Lipoic acid-containing modified L-arginine material and preparation method thereof

Abstract

The invention relates to the technical field of high polymer materials, and discloses a modified L-arginine material containing lipoic acid and a preparation method thereof.The modified L-arginine material containing lipoic acid is obtained by adding lipoic acid and modified L-arginine into a stirrer, stirring and blending, stirring, vacuum drying and compression molding. Lipoic acid in the modified L-arginine material containing the lipoic acid has a good antibacterial effect, and growth of staphylococcus aureus is inhibited. Phosphorus in the modified L-arginine can generate polyphosphoric acid and metaphosphoric acid which are high in dehydration property during combustion, and the polyphosphoric acid and the metaphosphoric acid are not prone to volatilization and can form a compact protective layer on the surface of the coating, so that the flame-retardant effect is achieved; guanidyl in the L-arginine and phosphorus form a P-N flame-retardant system, so that a relatively good flame-retardant effect is achieved; benzoxazine in the modified L-arginine can form a heat-resistant phenolic resin structure at a high temperature, so that the modified L-arginine has a relatively good flame-retardant effect.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, in particular to a modified L-arginine material containing thioctic acid and a preparation method thereof. Background Art

[0002] L-arginine itself does not have flame retardant properties, which greatly limits its application in the field of materials. Therefore, how to avoid this phenomenon is the key to solving the problem. Benzoxazine is a class of benzo-condensed ring compounds containing nitrogen and oxygen six-membered heterocyclic rings, which has good heat resistance and is widely used in materials, automobile industry and other fields. It is applied in the present invention to improve the flame retardant effect of its materials.

[0003] For example, the document "Preparation and Performance Study of Phosphorus-Based Flame-Retardant Waterborne Polyurethane" reports that a new type of phosphorus-based flame retardant was synthesized using bisphenol fluorene (BPFL) and phenylphosphonyl chloride (BPOD) as raw materials, which has good flame retardant effect. The present invention introduces flame retardant materials containing phosphorus elements by polymerization. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the deficiencies of the prior art, the present invention provides a modified L-arginine material containing lipoic acid and a preparation method thereof, which has good antibacterial and flame retardant effects.

[0006] (II) Technical solution

[0007] To achieve the above object, the present invention provides the following technical solution: a modified L-arginine material containing lipoic acid, comprising the following weight components: 0.3-0.5 weight parts of lipoic acid and 3-5 weight parts of modified L-arginine.

[0008] Furthermore, the preparation method of the modified L-arginine is:

[0009] Step 1: Add 5,5-dimethyl-1,3-dioxahexane phosphoryl chloride and pyridine catalyst to 1,4-dioxane solvent under ice bath, stir to dissolve, continue to add L-arginine, react at 30-45°C for 5-7h, distill under reduced pressure after reaction, wash with n-hexane, and recrystallize the crude product from ethanol to obtain dioxahexane phosphoramido arginine;

[0010] Step 2: Add dioxahexane phosphoramido arginine and diethanol acrylamide to N,N-dimethylformamide solvent, stir and mix, continue to add p-toluenesulfonic acid catalyst, react at 80-95° C. for 7-8 hours, and then distill under reduced pressure and wash to obtain alkenyl phosphorus arginine;

[0011] Step 3: Under a nitrogen atmosphere, add 5-6 g of bisphenol fluorene and 1-1.5 mL of triethylamine to 45-55 mL of dichloromethane solvent, stir at 8-10° C. until fully dissolved, then continue to add 1.65-1.67 g of phenylphosphoryl dichloride, stir to react, and obtain a phenol-based flame retardant after completion;

[0012] Step 4: Add 1.3-2 g of allylamine and an aqueous solution containing 1.5-2.4 g of formaldehyde to a 1,4-dioxane solvent, stir at 2-4° C. for 1-3 h, then add 4.1-5.6 g of a phenol-based flame retardant, stir at 80-90° C. for a cyclization reaction, perform vacuum distillation after the reaction, and recrystallize from ethanol to obtain an olefinated benzoxazine;

[0013] Step 5: In a nitrogen atmosphere, add alkenyl benzoxazine and alkenyl phosphorus-containing arginine to N,N-dimethylformamide solvent, and then continue to add initiator azobisisobutyronitrile, heat to 70-80°C and reflux for 5-7h, and after the reaction, distill under reduced pressure, filter, and wash to obtain modified L-arginine.

