A method for preparing a polyarylate by interfacial polycondensation

Abstract

The application provides a method for preparing polyarylate by an interfacial polycondensation method, and comprises the following steps: dissolving a diphenol monomer in an alkali solution to prepare a bisphenol salt solution, dissolving an interfacial catalyst in the bisphenol salt aqueous phase to obtain an aqueous phase; dissolving aromatic dicarboxylic acid chloride in a halogenated hydrocarbon solvent to obtain an organic phase; slowly adding the organic phase obtained in step S1 into the aqueous phase under stirring, and completing the addition within 10-60 min, and continuing to react for 10-120 min under stirring; precipitating the product, absorbing the precipitated product with the halogenated hydrocarbon solvent to make the liquid phase mainly water and the solid phase a muddy product containing the halogenated hydrocarbon solvent, filtering, washing and drying the obtained muddy product to obtain a powdery product. The method can make the polymer directly precipitate by controlling the solute concentration and the mixing ratio, realizes efficient in-situ removal of the solvent, and realizes "zero segregation, zero crushing and zero distillation" by directly separating the polymer from water through simple filtration.

Description

Technical Field

[0001] This invention belongs to the field of polymer synthesis technology, and in particular relates to a method for preparing polyarylates by interfacial polycondensation. Background Technology

[0002] Traditional interfacial polymerization processes require obtaining a resin solution first, followed by steps such as layering, solvent recovery by distillation, and pulverization. This process is energy-intensive, results in significant solvent loss, and causes severe dust pollution. Therefore, there is an urgent need for a green process that can simultaneously complete solvent removal and product precipitation during the polymerization stage.

[0003] This invention relates to the field of polymer synthesis technology, specifically to a method for achieving in-situ solvent evaporation and direct polymer precipitation during interfacial polymerization, applicable to the green synthesis of condensation-type engineering plastics such as polyarylates (PAR).

[0004] Polyarylates (PARs) are a class of high-performance engineering plastics with aromatic rings in their main chain. They possess high heat resistance (Tg>180℃), excellent mechanical strength, transparency, and flame retardancy, and are widely used in aerospace, electronic packaging, medical devices, and other fields. Their industrial production mainly relies on interfacial polycondensation, which uses bisphenol salts as the aqueous phase and acyl chloride monomers as the organic phase, reacting under the action of a catalyst to generate polymers.

[0005] Traditional processes require obtaining a resin solution first, followed by multiple post-processing steps including layering, washing, precipitation, pulverization, and solvent distillation recovery. The solvent precipitation step, in particular, requires the addition of a large amount of precipitant (such as ethanol) to form a mixed solvent system, which then necessitates distillation separation, resulting in high energy consumption and low solvent recovery rates.

[0006] Although some studies in recent years have attempted to simplify the process (such as CN103965452B), it still requires the addition of a precipitating agent and faces two major problems: the risk of gelation, where the viscosity of the system increases sharply in the later stages of the reaction, leading to uneven local concentration and a wider molecular weight distribution; and the introduction of new impurities by the precipitating agent, requiring additional purification steps. Summary of the Invention

[0007] In view of this, the present invention aims to overcome the defects in the prior art and proposes a method for preparing polyarylates by interfacial polycondensation.

[0008] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0009] This invention provides a method for preparing polyarylates by interfacial polycondensation, comprising the following steps:

[0010] S1: Aqueous phase preparation: The bisphenol monomer is dissolved in an alkaline solution to prepare a bisphenol salt solution. The interfacial catalyst is dissolved in the bisphenol salt solution to obtain an aqueous phase. The molar concentration of the bisphenol salt in the aqueous phase is 0.4-0.75 mol / L.

[0011] S2: Organic phase preparation: Aromatic dicarboxylic acid acyl chloride is dissolved in a halocarbon solvent to obtain an organic phase, wherein the molar concentration of the organic phase is in the ratio of the molar concentration of the bisphenol salt in the aqueous phase to that in the organic phase is 1:(0.95-1.05).

