A polyamine-based boiler water treatment agent and its preparation method and use method

Abstract

The present invention relates to the technical field of film-forming descaling agents, and in particular to a boiler water treatment agent based on polyamines, a preparation method thereof, and a use method thereof. The raw materials for preparing the boiler water treatment agent include: polyamines and composite chelating agents, and the molar ratio is 1: (4-6). The boiler water treatment agent provided by the present invention has a wide applicable temperature and pressure range, can withstand extreme conditions of up to 600°C and 17.8MPa, has excellent film-forming performance, can form a denser and more stable protective film layer on the metal surface, and provides reliable anti-corrosion protection. The corrosion rate of carbon steel in boiler water is as low as 0.12g / (m 2 h).

Description

Technical Field

[0001] The invention relates to the technical field of film-forming descaling agents, and in particular to a polyamine-based boiler water treatment agent and a preparation method and a use method thereof. Background Art

[0002] Boiler water treatment agent is a chemical agent specially designed to improve the water quality inside the boiler, prevent scaling, corrosion and sediment accumulation. Its application is crucial to ensure the safe operation of the boiler system, improve thermal efficiency, reduce maintenance costs and extend equipment life. Boilers of different types and specifications will choose water treatment agents with different formulations according to their working pressure, water quality conditions, steam quality requirements and other factors. The performance of boiler water treatment agents in the prior art is significantly degraded under extreme temperature and pressure conditions, and they are prone to decomposition and failure, especially in supercritical water environments (temperature>374.15℃, pressure>22.1MPa), where their anti-corrosion and anti-scaling effects are greatly reduced. This is mainly due to the structural isomerization, chain breaking and depolymerization of conventional treatment agents under high temperature and high pressure, resulting in loose and incomplete passivation films of scale inhibitor molecules, which greatly weakens the protective effect on the metal substrate. Due to the low density of the film layer, defects and cracks are prone to occur, providing channels for the penetration of corrosive media, keeping the corrosion rate of carbon steel at a high level (>0.2g / (m 2 h)). In addition, the coordination ability of traditional chelating agents with transition ions such as Fe, Ga, Mg, Si, and Cu is insufficient, making it difficult to stabilize them in the solution, causing them to hydrolyze and precipitate, becoming the nucleation base for scale and oxide scale, aggravating the scaling tendency of equipment, increasing system resistance and thermal resistance, and burying hidden dangers for safe production. It is difficult to meet the increasingly stringent boiler water quality requirements, resulting in aggravated equipment corrosion and the formation of scale deposits, affecting the safe operation and service life of the boiler.

[0003] Polyamine is a common boiler water treatment agent, and its traditional preparation method generally has the problem of poor atom economy. Taking the Michael addition reaction as an example, under alkaline conditions, polymerization side reactions are prone to occur, the products are mixed, and the yield does not exceed 75%. In the process of reductive amination, most routes use equivalent metal hydrides (such as lithium aluminum hydride) as reducing agents, which not only has low atom utilization (E factor>15), but also produces metal salt waste residue, and the post-processing is cumbersome. The use of organic solvents such as toluene will volatilize a large amount of VOCs, aggravating environmental pollution. In addition, there are also limiting factors such as harsh reaction conditions (usually>200℃,>3MPa) and high energy consumption.

[0004] The synthesis process of traditional composite chelating agents used as boiler water treatment agents also faces many challenges. For example, the condensation cyclization reaction has poor selectivity, low cyclization yield (<60%), and is accompanied by a large number of oligomers and structural isomers, and separation and purification are time-consuming and laborious. When introducing functional groups such as carboxyl and sulfonic acid groups, highly toxic and explosive reagents (such as phosgene, SO3) are required, the reaction is highly exothermic, and there are serious safety hazards. At the same time, high temperature and high pressure (temperature>150°C, pressure>2MPa) also bring significant energy loss. Due to the low yield, large amount of solvent used, and E factor as high as 35 or more, the environmental load of the preparation process is heavy.

[0005] Based on the above-mentioned deficiencies of the prior art, the present invention is intended to provide a polyamine furnace water treatment agent for ultra-high temperature and ultra-high pressure water-gas circulation system and a preparation method thereof. Summary of the invention

[0006] The first aspect of the present invention provides a polyamine boiler water treatment agent for an ultra-high temperature and ultra-high pressure water-gas circulation system, wherein the preparation raw materials of the boiler water treatment agent include: polyamine and composite chelating agent, the molar ratio of which is 1:(4-6);

[0007] The preparation method of the polyamine comprises the following steps:

[0008] S1. placing terephthalonitrile and sodium metal in an ethanol solvent and reacting to obtain a mixture 1 (a mixture of sodium p-xylylenediamine salt and acetonitrile, sodium metal, ethanol and terephthalonitrile);

[0009]

[0010] S2. In an ice bath, N-heterocyclobutane was added dropwise to the mixture 1. After the addition was complete, the ice bath was removed and the temperature was raised to react. After the reaction was complete, the solvent was removed by rotary evaporation. The residue was quenched with a saturated ammonium chloride solution and extracted three times with dichloromethane. The organic phase was dried over anhydrous magnesium sulfate, filtered, and distilled under reduced pressure to collect the colorless liquid N, N'-dicyclobutylterephthalamidine at a fraction between 168-172°C, i.e., intermediate 11;

