Compound comprising ferrocene structure, method for preparing same, and use thereof

Abstract

The present invention relates to the technical field of fire safety. Disclosed are a compound comprising a ferrocene structure, a method for preparing same, and use thereof. The compound has the structure of general formula (W). The compound provided herein has excellent flame-retardant capacity. The compound can be used for preparing a fire extinguishing agent with high fire extinguishing efficiency and capabilities of quickly extinguishing open flames, fast cooling, and effectively preventing reburning.

Description

Compounds containing ferrocene structure, their preparation methods and applications

[0001] Cross-references to related applications

[0002] This application claims the benefit of two Chinese patent applications filed on November 27, 2024, 2024, namely 202411713397.9 and 202411713389.4, the contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to the field of fire safety technology, specifically to a compound containing a ferrocene structure, its preparation method, and its application. Background Technology

[0004] Fires are a serious problem facing human society. Even in countries with small populations, tens of thousands of fires occur every year, endangering human lives and property and damaging the environment.

[0005] As an effective means of extinguishing fires, extinguishing agents are promptly deployed to the combustion sites of various substances. The mechanisms of action of extinguishing agents are mainly divided into isolation, suffocation, cooling, and chemical inhibition.

[0006] Battery fires fall under Class A, B, C, and D fire categories, and are difficult to extinguish with existing single extinguishing agents. Furthermore, lithium battery energy storage systems are mostly containerized, with batteries densely packed together. A typical 40-foot 2.5MWh energy storage compartment contains approximately 6510 120Ah individual cells. This high energy density and tendency for thermal runaway to spread easily generate a large amount of heat, significantly hindering firefighting efforts.

[0007] The rapid development of lithium battery energy storage has also been accompanied by frequent fire accidents. In the past five years, dozens of fire accidents have occurred at energy storage power stations at home and abroad, exposing the problem of insufficient fire-fighting capabilities of energy storage battery systems.

[0008] The basic development process of a lithium battery fire is as follows: Under the influence of external factors, the internal temperature of the battery rises, triggering multiple chain side reactions, generating a large amount of heat, and causing thermal runaway. The flammable gases and electrolyte vapors generated by the side reactions increase the pressure inside the battery casing, causing the safety valve to rupture. The ejected high-temperature flammable gas mixture forms a jet fire or accumulates inside the compartment, igniting and exploding upon contact with an ignition source. During this process, the thermal runaway of individual cells continues to propagate within the system, triggering larger-scale battery combustion, increasing the scale of the fire and the difficulty of extinguishing it.

[0009] In the fight against lithium battery fires, battery fires are often difficult to extinguish because the three elements necessary for combustion can be provided by the battery itself. Solid extinguishing agents are almost ineffective, and gaseous extinguishing agents have limited cooling properties for lithium battery fires, thus offering poor prevention of reignition. Water is the preferred extinguishing agent for lithium battery fires. Liquid extinguishing agents for battery fires are mostly water-based, including pure water, water with additives, and foam. Water has an extremely high specific heat capacity and excellent cooling properties; however, extinguishing battery fires with water requires a very large amount of water, and water's conductivity makes it destructive to the battery.

[0010] In the fight against solid and liquid fires, commonly used extinguishing agents include foam extinguishing agents. However, traditional foam extinguishing agents use fluorocarbon surfactants as their core components. They have the characteristics of spreading rapidly on the surface of burning oil and inhibiting the volatilization of flammable liquids. Therefore, they can quickly extinguish oil fires and are widely used in the petrochemical industry.

[0011] Heptafluoropropane is a clean gaseous fire extinguishing agent, primarily using chemical extinguishing methods while also possessing physical extinguishing properties. It is highly efficient, low in toxicity, and does not deplete the ozone layer, making it an ideal halon substitute. However, its cooling effect is poor, and it can decompose at high temperatures to produce the toxic gas HF. Perfluorohexanone is another ideal halon substitute, exhibiting high chemical extinguishing efficacy, environmental friendliness, and good safety. It is a liquid at room temperature with a boiling point of 49°C. During extinguishing, it absorbs heat through vaporization, resulting in a cooling effect superior to heptafluoropropane. Therefore, some energy storage systems have been replaced with perfluorohexanone fire extinguishing systems. However, the latent heat of vaporization of perfluorohexanone is only 1 / 25 that of water, making it unsuitable for large-scale thermal runaway. Dry powder fire extinguishing agents consist of fine inorganic powders with extinguishing properties (such as ammonium phosphate and sodium bicarbonate) and other fillers and additives, primarily extinguishing fires through chemical inhibition. However, current research indicates that dry powder fire extinguishing agents have poor cooling effects and are unsuitable for battery fire extinguishing. Aerosol fire extinguishing agents are sol systems formed by dispersing solid particles smaller than 5 μm into the gas phase. These tiny particles possess gaseous properties, exhibiting good diffusion and long residence time within the protected space, resulting in higher extinguishing efficiency than dry powder fire extinguishing agents. Based on their formation mechanism, they can be classified into thermal aerosols and cold aerosols. Thermal aerosols are generated through the combustion of solid fuels, while cold aerosols are formed by mechanically crushing ultrafine powders and then ejecting them into the fire space. Existing research indicates that, due to their cooling effect, aerosol fire extinguishing agents are less suitable for battery fires.

