Full-bio-based aryl diamine flame retardant and full-bio-based aryl diamine polyimide thin film

Abstract

Disclosed in the present invention are a full-bio-based aryl diamine flame retardant and a full-bio-based aryl diamine polyimide thin film. The structures thereof are respectively as shown in formula

Description

5 The present invention belongs to the field of bio-based polymer materials, and particularly relates to a fiill-bio-based aryl diamine flame retardant and a preparation method and application thereof, and a fiill-bio-based aryl diamine polyimide film and a preparation method and application thereof. 10 BACKGROUND Lignocellulose biomass is considered as a renewable alternative carbon source, which is mainly composed of cellulose, hemicellulose and lignin. Lignin is an irregular aromatic biopolymer, which accounts for 15% to 30% of the lignocellulose biomass, and is a component of a cell wall of a terrestrial plant. The lignin has an aromatic structure, so as to be considered as a renewable carbon 15 source derived from considerable aromatic compounds. However, the utilization of the lignin has always been limited to energy recovery, the degradation of lignin in most bio-refining processes comprises unstable ether bond breakage and C-C bond formation by a reaction intermediate through bond-breaking condensation, and the degraded lignin synthesized is usually difficult to be depolymerized, thus being usually incinerated to generate heat and electricity. In recent years, 20 researchers have been trying to find a suitable renewable raw material to produce a polymer. In particular, the development of lignin monomer bio-based polymer has been greatly concerned. Among lignin treatment methods, it is a noteworthy method to process the lignin into aromatic aldehyde, vanillin and syringaldehyde through oxidative depolymerization catalyzed by alkali. These substances are widely used in pharmaceutical, food and perfume industries. The vanillin is used to 25 produce papaverine, flutivazide and levodopa, the syringaldehyde may be used to synthesize drugs such as trimethoxybenzaldehyde and trimethoprim, and the p-hydroxybenzaldehyde is used in polymer synthesis and other branches of chemical industry. A method of producing the vanillin by oxidizing lignosulfonate accounts for 80% of the vanillin production market. It is of great significance to develop and prepare a full-bio-based functional material by structural modification of lignin 30 oxidative degradation products comprising the vanillin and other compounds and sugar platform biological fermentation products. Phosphate containing nitrogen has a good intumescent flame-retardant effect, wherein the nitrogen in this kind of flame retardants mainly comes from amine compounds such as amine, diamine and melamine. The nitrogen is amain component of an intumescent flame retardant, a flame-retardant 35 mechanism of a phosphorus-nitrogen intumescent flame retardant is that the flame retardant releases incombustible gases and phosphoric acid during pyrolysis, these incombustible gases may dilute oxygen in air, and the phosphoric acid is used as a catalyst to promote coking and charring. During 10 09 24 combustion, a protective film of a porous coking carbon layer can be formed on a surface, and the porous coking carbon layer can insulate heat, prevent oxygen, suppress fume and enhance a selfextinguishing performance of combustion polymer. However, most intumescent flame retardants containing a phosphorus-nitrogen structure are low-molecular compounds, which have poor thermal 5 stability and compatibility with a polymer substrate. According to recent reports, the thermal stability and carbon residue rate of the polymeric phosphorus-nitrogen intumescent flame retardant are both obviously improved, thus showing extraordinary flame-retardant effect. The phosphorus-nitrogen intumescent flame retardants are widely concerned as a kind of environmentally friendly and efficient flame retardants. However, traditional phosphorus-nitrogen 10 intumescent flame retardants have low flame retardant efficiency, low thermal stability and weak water resistance. Therefore, some researchers are devoted to exploring a P-N compound with high thermal stability and flame retardant efficiency to meet the needs of some special applications. Although the P-N compound has these advantages, the P-N compounds in many current reports are mostly small molecules or oligomers, leading to poor water resistance or easy precipitation from the 15 substrate. Most polymers often show an enhanced mechanical performance as long as they have sufficient molecular weight, and polymers containing a phosphoramide structure have good thermal stability and low flammability. Polyphosphamide polymer flame retardants are a kind of environmentally friendly and efficient flame retardants with excellent thermal stability, good carbon residue performance and good compatibility with a matrix, thus having a good development 20 prospect. However, at this stage, these compounds are either expensive or complicated in manufacturing and processing technology, and their applications are quite limited. There are a few of researches on these flame retardants, but they represent a development direction of flameretardant polymer materials. Therefore, the present invention provides a fiill-bio-based aryl diamine flame retardant and a 25 preparation method and application thereof, and a fiill-bio-based aryl diamine polyimide film and a preparation method and application thereof. SUMMARY Object of invention: the technical problem to be solved by the present invention is to provide a 30 fiill-bio-based aryl diamine flame retardant and a preparation method and application thereof aiming at the defects in the prior art. The technical problem to be further solved by the present invention is to provide a fiill-bio-based aryl diamine polyimide and a preparation method and application thereof. Idea of invention: in one aspect, according to the present invention, the structural design is 35 carried out by using a lignin oxidative degradation product and a sugar platform-fermented ketone compound as initial raw materials, and a fiill-bio-based aryl diamine flame retardant is synthesized, thus avoiding the dependence on fossil resources caused by the production of a traditional 10 09 24 polyurethane flame retardant. A large number of aromatic rings are introduced into the flame retardant, the aromatic ring structures have strong rigidity and large steric hindrance, the increase of the aromatic ring structures improves the thermal stability of a flame-retardant material. Moreover, incombustible gases may be generated when a polymer with a main chain containing nitrogen and 5 phosphorus is combusted, these incombustible gases may form a phosphorus-carbon foam insulation layer with a pyrophosphoric acid protective film on a surface of the polymer, and the insulation layer may prevent the material from being further combusted at a high temperature. In another aspect, according to the present invention, the structural design is carried out by using a lignin oxidative degradation product and a sugar platform-fermented ketone compound as initial 10 raw material, and a full-bio-based aryl diamine polyimide is synthesized, thus avoiding the dependence on fossil resources caused by the production of a traditional polyimide. A double bond structure is introduced into the polyimide, the double bond structure may provide a flexible chain segment, which is conductive to improving the flexibility and processability of the polyimide material, and the double bond structure reduces hydrogen bonds between molecules, thus reducing 15 the water absorption of the material; an aromatic ring structure is introduced, and the aromatic ring structure has strong rigidity and large steric hindrance, thus improving the thermal stability of the material; and a ketone structure is introduced, which is a photosensitive group, and the photosensitive group can realize response and control to light in the polyimide, so as to expand the application fields of these materials, comprising optics, electronics, sensing, micro-nano 20 manufacturing, and the like. In order to solve the first technical problem above, the present invention discloses a compound as shown in formula I: a full-bio-based aryl diamine flame retardant, wherein, 25 Ri and Rs are independently selected from -H or -OCHs respectively; R2 is selected from -H, -CHs, -CH2CH3, -CH2-CH2- or -CH2-CH2-CH2-; in some embodiments, R2 is selected from -H, -CHs, -CH2-CH2- or -CH2-CH2-CH2-; in some embodiments, R2 is selected from -H, -CHs or -CH2-CH2-; and n is selected from 2 to 30. 