Spirocyclic phosphonates, processes for their preparation and use

Abstract

The application discloses a spirocyclic phosphate ester and a preparation method and application thereof. The structural formula of the spirocyclic phosphate ester is shown in the application. The preparation method of the spirocyclic phosphate ester comprises the following steps: 1) reacting furfurylamine and vanillin to obtain a Schiff base intermediate; 2) reacting the Schiff base intermediate and pentaerythritol bisphosphate dichloride to obtain a flame retardant precursor; and 3) reacting the flame retardant precursor and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to obtain the spirocyclic phosphate ester. The spirocyclic phosphate ester is used as an epoxy resin flame retardant and has the advantages of excellent flame retardant performance, good smoke suppression effect, good thermal stability, good compatibility with the epoxy resin, green environmental protection and the like. Moreover, the preparation method is simple, raw materials are widely sourced, production cost is low, and the spirocyclic phosphate ester is suitable for large-scale industrial production and application.

Description

Technical Field

[0001] This invention relates to the field of flame retardant materials technology, specifically to a spirocyclic phosphate, its preparation method, and its application. Background Technology

[0002] Epoxy resin is a widely used resin, but due to its poor flame retardancy, flame retardants are needed to improve its flame retardant properties. Currently, flame retardants used for epoxy resin can be classified into halogenated flame retardants, inorganic flame retardants, and phosphorus-nitrogen flame retardants. Halogenated flame retardants have high flame retardant efficiency, but they cause significant environmental pollution, greatly limiting their application. Inorganic flame retardants generally have lower flame retardant effects than organic flame retardants, requiring larger addition amounts to achieve the desired effect. However, adding large amounts of inorganic flame retardants can affect the material's mechanical strength and processing performance, and also lead to poor material flowability, impacting processing and product performance. Phosphorus-nitrogen flame retardants do not contain halogen atoms and have high flame retardant efficiency, making them a current research hotspot in the field of flame retardants. However, the flame retardant performance of existing phosphorus-nitrogen flame retardants still needs further improvement, and they are not yet environmentally friendly enough to fully meet the growing demands of practical applications.

[0003] Therefore, it is of great significance to develop a flame retardant with excellent flame retardant properties, good smoke suppression effect, and green environmental protection. Summary of the Invention

[0004] The purpose of this invention is to provide a spirocyclic phosphate, its preparation method, and its application.

[0005] The technical solution adopted in this invention is:

[0006] A spirocyclic phosphate ester, the structural formula of which is as follows:

[0007]

[0008] A method for preparing the spirocyclic phosphate ester as described above includes the following steps:

[0009] 1) The reaction of furfurylamine and vanillin yields...

[0010] 2) Perform The reaction with pentaerythritol diphosphate diphosphonate chloride yields

[0011]

[0012] 3) Perform The reaction with 9,10-dihydro-9oxa-10phosphaphenanthrene-10-oxide yields spirocyclic phosphate.

[0013] Preferably, a method for preparing a spirocyclic phosphate as described above includes the following steps:

[0014] 1) Furfurylamine and vanillin were dispersed in a solvent and reacted, followed by product separation and purification to obtain...

[0015]

[0016] 2) Pentaerythritol diphosphate diphosphonate chloride and an acid-binding agent were dispersed in a solvent and reacted, followed by product separation and purification to obtain...

[0017]

[0018] 3) The reaction was carried out with 9,10-dihydro-9oxa-10phosphaphenanthrene-10-oxide dispersed in a solvent, followed by product separation and purification to obtain spirocyclic phosphate.

[0019] Preferably, the molar ratio of furfurylamine and vanillin in step 1) is 1:1.0 to 1.2.

[0020] Preferably, the solvent in step 1) is at least one of ethanol, methanol, dimethylformamide, and 1,2-dichloroethane.

[0021] Preferably, the reaction in step 1) is carried out at a temperature of 50℃ to 80℃ for a reaction time of 6h to 10h.

[0022] Preferably, step 2) is described The molar ratio of pentaerythritol diphosphate diphosphonate chloride is 2.0 to 2.2:1.

