Alkyl diphosphonic acid composition as well as preparation and purification method and application thereof

Abstract

The invention relates to an alkyl diphosphonic acid composition as well as a preparation and purification method and application thereof, and belongs to the technical field of preparation of alkyl diphosphonic acid compositions. The alkyl diphosphonic acid composition comprises the following components in percentage by mass: more than or equal to 90% of diphosphonic acid compound with a structural formula I, 0-10% of phosphorous acid, 0-10% of phosphoric acid, 0-10% of alkyl phosphonic acid, 0-10% of dialkyl phosphonic acid and 0-10% of organic acid, the alkyl diphosphonic acid composition can be applied to metal surface anti-corrosion treatment, such as deposition on iron, aluminum, copper and zinc to form a self-assembled single layer or organic phosphonate multilayer, so that the metal corrosion resistance is enhanced, and the inhibition effect on metal corrosion is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of alkyl bisphosphonic acid compositions, and relates to an alkyl bisphosphonic acid composition and a preparation and purification method and application thereof. Background Art

[0002] Due to its strong chelation with metal ions, the alkyl bisphosphonic acid composition can coordinate with the metal to form a strong binding force, promoting the formation of a densely packed and stable phosphonic acid monolayer or a multilayer of organic phosphonates on the surface of metals such as iron, aluminum, copper, zinc, etc., which can effectively prevent water and oxygen from diffusing to the metal bottom layer to achieve corrosion inhibition of metals such as iron, aluminum, copper, zinc, etc., so that it has a wide range of applications in the fields of metal material corrosion resistance. For example: dodecyl bisphosphonic acid, hexadecyl bisphosphonic acid, and octadecyl bisphosphonic acid directly converted into the corresponding primary amine in one pot can form a stable alkyl phosphonic acid monolayer on the surface of stainless steel metal, which plays a corrosion inhibition role. Dodecyl bisphosphonates can modify the surface of titanium dioxide to form a stable surface structure.

[0003] There are currently a variety of methods for preparing and purifying alkyl bisphosphonic acids, such as using hydrochloric acid or trimethylsilane as a specific catalyst to catalyze a hydrolysis reaction under microwave radiation or conventional conditions, followed by further purification using methanol or isopropanol. However, the products obtained by these methods cannot meet the requirements for corrosion inhibition of metals such as iron, aluminum, copper, and zinc due to the introduction of hydrochloric acid and other impurities during the preparation and purification process. Therefore, it is urgent to develop a new alkyl bisphosphonic acid composition with anti-corrosion effect on metal surfaces. Summary of the invention

[0004] The purpose of the present invention is to provide an alkyl bisphosphonic acid composition and a preparation and purification method and application thereof. The prepared alkyl bisphosphonic acid composition has an excellent effect of improving the corrosion resistance of metal surfaces.

[0005] The purpose of the present invention can be achieved through the following technical solutions: An alkyl bisphosphonic acid composition, which comprises, by mass percentage, ≥90% of a bisphosphonic acid compound having structural formula I, 0-10% of phosphorous acid, 0-10% of phosphoric acid, 0-10% of alkyl phosphonic acid, 0-10% of dialkyl phosphonic acid, and 0-10% of organic acid; The structure of the bisphosphonic acid compound having structural formula I is:

[0006] Wherein R is a straight chain or branched alkyl group with carbon atoms ranging from C1 to C20, and the branched chain is an alkyl group with carbon atoms ranging from C1 to C19.

[0007] A method for preparing and purifying an alkyl bisphosphonic acid composition comprises the following steps: S1, adding an alkyl bisphosphonic acid tetraester raw material containing impurities into a reactor, and continuously passing hot water or water vapor into the reactor for hydrolysis for 6 to 12 hours, and obtaining a crude product of an alkyl bisphosphonic acid composition after the hydrolysis is completed; S2, dropwise adding an organic acid dispersant in an amount of 1 to 10 times the mass of the crude product of the alkyl bisphosphonic acid into the reaction kettle, dispersing the crude product of the alkyl bisphosphonic acid composition to obtain a powdery dispersion; S3. Then, the powdered dispersed product and the organic acid are poured out and filtered, and the obtained product is placed in a drying oven and dried to obtain the alkyl bisphosphonic acid composition.

