Green synthesis method for using phytic acid derived copper, zinc and tin chelate as flame inhibitor

Abstract

The invention discloses a green synthesis method of a phytic acid-derived metal chelate as a flame inhibitor. The green synthesis method comprises the following steps: S1, preparing a metal compound solution with a specific concentration; s2, preparing a phytic acid solution with an adaptive concentration, fully and uniformly mixing the phytic acid solution with the solution obtained in the step S1, and then carrying out magnetic stirring operation; s3, introducing a sodium hydroxide solution with a specific concentration into the mixed solution, and accurately regulating and controlling the pH value of the solution; s4, in an inert gas protection environment, performing hydrothermal reaction on the solution obtained in the step S3; and S5, after the reaction in the step S4 is finished, drying the product, and washing the precipitate to finally obtain the target chelate material. The phytic acid chelate prepared by the invention is excellent in flame inhibition performance, and can be widely applied to the fields of fire extinguishing agents and flame-retardant materials.

Description

Technical Field

[0001] This invention relates to a green synthesis method for using phytic acid-derived copper, zinc, and tin chelates as flame suppressants, and belongs to the field of flame suppressant preparation. Background Technology

[0002] Fires pose a significant threat to personal safety, property security, and even the ecological environment. Using flame suppressants can significantly reduce the damage caused by such disasters. In recent years, with the growing global awareness of environmental protection, traditional halon-based flame suppressants have been completely banned due to their ozone-depleting properties. Currently, most mainstream products on the market are phosphorus-based flame suppressants; however, their precursor—phosphate rock—is not only consumed extremely quickly but also significantly limited by geographical distribution, and has been regarded as a strategically critical raw material. Against this backdrop, the search for environmentally friendly and highly efficient new flame suppressants is particularly urgent.

[0003] Phytic acid (PA), as a bio-based flame retardant monomer, is an ideal choice for synthesizing bio-based flame inhibitors due to its high phosphorus content (up to 28 wt%), good modifiability, non-toxicity, and renewability. Nevertheless, due to the complexity of compound modification techniques and the challenge of balancing cost-effectiveness, the application of phytic acid in the field of flame retardation is still in its early stages of development, and the types of inhibitors derived from it are relatively limited.

[0004] There is an urgent need to develop a method for preparing flame suppressants that can effectively replace ore phosphorus sources and overcome the limitations of existing technologies. Summary of the Invention

[0005] To address the technical bottlenecks and shortcomings of the prior art, this invention aims to provide a green synthesis method for phytic acid-derived copper, zinc, and tin chelates as flame suppressants. This method exhibits significant environmental friendliness, low raw material costs, and a highly controllable preparation process, enabling a high yield of finished products. The phytic acid chelates obtained through this process can be widely used in the fields of fire extinguishing agents and flame retardant materials.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is: a green synthesis method for using phytic acid-derived metal chelates as flame suppressants, comprising the following steps:

[0007] S1. Prepare a metal compound solution of a specific concentration;

[0008] S2. Prepare a phytic acid solution of appropriate concentration, mix it thoroughly with the solution obtained in step S1, and then perform magnetic stirring.

[0009] S3. Introduce a sodium hydroxide solution of a specific concentration into the above mixed solution to precisely control the pH value of the solution;

[0010] S4. In an inert gas environment, a hydrothermal reaction is carried out on the solution obtained in step S3;

[0011] S5. After the reaction in step S4 is completed, the product is dried and the precipitate is washed to finally obtain the target chelate material.

[0012] Preferably, in step S1, the concentration of the metal compound solution is controlled in the range of 0.01~0.5 mol / L.

[0013] Preferably, in step S1, the metal compound is selected from copper sulfate pentahydrate, zinc sulfate heptahydrate, anhydrous tin tetrachloride, and any one of their similar compounds.

[0014] Preferably, the solvents used in steps S1 and S2 are deionized water, ethanol, or combinations thereof.

[0015] Preferably, in step S2, the concentration of the phytic acid solution is controlled at 0.002~0.5 mol / L.

[0016] Preferably, in step S3, the pH value of the mixed solution is adjusted to 6.5~8.5.

[0017] Preferably, in step S3, the concentration of the sodium hydroxide solution is 0.1 mol / L.

[0018] Preferably, in step S4, the inert gas used is argon.

[0019] Preferably, in step S4, the hydrothermal reaction temperature is set to 50~90℃, and the reaction time is controlled to 6~18 h.

[0020] Preferably, in step S5, the temperature of the drying oven is set to 70~120℃, and the drying time is maintained for 3~12 hours.

[0021] The beneficial effects of this invention are as follows: This invention selects phytic acid (PA) as an organic ligand to precisely chelate inorganic metal elements with potential flame-suppressing properties—copper (Cu), zinc (Zn), and tin (Sn)—and then designs three novel phytic acid-derived inhibitor formulations: Cu-PMC, Zn-PMC, and Sn-PMC. Relying on the synergistic flame-suppressing effect between the bio-based phosphorus source and the metal composite components, these three chelates exhibit excellent flame-suppressing performance, showing significant advantages over commercial flame inhibitors such as ammonium dihydrogen phosphate, with improvements exceeding 50%.

[0022] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0023] Figure 1 The TG and DTG curves are for (a) Cu-PMC, (b) Zn-PMC, and (c) Sn-PMC.

[0024] Figure 2 SEM images of (a) Cu-PMC, (b) Zn-PMC, and (c) Sn-PMC at different magnifications.

[0025] Figure 3 TEM images of (a) Cu-PMC, (b) Zn-PMC, and (c) Sn-PMC at different magnifications.

