Alkyl epoxy carboxylate compound scale and corrosion inhibitor, preparation method and application

Abstract

The compound scale and corrosion inhibitor of alkyl epoxy carboxylate disclosed by the present invention is composed of the following raw material components according to mass percentage: 80-90% of alkyl tri-epoxy carboxylate and 10-20% of alkyl penta-epoxy carboxylate; The present invention also discloses a preparation method of the compound scale and corrosion inhibitor of alkyl epoxy carboxylate: Step 1, dissolve fatty alcohol polyoxyethylene ether A and sodium chloroacetate, add sodium hydroxide and react to obtain alkyl tri-epoxy carboxylate; Step 2, dissolve fatty alcohol polyoxyethylene ether B and sodium chloroacetate, add sodium hydroxide and react to obtain alkyl penta-epoxy carboxylate; Step 3, mix the alkyl tri-epoxy carboxylate and the alkyl penta-epoxy carboxylate to obtain the compound scale and corrosion inhibitor of alkyl epoxy carboxylate. The present invention also discloses the application of the compound scale and corrosion inhibitor of alkyl epoxy carboxylate. The compound scale and corrosion inhibitor of alkyl epoxy carboxylate of the present invention can scale inhibition, dispersion and corrosion inhibition and anti-corrosion for the mixed calcium scale system. At the same time, the preparation process is simple, the practicability is strong, and it is biodegradable.

Description

Technical Field

[0001] The present invention belongs to the technical field of the preparation of green water treatment agents, and relates to a compound scale and corrosion inhibitor of alkyl epoxy carboxylate. The present invention also relates to a preparation method of the above-mentioned compound scale and corrosion inhibitor of alkyl epoxy carboxylate, and the present invention also relates to the application of the compound scale and corrosion inhibitor of alkyl epoxy carboxylate. Background Art

[0002] Heat exchangers are important components in industrial circulating cooling water systems, and crystalline fouling is the main reason for reducing the low working efficiency of heat exchangers. Especially in the production of petroleum, natural gas, hydrometallurgy processes and the detergent industry, crystalline fouling mainly reduces heat transfer and deteriorates the performance of process equipment. At the same time, combined with biological slime and corrosion products, it will cause problems such as pipe corrosion in heat exchangers, resulting in increased operation and maintenance costs. At present, common industrial scale inhibitors include phosphorus-rich scale inhibitors such as inorganic phosphates and organic phosphonic acids. Although they have excellent scale inhibition performance, the presence of phosphorus makes them unable to meet the increasingly strict environmental protection requirements. Green water treatment agents mainly include natural polymer polymers and synthetic polymers. Common natural green polymer scale inhibitors mainly include lignin, cellulose, starch, tannin and their derivatives, etc., which are the first type of scale inhibitors applied to cooling water systems. Although natural polymer water treatment agents are widely sourced, non-toxic, harmless and easily biodegradable, the performance of these polymers is unstable, easily decomposed under high temperature and high alkalinity conditions, and has disadvantages such as large dosing amounts and high impurity contents. Although many environmentally friendly water treatment agents have emerged, due to their complex production processes and high equipment requirements, the prices are relatively high, and good economic benefits cannot be achieved. The compounding of scale inhibitors can achieve scale inhibition efficiently, at low cost and in an environmentally friendly manner.

[0003] Alkyl Epoxy Carboxylate (AEC) is a non-phosphorus scale inhibitor produced by BetzDearborn Company in the United States. It has the characteristics of non-toxicity, chlorine resistance, temperature resistance and excellent calcium carbonate scale inhibition performance. It can replace organic phosphate scale inhibitors and is regarded as the most promising new type of environmentally friendly scale inhibitor. However, at present, the synthesis route of AEC is relatively complex, the synthesis conditions are demanding and the yield is relatively low. At the same time, its thermal stability is relatively poor and the scale inhibition efficiency is relatively low when used alone in cooling water systems with high pH value, high alkalinity, high hardness and high concentration ratio. Therefore, there is a need for a scale and corrosion inhibitor with good thermal stability and scale inhibition effect in cooling water systems with high pH value, high alkalinity, high hardness and high concentration ratio, and having corrosion inhibition and anti-corrosion functions. Summary of the Invention

[0004] The first object of the present invention is to provide a compound scale and corrosion inhibitor of alkyl epoxy carboxylate, which has the characteristics of scale and corrosion inhibition and anti-corrosion for a mixed calcium scale system.

[0005] The second object of the present invention is to provide a preparation method of a compound scale and corrosion inhibitor of alkyl epoxy carboxylate.

[0006] The third object of the present invention is to provide the application of the above compound scale and corrosion inhibitor of alkyl epoxy carboxylate.

[0007] The technical solution adopted by the present invention is that the compound scale and corrosion inhibitor of alkyl epoxy carboxylate is composed of the following raw material components according to mass percentage:

[0008] 80-90% of alkyl triepoxy carboxylate and 10-20% of alkyl pentaepoxy carboxylate, and the sum of the mass percentages of the above components is 100%; the number average molecular weight of alkyl triepoxy carboxylate is 350-400 g / mol, and the number average molecular weight of alkyl pentaepoxy carboxylate is 450-500 g / mol.

[0009] The characteristics of the present invention also lie in that the structural formula of alkyl triepoxy carboxylate is C 12 H 25 -(OCH2CH2)3-OCH2COONa, and the structural formula of alkyl pentaepoxy carboxylate is C 12 H 25 -(OCH2CH2)5-OCH2COONa.

[0010] The second technical solution adopted by the present invention is that the preparation method of the compound scale and corrosion inhibitor of alkyl epoxy carboxylate is specifically implemented according to the following steps:

[0011] Step 1: Weigh fatty alcohol polyoxyethylene ether A and sodium chloroacetate, dissolve fatty alcohol polyoxyethylene ether A and sodium chloroacetate in absolute ethanol to obtain a mixed solution of fatty alcohol polyoxyethylene ether A and sodium chloroacetate, and add sodium hydroxide to the mixed solution of fatty alcohol polyoxyethylene ether A and sodium chloroacetate in three portions, stir and mix evenly for reaction to obtain alkyl triepoxy carboxylate;

[0012] Step 2: Weigh fatty alcohol polyoxyethylene ether B and sodium chloroacetate, dissolve fatty alcohol polyoxyethylene ether B and sodium chloroacetate in absolute ethanol to obtain a mixed solution of fatty alcohol polyoxyethylene ether B and sodium chloroacetate, and add sodium hydroxide to the mixed solution of fatty alcohol polyoxyethylene ether B and sodium chloroacetate in three portions, stir and mix evenly for reaction to obtain alkyl pentaepoxy carboxylate;

[0013] Step 3: Add the alkyl triepoxy carboxylate obtained in the above step 1 and the alkyl pentaepoxy carboxylate obtained in the above step 2 to absolute ethanol and mix evenly to obtain the compound scale and corrosion inhibitor of alkyl epoxy carboxylate.