30 In some embodiments, the compound as shown in formula I is any one as shown in formula 11 to formula 112, wherein n is selected from 2 to 30; in some embodiments, the compound as shown in formula I is any one as shown in formulas 11,13,16,17,18,110 and 111; and in some embodiments, the compound as shown in formula I is one as shown in formula 18 or II 1; 10 09 24 112. In order to solve the second technical problem above, the present invention discloses a 10 preparation method of the compound as shown in formula I, which comprises the following steps of: SI: subjecting a lignin oxidative depolymerization monomer compound as shown in formula III and a sugar platform bio-based ketone compound as shown in formula IV to an aldol condensation reaction to obtain a coupled bisphenol compound as shown in formula V; S2: subjecting the coupled bisphenol compound as shown in formula V to a phenolic hydroxyl 15 amination reaction without metal or metal catalysis to obtain an aryl diamine compound as shown in formula VI; S3: subjecting the aryl diamine compound as shown in formula VI to a substitution reaction with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to obtain a compound as shown in formula VII; and 20 S4: subjecting the compound as shown in formula VII to a solution polycondensation reaction with phenyl dichlorophosphate to obtain the compound as shown in formula I; 10 09 24 wherein, Ri and Rs are independently selected from -H or -OCHs respectively; R2 is selected from -H, -CHs, -CH2CH3, -CH2-CH2- or -CH2-CH2-CH2-; in some embodiments, 5 R2 is selected from -H, -CHs, -CH2-CH2- or -CH2-CH2-CH2-; in some embodiments, R2 is selected from -H, -CHs or -CH2-CH2-. In the step SI, the lignin oxidative depolymerization monomer compound as shown in formula III is any one or a combination of several of vanillin, syringaldehyde and p-hydroxybenzaldehyde. In the step SI, the bio-based ketone compound as shown in formula IV is any one or a 10 combination of several of acetone, 3-pentanone, cyclopentanone and cyclohexanone. In the step SI, a solvent of the aldol condensation reaction is an alcohol compound, in some embodiments, the solvent is C1-C6 alcohol, and in some embodiments, the solvent is ethanol and / or methanol. In the step SI, a catalyst of the aldol condensation reaction is an acid catalyst, in some 15 embodiments, the catalyst is any one or a combination of several of inorganic acid, organic acid, solid acid and acidic ionic liquid, and in some embodiments, the catalyst is any one or a combination of several of hydrochloric acid, trifluoromethanesulfonic acid, sulfuric acid, phosphoric acid, and the like, and the organic acid comprises: p-toluenesulfonic acid, perfluorosulfonic acid resin, and the like, and an acidic ionic liquid +[NH3CH2CH2OH] [CH3COO], and the like. 20 In the step SI, a molar volume ratio of the lignin oxidative depolymerization monomer compound as shown in formula III and the bio-based ketone compound as shown in formula IV to the solvent in the aldol condensation reaction is 1 mmol: 0.25 mmol to 0.5 mmol: 2 mL to 5 mL; in some embodiments, a molar ratio of the lignin oxidative depolymerization monomer compound as shown in formula III to the bio-based ketone compound as shown in formula IV is 2: 1; and in some 25 embodiments, a concentration of the lignin oxidative depolymerization monomer compound as shown in formula III is 0.4 mmol / mL. In the step SI, a molar ratio of the acid catalyst to the lignin oxidative depolymerization monomer compound is 1: 15 to 25; and in some embodiments, the molar ratio is 1: 20. In the step SI, a temperature of the aldol condensation reaction ranges from room temperature to 90°C. In the step S2, the phenolic hydroxyl amination reaction is that the coupled bisphenol compound as shown in formula V is subjected to a Smiles rearrangement amination reaction without metal 5 catalysis to obtain the aryl diamine compound as shown in formula VI; and in some embodiments, the coupled bisphenol compound as shown in formula V is subjected to an amination reaction with chloroacetamide to obtain a chloroacetamide product as shown in formula X, and then the product is subjected to a Smiles rearrangement reaction to obtain the aryl diamine compound as shown in formula VI. 10 09 24 In some embodiments, catalysts of the amination reaction are potassium carbonate and potassium iodide. 15 In some embodiments, a solvent of the amination reaction is any one or a combination of several of acetone, butanone and cyclohexanone, and in some embodiments, the solvent is the butanone. In some embodiments, a molar volume ratio of the coupled bisphenol compound as shown in formula V, the chloroacetamide, the potassium carbonate and the potassium iodide to the solvent in the amination reaction is 1 mmol: 2 mmol to 3 mmol: 2 mmol to 3 mmol: 0.1 mmol to 0.3 mmol: 4 20 mL to 10 mL; in some embodiments, a molar volume ratio of the coupled bisphenol compound as shown in formula V to the chloroacetamide is 1: 2.5; in some embodiments, a molar volume ratio of the coupled bisphenol compound as shown in formula V to the potassium carbonate and the potassium iodide is 1: 2.5: 0.1; and in some embodiments, a concentration of the coupled bisphenol compound as shown in formula V is 0.1 mmol / mL. 25 In some embodiments, a temperature of the amination reaction is 50°C to 90°C; and in some embodiments, the temperature of the amination reaction is 60°C. In some embodiments, a catalyst of the Smiles rearrangement reaction is an alkali catalyst, in some embodiments, the catalyst is any one or a combination of several of potassium hydroxide, cesium hydroxide and sodium hydride, and in some embodiments, the catalyst is the potassium 30 hydroxide. In some embodiments, a solvent of the Smiles rearrangement reaction is dimethyl sulfoxide and / or N,N-dimethyl propenyl urea; and in some embodiments, a volume ratio of the dimethyl sulfoxide to the N,N-dimethyl propenyl urea is 3: 1. In some embodiments, a molar volume ratio of the chloroacetamide product and the alkali 35 catalyst to the solvent in the Smiles rearrangement reaction is 1 mmol: 2 mmol to 4 mmol: 15 mL to 10 09 24 25 mL; in some embodiments, a molar ratio of the chloroacetamide product to the alkali catalyst is 1: 4; and in some embodiments, a concentration of the chloroacetamide product is 0.1 mmol / mL. In some embodiments, a temperature of the Smiles rearrangement reaction is 90°C to 200°C, in some embodiments, the temperature is 140°C to 200°C, and in some embodiments, the temperature 5 is 150°C. In the step S3, the substitution reaction is carried out under nitrogen. In some embodiments, a molar ratio of the aryl diamine compound as shown in formula VI to the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide in the substitution reaction is 1: 4 to 6, and in some embodiments, the molar ratio of the aryl diamine compound as shown in formula VI to 10 the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide in the substitution reaction is 1: 4. In some embodiments, a temperature of the substitution reaction is 180°C to 200°C, and in some embodiments, the temperature is 180°C. In some embodiments, the substitution reaction lasts for 24 hours to 48 hours. In the step S4, the solution polycondensation reaction is that the compound as shown in formula 15 VII is subjected to a polymerization reaction with the phenyl dichlorophosphate. In some embodiments, N2 should be introduced as protective gas in the solution polycondensation reaction to prevent diamine from being oxidized. In some embodiments, a solvent of the solution polycondensation reaction is N,N-dimethylformamide. 20 In some embodiments, a molar volume ratio of the compound as shown in formula VII, the phenyl dichlorophosphate and the catalyst to the solvent is 1 mmol: 1 mmol to 1.5 mmol: 2 mmol: 5 mL to 10 mL. In some embodiments, the solution polymerization reaction is carried out under ice bath first and then carried out after heating to 20°C to 30°C, and in some embodiments, the solution polymerization 25 reaction is carried out under ice bath for 1 hour to 4 hours first and then carried out after heating to 20°C to 30°C for 5 hours to 7 hours. In order to solve the third technical problem above, the present invention discloses an application of the compound above as a flame retardant. In some embodiments, the application is an application in preparing flame-retardant 30 polyurethane rigid foam; in some embodiments, a dosage of the compound above is 1% to 20% of a total mass of isocyanate and premixed polyether polyol, in some embodiments, the dosage is 5% to 15% of the total mass, and in some embodiments, the dosage is 10% of the total mass; and in some embodiments, a limiting oxygen index of the flame-retardant polyurethane rigid foam is 23% to 40%. In some embodiments, the application is an application in preparing flame-retardant phenolic 35 foam; in some embodiments, a dosage of the compound above is 0.1% to 20% of a total mass of phenolic resin, a surfactant, a foaming agent and a curing agent, in some embodiments, the dosage is 0.3% to 25% of the total mass, in some embodiments, the dosage is 1% to 20% of the total mass, in 10 09 24 some embodiments, the dosage is 5% to 15% of the total mass, and in some embodiments, the dosage is 8% of the total mass; and in some embodiments, a limiting oxygen index of the flame-retardant phenolic foam is 50% to 64%. Beneficial effects: compared with the prior art, the present invention has the following 5 advantages. 