[0008] As a preferred technical solution of the present invention, in step S1, the structure of the alkyl bisphosphonate tetraester raw material is a straight-chain or branched alkyl bisphosphonate with a carbon number of C1 to C20, wherein the branch contains an alkyl group with a carbon number of C1 to C19, and the ester group is a straight-chain or branched alkyl ester with a carbon number of C1 to C20.

[0009] As a preferred technical solution of the present invention, in step S1, the impurities are phosphites and phosphonate substances, including phosphite diesters, phosphite triesters, alkyl phosphonate diesters, dialkyl phosphonates, and phosphate triesters, wherein the alkyl group in the impurities is a straight-chain or branched alkyl group with a carbon number of C1 to C20, and the ester group in the impurities is a straight-chain or branched alkyl ester with a carbon number of C1 to C20.

[0010] As a preferred technical solution of the present invention, in step S1, the mass percentage range of impurities in the alkyl bisphosphonate tetraester raw material is as follows: phosphite diester is 0-15%, phosphite triester is 0-25%, alkyl phosphonic acid diester is 0-25%, dialkyl phosphonate is 0-10%, and phosphate triester is 0-15%.

[0011] As a preferred technical solution of the present invention, in step S1, the temperature of the hot water is 85°C and the water consumption is 1 L / h.

[0012] As a preferred technical solution of the present invention, in step S2, the organic acid dispersant is one of formic acid, acetic acid, propionic acid, butyric acid, and isobutyric acid.

[0013] As a preferred technical solution of the present invention, in step S3, the drying temperature is 95-100° C. and the drying time is 30-60 min.

[0014] The invention discloses an application of an alkyl bisphosphonic acid composition, wherein the alkyl bisphosphonic acid composition can be applied to anti-corrosion treatment of metal surfaces.

[0015] Beneficial effects of the present invention: The present invention prepares a composition, which includes a bisphosphonic acid compound, phosphorous acid, phosphoric acid, alkyl phosphonic acid, dialkyl phosphonic acid and organic acid, and is prepared by hydrolyzing an alkyl bisphosphonic acid tetraester raw material. The method is simple and can be used to improve the corrosion resistance of metal surfaces. The present invention adds an organic acid after hydrolysis for dispersion and purification, using the principle of like dissolves like; and the organic acid, as a dispersant, interacts with the hydrolysis product through functional groups such as carboxyl groups in its molecular structure, thereby reducing the cohesive force between the hydrolysis product particles, so that the hydrolysis product forms smaller particles or a colloidal dispersion system in water, helping to increase the surface area of ​​the hydrolysis product and improving the purification efficiency.

[0016] Among them, bisphosphonic acid compounds usually have strong chelating ability and can form stable chelates with metal ions. This chelation not only enhances the chemical stability of the metal surface, but also forms a protective film on the metal surface, effectively isolating the corrosive medium, thereby improving the metal's corrosion resistance.

[0017] Phosphorous acid is a reducing acid that can slow down the corrosion process of metals by inhibiting the anodic reaction on the metal surface (such as the dissolution of metal ions). In addition, phosphorous acid can also react with the metal surface to form a dense phosphate film, which can prevent the corrosive medium from directly contacting the metal, further improving the corrosion resistance of the metal.

[0018] Phosphoric acid is a commonly used metal surface treatment agent. It can react with the metal surface to form a protective phosphating film or phosphate layer. This film can effectively prevent the metal from contacting with oxygen and moisture in the air, thereby playing a role in rust prevention. Phosphoric acid can also improve the performance of the metal surface and enhance its wear resistance and corrosion resistance.

[0019] Alkylphosphonic acid and dialkylphosphonic acid are phosphonic acid compounds containing alkyl chains. The presence of alkyl chains makes these compounds have better adsorption and film-forming properties on metal surfaces. They can form a hydrophobic protective film on the metal surface, effectively isolating the corrosive medium and improving the corrosion resistance of the metal. In addition, the length of the alkyl chain may also affect the density and stability of the protective film, thereby further affecting the corrosion resistance of the metal.

