CN108586803A - A kind of spiro-phosphate fire retardant preparation method and applications containing DOPO and benzoxazine - Google Patents

Abstract

A method for preparing a spirocyclic phosphate flame retardant containing DOPO and benzoxazine, and its application. In the presence of methanol, 4-aminophenol, 2-hydroxybenzaldehyde, DOPO, and formaldehyde are boiled in a single pot to synthesize intermediate I. Phosphorus oxychloride and pentaerythritol react to synthesize intermediate II (spirocyclic phosphate diacyl chloride). Intermediate I reacts with intermediate II to obtain a white solid powder containing DOPO and benzoxazine as a spirocyclic phosphate flame retardant. The initial decomposition temperature of this flame retardant is approximately 320℃, with a weight loss of 9% at 450℃, and a char residue of 58% at 700℃. This flame retardant exhibits good thermal stability, high char residue, and good flame retardant effect, and can be used for halogen-free flame retardancy of polypropylene and ABS.

Description

A kind of preparation method of spirocyclic phosphate flame retardant containing DOPO and benzoxazine and its application

technical field

The invention belongs to the technical field of phosphorus-nitrogen synergistic flame-retardant compounds, and specifically relates to a spirocyclic phosphate flame retardant containing DOPO and benzoxazine. The flame retardant has good thermal stability, high carbon residue rate, Good flame retardant effect, can be used for non-halogen flame retardant of polypropylene and ABS.

Background technique

Halogenated flame retardants are flame retardant polymers that produce hydrogen halides and other corrosive and toxic thermal cracking products when burned. As people's awareness of environmental protection continues to increase, halogen-free flame retardants have become an inevitable trend in the development of flame retardants. DOPO is a new type of flame retardant intermediate. Its structure contains active phosphorus-hydrogen bonds. It is very active to olefins, epoxy bonds and carbonyl groups, and can react to generate many derivatives. DOPO and its derivatives contain linking The structure of benzene ring and phenanthrene ring, especially the introduction of side phosphorus group in the form of cyclic O=P-O bond, has higher thermal stability and chemical stability than non-cyclic organophosphate, better flame retardancy, and is halogen-free, Smoke-free, environmentally friendly, not easy to migrate. However, the direct use of DOPO monomer for flame retardancy of polymer materials has the disadvantage that it begins to decompose at 180°C, which cannot meet the processing temperature of most polymer materials. The spirocyclic phosphate has a higher thermal decomposition temperature, and all coke is formed at 400°C. The coke can still resist oxidation at 600°C or even higher temperature, and can also be used as a flame retardant itself. The spirocyclic phosphate flame retardant has dual functions of flame retardancy and plasticization, and is less harmful to the environment. It can effectively reduce the heat release rate of materials, reduce the release of toxic gases and smoke, and is an excellent substitute for halogen flame retardants. However, its application and development are relatively slow, few products have been put into commercial production, and there are disadvantages such as complex synthesis process, low yield and high price.

Contents of the invention

The purpose of the present invention is to overcome the weak point in the above-mentioned prior art, provide a kind of technique simple, production cost is low, overcome the shortcoming that spirocyclic phosphate price is high, synthesize intermediate II (spirophosphoric acid ester) by reaction of phosphorus oxychloride and pentaerythritol Cyclic phosphate dichloride), use 4-aminophenol, 2-hydroxybenzaldehyde, DOPO, formaldehyde to synthesize intermediate I, intermediate I and intermediate II react to form a new type of DOPO and benzoxazine with excellent flame retardancy spirocyclic phosphate flame retardants.

The object of the present invention is to realize like this: a kind of spirocyclic phosphate flame retardant containing DOPO and benzoxazine, this compound has following chemical structural formula:

The preparation method of the spirocyclic phosphate flame retardant containing DOPO and benzoxazine:

A: Dissolve 4-aminophenol, 2-hydroxybenzaldehyde, DOPO in an organic solvent, pass nitrogen gas, react at room temperature for 10-15 hours, add formaldehyde, react at room temperature for 4-10 hours, and then heat up to 60-75 After reacting at ℃ for 10-15 hours, pour the reaction solution into water, a large amount of white solid precipitates out, filter it with suction, and dry it to obtain Intermediate I. The reaction equation is as follows:

