Preparation method for enhancing thermal stability of phosphate ester compound by cyclotriphosphazene derivative
Incorporating triazine derivatives into phosphoric acid esters addresses thermal instability and compatibility issues, enhancing stability and extending their lifespan in high-temperature applications.
Patent Information
- Application Number
- CN202510452318.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-11
- Publication Date
- 2025-07-15
AI Technical Summary
Phosphate compounds are prone to decomposition under high temperature environments, resulting in an increase in acid value and an unstable degradation product, affecting their performance and life, and are at the same time poor in compatibility with other materials.
Cyclotriphosphazene derivatives are used as additives to compound them with phosphate compounds, and their compatibility and thermal stability are improved by regulating the type and proportion of substituent groups.
Effectively inhibit the decomposition of phosphate esters under high temperature conditions, extend their service life, and broaden their application range. It is suitable for a variety of phosphate material systems.
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Abstract
Description
Technical Field
[0001] The present invention belongs to the field of functional additives. Specifically, it relates to a method for effectively enhancing the thermal stability of a phosphate compound by adding a controllably synthesized cyclotriphosphazene derivative thereto in part. Background Art
[0002] Cyclotriphosphazene is an important phosphorus-nitrogen compound. It has a six-membered ring skeleton formed by alternating single and double bonds of stable and flame-retardant N and P elements, endowing it with good high-temperature stability. Cyclotriphosphazene derivatives can be directly compounded with compounds or introduced into compounds through chemical reactions to improve the thermal stability of the compounds. Zhao et al. used the bridged cyclotriphosphazene flame retardant bisphenol A bridged penta(aniline) cyclotriphosphazene to compound with epoxy resin, and the flame retardancy and smoke suppression of the obtained composite material were significantly improved; Liu et al. used a fluorine-containing phosphazene derivative as an electrolyte additive to improve the electrochemical performance and safety of the positive electrode of a lithium nickel manganese oxide battery.
[0003] The basic structure of phosphate compounds can be expressed as (RO)3P=O. Due to their unique chemical structure, phosphate compounds have good thermal stability and excellent antioxidant properties and are widely used in different industrial fields such as high-temperature lubricating oils, flame retardant materials, and ion battery electrolytes. However, phosphate compounds are prone to decomposition under high-temperature conditions, resulting in an increase in acid value and the formation of unstable degradation products, thus affecting their service performance and service life. When phosphates are applied to electrolytes, there are problems such as a large addition amount, an increase in viscosity, and instability. Cyclotriphosphazene derivatives have good flame retardancy and thermal stability, and can improve the flame retardant performance of battery electrolytes by compounding with phosphates without affecting the performance.
[0004] The present invention provides a novel additive based on cyclotriphosphazene derivatives, which can improve the high-temperature performance of phosphate compounds. Phosphate compounds contain polar P=O and P-OR phosphate bonds, and the P-N bond in the structure of phosphazene derivatives is also polar. Therefore, the two have an affinity at the molecular level and it is easier to obtain a uniform mixed system. In addition, in addition to the backbone structure, the compatibility, thermal stability, and antioxidant ability with phosphate compounds can be further improved by regulating the type and proportion of the side chain groups of cyclophosphazene, and it can be widely applicable to a variety of phosphate material systems. Summary of the Invention
[0005] To overcome the insufficient stability of single phosphate compounds in high-temperature environments and solve the problem of poor compatibility with other materials, the present invention provides a method using cyclotriphosphazene derivatives as additives. These additives have excellent thermal stability, can effectively inhibit the decomposition of phosphate compounds under high-temperature conditions, extend their service life, broaden their application scope, and can regulate the compatibility with different types of phosphates by designing the types of phosphazene substituents and controlling the synthesis, making it suitable for optimizing the high-temperature performance of various phosphate materials.
[0006] The technical solution adopted in the present invention is as follows:
[0007] The cyclotriphosphazene derivative of formula (I) of the present invention is compounded with phosphate, and the thermal stabilities of single phosphate, cyclotriphosphazene derivative, and the compounded system are measured.