[0026] Figure 4 The main elemental distribution of Cu-PMC.

[0027] Figure 5 The main elemental distribution of Zn-PMC.

[0028] Figure 6 The main elemental distribution of Sn-PMC. Detailed Implementation

[0029] The technical solution of the present invention will be explained in detail below with reference to specific embodiments.

[0030] Example 1

[0031] 100 mL of a 0.05 mol / L copper sulfate solution was prepared, and 6 g of a 0.005 mmol / L phytic acid solution was added. The mixture was then magnetically stirred for 30 min. Next, a 0.1 mol / L NaOH solution was added to adjust the pH to 7-8. A hydrothermal reaction was then carried out at 70 °C for 12 h. After the reaction, excess moisture was removed using a vacuum oven, and the precipitate was repeatedly washed with deionized water. Finally, it was vacuum dried overnight at room temperature to obtain the Cu-PMC sample.

[0032] Example 2

[0033] 100 mL of a 0.05 mol / L zinc sulfate solution was prepared, and 6 g of a 0.005 mmol / L phytic acid solution was added. After magnetic stirring for 30 min, a 0.1 mol / L NaOH solution was added to precisely adjust the pH of the system to 7–8. Subsequently, a hydrothermal reaction was carried out at 70 °C for 12 h. After the reaction was complete, excess water was removed using a vacuum oven, the precipitate was washed multiple times with deionized water, and then vacuum dried overnight at room temperature to obtain the Zn-PMC sample.

[0034] Example 3

[0035] 100 mL of a 0.05 mol / L tin tetrachloride solution was prepared, and 11 g of a 0.005 mmol / L phytic acid solution was added. After magnetic stirring for 30 min, a 0.1 mol / L NaOH solution was added to adjust the pH of the system to 7–8. Subsequently, a hydrothermal reaction was carried out at 70 °C for 12 h. After the reaction was complete, excess water was removed by vacuum drying, the precipitate was repeatedly washed with deionized water, and finally vacuum dried overnight at room temperature, successfully obtaining the Sn-PMC sample.

[0036] The cellulose bed method (Fire Saf. J. 153 (2025) 104382, J. Solid State Chem. 309 (2022) 122975) was used as the performance carrier for Cu-PMC, Zn-PMC, and Sn-PMC. The flame suppression performance of the three inhibitors was characterized by oxygen index, UL-94 vertical burning test, and thermogravimetric analysis. In the oxygen index and UL-94 vertical burning test, the currently mainstream commercial phosphorus-based inhibitor, ammonium dihydrogen phosphate (ADP), was used as a control. The adsorption concentration of the inhibitor on the cellulose bed was controlled at low (1×10⁻⁴ mol / g), medium (3×10⁻⁴ mol / g), and high (6×10⁻⁴ mol / g).

[0037] Table 1 shows the oxygen index and vertical combustion test results for the examples and comparative examples.

[0038]

[0039] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the scope of protection of the present invention in any way, and all technical solutions obtained by equivalent substitution or other means fall within the scope of protection of the present invention. Parts not covered in this invention are the same as or can be implemented using existing technology.

Claims

1. A green synthetic method for using phytic acid-derived metal chelates as flame suppressants, characterized in that, Includes the following steps: S1. Prepare a metal compound solution of a specific concentration; S2. Prepare a phytic acid solution of appropriate concentration, mix it thoroughly with the solution obtained in step S1, and then perform magnetic stirring. S3. Introduce a sodium hydroxide solution of a specific concentration into the above mixed solution to precisely control the pH value of the solution; S4. In an inert gas environment, a hydrothermal reaction is carried out on the solution obtained in step S3; S5. After the reaction in step S4 is completed, the product is dried and the precipitate is washed to finally obtain the target chelate material.

2. A green synthetic method for using plant acid-derived metal chelates as flame suppressants according to claim 1, characterized in that, In step S1, the concentration of the metal compound solution is controlled within the range of 0.01~0.5 mol / L.

3. A green synthetic method for using plant acid-derived metal chelates as flame suppressants according to claim 1, characterized in that, In step S1, the metal compound is selected from copper sulfate pentahydrate, zinc sulfate heptahydrate, anhydrous tin tetrachloride, and any one of their similar compounds.

4. A green synthetic method for using plant acid-derived metal chelates as flame suppressants according to claim 1, characterized in that, The solvents used in steps S1 and S2 are deionized water, ethanol, and combinations thereof.

5. A green synthetic method for using phytic acid-derived metal chelates as flame suppressants according to claim 1, characterized in that, In step S2, the concentration of the phytic acid solution is controlled at 0.002~0.5 mol / L.

6. A green synthetic method for using acid-derived metal chelates as flame suppressants according to claim 1, characterized in that, In step S3, the pH value of the mixed solution is adjusted to 6.5~8.

5.

7. A green synthetic method for using plant acid-derived metal chelates as flame suppressants according to claim 1, characterized in that, In step S3, the concentration of the sodium hydroxide solution is 0.1 mol / L.

8. A green synthetic method for using acid-derived metal chelates as flame suppressants according to claim 1, characterized in that, In step S4, the inert gas used is argon.

9. A green synthetic method for using plant acid-derived metal chelates as flame suppressants according to claim 1, characterized in that, In step S4, the hydrothermal reaction temperature is set to 50~90℃, and the reaction time is controlled to 6~18 h.

10. A green synthetic method for using phytic acid-derived metal chelates as flame suppressants according to claim 1, characterized in that, In step S5, the temperature of the drying oven is set to 70~120℃, and the drying time is maintained at 3~12 h.

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