[0014] The characteristics of the second technical solution of the present invention also lie in that

[0015] The specific steps of Step 1 are as follows:

[0016] Step 101: Dissolve fatty alcohol polyoxyethylene ether A and sodium chloroacetate in a container containing absolute ethanol and stir. The reaction temperature is 40 - 50°C, and the stirring time is 0.5 - 1 h. Add sodium hydroxide to the reaction solution of fatty alcohol polyoxyethylene ether A and sodium chloroacetate in three portions. The first portion is 50% of the total amount of sodium hydroxide, the second portion is 30% of the total amount of sodium hydroxide, and the third portion is 20% of the total amount of sodium hydroxide. Control the reaction temperature at 45 - 50°C, and the reaction time is 3 - 4 h. Then raise the temperature to 55°C and react for 0.5 - 1.0 h to obtain a crude product of alkyl triepoxy carboxylate.

[0017] Step 102: Use absolute ethanol as a diluent for the crude product of alkyl triepoxy carboxylate obtained in Step 101. The reaction temperature is 45 - 55°C, and the reaction time is 1 - 2 h. Cool the reaction mixture solution in an ice-water bath, filter, and distill to obtain alkyl triepoxy carboxylate.

[0018] In Step 101, the structural formula of fatty alcohol polyoxyethylene ether A is: C 12 H 25 -(OCH2CH2)3-OH. The molar ratio of fatty alcohol polyoxyethylene ether A to sodium chloroacetate in Step 101 is 1:1.0 - 1.5. The mass ratio of fatty alcohol polyoxyethylene ether A to absolute ethanol in Step 101 is 1:1.0 - 1.5. The molar ratio of fatty alcohol polyoxyethylene ether carboxylate A to sodium hydroxide in Step 101 is 1:1.0 - 1.3. The mass ratio of the crude product of alkyl triepoxy carboxylate to absolute ethanol in Step 102 is 1:1.0 - 1.5.

[0019] The specific steps of Step 2 are as follows:

[0020] Step 201: Dissolve fatty alcohol polyoxyethylene ether B and sodium chloroacetate in a container containing absolute ethanol. The reaction temperature is 40 - 50°C, and the stirring time is 0.5 - 1 h. Add sodium hydroxide to the reaction solution of fatty alcohol polyoxyethylene ether B and sodium chloroacetate in three portions. The first portion is 50% of the total amount of sodium hydroxide, the second portion is 30% of the total amount of sodium hydroxide, and the third portion is 20% of the total amount of sodium hydroxide. Control the reaction temperature at 45 - 50°C, and the reaction time is 3 - 4 h. Then raise the temperature to 55°C and react for 0.5 - 1.0 h to obtain a crude product of alkyl pentaepoxy carboxylate.

[0021] Step 202: Use absolute ethanol as a diluent for the crude product of alkyl pentaepoxy carboxylate obtained in Step 201. The reaction temperature is 45 - 55°C, and the reaction time is 1 - 2 h. Cool the reaction mixture solution in an ice-water bath, filter, and distill to obtain alkyl pentaepoxy carboxylate.

[0022] In Step 201, the structural formula of fatty alcohol polyoxyethylene ether B is: C 12 H 25 -(OCH2CH2)5-OH. In Step 201, the molar ratio of fatty alcohol polyoxyethylene ether B to sodium chloroacetate is 1:1.0 - 1.5. In Step 201, the mass ratio of fatty alcohol polyoxyethylene ether B to absolute ethanol is 1:1.0 - 1.5. In Step 201, the molar ratio of fatty alcohol polyoxyethylene ether B to sodium hydroxide is 1:1.0 - 1.3. In Step 202, the mass ratio of the crude alkyl triepoxy carboxylate synthesis product to absolute ethanol is 1:1.0 - 1.5.

[0023] The specific steps of Step 3 are as follows:

[0024] Step 301: Weigh 80% - 90% of alkyl triepoxy carboxylate and 10% - 20% of alkyl pentaepoxy carboxylate respectively by mass percentage, add absolute ethanol for dilution, add them to a container and stir. The reaction temperature is 50 - 55°C, and the reaction time is 1.5 - 2 h to obtain a crude alkyl epoxy carboxylate compound scale and corrosion inhibitor.

[0025] Step 302: Cool the crude alkyl epoxy carboxylate compound scale and corrosion inhibitor obtained in Step 301 in an ice-cooled water bath, filter, and distill to obtain an alkyl epoxy carboxylate compound scale and corrosion inhibitor.

[0026] In Step 301, the mass ratio of the mixture of alkyl triepoxy carboxylate and alkyl pentaepoxy carboxylate to absolute ethanol is 1:1.0 - 1.5.

[0027] The third technical solution adopted in the present invention is the application of the above-mentioned alkyl epoxy carboxylate compound scale and corrosion inhibitor in treating the mixed calcium scale in a cooling water system.

[0028] The beneficial effects of the present invention are as follows:

[0029] The alkyl epoxy carboxylate compound scale and corrosion inhibitor of the present invention not only has good dispersibility in water under the condition of low addition amount, makes the crystal growth of crystalline calcium scale distorted and deformed, inhibits the crystal growth rate, slows down the precipitation of calcium scale, but also undergoes a chemical complex reaction to form a film or reduces the electrochemical corrosion effect to form a corrosion inhibition effect on the surface of carbon steel. The alkyl epoxy carboxylate compound scale and corrosion inhibitor of the present invention is environmentally friendly, biodegradable, has excellent scale and corrosion inhibition performance for mixed calcium scale systems such as calcium carbonate, calcium sulfate, and calcium phosphate, can be used for various metal and non-metal material products, and is suitable for water circulation systems with local high temperatures such as urban geothermal heating systems, pipelines, and oil well production equipment. The preparation method of the alkyl epoxy carboxylate compound scale and corrosion inhibitor of the present invention has a simple process, low manufacturing cost, and strong practicability. Description of the Drawings

[0030] Figure 1 Infrared spectrum characterization spectra of characteristic functional groups of PAEC-3, PAEC-5 and PAEC35 prepared in Example 1 of the present invention;

[0031] Figure 2 Scale inhibition efficiency diagram of different PAEC35 concentrations on calcium carbonate scale prepared in Example 1 of the present invention;

[0032] Figure 3 Scale inhibition efficiency diagram of PAEC35 prepared in Example 1 of the present invention on calcium carbonate scale with different concentrations;

[0033] Figure 4 Scale inhibition efficiency diagram of different PAEC35 concentrations on calcium sulfate scale prepared in Example 1 of the present invention;

[0034] Figure 5 Scale inhibition efficiency diagram of different PAEC35 concentrations on calcium phosphate scale prepared in Example 1 of the present invention;

[0035] Figure 6 Corrosion inhibition efficiency diagram of different PAEC35 concentrations on carbon steel prepared in Example 1 of the present invention. Detailed implementation mode

[0036] The present invention will be described in detail below with reference to the accompanying drawings and specific implementation modes.

