High-activity and high-stability vanadium iso-octoate and preparation method thereof

Abstract

This invention discloses a highly active and stable vanadium isooctanoate and its preparation method, comprising the following steps: S1, in a reactor, vanadium metal powder, isooctanoic acid, and an iron-based catalyst are mixed, heated, and an aqueous solution of tert-butyl hydrogen peroxide is added to carry out an oxidation reaction; S2, after the oxidation reaction is completed, ferric isooctanoate is added to the reaction system to carry out a valence state control reaction; S3, post-treatment is performed to obtain a vanadium isooctanoate solution. This invention uses tert-butyl hydrogen peroxide as an oxidant and an iron compound as a catalyst to oxidize vanadium metal powder to V... 3+ At the same time, a small amount of ferric isooctanoate (III) is added to further improve the activity of vanadium isooctanoate and greatly improve production efficiency; ferric isooctanoate (III) is reduced to ferrous isooctanoate (II), which improves the stability of vanadium isooctanoate. The vanadium-iron compound can further improve product performance, and isoascorbic acid stabilizer is added to prevent performance degradation and precipitation of vanadium isooctanoate during storage.

Description

Technical Field

[0001] This invention belongs to the field of organometallic salt synthesis technology, specifically relating to vanadium isooctanoate and its preparation method, and particularly to a method for preparing a highly active and highly stable vanadium isooctanoate solution with vanadium-iron synergistic effect by catalytic oxidation of vanadium metal powder. Background Technology

[0002] Cobalt salts of organic acids are widely used as catalysts in resin accelerators and paint drying. However, due to the high price of cobalt, current products on the market are designed to reduce the amount of cobalt salt used to lower product costs. Vanadium salts of organic acids, as the most ideal substitute for cobalt salts, have a catalytic effect ten times that of cobalt salts and have long been favored by researchers.

[0003] Vanadium isooctanoate is an oil-soluble, green, viscous liquid, commonly used as a paint drying agent and an unsaturated resin curing accelerator. Existing synthetic routes for vanadium isooctanoate include reduction-metathesis / direct esterification, high-temperature acylation, and vanadium tetrachloride synthesis.

[0004] Vanadium isooctanoate prepared by the "oxidation-reduction method" of vanadium pentoxide obtained by high-temperature calcination of ammonium metavanadate and hydrazine isooctanoate has poor stability, is prone to stratification and precipitation, and has a shelf life of up to 30 days. Because of the precipitation, water and material are not separated, so filtration is required during preparation, making the operation extremely complicated. The yield is low, generally between 70% and 85%, and the cost is high.

[0005] Patent document CN103058847A improved the "oxidation-reduction method". First, isooctanoic acid and hydrazine hydrate (reducing agent) are added to the reaction vessel. The mixture is heated to 35-45°C, and then solvent (200# solvent gasoline) and propionic acid are added. When the temperature reaches 45-55°C, vanadium pentoxide and an extractant are added. The reaction is carried out under nitrogen protection with heating and stirring. When the temperature reaches 65-70°C, the reaction is maintained at a constant temperature for 2-4 hours (during which V is reduced). 5+ Transform into V 3+ The reaction was stopped, a small amount of isooctanoic acid + KOH was added, water was removed, the mixture was cooled and filtered, and the solvent was diluted to obtain the final product. The vanadium isooctanoate prepared in this literature exhibits good stability and a dark green appearance, making it suitable for use as an accelerator and paint drying agent, achieving an ideal replacement for cobalt salts. However, this method uses hydrazine hydrate as a reducing agent, and under nitrogen protection, V... 5+ Transform into V 3+ Then it reacts with isooctanoic acid, and hydrazine hydrate is a controlled chemical, which increases the company's compliance costs and security pressure; the process is complex and requires strict nitrogen protection, which increases equipment investment and operation difficulty.

[0006] A high-temperature acylation method can be exemplified by patent document CN116854583A, which discloses an oil-soluble vanadium isooctanoate material and its preparation method. The preparation method includes the following steps: a vanadium-containing compound, acetic anhydride, and isooctanoic acid undergo a first reaction to obtain a reaction mixture; the reaction mixture is then subjected to rotary evaporation to remove water, acetic acid, and acetic anhydride from the system, followed by the addition of isooctanoic acid to obtain the oil-soluble vanadium isooctanoate material; wherein, during the first reaction, the weight ratio of the vanadium-containing compound, acetic anhydride, and isooctanoic acid is 1:(2-10):(3-30). This document describes a simple and safe preparation process, complete miscibility with oil, and a final product with good stability and long-term storage capability. However, this method uses the controlled chemical acetic anhydride, whose purchase, transportation, and use are strictly regulated; furthermore, the reaction temperature needs to be as high as 155-185℃, and rotary evaporation is required to remove acetic acid and acetic anhydride, resulting in high energy consumption.