[0008] In formula (I), n and m are the statistical average numbers of the corresponding substituents, n, m = any number from 0 to 6, R1 is a fluoroalkoxy group, where the substitution of fluorine can be designed according to requirements, and the number of alkyl groups can be designed according to requirements, such as trifluoroethoxy, octafluoropentoxy; R2 is a phenoxy group, such as phenoxy, m-methylphenoxy, p-methylphenoxy; R3 is a fluorophenoxy group, the substitution of fluorine can be designed according to requirements, phenoxy groups such as phenoxy, m-methylphenoxy, p-methylphenoxy, and fluorophenoxy groups such as m-trifluoromethylphenoxy. By selecting different R1, R2, R3 groups and regulating the values of n and m, the compatibility and thermal stability with phosphate compounds can be improved to different degrees, and this method can be widely applied to various phosphate material systems.
[0009] The specific operation method includes:
[0010] (A) Prepare the reaction solution of the corresponding sodium phenoxide or / and the corresponding sodium alcoholate according to the ratios of R1, R2, and R3 in structure (I);
[0011] (B) Prepare the reaction solution of substituted hexachlorocyclotriphosphazene;
[0012] (C) Dropwise add the solution in step (A) into the reaction solution system in step (B), heat under reflux, and collect the obtained cyclotriphosphazene derivative;
[0013] (D) Add 20 - 40 wt% of the cyclotriphosphazene derivative collected in step (C) to the phosphate compound;
[0014] (E) Test the improvement of thermal stability in step (D) by thermogravimetric analysis.
[0015] The reaction solvents in steps (A), (B), and (C) are tetrahydrofuran, toluene, acetonitrile, etc., and 25 - 25 g of solvent is added for every 10 g of the total reactants.
[0016] The reflux reaction time in step (C) is 48 hours.
[0017] The heating temperature in step (C) is 70 °C.
[0018] In steps (A), (B), and (C), the feeding ratios of sodium phenoxide and sodium alcoholate are 1.1 - 1.3 times the stoichiometry.
[0019] The phosphate ester compounds in step (D) are trioctyl phosphate, tributyl phosphate, and tris(butoxyethyl) phosphate.
[0020] In step (E), the temperature range of the thermogravimetric analysis experiment is set to 30 - 600 °C, and the heating rate is controlled at 5 °C / min.
[0021] In the present invention, cyclotriphosphazene and phosphate ester compounds have good compatibility and can effectively improve the thermal stability of single phosphate esters. Research shows that when 20 - 40 wt% of cyclotriphosphazene derivatives are added, the thermal decomposition temperature of various phosphate ester compounds is increased by 20 - 40 °C. The present invention is applicable to fields such as high-temperature lubrication, flame retardant compounding, battery electrolytes, etc., and provides an efficient method for improving the thermal stability of phosphate ester compounds. Brief Description of the Drawings
[0022] Figure 1 It is the TG curve graph after adding 30% of cyclophosphazene derivatives to single trioctyl phosphate in Example 1;
[0023] Figure 2 It is the TG curve graph after adding 30% of cyclophosphazene derivatives to single tris(butoxyethyl) phosphate in Example 2;
[0024] Figure 3 It is the TG curve graph after adding 30% of cyclophosphazene derivatives to single tributyl phosphate in Example 5 Detailed Description of the Invention
[0025] To better understand the present invention, the following further description is made in combination with specific embodiments, but the present invention is not limited to the following examples.
[0026] Example 1
[0027] According to n = 4, m = 1, R1 is octafluoropentoxy, R2 is m-methylphenoxy, and R3 is m-trifluoromethylphenoxy in formula (I), cyclotriphosphazene derivatives are synthesized and added to trioctyl phosphate.
[0028] In a dry reactor, 13.92 g (0.04 mol) of hexachlorocyclotriphosphazene and 30 mL of THF solvent were added. Subsequently, a 120 mL THF solution containing sodium octafluoropentoxide, sodium m-methylphenoxide, and sodium m-trifluoromethylphenoxide was added dropwise. The solution contained 48.26 g (0.19 mol) of sodium octafluoropentoxide, 5.72 g (0.044 mol) of sodium m-methylphenoxide, and 7.08 g (0.044 mol) of sodium m-trifluoromethylphenoxide. The mixed system was heated to 70 °C and refluxed for 48 h. After the reaction was completed, it was washed twice with deionized water, the product was extracted with petroleum ether, the upper layer liquid was collected, and the final product was obtained after drying and rotary evaporation. When added to trioctyl phosphate at 30 wt%, the corresponding temperature was 293 °C when the new compounded system reached 50% thermal weight loss; the specific TG curve is shown in Figure 1 。
[0029] Example 2
[0030] According to n = 4, m = 1 in formula (I), R1 is octafluoropentyloxy, R2 is m-methylphenoxy, and R3 is m-trifluoromethylphenoxy, a cyclotriphosphazene derivative was synthesized and added to tris(2-butoxyethyl) phosphate.