[0011]

[0012] S3. In a high pressure reactor, the intermediate 11, sodium methoxide, methanol and a catalyst activated with hydrogen in advance are placed in a reaction vessel. After the reaction is completed, the reaction is cooled to room temperature, the catalyst is removed by filtration, the filtrate is evaporated to remove methanol, the residue is washed with water, extracted, dried, and purified by vacuum distillation to obtain a colorless viscous liquid 1,4-ditetrahydropyrimidine benzene, i.e., intermediate 12;

[0013]

[0014] S4. The intermediate 21, 1-bromo-3-methylbutane, potassium sulfate and acetonitrile are placed in a reaction vessel. After the reaction is completed, the mixture is cooled to room temperature and filtered. The filter cake is washed with acetonitrile. The filtrate is concentrated by rotary evaporation and purified by column chromatography to obtain a light yellow viscous liquid 1,4-(N,N'-isopentyltetrahydropyrimidine)benzene sulfate, which is then dried in vacuo to obtain the polyamine.

[0015]

[0016] As a preferred embodiment, in S1, the ratio of terephthalonitrile, metallic sodium and ethanol is 1 mol: (2-2.4) mol: (10-20) L, the reaction temperature is 60-70° C., and the reaction time is 3-7 h.

[0017] As a preferred embodiment, in S2, the molar ratio of terephthalonitrile to N-heterocyclobutane is 1:(2-3), the dripping rate is 1 mL / min, the temperature of the heating reaction is 75-85°C, and the heating reaction time is 9-11 h.

[0018] As a preferred embodiment, in S3, the ratio of the intermediate 11, sodium methoxide and the catalyst activated with hydrogen in advance is 1 mol: (3-5) mol: (0.5-1.5) kg, and the ratio of the solvent methanol to the intermediate 11 is 1 L / mol. When activating the catalyst, the pressure of H2 is 4.5-5.5 MPa, the reaction temperature is 170-190° C., the reaction time is 12-36 h, and the catalyst is Raney nickel.

[0019] As a preferred embodiment, in S4, the ratio of intermediate 21, 1-bromo-3-methylbutane, potassium sulfate and acetonitrile is 1 mol: (1.5-2.5) mol: (1.5-2.5) mol: 30L, the reaction temperature is 110-120°C, and the reaction time is 24-48h.

[0020] As a preferred embodiment, the polyamine is 1,4-(N,N'-isopentyltetrahydropyrimidine)benzene sulfate, and the structural formula is shown in Formula I.

[0021]

[0022] The applicant has found that the polyamine obtained by the above method can form a film and coat the metal surface to form a dense protective layer to block the corrosive medium, and the polyamine contains hydrophilic groups, which increases the dispersibility of the molecules in water and expands the anti-corrosion and anti-scaling effect range of the composite system.

[0023] The preparation method of the composite chelating agent comprises the following steps:

[0024] Step 1. L-cysteine, bromoacetic acid, sodium hydroxide and water are mixed and placed in a reaction vessel for reaction to obtain carboxyethylcysteine, i.e., intermediate 21;

[0025]

[0026] Step 2. Under ice bath conditions, sodium 3-bromo-1-propanesulfonate was added dropwise to a tetrahydrofuran solution of trimethylamine. After the addition was complete, the ice bath was removed, the reaction was refluxed, the solvent was evaporated under reduced pressure, and the residue was recrystallized to obtain 3-trimethylaminepropanesulfonic acid inner salt, i.e., intermediate 22;

[0027]

[0028] Step 3. Intermediate 21, intermediate 22, 1,3-dicyclohexylcarbodiimide and N,N-dimethylformamide are mixed and reacted to obtain chelate 1;

[0029]

[0030] Step 4. Mix cardanol, acetaldehyde, diethylenetriamine and ethanol, and react to obtain chelate 2;

[0031]

[0032] Step 5. 8-hydroxyquinoline, 1,3-propanesultone and ethanol are mixed and reacted to obtain chelate 3;

[0033]

[0034] Step 6. Mix chelate 1, chelate 2, chelate 3, N,N-dimethylformamide and potassium sulfate, and react to obtain the composite chelating agent.

[0035] As a preferred embodiment, in step 1, the molar ratio of L-cysteine, bromoacetic acid and sodium hydroxide is 1:(0.9-1.1):(1.5-2.5), the reaction temperature is 10-30°C, and the reaction time is 1.5-2.5h.

[0036] As a preferred embodiment, in step 2, the molar ratio of sodium 3-bromo-1-propanesulfonate to trimethylamine is 1:1.5, and the reflux reaction time is 4-6h.

[0037] As a preferred embodiment, in step 3, the molar ratio of intermediate 21, intermediate 22 and 1,3-dicyclohexylcarbodiimide is 1:(0.9-1.1):(0.5-1.5), the reaction temperature is 60-70°C, and the reaction time is 8-12h.

[0038] Chelate 1 is a chelating group derived from zwitterionic amino acids. It uses L-cysteine ​​as a raw material, introduces a carboxylic acid chelating arm on the side chain thiol group, and simultaneously connects a quaternary ammonium salt-soluble group to the α-amino group. The resulting zwitterionic structure can give it excellent chelating ability and water solubility.