[0012] S3: Interfacial polymerization: Under stirring, the organic phase obtained in step S1 is slowly added to the aqueous phase, and the addition is completed within 10-60 min. The reaction continues under stirring for 10-120 min.

[0013] S4: Product precipitation: The product precipitates in the form of a precipitate. The precipitate absorbs the halogenated hydrocarbon solvent, making the liquid phase mainly water and the solid phase a mud-like product containing the halogenated hydrocarbon solvent. The mud-like product is filtered, washed, and dried to obtain a powdered product.

[0014] Preferably, the molar ratio of the interfacial catalyst to the bisphenol monomer is (0.005-0.02):1.

[0015] Preferably, the volume ratio of the organic phase to the aqueous phase is 1:1.

[0016] Preferably, the bisphenol monomer is one or a mixture of two of bisphenol A and bisphenol S in any proportion.

[0017] Preferably, the alkaline solution is an aqueous solution of one or more of sodium hydroxide, potassium hydroxide, potassium carbonate, and sodium carbonate.

[0018] Preferably, the interfacial catalyst is a quaternary ammonium salt phase transfer catalyst.

[0019] Preferably, the aromatic dicarboxylic acid chloride is one or a mixture of two of terephthaloyl chloride and isophthaloyl chloride in any proportion.

[0020] Preferably, the halogenated hydrocarbon solvent is dichloromethane, dichloroethane, or chloroform.

[0021] Preferably, the reaction temperature in step S3 is 0-40°C.

[0022] The present invention also provides a polyarylate prepared by the above-described interfacial polycondensation method, wherein the weight-average molecular weight Mw of the polyarylate is between 10,000 and 50,000.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] (1) The method of the present invention controls the solute concentration and mixing ratio to make the polymer precipitate directly, thereby achieving efficient in-situ removal of solvent and direct separation from water through simple filtration, achieving "zero separation, zero crushing and zero distillation".

[0025] (2) The PAR resin prepared by the method of the present invention has high thermal oxidation stability, which can meet the requirements of melt processing and can be made into colorless and transparent PAR granules and products, which is conducive to expanding the application of polyarylate in fields with high material performance requirements such as aviation, automobile, electronics, LED lighting, medical devices and energy transportation. Detailed Implementation

[0026] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0027] In this document, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0028] In this document, when values ​​are described as ranges, it should be understood that such disclosure includes disclosure of all possible subranges within that range, as well as the specific numerical values ​​falling within that range, regardless of whether the specific numerical value or specific subrange is explicitly specified.

[0029] In this article, the terms "multiple" or "more than" are used unless otherwise specified, referring to a quantity greater than or equal to 2. For example, "one or more" means one or more types.

[0030] In this document, the terms "preferred" and "more preferred" are used only to describe implementation methods or embodiments with better effects, and should be understood as not constituting a limitation on the scope of protection of this invention.

[0031] In this document, terms such as "further" are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of this invention.

[0032] In this article, the term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0033] In this document, the term "about" means a specified value of + / - 10%, preferably + / - 5%, and more preferably + / - 1%.

[0034] In this article, the terms “include,” “including,” “have,” “contain,” etc., are all open-ended terms, meaning that they include but are not limited to.

[0035] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar to or equivalent to those described herein may be used in the implementation or testing of this invention.

[0036] The present invention will be described in detail below with reference to the embodiments.

[0037] Example 1

[0038] A method for preparing and separating polyarylates, comprising the following steps:

[0039] (1) Preparation of aqueous phase: Dissolve 22.8g of bisphenol A in NaOH aqueous solution, wherein the mass of NaOH is 8.8g and the volume of water is 220mL, and then add 0.184g of triethylbenzylammonium chloride to obtain the aqueous phase.

[0040] (2) Preparation of organic phase: Dissolve 20.3g of terephthaloyl chloride in 220mL of dichloromethane to obtain organic phase.

