Preparation method and device of low-molecular-weight dihydroxy-terminated polyphenyl ether

Abstract

According to the preparation method and device of the low-molecular-weight dihydroxy-terminated polyphenyl ether, provided by the invention, the reaction is more complete through gradient polymerization reaction, the generation of reaction byproducts is greatly reduced, and the yield is higher; a segmented chelation mode is adopted, so that the residual content of the catalyst is greatly reduced, and the high applicability of the product in rear-end application is remarkably improved; by applying the special device disclosed by the invention, the reaction is more sufficient and uniform, the molecular weight distribution of the product is narrow, the quality uniformity is good, and the compatibility with downstream application is better.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer material synthesis, in particular to a preparation method and device of low molecular weight double-end hydroxyl polyphenyl ether (PPO-2OH for short). BACKGROUND

[0002] Low molecular weight double-end hydroxyl polyphenyl ether (PPE-2OH for short) is a new type of modified low molecular weight polyphenyl ether resin, which well balances the needs of low dielectric constant and loss factor, has stronger toughness and higher thermal stability; the PPE-2OH molecular chain end is connected with a high-reactivity hydroxyl group, and is a polyphenyl ether oligomer prepared by further functionalization modification of an alkenyl group, which is a more homogeneous dielectric and is widely used in high-end fields such as electronic circuit substrates.

[0003] There are two methods for preparing low molecular weight double-end hydroxyl polyphenyl ether in the prior art, one is redistribution method, that is, under the condition of adding a free radical initiator, high molecular weight polyphenyl ether is subjected to redistribution reaction with various phenolic derivatives to obtain polyphenyl ether with hydroxyl groups at both ends of the molecular chain; the product produced by this method has uneven molecular weight distribution, it is difficult to continuously control the molecular weight during the reaction, and the molecular structure of the polymer is easy to be embedded with initiator groups to affect the product performance; and the other method commonly used in the prior art is oxidation copolymerization method, that is, two monomers are directly oxidized and copolymerized under certain conditions; compared with the redistribution method, the low molecular weight polyphenyl ether synthesized by the oxidation copolymerization method has simpler reaction and higher yield.

[0004] In the paper “Preparation and characterization of low molecular weight polyphenyl ether” published in Guangdong Chemical, No. 20, 2019, it is mentioned that the low molecular weight polyphenyl ether is prepared by the redistribution method, specifically by introducing a chain transfer agent in the redistribution reaction system of polyphenyl ether and dibasic phenol, and the effect of the chain transfer agent on the redistribution reaction of polyphenyl ether is explored. However, the specific performance of the low molecular weight polyphenyl ether prepared by the redistribution method is not described in the document, and only in the summary and prospect part of the paper it is stated that “but the amount of chain transfer agent and the specific mechanism of action need to be further studied”. However, it is known from common knowledge that the low molecular weight polyphenyl ether prepared by the redistribution method often has problems such as bimodal distribution of product molecular weight, catalyst residues in the polymer, and difficulty in controlling the molecular structure of the polymer; and the product obtained has high molecular residues, which makes the compatibility of polyphenyl ether with the application system poor when applied downstream.

[0005] However, the method of preparing low molecular weight polyphenyl ether by redistribution method has the above-mentioned defects, and the method of preparing low molecular weight polyphenyl ether by oxidative copolymerization is more commonly used at present. But the existing technology of oxidative copolymerization still has many defects: the product molecular weight distribution is wide, and the size is uneven; the material is difficult to form when the molecular weight is too low, and the processability is poor when the molecular weight is too large; the copper ion residue is high, which seriously affects the dielectric properties of the terminal application; the separation efficiency is low, which affects the product yield and increases the cost of post-processing; most importantly, if the molecular weight is too large, the compatibility with other substrates is poor when used in downstream applications, resulting in layering and foaming of the final product, affecting user experience. For example, in patent CN115626981A, a method for preparing low molecular weight polyphenyl ether by oxidative copolymerization is mentioned, specifically a new polyarylene ether resin and its preparation method. The product number average molecular weight of the polyarylene ether resin prepared in this method is 1000-4000; in the paper "Synthesis of Low Molecular Weight Double-Ended Hydroxyl Polyphenyl Ether" published in "Plastics Industry" Vol. 49 No. 1, it is mentioned that 2,6-dimethylphenol and tetramethyl bisphenol A are used as copolymerization monomers, and the synthesis process of low molecular weight double-ended hydroxyl polyphenyl ether is studied by changing the monomer ratio and catalyst addition ratio. However, the above-mentioned patents and documents do not elaborate and discuss the uniformity of product molecular weight distribution, product functionality, and catalyst residue, which have a very important influence on the application of low molecular weight polyphenyl ether products in high-frequency high-speed copper-clad plates, signal transmission stability, and compatibility with other substrates, and will directly affect its application in the field of high-frequency high-speed copper-clad plates.

