Transparent bordeaux mixture and preparation method thereof by means of micellar reaction

Abstract

A transparent Bordeaux mixture, which is a basic copper sulfate "water-in-oil" nano-emulsion, where the basic copper sulfate particles are located in "water-in-oil" nano-solubilizing micelle bundles. Same falls under types of pesticides that are insoluble in water and solvents, and the particles are less than 100 nm in size, and are particularly a nanometer suspension dispersion liquid less than 50 nm in size.

Description

Transparent Bordeaux mixture and preparation method thereof through micellar reaction

Technical field

[0001] The present invention belongs to the field of nano pesticides, and particularly relates to the preparation of a dispersion of particles insoluble in water and organic solvents with a size of less than 100 nanometers, especially less than 50 nanometers. [Background Technology]

[0002] Modern agricultural production requires the use of pesticides. Improving the formulation performance of existing pesticides, increasing their efficacy, reducing their dosage, and mitigating their impact on the environment are of great significance to the sustainable development of agricultural production.

[0003] An effective way to achieve pesticide reduction is to effectively reduce the particle size of the active ingredients in pesticide formulations. For water-insoluble pesticides, the minimum size is a few nanometers. Nanopesticides refer to formulations in which the pesticide particles are at the nanometer scale (1 to 100 nm). The particle size of traditional pesticide formulations is on the micrometer scale, ranging from a few microns to tens of microns or even larger. If the particle size is reduced to nanometers, the size is reduced by a thousand times, and the number of particles can theoretically increase by a billion times, and the surface area can increase by a thousand times. The dramatic increase in the number and surface area of ​​pesticide particles can be more evenly dispersed on crop leaves, making contact with the target more extensive, and the efficacy of the drug can be more fully exerted and improved.

[0004] On April 1, 2019, the International Union of Pure and Applied Chemistry (IUPAC), celebrating its 100th anniversary, announced its "Top 10 Chemical Inventions That Will Change the World," with nanopesticides topping the list. This is due to the growing global population, projected to approach 10 billion by 2050. Feeding this large population requires a significant increase in agricultural output while minimizing the environmental impact of land use, including reducing pesticide pollution and water consumption. Nanopesticides, with their small particle size and improved target absorption, offer a promising tool for addressing the key challenges of traditional pesticides: environmental pollution, pesticide accumulation in organisms, and the significant increase in pest and disease resistance. While nanopesticides are by no means the only path to sustainable agricultural development, they certainly offer a lower impact on the environment and human health, contributing to a more sustainable future for the planet.

[0005] Bordeaux mixture is a typical inorganic compound pesticide. Over the past century, it has played a significant role in controlling a variety of fungal diseases in plants. It contains no harmful impurities, is less susceptible to pesticide damage, is rain-resistant, and lacks resistance. It can be used in combination with certain other pesticides and remains a widely used broad-spectrum, protective fungicide. The active ingredient in Bordeaux mixture is basic copper sulfate, but its solubility in water is extremely low, at only 1.06 mg / L. Furthermore, one of the common raw materials used in its preparation is calcium hydroxide, which is also poorly water-soluble, resulting in a light blue, viscous suspension. For ease of use, companies prepare basic copper sulfate as a solid and process it into formulations, primarily wettable powders, with a smaller amount of suspension concentrates. The particle size of these formulations ranges from tens to tens of microns. As with other traditional pesticide formulations, the large particle size limits Bordeaux mixture's efficacy and also results in a higher dosage per unit area.

[0006] Bordeaux mixture is an ancient and widely used agricultural fungicide, primarily composed of a mixture of copper sulfate, slaked lime (calcium hydroxide), and water. This mixture is particularly effective in preventing and controlling fungal infections on plants such as grapevines, potatoes, peaches, apples, and bananas. Despite its importance in organic farming, Bordeaux mixture's use has raised some environmental concerns. The long-term, large-scale application of copper-containing preparations is bound to have ecological impacts and harm. In particular, the accumulation of copper, its primary component, can lead to soil and water contamination and potential toxicity to ecosystem organisms such as fish and earthworms.

[0007] High concentrations of copper are used to control fungal and bacterial plant diseases. It is the only product capable of controlling downy mildew caused by the fungus Fischer-Ribes. At lower concentrations, copper is an essential trace nutrient for plants and animals. Most crops require copper as a micronutrient, and the dosage is substantial. For crops grown in acidic organic soils, application concentrations range from 3.4 to 6.7 kg / hectare or 2.0 to 3.4 kg / hectare, respectively. For faster onset, foliar sprays of 8 g / L of copper ion are also used. The continued and extensive use of copper preparations for plant disease control and as a nutrient inevitably pollutes the environment and affects plant and animal health. Developed countries worldwide are currently working to reduce the use of copper-containing preparations. European Commission Regulation (EC) 889 / 2008 stipulates copper dosages for organic agriculture, recommending a maximum of 1 kg / hectare per treatment, with a maximum limit of 6 kg / hectare / year. Further work is underway to reduce the maximum permissible copper concentration. A survey conducted in 12 European countries showed that the annual use of copper in organic agriculture was 3,258 tons, which is 52% of the permitted annual dosage. While this has not yet been put on the agenda in my country, the trend suggests that reducing the use of copper preparations is imperative globally.

[0008] Europe is deeply concerned about the environmental impacts of the copper content of Bordeaux mixture, particularly its accumulation in soil and its long-term environmental impacts. Because copper ions can bioaccumulate, most EU countries have banned the use of Bordeaux mixture. Only a few countries, including Belgium, Cyprus, France, Greece, Hungary, Italy, Malta, Portugal, Romania, and Slovenia, still allow its use.

[0009] Reducing the particle size of copper-containing formulations, thereby improving efficacy and reducing dosage, is undoubtedly an effective approach to addressing the global copper pollution problem. For over a century, Bordeaux mixture, a traditional and widely used pesticide with protective properties, was largely unappreciated, as its particle size impacted control effectiveness and increased dosage. With increasing understanding of pesticide formulations and advancements in innovative technology, the development of clear, transparent Bordeaux mixture at sprayable concentrations (with particle sizes as small as 100nm, and particularly 50nm) has become a pressing issue.

[0010] No data were found on the preparation of nanoscale Bordeaux mixture. Nanotechnology can be used to prepare copper preparations to improve the efficiency of Bordeaux mixture, reduce dosage, and reduce environmental impact. The preparation of nanoparticles typically involves reducing copper or its compounds to nanoscale. Such particles may have higher biological activity and better utilization due to their increased surface area, and have been shown to improve the environmental friendliness of Bordeaux mixture and enhance its antifungal efficacy.