[0039] As a preferred embodiment, in step 4, the molar ratio of cardanol, acetaldehyde and diethylenetriamine is 1:(1-3):(1-3), the reaction temperature is 75-85°C, and the reaction time is 4-6h.

[0040] The applicant found that the chelate 2 obtained by the reaction route is a Mannich reaction product. The specially designed bisphenol hydroxyl group and triimino group can provide 5 chelating sites. In addition, the aromatic ring and the C15 alkyl chain on the aromatic ring can well improve the rigidity and thermal stability of the compound. 2+ and Fe 3+ Chelating with it can further reduce the content of the above ions in boiler water.

[0041] As a preferred embodiment, in step 5, the molar ratio of 8-hydroxyquinoline to 1,3-propanesultone is 1L:(0.9-1.1), the reaction temperature is 110-130° C., and the reaction time is 6-12 h.

[0042] The applicant has found that the chelate group derived from 8-hydroxyquinoline, by introducing a sulfinic acid group at the 2-position of the quinoline ring, can form a stable six-membered chelate ring with a metal cation, while improving the water solubility.

[0043] As a preferred embodiment, in step 6, the molar ratio of chelate 1, chelate 2 and chelate 3 is 1:0.8-1.2:0.8-1.2, the reaction temperature is 90-110°C, and the reaction time is 12-36h.

[0044] As a preferred embodiment, the chelate 1 is a eutectic of [N,N'-dicyclohexylcarbodiimide]N-carboxyethyl-L-cysteine ​​carboxylate-trimethylamine propanesulfonic acid inner salt, and its structural formula is shown in Formula II; the chelate 2 is (2E,6E)-3,6,9,12-tetraazabicyclo[6.4.1]trideca-1(12),2,6,8-tetraene, and its structural formula is shown in Formula III; the chelate 3 is a eutectic of 8-hydroxyquinoline-propanesulfonic acid lactone, and its structural formula is shown in Formula IV;

[0045]

[0046]

[0047] The second aspect of the present invention provides a method for preparing the boiler water treatment agent, which comprises: uniformly mixing a polyamine and a composite chelating agent to obtain the boiler water treatment agent.

[0048] The third aspect of the present invention provides a method for using the boiler water treatment agent, which comprises: adding the boiler water treatment agent to the boiler water to be treated, wherein the ratio of the boiler water treatment agent to the boiler water to be treated is 1 kg: 10 tons.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] 1) The boiler water treatment agent provided by the present invention has a wide applicable temperature and pressure range, can withstand extreme conditions of up to 600°C and 17.8MPa, and has excellent film-forming properties. It can form a denser and more stable protective film layer on the metal surface, providing reliable anti-corrosion protection, and the corrosion rate of carbon steel in boiler water is as low as 0.12g / (m 2 h); strong chelating ability, can effectively chelate with Fe in boiler water 3+ , Cu 2+ , Ca 2+ Mg 2+ , effectively inhibiting the formation of scale and sediment, reducing the burden on equipment operation; good water solubility, with a solubility of up to 26.4g / 100mL at a pH of 7, and sufficiently high efficiency, with scale inhibition efficiencies for CaCO3 and CaSO4 higher than 98% and 95% respectively, reducing the amount of reagents used, reducing energy consumption, and making waste liquid easy to handle; the compound system has both film-forming anti-corrosion and chelating anti-scaling effects, with a reasonable division of labor and synergistic efficiency, which can meet the stringent requirements of supercritical boiler water systems and provide all-round protection for equipment.

[0051] 2) The preparation method of the polyamine provided by the present invention has the advantages of less by-products, high atomic utilization rate, and green environmental protection, and minimizes the generation of waste. For example, in Michael addition, condensation ring and other reactions, only water molecules are removed, and the atomic utilization rate is close to 100%; environmentally friendly solvents such as water and ethanol are used to replace organic solvents, which not only eliminates VOCs emissions but also reduces energy consumption. The aqueous phase reaction avoids the use of organic solvents. Multiple reaction steps use mild conditions such as room temperature or water bath heating instead of high temperature and high pressure, thereby reducing energy consumption.

[0052] 3) The preparation method of the composite chelating agent provided by the present invention has the advantages of high selectivity and conversion rate, short time, low temperature, etc., and the energy consumption is small. In addition, the introduction of secondary amine catalyst improves the conversion efficiency, shortens the reaction time, reduces side reactions, and significantly accelerates the cyclization rate. Reduce separation and purification, further optimize the reaction, improve selectivity, and the product is easy to separate and purify, reducing energy consumption and solvent consumption. When synthesizing the composite chelating agent, the one-pot method obtains the target product with high selectivity, and column chromatography can be used for purification. The entire preparation process has high atomic economy, less pollutant emissions, and low energy consumption, achieving the goal of energy saving and environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 The N,N'-dicyclobutyl terephthalamidine obtained in step S2 of Example 1 of the present invention is 1 H NMR spectrum;

[0054] Figure 2 The 1,4-ditetrahydropyrimidine benzene obtained by S3 in Example 1 of the present invention 1 H NMR spectrum;

[0055] Figure 3 is the polyamine obtained in Example 1 of the present invention 1 H NMR spectrum;

[0056] Figure 4 The N-carboxyethyl-L-cysteine ​​obtained in step 1 of Example 1 of the present invention 1 H NMR spectrum;

[0057] Figure 5 The 3-trimethylamine propanesulfonic acid inner salt obtained in step 2 in Example 1 of the present invention 1 H NMR spectrum;

[0058] Figure 6 is the chelate 1 obtained in step 3 of Example 1 of the present invention 1 H NMR spectrum;

[0059] Figure 7 The chelate 2 synthesized in step 4 of Example 1 of the present invention 1 H NMR spectrum;

[0060] Figure 8 The chelate 3 synthesized in step 6 of Example 1 of the present invention 1 H NMR spectrum. DETAILED DESCRIPTION

[0061] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0062] Unless otherwise specified, the drugs used in the examples were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. Among them, the specification of the Raney nickel catalyst is ≤50 μm, and the product number is R111433.