B: Add pentaerythritol, phosphorus oxychloride, and organic solvents into a flask equipped with a stirring, reflux condenser, and hydrogen chloride absorption device, stir, raise the temperature to 50°C to 90°C, react until no hydrogen chloride is released, cool and filter, dichloromethane After washing and drying, intermediate II is obtained, and the reaction equation is as follows:

C: Add an organic solvent to intermediate II, stir to dissolve it, then add intermediate I, add acid-binding agent dropwise under ice-bath cooling, after the dropwise addition, heat to 130-170°C, evaporate the solvent after the reaction is complete , filtered and recrystallized to obtain a white crystalline powder, the reaction equation is as follows:

Spirocyclic phosphate flame retardant containing DOPO and benzoxazine.

The application of spirocyclic phosphate flame retardant containing DOPO and benzoxazine as phosphorus nitrogen synergistic flame retardant additive for polypropylene and ABS.

In the described step A, the organic solvent is any one of methanol, ethanol, and acetonitrile.

More preferably, in step A, the reaction temperature after heating is 65-70°C; the solvent is methanol.

In described step A, the ratio of the amount of substance of 4-aminophenol, 2-hydroxybenzaldehyde, DOPO is 1:1.0-1.4, and the weight of organic solvent is 4-aminophenol, 2-hydroxybenzaldehyde, DOPO total 5-8 times the weight.

In the described step B, the ratio of the amount of substances of pentaerythritol and phosphorus oxychloride is 1:2.0-2.2, and the described organic solvent is acetonitrile, and its addition weight is 5-5% of the total weight of pentaerythritol and phosphorus oxychloride. 9 times.

In the step C, the ratio of intermediate II to intermediate I is 1:2.0-2.5, and the weight of the organic solvent is 6-10 times the total weight of intermediate I and intermediate II.

The organic solvent described in the step C is any one of N,N-dimethylacetamide, N,N-dimethylformamide, dimethylsulfoxide, and the acid-binding agent is triethylamine, N , Any of N-dimethylaniline.

In the step C, the acid-binding agent is triethylamine; the solvent is N,N-dimethylformamide.

The technical scheme of the present invention is the application of the prepared spirocyclic phosphate flame retardant containing DOPO and benzoxazine in the phosphorus-nitrogen synergistic flame-retardant additive of polypropylene and ABS resin.

The beneficial effects of the present invention are as follows:

(1) The flame retardant provided by the present invention is to introduce double DOPO and benzoxazine structural units into the spirocyclic phosphate compound to achieve the purpose of phosphorus and nitrogen synergistic flame retardancy, and has higher phosphorus content, nitrogen content, resistance Thermal and high-temperature char formation rate, it can be used as a reactive flame retardant, which can be inserted into polypropylene, and can also be used as an additive flame retardant to meet the high heat resistance requirements of flame retardants. Halogen-free flame retardant of ABS.

(2) The product synthesized by the present invention has good thermal stability, high flame retardancy and a purity of 98.5%.

(3) The raw materials used in the present invention are easy to get, advanced in technology, and easy to industrialized production.

Detailed ways

The present invention will be further described below in conjunction with the examples, but the protection scope of the present invention is not limited to the scope expressed in the examples.

In order to develop a flame retardant with higher flame retardant efficiency, the core structural fragments of double DOPO, benzoxazine, and spirocyclic phosphate compounds were rationally assembled and modified to synthesize a spirocyclic phosphate containing DOPO and benzoxazine Ester composite flame retardant.

Example 1:

A preparation method of a spirocyclic phosphate flame retardant containing DOPO and benzoxazine, the steps are:

Add 13.10 g (0.12 mol) of 4-aminophenol, 14.66 g (0.12 mol) of 2-hydroxybenzaldehyde, 25.94 g (0.12 mol) of DOPO, and 250 mL of methanol into a flask equipped with a stirrer, a reflux condenser and a tail gas absorber. Nitrogen gas was introduced, and after 10 hours of reaction at room temperature, 9.84 g (0.12 mol) of 37% formaldehyde was added, and the reaction was carried out at room temperature for 6 hours. After the reaction, the reaction solution was poured into 300 mL of water, and a large amount of white solid was precipitated, which was filtered by suction and dried in vacuum to obtain Intermediate I with a yield of 91.2%.