[0011] In summary, Bordeaux mixture is an effective agricultural fungicide and nutrient, but its use is subject to certain restrictions due to environmental concerns. This further necessitates the application of nanotechnology to improve its efficiency, reduce dosage, and minimize environmental impact. This present invention explores the feasibility and effectiveness of these approaches. Existing technology:

[0012] 1. “Study on the preparation of nano basic copper sulfate fungicide by uniform precipitation method” (Yi Qiushi, Pesticides, 2001, 40(8):20-22)

[0013] The technical solution disclosed in this article cannot produce basic copper sulfate at the strict nanoscale. The article claims that "nanoparticle basic copper sulfate" is produced by chemically controlling the particle size by reacting copper sulfate with ammonia and heating it. However, no particle size data is provided, and the scale in the electron microscope photograph of the aggregated particles is unrecognizable. It also states that "the prepared nanoparticle basic copper sulfate, when mixed with water containing a small amount of dispersant at a concentration of 1-5‰, is highly dispersed into a nearly translucent state." Based on the appearance of the basic copper sulfate dispersion produced by this technology, common sense in colloidal solutions suggests that the particle size should be over several hundred nanometers, approaching or exceeding micrometers.

[0014] 2. "Preparation and Mechanism of Nano-Basic Copper Sulfate Suspension Agent" (Gao Mengmeng, Master's Thesis, Shenyang Agricultural University, 2021)

[0015] The technical solution published in this master's thesis also fails to produce basic copper sulfate at the strict nanoscale. The thesis states that a 40% nano basic copper sulfate suspension was prepared using commercially available "nano basic copper sulfate" powder (particle size not specified) by selecting several additives and grinding process conditions. However, the particle size of the basic copper sulfate in the prepared sample was not given. The size data measured for the ground sample is as follows: 50 The particle size distribution of the copper sulfate prepared by this method is as follows: <5 μm, 98.2% to 91.21%; 5-15 μm, 8.7% to 9.6%; >15 μm, 0.23% to 1.2%. This indicates that the size of the basic copper sulfate prepared by this technology is much larger than 100 nm.

[0016] Given the current state of the art's difficulty in preparing nanoscale particles from solid basic copper sulfate, the present invention requires a novel approach to prepare a transparent Bordeaux mixture nanodispersion less than 100 nm, or even less than 50 nm. This also demonstrates the significant technical difficulty involved in preparing the target product.

[0017] Summary of the invention

[0018] One of the objectives of the present invention is to overcome the shortcomings of the prior art and provide a novel approach and method for preparing transparent Bordeaux mixture, distinct from existing Bordeaux mixture preparation techniques. Copper sulfate, one of the raw materials for preparing Bordeaux mixture, is first prepared into a water-in-oil (W / O) nanomicelle emulsion. A selected base compound is then added and dispersed into the micelles. A reaction occurs within the micelle "containers," generating "tailored" basic copper sulfate microparticles. The nanotemplating effect of the micelles allows the size and distribution of the basic copper sulfate microparticles to be controlled, and by controlling the influencing factors, a transparent Bordeaux mixture is obtained.

[0019] Another object of the present invention is to reduce the particle size of the active ingredient (basic copper sulfate) in Bordeaux mixture. Traditional Bordeaux mixture is the reaction of copper sulfate and quicklime in water. Quicklime is calcium oxide. Slaked lime (calcium hydroxide) is produced in water. Calcium hydroxide reacts with copper sulfate to form basic copper sulfate. Due to the low solubility of calcium hydroxide in water, and the even lower solubility of the product, basic copper sulfate, in water, the resulting Bordeaux mixture is a light blue, viscous suspension with large particle size. For ease of use, commercially, basic copper sulfate is first prepared as a solid technical in a factory and then processed into a formulation. Because basic copper sulfate is insoluble in both water and organic solvents, current technology can only process it into a wettable powder formulation or a small amount of suspension formulation through mechanical crushing and grinding. Therefore, the particle size of commercially available Bordeaux mixture ranges from a few microns to tens of microns, which increases its usage. The transparent Bordeaux mixture prepared by the present invention has a particle size of less than 100 nm, especially less than 50 nm. Compared with traditional products, the particle size is greatly reduced, thereby significantly improving the efficacy, reducing the dosage, and reducing the pollution and impact of copper preparations on the ecological environment.

[0020] Another object of the present invention is to shorten the process for obtaining Bordeaux mixture. The present invention integrates the synthesis and formulation processes of traditional Bordeaux mixture (basic copper sulfate) to directly obtain transparent Bordeaux mixture, reducing the technical synthesis and purification process, simplifying the equipment and operation process, and generating no wastewater, thereby achieving significant environmental and energy-saving effects.

[0021] The innovative ideas of the present invention are as follows:

[0022] In the first step, copper sulfate is soluble in water and dispersed as a single molecule in the aqueous solution. By selecting appropriate surfactants (adjuvants), solvents, and operating conditions, the copper sulfate aqueous solution can be prepared into an emulsion (called a nanoemulsion) formed by "water-in-oil" (W / O) nano-solubilized micelles. By selecting these conditions, the volume of the solubilized micelles can be controlled to range from a few to more than ten nanometers.

[0023] In the second step, a base compound that reacts with copper sulfate is selected and dissolved in water to form a monomolecularly dispersed solution. Under controlled operating conditions, this base compound is then added to the micelles. Within the micelles, the monomolecularly dispersed copper sulfate molecules react with the base molecules, continuously precipitating basic copper sulfate microparticles until the reaction is complete. At this point, the micelles serve as the reaction vessel. Because the micelles have a fixed volume and are uniformly distributed, they act as a "template," allowing the size and size distribution of the resulting basic copper sulfate particles to be controlled, achieving a particle size below 100 nm, particularly below 50 nm. Based on the relationship between the appearance of the colloidal solution and particle size, the resulting Bordeaux mixture is guaranteed to be transparent. Conversely, a transparent Bordeaux mixture indicates that the particles are smaller than 50 nm.

[0024] To achieve this goal, the following points must be focused on:

[0025] ⑴Preparing copper sulfate "water-in-oil" (W / O) nano-solubilized micellar emulsion is the first step to success. It involves the selection of surfactant (adjuvant) type and dosage, solvent type and dosage. Among them, the selection of emulsifier is the key. The selection of emulsifier depends on its ability to reduce the interfacial tension between the oil phase and the water phase, thereby helping to form a stable nanoemulsion. For W / O emulsions, ideal emulsifiers should be lipophilic, with an HLB value of less than 10, which means that their solubility in the oil phase is greater than their solubility in the water phase. When preparing copper sulfate W / O nanoemulsions, it is usually necessary to determine the most suitable emulsifier type and concentration through experiments to achieve the desired nanoemulsion stability and water droplet distribution characteristics. In addition, the specific conditions of the emulsification process, such as stirring speed, temperature and emulsification time, need to be considered to optimize the preparation of the nanoemulsion.