[0012] Aqueous film-forming foam (AFFF) is widely recognized as the best-performing Class B fire extinguishing agent and enjoys a high market share. However, recent studies have found that perfluorooctane sulfonic acid (PFOS) and its salts used in AFFF are difficult to degrade, posing serious ecological damage and environmental problems. Therefore, it has been listed as a "persistent organic pollutant" (POPS) under the Stockholm Convention and its use is restricted worldwide.

[0013] In addition, existing fire extinguishing agents are not very effective, or require the addition of various flame-retardant substances to achieve a better fire extinguishing effect.

[0014] Therefore, developing a new type of fire extinguishing agent that can effectively extinguish fires with chemical means and consumes little water is an important problem that needs to be solved in this field. Summary of the Invention

[0015] The purpose of this invention is to overcome the problems of low fire extinguishing efficiency, high water consumption, and easy reignition of existing fire extinguishing agents, and to provide a compound containing a ferrocene structure with high fire extinguishing function.

[0016] To achieve the above objectives, a first aspect of the present invention provides a compound containing a ferrocene structure, the compound having the general formula shown in formula (W):

[0017] In formula (W), ring A represents a saturated cycloalkyl group with 3-10 carbon atoms;

[0018] In formula (W), there are 1 to n Q groups, where n is the number of sites in ring A that can be substituted.

[0019] The Q group is a flame-retardant structural unit, and at least one Q group has at least one ferrocene derivative structural unit attached to its free end.

[0020] The ferrocene derivative structural unit has the structure shown in formula (I-1), where R in formula (I-1) is selected from unsubstituted or substituted C groups from at least one group in combination B. 1-6 At least one of alkylene groups, -O-, -C(O)-, and -C(O)-NH-; the combination B is composed of -OH, -COOH, -NH2, -SO3H, and -P(O)(OH)2;

[0021] The flame-retardant structural unit is selected from at least one of phosphate groups, phosphate ester groups, phosphonic acid groups, phosphonate ester groups, amide groups, and imide groups, and the flame-retardant structural unit optionally contains alkali metal atoms.

[0022] A second aspect of the present invention provides a method for preparing a ferrocene phytate derivative of formula (I), the method comprising:

[0023] (1) In the presence of a catalyst, the compound shown in formula (I-2) is subjected to esterification with phytic acid to obtain the esterified product;

[0024] Optionally, the method further includes: (2) reacting the esterified product with a base;

[0025] The definitions of R, R1, and R2 are the same as those described in the first aspect above.

[0026] A third aspect of the present invention provides a ferrocene phytate derivative prepared by the method described in the second aspect above.

[0027] The fourth aspect of the present invention provides the use of the ferrocene-containing compounds described in the first aspect and / or the ferrocene phytate derivatives described in the third aspect as flame retardants.

[0028] The ferrocene-containing compounds and / or ferrocene phytate derivatives of the present invention can be applied to various solid and liquid fires.

[0029] Compared with the prior art, the present invention has the following main advantages:

[0030] (1) Combustion is a typical chain reaction, consisting of three stages: chain initiation, chain propagation, and chain termination. First, under external influences such as heat or electricity, reactant molecules break down to form highly reactive free radicals. Subsequently, these free radicals rapidly react with reactant molecules, generating new free radicals to continue the reaction. Finally, the free radicals combine or react to form normal molecules, and no new free radicals are generated, thus terminating the reaction. In this process, free radicals play a crucial intermediate role; therefore, by eliminating free radicals, the reaction chain can be broken, achieving the purpose of extinguishing a fire. The ferrocene-containing compounds provided by this invention have a high content of flame-retardant elements (such as phosphorus) and exhibit excellent flame-retardant properties. In these compounds, iron atoms combine with water and air to form active intermediates such as FeO and Fe2O3. These active intermediates can bind with key free radicals such as O·, O2, and OH· generated during combustion, blocking free radical chain reactions. When used as a flame retardant in fire extinguishing agents, the phosphorus in these compounds forms a char layer during the extinguishing process, reducing heat transfer from the flame to the combustible material, thus extinguishing fires efficiently and quickly. Furthermore, the ferrocene-containing fire extinguishing agents of this invention decompose into iron atoms in the flame. These iron atoms react with free radicals in the flame to eliminate free radicals. Therefore, this fire extinguishing agent can replace fire extinguishing agents such as heptafluoropropane, perfluorohexanone, dry powder, and aerosols in enclosed spaces (such as battery compartments, large warehouses, and underground garages).