[0037] The alkyl epoxy carboxylate compound scale and corrosion inhibitor of the present invention is composed of the following raw material components by mass percentage:

[0038] Alkyl triepoxy carboxylate (PAEC-3) 80-90%, alkyl pentaepoxy carboxylate (PAEC-5) 10-20%, and the sum of the mass percentages of the above components is 100%; the number average molecular weight of the alkyl triepoxy carboxylate is 350-400 g / mol, and the number average molecular weight of the alkyl pentaepoxy carboxylate is 450-500 g / mol.

[0039] Functions of each component of the alkyl epoxy carboxylate compound scale and corrosion inhibitor of the present invention:

[0040] Alkyl triepoxy carboxylate (PAEC-3): mainly plays the role of dispersion and scale inhibition. The smaller the number of -(OCH2CH2)n- epoxy groups, the stronger the dispersion and scale inhibition effect. As the number of epoxy groups increases, the scale inhibition effect becomes worse, but the slow release effect is enhanced.

[0041] Alkyl pentaepoxy carboxylate (PAEC-5): mainly plays the role of slow release. The larger the number of -(OCH2CH2)n- epoxy groups, the better the slow release effect.

[0042] The basis or function for selecting the content of the alkyl epoxy carboxylate compound scale and corrosion inhibitor of the present invention is as follows:

[0043] 80 - 90% of alkyl triepoxy carboxylate (PAEC-3): Based on the efficiency of inhibiting calcium carbonate scale, the smaller the number of epoxy groups, the better the dispersion and scale inhibition effect. The scale inhibition efficiency of the ratio of alkyl triepoxy carboxylate to alkyl pentaepoxy carboxylate being 1:1, 2:1, 3:1, 4:1, and 5:1 was investigated, and the scale inhibition rates were 68.3%, 80.1%, 88.5%, 98.2%, and 96.8% respectively.

[0044] 10 - 20% of alkyl pentaepoxy carboxylate (PAEC-5): Adding a small amount of PAEC-5 can enhance the slow-release effect of the compound scale inhibitor, dispersant, and corrosion inhibitor of alkyl epoxy carboxylate.

[0045] The preparation method of the compound scale inhibitor, dispersant, and corrosion inhibitor of alkyl epoxy carboxylate in the present invention is as follows:

[0046] Step 1: Prepare alkyl triepoxy carboxylate (PAEC-3)

[0047] Specifically: Dissolve fatty alcohol polyoxyethylene ether A (C 12 H 25 -(OCH2CH2)3-OH) and sodium chloroacetate in a container with a certain amount of absolute ethanol, then keep the reaction temperature at 40 - 50 °C and stir and dissolve for 0.5 - 1 h. Then slowly add sodium hydroxide in three portions. Add 50% of the total amount of sodium hydroxide 0.5 h before the reaction time, add 30% of the total amount of sodium hydroxide at 0.5 - 0.75 h of the reaction time, and add 20% of the total amount of sodium hydroxide at 0.75 - 1 h of the reaction time. Finally, control the reaction temperature at 45 - 50 °C, react for 3 - 4 h, then raise the temperature to 55 °C, and end the reaction after 0.5 - 1.0 h to obtain the crude product of alkyl triepoxy carboxylate synthesis; Use absolute ethanol as a diluent for the crude product of alkyl triepoxy carboxylate synthesis, cool the reaction mixture solution in an ice-water bath for 24 h, filter, and distill to obtain the product alkyl triepoxy carboxylate.

[0048] Among them, the molar ratio of fatty alcohol polyoxyethylene ether A to sodium chloroacetate is 1:1.0 - 1.5, the mass ratio of fatty alcohol polyoxyethylene ether A to absolute ethanol is 1:1.0 - 1.5, the molar ratio of fatty alcohol polyoxyethylene ether A to sodium hydroxide is 1:1.0 - 1.3, and the mass ratio of the crude product of alkyl triepoxy carboxylate synthesis to absolute ethanol is 1:1.0 - 1.5.

[0049] Step 2: Prepare alkyl pentaepoxy carboxylate (PAEC-5)

[0050] Specifically: Dissolve fatty alcohol polyoxyethylene ether B (C 12 H 25-(OCH2CH2)5-OH) and sodium chloroacetate are dissolved in a container with a certain amount of absolute ethanol. Then, the reaction temperature is maintained at 40 - 50 °C for 0.5 - 1 h of stirring and dissolution. Next, sodium hydroxide is slowly added in three portions. 50% of the total amount of sodium hydroxide is added 0.5 h before the reaction time, 30% of the total amount of sodium hydroxide is added during 0.5 - 0.75 h of the reaction time, and 20% of the total amount of sodium hydroxide is added during 0.75 - 1 h of the reaction time. Finally, the reaction temperature is controlled at 45 - 50 °C for 3 - 4 h, and then the temperature is raised to 55 °C. After reacting for 0.5 - 1.0 h, the reaction ends to obtain a crude product of alkyl pentaepoxy carboxylate; the crude product of alkyl pentaepoxy carboxylate uses absolute ethanol as a diluent, and the reaction mixture solution is cooled in an ice-water bath for 24 h, filtered, and distilled to obtain the product alkyl pentaepoxy carboxylate.

[0051] Among them, the molar ratio of fatty alcohol polyoxyethylene ether B to sodium chloroacetate is 1:1.0 - 1.5, the mass ratio of fatty alcohol polyoxyethylene ether B to absolute ethanol is 1:1.0 - 1.5, the molar ratio of fatty alcohol polyoxyethylene ether B to sodium hydroxide is 1:1.0 - 1.3, and the mass ratio of the crude product of alkyl pentaepoxy carboxylate to absolute ethanol is 1:1.0 - 1.5.

[0052] Step 3: Prepare a compound scale and corrosion inhibitor of alkyl epoxy carboxylate (PAEC35)

[0053] The specific steps are as follows: Under the condition of using absolute ethanol as a diluent, 80% - 90% of alkyl triepoxy carboxylate and 10% - 20% of alkyl pentaepoxy carboxylate are added to the reaction container according to mass percentage. The reaction temperature is controlled at 50 - 55 °C, and the reaction time is 1.5 - 2 h. Stir to make it fully dissolve to obtain a crude product of the compound scale and corrosion inhibitor of alkyl epoxy carboxylate; the crude product of the compound scale and corrosion inhibitor of alkyl epoxy carboxylate is cooled in an ice-water bath, filtered, and distilled to obtain the product compound scale and corrosion inhibitor of alkyl epoxy carboxylate (PAEC35).