1. According to the present invention, a lignin oxidative degradation product and an inositol platform-fermented product: a ketone compound are used as raw materials for structural design, and the full-bio-based aryl diamine flame retardant is synthesized, which may be used for replacing a traditional diamine flame retardant to prepare the flame-retardant polyurethane rigid foam and the 10 flame-retardant phenolic foam, thus improving the thermal stability and flame retardancy of the polyurethane foam material and the phenolic foam material, and avoiding the dependence on fossil resources caused by the production of the traditional flame retardant. 2. According to the present invention, the full-bio-based aryl diamine flame retardant is prepared through aldol condensation and amination paths, and double aldol condensation products 15 are constructed, so that a yield of aldol condensation catalyzed by an organic base is high; and reaction paths without metal catalysis and with metal catalysis are respectively constructed through the amination reaction, so that the reaction selectivity is high, and a yield of the final product is also higher. 3. According to the present invention, specific aryl is introduced into a molecular structure of 20 the full-bio-based aryl diamine flame retardant, which improves the thermal stability of the flame retardant. The polymer has the main chain containing a phosphorus-nitrogen bond and a molecule with a nitrogen-phosphorus synergistic effect, forms a synergistic system itself at a high temperature, and can effectively promote dehydration and carbonization during combustion, the formation of a carbon layer not only is conducive to improving a carbon residue rate and prevents 25 the combustible gases generated during thermal decomposition of the system from diffusing, but also prevents the polymer from making contact with oxygen and a heat source, thus playing a flame-retardant role. 4. According to the present invention, a lignin oxidative degradation product and an inositol platform-fermented product: a ketone compound are used as raw materials for structural design, and 30 the full-bio-based aryl diamine polyimide is synthesized, which may be used for replacing a traditional diamine to prepare the polyimide film, thus avoiding the dependence on fossil resources caused by the production of the traditional diamine compound. 5. According to the present invention, special double bond is introduced into the molecular structure of the full-bio-based aryl diamine polyimide, so that the flexibility and processability of the 35 polyimide are significantly improved. Meanwhile, a ketone group structure is introduced into the main chain of the polymer, and the addition of this photosensitive group enables the polyimide to realize response and control to light. This innovation expands the application fields of these materials, 10 09 24 comprising but being not limited to optics, electronics, sensing, micro-nano manufacturing, and the like. Therefore, this invention has the potential to promote the development of material science and engineering in many fields. 5 BRIEF DESCRIPTION OF THE DRAWINGS The present invention is further described in detail hereinafter with reference to the drawings and specific embodiments, and the advantages of the above and / or other aspects of the present invention will be clearer. FIG. 1 shows a synthetic route of a full-bio-based aryl diamine flame retardant of the present 10 invention (taking vanillin and cyclohexanone as examples, in Embodiment 7). FIG. 2 shows a hydrogen nuclear magnetic resonance spectrum of2,6-bis[(4-hydroxyl-3-methoxyphenyl)methyl]cyclohex-1-one (Vil). FIG. 3 shows a carbon spectrum of the 2,6-bis[(4-hydroxyl-3- methoxyphenyl)methyl]cyclohex-1-one (Vil). 15 FIG. 4 shows a hydrogen spectrum of a chloroacetamide substitute (XI1). FIG. 5 shows a carbon spectrum of the chloroacetamide substitute (XI1). FIG. 6 shows a mass spectrum of the chloroacetamide substitute (XI1). FIG. 7 shows a hydrogen spectrum of 2,6-bis[(4-hydroxyl-3- methoxyphenyl)methyl]cyclohexyl-l-one (VII1). 20 FIG. 8 shows a mass spectrum of the 2,6-bis[(4-hydroxyl-3-methoxyphenyl)methyl]cyclohexyl-l-one (VII1). FIG. 9 shows a synthetic route of a full-bio-based aryl diamine polyimide when Ar is selected from Ari. FIG. 10 shows a synthetic route of a full-bio-based aryl diamine polyimide in Embodiment 37. 25 FIG. 11 shows an FTIR spectrum of BTDA, bio-based diamine and a polyamic acid solution in Embodiment 37. FIG. 12 shows an FTIR spectrum of the polyamic acid solution and a polyimide film in Embodiment 37. 30 DETAILED DESCRIPTION The experimental methods described in the following embodiments are all conventional methods unless otherwise specified. The reagents and materials can all be obtained from commercial sources unless otherwise specified. Embodiments 1 to 5: preparation of Vil: 2,6-bis[(4-hydroxyl-3- 35 methoxyphenyl)methyl]cyclohex-1 -one, with reaction route as shown in FIG. 1 Aldol condensation reaction: vanillin fill 1 (20 mmol, 3.02 g) and cyclohexanone IV11 (10 mmol, 0.98 g) were added into a reaction bottle, a solvent was 50 mb of ethanol, and a catalyst was 2 mmol of hydrochloric acid, trifluoromethanesulfonic acid, perfluorosulfonic acid resin, sulfuric acid and phosphoric acid respectively. The reaction lasted for 6 hours at 70°C, a reaction solution was detected by HPLC, and conversion rates and yields were shown in the following Table 1. After the reaction, the solution was added with water for suction filtration, washed to be neutral, and then 5 subjected to suction filtration with a small amount of cold ethanol to obtain the compound VI1. ’H NMR (400 MHz, DMSO-76) 5 9.54 (s, 1H), 7.57 (d, J= 2.1 Hz, 1H), 7.12 (d, J= 2.0 Hz, 1H), 7.04 (dd, 7= 8.3, 2.0 Hz, 1H), 6.86 (d, 7= 8.2 Hz, 1H), 3.82 (s, 3H), 2.94 - 2.86 (m, 2H), 1.73 (p,7=6.1 Hz, 1H); 13CNMR(101 MHz, DMSO-d6) 5 188.97, 148.29, 147.90, 136.62, 133.96, 127.38, 124.69, 116.01, 115.27, 56.11,28.43, 23.04. MSI-MS: 367.1 [M+Na]+. The VI1 had a hydrogen 10 nuclear magnetic resonance spectrum as shown in FIG. 2 and a carbon nuclear magnetic resonance spectrum as shown in FIG. 3. 10 09 24 Table 1 Catalytic reaction efficiencies of different catalysts in Embodiments 1 to 5 Embodiment Catalyst Conversion rate Yield 1 Hydrochloric acid 91% 79.2% 2 Trifluoromethanesulfonic acid 100% 96.2% 3 Perfluorosulfonic acid resin 100% 97.3% 4 Sulfuric acid 80.6% 73.8% 5 Phosphoric acid 70.3% 56.4% Embodiment 6: preparation of chloroacetamide product XI1 Process of phenolic hydroxyl amination reaction without metal catalysis: Vil (10 mmol, 2.66 15 g), chloroacetamide (20 mmol, 1.87 g), anhydrous potassium carbonate (25 mmol, 3.45 g) and potassium iodide (1 mmol, 0.27 g) were added into a 1 L round-bottom flask, added with 70 mL of acetone, and stirred at 60°C for 6 hours. After the reaction, the solution was filtered, the filtrate was spin-dried, extracted with water and ethyl acetate, dried with anhydrous magnesium sulfate and subjected to organic phase concentration, and filtered, and the filter cake was freeze-dried to obtain 20 the chloroacetamide product, with a yield of 98.2%. 'H NMR (400 MHz, DMSO-d6) 5 7.60 (s, 1H), 7.39 (d, J = 20.0 Hz, 2H), 7.18 (d, J = 2.0 Hz, 1H), 7.12 (dd, J = 8.4, 2.0 Hz, 1H), 6.97 (d, J = 8.4 Hz, lH),4.50(s, 2H), 3.84 (s, 3H), 2.91 (d, J = 6.4 Hz, 2H), 1.73 (p, J = 6.1 Hz, 1H);13C NMR (101 MHz, DMSO-d6) 5 189.14, 170.22, 149.24, 148.49, 136.19, 135.20, 129.61, 123.97, 114.97, 114.09, 68.08, 56.14, 28.34, 22.96. MSI-MS: 481.2 [M+Na]+. The chloroacetamide substitute had a 25 hydrogen nuclear magnetic resonance spectrum as shown in FIG. 4, a carbon nuclear magnetic resonance spectrum as shown in FIG. 5, and amass spectrum as shown in FIG. 6. Embodiment 7: preparation of compound VI11 Process of Smiles rearrangement reaction: a chloroacetamide product (10 mmol, 4.80 g) and potassium hydroxide (40 mmol, 2.24 g) were accurately added into a microwave reaction bottle, 30 added with 150 mL of dimethyl sulfoxide (DMSO) and 50 mL of N,N-dimethyl propenyl urea (DMPU), and subjected to microwave heating at 150°C for 3 hours. After the reaction, the solution 10 09 24 was extracted with water and ethyl acetate, dried with anhydrous magnesium sulfate and subjected to organic phase concentration, and separated and purified by column chromatography (ethyl acetate / n-hexane) to obtain the compound VII1, with a yield of 80.3%. 