Preparation method of low-cost polyarylene ether nitrile

Abstract

The invention discloses a preparation method of low-cost polyarylene ether nitrile, and belongs to the technical field of special polymer synthesis. The method comprises the following steps: adding 2, 4-dichlorobenzonitrile, bisphenol A, a catalyst and an antioxidant into an ionic liquid; and reacting at 110-180 DEG C for 7-12 hours to obtain the low-cost polyarylene ether nitrile. The use amount of the antioxidant is 0.2-1.0% of the mass of the bisphenol A; the ionic liquid is a mixed solvent of 1-butyl-3-methylimidazolium tetrafluoroborate and toluene, the dosage of the 1-butyl-3-methylimidazolium tetrafluoroborate is 1.2-2.5 times of the mass sum of the 2, 4-dichlorobenzonitrile, the bisphenol A and the catalyst, the volume ratio of the 1-butyl-3-methylimidazolium tetrafluoroborate to the toluene is (2-5): 1, and the antioxidant is triphenyl phosphate. The cost of the prepared polyarylene ether nitrile is about 1 / 2 of that of the polyarylene ether nitrile prepared from 2, 6-dichlorobenzonitrile, but the mechanical properties of the polyarylene ether nitrile are close to those of the polyarylene ether nitrile prepared from 2, 6-dichlorobenzonitrile.

Description

Technical Field

[0001] The present invention relates to the technical field of special polymer synthesis, and in particular to a method for preparing low-cost polyarylethernitrile. Background Art

[0002] The reaction mechanisms of poly(arylene ether nitrile)s are primarily electrophilic and nucleophilic substitution. Due to the harsh reaction conditions of electrophilic substitution, it was gradually replaced by nucleophilic substitution. Currently, most reports on the synthesis of poly(arylene ether nitrile)s in China employ a one-step synthesis process, obtaining poly(arylene ether nitrile)s and their copolymers via nucleophilic substitution. Aromatic diphenols and 2,6-dihalobenzonitrile are first dissolved in a polar aprotic solvent. Under base catalysis, the poly(arylene ether nitrile)s are synthesized through salt formation, dehydration, polycondensation, and purification stages to ultimately obtain the poly(arylene ether nitrile).

[0003] For example, patent application number CN202310224451.2 discloses a method for synthesizing poly(arylene ether nitrile) in one step using a DMAC solvent, comprising the following steps: a. Feeding: Under a protective atmosphere, feed the raw materials dihydric phenol, 2,6-dichlorobenzonitrile, alkali metal salt and DMAC solvent at one time, mix them evenly, and obtain a mixed material; wherein the DMAC solvent is N,N-dimethylacetamide.

[0004] b. Salt-forming reaction: keep the mixed materials at 120-160°C for 0.5-1h to carry out salt-forming reaction.

[0005] c. Dehydration: The material after the salt formation reaction is heated and controlled to 170-190°C for 3-4 hours to remove the DMAC solvent and the by-product water by azeotropic distillation.

[0006] d. Polycondensation reaction: Raise the temperature to 190-200°C and continue for 2-4 hours to complete the polymerization reaction.

[0007] e. Terminate the reaction to obtain polyarylene ether nitrile resin.

[0008] This patent uses 2,6-dichlorobenzonitrile as the raw material and produces polyarylethernitrile resin through salt formation, dehydration and polycondensation. Its weight-average molecular weight is greater than 110,000 and its flexural strength is greater than 100 MPa.

[0009] The applicant discovered that if 2,4-dichlorobenzonitrile (much cheaper than 2,6-dichlorobenzonitrile) is used as the raw material, under specific conditions, polyarylethernitrile can be produced with mechanical properties close to those of the prior art, but at a much lower cost (about 1 / 2 lower). Summary of the Invention

