A tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine compound and a synthesis method thereof

Abstract

The present invention discloses a tris(3,5-dimethyl-4-nitrile phenoxy) triazine compound, characterized in that it has the chemical structural formula shown in (I): A tris(3,5-dimethyl-4-nitrile phenoxy) triazine compound, characterized in that it has the chemical structural formula shown in (I): The tris(3,5-dimethyl-4-nitrile phenoxy) triazine compound of the present invention can be stably present at room temperature (20-30° C.), and is easy to preserve and store for a long time. The molecular structure contains three CNO groups, which is more widely applicable in olefin-based polymer cross-linking systems, can undergo cycloaddition reactions with compounds containing unsaturated double bonds, and can be applied to the field of non-isocyanate room temperature curing molding of solid propellants.

Description

Technical Field

[0001] The invention belongs to the field of organic compound preparation, and specifically relates to a tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine compound and a synthesis method thereof. Background Art

[0002] Nitrile oxides are organic compounds in which the nitrile group (-CNO) is directly connected to the carbon atom on the molecule. Since -CNO, as a generalized 1,3-dipole, can undergo cycloaddition reactions with dipolephilic compounds containing unsaturated double bonds (olefin groups) or triple bonds (alkyne groups, cyano groups), and the reaction does not require metal catalysis and does not generate by-products, nitrile oxides have been widely used in the fields of biochemistry, medicinal chemistry, and polymer science. Nitrile oxides containing two or more -CNO groups in their molecular structure are a common class of olefin-containing polymer crosslinkers. As curing agents, they participate in crosslinking reactions with the advantages of mild reaction conditions, wide environmental adaptability, no by-product generation, and green and no heavy metal pollution. However, most low-level aliphatic and aromatic nitrile oxide curing agents are unstable at room temperature and are prone to dimerization or isomerization.

[0003] In order to overcome the application problems caused by the poor stability of nitrile oxides, unstable nitrile oxides are generated in the reaction system in real time, and in-situ participation in the reaction is a common solution in the prior art. For example, "Synthesis of terephthalonitrile oxide and its room temperature curing performance" Fine Chemicals, 2017 (9): 1063-1069 reported the use of terephthalonitrile dichloroaldehyde oxime as a precursor, instant synthesis of terephthalonitrile oxide (structure as shown in (II)), in-situ participation in the cross-linking and curing reaction of polybutadiene, but in the system, nitrile oxides are generated while ammonium salts are produced and remain in the cured sample, affecting the performance of the cured elastomer. In addition, most nitrile oxide curing agents are difunctional nitrile oxides containing two-CNO groups, and the polymer cross-linking system to which they are applicable is limited.

[0004] Summary of the invention

[0005] In view of the deficiencies in the prior art, the object of the present invention is to provide a trifunctional nitrile oxide tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine compound which can exist stably at room temperature and contains three -CNO groups in its molecular structure and a synthesis method thereof.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine compound having the chemical structural formula shown in (I):

[0008]

[0009] The present invention also discloses a method for synthesizing the tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine compound, comprising the following steps:

[0010] Step 1: Etherification reaction

[0011] Add 2,6-dimethyl-4-hydroxybenzaldehyde and sodium hydroxide to a mixed solvent of acetone and deionized water, stir and dissolve, cool to 0-5°C, then add an acetone solution containing cyanuric chloride and heat to room temperature to react, to obtain a trifunctional aromatic formaldehyde compound;

[0012] Step 2: Oximation reaction

[0013] Add a trifunctional aromatic formaldehyde compound to tetrahydrofuran, stir and dissolve, cool to 0-5°C, then add hydroxylamine hydrochloride and sodium acetate aqueous solution and warm to room temperature for reaction, concentrate the reaction solution to collect the precipitate, and filter to obtain trifunctional aromatic formaldehyde oxime;

[0014] Step 3: Oxidative dehydrogenation

[0015] Add trifunctional aromatic formaldehyde oxime to DMF, cool to 0-5°C, then add N-bromosuccinimide and triethylamine in sequence, then warm to room temperature for reaction, pour the reaction solution into deionized water to precipitate, filter, wash with water and methanol in sequence to obtain a crude product, and purify the crude product by column chromatography to obtain a tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine compound.