[0020] As a regulator, organic acids can improve the performance of the corrosive solution in a stable and balanced manner during the corrosion process, and play the role of a complexing buffer. They can form coordination bonds with metal ions to form a chelated ring structure containing metal ions, thereby enhancing the binding with the metal and improving the surface adhesion. In addition, the weak acidity of organic acids can also slow down the anisotropic corrosion of the corrosive solution and prevent local defects caused by uneven corrosion.

[0021] In the present invention, when the bisphosphonic acid compound is used as the main component and is combined with phosphorous acid, phosphoric acid, alkylphosphonic acid, dialkylphosphonic acid and organic acid, they can cooperate with each other to jointly improve the corrosion resistance of the metal surface, thereby forming a more stable and dense protective film on the metal surface, effectively improving the corrosion resistance. By depositing a self-assembled monolayer or a multilayer of organic phosphonate on the metal surface, the corrosion resistance of the metal is enhanced, and the metal corrosion is inhibited. DETAILED DESCRIPTION

[0022] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in combination with the embodiments.

[0023] The units of the purity and impurity content of the raw materials mentioned in the following examples are all mass percentages, and the units of the components in the obtained compositions are all mass percentages.

[0024] Example 1 The purity of the 1,12-dodecylbisphosphonic acid tetraethyl ester raw material used was 70%, and the impurities were 14.96% phosphite, 3.51% phosphate, and 11.46% ethyl phosphonate.

[0025] S1: adding 500 g of 1,12-dodecylbisphosphonic acid tetraethyl ester raw material into a reactor, continuously introducing water vapor into the reactor for hydrolysis for 8 h, and obtaining a crude product of 1,12-dodecylbisphosphonic acid composition after the hydrolysis is completed; S2: adding 1000 g of formic acid dropwise into the reaction kettle to disperse the crude product of the 1,12-dodecylbisphosphonic acid composition; S3: Then, the solid-liquid mixture consisting of the powdery dispersion product of the crude product of the 1,12-dodecylbisphosphonic acid composition and the organic acid was poured out and filtered, and the obtained product was placed in a drying oven at 95° C. for 30 minutes to obtain 340 g of 1,12-dodecylbisphosphonic acid composition 1.

[0026] The content of 1,12-dodecylbisphosphonic acid in composition 1 is 99.9%, and the content of formic acid is 0.1%.

[0027] Example 2 The purity of the 1,12-dodecylbisphosphonic acid tetraethyl ester raw material used is 80%, and the impurities are 6.3% phosphite, 3.5% phosphate, and 10.2% ethyl phosphonate.

[0028] S1: 300 g of 1,12-dodecylbisphosphonic acid tetraethyl ester raw material is added into a reactor, and hot water at 85° C. is continuously introduced into the reactor for hydrolysis for 6 h to obtain a crude product of 1,12-dodecylbisphosphonic acid composition, wherein the water consumption is 1 L / h; S2: After the hydrolysis is completed, 400 g of acetic acid is then added dropwise into the reaction kettle to disperse the crude product of the 1,12-dodecylbisphosphonic acid composition; S3: Then, the solid-liquid mixture consisting of the powdery dispersion product of the crude product of the 1,12-dodecylbisphosphonic acid composition and the organic acid is poured out and filtered, and the obtained product is placed in a drying oven at 95° C. for 40 minutes to obtain 235 g of 1,12-dodecylbisphosphonic acid composition 2.

[0029] The content of 1,12-dodecylbisphosphonic acid in composition 2 is 95.67%, the content of acetic acid is 1.5%, the content of ethylphosphonic acid is 2.32%, the content of phosphorous acid is 0.42%, and the content of phosphoric acid is 0.09%.

[0030] Example 3 The purity of the 1,12-dodecylbisphosphonic acid tetraethyl ester raw material used is 80%, and the impurities are 6.3% phosphite, 3.5% phosphate, and 10.2% ethyl phosphonate.