[0023] Preferably, the molar ratio of pentaerythritol diphosphate diphosphonate chloride and acid-binding agent in step 2) is 1:2.5 to 3.0.

[0024] Preferably, the acid-binding agent in step 2) is at least one of triethylamine, pyridine, N,N-diisopropylethylamine, potassium carbonate, and sodium carbonate.

[0025] Preferably, the solvent in step 2) is at least one of acetonitrile, 1,4-dioxane, and 1,2-dichloroethane.

[0026] Preferably, the reaction in step 2) is carried out at a temperature of 70℃ to 90℃ for a reaction time of 12h to 16h.

[0027] Preferably, the reaction in step 2) is carried out in a protective atmosphere.

[0028] Preferably, the protective atmosphere is a nitrogen atmosphere or an argon atmosphere.

[0029] Preferably, step 3) is described The molar ratio of 9,10-dihydro-9oxa-10phosphaphenanthrene-10-oxide (DOPO) is 1:2.0 to 2.5.

[0030] Preferably, the solvent in step 3) is at least one of ethanol, 1,4-dioxane, dimethylformamide, 1,2-dichloroethane, and chloroform.

[0031] Preferably, the reaction in step 3) is carried out at a temperature of 60℃ to 90℃ for a reaction time of 12h to 16h.

[0032] A flame retardant comprising the above-mentioned spirocyclic phosphate ester.

[0033] An epoxy resin composite material comprising the above-mentioned spirocyclic phosphate ester.

[0034] Preferably, the spirocyclic phosphate content in the epoxy resin composite material is 5% to 15% by mass.

[0035] The beneficial effects of this invention are: the spirocyclic phosphate of this invention, when used as an epoxy resin flame retardant, has the advantages of excellent flame retardant performance, good smoke suppression effect, good thermal stability, good compatibility with epoxy resin, and green environmental protection. Moreover, its preparation method is simple, the raw materials are widely available, and the production cost is low, making it suitable for large-scale industrial production and application.

[0036] Specifically:

[0037] 1) The spirocyclic phosphate of the present invention has excellent flame retardant properties when used as an epoxy resin flame retardant (when added to epoxy resin at an amount of 7.5wt% to 15wt%, the LOI can reach 30.0% to 31.1%, and the UL-94 flame retardant rating can reach V-0 level), and has excellent char-forming properties and good smoke suppression effect.

[0038] 2) The spirocyclic phosphate of the present invention has good thermal stability, good compatibility with epoxy resin, and is environmentally friendly, making it suitable for flame retardant applications in epoxy resin.

[0039] 3) The spirocyclic phosphate of the present invention is made from furfurylamine and vanillin as the main raw materials. The raw materials are widely available, and the preparation method is simple and the production cost is low, making it suitable for large-scale industrial production and application. Attached Figure Description

[0040] Figure 1 The image shows the 1H NMR spectrum of the spirocyclic phosphate ester in Example 1.

[0041] Figure 2 This is the mass spectrum of the spirocyclic phosphate ester in Example 1.

[0042] Figure 3The thermogravimetric curves and derivative thermogravimetric curves of the spirocyclic phosphate ester in Example 1 under a nitrogen atmosphere are shown.

[0043] Figure 4 This is a comparison chart of the total smoke release of the epoxy resin composite material and E44 epoxy resin after cone calorimetry testing in Example 3.

[0044] Figure 5 This is a comparison chart of the char formation effects of the epoxy resin composite material and E44 epoxy resin in Example 3 after cone calorimetry testing. Detailed Implementation

[0045] The present invention will be further explained and described below with reference to specific embodiments.