[0016] Furthermore, in step 1, the molar ratio of cyanuric chloride, 2,6-dimethyl-4-hydroxybenzaldehyde and sodium hydroxide is 1:(3-6):(3-6).

[0017] Furthermore, in step 1, the molar ratio of cyanuric chloride, 2,6-dimethyl-4-hydroxybenzaldehyde and sodium hydroxide is 1:3:3.

[0018] Furthermore, in step 2, the molar ratio of trifunctional aromatic formaldehyde, hydroxylamine hydrochloride and sodium acetate is 1:(3-6):(3-6).

[0019] Furthermore, in step 2, the molar ratio of trifunctional aromatic formaldehyde, hydroxylamine hydrochloride and sodium acetate is 1:6:6.

[0020] Furthermore, in step 3, the molar ratio of trifunctional aromatic formaldehyde oxime, N-bromosuccinimide and triethylamine is 1:(3-6):(3-6).

[0021] Furthermore, in step 3, the molar ratio of trifunctional aromatic formaldehyde oxime, N-bromosuccinimide and triethylamine is 1:4.5:4.5.

[0022] Furthermore, the reaction time in step 1 and step 2 is 24 hours, and the reaction time in step 3 is 1 to 5 hours.

[0023] Furthermore, the reaction time in step 3 is 2.5 h.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) The tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine compound of the present invention can be stably present at room temperature (20-30° C.), and is easy to preserve and store for a long time. The terephthalonitrile oxide in the comparative literature cannot be stably present at room temperature;

[0026] (2) The tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine compound of the present invention contains three -CNO groups in its molecular structure, and has wider application in olefin-containing polymer crosslinking systems. The terephthalonitrile oxide in the comparative literature only contains two -CNO groups.

[0027] (3) The tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine compound of the present invention has a stable structure and can undergo a cycloaddition reaction with a compound containing an unsaturated double bond, and can be applied to the field of non-isocyanate room temperature curing molding of solid propellants. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is the hydrogen nuclear magnetic spectrum of the tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine compound of the present invention.

[0029] Figure 2 This is the infrared spectrum of the tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine compound of the present invention. DETAILED DESCRIPTION

[0030] The present invention is further described below in conjunction with embodiments, the purpose of which is to provide a better understanding of the essential features of the present invention as embodied in the contents of the present invention. Therefore, the examples given should not be regarded as limiting the scope of protection of the present invention.

[0031] The tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine compound provided by the present invention has the following structural formula:

[0032]

[0033] The synthesis route of the tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine compound of the present invention is as follows:

[0034]

[0035] The present invention introduces a methyl group at the ortho position of the aromatic nitrile oxygen group to improve the stability of the trifunctional nitrile oxide based on the steric hindrance effect;

[0036] The synthesis method of the tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine compound of the present invention comprises the following steps:

[0037] Step 1: Etherification reaction

[0038] 2,6-dimethyl-4-hydroxybenzaldehyde and sodium hydroxide are added to a mixed solvent of acetone and deionized water, stirred and dissolved, cooled to 0-5°C, then an acetone solution containing cyanuric chloride is added and the temperature is raised to room temperature for reaction for 24 hours to obtain a trifunctional aromatic formaldehyde compound; the molar ratio of the cyanuric chloride, 2,6-dimethyl-4-hydroxybenzaldehyde and sodium hydroxide is 1:3:3.

[0039] Step 2: Oximation reaction

[0040] A trifunctional aromatic formaldehyde compound is added to tetrahydrofuran, stirred and dissolved, and the temperature is lowered to 0-5°C, and then hydroxylamine hydrochloride and sodium acetate aqueous solution are added and the temperature is raised to room temperature to react for 24 hours, the reaction solution is concentrated to collect the precipitate, and the trifunctional aromatic formaldehyde oxime is obtained by suction filtration; the molar ratio of the trifunctional aromatic formaldehyde, hydroxylamine hydrochloride and sodium acetate is 1:(3-6):(3-6).