[0010] The present invention discloses a method for preparing a low-cost poly(arylene ether nitrile), comprising: adding 2,4-dichlorobenzonitrile, bisphenol A, a catalyst, and an antioxidant to an ionic liquid; and reacting the mixture at 110-180°C for 7-12 hours under nitrogen protection to obtain the low-cost poly(arylene ether nitrile). The molar ratio of 2,4-dichlorobenzonitrile to bisphenol A is 1:0.98-1.02, the molar ratio of the catalyst to 2,4-dichlorobenzonitrile is 1.5-2.0:1, and the amount of the antioxidant is 0.2-1.0% of the mass of the bisphenol A. The ionic liquid is a mixed solvent of 1-butyl-3-methylimidazolium tetrafluoroborate and toluene. The amount of 1-butyl-3-methylimidazolium tetrafluoroborate is 1.2-2.5 times the combined mass of 2,4-dichlorobenzonitrile, bisphenol A, and the catalyst. The volume ratio of 1-butyl-3-methylimidazolium tetrafluoroborate to toluene is 2-5:1. The antioxidant is triphenyl phosphite. The catalyst is selected from potassium carbonate or sodium carbonate, preferably potassium carbonate.

[0011] The catalyst and ionic liquid composite system, with the ionic liquid acting as a phase transfer catalyst, accelerates the nucleophilic substitution reaction between monomers, shortening the reaction time by over 30%. Antioxidants provide in-situ protection, inhibiting the oxidation of diphenols and increasing the product color (L* value) to 83 or above. Toluene serves as both a solvent and a dehydrating agent.

[0012] Preferably, step (2) specifically comprises: under nitrogen protection, a first stage: prepolymerization at 110-125°C for 1-2 hours with dehydration; a second stage: heating to 155-160°C and continuing reaction for 3-5 hours; and a third stage: heating to 165-180°C and continuing reaction for 3-5 hours. Gradient temperature control dehydration allows the product to have a viscosity-average molecular weight (Mv) greater than 50,000.

[0013] Preferably, the amount of 1-butyl-3-methylimidazolium tetrafluoroborate is 1.5 times the sum of the mass of 2,4-dichlorobenzonitrile, bisphenol A and the catalyst, the volume ratio of 1-butyl-3-methylimidazolium tetrafluoroborate to toluene is 3:1, and the amount of the antioxidant is 0.5% of the mass of bisphenol A.

[0014] Furthermore, after the reaction is completed, water is added, and the solid-liquid separation, washing, and drying are performed to obtain low-cost polyarylene ether nitrile.

[0015] Preferably, the low-cost preparation method of poly (arylene ether nitrile) provided by this patent comprises: (1) 2,4-dichlorobenzonitrile, bisphenol A, a catalyst, and an antioxidant are added to an ionic liquid. The molar ratio of 2,4-dichlorobenzonitrile to bisphenol A is 1:0.98-1.02, the molar ratio of the catalyst to 2,4-dichlorobenzonitrile is 1.5-2.0:1, and the amount of the antioxidant is 0.5% of the mass of bisphenol A. The ionic liquid is a mixed solvent of 1-butyl-3-methylimidazolium tetrafluoroborate and toluene. The amount of 1-butyl-3-methylimidazolium tetrafluoroborate is 1.5 times the sum of the mass of 2,4-dichlorobenzonitrile, bisphenol A, and the catalyst. The volume ratio of 1-butyl-3-methylimidazolium tetrafluoroborate to toluene is 3:1. The antioxidant is triphenyl phosphite, and the catalyst is potassium carbonate.

[0016] (2) Under nitrogen protection, the first stage: prepolymerization at 110-125 ° C for 1-2 hours to dehydrate; the second stage: heating to 155-160 ° C and continuing the reaction for 3-5 hours; the third stage: heating to 165-180 ° C and continuing the reaction for 3-5 hours.

[0017] (3) After the reaction is completed, water is added, and the solid-liquid separation, washing, and drying are performed to obtain low-cost polyarylene ether nitrile.

[0018] The parameters of the low-cost polyarylethernitrile prepared in this patent are: viscosity average molecular weight (Mv) of 50,000-120,000, PDI=1.5-3.5, T5%=460-505, tensile strength of 80-100 MPa, tensile modulus of 2.0-3.5 GPa, and elongation at break of 4.5-9.1%.