[0054] The functions of each step in the preparation method of the compound scale and corrosion inhibitor of alkyl epoxy carboxylate of the present invention:

[0055] Adding the alkaline activator sodium hydroxide to the reaction substrates fatty alcohol polyoxyethylene ether and sodium chloroacetate activates and detaches the -OH in the fatty alcohol polyoxyethylene ether, and a grafting reaction occurs with sodium chloroacetate to obtain alkyl epoxy carboxylate and HCl.

[0056] Application of the compound scale and corrosion inhibitor of alkyl epoxy carboxylate of the present invention in the process of treating mixed calcium scale in a cooling water system.

[0057] Example 1

[0058] The preparation method of the alkyl epoxy carboxylate compound scale and corrosion inhibitor in this embodiment is carried out by the following steps:

[0059] Step 1: Add 40 g of paste-like fatty alcohol polyoxyethylene ether A (C 12 H 25 -(OCH2CH2)3-OH) and 51 mL of absolute ethanol into a 500 mL three-necked flask equipped with a condensing device, and then stir magnetically. Control the water bath temperature at 40 °C, and the heating duration is 0.5 h. Stir to completely dissolve the fatty alcohol polyoxyethylene ether A. Add 15 g of sodium chloroacetate, and uniformly add the sodium chloroacetate powder into the homogeneous fatty alcohol polyoxyethylene ether A solution obtained above. Then add 6 g of sodium hydroxide in three portions. Add 3 g of sodium hydroxide 0.5 h before the reaction time, add 1.8 g of sodium hydroxide at the 0.5 - 0.75 h of the reaction time, and add 1.2 g of sodium hydroxide at the 0.75 - 1 h of the reaction time. The water bath temperature is 45 °C, and the heating time is 3.0 h. Then raise the temperature to 55 °C, and the reaction time is 0.5 h, so that the fatty alcohol polyoxyethylene ether A (C 12 H 25 -(OCH2CH2)3-OH) and sodium chloroacetate react fully through the strong base activation of sodium hydroxide on the hydroxyl group (-OH) to obtain a crude product of alkyl triepoxy carboxylate (PAEC-3). Add 65 ml of absolute ethanol, the water bath temperature is 45 °C, and the reaction time is 1.0 h. After the experiment, cool and let the reaction mixture stand in an ice-water bath for 24 h, filter, and distill to finally obtain the product alkyl triepoxy carboxylate (PAEC-3).

[0060] Step 2: Add 40 g of paste-like fatty alcohol polyoxyethylene ether B (C 12 H 25 -(OCH2CH2)5-OH) and 51 mL of absolute ethanol into a 500 mL three-necked flask equipped with a condensing device, and then stir magnetically. Control the water bath temperature at 40 °C, and the heating duration is 0.5 h. Stir to completely dissolve the fatty alcohol polyoxyethylene ether B. Add 13 g of sodium chloroacetate, and uniformly add the sodium chloroacetate powder into the homogeneous fatty alcohol polyoxyethylene ether B solution obtained above. Then add 5 g of sodium hydroxide in three portions. Add 2.5 g of sodium hydroxide 0.5 h before the reaction time, add 1.5 g of sodium hydroxide at the 0.5 - 0.75 h of the reaction time, and add 1.0 g of sodium hydroxide at the 0.75 - 1 h of the reaction time. The water bath temperature is 45 °C, and the heating time is 3.0 h. Then raise the temperature to 55 °C, and the reaction time is 0.5 h, so that the fatty alcohol polyoxyethylene ether B (C 12 H 25-(OCH2CH2)5-OH) and sodium chloroacetate react fully by activating the hydroxyl group (-OH) with strong base sodium hydroxide to obtain the crude product of alkyl pentaepoxy carboxylate (PAEC-5). Add 63 ml of absolute ethanol, keep the water bath temperature at 45 °C, and the reaction time is 1.0 h. After the experiment, cool the reaction mixture solution in an ice-water bath and let it stand for 24 h, then filter and distill to finally obtain the product alkyl pentaepoxy carboxylate (PAEC-5).

[0061] Step 3: Prepare the compound scale and corrosion inhibitor of alkyl epoxy carboxylate (PAEC35). Add 40 ml of absolute ethanol as a diluent to a 500 mL three-necked flask equipped with a condensing device. Add 24 g of alkyl triepoxy carboxylate and 6 g of alkyl pentaepoxy carboxylate to the three-necked flask, control the reaction temperature at 50 °C, and stir to dissolve them fully to obtain the crude product of the compound scale and corrosion inhibitor of alkyl epoxy carboxylate. Cool the crude product of the compound scale and corrosion inhibitor of alkyl epoxy carboxylate in an ice-cooled water bath for 24 h, filter, and distill to obtain the product of the compound scale inhibitor and corrosion inhibitor of alkyl epoxy carboxylate (PAEC35). The synthesis conversion yield of PAEC35 is 98.8%, the purity of the product > 95%, and it is a yellow viscous liquid.

[0062] The infrared spectra of the characteristic functional groups in PAEC-3, PAEC-5, and PAEC35 are shown in Figure 1 . From Figure 1 the results, it can be seen that the products of PAEC-3, PAEC-5, and PAEC35 show stretching vibration peaks of C-H at 3150 cm -1 , 2855 - 2822 cm -1 , indicating the presence of alkyl groups in the compound; at 1114 - 1107 cm -1 are the characteristic absorption peaks of the epoxy group (C=O=C), proving the effective synthesis of the epoxy group in the product; at 890 - 842 cm -1 appears an asymmetric stretching vibration peak of C=O, indicating the presence of an out-of-plane deformation vibration peak of the carboxyl group. At 1650 cm -1 and 1560 cm -1 appear the carbonyl coupling effect and the stretching vibration peak of the carbon-oxygen double bond of -COOH respectively, indicating that the fatty alcohol polyoxyethylene ether, the PAEC synthesis precursor, undergoes a carboxymethylation reaction with sodium chloroacetate, and its absorption vibration peaks show the presence of carboxylate. Based on the appearance of the functional group peaks in the above PAEC products, the accuracy of the synthesized PAEC compounds in the experiment is proved.