[0041] Preferably, the molar ratio of trifunctional aromatic formaldehyde, hydroxylamine hydrochloride and sodium acetate is 1:6:6.

[0042] Step 3: Oxidative dehydrogenation

[0043] Add trifunctional aromatic formaldehyde oxime to DMF, cool to 0-5°C, then add N-bromosuccinimide and triethylamine in sequence, then warm to room temperature for reaction for 1-5h, pour the reaction solution into deionized water to precipitate, filter, wash with water and methanol in sequence to obtain a crude product, and purify the crude product by column chromatography to obtain tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine compound. The molar ratio of trifunctional aromatic formaldehyde oxime, N-bromosuccinimide and triethylamine is 1:(3-6):(3-6).

[0044] Preferably, the molar ratio of trifunctional aromatic formaldehyde oxime, N-bromosuccinimide and triethylamine is 1:4.5:4.5, and the reaction time is 2.5 h.

[0045] Example 1

[0046] This embodiment provides a method for synthesizing a tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine compound, comprising the following steps:

[0047] Step 1: Etherification reaction

[0048] 2,6-dimethyl-4-hydroxybenzaldehyde (2.27 g, 15 mmol) and sodium hydroxide (0.6 g, 15 mmol), 15 mL of acetone and 15 mL of deionized water were added to a round-bottom flask, stirred and dissolved at room temperature, cooled to 0°C, and then 15 mL of acetone solution containing cyanuric chloride (0.92 g, 5 mmol) was added dropwise. After the addition was complete, the temperature was raised to room temperature and reacted for 24 hours. The reaction solution was poured into 200 mL of deionized water to precipitate, filtered, and the filter cake was washed with acetone and water in turn. It was dried to obtain 2.4 g of a white powdery trifunctional aromatic formaldehyde compound with a yield of 91.4%.

[0049] Structure identification: 1 H NMR (CDCl3, 500MHz, ppm), δ: 10.54, 6.88, 2.58. 13 CNMR (CDCl3, 125MHz, ppm), δ: 192.09, 173.29, 153.93, 143.64, 130.65, 122.30, 20.70.

[0050] Step 2: Oximation reaction

[0051] Trifunctional aromatic formaldehyde (500 mg, 0.95 mmol) and tetrahydrofuran (10 mL) were added into a round-bottom flask, stirred at room temperature to form a suspension, cooled to 0°C, and then hydroxylamine hydrochloride (198 mg, 2.85 mmol) and 2.0 mL of sodium acetate (234 mg, 2.85 mmol) aqueous solution were added in sequence. The reaction was stirred overnight. After the reaction was completed, the solvent was removed by rotary evaporation, and the precipitate was collected. After ultrasonic washing with water (25 mL × 3) and dichloromethane (10 mL × 2), the filter cake was filtered off, and vacuum dried at room temperature to obtain 410 mg of white powdery trifunctional aromatic formaldehyde oxime in a yield of 75.9%.

[0052] Step 3: Oxidative dehydrogenation

[0053] Trifunctional aromatic formaldehyde oxime (500 mg, 0.88 mmol) and DMF (20 mL) were added into a round-bottom flask, stirred and dispersed, then cooled to 0°C, NBS (705 mg, 3.96 mmol) was added in batches, stirred and reacted for 30 min, triethylamine (401 mg, 3.96 mmol) was slowly added dropwise, and after the addition was completed, the temperature was raised to room temperature, and the reaction was stirred for 1 h. After the reaction was completed, the reaction solution was poured into 200 mL of deionized water to precipitate, filtered, and the filter cake was washed with water and methanol in turn to obtain a crude product, which was purified by column chromatography (eluent: dichloromethane) to obtain 350 mg of tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine compound with a yield of 70.5%.

[0054] Example 2

[0055] The difference between this embodiment and Example 1 is that the molar ratio of trifunctional aromatic formaldehyde, hydroxylamine hydrochloride and sodium acetate in step 2 is 1:4.5:4.5. Step 3, the reaction time is 2.5 hours.