[0007] Patent document CN108440276A discloses an organic carboxylic acid vanadium salt and its preparation method using the vanadium tetrachloride method. In this method, an organic carboxylic acid (isooctanoic acid) is slowly added dropwise to vanadium tetrachloride (VCl4) in an anhydrous apparatus, and the mixture is reacted at 60°C under N2 protection. The hydrogen chloride produced during the reaction is removed by heating and reducing pressure to obtain a liquid organic carboxylic acid vanadium salt. However, the VCl4 produced in this method rapidly hydrolyzes upon contact with water or water vapor in the air, producing highly toxic and corrosive hydrogen chloride gas (HCl). This places extremely high demands on equipment sealing, exhaust gas treatment systems, and operator safety, resulting in significant environmental pressure. Moreover, the cost of VCl4 is much higher than that of vanadium pentoxide or metallic vanadium powder, leading to a lack of economic competitiveness for the product.

[0008] Other literature reports the use of vanadium powder + isooctanoic acid, with O2 introduced to reduce V. 0 Oxidized to V 3+ However, the oxidation process is slow, and even after 24 hours of reaction, a large amount of vanadium powder remains unoxidized.

[0009] Therefore, developing a new method for preparing vanadium isooctanoate with readily available and safe raw materials, mild reaction conditions, and excellent and stable product performance is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0010] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method for preparing vanadium isooctanoate that has convenient raw material sources, rapid and efficient reaction, and products with both high activity and high stability.

[0011] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for preparing highly active and stable vanadium isooctanoate includes the following steps: S1, Oxidation reaction: In an inert organic solvent, vanadium powder, isooctanoic acid, and an iron-based catalyst are added, and the mixture is heated to a reaction temperature of 60–120°C with stirring. A tert-butyl hydrogen peroxide aqueous solution is slowly added dropwise to carry out the oxidation reaction. The iron-based catalyst is one or more of anhydrous ferrous ammonium sulfate, ferric ammonium ethylenediaminetetraacetate (EDTA ferric ammonium, CAS No.: 21265-50-9), and ferric acetylacetone (CAS No.: 14024-18-1). The molar ratio of vanadium powder, isooctanoic acid, tert-butyl hydrogen peroxide, and the iron-based catalyst is 1.0: (3.0–6.0): (1.5–3.5): (0.01–0.10). S2, Valence Adjustment: After the vanadium powder in step S1 has completely dissolved, add a small amount of ferric isooctanoate (III, CAS No. 7321-53-1) to the system and continue the reaction for a period of time to partially dissolve the vanadium. 3+ Oxidized to V 4+ At the same time, ferrous isooctanoate is reduced to ferrous isooctanoate (II). S3, Post-treatment: After dehydration, a stabilizer is added to the system to obtain a dark green vanadium isooctanoate solution.

[0012] Preferably, in step S1, the vanadium metal powder has a purity of 99% or higher and a particle size of 100-500 mesh; the inert organic solvent is isooctanoic acid (the reactant itself acts as a solvent), 1500# solvent oil, 1800# solvent oil, or / and 200# solvent oil.

[0013] Preferably, the molar ratio of each main raw material in step S1 is: vanadium metal powder: isooctanoic acid: tert-butyl hydroperoxide: iron catalyst = 1.0: (3.0~6.0): (1.5~3.5): (0.01~0.10).

[0014] Preferably, in step S1, the reaction temperature is 80-100℃ and the total reaction time is 2-8h.

[0015] Preferably, in step S2, the amount of iron isooctanoate (III) added is 0.5% to 2.0% of the initial molar amount of vanadium metal powder.

[0016] Preferably, in step S3, the stabilizer is isoascorbic acid (CAS No. 89-65-6) or sodium isoascorbate (CAS No. 6381-77-7); the amount of stabilizer added is 0.1% to 2.0% of the initial vanadium metal powder mass.