[0014] In the above reaction process, the acyl chloride group in 5,5-dimethyl-1,3-dioxahexanephosphoryl chloride undergoes an amidation reaction with the amino group in L-arginine to introduce a carboxyl group, and then undergoes an esterification reaction with diethanol acrylamide to introduce an alkenyl group; bisphenol fluorene reacts with the chlorine in phenylphosphoryl dichloride to introduce a phenolic hydroxyl group to obtain a phenol-based flame retardant, and then continues to react with an aqueous solution of allylamine and formaldehyde to obtain an alkenylated benzoxazine; the alkenylated benzoxazine and alkenyl phosphorus-containing arginine are polymerized to obtain modified L-arginine.

[0015] Furthermore, in the step 1, the mass ratio of 5,5-dimethyl-1,3-dioxahexanephosphoryl chloride, pyridine catalyst and L-arginine is 2.3-2.6 g: 0.01-0.02 g: 2.2-2.4 g.

[0016] Furthermore, in the step 2, the mass ratio of dioxahexane phosphoramido arginine, diethanol acrylamide, and p-toluenesulfonic acid catalyst is 2.4-3g:1.12-1.35g:0.021-0.026g.

[0017] Furthermore, the stirring reaction time in step three is 8-10 hours.

[0018] Furthermore, the cyclization reaction time in step 4 is 10-13h.

[0019] Furthermore, in the step 5, the mass ratio of alkenylated benzoxazine, alkenyl phosphorus-containing arginine, and azobisisobutyronitrile is 1 g: 0.8-1.1 g: 0.012-0.014 g.

[0020] Furthermore, the preparation method of the modified L-arginine material containing lipoic acid is: adding lipoic acid and modified L-arginine into a stirrer, stirring and blending, stirring for 10-15 minutes, vacuum drying, and compression molding to obtain the modified L-arginine material containing lipoic acid.

[0021] (III) Beneficial technical effects

[0022] The invention obtains the modified L-arginine material containing lipoic acid by adding lipoic acid and modified L-arginine into a stirrer, stirring and blending, stirring, vacuum drying, and compression molding.

[0023] The lipoic acid in the modified L-arginine material containing lipoic acid has good antibacterial effect and inhibits the growth of Staphylococcus aureus. The phosphorus element in the modified L-arginine can generate polyphosphoric acid and metaphosphoric acid with strong dehydration when burning. Since polyphosphoric acid and metaphosphoric acid are not easy to volatilize, they can form a dense protective layer on the surface of the coating, thus playing a flame retardant effect; the guanidine group in L-arginine will form a PN flame retardant system with the phosphorus element, which has a good flame retardant effect; the benzoxazine in the modified L-arginine will form a heat-resistant phenolic resin structure at high temperature, which makes it have a good flame retardant effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is the reaction formula of alkenylphosphoarginine.

[0025] Figure 2 This is the H NMR spectrum of alkenylphosphoarginine.

[0026] Figure 3 This is the inhibition zone diameter test chart. DETAILED DESCRIPTION

[0027] At 0°C, add 300 mL of dichloromethane, 19 mmol of diethanolamine, 67 mmol of pyridine and 57 mmol of acryloyl chloride to a flask, react for 15 h in a nitrogen atmosphere, concentrate the solution, add 30 mL of methanol and 20 mL of a saturated sodium carbonate solution, stir at room temperature for 3 h, then add dichloromethane and water for extraction, and after the reaction of the extract product, separate it by column chromatography, using a solution of chloroform and methanol in a volume ratio of 10:1 as an eluent to obtain diethanolacrylamide.