[0056] Specifically, step 2: oximation reaction

[0057] Trifunctional aromatic formaldehyde (500 mg, 0.95 mmol) and tetrahydrofuran (10 mL) were added into a round-bottom flask, stirred at room temperature to form a suspension, cooled to 0°C, and then hydroxylamine hydrochloride (297 mg, 4.28 mmol) and 2.0 mL of sodium acetate (351 mg, 4.28 mmol) aqueous solution were added in sequence. The reaction was stirred overnight. After the reaction was completed, the solvent was removed by rotary evaporation, and the precipitate was collected. After ultrasonic washing with water (25 mL × 3) and dichloromethane (10 mL × 2), the filter cake was filtered off, and vacuum dried at room temperature to obtain 480 mg of trifunctional aromatic formaldehyde oxime as a white powder with a yield of 88.9%.

[0058] Step 3: Oxidative dehydrogenation

[0059] Trifunctional aromatic formaldehyde oxime (500 mg, 0.88 mmol) and DMF (20 mL) were added into a round-bottom flask, stirred and dispersed, then cooled to 0°C, NBS (705 mg, 3.96 mmol) was added in batches, stirred and reacted for 30 min, triethylamine (401 mg, 3.96 mmol) was slowly added dropwise, and after the addition was completed, the temperature was raised to room temperature, and the reaction was stirred for 2.5 h. After the reaction was completed, the reaction solution was poured into 200 mL of deionized water to precipitate, filtered, and the filter cake was washed with water and methanol in turn to obtain a crude product, which was purified by column chromatography (eluent: dichloromethane) to obtain 410 mg of tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine compound with a yield of 82.7%.

[0060] Embodiment 3:

[0061] The difference between this embodiment and Example 1 is that the molar ratio of trifunctional aromatic formaldehyde, hydroxylamine hydrochloride and sodium acetate in step 2 is 1:6:6. Step 3, the reaction time is 5 hours.

[0062] Specifically, step 2: oximation reaction

[0063] Trifunctional aromatic formaldehyde (500 mg, 0.95 mmol) and tetrahydrofuran (10 mL) were added into a round-bottom flask, stirred at room temperature to form a suspension, cooled to 0°C, and then hydroxylamine hydrochloride (396 mg, 5.7 mmol) and 2.0 mL of sodium acetate (468 mg, 5.7 mmol) aqueous solution were added in sequence. The reaction was stirred overnight. After the reaction was completed, the solvent was removed by rotary evaporation, and the precipitate was collected. After ultrasonic washing with water (25 mL × 3) and dichloromethane (10 mL × 2), the filter cake was filtered off, and vacuum dried at room temperature to obtain 523 mg of trifunctional aromatic formaldehyde oxime as a white powder with a yield of 93.4%.

[0064] Structure identification: 1 H NMR (DMSO-d6, 500MHz, ppm), δ: 11.30, 8.31, 6.98, 2.32; 13 C NMR (DMSO-d6, 125MHz, ppm), δ: 173.49, 151.10, 147.35, 139.10, 128.70, 121.27, 21.36.

[0065] Step 3: Oxidative dehydrogenation

[0066] Trifunctional aromatic formaldehyde oxime (500 mg, 0.88 mmol) and DMF (20 mL) were added into a round-bottom flask, stirred and dispersed, then cooled to 0°C, NBS (705 mg, 3.96 mmol) was added in batches, stirred and reacted for 30 min, triethylamine (401 mg, 3.96 mmol) was slowly added dropwise, and after the addition was completed, the temperature was raised to room temperature, and the reaction was stirred for 5 h. After the reaction was completed, the reaction solution was poured into 200 mL of deionized water to precipitate, filtered, and the filter cake was washed with water and methanol in turn to obtain a crude product, which was purified by column chromatography (eluent: dichloromethane) to obtain 300 mg of tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine compound with a yield of 60.5%.

[0067] Structure identification:

[0068] 1 H NMR (CDCl3, 500MHz, ppm), δ: 6.90, 2.46.

[0069] 13 C NMR (CDCl3, 125MHz, ppm), δ: 173.30, 152.21, 143.92, 120.56, 112.76, 21.10.

[0070] IR(KBr,cm -1),ν:2951,2921,2293,1708,1565,1474,1428,1370,1344,1289,1163,1064,872,813.