[0019] The mechanical properties of the poly(arylether nitrile) prepared by this patent are close to those of the poly(arylether nitrile) prepared using 2,6-dichlorobenzonitrile as raw material, but the cost is much lower (only about 1 / 2 of the cost of the poly(arylether nitrile) prepared using 2,6-dichlorobenzonitrile); the product color (L* value) is increased to 83, and the viscosity-average molecular weight (Mv) is greater than 50,000. DETAILED DESCRIPTION

[0020] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention are described in further detail below.

[0021] Example 1: (1) In a reaction kettle, add 9.5 g (7.85 mL) of 1-butyl-3-methylimidazolium tetrafluoroborate, 1.95 g (10 mmol) of 2,4-dichlorobenzonitrile, 2.28 g (10 mmol) of bisphenol A, 2.07 g (15 mmol) of potassium carbonate, 2.65 mL of toluene, and 11.4 mg of triphenyl phosphite.

[0022] (2) Nitrogen is passed through to exclude oxygen, the first stage: prepolymerization at 120°C for 1.5 hours for dehydration; the second stage: heating to 160°C and continuing the reaction for 4 hours; the third stage: heating to 180°C and continuing the reaction for 4 hours.

[0023] (3) After the reaction is completed, the reaction solution is cooled and poured into deionized water to precipitate the polymer, which is then filtered, washed with ethanol, and vacuum-dried at 80°C for 24 hours to obtain the product.

[0024] After testing, the product color (L* value) is 84 and the viscosity average molecular weight (Mv) is 52700.

[0025] Example 2: (1) In a reaction kettle, add 10.2 g (8.43 mL) of 1-butyl-3-methylimidazolium tetrafluoroborate, 1.95 g (10 mmol) of 2,4-dichlorobenzonitrile, 2.28 g (10 mmol) of bisphenol A, 2.21 g (16 mmol) of potassium carbonate, 2.9 mL of toluene, and 10 mg of triphenyl phosphite.

[0026] (2) Nitrogen is passed through to remove oxygen. The first stage is prepolymerization at 118°C for 2 hours for dehydration. The second stage is heating to 155°C and continuing the reaction for 4 hours. The third stage is heating to 165°C and continuing the reaction for 4 hours.

[0027] (3) After the reaction is completed, the reaction solution is cooled and poured into deionized water to precipitate the polymer, which is then filtered, washed with ethanol, and vacuum-dried at 80°C for 24 hours to obtain the product.

[0028] After testing, the product color (L* value) is 83 and the viscosity average molecular weight (Mv) is 56,000.

[0029] Example 3: (1) In a reaction kettle, add 9.5 g (7.85 mL) of 1-butyl-3-methylimidazolium tetrafluoroborate, 1.95 g (10 mmol) of 2,4-dichlorobenzonitrile, 2.28 g (10 mmol) of bisphenol A, 2.49 g (18 mmol) of potassium carbonate, 3.62 mL of toluene, and 9.3 mg of triphenyl phosphite.

[0030] (2) Nitrogen is passed through to exclude oxygen, the first stage: prepolymerization at 120°C for 1.5 hours for dehydration; the second stage: heating to 160°C and continuing the reaction for 4 hours; the third stage: heating to 180°C and continuing the reaction for 3 hours.

[0031] (3) After the reaction is completed, the reaction solution is cooled and poured into deionized water to precipitate the polymer, which is then filtered, washed with ethanol, and vacuum-dried at 80°C for 24 hours to obtain the product.

[0032] After testing, the product color (L* value) is 86 and the viscosity average molecular weight (Mv) is 55400.

[0033] Comparative Example 1 The process is basically the same as that of Example 1, except that: N-methylpyrrolidone is used as a solvent instead of 1-butyl-3-methylimidazolium tetrafluoroborate, and the amount of N-methylpyrrolidone used is 4 times that of the reaction raw material.

[0034] Comparative Example 2 The process was basically the same as that of Example 1, except that the reaction temperature was kept constant at 170° C. The product color (L* value) was 82 and the viscosity average molecular weight (Mv) was 36,200.

[0035] Comparative Example 3 The process with application number CN202310224451.2 is adopted, with 2,6-dichlorobenzonitrile and bisphenol A as raw materials.

[0036] The comparative effects of this patent, the comparative examples and the commercially available products are shown in Table 1: Table 1

[0037] As can be seen from Table 1, the mechanical properties of the poly(arylene ether nitrile) prepared in this patent are similar to those of the same type available on the market.