[0031] S1: adding 300 g of 1,12-dodecylbisphosphonic acid tetraethyl ester into a reactor, and continuously introducing water vapor into the reactor for hydrolysis for 12 h, and obtaining a crude product of 1,12-dodecylbisphosphonic acid composition after the hydrolysis is completed; S2: adding 400 g of propionic acid dropwise into the reaction kettle to disperse the crude product of the 1,12-dodecylbisphosphonic acid composition; S3: Then, the solid-liquid mixture consisting of the powdery dispersion product of the crude 1,12-dodecylbisphosphonic acid composition and the organic acid was poured out and filtered, and the obtained product was placed in a drying oven at 100° C. for 60 minutes to obtain 228 g of 1,12-dodecylbisphosphonic acid composition 3.

[0032] The content of 1,12-dodecylbisphosphonic acid in composition 3 is 98.03%, the content of propionic acid is 1%, and the content of ethylphosphonic acid is 0.97%.

[0033] Example 4 The purity of the 1,12-dodecylbisphosphonic acid tetraethyl ester raw material used was 83%, and the impurities were 3.3% phosphite, 3.0% phosphate, and 10.7% ethyl phosphonate.

[0034] S1: 300 g of 1,12-dodecylbisphosphonic acid tetraethyl ester raw material is added to a reactor, and water vapor is continuously introduced into the reactor for hydrolysis for 10 h, and a crude product of 1,12-dodecylbisphosphonic acid composition is obtained after the hydrolysis is completed; S2: adding 500 g of isobutyric acid dropwise into the reaction kettle to disperse the crude product of the 1,12-dodecylbisphosphonic acid composition; S3: Then, the solid-liquid mixture consisting of the powdery dispersion product of the crude product of the 1,12-dodecylbisphosphonic acid composition and the organic acid is poured out and filtered, and the obtained product is placed in a drying oven at 98° C. for 30 minutes to obtain 260 g of 1,12-dodecylbisphosphonic acid composition 4.

[0035] The content of 1,12-dodecylbisphosphonic acid in composition 4 is 94.97%, the content of isobutyric acid is 3%, and the content of ethylphosphonic acid is 2.03%.

[0036] Example 5 The purity of the methylenebisphosphonic acid tetraisopropyl ester raw material used was 90%, and the impurities were 5% phosphite, 4.0% phosphate, and 1.0% isopropyl phosphonate.

[0037] S1: 300 g of tetraisopropyl methylenebisphosphonate raw material is added to a reactor, and water vapor is continuously introduced into the reactor for hydrolysis for 10 h, and a crude product of a methylenebisphosphonic acid composition is obtained after the hydrolysis is completed; S2: adding 500 g of glacial acetic acid dropwise into the reaction kettle to disperse the crude product of the methylene bisphosphonic acid composition; S3: Then, the solid-liquid mixture consisting of the powdery dispersed product of the crude methylene bisphosphonic acid composition and the organic acid was poured out and filtered, and the obtained product was placed in a drying oven at 98° C. for 30 minutes to obtain 230 g of methylene bisphosphonic acid composition 5.

[0038] The content of methylenebisphosphonic acid in composition 5 is 98.1%, and the content of acetic acid is 1.9%.

[0039] Example 6 The purity of the 1,4-butylbisphosphonic acid tetraisopropyl ester raw material used was 88%, and the impurities were 7% phosphite, 4.0% phosphate, and 1.0% isopropyl phosphonate.

[0040] S1: 300 g of 1,4-butyl bisphosphonic acid tetraisopropyl ester raw material is added to a reactor, and water vapor is continuously introduced into the reactor for hydrolysis for 10 h, and a crude product of 1,4-butyl bisphosphonic acid composition is obtained after the hydrolysis is completed; S2: adding 600 g of glacial acetic acid dropwise into the reaction kettle to disperse the crude product of the 1,4-butylbisphosphonic acid composition; S3: Then, the solid-liquid mixture consisting of the powdery dispersion product of the crude product of the 1,4-butylbisphosphonic acid composition and the organic acid is poured out and filtered, and the obtained product is placed in a drying oven at 98° C. for 30 minutes to obtain 220 g of 1,4-butylbisphosphonic acid composition 6.

[0041] The content of 1,4-butylbisphosphonic acid in composition 6 is 99.1%, the content of acetic acid is 0.5%, and the content of phosphorous acid is 0.4%.

