Multi-metal washing corrosion inhibitor and preparation method thereof

Abstract

The invention belongs to the technical field of marine corrosion protection, and particularly relates to a multi-metal flushing corrosion inhibitor and a preparation method thereof, benzotriazole and isocyanate propyl triethoxy silane or isocyanate propyl trimethoxy silane are used as raw materials, and a novel benzotriazole corrosion inhibitor containing a silane structure is synthesized through catalysis. The benzotriazole containing the silane structure is compounded with corrosion inhibitors such as organic acid salt, organic acid polymer and organosilane to form the multi-metal flushing corrosion inhibitor for steel, aluminum alloy and copper, which does not contain nitrite, phosphate and heavy metals (lead, cadmium and mercury). When in use, the corrosion inhibitor is diluted to 0.2-0.5%, the corrosion inhibitor is applied to flushing protection of offshore drilling platforms, marine investigation equipment and coastal facilities through flushing and spraying processes, a corrosion inhibitor protective film is formed on the basis of removing a surface salt film, corrosion of multiple metals such as steel, aluminum alloy and copper alloy in a marine atmospheric environment is effectively inhibited, and the corrosion inhibitor has good environmental friendliness.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of marine corrosion protection, and particularly relates to a multi-metal flushing corrosion inhibitor and a preparation method thereof. BACKGROUND

[0002] Steel, aluminum alloy, copper and copper alloy are metal materials widely used in marine equipment. The high salt and high humidity conditions in the marine atmospheric environment can accelerate the corrosion process of metal equipment. The electrochemical corrosion caused by salt deposition can increase the corrosion rate of materials by 3-5 times. The flushing corrosion inhibitor forms a protective film layer while removing surface salt through the spraying process, becoming a key protection method for equipment such as ships and aircrafts.

[0003] In the field of ships, Chinese patent 200810015561.3 discloses a flushing corrosion inhibitor for ships. The raw material composition includes organic phosphonic acid, sodium molybdate, azoles, organic phosphonic acid, sulfonic acid copolymer and polyaspartic acid. The organic phosphonic acid, organic phosphonic acid, sulfonic acid copolymer, polyaspartic acid are first stirred and mixed uniformly according to the volume ratio of 2-4:1-2:1-2:1-2, and then stand for 10-15 minutes. Then, according to the volume of the mixed solution, 0.2-0.6 g / 100 mL of sodium molybdate and azoles are added respectively, and stirring is continued until the mixture is uniform. Then, dilute with fresh water according to the volume ratio of 400-500 times to obtain the flushing corrosion inhibitor for ships. The organic phosphonic acid includes hydroxyethylidene diphosphonic acid, aminodimethyl phosphonic acid, ethylene diamine tetramethylene phosphonic acid, 2-hydroxy phosphono acetic acid, diethylene triamine penta methylene phosphonic acid sodium or hexamethylene diamine tetramethylene phosphonic acid sodium. The azoles include mercapto benzothiazole, benzotriazole or methyl benzotriazole. The sulfonic acid copolymer includes styrene sulfonic acid-maleic anhydride copolymer or acrylic acid-2-acrylamido-2'-methyl propyl sulfonic acid copolymer. Chinese patent 202311198972.1 discloses a flushing corrosion inhibitor for ships. The composition includes modified polyaspartic acid prepared from di-carbonyl compound grafted polyaspartic acid and enzymes. The di-carbonyl compound includes malonic acid diethyl ester or 2-benzyl benzoyl acetic acid ethyl ester. The preparation method of the modified polyaspartic acid includes the following steps: adding the di-carbonyl compound into NaOH for reaction, and then adding poly succinimide for further reaction. Then, adjust the pH to neutral, wash the product to obtain the modified polyaspartic acid. The enzymes include lipase and / or protease. The flushing corrosion inhibitor for ships further includes silicon dioxide and chitosan. The silicon dioxide is mesoporous silicon dioxide.