[0063] The scale inhibition and dispersion corrosion inhibitor compounded with alkyl epoxy carboxylate of the present invention is used to test the scale inhibition performance of calcium carbonate according to the method of "Determination of scale inhibition performance of water treatment agents - Calcium carbonate deposition method" in "GB / T 16632 - 2008". Application experiment 1: Prepare the experimental water sample with anhydrous calcium chloride and sodium bicarbonate in a 250 mL volumetric flask. In the water sample, 2+ [Ca - = [HCO3 Figure 2 = 250 mg / L (calculated as CaCO3). Take 8 250 mL round-bottom flasks and label them from 1 to 8. Add 250 mL of the experimentally prepared water sample to the No. 1 flask as the blank control group. Add the alkyl epoxy carboxylate compound scale inhibitor and corrosion inhibitor (PAEC35) to the flasks No. 2 - 8 in sequence with concentrations of 10 mg / L, 20 mg / L, 30 mg / L, 40 mg / L, 50 mg / L, 60 mg / L, and 70 mg / L. Put the test water sample in and gradually heat it to 80 °C, keep it at a constant temperature for 10 h, and use the ethylenediaminetetraacetic acid (EDTA) complexometric titration method to measure the calcium ion concentration and calculate the scale inhibition rate. The measured results are as 2 + [Ca - = [HCO3 Figure 3 = 250 mg / L (calculated as CaCO3). Take 5 250 mL round-bottom flasks and label them from 1 to 5. Add 250 mL of the experimentally prepared water sample to the No. 1 flask as the blank control group. First, add 30 mg / L of the alkyl epoxy carboxylate compound scale inhibitor and corrosion inhibitor (PAEC35) to the flasks No. 2 - 5, and then add CaCO3 with concentrations of 250 mg / L, 500 mg / L, 750 mg / L, and 1000 mg / L in sequence. Put the test water sample in and gradually heat it to 80 °C, keep it at a constant temperature for 10 h, and use the ethylenediaminetetraacetic acid (EDTA) complexometric titration method to measure the calcium ion concentration and calculate the scale inhibition rate. The measured results are as

[0064] The scale inhibition and dispersion corrosion inhibition performance test of calcium sulfate scale was carried out by using the alkyl epoxy carboxylate compound scale inhibitor of the present invention according to the "GB / T 16632-2008 Determination of Scale Inhibition Performance of Water Treatment Agents - Calcium Carbonate Deposition Method". In a 250 mL volumetric flask, the experimental water sample was prepared with sodium sulfate and anhydrous calcium chloride. In the water sample, [Ca 2+ = 7200 mg / L (calculated as CaSO4), [SO4 2- = 6800 mg / L (calculated as Na2SO4). Take 8 250 ml round-bottom flasks and label them from 1 to 8. Add 250 mL of the experimental water sample prepared in the 1st flask as the blank control group. In the 2nd to 8th flasks, add the alkyl epoxy carboxylate compound scale inhibitor and corrosion inhibitor dispersant (PAEC35) with concentrations of 10 mg / L, 20 mg / L, 30 mg / L, 40 mg / L, 50 mg / L, 60 mg / L, and 70 mg / L in sequence. The test water sample was placed in a constant temperature water bath at 70 °C without concentration for 6 h. The calcium ion concentration was determined by ethylenediaminetetraacetic acid complexometric titration method and the scale inhibition rate was calculated. The measurement results are as Figure 4 shown. As the addition amount of the PAEC35 compound increases, the scale inhibition efficiency gradually increases. When the addition amount is 40 mg / L, the scale inhibition efficiency reaches the highest value, and the scale inhibition efficiency of calcium sulfate scale is 93.1%, indicating that PAEC35 has a good effect on inhibiting calcium sulfate scale at a low addition amount.

[0065] The scale inhibition performance test of calcium phosphate scale was carried out by using the alkyl epoxy carboxylate compound scale inhibitor of the present invention according to the "GB / T 16632-2008 Determination of Scale Inhibition Performance of Water Treatment Agents - Calcium Carbonate Deposition Method". In a 250 mL volumetric flask, the experimental water sample was prepared with dipotassium hydrogen phosphate and anhydrous calcium chloride. In the water sample, [Ca 2+ = 250 mg / L (calculated as CaCO3), [PO4 3- = 5 mg / L (calculated as PO4 3- ), and the pH was adjusted to 9 with sodium borate. Take 8 250 mL round-bottom flasks and label them from 1 to 8. Add 250 ml of the experimental water sample prepared in the 1st flask as the blank control group. In the 2nd to 8th flasks, add the alkyl epoxy carboxylate compound scale inhibitor and corrosion inhibitor dispersant (PAEC35) with concentrations of 10 mg / L, 20 mg / L, 30 mg / L, 40 mg / L, 50 mg / L, 60 mg / L, and 70 mg / L in sequence. The test water sample was kept at a constant temperature of 80 °C in a water bath for 10 h. After the test water sample was kept at a constant temperature of 80 °C in a water bath for 10 h and the solution was allowed to stand and cool to room temperature, the supernatant was taken with a dropper and filtered with filter paper. The PO4 3- in the obtained filtrate was colored for 15 min with ascorbic acid and ammonium molybdate. After the color reaction was complete, the absorbance of the solution was measured with a spectrophotometer (wavelength 710 nm), and compared with the fitted PO4 3-Compare the concentration standard curves and calculate the scale inhibition efficiency of PAEC35 on calcium phosphate scale. The measured results are as Figure 5 shown. When the dosage of PAEC35 is 10 - 45 mg / L, the scale inhibition efficiency increases with the increase of concentration, then decreases slightly, and then remains constant. When the concentration of PAEC35 is about 42 mg / L, the maximum scale inhibition efficiency is reached, and the scale inhibition rate is 81.5%.

[0066] The rotary coupon method was used to test the corrosion inhibition performance of the alkyl epoxy carboxylate compound scale and corrosion inhibitor (PAEC35) of the present invention on carbon steel according to the method of "GB / T 18175 - 2000 Determination of Corrosion Inhibition Performance of Water Treatment Agents". In a 250 mL volumetric flask, experimental water samples were prepared with anhydrous calcium chloride, magnesium sulfate heptahydrate, sodium chloride, and sodium bicarbonate. In the water sample, [Ca 2+ = 265 mg / L, [Mg 2+ = 47 mg / L, [HCO3 - )] = 122 mg / L. The A20 carbon steel specimens need to be pretreated before the experiment. First, wipe the carbon steel with sandpaper, and then scrub it successively with n - hexane and anhydrous ethanol to remove the oil on the surface of the steel sheet, and dry it for standby. Take 11 pre - prepared A20 standard test carbon steel coupons for corrosion inhibition experiments and label them from 1 to 11; take 11 1000 mL beakers and label them from 1 to 11. Add 500 ml of the experimental water sample prepared in the 1st beaker as the blank control group. In the 2nd - 8th beakers, first add 500 mL of the experimental water sample, and then successively add the alkyl epoxy carboxylate compound scale and corrosion inhibitor (PAEC35) at concentrations of 10 mg / L, 20 mg / L, 30 mg / L, 40 mg / L, 50 mg / L, 60 mg / L, 70 mg / L, 80 mg / L, 90 mg / L, and 100 mg / L. Use an RCC - Ⅲ type rotary coupon corrosion monitor to measure the corrosion inhibition efficiency of PAEC35. The rotation rate is 80 r / min, the water sample test temperature is 80 °C, and the reaction time is 10 h. After the experiment, use the coupon mass loss method to calculate the corrosion inhibition efficiency of PAEC35 on the carbon steel sheet. The measured results are as Figure 6 shown. When the dosage concentration of PAEC35 < 30 mg / L, the corrosion inhibition efficiency is negative, indicating that low - concentration PAEC has little corrosion inhibition effect on carbon steel; as the concentration of PAEC35 increases, the corrosion inhibition rate gradually increases. When the concentration of PAEC35 is 30 mg / L, the corrosion inhibition efficiency is 0, indicating the effect of the critical threshold at this concentration; when the dosage concentration is 30 mg / L - 100 mg / L, the corrosion inhibition efficiency of PAEC35 reaches the highest value of 35.5%.