[0006] The low molecular weight polyphenyl ether product prepared by the existing technology of oxidative copolymerization has the defects of poor uniformity of product molecular weight distribution, high catalyst residue, and low yield, which need to be solved. SUMMARY

[0007] In order to eliminate the above-mentioned defects of low molecular weight polyphenyl ether prepared by the existing technology of oxidative copolymerization and solve the problem of poor end application effect, the present application provides a preparation method and device for low molecular weight double-ended hydroxyl polyphenyl ether.

[0008] To achieve the above-mentioned purposes, the technical scheme adopted by the present application is as follows: The present application relates to a preparation method and device for low molecular weight double-ended hydroxyl polyphenyl ether, characterized by the following specific process: Step 1: gradient polymerization reaction Mix the reaction monomers 2,6-dimethylphenol (DMP for short) and tetramethyl bisphenol A (TMBPA for short) in a gradient polymerization reaction device according to the molar ratio of n DMP :n TMBPA = (4-15):1, start stirring at a stirring rate of (200-1000) rpm, and perform gradient polymerization reaction in the presence of a reaction solvent and a copper-amine catalyst; The reaction solvent is one of toluene, dichlorobenzene, chlorobenzene; The mol amount n of the reaction solvent 反应溶剂 = (30%-80%)*(n DMP + n TMBPA ); The mol amount n of the copper-amine catalyst cu+ = (0.004-0.14)*(n DMP + n TMBPA ); The gradient polymerization reaction is divided into three stages: The first stage: air is introduced at 30-50°C, the air enters the gradient polymerization reaction device through the air inlet pipe, the initial air flow V1 is (0.3-1)*(n DMP + n TMBPA ) mol / h, and the reaction is carried out for 10-150 minutes; The second stage: the temperature is raised to 55-65°C, the air flow V2 is maintained at the initial air flow, i.e. V2=V1, and the reaction is carried out for 10-150 minutes; The third stage: the temperature is raised to 70-80°C, the air flow V3 is reduced to 50-70% of the initial air flow V1, i.e. V3=(50-70%)*V1, and the reaction is carried out until the intrinsic viscosity reaches 0.07-0.14 dl / g, then a terminating agent is added to terminate the reaction, and a reaction mother liquor is obtained; The terminating agent is one of acetic acid, hydrochloric acid, and citric acid; The molar ratio of the terminating agent to the reaction solvent is n 终止剂 :n 反应溶剂 =(0.05%-0.5%):1; Step 2. Fractionated chelation; After the third stage of the gradient polymerization reaction is completed, the reaction mother liquor obtained in step 1 is introduced into a chelation kettle, and a chelating agent nitrilotriacetic acid (abbreviated as NTA) is added, the molar ratio of NTA to copper ions in the copper-amine catalyst is n NTA :n cu+ =(1.0-2.0):1, and the fractionated chelation is carried out at 25-90°C: the first dropwise addition amount of the chelating agent NTA is (30%-70%) of the total amount n NTA , the addition mode is dropwise addition, and stirring is started at the same time, the stirring rate is (200-1000) rpm; after stirring for 1-2 h, the remaining chelating agent is added again, i.e. the second dropwise addition amount of the chelating agent NTA is (70%-30%) of the total amount n NTA ; at the same time of the second dropwise addition of the remaining chelating agent, a demulsifying agent is added dropwise, after the dropwise addition of the demulsifying agent is completed, the stirring is continued for 1-2 h, and then the chelation impurities are removed by separation and removal, and a mother liquor from which the catalyst is removed is obtained; The demulsifier is one of polyether-modified trisiloxane and polyether-modified heptamethyltrisiloxane; The molar ratio of the demulsifier to the reaction solvent is n 破乳剂 :n 反应溶剂 = (0.05%-0.3%):1; Step 3. Concentration and precipitation; a) Concentration; the catalyst-removed mother liquor obtained in step 2 is introduced into a flash tank to be concentrated at normal pressure to a solid content of 35%-75% through flash evaporation, and low-molecular-weight double-end hydroxyl polyphenyl ether crude concentrate is obtained through solid-liquid separation; b) Precipitation; the double-end hydroxyl polyphenyl ether crude concentrate obtained in a) is added to an anti-solvent tank to which an anti-solvent has been added in advance, and low-molecular-weight double-end hydroxyl polyphenyl ether crude is obtained through precipitation at 25°C-40°C and filtration through a filtering device at a stirring speed of (200-1000) rpm; The anti-solvent is one of methanol, ethanol and glycerol; The molar ratio of the anti-solvent to the catalyst-removed mother liquor is n 反溶剂 :n 脱除催化剂的母液 = (3-10):1; Step 4. Screw extrusion devolatilization: The low-molecular-weight double-end hydroxyl polyphenyl ether crude obtained in step 3 is devolatilized by a screw extruder at 120°C-140°C and a vacuum degree of ≤-0.08 MPa to obtain low-molecular-weight double-end hydroxyl polyphenyl ether wet product; Step 5. Drying The low-molecular-weight double-end hydroxyl polyphenyl ether wet product obtained in step 4 is dried by a drying device at 80°C-120°C under nitrogen protection to obtain low-molecular-weight double-end hydroxyl polyphenyl ether product.