[0063] Example 1

[0064] This embodiment provides a method for preparing a polyamine and a composite chelating agent, which specifically includes:

[0065] The preparation method of the polyamine comprises the following steps:

[0066] S1. terephthalonitrile and sodium metal are placed in an ethanol solvent for reaction to obtain a sodium diimide salt, namely, mixture 1; the ratio of terephthalonitrile, sodium metal and ethanol is 1 mol: 2.2 mol: 15 L, the reaction temperature is 65 ° C, and the reaction time is 5 h;

[0067]

[0068] S2. In an ice bath, N-heterocyclobutane was added dropwise to mixture 1. After the addition was complete, the ice bath was removed and the temperature was raised to 78°C for 10 hours. After the reaction was complete, the solvent was removed by rotary evaporation. The residue was quenched with saturated ammonium chloride solution and extracted with dichloromethane three times. The organic phase was dried over anhydrous magnesium sulfate, filtered, and distilled under reduced pressure at 2 KPa to collect the colorless liquid N,N'-dicyclobutylterephthalamidine at 168-172°C, i.e., intermediate 11. The molar ratio of terephthalonitrile to N-heterocyclobutane was 1:2.5, and the rate of addition was 1 mL / min.

[0069]

[0070] Take 1.5 mg of the distilled N,N'-dicyclobutylterephthalamidine and dissolve it in 0.55 mL of deuterated DMSO. 1 H NMR test, the test results are as follows Figure 1 shown. 1 H NMR (600MHz, DMSO) δ2.1-2.3(s,4H),3,45-3.59(s,8H),7.30(s,4H),10.68(s,2H).

[0071] S3. In a high pressure reactor, the ratio of intermediate 11, sodium methoxide and catalyst is 1 mol: (3-5) mol: (0.5-1.5) kg, the ratio of intermediate 1 and methanol is 1 mol / L, the reaction temperature is 170-190 ° C, the reaction time is 12-36h, the catalyst is Raney nickel; when activating the catalyst, the pressure of H2 is 4.5-5.5MPa;

[0072]

[0073] Take 1.5 mg of the distilled 1,4-ditetrahydropyrimidine benzene and dissolve it in 0.55 mL of deuterated acetonitrile. 1 H NMR test, the test results are as follows Figure 2 shown. 1 H NMR (600MHz, Acetonitrile) δ2.1-2.4(s,4H),3,42-3.56(s,4H),5.58-5.83(s,4H),8.08(s,4H),8.14(s,2H).

[0074] S4. The intermediate 21, 1-bromo-3-methylbutane, potassium sulfate and acetonitrile are placed in a reaction container. After the reaction is completed, the reaction is cooled to room temperature, filtered, and the filter cake is washed with acetonitrile. The filtrate is concentrated by rotary evaporation and then separated and purified by column chromatography to obtain a light yellow viscous liquid 1,4-(N,N`-isopentyltetrahydropyrimidine)benzene sulfate, which is then dried in vacuo to obtain the polyamine. The ratio of the intermediate 21, 1-bromo-3-methylbutane, potassium sulfate and acetonitrile is 1 mol:2 mol:2 mol:30L, the reaction temperature is 115°C, the reaction time is 36h, the amount of column chromatography silica gel is 50 times that of the raw material, the eluent system V (n-hexane):V (ethyl acetate) = 5:1, the vacuum drying temperature is 50°C, the pressure is 1KPa, and the time is 8h.

[0075]

[0076] The polyamine is 1,4-(N,N'-isopentyltetrahydropyrimidine)benzene sulfate, and its structural formula is shown in Formula I.

[0077]

[0078] Take 1.5 mg of the obtained polyamine product and dissolve it in 0.55 mL of deuterated DMSO. 1 H NMR test, the test results are as follows Figure 3 As shown. Figure 1 The triplet peaks at positions 2, 3, 4, 5, and 7 can be used to determine that the target polyamine component has been successfully synthesized. 1HNMR(600MHz,DMSO)δ0.85-0.91(s,12H),1.55-1.67(s,4H),1.5(s,4H),1.55-1.63 (s,4H),3.19-3.31(s,4H),4.00-4.10(s,4H),4.20-4.35(s,4H),7.65-7.75(s,4H).