[0067] Example 2

[0068] The preparation method of the alkyl epoxy carboxylate compound scale and corrosion inhibitor in this embodiment comprises the following steps:

[0069] Step 1: Add 45 g of paste-like fatty alcohol polyoxyethylene ether A (C 12 H 25 -(OCH2CH2)3-OH) and 75 mL of absolute ethanol into a 500 mL three-necked flask equipped with a condensing device, and then stir magnetically. Control the water bath temperature at 45 °C, and the heating duration is 0.75 h. Stir to completely dissolve the fatty alcohol polyoxyethylene ether A; add 21 g of sodium chloroacetate, and uniformly add the sodium chloroacetate powder into the homogeneous fatty alcohol polyoxyethylene ether A solution obtained above. Then add 7 g of sodium hydroxide in three portions. Add 3.5 g of sodium hydroxide 0.5 h before the reaction time, add 2.1 g of sodium hydroxide at 0.5 - 0.75 h of the reaction time, and add 1.4 g of sodium hydroxide at 0.75 - 1 h of the reaction time. The water bath temperature is 47.5 °C, and the heating time is 3.5 h. Raise the temperature to 55 °C and react for 0.75 h to make the fatty alcohol polyoxyethylene ether A (C 12 H 25 -(OCH2CH2)3-OH) and sodium chloroacetate react fully through the strong base activation of sodium hydroxide on the hydroxyl group (-OH) to obtain a crude product of alkyl triepoxy carboxylate (PAEC-3). Add 90 ml of absolute ethanol, the water bath temperature is 50 °C, and the reaction time is 1.5 h. After the experiment, cool and let the reaction mixture stand in an ice-water bath for 24 h, filter, and distill to finally obtain the product alkyl triepoxy carboxylate.

[0070] Step 2: Add 45 g of paste-like fatty alcohol polyoxyethylene ether B (C 12 H 25 -(OCH2CH2)5-OH) and 70 mL of absolute ethanol into a 500 mL three-necked flask equipped with a condensing device, and then stir magnetically. Control the water bath temperature at 45 °C, and the heating duration is 0.75 h. Stir to completely dissolve the fatty alcohol polyoxyethylene ether B; add 18 g of sodium chloroacetate, and uniformly add the sodium chloroacetate powder into the homogeneous fatty alcohol polyoxyethylene ether B solution obtained above. Then add 6 g of sodium hydroxide in three portions. Add 3 g of sodium hydroxide 0.5 h before the reaction time, add 1.8 g of sodium hydroxide at 0.5 - 0.75 h of the reaction time, and add 1.2 g of sodium hydroxide at 0.75 - 1 h of the reaction time. The water bath temperature is 47.5 °C, and the heating time is 3.5 h. Raise the temperature to 55 °C and react for 0.75 h to make the fatty alcohol polyoxyethylene ether B (C 12 H 25-(OCH2CH2)5-OH) and sodium chloroacetate react fully through strong alkali activation of the hydroxyl group (-OH) by sodium hydroxide to obtain a crude product of alkyl pentaepoxy carboxylate (PAEC-3). Add 88 ml of absolute ethanol, keep the water bath temperature at 50 °C, and the reaction time is 1.5 h. After the experiment, cool and let the reaction mixture stand in an ice-water bath for 24 h, filter, and distill to finally obtain the product alkyl pentaepoxy carboxylate.

[0071] Step 3: Prepare a compound scale and corrosion inhibitor of alkyl epoxy carboxylate (PAEC35). Add 48 ml of absolute ethanol as a diluent to a 500 mL three-necked flask equipped with a condensing device. Add 25.5 g of alkyl triepoxy carboxylate and 4.5 g of alkyl pentaepoxy carboxylate to the three-necked flask, control the reaction temperature at 50 °C, and stir to dissolve them fully to obtain a crude product of the compound scale and corrosion inhibitor of alkyl epoxy carboxylate. Cool the crude product of the compound scale and corrosion inhibitor of alkyl epoxy carboxylate in an ice-water bath for 24 h, filter, and distill to obtain the product of the compound scale and corrosion inhibitor of alkyl epoxy carboxylate (PAEC35). The synthesis conversion yield of PAEC35 is 98.8%, the purity of the product > 95%, and it is a yellow viscous liquid.

[0072] Example 3

[0073] The preparation method of the compound scale and corrosion inhibitor of alkyl epoxy carboxylate in this example adopts the following steps:

[0074] Step 1: Add 50 g of paste-like fatty alcohol polyoxyethylene ether A (C 12 H 25 -(OCH2CH2)3-OH) and 95 mL of absolute ethanol, then stir magnetically, control the water bath temperature at 50 °C, and the heating duration is 1.0 h. Stir to completely dissolve the fatty alcohol polyoxyethylene ether A; add 27 g of sodium chloroacetate, and evenly add the sodium chloroacetate powder to the homogeneous fatty alcohol polyoxyethylene ether A solution obtained above. Then add 8 g of sodium hydroxide in three portions. Add 4 g of sodium hydroxide 0.5 h before the reaction time, add 2.4 g of sodium hydroxide at 0.5 - 0.75 h of the reaction time, and add 1.6 g of sodium hydroxide at 0.75 - 1.0 h of the reaction time. Keep the water bath temperature at 50 °C, the heating time is 4 h, raise the temperature to 55 °C, and react for 1.0 h to make the fatty alcohol polyoxyethylene ether A (C 12 H 25-(OCH2CH2)3-OH) and sodium chloroacetate react fully through strong alkali activation of the hydroxyl group (-OH) by sodium hydroxide to obtain a crude product of alkyl triepoxy carboxylate (PAEC-3). Add 120 ml of absolute ethanol, keep the water bath temperature at 55 °C, and the reaction time is 2.0 h. After the experiment, cool and let stand the reaction mixture solution in an ice-water bath for 24 h, filter, and distill to finally obtain the product alkyl triepoxy carboxylate.