[0009] The copper catalyst in the copper-amine catalyst in step 1 is one of cuprous oxide, cuprous chloride and cuprous bromide; The amine catalyst in the copper-amine catalyst in step 1 is one or two of primary monoamine, secondary monoamine, tertiary monoamine, di-n-butylamine, N,N-dimethylbutylamine and N,N-dibutyl ethylenediamine; The primary monoamine includes any one of n-propylamine, isopropylamine, sec-butylamine, tert-butylamine, n-pentylamine, n-hexylamine and cyclohexylamine; The secondary monoamine includes any one of di-n-propylamine, n-propyl n-butylamine, di-n-butylamine, di-tert-butylamine, n-butyl n-pentylamine and di-n-hexylamine; The tertiary monoamine includes any one of triethylamine, tri-n-propylamine, tri-n-butylamine, dimethyl n-butylamine, dimethyl n-pentylamine, diethyl n-butylamine and tricyclohexylamine; A device for preparing low molecular weight double-end hydroxyl polyphenyl ether, comprising a gradient polymerization device, a chelation kettle, a flash tank, a reverse solvent kettle, a filtering device, a screw extruder and a drying device; The chelation kettle, the flash tank, the reverse solvent kettle, the filtering device, the screw extruder and the drying device are general devices in the prior art; The gradient polymerization device comprises a barrel 10, a stirrer 20, an air inlet pipe 30, a flow guide cylinder 40 and a gas distribution device 50. The barrel is the shell of the gradient polymerization device. The stirrer is located in the middle part of the gradient polymerization device and comprises a stirring shaft, a stirring turbine and stirring blades. The air inlet pipe is located at the bottom of the gradient polymerization device. The flow guide cylinder is located in the middle section of the gradient polymerization device and is connected to the barrel, and is used for guiding the reaction materials in the gradient polymerization device, increasing the mass transfer, heat transfer and momentum transfer. The gas distribution device is connected to the air inlet pipe and is used for uniformly distributing the air entering the gradient polymerization device through the air inlet pipe. The gas distribution device is a ring-shaped distribution pipe-turbulator combined gas distribution device 50, which comprises a horizontally arranged ring-shaped distribution pipe 51 and turbulators 53 arranged on the ring-shaped distribution pipe. The ring-shaped distribution pipe is a ring-shaped hollow closed pipe body, and air outlet holes 52 are uniformly distributed along the upper and lower circumferences of the ring-shaped distribution pipe. The air outlet holes 52 are through holes with a hole diameter of 0.1 mm to 5 mm and a hole spacing of 10 mm to 50 mm. The turbulators 53 are curved surface structures similar to a propeller, the intersection line of the turbulators and the ring-shaped distribution pipe is an s-shape, and the turbulators are arranged in groups corresponding to every two air outlet holes. The turbulators are arranged around the air outlet holes, and when the air escapes from the air outlet holes 52, initial bubble groups are formed, and the dispersion paths of the initial bubble groups are optimized by the turbulators, so that the gas phase is dispersed efficiently, the gas-liquid phase reaction interface is increased, and the gas-liquid phase mixing uniformity and reaction efficiency are improved. The gas distribution device can also be a porous metal or ceramic sintered plate, and the porosity of the porous metal or ceramic sintered plate is 30% to 70%. The combination of the stirrer, the flow guide cylinder and the gas distribution device uniformly disperses and distributes the air entering the reactor through the air inlet pipe, greatly improving the reaction efficiency. The reaction process in the reaction device is as follows: air enters the reactor through the air inlet pipe at the bottom of the reactor, is uniformly distributed through the gas distribution device, and forms a large number of fine bubble groups in the reactor, greatly increasing the contact area of the gas-liquid two phases; the bubble groups are uniformly dispersed under the action of the stirrer, eliminating the dispersion dead zone of the gas, so that the gas phase and the liquid phase material in the reactor are fully mixed and reacted, and then the gas-liquid two phases form a circulating flow under the guiding action of the flow guide cylinder, forming a circulating flow from bottom to top between the outer wall of the flow guide cylinder and the inner wall of the cylinder, and then forming a circulating flow from top to bottom between the inner wall of the flow guide cylinder and the stirring shaft, and then the stirring turbine further contacts, mixes, reacts and circulates with the large number of fine bubble groups formed by the gas distribution device; in this process, the residence time of the gas in the reactor is increased, the reaction is more complete, and the reaction efficiency is improved.