[0031] In a dry reactor, 13.92 g (0.04 mol) of hexachlorocyclotriphosphazene and 30 mL of THF solvent were added. Subsequently, a 120 mL THF solution containing 48.26 g (0.19 mol) of sodium octafluoropentoxide, 5.72 g (0.044 mol) of sodium m-methylphenoxide, and 7.08 g (0.044 mol) of sodium m-trifluoromethylphenoxide was added dropwise. The mixed system was heated to 70 °C and refluxed for 48 h. After the reaction was completed, it was washed twice with deionized water, the product was extracted with petroleum ether, the upper layer liquid was collected, and the final product was obtained after drying and rotary evaporation. When added to tris(2-butoxyethyl) phosphate at 30 wt%, the corresponding temperature was 295 °C when the new compounded system had 50% thermal weight loss. The specific TG curve is shown in Figure 2 。
[0032] Example 3
[0033] According to n = 4, m = 1 in formula (I), R1 is octafluoropentyloxy, R2 is m-methylphenoxy, and R3 is m-trifluoromethylphenoxy, a cyclotriphosphazene derivative was synthesized and added to tributyl phosphate.
[0034] In a dry reactor, 13.92 g (0.04 mol) of hexachlorocyclotriphosphazene and 30 mL of THF solvent were added. Subsequently, 120 mL of a THF solution containing 48.26 g (0.19 mol) of sodium octafluoropentanolate, 5.72 g (0.044 mol) of sodium m-methylphenolate, and 7.08 g (0.044 mol) of sodium m-trifluoromethylphenolate was added dropwise. The mixed system was heated to 70 °C and refluxed for 48 h. After the reaction was completed, it was washed twice with deionized water, the product was extracted with petroleum ether, the upper layer liquid was collected, and the final product was obtained after drying and rotary evaporation. When 30 wt% was added to tributyl phosphate, the corresponding temperature at which the new compounded system had a 50% thermal weight loss was 224 °C.
[0035] Example 4
[0036] In formula (I), n = 0, m = 6, R2 is m-methylphenoxy, a cyclotriphosphazene derivative was synthesized and added to trioctyl phosphate.
[0037] In a dry reactor, 22.62 g (0.07 mol) of hexachlorocyclotriphosphazene and 50 mL of THF solvent were added. Subsequently, 120 mL of a THF solution containing 55.9 g (0.43 mol) of sodium m-methylphenolate was added dropwise. The mixed system was heated to 70 °C and refluxed for 48 h. After the reaction was completed, it was washed twice with deionized water, the product was extracted with petroleum ether, the upper layer liquid was collected, and the final product was obtained after drying and rotary evaporation. When 30 wt% was added to trioctyl phosphate, the corresponding temperature at which the new compounded system had a 50% thermal weight loss was 324 °C.
[0038] Example 5
[0039] In formula (I), n = 0, m = 6, R2 is m-methylphenoxy, a cyclotriphosphazene derivative was synthesized and added to tributyl phosphate.
[0040] In a dry reactor, 22.62 g (0.07 mol) of hexachlorocyclotriphosphazene and 50 mL of THF solvent were added. Subsequently, 120 mL of a THF solution containing 55.9 g (0.43 mol) of sodium m-methylphenolate was added dropwise. The mixed system was heated to 70 °C and refluxed for 48 h. After the reaction was completed, it was washed twice with deionized water, the product was extracted with petroleum ether, the upper layer liquid was collected, and the final product was obtained after drying and rotary evaporation. When 30 wt% was added to tributyl phosphate, the corresponding temperature at which the new compounded system had a 50% thermal weight loss was 358 °C; for the specific TG curve, see Figure 3 .
[0041] Example 6
[0042] In formula (I), n = 6, m = 0, R1 is trifluoroethoxy, a cyclotriphosphazene derivative was synthesized and added to trioctyl phosphate.
[0043] In a dry reactor, 22.62 g (0.07 mol) of hexachlorocyclotriphosphazene and 50 mL of THF solvent were added. Subsequently, 120 mL of a THF solution of 67.1 g (0.55 mol) of sodium trifluoroethanolate was added dropwise, and the mixed system was heated to 70 °C and refluxed for 48 h. After the reaction was completed, it was washed twice with deionized water, the product was extracted with petroleum ether, the upper layer liquid was collected, and the final product was obtained after drying and rotary evaporation. When 30 wt% was added to trioctyl phosphate, the corresponding temperature at which the new compounded system had a 50% thermal weight loss was 201 °C.