[0041] (3) Interfacial polymerization: The organic phase was added to the aqueous phase under stirring at 25°C, and the addition was completed within 1 hour. After the addition was completed, the reaction continued for 45 minutes.

[0042] (4) Product precipitation: Polyarylate is suspended in the system in the form of precipitate, filtered and dried to obtain the product, with a weight average molecular weight Mw between 10,000 and 50,000.

[0043] (5) Solvent recovery: Volatile solvents are directly obtained from the recovery unit and recycled.

[0044] Example 2

[0045] A method for preparing and separating polyarylates, comprising the following steps:

[0046] (1) Preparation of aqueous phase: Dissolve 25g of bisphenol S in NaOH aqueous solution, where the mass of NaOH is 10g and the volume of water is 250mL, and then add 0.184g of triethylbenzylammonium chloride to obtain the aqueous phase.

[0047] (2) Preparation of organic phase: Dissolve 20.3g of isophthaloyl chloride in 250mL of dichloroethane to obtain organic phase.

[0048] (3) Interfacial polymerization: The organic phase was added to the inorganic phase under stirring at 0°C, and the addition was completed within 1 hour. After the addition was completed, the reaction continued for 30 minutes.

[0049] (4) Product precipitation: The polyarylate is suspended in the system in the form of clumps. After filtration and drying, the product is obtained with a weight-average molecular weight (Mw) between 10,000 and 50,000.

[0050] (5) Solvent recovery: Volatile solvents are directly obtained from the recovery unit and recycled.

[0051] Example 3

[0052] A method for preparing and separating polyarylates, comprising the following steps:

[0053] (1) Preparation of aqueous phase: Dissolve 11.4g of bisphenol A and 12.5g of bisphenol S in NaOH aqueous solution, wherein the mass of NaOH is 10g and the volume of water is 167mL, and then add 0.369g of triethylbenzylammonium chloride to obtain the aqueous phase.

[0054] (2) Preparation of organic phase: Dissolve 21.3g of terephthaloyl chloride in 167mL of chloroform to obtain organic phase.

[0055] (3) Interfacial polymerization: The organic phase was added to the inorganic phase under stirring at 25°C, and the addition was completed within 1 hour. After the addition was completed, the reaction continued for 60 minutes.

[0056] (4) Product precipitation: After reacting for 60 min, the polyarylate was suspended in the system in the form of clumps. After filtration and drying, the product was obtained with a weight-average molecular weight (Mw) between 10,000 and 50,000.

[0057] (5) Solvent recovery: Volatile solvents are directly obtained from the recovery unit and recycled.

[0058] Example 4

[0059] A method for preparing and separating polyarylates, comprising the following steps:

[0060] (1) Preparation of aqueous phase: Dissolve 22.8g of bisphenol A in NaOH aqueous solution, wherein the mass of NaOH is 9.2g and the volume of water is 192mL, and then add 0.277g of triethylbenzylammonium chloride to obtain the aqueous phase.

[0061] (2) Preparation of organic phase: Dissolve 10.1 g of terephthaloyl chloride and 10.1 g of isophthaloyl chloride in 192 mL of dichloromethane to obtain organic phase.

[0062] (3) Interfacial polymerization: The organic phase was added to the inorganic phase under stirring at 15°C, and the addition was completed within 1 hour. After the addition was completed, the reaction continued for 30 minutes.

[0063] (4) Product precipitation: The polyarylate is suspended in the system in the form of clumps. After filtration and drying, the product is obtained with a weight-average molecular weight (Mw) between 10,000 and 50,000.

[0064] (5) Solvent recovery: Volatile solvents are directly obtained from the recovery unit and recycled.

[0065] Example 5

[0066] (1) Preparation of aqueous phase: Dissolve 38g of bisphenol A in NaOH aqueous solution, wherein the mass of NaOH is 14.67g and the volume of water is 220mL, and then add 0.184g of triethylbenzylammonium chloride to obtain the aqueous phase.

[0067] (2) Preparation of organic phase: Dissolve 33.5g of terephthaloyl chloride in 220mL of dichloromethane to obtain organic phase.