[0031] (2) The method for preparing compounds containing ferrocene structures provided by the present invention is simple.

[0032] (3) The ferrocene-containing compounds provided by this invention have excellent flame retardant properties. Using the ferrocene-containing compounds as flame retardants to prepare water-based fire extinguishing agents has a strong inhibitory effect on various battery (especially lithium-ion battery) fires. It can block the free radical combustion chain reaction, and can carry out fire extinguishing operations more efficiently. It has high fire extinguishing efficiency and can also quickly extinguish open flames. It has a rapid cooling effect and effectively prevents reignition. Furthermore, due to the short fire extinguishing time and small amount of fire extinguishing agent, the water consumption is greatly reduced and the cooling effect is improved.

[0033] (4) The extinguishing agent provided by this invention has a wide range of applications, especially suitable for battery fire extinguishing, and can also be used to extinguish Class A and Class B fires. When used to extinguish battery fires, the extinguishing agent provided by this invention can extinguish open flames in a very short time and prevent reignition. Furthermore, this invention has verified through examples that when using the extinguishing agent described in this invention to extinguish battery fires, reignition will not occur within 24 hours.

[0034] (5) The main component of the fire extinguishing agent formed by the ferrocene compound provided by this invention is water. When applied to, for example, a burning battery, the ferrocene compound dissolved in the water first evaporates upon heating and undergoes thermal decomposition, releasing iron atoms to annihilate free radicals in the flame, thereby weakening and eliminating the open flame. After the flame is extinguished or weakened, the heat radiation of the flame to the battery will be reduced or eliminated, lowering the intensity of the battery's thermal runaway. At the same time, the water in the fire extinguishing agent cools the battery casing and the damaged battery opening. Once the temperature inside the battery drops to 70°C, the thermal runaway inside the battery stops, eliminating the risk of reignition. In other words, this fire extinguishing agent accelerates cooling under the synergistic effect of the ferrocene compound and water, achieving the prevention of reignition. Attached Figure Description

[0035] Figure 1 is the infrared characterization spectrum of compound 3 containing a ferrocene structure prepared in Preparation Example 1;

[0036] Figure 2 is the phosphorus NMR spectrum of compound 3 containing a ferrocene structure prepared in Preparation Example 1.

[0037] Figure 3 is the first-order mass spectrum of compound 3 containing a ferrocene structure prepared in Preparation Example 1;

[0038] Figure 4 is a secondary mass spectrum of compound 3 containing a ferrocene structure prepared in Preparation Example 1.

[0039] Figure 5 is the primary mass spectrum of compound 4 containing a ferrocene structure prepared in Preparation Example 2;

[0040] Figure 6 is a secondary mass spectrum of compound 4 containing a ferrocene structure prepared in Preparation Example 2;

[0041] Figure 7 is the phosphorus NMR spectrum of compound 4 containing a ferrocene structure prepared in Preparation Example 2. Detailed Implementation

[0042] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0043] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0044] In this invention, room temperature is defined as 25±2℃.

[0045] In this invention, "at least one group in all R1 and all R2 is a group represented by formula (I-1)" means that in formula (I), at least one group in all R1 and all R2 is a group represented by formula (I-1). For example, in formula (I), in all R1, there is one group represented by formula (I-1) while R2 does not contain a group represented by formula (I-1).

[0046] In this invention, "C" 1-6 "Alkylene" refers to a straight-chain or branched alkylene with 1-6 carbon atoms. The alkylene refers to a residue formed by the loss of two hydrogen atoms from an alkane. These two hydrogen atoms can be two hydrogen atoms on the same carbon atom or two hydrogen atoms on different carbon atoms. It can be straight-chain or branched, for example, a straight-chain alkylene with a total of 1, 2, 3, 4, 5, or 6 carbon atoms, or a branched alkylene with a total of 3, 4, 5, or 6 carbon atoms. 1-6 The alkylene groups may include, but are not limited to: -CH2-, -CH2-CH2-, -CH2-CH2-CH2-, -CH(CH3)-CH2-, -CH2-CH(CH3)-, -CH2-(CH2)2-CH2-, -C(CH3)2-CH2-, -CH2-C(CH3)2-, etc.

[0047] In this invention, "-C(O)-NH-" indicates that either a ketone group or -NH- can be linked to the parent nucleus structure.