[0026] (2) The reaction of copper sulfate "water-in-oil" (W / O) nanoemulsion with alkali within the "micelles" is the second successful step. When sufficient surfactant is dissolved in the oil phase to form micelles containing aqueous droplets, the micelles provide a unique reaction container and medium for various chemical reactions. Important influencing factors include: ① The choice of surfactant. One of the key factors affecting micelle formation and stability is the type and concentration of surfactant. Selecting the right surfactant is crucial to ensure the effective formation of micelles and the success of the reaction. ② Reaction conditions. Temperature, pH value, and nanoemulsion composition (including the ratio of oil phase, aqueous phase, and surfactant) all affect the characteristics of the micelles and the progress of the reaction. ③ Solubility of the solute: The solute in the nanoemulsion (such as the reactant or catalyst) must have appropriate solubility in the corresponding phase (aqueous micelle or oil phase) to ensure the effective progress of the reaction. In this way, the W / O solubilized micellar nanoemulsion provides a unique reaction site, allowing efficient chemical reactions to proceed within its micellar aqueous phase. By carefully controlling the composition of the nanoemulsion and the reaction conditions, the efficiency and selectivity of the reaction can be optimized, opening up new possibilities for the present invention and its industrial application.

[0027] Explanation of terms

[0028] Dispersed system: A dispersed system is formed when one or more substances are dispersed in another. The dispersed substance in a dispersed system is called the dispersed phase, and the other substance is called the dispersion medium. Based on the size of the dispersed phase particles, dispersed systems are categorized as: molecular (ionic) dispersed systems (particle size < 1 nm) and colloidal dispersed systems (particle size < 100 nm).

[0029] Colloids and Sols: A colloid is a state in which matter exists at a certain degree of dispersion, rather than being an inherent state of a particular type of substance. Many normally insoluble substances can, under appropriate conditions, disperse in a medium to form a seemingly uniform solution. While superficially indistinguishable from a true solution, their diffusion rate and permeability, among other factors, place them within the realm of colloidal substances and are referred to as sols.

[0030] Classification of Colloidal Solutions: Based on their stability and the structure of their colloidal particles, they are divided into the following categories: 1. Lyophobic sols, formed by insoluble substances dispersed in a dispersion medium, are referred to as sols. These particles consist of varying numbers of molecules, exhibiting large interphases and apparent free energies. These sols are highly unstable and easily disrupted, leading to aggregation and irreversible return to their original state. 2. Solutions of polymer compounds, whose molecular size reaches the colloid range and exhibits colloidal properties, are true molecular solutions, thermodynamically stable, and reversible systems. These sols are also known as lyophilic sols.

[0031] Surfactants: Simply put, any substance that reduces the surface tension of a solvent (such as water) is called a surfactant. Surfactants are characterized by their amphiphilic molecular structure, meaning they contain both hydrophilic and lipophilic groups. This unique molecular structure reduces the surface tension of water, which has a higher surface tension than other solvents, thereby providing wetting, emulsification, foaming, defoaming, solubilization, and cleaning properties. Surfactants are categorized into small molecule surfactants and high molecular weight surfactants based on their relative molecular mass.

[0032] Micelles, critical micelle concentration, and micelle morphology: A very small number of surfactant molecules dissolved in a solvent form a monomolecular dispersion. When the concentration exceeds a certain level, several surfactant molecules aggregate to form an association called a micelle (also called a micelle). The minimum emulsifier concentration required for micelle formation is called the critical micelle concentration. Different surfactant concentrations produce different micelle morphologies, including spherical, oblate, rod-shaped, and lamellar, with sizes typically ranging from 1 to several nanometers.

[0033] Solubilizing micelles and "water-in-oil" nano-solubilizing micelles: The microstructure of micelles varies in different solvents. For example, in water, the hydrophilic groups of the surfactant molecules in the spherical micelles are on the outside, inserted into the aqueous phase, while the lipophilic groups are concentrated in the interior. In organic solvents, the opposite is true, with the hydrophilic groups concentrated in the interior of the micelles. In this case, if water or an aqueous solution is added to the system, it will enter the micelles according to the principle of like dissolves like. These micelles, which contain substances with similar properties, are called solubilizing micelles. The size of solubilizing micelles is slightly larger than that of micelles, depending on the concentration of the surfactant and the amount of solubilized substance, and is typically less than 10 nanometers in size. If the solvent is an organic solvent (also called "oil") and the solubilized substance is water or an aqueous solution, they are called "water-in-oil" nano-solubilizing micelles.

[0034] An emulsion is a dispersed system consisting of two liquids. It consists of one liquid dispersed in the form of tiny droplets throughout another immiscible liquid. Typically, one liquid is water or an aqueous solution, while the other is an organic solvent immiscible with water, generally referred to as an "oil." For a given "oil" and water, an emulsion can form either an oil-in-water emulsion (O / W), where the oil is dispersed in water, or a water-in-oil emulsion (W / O), where the water is dispersed in the oil.

[0035] The relationship between emulsion appearance and droplet size: Emulsions have internal droplets of varying sizes, which vary in their light absorption, refraction, and reflection properties, resulting in distinct appearances, as shown in the table below. Therefore, the distribution of internal droplet sizes can be roughly determined based on the emulsion's appearance. Emulsions with droplets <0.1 μm (i.e., <100 nm) are called nanoemulsions or microemulsions.

[0036] System: The so-called system refers to the system formed by the reaction of an alkaline solution with copper sulfate (W / O) nano-solubilized micelles during the preparation of a transparent Bordeaux mixture nano-basic copper sulfate micelle dispersion, under controlled addition rate and stirring. The system is formed by mixing an organic solvent, a copper sulfate (W / O) nano-solubilized micelle dispersion, an alkaline solution, a surfactant, and other substances.

[0037] Polymer additives, also known as polymer surfactants, are macromolecular compounds containing hydrophilic or lipophilic groups or backbones that are soluble in water or oil. They are also called polymer surfactants or polymer additives. Polymer additives can provide dispersion, suspension, emulsification, and stabilization. Based on the nature of the groups, they can be categorized as nonionic, anionic, cationic, and zwitterionic polymer additives.