[0004] In the field of aviation, the corrosion inhibition technology focuses on material compatibility and rapid construction performance. Chinese patent 202010661316.0 discloses a non-toxic corrosion inhibitor, which is a tea plant extract, including: phenol C6H6O, flavone C 15 H10 O2, tannin C 76 H 52 O 46 , the mass percentage of phenol content is 10%-25%, the mass percentage of flavonoid content is 20%-35%, and the mass percentage of tannin content is 5%-20%, and the preparation method comprises the following steps: step one, cleaning treatment is performed on tea plant precursors; step two, the tea plant precursors treated in step one are placed in a constant temperature environment of 20-50 DEG C for fermentation treatment for 24-36 hours; step three, the product obtained after fermentation in step two is subjected to drying treatment in the range of 60-140 DEG C; step four, the tea plants obtained in step three are subjected to ball milling under the conditions of a rotating speed of 20-90 r / min and a ball-to-material ratio of 0.1-0.9 for 5-20 hours; step five, the tea powder after ball milling in step four is subjected to pressure boiling at 1.0-1.5 atm and 70-100 DEG C; step six, the solution after pressure boiling in step five is filtered to remove larger particles; step seven, the filtrate obtained in step six is subjected to drying treatment in the range of 60-140 DEG C, and the solid obtained after drying is ground and dissolved in ethanol; and step eight, the solution obtained in step seven is subjected to drying treatment in the range of 60-140 DEG C, and the solid obtained after drying is ground to obtain an extract, namely, the corrosion inhibitor. A non-toxic corrosion inhibitor disclosed in Chinese patent 202011078925.X is nitrogen-doped carbon quantum dots, and the carbon dots on the surface of the nitrogen-doped carbon quantum dots have amino, guanidino and hydroxyl functional groups. The preparation method comprises the following steps: step one, weighing precursor materials and dissolving them in a proper amount of deionized water; step two, ultrasonic dispersion of the solution prepared in step one for 10-40 minutes; step three, hydrothermal reaction of the solution after ultrasonic dispersion in step two at 130-180 DEG C for 1-6 hours, and then cooling to room temperature; step four, centrifugation of the nitrogen-doped carbon quantum dot solution obtained in step three at a rotating speed of 6000-12000 for 10-60 minutes to remove larger particles in the solution; and step five, filtration of the solution after centrifugation in step five to obtain the corrosion inhibitor. The precursor is amino guanidine hydrochloride and citric acid, the amount of amino guanidine hydrochloride is 0.25-1 g, the amount of citric acid is 0.1-0.5 g, and the amount of deionized water is 1-5 mL. A water-based aircraft surface cleaning agent developed by China Aviation Materials Aviation New Material Co., Ltd. contains a metal corrosion inhibitor, which can inhibit the corrosion of an aluminum matrix of an aircraft.

[0005] Internationally, the proportion of bio-based materials has increased significantly: modified polyaspartic acid has become a hot material to replace traditional molybdate / phosphonate due to its biodegradability (30-day degradation rate >80%) and strong coordination ability with metals. European patent EP3257946B1 uses a similar grafting technique to copolymerize polyaspartic acid and itaconic acid, improving its stability in seawater. US20220169972A1 introduces a chitosan-zinc complex to enhance the corrosion inhibition effect by using the cathodic protection effect of zinc ions.

[0006] In general, the flushing corrosion inhibitors in the prior art mainly focus on two aspects of marine flushing and aircraft flushing, and are mostly for one kind of main metal material, such as marine flushing corrosion inhibitor mainly facing ship steel, and aircraft flushing corrosion inhibitor mainly facing aluminum alloy material, but in actual use process, good compatibility for other materials is required. Therefore, a compound type multi-metal flushing corrosion inhibitor is developed and designed, which can play an inhibiting protection role on steel, aluminum alloy material, copper and copper alloy. SUMMARY

[0007] The purpose of the present application is to overcome the shortcomings of the prior art, and to develop and design a multi-metal flushing corrosion inhibitor and a preparation method thereof to meet the corrosion protection requirements of marine equipment and coastal facilities in marine atmospheric environment and dry-wet alternating environment.

[0008] In order to achieve the above-mentioned purpose, the preparation method of the multi-metal flushing corrosion inhibitor according to the present application uses benzotriazole and propyl triethoxysilane isocyanate or propyl trimethoxysilane isocyanate as raw materials to catalytically synthesize benzotriazole containing silane structure, and then the benzotriazole containing silane structure is compounded with other various environment-friendly corrosion inhibitors to prepare the multi-metal flushing corrosion inhibitor. The multi-metal flushing corrosion inhibitor can remove the salt film on the surface of marine equipment through the flushing process, form a corrosion inhibitor protective film, and inhibit the corrosion of various metals such as steel, aluminum alloy, copper alloy and the like in marine atmospheric environment.

[0009] The specific process of the preparation method is as follows:

[0010] (1) Synthesis of benzotriazole containing silane structure

[0011] O.04mol of benzotriazole, ZnCl2 and organic solvent are stirred and dissolved according to the ratio of 4.76g:0.5g:40ml;

[0012] Nitrogen is introduced for protection, and then O.04mol of propyl triethoxysilane isocyanate or propyl trimethoxysilane isocyanate is added, and stirring is continued, and the reaction is carried out at 70℃ for 12-18h;

[0013] The obtained product is cooled to room temperature, filtered, the filter residue is washed, and the filtrate is combined. The filtrate is concentrated under reduced pressure at 40℃, and the purified product is obtained by column chromatography;

[0014] The organic solvent is anhydrous acetonitrile or tetrahydrofuran;