[0046] Example 1:

[0047] A spirocyclic phosphate ester, the preparation method of which is as follows:

[0048] 1) Add 9.7 g (0.1 mol) of furfurylamine and 15.2 g (0.1 mol) of vanillin to 100 mL of ethanol, heat to 60 °C and stir for 6 h, let stand and cool naturally to room temperature to allow solid precipitation, filter, take the solid and wash it three times with ice-cold ethanol to obtain Schiff base intermediate. (Recovery rate: 92.0%)

[0049] The reactions that occur in this step are as follows:

[0050]

[0051] 2) Take 18.5g (0.08mol) of 11.9 g (0.04 mol) of pentaerythritol diphosphate diphosphonate and 14 mL (0.1 mol) of triethylamine were added to 120 mL of acetonitrile. The mixture was purged with nitrogen and heated to 80 °C for 12 h. The acetonitrile was then removed by rotary evaporation. The solid was dissolved in 50 mL of chloroform, washed three times with water, and then the chloroform was removed by rotary evaporation to obtain the flame retardant precursor. (The yield was 88.0%);

[0052] The reactions that occur in this step are as follows:

[0053]

[0054] 3) Take 13.6g (0.02mol) of 8.6 g (0.04 mol) of 9,10-dihydro-9oxa-10phosphaphenanthrene-10-oxide was added to 100 mL of 1,4-dioxane, and the mixture was heated to 60 °C and reacted for 16 h. The 1,4-dioxane was then removed by rotary evaporation. The mixture was then extracted with a chloroform and water system (chloroform:water volume ratio of 2:1). The chloroform layer was then removed by rotary evaporation. The mixture was washed three times with icy ethanol and then dried under vacuum at 70 °C for 16 h to obtain spirocyclic phosphate (light yellow solid, denoted as FSPC; yield 82.3%).

[0055] The reactions that occur in this step are as follows:

[0056]

[0057] Note:

[0058] The preparation method of pentaerythritol diphosphate diphosphonate chloride in this embodiment is as follows:

[0059] 13.6 g of pentaerythritol and 122 mg of 4-dimethylaminopyridine were added to 100 mL of chlorobenzene under nitrogen protection. Then, 28.5 mL of phosphorus oxychloride was slowly added. After the addition was complete, the reaction was carried out for 2 h. The temperature was then raised to 110 °C and reacted overnight until no hydrogen chloride gas was produced in the system. The mixture was then cooled to room temperature, filtered, and the solid was washed three times with dichloromethane. The solid was then dried under vacuum at 70 °C for 12 h to obtain pentaerythritol diphosphate diphosphonate chloride (white solid, designated as SPDPC; yield 81.2%).

[0060] The NMR data for pentaerythritol diphosphate diphosphonate chloride (SPDPC) are as follows:

[0061] 1 H NMR (400MHz, DMSO): δ4.26 (s, 4H), 4.23 (s, 4H);

[0062] 13 C NMR (400MHz, DMSO): δ70.38(s), 36.39(s);

[0063] 31 P NMR (400MHz, DMSO): δ7.32(s).

[0064] The 1H NMR spectrum of spirocyclic phosphate (FSPC) in this embodiment is as follows: Figure 1 As shown, the mass spectrum is as follows Figure 2 As shown, the thermogravimetric curves and derivative thermogravimetric curves in a nitrogen atmosphere are as follows: Figure 3 As shown.

[0065] Depend on Figure 1It can be seen that: c and f are the hydrogens corresponding to all benzene rings in the spirocyclic phosphate structure, g is the hydrogen corresponding to the furan ring, a is the methyl peak corresponding to vanillin, and d is the methylene peak at the benzylic position of the furan ring. This indicates that the spirocyclic phosphate with the expected structure was indeed synthesized in this example.

[0066] Depend on Figure 2 It can be seen that the mass-to-charge ratio of the peak with the highest abundance is 1119, and the mass of the electrons detected by mass spectrometry is 1118, which is consistent with the relative molecular mass of the target flame retardant spirocyclic phosphate.

[0067] Depend on Figure 3 It is known that spirocyclic phosphates begin to decompose rapidly when heated to about 200°C, and eventually about 40% remain.