[0038] HLB value: also known as the hydrophile-lipophile balance (HLB) or the hydrophobic balance (HLB). The combined affinity of the hydrophilic and lipophilic groups in a surfactant molecule for oil or water is called the HLB. The HLB value of a surfactant ranges from 0 to 40, with nonionic surfactants ranging from 0 to 20. For example, a paraffin molecule composed entirely of hydrophobic hydrocarbon groups has an HLB value of 0, while a surfactant composed entirely of hydrophilic oxyethylene groups has an HLB value of 20. Surfactants with both hydrocarbon and oxyethylene chains have HLB values ​​in between. A higher HLB value indicates a stronger hydrophilicity, while a lower HLB value indicates a stronger lipophilicity. The HLB value of a surfactant is closely related to its application: surfactants with HLB values ​​of 3 to 6 are suitable for use as W / O emulsifiers, while surfactants with HLB values ​​of 8 to 18 are suitable for use as O / W emulsifiers.

[0039] Mixed HLB Value: When using surfactants, it is often necessary to use a blend of surfactants to meet performance requirements. This requires knowing the HLB value of the blended surfactant. The HLB value of a blended surfactant is generally calculated by summing the mass fractions. While this method is rough, it can meet the needs of general applications. The calculation method is as follows:

[0040] For example, the HLB value of a mixed surfactant containing 80% Span 80 (HLB = 4.3) and 20% Tween 81 (HLB = 10) is:

[0041] HLB=0.8×4.3+0.2×10=5.44

[0042] Particle size: Also known as particle size, this refers to the size of the basic copper sulfate particles generated in the micelles. These particles are usually crystalline grains and do not specifically refer to the microscopic morphology of the grains. It can also refer to the size of the copper sulfate (W / O) nano-solubilized micelles.

[0043] Sub-100 nanometers: This is a statistical classification of pesticide particle sizes within a system. All particle sizes within the system exhibit a statistical distribution. The sub-100 nanometer dispersion described herein means that at least 90% of the particles are smaller than this size. Particles larger than 100 nanometers constitute only a small fraction.

[0044] Characteristics of transparent Bordeaux mixture

[0045] The transparent Bordeaux mixture is a basic copper sulfate "oil-in-water" nanoemulsion; the basic copper sulfate particles of the basic copper sulfate "oil-in-water" nanoemulsion are located in the "oil-in-water" type nano-solubilizing micelles; the size of the "oil-in-water" type nano-solubilizing micelles is less than 100 nanometers.

[0046] The basic copper sulfate particles are generated by the reaction of copper sulfate molecules and alkali molecules in the "water-in-oil" nano-solubilizing micelles.

[0047] The alkali molecule is sodium hydroxide, potassium hydroxide, ammonium hydroxide or calcium hydroxide molecule, preferably ammonium hydroxide.

[0048] The key technologies of the preparation method lie in the following aspects:

[0049] 1. Preparation of copper sulfate "water-in-oil" (W / O) nanoemulsion

[0050] The selection of emulsifier is a key step in the preparation of copper sulfate "water in oil" (W / O) nanoemulsion. The types of emulsifiers available are:

[0051] (1) Non-ionic emulsifiers. These emulsifiers are relatively stable during the emulsification process because they are not easily affected by pH and electrolytes. Commonly used emulsifiers include the Span series, the Tween series (although the Tween series is more commonly used in O / W emulsions, in some cases it can be used in combination with the Span series to adjust the emulsion's properties), and other polyoxyethylene series.

[0052] ⑵ Silicone oil emulsifier. Silicone oil emulsifier is very useful for W / O emulsions that require a particularly smooth feel or for specific applications.

[0053] ⑶ Natural emulsifiers. Such as beeswax, lanolin and natural phospholipids (such as soybean lecithin).

[0054] (4) Fatty alcohols. Long-chain fatty alcohols (such as cetyl alcohol) can also be used as emulsifiers for W / O emulsions, helping to stabilize the emulsion through their lipophilicity.

[0055] When preparing a copper sulfate W / O emulsion, experiments are required to determine the most suitable emulsifier type and concentration to achieve the desired emulsion stability and droplet distribution characteristics. Specific emulsification process conditions, such as stirring speed, temperature, and emulsification time, also need to be considered to optimize the emulsion preparation.

[0056] In addition to selecting the right emulsifier, it is also necessary to consider the use of appropriate co-surfactants and possible co-solvents to form stable, transparent nanoemulsions with low interfacial tension. Nanoemulsions differ from ordinary emulsions primarily in their extremely small droplet size (typically in the range of 10 to 100 nanometers), spontaneous formation, and unique stability characteristics.

[0057] (1) Auxiliary surfactants. To further reduce interfacial tension and increase the stability of the emulsion, auxiliary surfactants are often added. These are usually highly hydrophilic surfactants, such as the Tween series, which can form a synergistic effect with the primary surfactant.

[0058] ⑵ Cosolvent (cosolvent). Cosolvents such as ethanol, isopropanol, or butanol can help improve the solubility of surfactants in the oil phase, thereby reducing the interfacial tension of the system and facilitating the formation of nanoemulsions. The choice of cosolvent depends on the characteristics of the oil phase, aqueous phase, and surfactant.

[0059] (3) Oil phase: Select an oil phase material that is compatible with the emulsifier and co-solvent, such as medium-chain triglycerides, mineral oil or certain vegetable oils, organic solvents, etc.

[0060] Preparation steps and considerations:

[0061] (1) Formulation design: First, determine the preliminary formulation design based on the target application, including the types and ratios of surfactants and co-solvents.

[0062] (2) Mixing. Combine the oil phase, surfactant, co-solvent, and aqueous phase according to the formula ratio. Typically, the oil phase and surfactant are mixed first, followed by the co-solvent and aqueous phase containing copper sulfate.

[0063] (3) Stirring and homogenizing: Use high-speed stirring and / or ultrasonic treatment to ensure that the mixture is uniform and form a nanoemulsion.

[0064] (4) Condition optimization. It may be necessary to adjust the ratio of the components in the formula, as well as the stirring speed and time, until the required nanoemulsion properties, such as particle size, transparency, and stability, are obtained.

[0065] 2. Thoughts on the reaction of copper sulfate with calcium hydroxide (Ca(OH)2) to form basic copper sulfate

[0066] The traditional method for preparing Bordeaux mixture is the reaction of copper sulfate with calcium hydroxide (Ca(OH)2, also known as slaked lime) to produce basic copper sulfate. This method has been used in plant disease control for over a century. Its advantages and disadvantages are as follows:

[0067] advantage:

[0068] ⑴Simple operation. The reaction of calcium hydroxide and copper sulfate does not require special equipment or complicated operating steps and can be carried out directly in aqueous solution.