[0017] Preferably, in step S3, the dehydration is one or more of the following: static phase separation, vacuum distillation, and centrifugal separation.

[0018] The preparation method is carried out in a conventional reactor without the need for nitrogen protection.

[0019] This invention also provides a vanadium isooctanoate solution prepared by the aforementioned method for preparing highly active and stable vanadium isooctanoate, which contains trivalent (V... 3+ ) and tetravalent vanadium (V 4+ Vanadium isooctanoate and ferrous isooctanoate (Fe) 2+ A homogeneous liquid complex.

[0020] The present invention also provides the application of the vanadium isooctanoate solution as a coating drying agent or an unsaturated resin curing accelerator.

[0021] The reaction principle of this invention is as follows: using tert-butyl hydroperoxide as the oxidant and an iron-based catalyst (such as anhydrous ferrous ammonium sulfate) as the selective catalyst, vanadium metal powder is oxidized to V. 3+ Add a small amount of ferrous isooctanoate (Fe 3+ As a co-catalyst, it promotes the partial removal of V by residual tert-butyl hydrogen peroxide in the system. 3+ Further oxidation to V 4+ Ultimately, V was obtained. 3+ / V 4+ Vanadium isooctanoate in mixed valence states; and Fe in iron isooctanoate. 3+ Reduced to ferrous ions (Fe) 2+ This process generates ferrous isooctanoate, which has a synergistic drying effect. Ferrous isooctanoate can improve the stability of vanadium isooctanoate and can also be used as a paint drying agent and an unsaturated resin curing accelerator. The synergistic effect of vanadium and ferric oxide can further improve product performance. The addition of isoascorbic acid in the later stage of the reaction removes excess tert-butyl hydroperoxide, which can prevent vanadium isooctanoate from being oxidized to V during storage. 5+ This leads to performance degradation and precipitation.

[0022] Compared with the prior art, the present invention has the following advantages: (1) In this invention, vanadium metal powder is used instead of vanadium pentoxide or VCl4 as the vanadium source, and tert-butyl hydroperoxide is used instead of hydrazine hydrate or acetic anhydride as the core reagent of the oxidation / reduction system. Selective iron-based catalysts with ligands are used as electron transfer media. Iron ions regulate the reaction process by changing the oxidation state, and together they achieve the oxidation conversion of vanadium metal, promoting the conversion of VCl4 by TBHP. 0 Oxidized to V 3+ This fundamentally avoids the use of easily explosive chemicals, and the raw materials are more readily available and safer.

[0023] The system of this invention contains isooctanoic acid (pKa about 5), which is weakly acidic and helps to inhibit the self-decomposition of TBHP; the reaction temperature is controlled at 60-120°C, and the "droplet addition method" controls the exothermic reaction, avoiding the risk of violent decomposition or explosion; the reaction medium is an inert organic solvent (1500# oil, 200# oil) with low water content, which further reduces the aqueous side reactions initiated by free radicals.

[0024] (2) In this invention, ferric isooctanoate is introduced to promote the reaction and regulate the valence state of vanadium, thereby obtaining vanadium V containing isooctanoate. 3+ / V 4+ The mixture, with vanadium in different valence states having different catalytic activity windows, synergistically improved the overall drying / promoting effect of the product; simultaneously, the in-situ generated ferrous isooctanoate (Fe) 2+ Ferrous isooctanoate itself is also a drying agent, forming a vanadium-iron complex synergistic system with vanadium isooctanoate, exhibiting significantly better catalytic activity than a single component; thus improving the drying activity and stability of the product. This is an innovative formulation of the present invention. Both ferrous isooctanoate and isoascorbic acid are excellent antioxidants and stabilizers, effectively preventing high-valent vanadium (V... 5+ The generation of this product solves the problems of traditional products being prone to stratification, sedimentation, and deterioration, and the product shelf life can reach more than one year.

[0025] (3) This invention overcomes the technical problem of slow reaction rate of direct oxidation of vanadium metal powder (traditional method > 24h). By accelerating the oxidation process with iron-based catalysts (such as ferrous ammonium sulfate), the reaction time is shortened to 2-6h, which greatly improves production efficiency.