[0079] The preparation method of the composite chelating agent comprises the following steps:

[0080] Step 1. L-cysteine, bromoacetic acid, sodium hydroxide and water are mixed, placed in a reaction container, reacted, adjusted to an isoelectric point of 4.8 with dilute hydrochloric acid, filtered, and dried to obtain an intermediate 21, i.e., N-carboxyethyl-L-cysteine; the molar ratio of L-cysteine, bromoacetic acid and sodium hydroxide is 1:1:2, the reaction temperature is 25°C, and the reaction time is 2h;

[0081]

[0082] Take 1.5 mg of N-carboxyethyl-L-cysteine ​​and dissolve it in 0.55 mL of deuterated acetonitrile. 1 H NMR test. The spectrum obtained by the test is shown in Figure 4 . Figure 4 In the above analysis, H at positions 3, 5, and 6 respectively have two heavy peaks, which correspond to the numbers on the molecular formula, so it is believed that a pure N-carboxyethyl-L-cysteine ​​chelate precursor is obtained. 1 H NMR(600MHz,D-ACN)δ2.20-2.35(w,1H),2.75-3.15(w,2H),3.30-3.35(w,1H),3 .45-3.62(s,2H),3.87-3.94(s,1H),12.35-12.45(w,1H),13.01-13.09(w,1H).

[0083] Step 2. Under ice bath conditions, sodium 3-bromo-1-propanesulfonate was added dropwise to a tetrahydrofuran solution of trimethylamine. After the addition was complete, the ice bath was removed, and the reaction was refluxed for 5 h. The solvent was evaporated under reduced pressure, and the residue was recrystallized from acetone / ether (volume ratio 2:1) to obtain 3-trimethylammoniumpropanesulfonic acid inner salt, i.e., intermediate 22; the molar ratio of sodium 3-bromo-1-propanesulfonate to trimethylamine was 1:1.5, and the reaction time was 5 h;

[0084]

[0085] Take 1.5 mg of 3-trimethylammonium propanesulfonic acid inner salt and dissolve it in 0.55 mL of deuterated DMSO. 1 H NMR test. The spectrum obtained by the test is shown in Figure 5 . Figure 5 In the above analysis, H at positions 1, 2, and 3 respectively have two heavy peaks, which correspond to the numbers on the molecular formula, so it is believed that a pure 3-trimethylammoniumpropanesulfonic acid inner salt chelate precursor is obtained. 1 H NMR (600MHz, DMSO) δ2.31-2.59(w,2H),2.51-2.64(w,2H),3.15-3.22(w,2H),3.23(s,9H).

[0086] Step 3. Mix the intermediate 21, the intermediate 22, 1,3-dicyclohexylcarbodiimide and N,N-dimethylformamide, react, remove the solvent under reduced pressure, separate by column chromatography, and obtain a white solid, i.e., chelate 1; the molar ratio of the intermediate 21, the intermediate 22 and 1,3-dicyclohexylcarbodiimide is 1:1:1, the reaction temperature is 65° C., and the reaction time is 10 h;

[0087]

[0088] 1.5 mg of chelate 1 was dissolved in 0.55 mL of deuterated acetonitrile. 1 H NMR test. The spectrum obtained by the test is shown in Figure 6 .Will Figure 6 and Figure 2 and Figure 3 By comparison, we can find Figure 4 There was an obvious shift of H13 and H4 to the low field (left shift), which indicated that N-carboxyethyl-L-cysteine ​​and 3-trimethylammoniumpropanesulfonic acid salt successfully reacted with 1,3-dicyclohexylcarbodiimide (DCC) to form intermolecular forces, thus interfering with the decrease of electron density of H13 and H4. 1 H NMR (600MHz, acetonitrile) δ1.39-1.42(s,2H),1.44-1.46(s,2H),1.47-1.55(s,4H) ),1.59-1.62(s,4H),1.64-1.69(s,4H),1.87-1.90(s,4H),2,26-2.31(s, 2H),2.53-2.56(s,2H),3.10(w,2H)3.21-3.22(s,2H)3.29-3.32(s,12H) ,3.32(s,1H),3.49(s,2H),3.78-3.81(w,1H),5.11(s,1H),13.03(s,1H).

[0089] The chelate 1 is a eutectic compound of [N,N'-dicyclohexylcarbodiimide]N-carboxyethyl-L-cysteine ​​carboxylate-trimethylaminepropanesulfonic acid inner salt, and the structural formula is shown in Formula II;

[0090]

[0091] Step 4. Mix cardanol, acetaldehyde and diethylenetriamine in a molar ratio of 2:2:1, add anhydrous ethanol, the ratio of cardanol to anhydrous ethanol = 1 (mol): 1 (L) as a solvent, and then add catalyst HCl, the ratio of cardanol to HCl is 1 (mol): 100mL. Reflux at 70°C, react for 5h, cool after the reaction, dilute the acid with water, filter after dilution, wash the obtained filter cake with water, and vacuum dry to obtain a light yellow powder, i.e., chelate 2.

[0092]

[0093] Chelate 2

[0094] Chelate 2 1 H NMR spectrum see Figure 7 As can be seen from the figure, H has an obvious high-field shift, which indicates that the increase in H electron density at this location is also affected by C at 2 and 3 and CN=C. This indicates that chelate 2 was successfully synthesized.

[0095] Chelate 2: 1 H NMR (600 MHz, deuterated acetonitrile) δ 0.85-0.91 (s, 6H), 1.24-1.28 (s, 54H), 1.5 (w, 1H), 1.57-1.61 (s, 4H), 2.51-2.55 (s, 4H), 2.65-2.69 (s, 8H), 4.00-4.03 (s, 2H), 4.14-4.17 (s, 2H), 6.60-6.63 (s, 2H), 6.76-6.69 (s, 2H), 7.09-7.12 (s, 2H), 9.27-9.30 (s, 2H).