[0069] ⑵ Low cost. Calcium hydroxide and copper sulfate are both cheap and readily available chemicals, making the cost of the entire reaction relatively low.

[0070] ⑶ Environmentally friendly. Compared with some other chemical synthesis methods, the reactants and products used in this method are relatively environmentally friendly.

[0071] shortcoming:

[0072] ⑴ It is difficult to control the particle size. The size of basic copper sulfate particles produced by traditional methods is difficult to control, the particle size is not uniform, and nano-scale particles cannot be directly produced.

[0073] (2) It is difficult to control the purity of the product. The reaction may produce different forms of basic copper sulfate, and the purity and relative proportion may need to be optimized and adjusted in subsequent steps.

[0074] (3) It is difficult to prepare nano-sized basic copper sulfate. Since calcium hydroxide has a very low water solubility, the reactants in the system cannot form a homogeneous solution, making it difficult to control the formation of nanoparticles.

[0075] Preparation of nanometer-sized basic copper sulfate

[0076] Although the traditional reaction of calcium hydroxide and copper sulfate cannot directly produce nano-sized particles, it is theoretically possible to prepare nano-sized basic copper sulfate through improved synthesis methods and conditions. These methods include:

[0077] ⑴ Control reaction conditions: By carefully controlling the concentration of reactants, reaction temperature, stirring speed and other conditions, the precipitation rate and particle growth of the product can be affected, thereby affecting the size and morphology of the particles.

[0078] ⑵Post-processing method: Physical methods such as ball milling and ultrasonic dispersion can further reduce the particle size and improve its uniformity.

[0079] ⑶ Adding surfactants or dispersants: Adding an appropriate amount of surfactants or dispersants during or after the reaction can help stabilize the nanoparticles and prevent them from aggregation.

[0080] Specific methods and conditions

[0081] Although there is no report in the literature on the direct preparation of nano-scale basic copper sulfate by reacting calcium hydroxide with copper sulfate, the following steps can be tried as a possible method:

[0082] ⑴ Solution preparation. Prepare copper sulfate solution and calcium hydroxide solution of a certain concentration. Since the solubility of calcium hydroxide in water is low, 0.165 g / 100 g at 20°C, a larger amount of reactant solution is required.

[0083] ⑵ Slowly mix. Slowly add the calcium hydroxide solution dropwise to the copper sulfate solution while stirring. Control the addition rate and stirring speed to optimize particle formation.

[0084] ⑶ Temperature control: The reaction should be carried out at a suitable temperature. Lower temperature may help to form smaller particles.

[0085] (4) Adding a dispersant. Add an appropriate amount of dispersant or surfactant during the reaction or after the addition is completed to help stabilize the newly formed nanoparticles and prevent aggregation.

[0086] These methods and conditions need to be optimized through experimentation to achieve the optimal particle size and distribution. However, due to the low solubility of calcium hydroxide in water, using an aqueous solution requires a large volume, which poses significant difficulties for practical applications (including packaging, transportation, and field tank mixing).

[0087] 3. The reaction of copper sulfate (CuSO4) with alkali (sodium hydroxide NaOH, potassium hydroxide KOH, ammonium hydroxide NH4OH) to form basic copper sulfate

[0088] Copper sulfate (CuSO₄) can also react with sodium hydroxide (NaOH), potassium hydroxide (KOH), or ammonium hydroxide (NH₄OH) to form basic copper sulfate. Each reaction method can vary in terms of ease of implementation, mildness of reaction conditions, and yield. These differences are primarily due to the chemical properties of the reactants and the characteristics of the reaction process.

[0089] ⑴NaOH or KOH solution:

[0090] The reaction between copper sulfate (CuSO4) and sodium hydroxide (NaOH) or potassium hydroxide (KOH) is the same. It can produce copper hydroxide or basic copper sulfate. Take potassium hydroxide as an example:

[0091] CuSO4+2KOH→Cu(OH)2↓+K2SO4

[0092] 2CuSO4+2KOH→Cu2(OH)2SO4↓+K2SO4

[0093] From the two reaction equations above, the difference between producing copper hydroxide and basic copper sulfate lies primarily in the amount of alkali used. The reaction of two molecules of alkali with one molecule of copper sulfate primarily produces copper hydroxide (Cu(OH)2) precipitate. To form basic copper sulfate, the amount of alkali must be controlled—that is, reduced so that it does not completely neutralize all the copper ions in the copper sulfate, allowing some copper ions to precipitate as basic copper sulfate. The ideal amount of alkali depends on the exact chemical formula of the desired basic copper sulfate, specifically the ratio between copper sulfate and hydroxide.

[0094] Ease of implementation and reaction conditions

[0095] ① Feasibility: It is relatively easy to react CuSO4 with NaOH or KOH to form basic copper sulfate, because NaOH and KOH have high solubility in water and can quickly react with copper sulfate to form copper hydroxide precipitate. The formation of basic copper sulfate can then be promoted by adjusting conditions (such as solution concentration and pH value).

[0096] ② Reaction conditions: These reactions usually proceed at room temperature and do not require special temperature control, which are mild reaction conditions.

[0097] ③ Yield: The yield is relatively high because the formation of the product can be optimized by precisely controlling the amount of reactants and reaction time.

[0098] ⑵NH4OH solution:

[0099] Copper sulfate (CuSO4) reacts with ammonium hydroxide (NH4OH) to form basic copper sulfate, similar to the reaction described above for sodium hydroxide and potassium hydroxide. The exact chemical composition of basic copper sulfate may vary depending on the reaction conditions and the ratio of the reactants. Another common form is:

[0100] 3CuSO4+6NH4OH→Cu3(OH)4(SO4)2↓+2(NH4)2SO4+2H2O

[0101] This reaction represents the reaction of three copper sulfate molecules with six ammonium hydroxide molecules to produce one basic copper sulfate molecule, two ammonium sulfate molecules, and water. This reaction equation is based on a specific form of basic copper sulfate; the actual product composition may vary depending on experimental conditions (e.g., reactant concentrations, solution pH, temperature, etc.).

[0102] Ease of implementation and reaction conditions

[0103] ① Feasibility: Although basic copper sulfate can also be generated by reacting NH4OH with CuSO4, this process may be more complicated than the NaOH or KOH solution because ammonia (NH4OH) is a weak base in water, and its ability to generate copper hydroxide is relatively weak, and the reaction rate is relatively slow, but this is beneficial for controlling the particle size.