[0010] Advantages: The preparation method and device of the low molecular weight double-end hydroxyl polyphenyl ether of the application solve the problems of poor uniformity of molecular weight distribution, high catalyst residue and low yield of the products in the prior art by setting gradient polymerization reaction, segmented chelation and using special devices: (1) In the gradient polymerization reaction step, by setting gradient temperature and different air flow, the polymerization reaction obtains suitable heat in different stages of chain initiation, chain growth and chain termination, so that the polymerization reaction is more complete, the generation of reaction by-products is greatly reduced, the yield is higher, and the product yield is ≥90% (2) In the segmented chelation step, segmented chelation is used, compared with the one-time centralized addition of the chelating agent in the prior art, precise control and maximum efficiency can be realized, the copper ion residual content is greatly reduced, the high applicability of the product in the downstream application is significantly improved, the dielectric performance of the copper-clad plate can be greatly enhanced, the high copper ion residue in the prior art is solved, the copper ion residue in the application is <20 ppm, and can be further precisely controlled to be <8 ppm; (3) The application of the special device of the application, especially the application of the special structure of the gas distribution device, makes the reaction more complete and uniform, so that the product has narrow molecular weight distribution, good uniformity of product quality and good compatibility with downstream applications. Especially, the product has excellent low viscosity characteristics, which can effectively enhance the thermal performance, dielectric performance, mechanical performance, flame retardance and low moisture absorption when applied to target fields such as the electronic packaging industry, solving the technical problem of wide molecular weight distribution of the product in the prior art. The molecular weight of the product in the application can be controlled to be 1000-5000, and can be further precisely controlled to be 2000-3000, the polymer molecular weight distribution index (PDI) is ≤2.35, and can be further precisely controlled to be 1.35-1.6. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 , the process flow diagram of the embodiment of the present application; Figure 2 , the structural schematic diagram of the gradient polymerization reaction device of the embodiment 1, 4, 5, 6, 7 of the present application; Figure 3 , the structural schematic top view of the annular distribution pipe of the embodiment 1, 4, 5, 6, 7 of the present application; Figure 4 , the schematic diagram of the spoiler of the embodiment 1, 4, 5, 6, 7 of the present application; DRAWINGS

[0012] 10. cylinder; 20. agitator; 21. agitating turbine; 22. agitating blade; 30. air inlet pipe; 40. flow guide cylinder; 50. annular distribution pipe-spoiler combined gas distribution device; 51. annular distribution pipe; 52. air outlet hole; 53. spoiler; DETAILED DESCRIPTION