[0028] Example 1

[0029] Step 1: Add 2.3 g of 5,5-dimethyl-1,3-dioxahexane phosphoryl chloride and 0.01 g of pyridine catalyst to 30 mL of 1,4-dioxane solvent under an ice bath, stir to dissolve, continue to add 2.2 g of L-arginine, react at 30° C. for 5 h, distill under reduced pressure after the reaction, wash with n-hexane, and recrystallize the crude product from ethanol to obtain dioxahexane phosphoramido arginine;

[0030] Step 2: Add 2.4 g of dioxahexane phosphoramido arginine and 1.12 g of diethanol acrylamide to 25 mL of N,N-dimethylformamide solvent, stir and mix, continue to add 0.021 g of p-toluenesulfonic acid catalyst, react at 80° C. for 7 h, and then distill under reduced pressure and wash to obtain alkenyl phosphorus arginine;

[0031] Step 3: Under a nitrogen atmosphere, add 5 g of bisphenol fluorene and 1 mL of triethylamine to 45 mL of dichloromethane solvent, stir at 8 ° C until fully dissolved, then continue to add 1.65 g of phenylphosphoryl dichloride, stir and react for 8 hours, and then obtain a phenol-based flame retardant;

[0032] Step 4: Add 1.3 g of allylamine and an aqueous solution containing 1.5 g of formaldehyde to 25 mL of 1,4-dioxane solvent, stir at 2°C for 1 hour, then add 4.1 g of phenol-based flame retardant, stir at 80°C for 10 hours for cyclization reaction, distill under reduced pressure after the reaction, and recrystallize in ethanol to obtain olefinated benzoxazine;

[0033] Step 5: In a nitrogen atmosphere, 1 g of alkenyl benzoxazine and 0.8 g of alkenyl phosphorus-containing arginine were added to 15 mL of N,N-dimethylformamide solvent, and then 0.012 g of initiator azobisisobutyronitrile was added thereto, and the temperature was raised to 70° C. and refluxed for reaction for 5 h. After the reaction, the mixture was distilled under reduced pressure, filtered, and washed to obtain modified L-arginine;

[0034] Step 6: Add 0.3 parts by weight of lipoic acid and 3 parts by weight of modified L-arginine into a stirrer, stir and blend, stir for 10 minutes, vacuum dry, and compression mold to obtain a modified L-arginine material containing lipoic acid.

[0035] Example 2

[0036] Step 1: Add 2.6 g of 5,5-dimethyl-1,3-dioxahexane phosphoryl chloride and 0.02 g of pyridine catalyst to 50 mL of 1,4-dioxane solvent under an ice bath, stir to dissolve, continue to add 2.4 g of L-arginine, react at 45° C. for 7 h, distill under reduced pressure after the reaction, wash with n-hexane, and recrystallize the crude product from ethanol to obtain dioxahexane phosphoramido arginine;

[0037] Step 2: Add 3 g of dioxahexane phosphoramido arginine and 1.35 g of diethanol acrylamide to 35 mL of N,N-dimethylformamide solvent, stir and mix, continue to add 0.026 g of p-toluenesulfonic acid catalyst, react at 95° C. for 8 h, and then distill under reduced pressure and wash to obtain alkenyl phosphorus arginine;

[0038] Step 3: Under a nitrogen atmosphere, add 6 g of bisphenol fluorene and 1.5 mL of triethylamine to 55 mL of dichloromethane solvent, stir at 10°C until fully dissolved, then continue to add 1.67 g of phenylphosphoryl dichloride, stir and react for 10 hours, and after completion, obtain a phenol-based flame retardant;

[0039] Step 4: Add 2 g of allylamine and an aqueous solution containing 2.4 g of formaldehyde to 30 mL of 1,4-dioxane solvent, stir at 4°C for 3 h, then add 5.6 g of phenol-based flame retardant, stir at 90°C for cyclization reaction for 13 h, distill under reduced pressure after the reaction, and recrystallize in ethanol to obtain olefinated benzoxazine;

[0040] Step 5: In a nitrogen atmosphere, 1 g of alkenyl benzoxazine and 1.1 g of alkenyl phosphorus-containing arginine were added to 18 mL of N,N-dimethylformamide solvent, and then 0.014 g of initiator azobisisobutyronitrile was added thereto, and the temperature was raised to 80° C. and refluxed for reaction for 7 h. After the reaction, the mixture was distilled under reduced pressure, filtered, and washed to obtain modified L-arginine;

[0041] Step 6: Add 0.5 parts by weight of lipoic acid and 5 parts by weight of modified L-arginine into a stirrer, stir and blend, stir for 15 minutes, vacuum dry, and compression mold to obtain a modified L-arginine material containing lipoic acid.