[0048] As previously stated, a first aspect of the present invention provides a compound containing a ferrocene structure, the compound having the general formula shown in formula (W):

[0049] In formula (W), ring A represents a saturated cycloalkyl group with 3-10 carbon atoms;

[0050] In formula (W), there are 1 to n Q groups, where n is the number of sites in ring A that can be substituted.

[0051] The Q group is a flame-retardant structural unit, and at least one Q group has at least one ferrocene derivative structural unit attached to its free end.

[0052] The ferrocene derivative structural unit has the structure shown in formula (I-1), where R in formula (I-1) is selected from unsubstituted or substituted C groups from at least one group in combination B. 1-6 At least one of alkylene groups, -O-, -C(O)-, and -C(O)-NH-; the combination B is composed of -OH, -COOH, -NH2, -SO3H, and -P(O)(OH)2;

[0053] The flame-retardant structural unit is selected from at least one of phosphate groups, phosphate ester groups, phosphonic acid groups, phosphonate ester groups, amide groups, and imide groups, and the flame-retardant structural unit optionally contains alkali metal atoms.

[0054] Preferably, ring A in formula (W) represents a saturated cycloalkyl group having 4-8 carbon atoms; more preferably, ring A in formula (W) represents a saturated cycloalkyl group having 4-6 carbon atoms.

[0055] Preferably, the flame-retardant structural unit is a phosphate group, and the flame-retardant structural unit optionally contains alkali metal atoms.

[0056] Preferably, ring A in formula (W) represents a saturated cycloalkyl group with 6 carbon atoms; the flame-retardant structural unit is a phosphate group, and the flame-retardant structural unit optionally contains alkali metal atoms.

[0057] More preferably, the number of Q groups in formula (W) is 1-6.

[0058] Preferably, the solubility of the compound with the structure shown in formula (W) is ≥3g / 100g water.

[0059] Preferably, based on the molecular weight of the compound with the structure shown in formula (W), the sum of the contents of P, N and Fe elements in the compound with the structure shown in formula (W) is 20.5wt%-28.3wt%.

[0060] According to a particularly preferred embodiment, the compound with the structure shown in formula (W) is a ferrocene phytate derivative having the structure shown in formula (I).

[0061] Each R1 may be the same or different; each R2 may be the same or different.

[0062] Each R1 and each R2 is independently selected from H, sodium, potassium and the group shown in formula (I-1); at least one of the groups in all R1 and all R2 is the group shown in formula (I-1); and R1 and R2 attached to the same phosphate ester group are not simultaneously the groups shown in formula (I-1);

[0063] In formula (I-1), R is selected from C that is unsubstituted or substituted by at least one group in combination B. 1-6 At least one of alkylene, -O-, -C(O)-, -C(O)-NH-; the combination B is composed of -OH, -COOH, -NH2, -SO3H, -P(O)(OH)2.

[0064] In the preferred case, each R1 may be the same or different; each R2 may be the same or different.

[0065] Each R1 and each R2 is independently selected from H, sodium, potassium and the group shown in formula (I-1); at least one of the groups in all R1 and all R2 is the group shown in formula (I-1); and R1 and R2 attached to the same phosphate ester group are not simultaneously the groups shown in formula (I-1);

[0066] In equation (I-1), R is selected from C. 1-6 Alkylene.

[0067] Preferably, each R1 and each R2 is independently selected from H, sodium, and the group shown in formula (I-1);

[0068] In equation (I-1), R is selected from C. 1-3 Alkylene. Exemplarily, R is -CH2-, -CH2CH2-, or -CH2CH2CH2-.

[0069] More preferably, in formula (I-1), R is -CH2-. The inventors of the present invention have discovered that, in this preferred embodiment, the ferrocene-containing compound provided by the present invention exhibits superior flame-retardant properties.

[0070] In a preferred embodiment, the number of groups represented by formula (I-1) in the ferrocene phytate derivative is ≤6.

[0071] More preferably, the number of groups represented by formula (I-1) in the ferrocene phytate derivative is 1, 2, or 3. The inventors of this invention have discovered that, in this preferred embodiment, the ferrocene-containing compound provided by this invention exhibits superior flame-retardant properties.

[0072] According to a particularly preferred embodiment, the compound with the structure shown in formula (W) is selected from any of the following:

[0073] Compound 1:

[0074] Compound 2:

[0075] Compound 3:

[0076] Compound 4:

[0077] Compound 5:

[0078] Compound 6:

[0079] This invention does not impose any particular requirements on the method for preparing the aforementioned compounds containing the ferrocene structure. Those skilled in the art can synthesize them using known synthetic methods in the field of synthesis based on the structural formulas provided by this invention. Several synthetic methods for compounds are exemplarily provided below, but these should not be construed as limiting the invention.