[0096] The chelate 2 is 4,4'-(((azodiylbis(ethane-2,1-diyl))bis(azodiyl))bis(ethane-1,1-diyl))bis(3-pentadecylphenol), and the structural formula is shown in Formula III;

[0097]

[0098] Step 5. 8-hydroxyquinoline, 1,3-propane sultone and ethanol are mixed and reacted. The reaction solution is poured into ice water, and a yellow precipitate is precipitated. The precipitate is filtered and recrystallized and purified with acetone: water = 4:1 (L:L) to obtain chelate 3; the molar ratio of 8-hydroxyquinoline to 1,3-propane sultone is 1:1, the reaction temperature is 120° C., and the reaction time is 8 h;

[0099]

[0100] Chelate 3 1 H NMR spectrum see Figure 8 . Figure 8 It shows that the H at position 7 has undergone a relatively obvious downfield shift, indicating a decrease in the H electron density at this position, further indicating that the hydroxyl hydrogen of 8-hydroxyquinoline has reacted with the S=O bond of propane sultone to successfully form a coordination compound with a CN=C structure.

[0101] Chelate 3: 1 H NMR (600 MHz, deuterated acetonitrile) δ 2.30-2.49 (s, 2H), 3.10-3.25 (s, 2H), 4.15-4.40 (s, 2H), 6.70-6.85 (s, 1H) 7.55-7.72 (s, 2H), 7.80-7.95 (s, 1H), 8.40-8.55 (s, 1H), 8.85-8.96 (s, 1H), 9.65-9.78 (s, 1H).

[0102] The chelate 3 is a 8-hydroxyquinoline-propane sultone eutectic, and the structural formula is shown in Formula IV;

[0103]

[0104] Step 6. Dissolve chelate 1, chelate 2 and chelate 3 in N,N-dimethylformamide, add potassium sulfate twice the mass of chelate 1, mix and react to obtain the composite chelating agent; the molar ratio of chelate 1, chelate 2 and chelate 3 is 1:1:1, the reaction temperature is 100°C and the reaction time is 24h.

[0105] Example 2

[0106] The present embodiment provides a polyamine furnace water treatment agent for an ultra-high temperature and ultra-high pressure water-gas circulation system. The preparation raw materials include the polyamine prepared in Example 1 and a composite chelating agent in a molar ratio of 1:5. The preparation method includes: uniformly mixing the polyamine and the composite chelating agent to obtain.

[0107] Example 3

[0108] This embodiment provides a polyamine furnace water treatment agent for an ultra-high temperature and ultra-high pressure water-gas circulation system. The preparation raw materials include the polyamine prepared in Example 1 and a composite chelating agent in a molar ratio of 1:4. The preparation method includes: uniformly mixing the polyamine and the composite chelating agent to obtain.

[0109] Example 4

[0110] The present embodiment provides a polyamine furnace water treatment agent for an ultra-high temperature and ultra-high pressure water-gas circulation system. The preparation raw materials include the polyamine prepared in Example 1 and a composite chelating agent in a molar ratio of 1:6. The preparation method includes: uniformly mixing the polyamine and the composite chelating agent to obtain.

[0111] Comparative Example 1

[0112] The specific implementation of this comparative example is the same as that of Example 2, except that the molar ratio of the polyamine to the complex chelating agent is 1:10.

[0113] Comparative Example 2

[0114] The specific implementation manner of this comparative example is the same as that of Example 2, except that the molar ratio of the polyamine to the complex chelating agent is 1:2.

[0115] Comparative Example 3

[0116] The specific implementation manner of this comparative example is the same as that of Example 2, except that the molar ratio of the polyamine to the complex chelating agent is 1:15.

[0117] Comparative Example 4

[0118] The specific implementation manner of this comparative example is the same as that of Example 2, except that the molar ratio of the polyamine to the complex chelating agent is 1:1.

[0119] Performance Testing

[0120] (1) Isothermal titration calorimetry (ITC) was used to measure the reaction between the composite chelating agent prepared in Example 1 and Fe 3+ , Cu 2+ , Ca 2+ Mg 2+ The binding constant (Ka) and chelation enthalpy change (ΔH) of the ions are measured to evaluate their chelation ability. The specific measurement method is: 0.01 mol of the composite chelating agent is dissolved in 10 g of deionized water, and placed in the reaction pool and the sample pool respectively, and the reaction pool and the sample pool are maintained at 25°C. 0.05 mol / L of the sulfate aqueous solution of the above four ions is injected into the reaction pool, and the components in the reaction pool are monitored for heat and pressure, so as to calculate the chelation enthalpy change of the chelating agent for the above ions.

[0121] The calculation formula for the chelation enthalpy change (in kJ / mol) is: dH=du+Vdp.

[0122] Among them, dH represents the chelation enthalpy change, du represents the internal energy increment of the system, V represents the system volume, and p represents the system pressure increment.

[0123] Binding constant Ka (in mol -1 ) is calculated as:

[0124]

[0125] The control group was EDTA. The results are shown in Table 1.