[0042] Example 3

[0043] Step 1: Add 2.5 g of 5,5-dimethyl-1,3-dioxahexane phosphoryl chloride and 0.015 g of pyridine catalyst to 40 mL of 1,4-dioxane solvent under an ice bath, stir to dissolve, continue to add 2.3 g of L-arginine, react at 40° C. for 6 h, distill under reduced pressure after the reaction, wash with n-hexane, and recrystallize the crude product from ethanol to obtain dioxahexane phosphoramido arginine;

[0044] Step 2: Add 2.6 g of dioxahexane phosphoramido arginine and 1.22 g of diethanol acrylamide to 30 mL of N,N-dimethylformamide solvent, stir and mix, continue to add 0.023 g of p-toluenesulfonic acid catalyst, react at 85° C. for 8 h, and then distill under reduced pressure and wash to obtain alkenyl phosphorus arginine;

[0045] Step 3: Under a nitrogen atmosphere, add 5.5 g of bisphenol fluorene and 1 mL of triethylamine to 50 mL of dichloromethane solvent, stir at 9 ° C until fully dissolved, then continue to add 1.66 g of phenylphosphoryl dichloride, stir and react for 9 hours, and then obtain a phenol-based flame retardant;

[0046] Step 4: Add 1.6 g of allylamine and an aqueous solution containing 2.1 g of formaldehyde to 28 mL of 1,4-dioxane solvent, stir at 3°C ​​for 2 h, then add 5.3 g of phenol-based flame retardant, stir at 85°C for 12 h for cyclization reaction, distill under reduced pressure after the reaction, and recrystallize from ethanol to obtain olefinated benzoxazine;

[0047] Step 5: In a nitrogen atmosphere, 1 g of alkenyl benzoxazine and 0.9 g of alkenyl phosphorus-containing arginine were added to 17 mL of N,N-dimethylformamide solvent, and then 0.013 g of initiator azobisisobutyronitrile was added thereto, and the temperature was raised to 75° C. and refluxed for 6 h. After the reaction, the mixture was distilled under reduced pressure, filtered, and washed to obtain modified L-arginine;

[0048] Step 6: Add 0.4 parts by weight of lipoic acid and 4 parts by weight of modified L-arginine into a stirrer, stir and blend, stir for 12 minutes, vacuum dry, and compression mold to obtain a modified L-arginine material containing lipoic acid.

[0049] Example 4

[0050] Step 1: Add 2.3 g of 5,5-dimethyl-1,3-dioxahexane phosphoryl chloride and 0.01 g of pyridine catalyst to 30 mL of 1,4-dioxane solvent under an ice bath, stir to dissolve, continue to add 2.2 g of L-arginine, react at 30° C. for 5 h, distill under reduced pressure after the reaction, wash with n-hexane, and recrystallize the crude product from ethanol to obtain dioxahexane phosphoramido arginine;

[0051] Step 2: Add 2.4 g of dioxahexane phosphoramido arginine and 1.12 g of diethanol acrylamide to 25 mL of N,N-dimethylformamide solvent, stir and mix, continue to add 0.021 g of p-toluenesulfonic acid catalyst, react at 80° C. for 7 h, and then distill under reduced pressure and wash to obtain alkenyl phosphorus arginine;

[0052] Step 3: Under a nitrogen atmosphere, add 6 g of bisphenol fluorene and 1.5 mL of triethylamine to 55 mL of dichloromethane solvent, stir at 10°C until fully dissolved, then continue to add 1.67 g of phenylphosphoryl dichloride, stir and react for 10 hours, and after completion, obtain a phenol-based flame retardant;

[0053] Step 4: Add 2 g of allylamine and an aqueous solution containing 2.4 g of formaldehyde to 30 mL of 1,4-dioxane solvent, stir at 4°C for 3 h, then add 5.6 g of phenol-based flame retardant, stir at 90°C for cyclization reaction for 13 h, distill under reduced pressure after the reaction, and recrystallize in ethanol to obtain olefinated benzoxazine;