Add 27.24g (0.20mol) of pentaerythritol, 300mL of acetonitrile and 91.2g (0.60mol) of phosphorus oxychloride (POCl ₃ ) into a flask equipped with a stirrer, reflux condenser and tail gas absorption device, 75°C-80°C React for 12 hours until no hydrogen chloride gas is generated; cool to room temperature, filter with suction, wash with dichloromethane and ethanol, and dry in vacuo to obtain Intermediate II, a white solid powder, with a yield of 72.6%.

In a flask containing 200 mL of N,N-dimethylformamide, add 14.85 g (0.05 mol) of intermediate II, stir to dissolve it, and add 44.11 g (0.10 mol) of intermediate I in batches. Under cooling, add 12.15g (0.12mol) triethylamine dropwise, stir, and after the dropwise addition is completed, gradually heat to 145-150°C. After the reaction is completed, distill N,N-dimethylformamide, pour it into 150mL water, and use Recrystallization from acetonitrile-water mixed solvent gave the target compound as a white solid powder with a yield of 86.2%.

The chemical reaction formula that the present invention prepares compound is:

Spirocyclic phosphate flame retardant containing DOPO and benzoxazine.

The spirocyclic phosphate flame retardant containing DOPO and benzoxazine prepared by the present invention has a white solid powder appearance. The initial decomposition temperature of the compound is about 320°C, and the weight loss reaches 9% at 450°C. The carbon residue rate of the flame retardant reaches 58%. The flame retardant has good thermal stability and high carbon residue rate. The higher the carbon residue rate at high temperature, the better the flame retardant effect, so the flame retardant has better flame retardant effect.

The analysis result of the spirocyclic phosphate flame retardant containing DOPO and benzoxazine that the present invention makes is as follows:

The appearance of the compound is a white solid. The results of infrared spectrum analysis: FT-IR (KBr), v/cm ^-1 : around 3009 is the CH stretching vibration peak of the benzene ring, around 1564 is the P-Ph stretching vibration peak, around 1163, 921 is the PO-Ph stretching vibration peak, P=O stretching vibration peak near 1232; 1600cm ^-1 , 1581cm ^-1 , 1463cm ^-1 absorption peak of benzene ring, 842cm ^-1 skeleton vibration peak of pentaerythritol in the helical ring structure; nuclear magnetic resonance Proton spectrum analysis results: ¹ H NMR(DMSO-d ₆ ,400MHz):7.65-7.52(m,5H,Ar-H),7.41-7.32(m,6H,Ar-H),7.15-7.02(m,8H ,Ar-H),6.93-6.82(m,7H,Ar-H),6.72-6.53(m,6H,Ar-H),5.11(s,2H,PCHN),5.03(s,4H,NCH ₂ O ), 4.23 (d, J=7.5, 8H, OCH ₂ ).

Example 2:

The solvent was changed to N, N-dimethylacetamide, and the others were the same as Example 1, and the yield of the target compound was 80.5%.

The solvent was changed to dimethyl sulfoxide, and the others were the same as Example 1, and the yield of the target compound was 81.7%.

Example 3:

The acid-binding agent triethylamine was replaced by N,N-dimethylaniline, and the others were the same as Example 1, and the yield of the target compound was 83.6%.

Example 4:

Increase the amount of intermediate I to 46.31 g (0.105 mol), and the others are the same as Example 1, and the yield of the target compound is 88.3%.

Example 5:

Increase the amount of intermediate I to 48.51 g (0.11 mol), and the others are the same as Example 1, and the yield of the target compound is 91.4%.

Embodiment 6:

Increase the amount of intermediate I to 50.72 g (0.115 mol), and the others are the same as Example 1, and the yield of the target compound is 89.3%.

Embodiment 7:

Increase the amount of intermediate I to 52.82g (0.12mol), and the others are the same as Example 1, and the yield of the target compound is 83.1%.

Embodiment 8:

Increase the amount of intermediate I to 55.13 g (0.125 mol), and the others are the same as Example 1, and the yield of the target compound is 81.3%.

The spirocyclic phosphate flame retardant containing DOPO and benzoxazine provided by the present invention is used as a phosphorus-nitrogen synergistic flame-retardant additive for polypropylene and ABS as follows:

According to the test standard for the combustion performance of insulating laminates, the sample strips were made, and the limiting oxygen index (LOI) test was carried out with the JF-3 oxygen index tester, and the UL94 vertical combustion performance test was carried out with the FZ-5401 vertical combustion instrument. The measurement results are shown in the following table 1-2 shown.