'H NMR (400 MHz, DMSO-d6) 5 7.53 (s, 1H), 7.00 (d, J = 2.1 Hz, 1H), 6.98 (d, J = 1.8 Hz, 1H), 6.68 (d, J = 7.9 Hz, 5 1H), 5.34 (s, 2H), 3.82 (s, 3H), 2.92 - 2.85 (m, 2H), 1.77 - 1.70 (m, 1H);13C NMR (101 MHz, DMSO-d6) 8 190.12, 145.54, 140.10, 137.19, 131.29, 125.57, 123.49, 113.44, 112.26,55.77 (d, J = 2.6 Hz), 23.77, 23.06. MSI-MS: 365.2 [M+H]+. The VI I1 had a hydrogen nuclear magnetic resonance spectrum as shown in FIG. 7 and a mass spectrum as shown in FIG. 8. Embodiment 8: preparation of VIII1: poly[4-{[l,3-(4-amino-3-methoxyphenyl)methylene]-10 2,2-bis(9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide)cyclohexylidene]methyl} -2- methoxyaniline-phenyl dichlorohypophosphite] Introduction of aryl in carbonyl position through addition reaction: 51.88 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (0.24 mol) and 14.6 g of VII1 (0.04mol) were added into a round-bottomed flask, subjected to nitrogen replacement, and heated to 180°C to react for 4 hours, 15 and solid powder gradually became a liquid during heating. After the reaction, the solution was cooled to 110°C and dropwise added with 150 mL of toluene slowly for product precipitation to obtain a suspension, and the suspension was subjected to suction filtration to obtain a crude product, and then washed with 200 mL of tetrahydrofuran and methanol respectively to obtain 19.55 g of yellowish solid powder VIII1, with a yield of 78%. 'H NMR (400 MHz, DMSO-d6) 5 8.02 (d, 1H), 20 7.75 (d, 1H), 7.50 (m, 1H), 7.47 (m, 1H), 7.43 (m, 1H), 7.41(m, 1H), 7.36(m, 1H), 7.29(m, 1H), 6.75(d, 1H), 6.69(s, 1H), 6.05(s,lH), 4.95(s, 2H), 3.86(s, 3H), 2.09(m, 2H), 1.47(m, 1H). 13CNMR (100 MHz, DMSO-d6) 5 150.1, 147.3, 136.6, 136.5, 136.4, 132.8, 129.0, 127.7, 126.2, 125.1, 124.4, 122.1, 121.9, 121.8, 121.2, 119.9, 117.2, 111.3, 55.8, 31.8, 26.8. MSI-MS: 779.3 [M+H]+. Synthesis of bio-based flame retardant by solution polycondensation: DMF was used as a 25 solvent, and 2.1 g of phenyl dichlorophosphate (10 mmol) and 7.41 g of VIII1 (10.5 mmol) were added into a round-bottomed flask to react in ice bath for 3 hours, and then heated to 25°C to react for 6 hours to obtain Ill, with a yield of 75%. Embodiment 9: preparation of HO: poly[4-{[2,2-bis(9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide)-3-[(4-aminophenyl)methylene]cyclohexylidene]methyl} aniline-30 phenyl dichlorohypophosphite] With reference to the method in Embodiment 1, V10 was prepared by replacing vanillin with p-hydroxybenzaldehyde, with a yield of 96.8%. 'H NMR (400 MHz, DMSO-d6) 5 9.68 (s, 1H), 7.74 (d, J = 8.7 Hz, 2H), 7.37 (s, 1H), 6.82 (d J = 8.6 Hz, 2H), 2.83 (m, 2H), 1.68 (m, 1H). 13C NMR (100 MHz, DMSO-d6) 8 191.59, 158.99, 136.47, 133.96, 129.08, 127.12, 116.50, 28.65, 35 11.03. MSI-MS: 308.3 [M+H]+. With reference to the method in Embodiments 6 to 7, VI10 was prepared by replacing Vil with V10, with a yield of 94.3%. ’H NMR (400 MHz, DMSO-d6) 8 7.67 (s, 2H), 7.27 (s, 1H), 6.61 10 09 24 (s, 2H), 5.95 (s, 2H), 2.82 (s, 2H), 1.51 (s, 1H). 13C NMR (100 MHz, DMSO-d6) 5 188.4, 149.9, 136.9, 132.3, 131.6, 123.8, 114.2, 28.7, 23.2. MSI-MS: 306.4 [M+H]+. With reference to the method in Embodiment 8,110 was prepared by replacing VII1 with VI10, with a yield of 79.8%. 5 Embodiment 10: preparation of 112: poly[(4-{[l,3-(4-amino-3,5-dimethoxyphenyl)methylene]-2,2-bis[(9,10-dihydro-9-oxa-10-phenanthrene-10-oxide)methyl]cyclohexylene]methyl} -2,6-dimethoxyaniline)-phenyl dichlorophosphinate] With reference to the method in Embodiment 1, VI12 was prepared by replacing vanillin with syringaldehyde, with a yield of 99.3%. ’H NMR (400 MHz, DMSO-d6) 5 8.86 (s, 1H), 7.37 (s, 1H), 10 6.74 (s, 2H), 3.83 (s, 6H), 2.81 (m, 2H), 1.51 (m, 1H). 13CNMR(100 MHz, DMSO-d6) 5 190.0, 153.0, 138.8, 135.4, 131.5, 107.9, 56.7, 28.5, 23.0. MSI-MS:427.4 [M+H]+. With reference to the method in Embodiments 6 to 7, VI12 was prepared by replacing VII1 with VI12, with a yield of 90.4%. ’H NMR (400 MHz, DMSO-d6) 5 7.47 (s, 1H), 6.37 (s, 2H), 5.32 (s, 2H), 3.86 (s, 3H), 2.87 (m, 2H), 1.54 (m, 1H). 13CNMR(100 MHz, DMSO-d6) 5 191.6, 149.3, 15 138.3, 133.2, 123.6, 118.6, 104.7, 55.8, 27.6, 26.1. MSI-MS: 425.5 [M+H]+. With reference to the method in Embodiment 8,112 was prepared by replacing VII1 with VI12, with a yield of 78.9%. Embodiment 11: preparation of 12: poly[(4-[(l,4)-5-(4-amino-3-methoxyphenyl)-3,3-bis(9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide)penta-1,4-dienyl] -2-methoxyaniline)-phenyl 20 dichlorophosphinate] With reference to the method in Embodiment 1, VI2 was prepared by replacing cyclohexanone with acetone, with a yield of 95.6%. ’H NMR (400 MHz, DMSO-d6) 5 9.49 (s, 1H), 7.83 (d, 1H), 7.1 l(d, 1H), 7.03(d, 1H), 6.99 (d, 1H), 6.79(d, 1H), 3.86 (s, 3H). 13CNMR(100 MHz, DMSO-d6) 5 190.62, 148.14, 147.28, 142.32, 127.57, 123.3, 122.59, 117.87, 111.72, 56.53. MSI-MS: 327.4 25 [M+H]+. With reference to the method in Embodiments 6 to 7, VI2 was prepared by replacing VII1 with VI2, with a yield of 87.4%. ’H NMR (400 MHz, DMSO-d6) 5 7.82 (d, 1H), 7.34 (d, 1H), 7.03 (d, 1H), 6.78 (d, 1H), 6.67 (d, 1H), 4.95(s, 2H), 3.88(s, 3H). 13C NMR (100 MHz, DMSO-d6) 5 188.6, 148.3, 142.2, 136.5, 125.0, 123.5, 121.9, 117.1, 113.5, 55.8. MSI-MS: 325.4 [M+H]+. 30 With reference to the method in Embodiment 8,12 was prepared by replacing VII1 with VI2, with a yield of 74.8%. Embodiment 12: preparation of 13: poly[(4-[(l,4)-5-(9,10-dihydro-9-oxa-10-phenanthrene-10-oxide)-3,3-bis(4-aminophenyl)penta-l,4-dienyl]-2,6-dimethoxyaniline)-phenyl dichlorophosphinate] 35 With reference to the method in Embodiment 1, VI3 was prepared by replacing vanillin with syringaldehyde and replacing cyclohexanone with acetone, with a yield of 98.2%. 10 09 24 ’HNMR (400 MHz, DMSO-d6) 5 8.75 (s, 1H), 7.83 (d, 1H), 6.99 (d, 1H), 6.74(s, 2H), 3.86 (s, 3H). 13CNMR(100MHz, DMSO-d6) 8 188.6, 148.3, 142.2, 136.5, 125.0, 123.5, 121.9, 107.1, 55.8. MSI-MS: 387.4 [M+H]+. With reference to the method in Embodiments 6 to 7, VI3 was prepared by replacing VII1 5 with VI3, with a yield of 87.4%. ’HNMR (400 MHz, DMSO-d6) 5 7.82 (d, 1H), 7.03 (d, 1H), 6.37 (s, 2H), 5.32 (s, 2H), 3.88(s, 3H). 13CNMR(100MHz, DMSO-d6) 8 188.6, 148.3, 142.2, 124.5, 123.5, 117.1, 103.5, 55.8. MSI-MS: 385.3[M+Na]+. With reference to the method in Embodiment 8,13 was prepared by replacing VII1 with VI3, 10 with a yield of 74.8%. Embodiment 13: preparation of 14: poly[(4-[5-(4-aminophenyl)-2,4-dimethyl-3,3-bis(9,10-dihydro-9-oxa-10-phenanthrene-10-oxide)penta-1,4-dienyl]aniline)-phenyl dichlorophosphinate] With reference to the method in Embodiment 1, VI4 was prepared by replacing cyclohexanone with 3-pentanone and replacing vanillin with p-hydroxybenzaldehyde, with a yield of 96.4%. ’H 15 NMR (400 MHz, DMSO-d6) 5 9.68(s, 1H), 7.45 (d, 2H), 7.37 (s, 1H), 6.59 (d, 2H), 2.34 (s, 3H). 13CNMR(100MHz, CDCls) 5 202.3, 159.6, 138.6, 135.0, 131.3, 128.7, 113.9, 15.0. MSI-MS: 293.3 [M+Na]+. With reference to the method in Embodiments 6 to 7, VI4 was prepared by replacing VII1 with VI4, with a yield of 80.4%. ’H NMR (400 MHz, DMSO-d6) 5 7.66 (d, 2H), 7.37 (s, 1H), 6.37 20 (d, 2H), 5.48 (s, 2H), 2.34 (s, 3H). 13C NMR (100 MHz, DMSO-d6) 8 201.5, 147.4, 146.7, 139.1, 127.6, 125.2, 113.1, 16.4. MSI-MS: 291.4 [M+2H]+. With reference to the method in Embodiment 8,14 was prepared by replacing VII1 with VI4, with a yield of 74.8%. Embodiment 14: preparation of 15: poly[(4-[4-[(l,4)-5-(4- amino-3-methoxyphenyl)-3,3- 25 bis(9,10-dihydro-9-oxa-l 0-phenanthrene-10-oxide)-2,4-dimethyl pentyl-1,4-dienyl]-2-methoxyaniline)-phenyl dichlorophosphinate] With reference to the method in Embodiment 1, VI5 was prepared by replacing cyclohexanone with 3-pentanone, with a yield of 82.7%. 'H NMR (400 MHz, DMSO-d6) 5 9.55 (s, 1H), 7.37 (s, 1H), 7.13 (d, 1H), 7.06 (d, 1H), 6.99 (d, 1H), 3.63 (s, 3H), 2.16 (s, 3H). 13CNMR(100 MHz, 30 DMSO-d6) 8 201.3, 149.1, 147.6, 146.4, 138.5, 127.4, 126.0, 125.8, 115.8,56.1, 16.1. MSI-MS: 355.2 [M+H]+. With reference to the method in Embodiments 6 to 7, VI5 was prepared by replacing VII1 with VI5, with a yield of 82.6%. ’H NMR (400 MHz, DMSO-d6) 8 7.37 (d, 1H), 7.34 (d, 1H), 6.99 (d, 1H), 6.75 (s, 1H), 4.95 (s, 2H), 3.86 (s, 3H), 2.34 (s, 3H). 13C NMR (100 MHz, DMSO-d6) 8 35 198.4, 147.3, 146.9, 136.4, 133.2, 124.6, 121.5, 117.3, 111.2, 56.4, 16.2. MSI-MS: 353.2 [M+2H]+. With reference to the method in Embodiment 8,15 was prepared by replacing VII1 with VI5, with a yield of 72.3%. 10 09 24 Embodiment 15: preparation of 16: poly[(4-[5-(4-amino-3,5-dimethoxyphenyl)-2,4-dimethyl-3,3-bis(9,10-dihydro-9-oxa-10-phenanthrene-10-oxide)penta-1,4-dienyl] -2,6-dimethoxyaniline)-phenyl dichlorophosphinate] With reference to the method in Embodiment 1, VI6 was prepared by replacing vanillin with 5 syringaldehyde and replacing cyclohexanone with 3-pentanone, with a yield of 84.2%. ’H NMR (400 MHz, DMSO-d6) 5 8.68 (s, 1H), 7.38 (s, 1H), 6.76 (s, 2H), 3.85 (s, 6H), 2.56 (d, 3H). 