[0075] Step 2: Add 50 g of the paste-like fatty alcohol polyoxyethylene ether B (C 12 H 25 -(OCH2CH2)5-OH) and 95 ml of absolute ethanol into a 500 mL three-necked flask equipped with a condensing device, and then stir magnetically. Control the water bath temperature at 50 °C and the heating duration at 1.0 h to completely dissolve the fatty alcohol polyoxyethylene ether B by stirring; add 22 g of sodium chloroacetate, and evenly add the sodium chloroacetate powder into the homogeneous fatty alcohol polyoxyethylene ether B solution obtained above. Then add 6.8 g of sodium hydroxide in three portions. Add 3.4 g of sodium hydroxide at the reaction time of 0.5 h, add 2.04 g of sodium hydroxide at the reaction time of 0.5 - 0.75 h, and add 1.36 g of sodium hydroxide at the reaction time of 0.75 - 1.0 h. Keep the water bath temperature at 50 °C and the heating time at 4 h, then raise the temperature to 55 °C and react for 1.0 h to make the fatty alcohol polyoxyethylene ether B (C 12 H 25 -(OCH2CH2)5-OH) and sodium chloroacetate react fully through strong alkali activation of the hydroxyl group (-OH) by sodium hydroxide to obtain a crude product of alkyl pentaepoxy carboxylate (PAEC-5). Add 116 ml of absolute ethanol, keep the water bath temperature at 55 °C, and the reaction time is 2.0 h. After the experiment, cool and let stand the reaction mixture solution in an ice-water bath for 24 h, filter, and distill to finally obtain the product alkyl pentaepoxy carboxylate.

[0076] Step 3: Prepare a compound scale and corrosion inhibitor of alkyl epoxy carboxylate (PAEC35). Add 57 ml of absolute ethanol as a diluent into a 500 mL three-necked flask equipped with a condensing device. Add 27 g of alkyl triepoxy carboxylate and 3 g of alkyl pentaepoxy carboxylate into the three-necked flask, control the reaction temperature at 50 °C, and stir to dissolve them fully to obtain a crude product of the compound scale and corrosion inhibitor of alkyl epoxy carboxylate. Cool the crude product of the compound scale and corrosion inhibitor of alkyl epoxy carboxylate in an ice-water bath for 24 h, filter, and distill to obtain the product of the compound scale and corrosion inhibitor of alkyl epoxy carboxylate (PAEC35). The synthesis conversion yield of PAEC35 is 98.8%, the purity of the product > 95%, and it is a yellow viscous liquid.

[0077] Example 4

[0078] The preparation method of the alkyl epoxy carboxylate compound scale and corrosion inhibitor in this embodiment is carried out in the following steps:

[0079] Step 1: Add 50 g of paste-like fatty alcohol polyoxyethylene ether A (C 12 H 25 -(OCH2CH2)3-OH) and 85 mL of absolute ethanol into a 500 mL three-necked flask equipped with a condensing device, and then stir magnetically. Control the water bath temperature at 50 °C, and the heating duration is 1.0 h. Stir to completely dissolve the fatty alcohol polyoxyethylene ether A; add 25 g of sodium chloroacetate, and evenly add the sodium chloroacetate powder into the homogeneous fatty alcohol polyoxyethylene ether A solution obtained above. Then add 7.6 g of sodium hydroxide in three batches. Add 3.8 g of sodium hydroxide in the reaction time of 0 - 0.5 h, add 2.28 g of sodium hydroxide in the reaction time of 0.5 - 0.75 h, and add 1.52 g of sodium hydroxide in the reaction time of 0.75 - 1.0 h. The water bath temperature is 50 °C, and the heating time is 4 h. Then raise the temperature to 55 °C and react for 1.0 h to make the fatty alcohol polyoxyethylene ether A (C 12 H 25 -(OCH2CH2)3-OH) and sodium chloroacetate fully react through the strong base activation of sodium hydroxide on the hydroxyl group (-OH) to obtain a crude product of alkyl triepoxy carboxylate (PAEC-3). Add 108 ml of absolute ethanol, the water bath temperature is 55 °C, and the reaction time is 2.0 h. After the experiment, cool and let the reaction mixture stand in an ice-water bath for 24 h, filter, and distill to finally obtain the product alkyl triepoxy carboxylate.

[0080] Step 2: Add 50 g of paste-like fatty alcohol polyoxyethylene ether B (C 12 H 25 -(OCH2CH2)5-OH) and 85 mL of absolute ethanol into a 500 mL three-necked flask equipped with a condensing device, and then stir magnetically. Control the water bath temperature at 50 °C, and the heating duration is 1.0 h. Stir to completely dissolve the fatty alcohol polyoxyethylene ether B; add 20 g of sodium chloroacetate, and evenly add the sodium chloroacetate powder into the homogeneous fatty alcohol polyoxyethylene ether B solution obtained above. Then add 6 g of sodium hydroxide in three times. Add 3 g of sodium hydroxide in the first 0.5 h of the reaction time, add 1.8 g of sodium hydroxide in the reaction time of 0.5 - 0.75 h, and add 1.2 g of sodium hydroxide in the reaction time of 0.75 - 1.0 h. The water bath temperature is 50 °C, and the heating time is 4 h. Then raise the temperature to 55 °C and react for 1.0 h to make the fatty alcohol polyoxyethylene ether B (C 12 H 25-(OCH2CH2)5-OH) and sodium chloroacetate react fully through strong alkali activation of the hydroxyl group (-OH) by sodium hydroxide to obtain a crude product of alkyl pentaepoxy carboxylate (PAEC-5). Add 105 ml of absolute ethanol, keep the water bath temperature at 55 °C, and the reaction time is 2.0 h. After the experiment, cool the reaction mixture solution in an ice-water bath, let it stand for 24 h, filter, and distill to finally obtain the product alkyl pentaepoxy carboxylate.

[0081] Step 3: Prepare a compound scale and corrosion inhibitor of alkyl epoxy carboxylate (PAEC35). Add 52 ml of absolute ethanol as a diluent to a 500 mL three-necked flask equipped with a condensing device. Add 25.8 g of alkyl triepoxy carboxylate and 4.2 g of alkyl pentaepoxy carboxylate to the three-necked flask, control the reaction temperature at 50 °C, and stir to dissolve them fully to obtain a crude product of the compound scale and corrosion inhibitor of alkyl epoxy carboxylate. Cool the crude product of the compound scale and corrosion inhibitor of alkyl epoxy carboxylate in an ice-water bath for 24 h, filter, and distill to obtain the product of the compound scale inhibitor and corrosion inhibitor of alkyl epoxy carboxylate (PAEC35). The synthesis conversion yield of PAEC35 is 98.8%, the purity of the product > 95%, and it is a yellow viscous liquid.