[0080] For example, the ferrocene-structured compound has the general formula shown in formula (W):

[0081] The method includes:

[0082] Flame-retardant groups are introduced onto the polycyclic ring A through sulfonation, phosphorylation, amidation, hydrolysis, oxidation, and halogenation. The product shown in formula (W) is obtained through Friedel-Crafts acylation, affinity addition, and condensation reactions of ferrocene derivatives.

[0083] For example: (1) Under light conditions, cyclohexane reacts with chlorine to produce 1-chlorocyclohexane. 1-Chlorocyclohexane reacts with ammonia to produce aminocyclohexane; using pyridine as an acid-binding agent, aminocyclohexane reacts with acetyl chloride through an acylation reaction to produce acetamylcyclohexane;

[0084] (2) Using DMAP as a catalyst, acetamidocyclohexane and ferrocene acetic acid undergo a condensation reaction to produce the product shown below.

[0085] According to a particularly preferred embodiment, the present invention provides a method for preparing the ferrocene phytate derivative of formula (I), the method comprising:

[0086] (1) In the presence of a catalyst, the compound shown in formula (I-2) is subjected to esterification with phytic acid to obtain the esterified product;

[0087] Optionally, the method further includes: (2) reacting the esterified product with a base;

[0088] The definitions of R, R1, and R2 are the same as those described in the first aspect above.

[0089] The inventors discovered through research that compounds containing ferrocene structures, obtained by esterifying the compound described in formula (I-2) with phytic acid, or by further reacting the compound described in formula (I-2) with a base after esterification, all exhibit excellent flame-retardant properties. Furthermore, the preparation method of this invention is simple and easy to operate.

[0090] Preferably, in step (1), the molar ratio of the compound shown in formula (I-2) to phytic acid is 1.2-6.5:1; more preferably, the molar ratio of the compound shown in formula (I-2) to phytic acid is 1.2-2.5:1, and can be 1.2:1, 1.5:1, 1.8:1, 2:1, 2.2:1 or 2.5:1, for example.

[0091] In a preferred embodiment, in step (1), the catalyst is a combination of dicyandiamide and urea; preferably, in the catalyst, the molar ratio of dicyandiamide to urea is 0.4-1.2:1.

[0092] Preferably, in step (1), the conditions for the esterification reaction include: a temperature of 70-90°C and a time of 4-6 hours.

[0093] More preferably, the molar ratio of urea to phytic acid is 0.5-1.5:1.

[0094] Preferably, the method further includes, in step (1), the esterification reaction is carried out in the presence of a solvent and a dehydrating agent.

[0095] In a preferred embodiment, the dehydrating agent is selected from at least one of toluene, xylene, and cyclohexane.

[0096] Preferably, the weight ratio of the dehydrating agent to the phytic acid is 0.5-1:1.

[0097] It should be noted that the present invention does not have special requirements for the solvent; any solvent known in the art may be used. Preferably, the solvent is selected from at least one of dimethyl sulfoxide, toluene, and cyclohexane. More preferably, it is dimethyl sulfoxide.

[0098] According to a preferred embodiment, the method includes purifying the ferrocene-containing compound using a post-processing method known in the art. Exemplarily, the solvent, dehydrating agent, and excess of the compound represented by formula (I-2) can be removed by washing with water and vacuum distillation to obtain the ferrocene-containing compound.

[0099] In a preferred embodiment, the method further includes the operation of step (2); the molar ratio of the esterification product to the base is 1:9-11.

[0100] Preferably, the alkali is sodium hydroxide and / or potassium hydroxide.

[0101] Preferably, in step (2), the conditions for the contact reaction include: a temperature of 20-40°C and a time of 0.2-1h.

[0102] As previously stated, a third aspect of the present invention provides a ferrocene phytate derivative prepared by the method described in the second aspect above.

[0103] As previously stated, the fourth aspect of the present invention provides the use of the ferrocene-containing compounds described in the first aspect and / or the ferrocene phytate derivatives described in the third aspect as flame retardants.

[0104] The present invention will be described in detail below through examples, but the scope of protection of the present invention is not limited thereto. In the following preparation examples and embodiments, the raw materials used were purchased from Shanghai Maclean, and the sources of other materials are as follows:

[0105] 3% aqueous film-forming foam fire extinguishing agent: purchased from Jiangsu Jiangya Company;

[0106] 4.2MPa piped perfluorohexanone gas fire extinguishing system: purchased from Jinan Noah Company;

[0107] The preparation examples of the present invention are used to prepare compounds containing ferrocene structures, and the amount of phytic acid used in the preparation examples is 1 mol.