[0013] The content of the present application is explained by specific embodiments as follows: the technical solution adopted by the present application is: The present application relates to a kind of preparation method of low molecular weight double-end hydroxyl polyphenyl ether, it is characterized in that, specific process is as follows: Step 1: gradient polymerization reaction; Reaction monomer 2, 6-dimethylphenol (abbreviation DMP), tetramethyl bisphenol A (abbreviation TMBPA) is mixed in gradient polymerization reaction device according to n DMP :n TMBPA =(4~15):1 Mole ratio, open stirring, stirring rate is (200~1000) rpm, in the presence of reaction solvent and copper-amine catalyst, gradient polymerization reaction is carried out; The reaction solvent is one of toluene, dichlorobenzene and chlorobenzene; The mol amount n 反应溶剂 =(30%~80%)* ( n DMP + n TMBPA ) of the reaction solvent; The mol amount n cu+ =(0.004~0.14)*( n DMP + n TMBPA ) of copper-amine catalyst; The gradient polymerization reaction is divided into three stages: First stage: 30~50℃ under air, air enters gradient polymerization reaction device through air inlet pipe, and the initial flow rate V1 of air is (0.3~1)*( nDMP + n TMBPA mol / h, for 10-150 minutes; Second stage: temperature is raised to 55-65℃, air flow rate V2 is maintained at the initial air flow rate, i.e. V2=V1, for 10-150 minutes; Third stage: temperature is raised to 70-80℃, air flow rate V3 is reduced to 50%-70% of the initial air flow rate V1, i.e. V3=(50%-70%)*V1, until the intrinsic viscosity reaches 0.07-0.14 dl / g, then a terminating agent is added to terminate the reaction, to obtain a reaction mother liquor; The terminating agent is one of acetic acid, hydrochloric acid, and citric acid; The molar ratio of the terminating agent to the reaction solvent is n 终止剂 : n 反应溶剂 = (0.05%-0.5%):1; Step 2. Fractionated chelation; After the third stage of the gradient polymerization reaction is completed, the reaction mother liquor obtained in Step 1 is introduced into a chelation kettle, and a chelating agent, nitrilotriacetic acid (abbreviated as NTA), is added, with the molar ratio of NTA to copper ions in the copper-amine catalyst being n NTA : n cu+ = (1.0-2.0):1, and the fractionated chelation is carried out at 25-90℃: the first dropwise addition amount of the chelating agent NTA is (30%-70%) of the total amount n NTA , and the dropwise addition is carried out while stirring is started, with the stirring rate being (200-1000) rpm; after stirring for 1-2h, the remaining chelating agent is added again, i.e. the second dropwise addition amount of the chelating agent NTA is (70%-30%) of the total amount n NTA ; while the remaining chelating agent is added again, a demulsifying agent is also added dropwise, and after the dropwise addition of the demulsifying agent is completed, stirring is continued for 1-2h, and then separation and removal of chelation impurities are carried out by standing, to obtain a catalyst-removed mother liquor; The demulsifying agent is one of polyether-modified trisiloxanes and polyether-modified heptamethyltrisiloxane; The molar ratio of the demulsifying agent to the reaction solvent is n 破乳剂 : n 反应溶剂 = (0.05%-0.3%):1; Step 3. Concentration and precipitation; a) Concentration: the catalyst-removed mother liquor obtained in Step 2 is introduced into a flash tank, and is concentrated by atmospheric flash evaporation to a solid content of 35%-75%, to obtain a concentrated crude double-end-hydroxyl polyphenyl ether solution through solid-liquid separation; b) precipitation; the concentrated solution of the crude di-hydroxyl terminated polyphenyl ether obtained in a) is added to the anti-solvent tank to which anti-solvent has been added in advance, and the di-hydroxyl terminated polyphenyl ether crude product is obtained by precipitation at 25-40°C with stirring at a speed of (200-1000) rpm and filtration through a filter device; The anti-solvent is one of methanol, ethanol, and glycerol; The molar ratio of the anti-solvent to the mother liquor of the catalyst removal is n 反溶剂 : n 脱除催化剂的母液 =(3-10): 1; Step 4. Screw extrusion devolatilization: The crude di-hydroxyl terminated polyphenyl ether obtained in step 3 is devolatilized by a screw extruder at 120-140°C and a vacuum degree of ≤-0.08 MPa to obtain di-hydroxyl terminated polyphenyl ether wet product; Step 5. Drying The di-hydroxyl terminated polyphenyl ether wet product obtained in step 4 is dried by a drying device at 80-120°C under nitrogen protection to obtain di-hydroxyl terminated polyphenyl ether product.