Claims

1. Alkyl epoxy carboxylate compounded scale and dispersible corrosion inhibitor, characterized in that: The raw material components are as follows according to mass percentage: 80-90% alkyl triepoxy carboxylate, 10-20% alkyl pentaepoxy carboxylate, the sum of the mass percentages of the above components is 100%; the number average molecular weight of the alkyl triepoxy carboxylate is 350-400 g / mol, and the number average molecular weight of the alkyl pentaepoxy carboxylate is 450-500 g / mol; The structural formula of the alkyl triepoxy carboxylate is C 12 H 25 -(OCH2CH2)3-OCH2COONa, the structural formula of the alkyl pentacyclic oxygen carboxylate is C 12 H 25 -(OCH2CH2)5-OCH2COONa; The preparation method of the alkyl epoxy carboxylate compound scale inhibitor, dispersible corrosion inhibitor is specifically implemented according to the following steps: Step 1, weighing fatty alcohol polyoxyethylene ether A and sodium chloroacetate, dissolving fatty alcohol polyoxyethylene ether A and sodium chloroacetate in anhydrous ethanol to obtain a mixed solution of fatty alcohol polyoxyethylene ether A and sodium chloroacetate, adding sodium hydroxide to the mixed solution of fatty alcohol polyoxyethylene ether A and sodium chloroacetate three times, stirring and mixing to react, and obtaining an alkyl triepoxy carboxylate; Step 101, dissolving fatty alcohol polyoxyethylene ether A and sodium chloroacetate in a container containing anhydrous ethanol and stirring, the reaction temperature is 40-50° C., the stirring time is 0.5-1h, sodium hydroxide is added to the reaction solution of fatty alcohol polyoxyethylene ether A and sodium chloroacetate three times, 50% of the total amount of sodium hydroxide is added for the first time, 30% of the total amount of sodium hydroxide is added for the second time, and 20% of the total amount of sodium hydroxide is added for the third time, the reaction temperature is controlled at 45-50° C., the reaction time is 3-4h, and then the temperature is increased to 55° C., and the reaction is carried out for 0.5-1.0h to obtain a crude synthetic product of alkyl triepoxy carboxylate; Step 102, using anhydrous ethanol as a diluent to dilute the crude alkyl triepoxy carboxylate synthesis product obtained in step 101, at a reaction temperature of 45-55° C., for a reaction time of 1-2 h, cooling the reaction mixture in an ice-cooled water bath, filtering, and distilling to obtain an alkyl triepoxy carboxylate; The structural formula of the fatty alcohol polyoxyethylene ether A in step 101 is: 12 H 25 -(OCH2CH2)3-OH, the molar ratio of fatty alcohol polyoxyethylene ether A to sodium chloroacetate in step 101 is 1:1.0-1.5, the mass ratio of fatty alcohol polyoxyethylene ether A to anhydrous ethanol in step 101 is 1:1.0-1.5, the molar ratio of fatty alcohol polyoxyethylene ether A to sodium hydroxide in step 101 is 1:1.0-1.3, and the mass ratio of alkyl triepoxy carboxylate synthetic crude product to anhydrous ethanol in step 102 is 1:1.0-1.5; Step 2, weighing fatty alcohol polyoxyethylene ether B and sodium chloroacetate, dissolving fatty alcohol polyoxyethylene ether B and sodium chloroacetate in anhydrous ethanol to obtain a mixed solution of fatty alcohol polyoxyethylene ether B and sodium chloroacetate, adding sodium hydroxide to the mixed solution of fatty alcohol polyoxyethylene ether B and sodium chloroacetate three times, stirring and mixing to obtain alkyl pentacyclic epoxy carboxylate; Step 201, dissolving fatty alcohol polyoxyethylene ether B and sodium chloroacetate in a container containing anhydrous ethanol, the reaction temperature is 40-50° C., the stirring time is 0.5-1h, sodium hydroxide is added to the reaction solution of fatty alcohol polyoxyethylene ether B and sodium chloroacetate three times, 50% of the total amount of sodium hydroxide is added for the first time, 30% of the total amount of sodium hydroxide is added for the second time, and 20% of the total amount of sodium hydroxide is added for the third time, the reaction temperature is controlled at 45-50° C., the reaction time is 3-4h, then the temperature is increased to 55° C., and the reaction is carried out for 0.5-1.0h to obtain a crude synthetic product of alkyl pentacyclic epoxy carboxylate; Step 202, the crude synthetic product of alkyl pentacyclic epoxy carboxylate obtained in step 201 is treated with anhydrous ethanol as a diluent, the reaction temperature is 45-55° C., the reaction time is 1-2 hours, the reaction mixture is cooled in an ice water bath, filtered, and distilled to obtain alkyl pentacyclic epoxy carboxylate; The structural formula of the fatty alcohol polyoxyethylene ether B in step 201 is: 12 H 25 -(OCH2CH2)5-OH, the molar ratio of fatty alcohol polyoxyethylene ether B to sodium chloroacetate in step 201 is 1:1.0-1.5, the mass ratio of fatty alcohol polyoxyethylene ether B to anhydrous ethanol in step 201 is 1:1.0-1.5, the molar ratio of fatty alcohol polyoxyethylene ether B to sodium hydroxide in step 201 is 1:1.0-1.3, and the mass ratio of the synthetic crude product of alkyl pentacyclic carboxylate to anhydrous ethanol in step 202 is 1:1.0-1.5; Step 3, adding the alkyl triepoxy carboxylate obtained in the above step 1 and the alkyl pentaepoxy carboxylate obtained in the above step 2 into anhydrous ethanol and mixing them evenly to obtain an alkyl epoxy carboxylate composite scale inhibitor and dispersible corrosion inhibitor; Step 301, weigh 80%-90% of alkyl triepoxy carboxylate and 10%-20% of alkyl pentaepoxy carboxylate respectively according to mass percentage, add anhydrous ethanol to dilute, add to a container with stirring, react at a temperature of 50-55° C., and react for 1.5-2 h to obtain a crude product of alkyl epoxy carboxylate composite scale inhibitor and dispersant; In step 301, the mass ratio of the mixture of alkyl triepoxy carboxylates and alkyl pentaepoxy carboxylates to anhydrous ethanol is 1:1.0-1.5; Step 302: cool the crude product of the alkyl epoxy carboxylate compound scale inhibitor, dispersant and corrosion inhibitor obtained in step 301 in an ice-cooled water bath, filter and distill to obtain the alkyl epoxy carboxylate compound scale inhibitor, dispersant and corrosion inhibitor.

2. Use of the alkyl epoxy carboxylate compound scale inhibitor and dispersant according to claim 1 in treating mixed calcium scale in a cooling water system.

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