[0126] Table 1

[0127]

[0128] As shown in Table 1, the chelating ability of the composite chelating agent prepared by the present invention is better than that of the commonly used EDTA. The reason for this characteristic is that the special structure of the chelating agent can form a stable multi-element chelating ring with metal ions, with abundant chelating sites and strong chelating ability, and the introduction of the double N hetero seven-membered ring and 8-hydroxyquinoline ring improves the selectivity for transition metal ions.

[0129] (2) The water solubility of the composite chelating agent prepared in Example 1 at room temperature was evaluated by measuring the solubility of the composite chelating agent in buffer solutions of different pH values ​​(5.0-9.0) (the buffer solution of pH=5 was acetic acid-sodium acetate solution, the buffer solution of pH=7 was phosphoric acid-sodium phosphate solution, and the buffer solution of pH=9 was ammonia-ammonium chloride buffer solution). The specific measuring method was as follows:

[0130] The control group was chelating agent NTA (nitrilotriacetic acid), and the results are shown in Table 2.

[0131] Table 2

[0132] pH = 5 pH = 7 pH=9 Example 1 12.8g / 100mL 26.4g / 100mL 37.2g / 100mL Control group 9.1g / 100mL 21.4g / 100mL 26.2g / 100mL

[0133] As shown in Table 2, the water solubility of the composite chelating agent prepared by the present invention is better than that of the chelating agent NTA, indicating that the introduced quaternary ammonium group, sulfonic acid group, thiol group, carboxyl group and other groups greatly enhance the hydrophilicity of the composite chelating agent, so that it has excellent water solubility in a wide pH range, meeting the actual needs of industrial water systems.

[0134] (3) A rotating hanging plate test was used to evaluate the anti-corrosion effect of the boiler water treatment agent prepared in the embodiment and the comparative example on carbon steel. The specific method is: after adding the boiler water treatment agent to the simulated boiler water (600°C, 17.8MPa), the center of a square carbon steel with a thickness of 0.5 cm and a length of 10 cm was connected to the engine (speed of 100r / min) and kept for 30 days to test the corrosion rate of the carbon steel. The calculation formula is:

[0135] The addition amount of boiler water treatment agent in the embodiment and the comparative example is 5g:1 ton, and the comparative control group does not add any agent. The results are shown in Table 3.

[0136] Table 3

[0137]

[0138]

[0139] As shown in Table 3, the addition of the boiler water treatment agent prepared by the present invention has an inhibition efficiency of 96.2% compared to that without the use of the boiler water treatment agent, which proves that the synergistic combination of the composite chelating agent and the polyamine can effectively block the corrosive medium and greatly improve the anti-corrosion performance. According to the results of Examples 3-4 and Comparative Examples 1-4, it can be seen that the best corrosion resistance can be obtained by adopting the optimal ratio described in the present invention.

[0140] (4) The scale inhibition rate of the boiler water treatment agent prepared in the embodiment and the comparative example on calcium carbonate scale and calcium sulfate scale was determined by the static non-evaporation concentration scale inhibition method. The experimental method was in accordance with GB / T 16632-1996. The experimental conditions were: in terms of CaCO3, the test water c(Ca 2+ )=360mg / L,c(HCO3 - )=700mg / L, experimental temperature 80±1℃, experimental time 8h.

[0141] The addition amount of boiler water treatment agent in the embodiment and the comparative example is 5g:1 ton, and the control group is commercially available IDA (dicarboxyethylamine). The results are shown in Table 4.

[0142] Table 4

[0143] Calcium carbonate scale% Calcium sulfate scale% Example 2 98.5 96.1 Example 3 94.1 94.9 Example 4 96.2 95.6 Comparative Example 1 90.1 88.7 Comparative Example 2 88.4 84.5 Comparative Example 3 89.1 87.4 Comparative Example 4 84.2 81.9 Control group 24％ 45％

[0144] It can be seen from Table 4 that the composite chelating agent prepared by the present invention can effectively chelate scale ions and inhibit the tendency to scale formation by virtue of its excellent chelating ability, and the polyamine makes it difficult for scale crystals to be adsorbed and deposited through surface modification, and the two work together to completely block the scaling process. The commercially available chelating agents are difficult to achieve the inhibitory effect on metal cations, and the effect is difficult to meet industrial needs.