[0014] The copper catalyst in the copper-amine catalyst in step 1 is one of cuprous oxide, cuprous chloride, and cuprous bromide; The amine catalyst in the copper-amine catalyst in step 1 is one or two of primary monoamine, secondary monoamine, tertiary monoamine, di-n-butylamine, N,N-dimethylbutylamine, and N,N-dibutyl ethylenediamine; The primary monoamine includes any one of n-propylamine, isopropylamine, sec-butylamine, tert-butylamine, n-pentylamine, n-hexylamine, and cyclohexylamine; The secondary monoamine includes any one of di-n-propylamine, n-propyl n-butylamine, di-n-butylamine, di-tert-butylamine, n-butyl n-pentylamine, and di-n-hexylamine; The tertiary monoamine includes any one of triethylamine, tri-n-propylamine, tri-n-butylamine, dimethyl n-butylamine, dimethyl n-pentylamine, diethyl n-butylamine, and tricyclohexylamine; A device for preparing low-molecular-weight di-hydroxyl terminated polyphenyl ether, comprising a gradient polymerization reaction device, a chelation tank, a flash tank, an anti-solvent tank, a filter device, a screw extruder, and a drying device; The chelation tank, the flash tank, the anti-solvent tank, the filter device, the screw extruder, and the drying device are general devices of the prior art; The gradient polymerization reaction device comprises a barrel 10, a stirrer 20, an air inlet pipe 30, a flow guide cylinder 40, and a gas distribution device 50; The barrel is the outer shell of the gradient polymerization reaction device; The stirrer is located in the middle part of the gradient polymerization reaction device and comprises a stirring shaft, a stirring turbine, and stirring blades; The air inlet pipe is located at the bottom of the gradient polymerization device. The draft tube is located in the middle section of the interior of the gradient polymerization device and is connected with the cylinder body, and is used for guiding the reaction materials in the interior of the gradient polymerization device, increasing the mass transfer, heat transfer and momentum transfer. The gas distribution device is connected with the air inlet pipe, and is used for uniformly distributing the air entering the gradient polymerization device through the air inlet pipe. The gas distribution device is a ring-shaped distribution pipe-turbulator combined gas distribution device 50, which comprises a horizontally arranged ring-shaped distribution pipe 51, air outlet holes 52 and turbulators 53. The air outlet holes 52 are through holes uniformly distributed along the upper and lower periphery of the ring-shaped distribution pipe, and the hole diameter is 0.1-5 mm and the hole spacing is 10-50 mm. The turbulators 53 are curved surface structures similar to a propeller, the intersection line of the turbulators and the ring-shaped distribution pipe is s-shaped, and the turbulators are arranged in groups corresponding to every two air outlet holes. The turbulators are arranged around the air outlet holes, and when the air escapes through the air outlet holes 52, initial micro-bubble groups are formed, and the dispersion path and behavior of the initial bubble groups are optimized by the turbulators, the dispersion dead zone of the bubbles is eliminated, the gas is dispersed efficiently, the gas-liquid phase reaction interface is increased, and the gas-liquid mixing uniformity and reaction efficiency are improved. The gas distribution device can also be a porous metal or ceramic sintered plate, and the porosity of the porous metal or ceramic sintered plate is 30%-70%. The combination of the stirrer, the draft tube and the gas distribution device uniformly disperses and distributes the air entering the reactor through the air inlet pipe, greatly improving the reaction efficiency. The reaction process in the reaction device is as follows: the air enters the reactor through the air inlet pipe at the bottom of the reactor, is uniformly distributed by the gas distribution device, a large number of fine bubbles are formed in the reactor, the contact area of the gas-liquid two phases is greatly increased, the bubbles are uniformly dispersed under the action of the stirrer, are fully mixed and reacted with the liquid phase materials in the reactor, and then form a circulating flow under the guiding action of the draft tube, the circulating flow is formed between the outer wall of the draft tube and the inner wall of the cylinder body, and then the circulating flow is formed between the inner wall of the draft tube and the stirring shaft, the bubbles are further contacted, mixed, reacted and circulated by the stirring turbine and the large number of fine bubbles formed by the gas distribution device; in this process, the residence time of the gas in the reactor is increased, the reaction is more complete, and the reaction efficiency is improved.

[0015] The application realizes precise control of molecular weight by air flow dynamic adjustment and combination of annular distribution pipe-turbolator combined gas distribution device. NTA segmented chelation process and demulsifier are used in combination to reduce copper ion residues; integrated flash evaporation concentration-screw devolatilization-drying separation and purification system is used to improve product yield.