13C NMR (100 MHz, DMSO-d6) 5 192.1, 152.4, 146.9, 139.8, 136.6, 125.2, 106.3, 56.1, 16.2. MSI-MS: 415.5 [M+H]+. With reference to the method in Embodiments 6 to 7, VI6 was prepared by replacing VII1 10 with VI6, with a yield of 80.8%. 'HNMR (400 MHz, DMSO-d6) 5 7.33 (s, 1H), 6.39 (s, 2H), 5.34 (s, 2H), 3.87 (s, 3H), 2.36 (s, 3H). 13CNMR(100 MHz, DMSO-d6) 5 192.1, 150.3, 146.9, 139.8, 122.6, 117.2, 106.3, 55.8, 16.2. MSI-MS: 413.4 [M+H]+. With reference to the method in Embodiment 8,16 was prepared by replacing VII1 with VI6, with a yield of 72.3%. 15 Embodiment 16: preparation ofI7: poly[4-{[2,2-bis(9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide)-3 - [(4-aminophenyl)methylene]cyclopentadienyl]methyl} anilinephenyl dichlorophosphinate] With reference to the method in Embodiment 1, VI7 was prepared by replacing cyclohexanone with cyclopentanone and replacing vanillin with p-hydroxybenzaldehyde, with a yield of 94.3%. ’H 20 NMR (400 MHz, DMSO-d6) 5 9.87 (s, 1H), 7.45 (d, 2H), 7.37 (s, 1H), 6.58 (m, 2H), 3.02 (s, 2H). 13C NMR (100 MHz, DMSO-d6) 5 191.4, 159.6, 145.7, 142.3, 131.5, 129.1, 116.5, 27.8. MSI-MS: 293.1 [M+H]+. With reference to the method in Embodiments 6 to 7, VI7 was prepared by replacing VII1 with VI7, with a yield of 87.2%. ’H NMR (400 MHz, DMSO-d6) 5 7.66 (d, 2H), 7.36 (s, 1H), 6.31 25 (d, 2H), 5.48 (s, 2H), 3.02 (s, 2H). 13C NMR (100 MHz, DMSO-d6) 5 196.4, 149.9, 143.5, 132.5, 131.6, 126.9, 115.4, 29.7. MSI-MS: 291.1 [M+H]+. With reference to the method in Embodiment 8,17 was prepared by replacing VII1 with VI7, with a yield of 72.3%. Embodiment 17: preparation of 18: poly[4-{[l,3-(4-amino-3-methoxyphenyl)methylene]-2,2-30 bis(9,10-dihydro-9-oxa-10-phenanthrene-10-oxide)cyclopentadienyl]methyl} -2 -methoxyaniline phenyl dichlorophosphinate] With reference to the method in Embodiment 1, VI8 was prepared by replacing cyclohexanone with cyclopentanone, with a yield of 98.6%. 'H NMR (400 MHz, DMSO-d6) 5 9.55 (s, 1H), 7.36 (s, 1H), 7.13 (d, 1H), 7.06 (s, 1H), 6.74 (d, 1H), 3.83 (s, 3H), 3.02 (s, 2H). 13CNMR(100 MHz, 35 DMSO-d6) 5 196.4, 149.9, 147.5, 142.1, 132.5, 127.4, 126.5, 126.0, 117.4, 56.1, 29.4. MSI-MS: 353.2 [M+H]+. 10 09 24 With reference to the method in Embodiment 7, VI8 was prepared by replacing VII1 with VI8, with a yield of 90.1%. ’H NMR (400 MHz, DMSO-d6) 5 7.37 (s, 1H), 7.34 (d, 1H), 6.75 (d, 1H), 6.69 (d, 1H), 4.95 (s, 2H), 3.84 (s, 3H) 2.94 (s, 2H). 13CNMR(100 MHz, DMSO-d6) 5 196.1, 147.3, 143.6, 136.5, 132.5, 124.8, 121.9, 117.2, 111.3, 56.1, 29.1. MSI-MS: 351.2 [M+H]+. 5 With reference to the method in Embodiment 8,18 was prepared by replacing VII1 with VI8, with a yield of 77.6%. Embodiment 18: preparation of 19: poly[(4-{[l,3-(4-amino-3,5-dimethoxyphenyl)methylene]-2,2-bis [(9,10-dihydro-9-oxa-10-phenanthrene-10-oxide)methyl]cyclopentadienyl]methyl} -2,6-dimethoxyaniline)-phenyl dichlorophosphinate] 10 With reference to the method in Embodiment 1, VI9 was prepared by replacing vanillin with syringaldehyde and replacing cyclohexanone with cyclopentanone, with a yield of 98.2%. ’H NMR (400 MHz, DMSO-d6) 5 9.12 (s, 1H), 7.40 (s, 1H), 6.74 (s, 2H), 3.85 (s, 6H), 3.15 (s, 2H). 13C NMR (100 MHz, DMSO-d6) 5 195.5, 148.0, 144.3, 136.4, 133.2, 123.5, 107.5, 56.1, 28.9. MSI-MS: 413.5 [M+H]+. 15 With reference to the method in Embodiment 7, VI9 was prepared by replacing III11 with III9, with a yield of 91.6%. ’H NMR (400 MHz, DMSO-d6) 5 7.37 (s, 1H), 6.45 (s, 2H), 5 5.32 (s, 2H), 3.86 (s, 6H), 3.02 (s, 2H). 13C NMR (100 MHz, DMSO-d6) 5 196.6, 148.3, 143.3, 132.8, 122.7, 117.1, 103.5, 55.8, 29.4. MSI-MS: 411.5 [M+Na]+. With reference to the method in Embodiment 8,19 was prepared by replacing VII1 with VI9, 20 with a yield of 76.4%. Embodiment 19: preparation of 11: 4-[(l,4)-5-(4-aminophenyl)-3,3-bis(9,10-dihydro-9-oxa-10-phenanthrene-10-oxide)penta-1,4-dienyl] aniline With reference to the method in Embodiment 1, VII was prepared by replacing vanillin with p-hydroxybenzaldehyde and replacing cyclohexanone with acetone, with a yield of 91.8%. ’H NMR 25 (400 MHz, DMSO-d6) 5 9.58 (s, 1H), 7.82 (d, 1H), 7.45 (d, 2H), 7.03 (d, 1H), 6.59 (d, 2H). 13C NMR (100 MHz, DMSO-d6) 5 189.5, 157.7, 142.2, 130.6, 127.8, 123.3, 115.8. MSI-MS: 267.3 [M+H]+. With reference to the method in Embodiment 7, IV1 was prepared by replacing III11 with III 1, with a yield of 93.7%. ’H NMR (400 MHz, DMSO-d6) 5 7.82 (d, 1H), 7.66 (d, 2H), 7.03(d, 1H), 30 6.31 (d, 2H), 5.48 (s, 2H). 13CNMR(100 MHz, DMSO-d6) 8 188.6, 147.6, 142.2, 129.6, 125.2, 123.3, 114.1. MSI-MS: 265.3 [M+Na]+. With reference to the method in Embodiment 8,11 was prepared by replacing IV11 with IV1, with a yield of 78.6%. Embodiments 20 to 24: preparation of flame-retardant polyurethane material 35 Bio-based aryl diamine flame retardants (111,12,15,18 and 112 respectively) were ground and dried, isocyanate of MDI (0.025 mol, 6.26 g) and premixed polyether polyol of polycaprolactone diol (PCL, weight-average molecular weight of 2000, 0.025 mol, 48 g) were accurately weighed and then poured into different containers for later use, and the flame retardants with a total mass fraction of 10% ( 5.4 g of bio-based aryl diamine, and dimethyl methylphosphonate (DMMP) and lignin in the comparative examples respectively) were accurately weighed. Subsequently, the flame retardants were added into the premixed polyether polyol, stirred at a 5 high speed by an electric stirrer to be evenly mixed, added with the isocyanate quickly, and stirred quickly at the same time to be fully mixed and react. When the reactants reached a milky white state (which lasted for 5 seconds to 10 seconds), the reactants were poured into molds prepared in advance for foaming. After complete foaming, the molds filled with foamed plastic were placed into an oven to be cured at 30°C to 40°C for 24 hours, then the molds were taken out, and flame- 10 retardant polyurethane foamed plastic products were obtained after demolding. The flame retardancy and thermal stability of flame-retardant polyurethane foam samples detected were as shown in Table 2, wherein limiting oxygen indexes (LOI) were determined according to GB / T 17037.1 and carbon residue rates were determined according to GB / T 17144. Table 2 Thermal performances of polyurethanes obtained in Embodiments 20 to 24 and 15 Comparative Examples 10 09 24 Flame retardant LOI TOnset / °C Tio / °C Carbon residue rate / 700°C PHRR / Kw m-2 Embodiment 20 Compound Ill 30.1% 208.23 280.46 26.38 174.28 21 Compound 12 29.82% 193.93 275.01 22.76 179.96 22 Compound 15 24.54% 201.63 279.63 26.36 182.13 23 Compound 18 29.57% 198.76 271.44 23.49 181.78 24 Compound 112 25.12% 197.96 278.39 24.54 180.77 Comparative Example 1 None 18% 176.8 232.7 15.4 277.68 2 DMMP 28.1% 205.6 253.1 25.1 231.2 3 Lignin 23.5% 183.3 268 19.8 184.27 Note: T10 indicated a temperature when a sample loss was 10% in a thermogravimetric analysis test; and Tonset was an initial melting temperature. The LOIs of the flame-retardant polyurethane materials prepared from the compounds II, 13, 14,16,17,19 and 110 by the above method were 23% to 40%. 20 Embodiments 25 to 29: preparation of flame-retardant phenolic foam material: 10 g of lignin-based phenolic resin[1] was added into a beaker, and the beaker was fixed on a stirrer, and then added with 1 g of flame retardants (Ill, 12,15,18 and 112, and ammonium polyphosphate (APP) and lignin in Comparative Examples respectively). 1 g of surfactant Tween- 25 80, 0.6 g of foaming agent n-pentane and 1 g of curing agent (phosphoric acid) were added into a plastic beaker, and a foaming agent in dispersion resin was thoroughly mixed by a high-speed stirrer. Subsequently, a self-made curing agent was added into a reactor under vigorous stirring to obtain a uniform mixture. After mixing, the mixture was immediately poured into a self-made mold (20 cm *20 cm * 5 cm), and subjected to heat preservation in a preheat oven at 80°C for 75 minutes to complete foaming and curing processes. All samples were repeatedly subjected to the operations for three times, and the density of prepared lignin-based phenolic foam was controlled at 45 kg / m3, 5 so as to obtain modified lignin-based phenolic foam. The flame retardancy and thermal stability of the flame-retardant phenolic foam samples detected were as shown in Table 3. 