[0068] An epoxy resin composite material is prepared by the following method:

[0069] Dissolve 5 parts by weight of the above-mentioned spirocyclic phosphate in 4 parts by weight of chloroform, then add it to 100 parts by weight of E44 epoxy resin, heat to 100°C and stir for 20 min, then cool to 90°C and add 25 parts by weight of 4,4-diaminodiphenylmethane (DDM), continue stirring for 5 min, then degas using an oil pump for 3 min and immediately pour into a polytetrafluoroethylene mold preheated to 110°C, then cure at 110°C for 2 h, and then cure at 150°C for 2 h to obtain the epoxy resin composite material (denoted as EP / 5%FSPC).

[0070] According to the test results, the limiting oxygen index (LOI) of the epoxy resin composite material (EP / 5%FSPC) in this embodiment is 29.0%, and the UL-94 flame retardant rating is V-1.

[0071] Note:

[0072] Limiting oxygen index: The test was performed on a VOUCH 5801A oxygen index meter in accordance with “ASTM D2863: Test for minimum oxygen concentration in plastics”. The test specimen was 130mm × 10mm × 4mm in size.

[0073] UL-94 Flame Retardancy Rating: The flame retardancy rating was determined using a VOUCH 5420 horizontal and vertical flame tester in accordance with the UL-94 standard. The test specimen was 130mm × 13mm × 4mm in size.

[0074] Example 2:

[0075] An epoxy resin composite material is prepared by the following method:

[0076] Dissolve 7.5 parts by weight of the spirocyclic phosphate from Example 1 in 6 parts by weight of chloroform, then add it to 100 parts by weight of E44 epoxy resin. Heat to 100°C and stir for 20 minutes, then cool to 90°C and add 25 parts by weight of 4,4-diaminodiphenylmethane (DDM). Continue stirring for 5 minutes, then degas using an oil pump for 3 minutes and immediately pour into a polytetrafluoroethylene mold preheated to 110°C. Cure at 110°C for 2 hours and then at 150°C for 2 hours to obtain the epoxy resin composite material (denoted as EP / 7.5%FSPC).

[0077] According to the test results, the limiting oxygen index (LOI) of the epoxy resin composite material (EP / 7.5% FSPC) in this embodiment is 30.2%, and the UL-94 flame retardant rating is V-1.

[0078] Example 3:

[0079] An epoxy resin composite material is prepared by the following method:

[0080] Ten parts by weight of the spirocyclic phosphate ester from Example 1 were dissolved in eight parts by weight of chloroform, and then added to 100 parts by weight of E44 epoxy resin. The mixture was heated to 100°C and stirred for 20 minutes, then cooled to 90°C and 25 parts by weight of 4,4-diaminodiphenylmethane (DDM) were added. The mixture was stirred for another 5 minutes, then degassed with an oil pump for 3 minutes and immediately poured into a polytetrafluoroethylene mold preheated to 110°C. The mixture was then cured at 110°C for 2 hours and then at 150°C for 2 hours to obtain the epoxy resin composite material (denoted as EP / 10%FSPC).

[0081] According to the test results, the limiting oxygen index (LOI) of the epoxy resin composite material (EP / 10%FSPC) in this embodiment is 31.1%, and the UL-94 flame retardant rating is V-0.

[0082] The comparison chart of the total smoke emission of epoxy resin composite material (EP / 10% FSPC) and E44 epoxy resin (denoted as EP) after cone calorimetry testing in this embodiment is shown below. Figure 4 As shown in the comparison chart of charcoal formation effects, Figure 5 (a is EP; b is EP / 10%FSPC) as shown.

[0083] Depend on Figure 4 It can be seen that after adding FSPC, the total smoke release from the combustion of epoxy resin decreased by about 22%, indicating that FSPC has a good smoke suppression effect.

[0084] Depend on Figure 5 It can be seen that the amount of char produced by the combustion of epoxy resin increases significantly after the addition of FSPC, indicating that FSPC can effectively promote char formation.

