significant advantages in terms of static scale inhibition performance.

[0051] Obviously, the above examples are merely illustrations for clear explanation and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of this invention.

Claims

1. A continuous preparation method of a high-efficiency low-phosphorus scale inhibitor hydroxyethylethylenediaminetrimethylenephosphonic acid, characterized in that: The following steps are involved: Putting hydroxyethylethylenediamine, phosphorous acid and hydrochloric acid in a neutralization section of a reaction tower, heating and mixing to obtain a mixed material; The obtained mixed material and formaldehyde solution are subjected to Mannich amine methylation reaction in a single continuous reaction tower high temperature tank; The product obtained by the reaction is distilled through a rotary evaporator, and the liquid product hydroxyethylethylenediaminetri(methylenephosphonic acid) enters the intermediate kettle, and is diluted with reverse osmosis water and pumped into a storage tank for storage; the gaseous formaldehyde and hydrochloric acid obtained by the distillation are condensed and recycled.

2. The continuous preparation method of the high-efficiency low-phosphorus scale inhibitor hydroxyethylethylenediaminetrimethylenephosphonic acid according to claim 1 is characterized in that: The molar ratio of the hydroxyethylethylenediamine, phosphorous acid and hydrochloric acid is 1:(3-4):(2-3).

3. The continuous preparation method of the high-efficiency low-phosphorus scale inhibitor hydroxyethylethylenediaminetrimethylenephosphonic acid according to claim 1 is characterized in that: The concentration of the hydroxyethylethylenediamine is 99.0% or more.

4. The continuous preparation method of the high-efficiency low-phosphorus scale inhibitor hydroxyethylethylenediaminetrimethylenephosphonic acid according to claim 1 is characterized in that: The concentration of phosphorous acid is 50 wt% to 80 wt%.

5. The continuous preparation method of the high-efficiency low-phosphorus scale inhibitor hydroxyethylethylenediaminetrimethylenephosphonic acid according to claim 1 is characterized in that: The concentration of the hydrochloric acid is greater than or equal to 31 wt %.

6. The continuous preparation method of the high-efficiency low-phosphorus scale inhibitor hydroxyethylethylenediaminetrimethylenephosphonic acid according to claim 1 is characterized in that: The temperature of the heating mixture is less than 60°C.

7. The continuous preparation method of the high-efficiency low-phosphorus scale inhibitor hydroxyethylethylenediaminetrimethylenephosphonic acid according to claim 1 is characterized in that: The concentration of the formaldehyde solution is 37.0 wt% to 44 wt%.

8. The continuous preparation method of the high-efficiency low-phosphorus scale inhibitor hydroxyethylethylenediaminetrimethylenephosphonic acid according to claim 1 is characterized in that: The molar ratio of hydroxyethylethylenediamine to formaldehyde is 1:(3-4).

9. The continuous preparation method of the high-efficiency low-phosphorus scale inhibitor hydroxyethylethylenediaminetrimethylenephosphonic acid according to claim 1, characterized in that: The temperature of the Mannich amine methylation reaction is 90-130°C and the reaction time is 60-120 minutes.

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