[0026] (4) The raw materials of the present invention are all ordinary industrial products, which are not highly toxic or corrosive. The procurement, storage and use process is safe, compliant and convenient. No highly corrosive gases such as HCl are generated during the reaction process, and the process safety is significantly improved. No expensive anhydrous reaction device and complex HCl tail gas absorption system (such as lime water absorption tower) are required, which reduces equipment investment and waste treatment costs. Detailed Implementation

[0027] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Example 1 A method for preparing highly active and stable vanadium isooctanoate includes the following steps: S1, add 10.2g (0.2mol) of vanadium metal powder, 88g (0.61mol) of isooctanoic acid, 1g (0.0035mol) of anhydrous ferrous ammonium sulfate, and 100g of 1500# solvent oil to a 500mL four-necked flask equipped with a stirrer, thermometer, condenser, and dropping funnel. Turn on the stirrer and heat to 80℃. Slowly add 43g (approximately 0.334mol) of C4H4O through the dropping funnel. 10The oxidation reaction was carried out using 70% tert-butyl hydrogen peroxide aqueous solution (O2), with the addition time controlled at about 2 hours. The system was exothermic during the addition process, and the reaction temperature was maintained at 90-95℃. After the addition was completed, the reaction was kept at the temperature for another 2 hours to confirm that the vanadium metal powder was completely dissolved, resulting in a dark green transparent liquid. S2, 0.9 g of ferric isooctanoate (Fe) was added to the system. 3+ (0.00185 mol), and continue the reaction at 90℃ for 1.5 h, to partially convert V 3+ Oxidized to V 4+ At the same time, ferrous isooctanoate is reduced to ferrous isooctanoate; S3, gradually heat to 105℃, and distill under reduced pressure at -0.090MPa for 35min to distill off the water in the system; cool to 80℃, add 0.012g isoascorbic acid, and stir for 30min; test the vanadium content of the reaction product = 4.43%, and add 24.8g of 1500# solvent oil; S4. Centrifugation removes any trace amounts of insoluble impurities that may be present, yielding a dark green vanadium isooctanoate solution with a vanadium content of approximately 4.0%.

[0029] The method for determining the vanadium content is as follows: accurately weigh 1.0g of the sample to be tested, heat and carbonize it on an electric furnace, transfer it to a muffle furnace and ashing it at 550℃ to constant weight, dissolve the residue with dilute sulfuric acid, and determine the mass percentage content of vanadium by inductively coupled plasma atomic emission spectrometry.

[0030] Example 2 A method for preparing highly active and stable vanadium isooctanoate includes the following steps: S1, in a stainless steel reactor equipped with a stirrer, thermometer, and condenser, add 51 kg (1000 mol) of metallic vanadium powder, 576.8 kg (4000 mol) of isooctanoic acid, and 25 kg (approximately 69 mol) of EDTA iron ammonium; start stirring and jacket steam heating, raising the temperature to 70°C; then, using a metering pump, uniformly pump in 386 kg (approximately 3000 mol) of C4H4O2 over 3 hours. 10 The oxidation reaction was carried out with 70% tert-butyl hydrogen peroxide (O2), and the reaction temperature was controlled at 95-100℃. After the addition was complete, the reaction was continued at this temperature for 3.5 hours. Samples were taken for observation to confirm that the vanadium powder was completely dissolved, and a dark green transparent liquid was obtained. S2, 9 kg of ferric isooctanoate (Fe) was added to the system. 3+ (18.54 mol), continue the reaction at 95℃ for 2 hours, and part of V 3+ Oxidized to V 4+ At the same time, ferrous isooctanoate is reduced to ferrous isooctanoate; S3, gradually heat to 110℃, and distill under reduced pressure at -0.090MPa for 60min to remove water from the system; cool to 70℃, add 0.8kg isoascorbic acid, and stir for 30min; test the vanadium content of the reaction product = 5.60%, and add 368kg of 1500# solvent oil; S4, centrifugation removes any trace amounts of insoluble impurities, yielding a dark green vanadium isooctanoate solution with a vanadium content of approximately 4.0%.