10 09 24 Table 3 Thermal performances of phenolic foams obtained in Embodiments 25 to 29 and Comparative Examples Flame retardant LOI Tio / °C Carbon residue rate (600°C) PHRR / Kw m-2 Embodiment 25 Compound Ill 64.1% 290.46 76.38 174.28 26 Compound 12 52.82% 292.01 62.76 186.96 27 Compound 15 51.54% 295.63 66.36 182.13 28 Compound 18 63.57% 291.44 63.49 181.78 29 Compound 112 52.12% 296.39 70.54 179.77 Comparative Example 4 None 38% 262.7 48.4 277.68 5 APP 55.22% 297.2 61.2 189.31 6 Lignin 50.5% 286.8 61.7 193.27 Note: Tio indicated a temperature when a sample loss was 10% in a thermogravimetric analysis 10 test; and Tonset was an initial melting temperature. Embodiments 30 to 36: LOI test of phenolic foams prepared from flame retardants II, 13,14, 16,17,19 and 110 With reference to the method in Embodiment 25, flame-retardant phenolic foams were prepared by replacing Ill with II, 13,14,16,17,19 and 110, and measured LOI data were as shown 15 in Table 4. Table 4 Flame retardant LOI II 59.2% 13 56.9% 14 54.8% 16 58.3% 17 56.2% 19 54.1% 110 56.3% Reference: 10 09 24 [1] Fanglang Zhou, Zhifeng Zheng, Jing Yang, Haiyan Yang, Jia Deng and Zhengjun Shi. Researches on preparation and performance of lignin-based phenolic resin foam. Chemistry and Industry of Forest Products, 2018, 38(6): 103-109. The embodiments relating to Compounds of Formula II including compounds III -1112 do not 5 form part of the present invention and are included hereinbelow for reference. Embodiment 37: preparation of III 1: poly[3,3'4,4'-benzophenone tetracarboxylic dianhydride-2,6-bis[-(4-amino-3-methoxyphenyl)methylene]cyclohexanone] Under nitrogen protection, 3,3'4,4'-benzophenone tetracarboxylic dianhydride (BTDA, 30.6 g, 0.095 mol) was added into a stirred mixed solution of 2,6-bis[-(4-amino-3- 10 methoxyphenyl)methylene]cyclohexanone IV11 (36.6 g, 0.1 mol) and N-methylpyrrolidone (200 mL) in three times according to a monomer mass ratio of 1 (5.1 g): 2 (10.2 g): 3 (15.3 g) to be subjected to a condensation reaction at 30 °C under a stirring rate of 200 rmp for 8 hours, so as to obtain a polyamic acid solution. BTDA, bio-based diamine and the polyamic acid solution were respectively subjected to FTIR detection by ATR-FTIR, and results were shown in FIG. 11. An 15 absorption peak of the BTDA at 1214 cm1 was a vibration peak caused by a C=O bond in an anhydride group, while the vibration peak disappeared in the PAA solution, and an absorption peak of the bio-based diamine at 3100-3588 cm1 was a vibration peak of amino, while the vibration peak also disappeared in the PAA solution. An absorption peak of the PAA solution at 2739-3055 cm1 was a vibration peak caused by carboxyl, and an absorption peak of the PAA solution at 1688 cm1 20 was a vibration peak caused by a C=O bond in an amide group, which proved the successful polymerization reaction of the bio-based diamine and the BTDA, and the formation of amide and carboxyl. 20 mL of the polyamide acid solution obtained above was evenly coated on a glass plate, and dried on a hot plate at 100 °C for 1 hour. A self-supporting film was obtained by peeling off, and 25 then the supporting film was fixed on a stainless steel fixed fixture, and then dried at 350°C for 2 hours in a hot air dryer to obtain a transparent polyimide film with a thickness of 10 pm. The film was subjected to FTIR characterization by ATR-FTIR, and results were shown in FIG. 12. In the polyimide film, no vibration peak caused by carboxyl was observed at 2739-3055cm-1, and there were vibration peaks caused by a C-N bond in an imide group at 1710cm1 and 1792cm1, which 30 proved the thermal imidization reaction of the PAA solution, the disappearance of carboxyl and the formation of imide group. Embodiment 38: preparation of II10: poly[3,3'4,4'-benzophenone tetracarboxylic dianhydride-2,6-bis[(4-aminophenyl)methylene]cyclohexanone] With reference to the method in Embodiment 37, II10 was prepared by replacing VII1 with 35 VI10. Embodiment 39: preparation of 1112: poly[3,3'4,4'-benzophenone tetracarboxylic dianhydride-2,6-bis[(4-amino-3,5-dimethoxyphenyl)methylene]cyclohexanone] 10 09 24 With reference to the method in Embodiment 37,1112 was prepared by replacing VII1 with VI12. Embodiment 40: preparation of 112: poly[3,3'4,4'-benzophenone tetracarboxylic dianhydride-(1,4)-1,5 -bis(4-amino-3 -methoxyphenyl)penta-1,4-diene-3 -one] 5 With reference to the method in Embodiment 37,112 was prepared by replacing VII1 with VI2. Embodiment 41: preparation of 113: poly[3,3'4,4'-benzophenone tetracarboxylic dianhydride-1,4)-1,5-bis(4-amino-3,5-dimethoxyphenyl)penta-l,4-diene-3-one] With reference to the method in Embodiment 37,113 was prepared by replacing VII1 with 10 VI3. Embodiment 42: preparation of 114: poly[3,3'4,4'-benzophenone tetracarboxylic dianhydride-(1,4)-1,5 -bis(4-aminophenyl)-2,4-dimethylpenta-1,4-diene-3 -one] With reference to the method in Embodiment 37,114 was prepared by replacing VII1 with VI4. 15 Embodiment 43: preparation of 115: poly[3,3'4,4'-benzophenone tetracarboxylic dianhydride-(1,4)-1,5 -bis(4-amino-3 -methoxyphenyl)-2,4-dimethylpenta-1,4-diene-3 -one] With reference to the method in Embodiment 37,115 was prepared by replacing VII1 with VI5. Embodiment 44: preparation of 116: poly[3,3'4,4'-benzophenone tetracarboxylic dianhydride- 20 1,4)-1,5-bis(4-amino-3,5-dimethoxyphenyl)-2,4-dimethylpenta-l,4-diene-3-one] With reference to the method in Embodiment 37,II6 was prepared by replacing VII1 with VI6. Embodiment 45: preparation of 117: poly[3,3'4,4'-benzophenone tetracarboxylic dianhydride-2,5-bis[(4-aminophenyl)methylene]cyclopenta-l-one] 25 With reference to the method in Embodiment 37,117 was prepared by replacing VII1 with VI7. Embodiment 46: preparation of 118: poly[3,3'4,4'-benzophenone tetracarboxylic dianhydride- 2,5-bis[(4-amino-3-methoxyphenyl)methylene]cyclopenta-l-one] With reference to the method in Embodiment 37,118 was prepared by replacing VII1 with 30 VI8. Embodiment 47: preparation of 119: poly[3,3'4,4'-benzophenone tetracarboxylic dianhydride-2,5 -bis [(4-amino-3,5 -dimethoxyphenyl)methylene] cyclopenta-1 -one] With reference to the method in Embodiment 37,119 was prepared by replacing VII1 with VI9. 35 Embodiment 48: preparation of III: poly[3,3'4,4'-benzophenone tetracarboxylic dianhydride-(1,4)-1,5 -bis(4-aminophenyl)penta-1,4-diene-3 -one] 10 09 24 With reference to the method in Embodiment 37, III was prepared by replacing IV11 with IV1. Comparative Example 7: poly[3,3'4,4'-benzophenone tetracarboxylic dianhydride-p-phenylenediamine] 5 With reference to the method in Embodiment 37, the poly[3,3'4,4'-benzophenone tetracarboxylic dianhydride-p-phenylenediamine] was prepared by replacing IV11 with p-phenylenediamine. Comparative Example 8: poly[3,3'4,4'-benzophenone tetracarboxylic dianhydride-m-toluidine] With reference to the method in Embodiment 37, the poly[3,3'4,4'-benzophenone 10 tetracarboxylic dianhydride-m-toluidine] was prepared by replacing IV11 with m-toluidine. Comparative Example 9: poly[3,3'4,4'-benzophenone tetracarboxylic dianhydridediaminodiphenyl ether] With reference to the method in Embodiment 37, the poly[3,3'4,4'-benzophenone tetracarboxylic dianhydride-diaminodiphenyl ether] was prepared by replacing IV11 with 15 diaminodiphenyl ether. Application Example: Various performances of polyimide fdms obtained in Embodiments and Comparative Examples were tested respectively, specific detection methods of glass transition temperature and light transmittance referred to CN111205458 A, and a determination method of a moisture 20 absorption expansion coefficient was as follows. Under the condition of ensuring that the polyimide film did not loosen or collapse, the humidity was adjusted to 3% relative humidity (RH) first, so that the moisture absorption was fully saturated, and a size was measured. Subsequently, the humidity was adjusted to 90% RH, so that the moisture absorption was saturated, and then the size was measured again. By comparing results of 25 the two measurements, a change rate of size at 90% RH was determined when a relative humidity difference was 87%. Detection results were shown in the following Table 5. Table 5 Serial number Moisture absorption expansion coefficient / ppm / RH% 5% weight reduction temperature / °C Glass transition temperature / °C Tensile modulus / Gpa Tensile strength / Mpa Light transmittance / % Embodiment 37 3.9 617 503 10.2 434 63.2 40 3.8 601 492 9.7 414 68.7 41 5.3 622 510 9.5 456 67.2 43 4.4 613 495 9.2 406 69.3 45 5.4 605 510 9.2 447 68.9 47 3.1 614 531 9.4 432 64.3 48 5.9 609 486 8.9 418 71.5 Comparative Example 7 6.8 581 489 7.6 412 52.7 8 6.9 577 462 7.9 398 60.6 9 6.2 565 461 7.4 394 56.9 The above embodiments merely express several embodiments of the present invention, and the descriptions thereof are more specific and detailed, but cannot be understood as a limitation to the scope of the invention patent. It should be noted that those of ordinary skills in the art may make a plurality of transformations and improvements without departing from the conception of the present 5 invention, and these transformations and improvements should all fall within the scope of protection of the present invention. Therefore, the scope of protection of the invention patent should be subjected to the claims appended. CXI