[0145] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A polyamine-based boiler water treatment agent, characterized in that: The raw materials for preparing the boiler water treatment agent include: polyamine and composite chelating agent, the molar ratio of which is 1:(4-6); The preparation method of the polyamine comprises the following steps: S1. placing terephthalonitrile and sodium metal in an ethanol solvent for reaction to obtain a mixture 1; The ratio of terephthalonitrile, sodium metal and ethanol is 1 mol: (2-2.4) mol: (10-20) L; S2. In an ice bath, N-heterocyclobutane is added dropwise to the mixture 1. After the addition is complete, the ice bath is removed and the temperature is raised to react. After the reaction is complete, the solvent is removed by rotary evaporation. The residue is quenched with a saturated ammonium chloride solution and extracted with dichloromethane. The organic phase is dried over anhydrous magnesium sulfate, filtered, and distilled under reduced pressure to collect the colorless liquid N,N'-dicyclobutylterephthalamidine at a fraction between 168-172°C, i.e., intermediate 11; S3. In a high pressure reactor, the intermediate 11, sodium methoxide, methanol and a catalyst activated with hydrogen in advance were placed in a reaction vessel. After the reaction was completed, the reaction was cooled to room temperature, the catalyst was removed by filtration, the filtrate was evaporated to remove methanol, the residue was washed with water, extracted, dried, and purified by vacuum distillation to obtain a colorless viscous liquid, namely, the intermediate 12; The ratio of intermediate 11, sodium methoxide and catalyst is 1 mol: (3-5) mol: (0.5-1.5) kg; the reaction temperature is 170-190° C.; the catalyst is Raney nickel; S4. The intermediate 12, 1-bromo-3-methylbutane, potassium sulfate and acetonitrile are placed in a reaction vessel. After the reaction is completed, the mixture is cooled to room temperature and filtered. The filter cake is washed with acetonitrile. The filtrate is concentrated by rotary evaporation and purified by column chromatography to obtain a light yellow viscous liquid. The polyamine is obtained after vacuum drying. The polyamine is 1,4-(N,N'-isopentyltetrahydropyrimidine)benzene sulfate, and the structural formula is shown in Formula I. The preparation method of the composite chelating agent comprises the following steps: Step 1. L-cysteine, bromoacetic acid, sodium hydroxide and water are mixed and placed in a reaction vessel for reaction to obtain intermediate 21; Step 2. Under ice bath conditions, sodium 3-bromo-1-propanesulfonate was added dropwise to a solution of trimethylamine in tetrahydrofuran. After the addition was complete, the ice bath was removed, the reaction was refluxed, the solvent was evaporated under reduced pressure, and the residue was recrystallized to obtain intermediate 22; Step 3. Mix the intermediate 21, the intermediate 22, 1,3-dicyclohexylcarbodiimide and N,N-dimethylformamide, and react to obtain a chelate 1; the chelate 1 is a eutectic compound of [N,N'-dicyclohexylcarbodiimide]N-carboxyethyl-L-cysteine ​​carboxylate-trimethylaminepropanesulfonic acid inner salt, and the structural formula is shown in Formula II; Step 4. Mix cardanol, acetaldehyde and diethylenetriamine, place in a reaction bottle, add solvent and catalyst, react, and obtain chelate 2; the structural formula of chelate 2 is shown in formula III; Step 5. 8-hydroxyquinoline, 1,3-propane sultone and ethanol are mixed and reacted to obtain chelate 3; the chelate 3 is a 8-hydroxyquinoline-propane sultone eutectic, and the structural formula is shown in Formula IV; Step 6. Mix chelate 1, chelate 2, chelate 3, N,N-dimethylformamide and potassium sulfate, and react to obtain the composite chelating agent.

2. The boiler water treatment agent according to claim 1, characterized in that: In S1, the reaction temperature is 60-70°C and the reaction time is 3-7h; The molar ratio of the N-heterocyclobutane in S2 to the terephthalonitrile in S1 is (2-3):1, the dripping rate is 1 mL / min, the temperature of the heating reaction is 75-85° C., and the heating reaction time is 9-11 h.

3. The boiler water treatment agent according to claim 1, characterized in that In S3, the ratio of intermediate 11 to methanol is 1 mol / L, the reaction time is 12-36 h, and the pressure of H2 introduced during catalyst activation is 4.5-5.5 MPa; In S4, the ratio of intermediate 12, 1-bromo-3-methylbutane, potassium sulfate and acetonitrile is 1 mol: (1.5-2.5) mol: (1.5-2.5) mol: 30 L, the reaction temperature is 110-120° C., and the reaction time is 24-48 h.

4. The boiler water treatment agent according to claim 1, characterized in that In the step 1, the molar ratio of L-cysteine, bromoacetic acid and sodium hydroxide is 1:(0.9-1.1):(1.5-2.5), the reaction temperature is 10-30° C., and the reaction time is 1.5-2.5 h; In the step 2, the molar ratio of sodium 3-bromo-1-propanesulfonate to trimethylamine is 1:1.5, and the reflux reaction time is 4-6 hours.

5. The boiler water treatment agent according to claim 1, characterized in that: In the step 3, the molar ratio of intermediate 21, intermediate 22, and 1,3-dicyclohexylcarbodiimide is 1:(0.9-1.1): (0.5-1.5), the reaction temperature is 60-70°C, and the reaction time is 8-12h; In step 4, the molar ratio of diethylenetriamine, acetaldehyde and cardanol is 1:(1-3):(1-3), the reaction temperature is 75-85° C., and the reaction time is 4-6 hours.

6. The boiler water treatment agent according to claim 1, characterized in that: In the step 5, the molar ratio of 8-hydroxyquinoline to 1,3-propane sultone is 1:(0.9-1.1), the reaction temperature is 110-130° C., and the reaction time is 6-12 h; In step 6, the molar ratio of chelate 1, chelate 2 and chelate 3 is 1:(0.8-1.2):(0.8-1.2), the reaction temperature is 90-110° C., and the reaction time is 12-36 h.

7. A method for preparing a boiler water treatment agent according to any one of claims 1 to 6, characterized in that: The preparation method comprises: uniformly mixing the polyamine and the composite chelating agent to obtain the product.

8. A method for using the boiler water treatment agent according to any one of claims 1 to 6, characterized in that: The use method comprises: adding a boiler water treatment agent to the boiler water to be treated, wherein the ratio of the boiler water treatment agent to the boiler water to be treated is 5 g:1 ton.

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