[0031] Example 3 A method for preparing highly active and stable vanadium isooctanoate includes the following steps: S1, add 10.2g (0.2mol) vanadium powder, 173g (1.2mol) isooctanoic acid, 3.53g (0.01mol) ferric acetylacetone and 30g 200# solvent oil to a 1000mL four-necked flask equipped with a stirrer, thermometer, condenser and dropping funnel, start stirring and heat to 70℃; slowly add 50g (about 0.388mol) of C4H through the dropping funnel. 10 The oxidation reaction was carried out using 70% tert-butyl hydrogen peroxide aqueous solution (O2), with the addition time controlled at about 2 hours. The system was exothermic during the addition process, and the reaction temperature was maintained at 90-95℃. After the addition was completed, the reaction was kept at the temperature for another 6 hours to confirm that the vanadium powder was completely dissolved, resulting in a dark green transparent liquid. S2, 1.2g of ferric isooctanoate (Fe) was added to the system. 3+ (0.00247 mol), and continue the reaction at 95℃ for 1.5 h, to partially convert V 3+ Oxidized to V 4+ At the same time, ferrous isooctanoate is reduced to ferrous isooctanoate; S3, gradually heat to 108℃, and distill under reduced pressure at -0.090MPa for 45min to remove water from the system; cool to 70℃, add 0.02g isoascorbic acid, and stir for 30min; test the vanadium content of the reaction product = 4.03%, and add 2.1g of 200# solvent oil; S4, centrifugation removes any trace amounts of insoluble impurities, yielding a dark green vanadium isooctanoate solution with a vanadium content of 4.0%.

[0032] Comparative Example 1: No catalyst S1, add 10.2g (0.2mol) of vanadium powder, 88g (0.61mol) of isooctanoic acid, and 100g of 1500# solvent oil to a 500mL four-necked flask equipped with a stirrer, thermometer, condenser, and dropping funnel. Turn on the stirrer and heat to 80℃; slowly add 43g (approximately 0.334mol) of C4H4O through the dropping funnel. 10The oxidation reaction was carried out using 70% tert-butyl hydrogen peroxide aqueous solution (O2), with the addition time controlled at about 2 hours. The system was exothermic during the addition process, and the reaction temperature was maintained at 90-95℃. After the addition was completed, the reaction was kept at the temperature for another 16 hours to confirm that the vanadium powder was completely dissolved, resulting in a dark green transparent liquid. S2, 0.9 g of ferric isooctanoate (Fe) was added to the system. 3+ (0.00185 mol), and continue the reaction at 90℃ for 1.5 h, to partially convert V 3+ Oxidized to V 4+ At the same time, ferrous isooctanoate is reduced to ferrous isooctanoate; S3, gradually heated to 105℃ and distilled under reduced pressure at -0.090MPa for 1h to remove water from the system; cooled to 80℃, added 0.01g of isoascorbic acid, and stirred for 30min; tested the vanadium content of the reaction product to be 4.45%, and added 25.8g of 1500# solvent oil; S4, centrifugation removes any trace amounts of insoluble impurities, yielding a dark green vanadium isooctanoate solution with a vanadium content of 4.0%.

[0033] Comparative Example 2 Compared with Example 1, Comparative Example 2 omits step S2 and does not add ferric isooctanoate (III) for oxidation; the remaining steps are the same as in Example 1; after dehydration, an appropriate amount of 1500# solvent oil is added to obtain a dark green vanadium isooctanoate solution with a vanadium content of 4%.

[0034] Comparative Example 3 Compared with Example 1, step S2 of Comparative Example 3 is: adding 0.65g of ferric isooctanoate (Fe) to the system. 2+ (CAS No. 93920-15-1, 0.0019 mol), and continued the reaction at 90℃ for 1.5 h; the remaining raw materials and processes were the same as in Example 1. After dehydration, an appropriate amount of 1500# solvent oil was added, and after centrifugation, a dark green vanadium isooctanoate solution with a vanadium content of 4.05% was obtained.

[0035] Comparative Example 4 Vanadium isooctanoate was prepared using the method described in Example 1 of patent document CN103058847A. The product was a dark green liquid, but after being left at room temperature for about 25 days, a noticeable black precipitate appeared at the bottom of the bottle, and the liquid color lightened, indicating that the product had deteriorated.

[0036] Experimental test case The vanadium isooctanoate obtained in Examples 1-3 and Comparative Examples 1-4 were tested.

[0037] As can be seen from the reaction times of Examples 1-3, the addition of iron-based catalysts can significantly shorten the reaction time, with anhydrous ferrous ammonium sulfate showing the best catalytic effect.

[0038] 1. Take 100g each of the vanadium isooctanoate solution from Examples 1-3, Comparative Examples 1-4, and commercially available vanadium isooctanoate solution (4% vanadium isooctanoate from Shanghai Taoyuan Cobalt Co., Ltd.), place them in a 50℃ oven, and observe the appearance of the samples periodically. If precipitation occurs, it indicates abnormal stability. The experiment is conducted in 3-month cycles, as shown in Table 1.