[0104] ② Reaction conditions: The reaction conditions of NH4OH are also mild, but due to its weaker alkalinity, a higher concentration or more reaction time may be required to achieve the same reaction progress.

[0105] ③ Yield: The yield may be limited by the reaction conditions (such as the concentration of ammonium hydroxide, the pH of the solution, etc.). Compared with NaOH or KOH, it may not be as easy to optimize the macroscopic solid yield.

[0106] Main comparison of the two solutions

[0107] ⑴ Chemical properties: NaOH and KOH are strong bases that can react with CuSO4 quickly and effectively; while NH4OH is a weak base and its reaction rate is slower.

[0108] ⑵ Reaction rate and yield: The rate and yield of the reaction of NaOH and KOH are usually higher than those of the reaction of NH4OH because the strong base can more effectively promote the formation of precipitates.

[0109] ⑶ Ease of operation: The use of NaOH and KOH is usually easier to control and implement due to their fast reaction speed and simple operation, especially in laboratory experiments to prepare bulk solids.

[0110] In summary, NaOH or KOH schemes are usually more favored when preparing basic copper sulfate solid products in the laboratory because these schemes have advantages in speed of response, simplicity of operation and productive rate. However, considering that the purpose of the present invention is to prepare a transparent aqueous dispersion of nano basic copper sulfate, the particle size is small, and the ammonium hydroxide scheme of selecting a slower reaction rate and slowing down the formation of precipitation should be more suitable.

[0111] 4. Preparation of Nano Basic Copper Sulfate

[0112] When selecting the most suitable method for preparing nanoscale basic copper sulfate, considerations include reaction conditions, the ability to control the reactants, and the stability and dispersibility of the final product. Although copper sulfate can be reacted with sodium hydroxide (NaOH), potassium hydroxide (KOH), or ammonium hydroxide (NH4OH) to form basic copper sulfate, certain methods may offer advantages over others for producing nanoparticles.

[0113] Preparation of nano-scale basic copper sulfate

[0114] (1) Using NaOH or KOH: These strong bases react quickly with CuSO4, which helps to quickly form a precipitate. Although the formation of nanoparticles can be promoted by carefully controlling the addition rate, concentration, and mixing method of the reactants, it is difficult to obtain a transparent and stable nanoparticle dispersion.

[0115] Using NH₄OH: Although the reaction rate of NH₄OH is slower, the precipitate produced by this method may have easier control over its growth rate, helping to form nanoparticles with more uniform size. In addition, using ammonia (NH₄OH) as a reaction medium may help stabilize the nanoparticles and prevent excessive growth under certain conditions.

[0116] Solution Selection

[0117] In the preparation of nanoscale basic copper sulfate, the use of NH₄OH may offer greater flexibility in controlling particle size distribution due to its potentially slower reaction rate. Furthermore, selecting the optimal method requires consideration of nanoparticle stabilization techniques, such as the selection of appropriate dispersants and surface modifiers, which are equally important for preventing particle aggregation.

[0118] Based on the difficulty of obtaining basic copper sulfate and the purpose of preparing transparent Bordeaux mixture with a particle size of less than 100 nm, especially less than 50 nm, the present invention selects a reaction scheme of copper sulfate with sodium hydroxide, potassium hydroxide, and ammonium hydroxide through evaluation and comparison of the above schemes, and preferably selects a reaction scheme of copper sulfate with ammonium hydroxide.

[0119] Commercial production of basic copper sulfate is aimed at obtaining high-purity solid technical materials for further use in formulation processing. The transparent Bordeaux mixture prepared in this invention, however, is used directly for crop spraying without purification. The so-called "by-products" in this system, such as (NH₄)₂SO₄ produced by ammonium hydroxide and K₂SO₄ produced by potassium hydroxide, can be used as nitrogen and potassium fertilizers for crop growth, effectively utilizing resources.

[0120] 5. Reaction of Copper Sulfate "Water-in-Oil" (W / O) Nanoemulsion in "Micelles"

[0121] Reactions with bases are feasible within the "micelles" of copper sulfate "water-in-oil" (W / O) nanoemulsions. Especially when the system contains sufficient surfactant to form nanosolubilized micelles of the aqueous phase droplets, this provides a unique reaction "container" and medium for a variety of chemical reactions, including those that are difficult or inefficient to perform in traditional solvent systems.

[0122] Possibility of micellar reactions:

[0123] (1) Micelle formation: In W / O nanoemulsions, when the surfactant concentration reaches a certain level (critical micelle concentration, CMC), the surfactant molecules spontaneously aggregate to form nanomicelles. These nanomicelles are primarily present in the entire emulsion system consisting of the oil phase. When a copper sulfate aqueous solution is added, aqueous copper sulfate droplets are present within the nanosolubilized micelles.

[0124] (2) Reaction Environment: The aqueous copper sulfate droplets within the nanomicelles provide a unique nanoscale reaction environment, acting as a microreactor. When an alkaline aqueous solution is added to the system, it spontaneously enters the solubilizing micelle reactor and undergoes a chemical reaction based on the principle of like dissolves like. Controlling the rate of addition of the alkaline aqueous solution can control the reaction process and, in other words, the rate of formation of the target product. This environment is particularly well-suited for reactions requiring a specific reaction environment or catalyst.

[0125] (3) Reaction type: In nanoemulsions containing micelles, various chemical reactions can be carried out, including catalytic reactions, polymerization reactions, phase transfer catalysis, etc. In particular, for those reactions that can be catalyzed or accelerated in the presence of surfactants, the use of nanoemulsions as reaction media may bring significant advantages.

[0126] Considerations:

[0127] (1) Choice of surfactant: One of the key factors affecting micelle formation and stability is the type and concentration of surfactant. Selecting the right surfactant is crucial to ensure the effective formation of micelles and the success of the reaction.

[0128] ⑵ Reaction conditions: temperature, pH value and nanoemulsion composition (including the ratio of oil phase, water phase and surfactant) will affect the characteristics of micelles and the progress of the reaction.

[0129] ⑶ Solubility of solute: The solute (e.g. reactant) in the nanoemulsion must have appropriate solubility in the corresponding phase (aqueous micelle or oil phase) to ensure the effective conduct of the reaction.

[0130] In summary, W / O nanoemulsions provide a unique reaction vessel for efficient chemical reactions within their aqueous micelles. By carefully controlling the composition of the nanoemulsion and reaction conditions, reaction efficiency and selectivity can be optimized, opening up new possibilities for research and industrial applications.