[0054] Step 5: In a nitrogen atmosphere, 1 g of alkenyl benzoxazine and 0.9 g of alkenyl phosphorus-containing arginine were added to 17 mL of N,N-dimethylformamide solvent, and then 0.013 g of initiator azobisisobutyronitrile was added thereto, and the temperature was raised to 75° C. and refluxed for 6 h. After the reaction, the mixture was distilled under reduced pressure, filtered, and washed to obtain modified L-arginine;

[0055] Step 6: Add 0.4 parts by weight of lipoic acid and 4 parts by weight of modified L-arginine into a stirrer, stir and blend, stir for 12 minutes, vacuum dry, and compression mold to obtain a modified L-arginine material containing lipoic acid.

[0056] Example 5

[0057] Step 1: Add 2.6 g of 5,5-dimethyl-1,3-dioxahexane phosphoryl chloride and 0.02 g of pyridine catalyst to 50 mL of 1,4-dioxane solvent under an ice bath, stir to dissolve, continue to add 2.4 g of L-arginine, react at 45° C. for 7 h, distill under reduced pressure after the reaction, wash with n-hexane, and recrystallize the crude product from ethanol to obtain dioxahexane phosphoramido arginine;

[0058] Step 2: Add 3 g of dioxahexane phosphoramido arginine and 1.35 g of diethanol acrylamide to 35 mL of N,N-dimethylformamide solvent, stir and mix, continue to add 0.026 g of p-toluenesulfonic acid catalyst, react at 95° C. for 8 h, and then distill under reduced pressure and wash to obtain alkenyl phosphorus arginine;

[0059] Step 3: Under a nitrogen atmosphere, add 5.5 g of bisphenol fluorene and 1 mL of triethylamine to 50 mL of dichloromethane solvent, stir at 9 ° C until fully dissolved, then continue to add 1.66 g of phenylphosphoryl dichloride, stir and react for 9 hours, and then obtain a phenol-based flame retardant;

[0060] Step 4: Add 1.6 g of allylamine and an aqueous solution containing 2.1 g of formaldehyde to 28 mL of 1,4-dioxane solvent, stir at 3°C ​​for 2 h, then add 5.3 g of phenol-based flame retardant, stir at 85°C for 12 h for cyclization reaction, distill under reduced pressure after the reaction, and recrystallize from ethanol to obtain olefinated benzoxazine;

[0061] Step 5: In a nitrogen atmosphere, 1 g of alkenyl benzoxazine and 0.8 g of alkenyl phosphorus-containing arginine were added to 15 mL of N,N-dimethylformamide solvent, and then 0.012 g of initiator azobisisobutyronitrile was added thereto, and the temperature was raised to 70° C. and refluxed for reaction for 5 h. After the reaction, the mixture was distilled under reduced pressure, filtered, and washed to obtain modified L-arginine;

[0062] Step 6: Add 0.3 parts by weight of lipoic acid and 3 parts by weight of modified L-arginine into a stirrer, stir and blend, stir for 10 minutes, vacuum dry, and compression mold to obtain a modified L-arginine material containing lipoic acid.

[0063] Comparative Example 1

[0064] Compared with Example 5, this comparative example differs in that dioxahexyl phosphoramido arginine is used instead of modified L-arginine.

[0065] Comparative Example 2

[0066] The difference between this comparative example and Example 5 is that a phenol-based flame retardant is used instead of modified L-arginine.

[0067] The modified L-arginine material containing lipoic acid was tested for its limiting oxygen index using an oxygen index meter, and its combustion grade using a horizontal and vertical combustion instrument. The test results are shown in Table 1.

[0068] Table 1: Flame retardancy tests.

[0069]

[0070]

[0071] It can be seen from Table 1 that Examples 1-5 of the present invention and Comparative Examples 1-2 have good flame retardant effects.

[0072] A Staphylococcus aureus liquid with a concentration of 2×108 CFU / mL was added to a sterilized culture dish as the test strain, and then solid agar medium was added and dissolved, cooled to 45°C, and then poured into the culture dish, 20 mL was poured into each plate with an inner diameter of 10 cm, and then the materials of the embodiments of the present invention and the comparative example (with a diameter of 3 cm and a thickness of 1 mm) were placed on the culture plate, and cultured in a constant temperature incubator for 12 hours at a temperature of 37°C. After culture, the diameter of the inhibition zone was measured. The test results are as follows: Figure 3 .