Claims

1. A compound as shown in formula I;iwherein,Ri and R3 are independently selected from -H or -OCH3 respectively;R2 is selected from -H, -CH3, -CH2CH3, -CH2-CH2- or -CH2-CH2-CH2-; and n is selected from 2 to 30.

2. The compound according to claim 1, wherein R2 is selected from -H, -CH3, -CH2-CH2- or-CH2-CH2-CH2-; and preferably, R2 is selected from -H, -CH3 or -CH2-CH2-.

3. The compound according to claim 1, wherein the compound as shown in formula I is any one as shown in formula II to formula 112, wherein n is selected from 2 to 30; preferably, the compound as shown in formula I is any one as shown in formulas II, 13, 16, 17, 18, 110 and Ill; and further preferably, the compound as shown in formula I is one as shown in formula 18 or II 1;Il 12 131415164. A preparation method of the compound as shown in formula I according to claim 1, comprising the following steps of:SI: subjecting a lignin oxidative depolymerization monomer compound as shown in formula III and a bio-based ketone compound as shown in formula IV to an aldol condensation reaction to obtain a coupled bisphenol compound as shown in formula V;S2: subjecting the coupled bisphenol compound as shown in formula V to a phenolic hydroxyl amination reaction to obtain an aryl diamine compound as shown in formula VI;S3: subjecting the aryl diamine compound as shown in formula VI to a substitution reaction with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to obtain a compound as shown in formula VII; andS4: subjecting the compound as shown in formula VII to a solution polycondensation reaction with phenyl dichlorophosphate to obtain the compound as shown in formula I;IIIVIIVIwherein,Ri and R3 are independently selected from -H or -OCH3 respectively;R2 is selected from -H, -CH3, -CH2CH3, -CH2-CH2- or -CH2-CH2-CH2-; preferably, R2 is selected from -H, -CH3, -CH2-CH2- or -CH2-CH2-CH2-; and further preferably, R2 is selected from -H, -CH3 or -CH2-CH2-.