[0108] Preparation Example 1

[0109] At 20°C, hydroxymethyl ferrocene, phytic acid, and catalysts (dicyandiamide and urea) were dissolved in dimethyl sulfoxide (solvent). After complete dissolution, cyclohexane (a dehydrating agent) was added, and the mixture was heated to 70°C. After reacting for 4 hours, the temperature was lowered to room temperature. The solvent, dehydrating agent, and excess hydroxymethyl ferrocene were removed by repeated washing with water and vacuum distillation to obtain ferrocene methyl phytate, compound 3. The molar ratio of hydroxymethyl ferrocene to phytic acid was 1.2:1; the molar ratio of phytic acid to urea was 1:1; the molar ratio of dicyandiamide to urea was 0.5:1; and the mass ratio of the dehydrating agent to phytic acid was 0.5:1.

[0110] Figure 1 shows the infrared spectrum of the compound containing the ferrocene structure prepared in this preparation example, and Figure 2 shows the phosphorus NMR spectrum of the compound containing the ferrocene structure prepared in this preparation example. Figure 3 shows the primary mass spectrum of compound 3 containing the ferrocene structure prepared in Preparation Example 1.

[0111] As can be seen from Figure 1, 3415cm -1 The peak for phytic acid is the -OH peak at 2850 cm⁻¹.-1 This is a saturated CH peak, 1699 cm⁻¹ -1 The peak is P=O, at 1080 cm⁻¹. -1 The peak for the newly generated POC is at 1189 cm⁻¹. -1 It is the primary alcohol -OH on hydroxymethylferrocene. Additionally, 481 cm⁻¹ -1 The peaks at this location represent the cyclopentadienyl rings and Fe.

[0112] As shown in Figure 2, the absorption peak at 3.3 ppm is the phosphate monoester bond in phytic acid, and the shifted peak at -0.75 ppm is the absorption peak of the newly formed phosphate diester bond. This proves that hydroxymethyl ferrocene has been successfully esterified with phytic acid.

[0113] As can be seen from Figures 3 and 4, the first-order mass spectrum shows a signal peak at 857.87, which is consistent with the molecular mass of compound 3; the second-order mass spectrum shows the gradual removal of the hydroxymethyl ferrocene group from compound 3 at 858→793→737→672→659.

[0114] In summary, the ferrocene-containing compound prepared in this example has the structure shown in compound 3.

[0115] Preparation Example 2

[0116] At 20°C, hydroxymethyl ferrocene, phytic acid, and catalysts (dicyandiamide and urea) were dissolved in dimethyl sulfoxide (solvent). After complete dissolution, toluene (a dehydrating agent) was added, and the mixture was heated to 90°C and reacted for 6 hours before being cooled to room temperature. The solvent, dehydrating agent, and excess hydroxymethyl ferrocene were removed by repeated washing with water and vacuum distillation to obtain disubstituted ferrocene phytate methyl ester, compound 4. The molar ratio of hydroxymethyl ferrocene to phytic acid was 3:1; the molar ratio of phytic acid to urea was 1.2:1; the molar ratio of dicyandiamide to urea was 0.5:1; and the mass ratio of the dehydrating agent to phytic acid was 1:1.

[0117] Phytic acid molecules contain six phosphate groups and twelve hydroxyl groups, including four weakly acidic groups, two moderately acidic groups, and six strongly acidic groups. Within the weakly acidic pKa range of 5.7, one hydrogen atom in the phytic acid molecule dissociates; within the pKa range of 6.8–7.6, two hydrogen atom dissociates; and within the pKa range of 10.0–12.0, three hydrogen atom dissociates.

[0118] Figure 5 is the primary mass spectrum of compound 4 containing a ferrocene structure prepared in Preparation Example 2; Figure 6 is the secondary mass spectrum of compound 4 containing a ferrocene structure prepared in Preparation Example 2; Figure 7 is the phosphorus NMR spectrum of compound 4 containing a ferrocene structure prepared in Preparation Example 2.

[0119] As shown in Figures 5 and 6, the first-order mass spectrum shows a signal peak at 1055.89, which corresponds to the molecular mass of compound 4. The second-order mass spectrum shows a peak at 1056→991→935→870→814→750→686→658, which corresponds to the process of compound 4 gradually removing two hydroxymethyl ferrocene groups.

[0120] According to Figure 7, the absorption peaks at 2.08 ppm to 3.40 ppm are the phosphate monoester bonds in the phytic acid group; the absorption peaks at -1.43 ppm to -0.79 ppm are the phosphate diester bonds in the two symmetrical ferrocene methylene groups. The methyl ferrocene group increases the electronegativity of the O directly connected to P, causing a low-field shift in the peak position.

[0121] In summary, the ferrocene-containing compound prepared in this example has the structure shown in compound 4.

[0122] Preparation Example 3

[0123] Ferrocene phytate (as shown in compound 3) and sodium hydroxide were reacted at 25°C for 0.2 h to obtain compound 1, which contains a ferrocene structure.