[0042] Example 7 The purity of the 1,16-hexadecylbisphosphonic acid tetraethyl ester raw material used was 85%, and the impurities were 4% phosphite, 1.0% phosphate, and 10.0% ethyl phosphonate.

[0043] S1: 300 g of 1,16-hexadecyl bisphosphonic acid tetraethyl ester raw material is added to a reactor, and water vapor is continuously introduced into the reactor for hydrolysis for 15 h, and a crude product of 1,16-hexadecyl bisphosphonic acid composition is obtained after the hydrolysis is completed; S2: adding 600 g of glacial acetic acid dropwise into the reaction kettle to disperse the crude product of the 1,16-hexadecyl bisphosphonic acid composition; S3: Then, the solid-liquid mixture consisting of the powdery dispersion product of the crude product of the 1,16-hexadecyl bisphosphonic acid composition and the organic acid is poured out and filtered, and the obtained product is placed in a drying oven at 98° C. for 30 minutes to obtain 220 g of 1,16-hexadecyl bisphosphonic acid composition 7.

[0044] The content of 1,16-hexadecylbisphosphonic acid in composition 7 is 99.0%, the content of acetic acid is 0.7%, and the content of phosphoric acid is 0.3%.

[0045] Application Example 1: The assembly conditions on the polished copper sample surface are: the concentration of the bisphosphonic acid composition 1 is c=0.1 g / L, the solvent is water and methanol in a volume ratio of 95:5, the assembly temperature T=30°C, the assembly time is t=1h, the curing temperature T=100°C, and the curing time t=30min.

[0046] Application Example 2: The assembly conditions on the polished aluminum sample surface are: concentration of bisphosphonic acid composition 1 c=0.5 g / L, solvent is water and methanol in a volume ratio of 80:20, assembly temperature T=30°C, assembly time t=0.5h, curing temperature T=120°C, and curing time t=20min.

[0047] Application Example 3: The assembly conditions on the polished iron sample surface are: concentration of bisphosphonic acid composition 1 c=0.5 g / L, solvent is water and methanol in a volume ratio of 80:20, assembly temperature T=30°C, assembly time t=1.0h, curing temperature T=120°C, and curing time t=20min.

[0048] Application Example 4: The assembly conditions on the polished zinc sample surface are: concentration of bisphosphonic acid composition 1 c=0.5 g / L, solvent is water and methanol in a volume ratio of 80:20, assembly temperature T=30°C, assembly time t=2h, curing temperature T=120°C, and curing time t=20min.

[0049] Comparative Examples 1-4: The polished metal sample was soaked in the bisphosphonic acid composition 1 at a concentration of c=0.5 g / L at room temperature for 1 hour, and then a sustained release test was performed.

[0050] Comparative Example 5 The 1,12-dodecylbisphosphonic acid used is a conventional bisphosphonic acid mixture, with a 1,12-dodecylbisphosphonic acid content of 90% and a chlorine content of 2000 ppm.

[0051] The assembly conditions on the polished copper sample surface were: conventional bisphosphonic acid mixture concentration c = 0.1 g / L, solvent was water and methanol in a volume ratio of 95:5, assembly temperature T = 30 ° C, assembly time t = 1 h, curing temperature T = 100 ° C, curing time t = 30 min.

[0052] Comparative Example 6 The 1,12-dodecylbisphosphonic acid used is a conventional bisphosphonic acid mixture, with a 1,12-dodecylbisphosphonic acid content of 90% and a chlorine content of 2000 ppm.

[0053] The assembly conditions on the polished aluminum sample surface were: conventional bisphosphonic acid mixture concentration c = 0.5 g / L, solvent was water and methanol in a volume ratio of 80:20, assembly temperature T = 30 ° C, assembly time t = 0.5 h, curing temperature T = 120 ° C, curing time t = 20 min.