[0044] Example 7
[0045] In formula (I), n = 0, m = 3, R2 is m-methylphenoxy, R3 is m-trifluoromethylphenoxy, a cyclotriphosphazene derivative was synthesized and added to trioctyl phosphate.
[0046] In a dry reactor, 17.4 g (0.05 mol) of hexachlorocyclotriphosphazene and 40 mL of THF solvent were added. Subsequently, 100 mL of a THF solution of 36.8 g (0.2 mol) of sodium m-trifluoromethylphenolate and 26 g (0.2 mol) of sodium m-trifluoromethylphenolate were added dropwise, and the mixed system was heated to 70 °C and refluxed for 48 h. After the reaction was completed, it was washed twice with deionized water, the product was extracted with petroleum ether, the upper layer liquid was collected, and the final product was obtained after drying and rotary evaporation. When 30 wt% was added to trioctyl phosphate, the corresponding temperature at which the new compounded system had a 50% thermal weight loss was 350 °C.
[0047] Evaluation of the effect of the compounded system:
[0048] Table 1 shows the decomposition temperatures of single phosphates and the examples at a 50% thermal weight loss.
[0049] Sample Thermal decomposition temperature (°C) Trioctyl phosphate 251 Tributyl phosphate 184 Tris(butoxyethyl) phosphate 265 Example 1 293 Example 2 295 Example 3 224 Example 4 324 Example 5 358 Example 6 201 Example 7 350 。
Claims
1. A cyclotriphosphazene derivative-enhanced phosphate compound, characterized in that, The structural formula is as follows: In formula (I), n and m are the statistical average numbers of the corresponding substituents, n, m are any numbers from 0 to 6, R1 is a fluoroalkoxy group, where the substitution of fluorine can be designed according to requirements, and the number of alkyl groups can be designed according to requirements, such as trifluoroethoxy, octafluoropentoxy; R2 is a phenoxy group, such as phenoxy, m-methylphenoxy, p-methylphenoxy; R3 is a fluorophenoxy group, the substitution of fluorine can be designed according to requirements, phenoxy groups such as phenoxy, m-methylphenoxy, p-methylphenoxy, fluorophenoxy groups such as m-trifluoromethylphenoxy.
2. A method for preparing the cyclotriphosphazene derivative-enhanced phosphate compound according to claim 1, characterized in that, It includes the following steps: (A) Prepare a reaction solution of the corresponding sodium phenoxide or / and the corresponding sodium alcoholate according to the ratio of R1R2R3 of structure (I); (B) Prepare a reaction solution of substituted hexachlorocyclotriphosphazene; (C) Dropwise add the solution in step (A) to the reaction solution system in step (B), heat under reflux, and collect the obtained cyclotriphosphazene derivative.
3. The method according to claim 2, characterized in that The reaction solvents in steps (A), (B), and (C) are tetrahydrofuran, toluene, acetonitrile, etc., and 25 - 25 g of solvent is added for every 10 g of the total reactants.
4. The method according to claim 2, characterized in that, The reflux reaction time in step (C) is 48 hours; the heating temperature in step (C) is 70 °C.
5. The method according to claim 2, characterized in that, In step (C), the feeding ratio of sodium phenoxide and sodium alcoholate is 1.1 - 1.3 times of the respective stoichiometry.
6. The application of the cyclotriphosphazene derivative described in claim 1 to enhance phosphoric ester compounds, for improving the thermal stability of phosphoric ester compounds.
7. According to the application described in claim 6, the phosphoric ester compounds are trioctyl phosphate, tributyl phosphate, tris(butoxyethyl) phosphate.
8. A method for enhancing the thermal stability of a phosphate compound by the cyclotriphosphazene derivative according to claim 1, characterized in that, Add 20 - 40 wt% of the cyclotriphosphazene derivative collected in step (C) to the phosphoric ester compound; test the improvement of thermal stability by thermogravimetric analysis.
9. The method according to claim 8, characterized in that, In step (E), the temperature range of the thermogravimetric analysis experiment is set to 30 - 600 °C, and the heating rate is controlled at 5 °C / min. When 20 - 40 wt% of the cyclotriphosphazene derivative is added, the thermal decomposition temperature of various phosphoric ester compounds is increased by 20 - 40 °C.