[0015] When propyl triethoxysilane isocyanate is used for reaction, the product is N-[3-(triethoxysilyl)propyl]-1H-benzotriazole-1-carboxamide, and the structure is as shown in Figure 1 ;

[0016] When reacted with propyltrimethoxysilane isocyanate, the product is N-[3-(trimethoxysilyl)propyl]-1H-benzotriazole-1-carboxamide, and the structure is as shown in Figure 2

[0017] (2) Multi-metal flushing corrosion inhibitor

[0018] The silane structure-containing benzotriazole, organic acid salt, organic acid polymer, organosilane and inorganic salt are dissolved in anhydrous ethanol respectively to prepare concentrated solutions with a mass percentage of 20-50%, and are mixed according to a mass ratio of (1-3):(2-3):(2-3):(1-3):(1-2) to obtain a multi-metal flushing corrosion inhibitor for protecting steel, aluminum alloy, copper and copper alloy.

[0019] The organic acid salt is one of zinc gluconate, calcium gluconate and sodium citrate, or a mixture of two or more thereof.

[0020] The organic acid polymer is one of polyaspartic acid and acrylic acid polymer, or a mixture of two thereof.

[0021] The organosilane is one of methyltriethoxysilane, tetraethyl orthosilicate and 3-glycidyloxypropyltriethoxysilane, or a mixture of two or more thereof.

[0022] The inorganic salt is one of zinc sulfate and sodium molybdate, or a mixture of two thereof.

[0023] The multi-metal flushing corrosion inhibitor of the present application is used by being diluted to a mass percentage of 0.2-0.5%, and the synergistic effect of the silane structure-containing benzotriazole and the organic acid polymer and the organosilane forms a dense adsorption film to inhibit the corrosion of steel, aluminum alloy, copper and copper alloy.

[0024] When steel and aluminum alloy are the main protection targets, the multi-metal flushing corrosion inhibitor is simplified to be composed of the organic acid salt, the organic acid polymer, the organosilane and the inorganic salt according to a mass ratio of (2-3):(2-3):(1-3):(1-2) to save cost.

[0025] Compared with the prior art, the multi-metal flushing corrosion inhibitor is formed by compounding the new corrosion inhibitor containing silane structure benzotriazole, and has the siloxane structure and benzotriazole structure, and has the corrosion inhibition performance for copper alloy and aluminum alloy. The corrosion inhibitor can be applied to the flushing protection of offshore drilling platforms, marine research equipment and coastal facilities through the flushing and spraying process. The corrosion inhibitor forms a protective film on the basis of removing the surface salt film, effectively inhibits the corrosion of steel, aluminum alloy, copper alloy and other metals in the marine atmosphere, is environmentally friendly, economically efficient (low use concentration), multi-metal corrosion inhibiting, and can be widely applied to the flushing protection of marine equipment shells, ship decks and marine coastal equipment, and has good application prospect.​ Attached image description:

[0026] Figure 1 This is a schematic diagram of the structure of N-[3-(triethoxysilyl)propyl]-1H-benzotriazole-1-carboxamide involved in this invention.

[0027] Figure 2 This is a schematic diagram of the structure of N-[3-(trimethoxysilyl)propyl]-1H-benzotriazole-1-carboxamide involved in this invention. Detailed implementation method:

[0028] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0029] Example 1:

[0030] The specific process of the multi-metal flushing corrosion inhibitor and its preparation method involved in this embodiment is as follows:

[0031] (1) Synthesis of benzotriazole containing silane structure

[0032] Add 4.76 g of benzotriazole, 0.5 g of ZnCl2, and 40 mL of tetrahydrofuran to a 250 mL three-necked flask in sequence, and stir to dissolve.

[0033] Under nitrogen protection, 9.88 g of propyltriethoxysilane isocyanate was added, and the mixture was stirred continuously and reacted at 70 °C for 12 h.

[0034] The obtained product was cooled to room temperature, filtered, and the filter residue was washed with 10 ml of tetrahydrofuran. The filtrates were combined and concentrated under reduced pressure at 40 °C. The product was then separated by column chromatography and concentrated to obtain the purified product N-[3-(triethoxysilyl)propyl]-1H-benzotriazole-1-carboxamide.

[0035] (2) Compound multi-metal flushing corrosion inhibitor

[0036] Add 2.0 g of N-[3-(triethoxysilyl)propyl]-1H-benzotriazole-1-carboxamide, 3.0 g of zinc gluconate, 3.0 g of acrylic polymer, 2.0 g of methyltriethoxysilane, 2.0 g of zinc sulfate, and 36.0 g of anhydrous ethanol to a 100 mL clean beaker using an electronic balance. Stir thoroughly to prepare a concentrated solution of a multi-metal composite corrosion inhibitor with a solid content of 25%.