[0039] Table 1. Stability test results of Examples 1-3 and Comparative Examples 1-4 Experimental data show that the vanadium isooctanoate solution in Example 1 has excellent stability. In Comparative Example 1, iron isooctanoate (III) was not added, and the stability decreased because the system did not contain iron isooctanoate (II).

[0040] 2. Add 0.4% of commercially available vanadium isooctanoate solution, vanadium isooctanoate solution of Examples 1-3 and Comparative Examples 1-4 to the Yabang 191 unsaturated polyester resin sample, and then add 0.8% of methyl ethyl ketone peroxide. Test the gel time, curing time and peak value of the reaction exotherm. The results are shown in Table 2.

[0041] Table 2 Performance test results of Examples 1-3 and Comparative Examples 1-4 Experimental data show that the vanadium isooctanoate solutions in Examples 1-3 have a system of V 3+ and V 4+ The mixture contains vanadium and ferrometallic metals, which are blended in a certain proportion to significantly improve the product's performance.

[0042] Comparative Example 1, without a catalyst, had an excessively long reaction time, but the product performance showed no significant change. Comparative Example 2, without the addition of ferric isooctanoate (III), had performance comparable to commercially available products and Comparative Example 4. Comparative Example 3, with the addition of ferric isooctanoate (II), showed no oxidizing properties; it was merely a mixture of ferrovanadium and ferrovanadium in a specific ratio, and the system lacked V... 4+ Its performance is worse than that of Comparative Example 1, but better than that of Comparative Example 2.

Claims

1. A method for preparing highly active and highly stable vanadium isooctanoate, characterized in that, Includes the following steps: S1, in an inert organic solvent, vanadium powder, isooctanoic acid, and an iron-based catalyst are added, and the mixture is heated to a reaction temperature of 60–120°C with stirring; tert-butyl hydrogen peroxide aqueous solution is slowly added dropwise to carry out the oxidation reaction; the iron-based catalyst is one or more of anhydrous ferrous ammonium sulfate, ferric ammonium ethylenediaminetetraacetate, and ferric acetylacetone; the molar ratio of vanadium powder, isooctanoic acid, tert-butyl hydrogen peroxide, and iron-based catalyst is 1.0:(3.0–6.0):(1.5–3.5):(0.01–0.10); S2, after the vanadium powder in step S1 has completely dissolved, add a small amount of ferric isooctanoate to the system and continue the reaction for a period of time to remove some of the V. 3+ Oxidized to V 4+ At the same time, ferrous isooctanoate is reduced to ferrous isooctanoate; S3, after dehydration, a stabilizer is added to the system to obtain a dark green vanadium isooctanoate solution.

2. The method for preparing vanadium isooctanoate according to claim 1, characterized in that, In step S1, the vanadium metal powder has a purity of 99% or higher and a particle size of 100-500 mesh; the inert organic solvent is isooctanoic acid, 1500# solvent oil, 1800# solvent oil, or / and 200# solvent oil.

3. The method for preparing vanadium isooctanoate according to claim 1, characterized in that, In step S1, the reaction temperature is 80–100℃ and the total reaction time is 2–8 hours.

4. The method for preparing vanadium isooctanoate according to claim 1, characterized in that, In step S2, the amount of iron isooctanoate added is 0.5% to 2.0% of the initial molar amount of vanadium metal powder.

5. The method for preparing vanadium isooctanoate according to claim 1, characterized in that, In step S3, the stabilizer is isoascorbic acid or sodium isoascorbate; the amount of stabilizer added is 0.1% to 2.0% of the initial mass of vanadium metal powder.

6. The method for preparing vanadium isooctanoate according to claim 1, characterized in that, In step S3, the dehydration is one or more of the following: static phase separation, vacuum distillation, and centrifugal separation.

7. The vanadium isooctanoate solution prepared by any one of the methods for preparing highly active and stable vanadium isooctanoate according to claims 1 to 6 is a homogeneous liquid complex of vanadium isooctanoate containing trivalent and tetravalent vanadium and ferrous isooctanoate.

8. The application of the vanadium isooctanoate solution according to claim 1, characterized in that, As a paint drying agent or an unsaturated resin curing accelerator.

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