5. The preparation method according to claim 4, wherein, in the step SI, the lignin oxidative depolymerization monomer compound as shown in formula III is any one or a combination of several of vanillin, syringaldehyde and p-hydroxybenzaldehyde; preferably, the bio-based ketone compound as shown in formula IV is any one or a combination of several of acetone, 3-pentanone, cyclopentanone and cyclohexanone; preferably, a solvent of the aldol condensation reaction is an alcohol compound, preferably C1-C6 alcohol, and further preferably ethanol and / or methanol; and preferably, a catalyst of the aldol condensation reaction is an acid catalyst, preferably any one or a combination of several of inorganic acid, organic acid, solid acid and acidic ionic liquid, and further preferably any one or a combination of several of hydrochloric acid, trifluoromethanesulfonic acid, perfluorosulfonic acid resin, sulfuric acid and phosphoric acid.

6. The preparation method according to claim 5, wherein, in the step SI, a molar volume ratio of the lignin oxidative depolymerization monomer compound as shown in formula III and the bio-based ketone compound as shown in formula IV to the solvent in the aldol condensation reaction is 1 mmol: 0.25 mmol to 0.5 mmol: 2 rnL to 5 mL; preferably, a molar ratio of the acid catalyst to the lignin oxidative depolymerization monomer compound is 1: 15 to 25; and preferably, a temperature of the aldol condensation reaction ranges from room temperature to 90°C.

7. The preparation method according to claim 4, wherein, in the step S2, the phenolic hydroxyl amination reaction is that the coupled bisphenol compound as shown in formula V is subjected to a Smiles rearrangement amination reaction without metal catalysis to obtain the aryl diamine compound as shown in formula VI; and preferably, the coupled bisphenol compound as shown in formula V is subjected to an amination reaction with chloroacetamide to obtain a chloroacetamide product as shown in formula X, and then the product is subjected to a Smiles rearrangement reaction to obtain the aryl diamine compound as shown in formula VI;Xpreferably, catalysts of the amination reaction are potassium carbonate and potassium iodide; preferably, a solvent of the amination reaction is any one or a combination of several of acetone,butanone and cyclohexanone; preferably, a molar volume ratio of the coupled bisphenol compound as shown in formula V, the chloroacetamide, the potassium carbonate and the potassium iodide to the solvent in the amination reaction is 1 mmol: 2 mmol to 3 mmol: 2 mmol to 3 mmol: 0.1 mmol to 0.3 mmol: 4 mL to 10 mL; and preferably, a temperature of the amination reaction is 50°C to 90°C; and preferably, a catalyst of the Smiles rearrangement reaction is an alkali catalyst, preferably any one or a combination of several of potassium hydroxide, cesium hydroxide and sodium hydride; preferably, a solvent of the Smiles rearrangement reaction is dimethyl sulfoxide and / or N,N-dimethyl propenyl urea; preferably, a molar volume ratio of the chloroacetamide product and the alkali catalyst to the solvent in the Smiles rearrangement reaction is 1 mmol: 2 mmol to 4 mmol: 15 mL to 25 mL; and preferably, a temperature of the Smiles rearrangement reaction is 90°C to 200°C, preferably 140°C to 200°C, and further preferably 150°C.

8. The preparation method according to claim 4, wherein, in the step S3, the substitution reaction is carried out under nitrogen; preferably, a molar ratio of the aryl diamine compound as shown in formula VI to the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide in the substitution reaction is 1: 4 to 6; preferably, a temperature of the substitution reaction is 180°C to 200°C; and preferably, the substitution reaction lasts for 24 hours to 48 hours.

9. The preparation method according to claim 4, wherein, in the step S4, the solution polycondensation reaction is that the compound as shown in formula VII is subjected to a polymerization reaction with the phenyl dichlorophosphate; preferably, a solvent of the solution polycondensation reaction is N,N-dimethylformamide; preferably, a molar volume ratio of the compound as shown in formula VII, the phenyl dichlorophosphate and the catalyst to the solvent is 1 mmol: 1 mmol to 1.5 mmol: 2 mmol: 5 mL to 10 mL; and preferably, the solution polymerization reaction is carried out under ice bath first and then carried out after heating to 20°C to 30°C, preferably carried out under ice bath for 1 hour to 4 hours first and then carried out after heating to 20°C to 30°C for 5 hours to 7 hours.

10. An application of the compound according to any one of claims 1 to 3 as a flame retardant, wherein, preferably, the application is an application in preparing flame-retardant polyurethane rigid foam or flame-retardant phenolic foam; preferably, when the application is to prepare the flame-retardant polyurethane rigid foam, a dosage of the compound is 1% to 20%, preferably 5% to 15%, and further preferably 10% of a total mass of isocyanate and premixed polyether polyol; preferably, a limiting oxygen index of the flame-retardant polyurethane rigid foam is 23% to 40%; preferably, when the application is to prepare the flame-retardant phenolic foam, a dosage of the compound is 0.1% to 20%, preferably 0.3% to 25%, further preferably 1% to 20%, further preferably 5% to 15%, and most preferably 8% of a total mass of phenolic resin, a surfactant, a foaming agentand a curing agent; and preferably, a limiting oxygen index of the flame-retardant phenolic foam is 50% to 64%.

11. A compound as shown in formula II;wherein,Ri and R3 are independently selected from -H or -OCH3 respectively;R2 is selected from -H, -CH3, -CH2CH3, -CH2-CH2- or -CH2-CH2-CH2-;Ar is selected from tetravalent organic groups with C6-C20 aromatics; and n is selected from 2 to 30.

12. The compound according to claim 11, wherein R2 is selected from -H, -CH3, -CH2-CH2- or -CH2-CH2-CH2-; and preferably, R2 is selected from -H, -CH3 or -CH2-CH2-; and preferably, Ar is selected from any one of the following structural formulas Ari to Ar3;AriAr2 Ar3.

13. The compound according to claim 11, wherein the compound as shown in formula II is any one as shown in formula III to formula 1112, wherein n is selected from 2 to 30;11511614. A preparation method of the compound according to any one of claims 11 to 13, comprising the following steps of: subjecting the aryl diamine compound VI to a condensation reaction with a dianhydride compound to obtain a solution containing a polyamic acid compound VIII;oHOOC COOH R3 R3VI                                   VIIIwherein,Ri and R3 are independently selected from -H or -OCH3 respectively;R2 is selected from -H, -CH3, -CH2CH3, -CH2-CH2- or -CH2-CH2-CH2-; preferably, R2 is selected from -H, -CH3, -CH2-CH2- or -CH2-CH2-CH2-; and further preferably, R2 is selected from -H, -CH3 or -CH2-CH2; andn is selected from 2 to 30.

15. The preparation method according to claim 14, wherein the dianhydride compound comprises 3,3'4,4'-benzophenone tetracarboxylic dianhydride (BTDA), 3,3',4,4-biphenyltetracarboxylic dianhydride (BPDA) and pyromellitic dianhydride (PMDA); and a molar ratio of the aryl diamine compound V to the dianhydride compound is 1: 0.5 to 2, preferably 1: 0.5 to 1, further preferably 1: 0.8 to 1.2, and further preferably 1: 0.95.

16. The preparation method according to claim 14, wherein a solvent of the condensation reaction is a polar aprotic solvent; preferably, the polar aprotic solvent comprises N-methylpyrrolidone; preferably, a dosage ratio of the aryl diamine compound VI to the solvent is 0.01 mol to 0.2 mol / 200mL; preferably, a temperature of the condensation reaction is 20°C to 60°C; and preferably, the condensation reaction lasts for 4 hours to 12 hours.

17. The preparation method according to claim 14, further comprises: subjecting the polyamic acid compound VIII to a thermal imidization reaction at a high temperature to obtain the compound as shown in formula II.

18. A polyimide film, comprising the compound according to any one of claims 11 to 13, or a compound prepared by the method according to any one of claims 14 to 17, wherein, preferably, a moisture absorption expansion coefficient of the polyimide film is below 6 ppm / RH%; preferably, a tensile modulus of the polyimide film is 8 Gpa to 11 Gpa; and preferably, a tensile strength of the polyimide film is 400 Mpa to 450 Mpa.

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