[0068] (3) Interfacial polymerization: The organic phase was added to the aqueous phase under stirring at 25°C, and the addition was completed within 1 hour. After the addition was completed, the reaction continued for 45 minutes.

[0069] (4) Product precipitation: Polyarylate is suspended in the system in the form of precipitate, filtered and dried to obtain the product, with a weight average molecular weight Mw between 10,000 and 50,000.

[0070] (5) Solvent recovery: Volatile solvents are directly obtained from the recovery unit and recycled.

[0071] Example 6

[0072] (1) Preparation of aqueous phase: Dissolve 22.8g of bisphenol A in NaOH aqueous solution, wherein the mass of NaOH is 8.8g and the volume of water is 220mL, and then add 0.184g of triethylbenzylammonium chloride to obtain the aqueous phase.

[0073] (2) Preparation of organic phase: Dissolve 20.3g of terephthaloyl chloride in 220mL of dichloromethane to obtain organic phase.

[0074] (3) Interfacial polymerization: The organic phase was added to the aqueous phase under stirring at 25°C, and the addition was completed within 1 hour. After the addition was completed, the reaction continued for 45 minutes.

[0075] (4) Product precipitation: Polyarylate is suspended in the system in the form of precipitate, filtered and dried to obtain the product, with a weight average molecular weight Mw between 10,000 and 50,000.

[0076] (5) Solvent recovery: Volatile solvents are directly obtained from the recovery unit and recycled.

[0077] Example 7

[0078] A method for preparing and separating polyarylates, comprising the following steps:

[0079] (1) Preparation of aqueous phase: Dissolve 23.9g of bisphenol A in NaOH aqueous solution, where the mass of NaOH is 8.8g and the volume of water is 220mL. Then add 0.184g of triethylbenzylammonium chloride to obtain the aqueous phase.

[0080] (2) Preparation of organic phase: Dissolve 20.3g of terephthaloyl chloride in 220mL of dichloromethane to obtain organic phase.

[0081] (3) Interfacial polymerization: The organic phase was added to the aqueous phase under stirring at 25°C, and the addition was completed within 10 min. After the addition was completed, the reaction continued for 120 min.

[0082] (4) Product precipitation: Polyarylate is suspended in the system in the form of precipitate, filtered and dried to obtain the product, with a weight average molecular weight Mw between 10,000 and 50,000.

[0083] (5) Solvent recovery: Volatile solvents are directly obtained from the recovery unit and recycled.

[0084] Example 8

[0085] A method for preparing and separating polyarylates, comprising the following steps:

[0086] (1) Preparation of aqueous phase: Dissolve 22.8g of bisphenol A in NaOH aqueous solution, wherein the mass of NaOH is 8.8g and the volume of water is 220mL, and then add 0.184g of triethylbenzylammonium chloride to obtain the aqueous phase.

[0087] (2) Preparation of organic phase: Dissolve 21.3g of terephthaloyl chloride in 220mL of dichloromethane to obtain organic phase.

[0088] (3) Interfacial polymerization: The organic phase was added to the aqueous phase under stirring at 25°C, and the addition was completed within 10 min. After the addition was completed, the reaction continued for 120 min.

[0089] (4) Product precipitation: Polyarylate is suspended in the system in the form of precipitate, filtered and dried to obtain the product, with a weight average molecular weight Mw between 10,000 and 50,000.

[0090] (5) Solvent recovery: Volatile solvents are directly obtained from the recovery unit and recycled.

[0091] Comparative Example 1

[0092] In Example 1, the volumes of water and dichloromethane were changed to 440 mL, while all other volumes remained the same. The yield of the polyarylate was extremely low, only 50-60%.

[0093] Comparative Example 2

[0094] If the amount of catalyst in Example 1 is changed to 0.09g, while the rest remains unchanged, no precipitate will be obtained.