Table 1 The effect of flame retardant flame retardant polypropylene of embodiment 1 of the present invention

Table 2 The effect of flame retardant ABS of embodiment 1 of the present invention

Claims (10)

1. A spirocyclic phosphate flame retardant containing DOPO and benzoxazine is characterized in that its chemical structural formula is as follows: The flame retardant contains DOPO and the spirocyclic phosphate structure of benzoxazine. 2. prepare the synthetic method of the spirocyclic phosphate flame retardant containing DOPO and benzoxazine described in claim 1, it is characterized in that, comprises the following steps: A: Dissolve 4-aminophenol, 2-hydroxybenzaldehyde, DOPO in an organic solvent, react at room temperature for 10-15 hours, add formaldehyde, react at room temperature for 4-10 hours, then heat up to 60-75°C for 10- After 15 hours, the reaction solution was poured into water, and a large amount of white solid was precipitated, which was filtered by suction and dried to obtain Intermediate I. The reaction equation is as follows: B: Add pentaerythritol, phosphorus oxychloride, and organic solvents into a flask equipped with a stirring, reflux condenser, and hydrogen chloride absorption device, stir, raise the temperature to 50°C to 90°C, react until no hydrogen chloride is released, cool and filter, dichloromethane After washing and drying, intermediate II is obtained, and the reaction equation is as follows: C: Add an organic solvent to intermediate II, stir to dissolve it, then add intermediate I, add acid-binding agent dropwise under ice-bath cooling, after the dropwise addition, heat to 130-170°C, evaporate the solvent after the reaction is complete , filtered and recrystallized to obtain a white crystalline powder, the reaction equation is as follows: Spirocyclic phosphate flame retardant containing DOPO and benzoxazine. 3. The preparation method of the spirocyclic phosphate flame retardant containing DOPO and benzoxazine according to claim 2, characterized in that: in step A, the organic solvent is any one of methanol, ethanol, and acetonitrile. 4. The preparation method of the spirocyclic phosphate flame retardant containing DOPO and benzoxazine according to claim 3, characterized in that: in step A, the reaction temperature after heating up is 65-70°C; the solvent to methanol. 5. the preparation method of the spirocyclic phosphate flame retardant containing DOPO and benzoxazine according to claim 2, is characterized in that: in step A, the substance of 4-aminophenol, 2-hydroxybenzaldehyde, DOPO The ratio of the amount is 1:1.0-1.4, and the weight of the organic solvent is 5-8 times of the total weight of 4-aminophenol, 2-hydroxybenzaldehyde and DOPO. 6. the preparation method of the spirocyclic phosphate flame retardant containing DOPO and benzoxazine according to claim 2 is characterized in that: in step B, the ratio of the amount of substances of pentaerythritol and phosphorus oxychloride is 1 : 2.0-2.2, described organic solvent is acetonitrile, and its added weight is 5-9 times of the total weight of pentaerythritol and phosphorus oxychloride. 7. the preparation method of the spirocyclic phosphate flame retardant containing DOPO and benzoxazine according to claim 2 is characterized in that: in step C, the ratio of the amount of substance of intermediate II and intermediate I is 1: 2.0-2.5, the weight of the organic solvent is 6-10 times the total weight of intermediate I and intermediate II. 8. the preparation method of the spirocyclic phosphate flame retardant containing DOPO and benzoxazine according to claim 2 is characterized in that: the organic solvent described in the step C is N, N-dimethylacetamide, Any one of N,N-dimethylformamide and dimethyl sulfoxide, and the acid-binding agent is any one of triethylamine and N,N-dimethylaniline. 9. the preparation method of the spirocyclic phosphate flame retardant containing DOPO and benzoxazine according to claim 8, is characterized in that: in step C, described acid-binding agent is triethylamine; Described The solvent is N,N-dimethylformamide. 10. The application of the spirocyclic phosphate flame retardant containing DOPO and benzoxazine prepared according to any one of claims 2-9 in the phosphorus-nitrogen synergistic flame-retardant additive of polypropylene and ABS resin.