[0037] Performance evaluation of the compounded multi-metal flushing corrosion inhibitor:

[0038] The copper alloy, aluminum alloy and Q235 steel were cut into test samples with a size of 6 cm x 4 cm x 0.5 cm, polished, cleaned with acetone and dried for standby. The multi-metal flushing corrosion inhibitor was diluted with deionized water to a solution with a mass percentage concentration of 0.25%;

[0039] The blank control sample and the test sample were weighed and then immersed in natural seawater for 30 minutes. After being taken out, the samples were hung in an environmental test chamber. After being taken out, the samples were immersed in the flushing corrosion inhibitor for 10 minutes. After being taken out, the samples were hung in the environmental test chamber. The chamber was filled with natural seawater to simulate the marine atmospheric environment.

[0040] After the test at a temperature of 40℃ and a humidity of 80% for 15 days, the corrosion products were removed, and the samples were weighed again. The corrosion inhibition rate of the corrosion inhibitor was calculated according to the formula: corrosion inhibition rate = [(weight loss of the control sample - weight loss of the inhibited sample) / weight loss of the control sample] x 100%.

[0041] The results show that the corrosion inhibition rate of the multi-metal complex corrosion inhibitor for Q235 steel is 83.1%, for aluminum alloy is 73.8%, and for copper alloy is 78.44%.

Claims

1. A method for preparing a multi-metal rinse corrosion inhibitor, characterized in that, A multi-metal flushing corrosion inhibitor was prepared by catalytically synthesizing benzotriazole with a silane structure using benzotriazole and propyltriethoxysilane or propyltrimethoxysilane isocyanate as raw materials, and then compounding the benzotriazole with an environmentally friendly corrosion inhibitor.

2. The method according to claim 1, wherein the method is characterized by, The specific process is as follows: (1) Synthesis of benzotriazole containing silane structure Benzotriazole, ZnCl2, and an organic solvent are stirred and dissolved. Nitrogen gas was introduced for protection, and then propyltriethoxysilane or propyltrimethoxysilane was added. The mixture was stirred continuously and reacted at 70°C for 12-18 hours. The obtained product was cooled to room temperature, filtered, the filter residue was washed, the filtrates were combined, and the filtrates were concentrated under reduced pressure at 40°C. The purified product was obtained by column chromatography. (2) Compound multi-metal flushing corrosion inhibitor Silane-containing benzotriazole, organic acid salts, organic acid polymers, organosilanes, and inorganic salts were dissolved in anhydrous ethanol to prepare concentrated solutions with a mass percentage concentration of 20-50%. These solutions were then mixed in a mass ratio of (1-3):(2-3):(2-3):(1-3):(1-2) to obtain a multi-metal flushing corrosion inhibitor targeting steel, aluminum alloys, copper, and copper alloys.

3. The method according to claim 1 or 2, characterized in that, The prepared multi-metal flushing corrosion inhibitor removes the salt film on the surface of marine equipment through a flushing process, forming a protective film that inhibits the corrosion of steel, aluminum alloys, and copper alloys in the marine atmospheric environment.

4. The method according to claim 3, wherein the method is characterized by, When used, dilute to a mass percentage concentration of 0.2-0.5%. The synergistic effect of silane-containing benzotriazole with organic acid polymers and organosilanes forms a dense adsorption film, which inhibits the corrosion of steel, aluminum alloys, copper and copper alloys.

5. The method for preparing a multi-metal rinse corrosion inhibitor according to claim 1 or 2, characterized in that, Benzotriazole, ZnCl2, and an organic solvent were dissolved by stirring at a ratio of 4.76 g: 0.5 g: 40 ml. Benzotriazole and propyltriethoxysilane or propyltrimethoxysilane are both 0.04 mol.

6. The method for preparing a multi-metal flushing corrosion inhibitor according to claim 2, characterized in that, The organic solvent in step (1) is anhydrous acetonitrile or tetrahydrofuran.

7. A method of preparing a multi-metal rinse corrosion inhibitor according to claim 2, characterized in that, The organic acid salt in step (2) is one or a mixture of two or more of zinc gluconate, calcium gluconate, and sodium citrate; The organic acid polymer is one or a mixture of two of polyaspartic acid and acrylic acid polymer; The organosilane is one or a mixture of two or more of methyltriethoxysilane, tetraethyl orthosilicate, and 3-glycidyl etheroxypropyltriethoxysilane; The inorganic salt is one or a mixture of two of zinc sulfate and sodium molybdate.

8. The method for preparing a multi-metal flushing corrosion inhibitor according to claim 2, characterized in that, When steel and aluminum alloys are the targets of protection, it is simplified to a compound composed of organic acid salts, organic acid polymers, organosilanes and inorganic salts in a mass ratio of (2-3):(2-3):(1-3):(1-2).

Images