[0124] The molar ratio of compound 3 to sodium hydroxide is 1:11.

[0125] Preparation Example 4

[0126] Ferrocene methyl phytate (as shown in compound 4) and sodium hydroxide were reacted at 25°C for 0.2 h to obtain compound 2, which contains a ferrocene structure.

[0127] The molar ratio of compound 4 to sodium hydroxide is 1:10.

[0128] A water-based fire extinguishing agent was prepared using the compound of the present invention, which was dissolved in water to form an aqueous solution. This aqueous solution was then used as the water-based fire extinguishing agent for fire extinguishing tests.

[0129] The preparation method of water-based fire extinguishing agent is as follows: add a compound containing ferrocene structure to water (the balance in the system) at 50℃ and 200rpm, and stir until uniform to obtain a water-based fire extinguishing agent with a mass concentration of 4wt%.

[0130] Test case

[0131] Experiments were conducted in an outdoor development space, where eight commercially available lithium-ion batteries (12V, 200Ah, approximately 320mm x 270mm x 115mm) were connected in series, and a heating plate was used to trigger thermal runaway. After the batteries caught fire, the water-based fire extinguishing agent of this invention and commercially available fire extinguishing agents (3% aqueous film-forming foam extinguishing agent, ABC type dry powder extinguishing agent, and a 4.2MPa piped perfluorohexanone gas fire extinguishing system) were used to extinguish the fire. One extinguishing agent nozzle was positioned directly above the burning battery module, pointing towards the burning battery, at a distance of 1000mm. Specific experimental conditions and test results are shown in Table 1.

[0132] Table 1

[0133] Test Case B

[0134] Experimental conditions: A Class B fire (oil pan fire) was tested using a fine water mist method. The oil pan was 1.5m in diameter, 400mm high, and 3mm thick, made of cast iron. A 20mm thick layer of diesel fuel was injected into the pan, with a 10mm thick water cushion layer at the bottom. After the diesel fuel was ignited and allowed to burn freely for 1 minute, a fine water mist was sprayed from the top of the oil pan for fire extinguishing. The fine water mist nozzle was positioned 1800mm above the center of the oil pan, pointing towards the center, ensuring the fine water mist completely covered the pan. The flow rate of the fine water mist was 1L / s, and the spray pressure was 2.5MPa.

[0135] The results are shown in Table 2.

[0136] Table 2

[0137] Test Case C

[0138] Experimental conditions: A Class A fire (woodpile fire) was tested using a direct-flow water jet. A Class A woodpile fire test apparatus was constructed according to the method described in GB 4351-2023 for portable fire extinguishers. This involved constructing a 16-layer woodpile using 112 wooden strips, with 7 strips per layer. Each strip was 635mm long and had a 40mm square cross-section. 2L of diesel fuel was used to ignite the bottom of the woodpile. When the woodpile had burned to 55% of its remaining mass, the extinguishing agent was sprayed to extinguish the fire. After extinguishing the fire, the area was observed for 10 minutes to check for reignition. The extinguishing agent solution was placed in a 9L portable fire extinguisher with an initial pressure of 1.2MPa and a direct-flow nozzle.

[0139] The results are shown in Table 3.

[0140] Table 3

[0141] As can be seen from the results in Table 1, using the ferrocene derivatives described in this invention as flame retardants to prepare water-based fire extinguishing agents can not only quickly extinguish open flames after extinguishing battery fires, but also effectively prevent reignition, and the amount of fire extinguishing agent used is small.

[0142] As can be seen from Table 2, in the case of Class B fires, the ferrocene derivatives described in this invention, when used as flame retardants to prepare water-based fire extinguishing agents, exhibit a significantly enhanced fire extinguishing effect compared to fine water mist from pure water, highlighting the excellent fire extinguishing capability of the compounds of this invention.

[0143] As can be seen from Table 3, in the case of Class A fires, the ferrocene derivatives described in this invention, when used as flame retardants to prepare water-based fire extinguishing agents, exhibit a significant fire extinguishing enhancement effect compared to pure water, highlighting the excellent fire extinguishing capability of the compounds of this invention.

[0144] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A compound containing a ferrocene structure, characterized in that, The compound has the general structure shown in formula (W): In formula (W), ring A represents a saturated cycloalkyl group with 3-10 carbon atoms; In formula (W), there are 1 to n Q groups, where n is the number of sites in ring A that can be substituted. The Q group is a flame-retardant structural unit, and at least one Q group has at least one ferrocene derivative structural unit attached to its free end. The ferrocene derivative structural unit has the structure shown in formula (I-1), where R in formula (I-1) is selected from unsubstituted or substituted C groups from at least one group in combination B. 1-6 At least one of alkylene groups, -O-, -C(O)-, and -C(O)-NH-; the combination B is composed of -OH, -COOH, -NH2, -SO3H, and -P(O)(OH)2; The flame-retardant structural unit is selected from at least one of phosphate groups, phosphate ester groups, phosphonic acid groups, phosphonate ester groups, amide groups, and imide groups, and the flame-retardant structural unit optionally contains alkali metal atoms.