[0038] Comparative Example 4 The process was essentially the same as in Example 1, except that no antioxidant was added. Testing revealed that the product had a color (L* value) of 72 and a viscosity-average molecular weight (Mv) of 47,530. The tensile strength was 94 MPa, the tensile modulus was 2.7 GPa, and the elongation at break was 5.2%.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a low-cost poly(arylene ether nitrile), characterized in that: The method comprises: adding 2,4-dichlorobenzonitrile, bisphenol A, a catalyst and an antioxidant into an ionic liquid; reacting at 110-180° C. for 7-12 hours under nitrogen protection to obtain a low-cost polyarylene ether nitrile; The molar ratio of 2,4-dichlorobenzonitrile to bisphenol A is 1:0.98-1.02, the molar ratio of the catalyst to 2,4-dichlorobenzonitrile is 1.5-2.0:1, and the amount of the antioxidant is 0.2-1.0% of the mass of bisphenol A. The ionic liquid is a mixed solvent of 1-butyl-3-methylimidazolium tetrafluoroborate and toluene, the 1-butyl-3-methylimidazolium tetrafluoroborate is 1.2-2.5 times the sum of the mass of 2,4-dichlorobenzonitrile, bisphenol A and the catalyst, the volume ratio of the 1-butyl-3-methylimidazolium tetrafluoroborate to toluene is 2-5:1, the antioxidant is triphenyl phosphite, and the catalyst is selected from potassium carbonate or sodium carbonate.

2. The method for preparing low-cost polyarylene ether nitrile according to claim 1, wherein Step (2) specifically includes: under nitrogen protection, the first stage: prepolymerization at 110-125° C. for 1-2 hours for dehydration; the second stage: heating to 155-160° C. and continuing the reaction for 3-5 hours; the third stage: heating to 165-180° C. and continuing the reaction for 3-5 hours.

3. The method for preparing low-cost polyarylene ether nitrile according to claim 1, wherein The catalyst is potassium carbonate.

4. The method for preparing low-cost polyarylene ether nitrile according to claim 1, wherein The amount of the 1-butyl-3-methylimidazolium tetrafluoroborate is 1.5 times the sum of the mass of 2,4-dichlorobenzonitrile, bisphenol A and the catalyst. The volume ratio of the 1-butyl-3-methylimidazolium tetrafluoroborate to toluene is 3:

1. The amount of the antioxidant is 0.5% of the mass of bisphenol A.

5. The method for preparing low-cost polyarylene ether nitrile according to claim 1, wherein After the reaction is completed, water is added, and the solid-liquid separation, washing, and drying are performed to obtain low-cost polyarylene ether nitrile.

6. The method for preparing low-cost polyarylene ether nitrile according to claim 1, wherein The method comprises: (1) Adding 2,4-dichlorobenzonitrile, bisphenol A, a catalyst and an antioxidant to an ionic liquid, wherein the molar ratio of 2,4-dichlorobenzonitrile to bisphenol A is 1:0.98-1.02, the molar ratio of the catalyst to 2,4-dichlorobenzonitrile is 1.5-2.0:1, the amount of the antioxidant is 0.5% of the mass of bisphenol A, the ionic liquid is a mixed solvent of 1-butyl-3-methylimidazolium tetrafluoroborate and toluene, the amount of the 1-butyl-3-methylimidazolium tetrafluoroborate is 1.5 times the sum of the mass of 2,4-dichlorobenzonitrile, bisphenol A and the catalyst, the volume ratio of the 1-butyl-3-methylimidazolium tetrafluoroborate to toluene is 3:1, the antioxidant is triphenyl phosphite, and the catalyst is potassium carbonate; (2) Under nitrogen protection, the first stage: prepolymerization at 110-125 ° C for 1-2 hours for dehydration; the second stage: heating to 155-160 ° C and continuing the reaction for 3-5 hours; the third stage: heating to 165-180 ° C and continuing the reaction for 3-5 hours; (3) After the reaction is completed, water is added, and the solid-liquid separation, washing, and drying are performed to obtain low-cost polyarylene ether nitrile.

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