[0054] Bisphosphonic acid composition 2 was assembled according to the conditions of application examples 1-4 to obtain application examples 5-8, bisphosphonic acid composition 3 was assembled according to the conditions of application examples 1-4 to obtain application examples 9-12, and bisphosphonic acid composition 4 was assembled according to the conditions of application examples 1-4 to obtain application examples 13-16. Comparative examples 1-4 corresponded to application examples 1-4, respectively, and no samples were assembled. Comparative examples 5-6 corresponded to application examples 1-2, respectively, and a traditional bisphosphonic acid mixture was used. The results are shown in the following table:

[0055] According to the above data, the data of the comparative examples are lower than those of the application examples, and the alkylbisphosphonic acid composition prepared by the present invention has an excellent effect of improving the corrosion resistance of metal surfaces.

[0056] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. An alkyl bisphosphonic acid composition, characterized in that: In terms of mass percentage, the alkylbisphosphonic acid composition comprises ≥90% of a bisphosphonic acid compound having structural formula I, 0-10% of phosphorous acid, 0-10% of phosphoric acid, 0-10% of alkylphosphonic acid, 0-10% of dialkylphosphonic acid, and 0-10% of organic acid; The structure of the bisphosphonic acid compound having structural formula I is: I， Wherein R is a straight chain or branched alkyl group with carbon atoms ranging from C1 to C20, and the branched chain is an alkyl group with carbon atoms ranging from C1 to C19.

2. A method for preparing and purifying the alkylbisphosphonic acid composition according to claim 1, characterized in that: The following steps are involved: S1, adding an alkyl bisphosphonic acid tetraester raw material containing impurities into a reactor, and continuously passing hot water or water vapor into the reactor for hydrolysis for 6 to 12 hours, and obtaining a crude product of an alkyl bisphosphonic acid composition after the hydrolysis is completed; S2, dropwise adding an organic acid dispersant in an amount of 1 to 10 times the mass of the crude product of the alkyl bisphosphonic acid into the reaction kettle, dispersing the crude product of the alkyl bisphosphonic acid composition to obtain a powdery dispersion; S3. Then, the powdered dispersed product and the organic acid are poured out and filtered, and the obtained product is placed in a drying oven and dried to obtain the alkyl bisphosphonic acid composition.

3. The method for preparing and purifying the alkylbisphosphonic acid composition according to claim 2, characterized in that: In step S1, the structure of the alkyl bisphosphonate tetraester raw material is a linear or branched alkyl bisphosphonate with a carbon number of C1 to C20, wherein the branch contains an alkyl group with a carbon number of C1 to C19, and the ester group is a linear or branched alkyl ester with a carbon number of C1 to C20.

4. The method for preparing and purifying the alkylbisphosphonic acid composition according to claim 2, characterized in that: In step S1, the impurities are phosphites and phosphonate substances, including phosphite diesters, phosphite triesters, alkyl phosphonate diesters, dialkyl phosphonates, and phosphate triesters, wherein the alkyl group in the impurities is a straight-chain or branched alkyl group with a carbon number of C1 to C20, and the ester group in the impurities is a straight-chain or branched alkyl ester with a carbon number of C1 to C20.

5. The method for preparing and purifying the alkylbisphosphonic acid composition according to claim 2, characterized in that: In step S1, the content of impurities in the alkyl bisphosphonate tetraester raw material is in the following mass percentage ranges: phosphite diester is 0-15%, phosphite triester is 0-25%, alkyl phosphonic acid diester is 0-25%, dialkyl phosphonate is 0-10%, and phosphate triester is 0-15%.

6. The method for preparing and purifying the alkylbisphosphonic acid composition according to claim 2, characterized in that: In step S1, the temperature of the hot water is 85°C, and the water consumption is 1 L / h.

7. The method for preparing and purifying the alkylbisphosphonic acid composition according to claim 2, characterized in that: In step S2, the organic acid dispersant is one of formic acid, acetic acid, propionic acid, butyric acid, and isobutyric acid.

8. The method for preparing and purifying the alkylbisphosphonic acid composition according to claim 2, characterized in that: In step S3, the drying temperature is 95-100° C. and the drying time is 30-60 min.

9. Use of the alkylbisphosphonic acid composition according to any one of claims 1 to 8, characterized in that: The alkylbisphosphonic acid composition can be used for anti-corrosion treatment of metal surfaces.

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