[0131] Preparation method of transparent Bordeaux mixture (nano basic copper sulfate)

[0132] The present invention adopts the following technical solutions:

[0133] A method for preparing transparent Bordeaux mixture comprises two steps:

[0134] 1) using a surfactant and a solvent to prepare a copper sulfate aqueous solution into a nanoemulsion in the form of "water-in-oil" nano-solubilized micelles;

[0135] 2) adding an aqueous solution of an alkali compound into the nanoemulsion, so that the aqueous solution enters the interior of the "water-in-oil" nanosolubilizing micelles; inside the "water-in-oil" nanosolubilizing micelles, copper sulfate molecules react with alkali molecules to generate basic copper sulfate nanoparticles.

[0136] The size of the basic copper sulfate particles is below 100 nanometers.

[0137] The base molecule of the alkaline compound is sodium hydroxide, potassium hydroxide, ammonium hydroxide or calcium hydroxide; preferably ammonium hydroxide.

[0138] The surfactant is a lipophilic surfactant; the HLB value of the surfactant is less than 10.

[0139] The HLB value of the surfactant is in the range of 2 to 8, preferably 3 to 6.

[0140] When two or more surfactants are used, the HLB of the mixed surfactants is less than 10.

[0141] The HLB value of the mixed surfactant ranges from 2 to 8, preferably from 3 to 6.

[0142] The preparation method according to claim 19, characterized in that the solvent is a hydrophobic solvent; at least one of the following:

[0143] Coconut oil, palm oil, medium-chain triglycerides; mineral oils such as liquid paraffin oil; ester solvents such as butyl acetate and isopropyl acetate; ketone solvents such as cyclohexanone and isophorone.

[0144] The step 1) comprises the following two sub-steps:

[0145] 1.1) Dissolve at least one of the surfactants in at least one of the solvents and stir to form a transparent solution, referred to as Solution A. Then, dissolve a certain amount of anhydrous copper sulfate in water to prepare an aqueous solution at 20°C with a concentration of less than 17% by mass, the solution being transparent sky blue, referred to as Solution B.

[0146] 1.2) Solution B was added to solution A under stirring to form a transparent "water-in-oil" nanoemulsion in the form of nano-solubilized micelles, referred to as solution C.

[0147] The step 2) includes the following two sub-steps:

[0148] 2.1) preparing at least one alkaline compound into an aqueous solution of a certain concentration, referred to as solution D;

[0149] 2.2) Add solution D to solution C with stirring to obtain a clear Bordeaux mixture.

[0150] During preparation, the addition speed and stirring speed should be controlled to keep the solution transparent until solution D is added.

[0151] 1. Selection of surfactant (emulsifier)

[0152] A surfactant having an HLB value of less than 10 is selected, preferably a surfactant having an HLB value of 2 to 8, more preferably a surfactant having an HLB value of 3 to 6.

[0153] For example, ethylene glycol fatty acid ester (Emcol EO-50, 2.7), propylene glycol monostearate (Emcol PO-50, 3.4), glycerol monostearate (3.8), sorbitan (Span) series: Span 65 (2.1), Span 80 (4.3), Span 60 (4.7), diethylene glycol fatty acid ester (Emcol DP-50, 5.1), diethylene glycol monolaurate (6.1), oleic acid polyoxyethylene ether (A-103, 6.5), castor oil series, EL10 (6-7), Span 20 (8.6), etc.

[0154] It does not exclude the selection of surfactants with an HLB value greater than 10. However, they must be used in combination with surfactants with an HLB value less than 10 so that the HLB of the mixed surfactants (which can be calculated by the mass fraction addition method) meets the requirement of less than 10.

[0155] Surfactants with HLB values ​​close to or greater than 10 include polyoxypropylene stearate (9), polyoxyethylene sorbitan ester (Tween) series: Tween 61 (9.6), Tween 81 (10), Tween 65 (10.5), Tween 85 (11); EL series: EL 20 (9-10), EL 40 (13-14); polyoxyethylene laurate, LAE 4 (9-10); polyoxyethylene oleate series: A 105 (8.5-9.5), A 10 (12-13), A 115 (14), etc.

[0156] 2. Selection of solvent

[0157] The principles for selecting a hydrophobic solvent are low or non-toxicity, environmental friendliness, a high flash point, good hydrophobicity, immiscibility with water, and favorable formation of W / O micelles. Possible solvents include: vegetable oils such as coconut oil, palm oil, and medium-chain triglycerides; mineral oils such as liquid paraffin; organic solvents such as ester solvents such as butyl acetate and isopropyl acetate; and ketone solvents such as cyclohexanone and isophorone.

[0158] 3. Preparation of copper sulfate "water-in-oil" (W / O) nanoemulsion

[0159] Dissolve a certain amount of one or more surfactants in a certain amount of one or more solvents and stir to form a transparent solution, referred to as Solution A. Then, dissolve a certain amount of anhydrous copper sulfate in water to prepare a transparent sky-blue solution, referred to as Solution B. Given the solubility of anhydrous copper sulfate (20.7 g / 100 g water, 20°C), the mass percent concentration of its saturated solution is approximately 17%. For system stability, a subsaturated aqueous solution is best prepared.

[0160] The preferred copper sulfate of the present invention has a mass percentage concentration of less than 17% at 20°C.

[0161] Under stirring, an aqueous copper sulfate solution (solution B) was added to a transparent solution of dissolved surfactant (solution A) to form a transparent copper sulfate "water-in-oil" (W / O) nanoemulsion, referred to as solution C.

[0162] 4. Preparation of basic copper sulfate "water-in-oil" (W / O) nanoemulsion

[0163] A certain amount of selected alkaline compounds, any one or more of sodium hydroxide, potassium hydroxide or ammonium hydroxide, is prepared into an aqueous solution of a certain concentration, which is called solution D.

[0164] Solution D is added to Solution C in a certain manner while stirring. The reaction conditions, mainly the addition rate and stirring speed, are controlled to ensure that the solution remains transparent until the addition of Solution D is complete. Stirring is continued for a certain period of time, and the resulting dispersion remains transparent, resulting in the target product - transparent Bordeaux mixture.

[0165] [Implementation Method]

[0166] Example 1

[0167] According to the following reaction ratio

[0168] 2CuSO4+2NH4OH→Cu2(OH)2SO4↓+(NH4)2SO4

[0169] Component ratio: The following is the mass ratio and preparation method of each component to obtain a transparent nanoemulsion of about 12 grams of basic copper sulfate:

[0170] How to do it:

[0171] (1) In a suitable container, dissolve the components of component 1 under stirring to obtain a transparent solution A.

[0172] (2) In another appropriate container, dissolve the components of component 2 under stirring to obtain a transparent solution B.