[0071] ESI-MS (m / z), [C 20 H 24 N6O6Cl - ], measured value 599.1405, theoretical calculated value 599.1440.

[0072] The NMR hydrogen spectrum of the synthesized target compound is shown in Figure 1 As shown, the integral ratio of each peak group is basically consistent with the ratio of the number of hydrogen atoms in the molecular structure of tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine compound. Figure 2 As shown, the strong absorption peak is 2293cm -1 It is the stretching vibration peak of C≡N-, which confirms that the target compound contains a stable -CNO group.

[0073] The above structural identification data confirm that the substance prepared by this method is indeed tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine.

[0074] Properties of tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine

[0075] (1) Solubility: Soluble in dichloromethane, chloroform, tetrahydrofuran, etc., slightly soluble in ethyl acetate, insoluble in water, petroleum ether, etc.

[0076] (2) Room temperature stability: It is a stable white solid powder at room temperature (20-30°C) and can be stored for a long time.

[0077] Uses of tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine

[0078] The tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine compound of the present invention has a stable structure, can undergo a cycloaddition reaction with a compound containing an unsaturated double bond, and can be applied to the field of non-isocyanate room temperature curing molding of solid propellants.

[0079] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine compound, characterized in that It has the chemical structural formula shown in (I): (I)。 2. A method for synthesizing the tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine compound according to claim 1, characterized in that: The following steps are involved: Step 1: Etherification reaction Add 2,6-dimethyl-4-hydroxybenzaldehyde and sodium hydroxide to a mixed solvent of acetone and deionized water, stir and dissolve, cool to 0-5°C, then add an acetone solution containing cyanuric chloride and heat to room temperature to react, to obtain a trifunctional aromatic formaldehyde compound; Step 2: Oximation reaction Add a trifunctional aromatic formaldehyde compound to tetrahydrofuran, stir and dissolve, cool to 0-5°C, then add hydroxylamine hydrochloride and sodium acetate aqueous solution and warm to room temperature for reaction, concentrate the reaction solution to collect the precipitate, and filter to obtain a trifunctional aromatic formaldehyde oxime compound; Step 3: Oxidative dehydrogenation Add a trifunctional aromatic formaldehyde oxime compound to DMF, cool to 0-5°C, then add N-bromosuccinimide and triethylamine in sequence, then warm to room temperature for reaction, pour the reaction solution into deionized water to precipitate, filter, wash with water and methanol in sequence to obtain a crude product, and purify the crude product by column chromatography to obtain a tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine compound; The molar ratio of cyanuric chloride, 2,6-dimethyl-4-hydroxybenzaldehyde and sodium hydroxide in step 1 is 1:(3-6):(3-6); In step 2, the molar ratio of trifunctional aromatic formaldehyde, hydroxylamine hydrochloride and sodium acetate is 1:(3-6):(3-6); In step 3, the molar ratio of trifunctional aromatic formaldehyde oxime, N-bromosuccinimide and triethylamine is 1:(3~6):(3~6).

3. The method for synthesizing the tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine compound according to claim 2, characterized in that: The molar ratio of cyanuric chloride, 2,6-dimethyl-4-hydroxybenzaldehyde and sodium hydroxide in step 1 is 1:3:

3.

4. The method for synthesizing the tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine compound according to claim 2, characterized in that: In step 2, the molar ratio of trifunctional aromatic formaldehyde, hydroxylamine hydrochloride and sodium acetate is 1:6:

6.

5. The method for synthesizing the tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine compound according to claim 2, characterized in that: In step 3, the molar ratio of trifunctional aromatic formaldehyde oxime, N-bromosuccinimide and triethylamine is 1:4.5:4.

5.

6. The method for synthesizing a tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine compound according to claim 2, characterized in that: The reaction time in step 1 and step 2 is 24 h, and the reaction time in step 3 is 1-5 h.

7. The method for synthesizing a tris(3,5-dimethyl-4-nitrileoxyphenoxy)triazine compound according to claim 2, characterized in that: The reaction time in step 3 is 2.5 h.

Images