[0095] Comparative Example 3

[0096] If the amount of catalyst in Example 1 is changed to 0.38g, while the rest remains unchanged, the resulting product is extremely brittle and does not meet the requirements.

[0097] Comparative Example 4

[0098] The amount of bisphenol A added in Example 1 was changed to 25.1 g, while the rest remained unchanged. The polyarylate obtained by this method was too brittle and did not meet the processing requirements.

[0099] Comparative Example 5

[0100] The amount of terephthaloyl chloride added in Example 1 was changed to 22.8g, while the rest remained unchanged. The polyarylate obtained by this method was too brittle and did not meet the processing requirements.

[0101] Comparative Example 6

[0102] Using water as a precipitant, the amounts of dichloromethane and water in Example 4 were changed to 384 mL, while other parameters remained unchanged. This resulted in a separate solution without precipitation. The lower layer of solution was collected, added to excess ethanol, and filtered to obtain a white precipitate powder, which is the polyarylate product. The molecular weight (Mw) of the polyarylate obtained by this method does not exceed 10,000.

[0103] 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 within the protection scope of the present invention.

Claims

1. A method for preparing polyarylates via interfacial polycondensation, characterized in that: Includes the following steps: S1: Aqueous phase preparation: The bisphenol monomer is dissolved in an alkaline solution to prepare a bisphenol salt solution, and the interfacial catalyst is dissolved in the bisphenol salt solution to obtain an aqueous phase. The molar concentration of the bisphenol salt in the aqueous phase is 0.4-0.75 mol / L. S2: Organic phase preparation: Aromatic dicarboxylic acid acyl chloride is dissolved in a halocarbon solvent to obtain an organic phase, wherein the molar concentration of the organic phase is in the ratio of the molar concentration of the bisphenol salt in the aqueous phase to that in the organic phase is 1:(0.95-1.05). S3: Interfacial polymerization: Under stirring, the organic phase obtained in step S1 is slowly added to the aqueous phase, and the addition is completed within 10-60 min. The reaction continues under stirring for 10-120 min. S4: Product precipitation: The product precipitates in the form of a precipitate. The precipitated product absorbs the halogenated hydrocarbon solvent, making the liquid phase mainly water and the solid phase a mud-like product containing the halogenated hydrocarbon solvent. The mud-like product is filtered, washed, and dried to obtain a powdered product.

2. The method for preparing polyarylates by interfacial polycondensation according to claim 1, characterized in that: The molar ratio of the interfacial catalyst to the diphenol monomer is (0.005-0.02):

1.

3. The method for preparing polyarylates by interfacial polycondensation according to claim 1, characterized in that: The volume ratio of the organic phase to the aqueous phase is 1:

1.

4. The method for preparing polyarylates by interfacial polycondensation according to claim 1, characterized in that: The bisphenol monomer is one or a mixture of two of bisphenol A and bisphenol S in any proportion.

5. The method for preparing polyarylates by interfacial polycondensation according to claim 1, characterized in that: The alkaline solution is an aqueous solution of one or more of sodium hydroxide, potassium hydroxide, potassium carbonate, and sodium carbonate.

6. The method for preparing polyarylates by interfacial polycondensation according to claim 1, characterized in that: The interfacial catalyst is a quaternary ammonium salt phase transfer catalyst.

7. The method for preparing polyarylates by interfacial polycondensation according to claim 1, characterized in that: The aromatic dicarboxylic acid chloride is one or a mixture of two of terephthaloyl chloride and isophthaloyl chloride in any proportion.

8. The method for preparing polyarylates by interfacial polycondensation according to claim 1, characterized in that: The halogenated hydrocarbon solvent is dichloromethane, dichloroethane, or chloroform.

9. The method for preparing polyarylates by interfacial polycondensation according to claim 1, characterized in that: The reaction temperature in step S3 is 0-40℃.

10. The polyarylate prepared by the interfacial polycondensation method according to any one of claims 1-9 is characterized in that: The weight-average molecular weight (Mw) of the polyarylate is between 10,000 and 50,000.