[0173] ⑶ Under stirring, add solution B into the container containing solution A, stir and disperse to form a transparent dispersion, and obtain copper sulfate "water-in-oil" (W / O) nanoemulsion, which is solution C.

[0174] (4) While stirring, add aqueous ammonia (Solution D) dropwise to the above-generated Solution C. Control the addition and stirring speed to ensure uniform dispersion and maintain transparency. After addition, continue stirring for several minutes to obtain the target product—a transparent Bordeaux mixture nanoemulsion.

[0175] Example 2

[0176] According to the following reaction ratio

[0177] 3CuSO4+6NH4OH→Cu3(OH)4(SO4)2↓+2(NH4)2SO4+2H2O

[0178] Component ratio: The following is the mass ratio and preparation method of each component to obtain a transparent nanoemulsion of about 14 grams of basic copper sulfate:

[0179] How to do it:

[0180] (1) In a suitable container, dissolve the components of component 1 under stirring to obtain a transparent solution A.

[0181] (2) In another appropriate container, dissolve the components of component 2 under stirring to obtain a transparent solution B.

[0182] ⑶ Under stirring, add solution B into the container containing solution A, stir and disperse to form a transparent dispersion, and obtain copper sulfate "water-in-oil" (W / O) nanoemulsion, which is solution C.

[0183] (4) While stirring, add aqueous ammonia (Solution D) dropwise to the above-generated Solution C. Control the addition and stirring speed to ensure uniform dispersion and maintain transparency. After addition, continue stirring for several minutes to obtain the target product—a transparent Bordeaux mixture nanoemulsion.

Claims

1. A transparent Bordeaux liquid, wherein the transparent Bordeaux liquid is a basic copper sulfate "water-in-oil" nanoemulsion; the basic copper sulfate particles of the basic copper sulfate "water-in-oil" nanoemulsion are located in the "water-in-oil" type nano-solubilizing micelles; the size of the "water-in-oil" type nano-solubilizing micelles is less than 100 nanometers.

2. The transparent Bordeaux mixture according to claim 1, characterized in that: The basic copper sulfate particles are generated by the reaction of copper sulfate molecules and alkali molecules in the "water-in-oil" nano-solubilization micelles.

3. The transparent Bordeaux mixture according to claim 2, characterized in that: The alkali molecules are sodium hydroxide, potassium hydroxide, ammonium hydroxide or calcium hydroxide molecules.

4. A method for preparing a transparent Bordeaux mixture, comprising two steps: 1) using a surfactant and a solvent, preparing a copper sulfate aqueous solution into a nanoemulsion in the form of "water-in-oil" nano-solubilized micelles; 2) adding an aqueous solution of an alkali compound into the nanoemulsion to allow it to enter the interior of the "water-in-oil" nanosolubilizing micelles; inside the "water-in-oil" nanosolubilizing micelles, copper sulfate molecules react with alkali molecules to generate basic copper sulfate nanoparticles.

5. The preparation method according to claim 4, wherein the particle size of the basic copper sulfate is below 100 nanometers.

6. The preparation method according to claim 4, wherein the base molecule described in the base compound is sodium hydroxide, potassium hydroxide, ammonium hydroxide or calcium hydroxide; preferably ammonium hydroxide.

7. The preparation method according to claim 4, characterized in that: The surfactant is a lipophilic surfactant; the HLB value of the surfactant is less than 10.

8. The preparation method according to claim 7, characterized in that: The HLB value of the surfactant is in the range of 2-8, preferably 3-6.

9. The preparation method according to claim 4, characterized in that: In the step 1), at least one surfactant is used; when one surfactant is used, the HLB value of the surfactant is less than 10; when at least two surfactants are used, the mixed HLB value of all surfactants is less than 10.

10. The preparation method according to claim 7, characterized in that: The surfactant is one of the following: Ethylene glycol monofatty acid ester, propylene glycol monostearate, glycerol monostearate, sorbitan series, diethylene glycol fatty acid ester, diethylene glycol monolaurate, oleic acid polyoxyethylene ether, castor oil series, EL-10.

11. The preparation method according to claim 10, characterized in that: The dehydrated sorbitol series includes: Span 20, Span 60, Span 65, and Span 80.

12. The preparation method according to claim 9, characterized in that: When at least two surfactants are used, the second surfactant is one of the following: Polyoxypropylene stearate, polyoxyethylene sorbitan ester, Tween series, EL series, polyoxyethylene laurate, LAE-4, oleic acid polyoxyethylene ester series, A-105, A-10, A-115.

13. The preparation method according to claim 12, characterized in that: The polyoxyethylene sorbitan ester Tween series includes: Tween 61, Tween 81, Tween 65, Tween 85.

14. The preparation method according to claim 5, characterized in that: In the step 1), the following types of surfactants are used: Nonionic emulsifier, silicone oil emulsifier, natural emulsifier, fatty alcohol.

15. The preparation method according to claim 4, characterized in that: In the step 1), the solvent is a hydrophobic solvent.

16. The preparation method according to claim 15, characterized in that: The solvent is at least one of the following: Coconut oil, palm oil, medium chain triglycerides; mineral oils, such as liquid paraffin oil; ester solvents, such as butyl acetate, isopropyl acetate; ketone solvents, such as cyclohexanone, isophorone.

17. The preparation method according to claim 4, characterized in that: The step 1) comprises the following two sub-steps: 1.1) dissolving at least one of the surfactants in at least one of the solvents, stirring and dissolving to form a transparent solution, referred to as solution A; then dissolving a certain amount of anhydrous copper sulfate in water, preparing an aqueous solution with a mass percentage concentration of less than 17% at 20° C., the solution is transparent sky blue, referred to as solution B; 1.2) Solution B is added to solution A under stirring to form a transparent "water-in-oil" nanoemulsion in the form of nano-solubilized micelles, referred to as solution C.

18. The preparation method according to claim 4, characterized in that: The step 2) comprises the following two sub-steps: 2.1) preparing at least one alkaline compound into an aqueous solution of a certain concentration, referred to as solution D; 2.2) Add solution D to solution C under stirring to obtain a transparent Bordeaux mixture.

19. The preparation method according to claim 18, characterized in that: Control the addition speed and stirring speed to keep the solution transparent until solution D is added.

20. A method of using the transparent Bordeaux mixture according to any one of claims 1 to 3 for preventing and controlling plant diseases and as a nutrient element.

21. The method of use according to claim 20, wherein the plant is a grapevine, potato, peach tree, apple tree or banana.

22. The method of use according to claim 20, wherein the plant diseases are fungal and bacterial disease infections on plants.

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