[0073] Depend on Figure 3 It can be seen that Examples 1-5 of the present invention and Comparative Examples 1-2 have good antibacterial effects.

[0074] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A modified L-arginine material containing lipoic acid, characterized in that, The invention comprises the following components by weight: 0.3-0.5 parts by weight of lipoic acid and 3-5 parts by weight of modified L-arginine.

2. The modified L-arginine material containing lipoic acid according to claim 1, characterized in that, The preparation method of the modified L-arginine is: Step 1: Add 5,5-dimethyl-1,3-dioxahexane phosphoryl chloride and pyridine catalyst to 1,4-dioxane solvent under ice bath, stir to dissolve, continue to add L-arginine, react at 30-45°C for 5-7h, distill under reduced pressure after reaction, wash with n-hexane, and recrystallize the crude product from ethanol to obtain dioxahexane phosphoramido arginine; Step 2: Add dioxahexane phosphoramido arginine and diethanol acrylamide to N,N-dimethylformamide solvent, stir and mix, continue to add p-toluenesulfonic acid catalyst, react at 80-95° C. for 7-8 hours, and then distill under reduced pressure and wash to obtain alkenyl phosphorus arginine; Step 3: Under a nitrogen atmosphere, add 5-6 g of bisphenol fluorene and 1-1.5 mL of triethylamine to 45-55 mL of dichloromethane solvent, stir at 8-10° C. until fully dissolved, then continue to add 1.65-1.67 g of phenylphosphoryl dichloride, stir to react, and obtain a phenol-based flame retardant after completion; Step 4: Add 1.3-2 g of allylamine and an aqueous solution containing 1.5-2.4 g of formaldehyde to a 1,4-dioxane solvent, stir at 2-4° C. for 1-3 h, then add 4.1-5.6 g of a phenol-based flame retardant, stir at 80-90° C. for a cyclization reaction, perform vacuum distillation after the reaction, and recrystallize from ethanol to obtain an olefinated benzoxazine; Step 5: In a nitrogen atmosphere, add alkenyl benzoxazine and alkenyl phosphorus-containing arginine to N,N-dimethylformamide solvent, and then continue to add initiator azobisisobutyronitrile, heat to 70-80°C and reflux for 5-7h, and after the reaction, distill under reduced pressure, filter, and wash to obtain modified L-arginine.

3. The modified L-arginine material containing lipoic acid according to claim 2, characterized in that, In the step 1, the mass ratio of 5,5-dimethyl-1,3-dioxahexanephosphoryl chloride, pyridine catalyst and L-arginine is 2.3-2.6 g: 0.01-0.02 g: 2.2-2.4 g.

4. The modified L-arginine material containing lipoic acid according to claim 2, characterized in that, In the step 2, the mass ratio of dioxahexane phosphoramido arginine, diethanol acrylamide and p-toluenesulfonic acid catalyst is 2.4-3g:1.12-1.35g:0.021-0.026g.

5. The modified L-arginine material containing lipoic acid according to claim 2, characterized in that, The stirring reaction time in step 3 is 8-10 hours.

6. The modified L-arginine material containing lipoic acid according to claim 2, characterized in that, The cyclization reaction time in step 4 is 10-13h.

7. The modified L-arginine material containing lipoic acid according to claim 2, characterized in that, In the step 5, the mass ratio of alkenyl benzoxazine, alkenyl phosphorus-containing arginine, and azobisisobutyronitrile is 1 g: 0.8-1.1 g: 0.012-0.014 g.

8. A method for preparing a modified L-arginine material containing lipoic acid as claimed in any one of claims 1 to 7, characterized in that: The preparation method of the modified L-arginine material containing lipoic acid is as follows: adding lipoic acid and modified L-arginine into a stirrer, stirring and blending, stirring for 10-15 minutes, vacuum drying, and compression molding to obtain the modified L-arginine material containing lipoic acid.

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