[0085] Example 4:

[0086] A spirocyclic phosphate ester, the preparation method of which is as follows:

[0087] 1) Add 9.7 g (0.1 mol) of furfurylamine and 15.2 g (0.1 mol) of vanillin to 100 mL of methanol, heat to 50 °C and stir for 8 h, let stand and cool naturally to room temperature to allow solid precipitation, filter, take the solid and wash it three times with ice-cold ethanol to obtain Schiff base intermediate. (The yield was 91.2%);

[0088] 2) Take 18.5g (0.08mol) of 11.9 g (0.04 mol) of pentaerythritol diphosphate diphosphonate chloride (same as in Example 1) and 15 mL (0.09 mol) of N,N-diisopropylethylamine were added to 120 mL of 1,4-dioxane. The mixture was purged with nitrogen and heated to 80 °C for 12 h. The 1,4-dioxane was then removed by rotary evaporation. The solid was dissolved in 50 mL of chloroform, washed three times with water, and then the chloroform was removed by rotary evaporation to obtain the flame retardant precursor. (The yield was 86.5%);

[0089] 3) Take 13.6g (0.02mol) of 8.6 g (0.04 mol) of 9,10-dihydro-9oxa-10phosphaphenanthrene-10-oxide was added to 100 mL of ethanol, and the mixture was heated to 90 °C and reacted for 16 h. The ethanol was then removed by rotary evaporation, followed by extraction with a chloroform and water system (chloroform:water volume ratio of 2:1). The chloroform layer was then removed by rotary evaporation, washed three times with ice-cold ethanol, and dried under vacuum at 70 °C for 16 h to obtain spirocyclic phosphate (light yellow solid, denoted as FSPC; yield 79.0%).

[0090] An epoxy resin composite material is prepared by the following method:

[0091] Dissolve 5 parts by weight of the above-mentioned spirocyclic phosphate in 4 parts by weight of chloroform, then add it to 100 parts by weight of E44 epoxy resin, heat to 100°C and stir for 25 min, then cool to 90°C and add 25 parts by weight of 4,4-diaminodiphenylmethane (DDM), continue stirring for 5 min, then degas using an oil pump for 3 min and immediately pour into a polytetrafluoroethylene mold preheated to 110°C, then cure at 110°C for 2 h, and then cure at 150°C for 2 h to obtain the epoxy resin composite material (denoted as EP / 5%FSPC).

[0092] According to the test results, the limiting oxygen index (LOI) of the epoxy resin composite material (EP / 5%FSPC) in this embodiment is 29.2%, and the UL-94 flame retardant rating is V-1.

[0093] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A spirophosphonate, characterized by, The structure is as follows:

2. A process for the preparation of a spirophosphonate according to claim 1, characterized in that, Includes the following steps: 1) carrying out a reaction of furfuryl amine and vanillin to obtain 2) performing and pentaerythritol bisphosphate dichlorophosphate to obtain 3) performing and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, to give the spiro phosphonate.

3. The method of claim 2, wherein: In step 1), the molar ratio of furfurylamine and vanillin is 1:1.0 to 1.

2.

4. The production method according to claim 2 or 3, characterized by: The reaction described in step 1) is carried out at a temperature of 50℃ to 80℃ for a reaction time of 6h to 10h.

5. The preparation method according to claim 2, characterized in that: Step 2) said The molar ratio of pentaerythritol bisphosphate dichlorophosphate is 2.0-2.2:

1.

6. The production method according to claim 2 or 5, characterized by: The reaction described in step 2) is carried out at a temperature of 70℃~90℃ for a reaction time of 12h~16h.

7. The preparation method according to claim 2, characterized in that: Step 3) The molar ratio of 9,10-dihydro-9oxa-10phosphaphenanthrene-10-oxide is 1:2.0 to 2.

5.

8. The preparation method according to claim 2 or 7, characterized in that: The reaction described in step 3) is carried out at a temperature of 60℃ to 90℃ for a reaction time of 12h to 16h.

9. A flame retardant, characterized in that, It contains the spirocyclic phosphate as described in claim 1.

10. An epoxy resin composite material, characterized in that, It contains the spirocyclic phosphate as described in claim 1.

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