2. The compound according to claim 1, characterized in that, In formula (W), ring A represents a saturated cycloalkyl group having 4-8 carbon atoms; preferably, ring A in formula (W) represents a saturated cycloalkyl group having 4-6 carbon atoms. Preferably, the flame-retardant structural unit is a phosphate group, and the flame-retardant structural unit optionally contains alkali metal atoms.

3. The compound according to claim 1, characterized in that, In formula (W), ring A represents a saturated cycloalkyl group with 6 carbon atoms; the flame-retardant structural unit is a phosphate group, and the flame-retardant structural unit optionally contains alkali metal atoms; Preferably, there are 1 to 6 Q groups in formula (W).

4. The compound according to any one of claims 1-3, characterized in that, The solubility of compounds with the structure shown in formula (W) is ≥3 g / 100 g water; Preferably, based on the molecular weight of the compound with the structure shown in formula (W), the sum of the contents of P, N and Fe elements in the compound with the structure shown in formula (W) is 20.5wt%-28.3wt%.

5. The compound according to any one of claims 1-4, characterized in that, The compound with the structure shown in formula (W) is a ferrocene phytate derivative, which has the structure shown in formula (I). Each R1 may be the same or different; each R2 may be the same or different. Each R1 and each R2 is independently selected from H, sodium, potassium and the group shown in formula (I-1); at least one of the groups in all R1 and all R2 is the group shown in formula (I-1); and R1 and R2 attached to the same phosphate ester group are not simultaneously the groups shown in formula (I-1); In formula (I-1), R is selected from C that is unsubstituted or substituted by at least one group in combination B. 1-6 At least one of alkylene, -O-, -C(O)-, -C(O)-NH-; the combination B is composed of -OH, -COOH, -NH2, -SO3H, -P(O)(OH)2.

6. The compound according to claim 5, characterized in that, Each R1 and each R2 is independently selected from H, sodium, and the group shown in formula (I-1); In equation (I-1), R is selected from C. 1-3 Alkylene; Preferably, in formula (I-1), R is -CH2-.

7. The compound according to claim 5, characterized in that, The number of groups represented by formula (I-1) in the ferrocene phytate derivative is ≤6; Preferably, the number of groups represented by formula (I-1) in the ferrocene phytate derivative is 1, 2 or 3.

8. The compound according to any one of claims 1-7, characterized in that, The compounds with the structure shown in formula (W) are selected from any of the following:

9. A method for preparing the ferrocene phytate derivative of formula (I), characterized in that, The method includes: (1) In the presence of a catalyst, the compound shown in formula (I-2) is subjected to an esterification reaction with phytic acid to obtain an esterified product; optionally, the method further includes: (2) reacting the esterified product with a base; The definitions of R, R1, and R2 are the same as those in any one of claims 5-8.

10. The method according to claim 9, characterized in that, In step (1), the molar ratio of the compound shown in formula (I-2) to phytic acid is 1.2-6.5:1; preferably, the molar ratio of the compound shown in formula (I-2) to phytic acid is 1.2-2.5:

1.

11. The method according to claim 9, characterized in that, In step (1), the catalyst is a combination of dicyandiamide and urea; preferably, the molar ratio of dicyandiamide to urea in the catalyst is 0.4-1.2:

1. And / or, in step (1), the conditions for the esterification reaction include: a temperature of 70-90°C and a time of 4-6 h; preferably, the molar ratio of urea to phytic acid is 0.5-1.5:

1.

12. The method according to any one of claims 9-11, characterized in that, In step (1), the esterification reaction is carried out in the presence of a solvent and a dehydrating agent.

13. The method according to claim 12, characterized in that, The dehydrating agent is selected from at least one of toluene, xylene, and cyclohexane; Preferably, the weight ratio of the dehydrating agent to the phytic acid is 0.5-1:

1.

14. The method according to any one of claims 9-13, characterized in that, The method further includes the operation of step (2); the molar ratio of the esterification product to the base is 1:9-11; preferably, the base is sodium hydroxide and / or potassium hydroxide; preferably, in step (2), the conditions of the contact reaction include: temperature of 20-40℃ and time of 0.2-1h.

15. Ferrocene phytate derivatives prepared by the method according to any one of claims 9-14.

16. The use of the ferrocene-containing compound as described in any one of claims 1-8, or the ferrocene phytate derivative as described in claim 15, as a flame retardant.

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