[0016] The internal structure of the reactor in each embodiment and the process parameters in the method for preparing low molecular weight double-end hydroxyl polyphenyl ether are shown in the following table

[0017]

[0018]

[0019] .

Claims

1. A process for the preparation of a low molecular weight, di-hydroxyl terminated polyphenylene ether, characterized in that, The specific process is as follows: Step 1: gradient polymerization reaction; The monomers 2,6-dimethylphenol (DMP) and tetramethylbisphenol A (TMBPA) are reacted in a gradient polymerization apparatus at an inclination of n. DMP :n TMBPA Mix the components in a molar ratio of (4-15):1, start stirring, and carry out gradient polymerization in the presence of the reaction solvent and copper-amine catalyst at a stirring speed of (200-1000) rpm. The reaction solvent is one of toluene, dichlorobenzene, and chlorobenzene; The mol amount n of the reaction solvent 反应溶剂 = (30%~80%) * (n DMP + n TMBPA ) The mol amount n of the copper-amine catalyst cu+ = (0.004-0.14) * (n DMP + n TMBPA ) The gradient polymerization reaction is divided into three stages: The first stage: air is introduced into the gradient polymerization device through the air inlet pipe at 30-50°C, the initial flow rate V1 of the air is (0.3-1)*(n DMP + n TMBPA ) mol / h, and the reaction is carried out for 10-150 minutes. The second stage: air is introduced into the gradient polymerization device through the air inlet pipe at 30-50°C, the flow rate V2 of the air is (0.3-1)*(n DMP + n TMBPA ) mol / h, and the reaction is carried out for 10- The second stage: the temperature is raised to 55-65℃, the air flow V2 is maintained at the initial air flow, i.e. V2=V1, and the reaction is carried out for 10-150 minutes; The third stage: the temperature is raised to 70-80℃, the air flow V3 is reduced to 50-70% of the initial air flow V1, i.e. V3=(50-70%) *V1, and the reaction is terminated when the intrinsic viscosity reaches 0.07-0.14 dl / g, obtaining the reaction mother liquor; Step 2. Subsection chelation; After the third stage of the gradient polymerization reaction is completed, the reaction mother liquor obtained in step 1 is introduced into a chelation kettle, and a chelating agent nitrilotriacetic acid (abbreviated as NTA) is added, the molar ratio of NTA to copper ions in the copper-amine catalyst is n NTA :n cu+ = (1.0-2.0):1, and the chelation is carried out in stages at 25-90°C: the first dropwise addition amount of the chelating agent NTA is (30%-70%) of the total amount n NTA , the addition mode is dropwise addition, and stirring is started at the same time, the stirring rate is (200-1000) rpm; after stirring for 1-2 h, the remaining chelating agent is added again, that is, the second dropwise addition amount of the chelating agent NTA is (70%-30%) of the total amount n NTA ; while the remaining chelating agent is added again, a demulsifier is added dropwise at the same time, after the dropwise addition of the demulsifier is completed, stirring is continued for 1-2 h, and then standing, separation and removal of chelating impurities are carried out to obtain a mother liquor from which the catalyst is removed; The demulsifier is one of polyether-modified trisiloxane and polyether-modified heptamethyltrisiloxane; The molar ratio of the demulsifier to the reaction solvent is n 破乳剂 :n 反应溶剂 = (0.05% to 0.3%): 1; Step 3. Concentration and precipitation; a) Concentration: the catalyst-removed mother liquor obtained in step 2 is introduced into a flash tank for atmospheric flash concentration to a solid content of 35-75%, and a double-end hydroxyl polyphenyl ether concentrate is obtained by solid-liquid separation; b) Precipitation: the double-end hydroxyl polyphenyl ether concentrate obtained in a) is added to an anti-solvent kettle to which an anti-solvent has been added in advance, and after stirring at a speed of (200-1000) rpm at 25-40℃, a double-end hydroxyl polyphenyl ether crude product is obtained after filtration by a filtering device; The anti-solvent is one of methanol, ethanol, and glycerol; The molar ratio of the anti-solvent to the mother liquor of the catalyst removal is n 反溶剂 : n 脱除催化剂的母液 =(3-10): 1; Step 4. Screw extrusion devolatilization: The double-end hydroxyl polyphenyl ether crude product obtained in step 3 is devolatilized by a screw extruder at 120-140℃ and a vacuum degree of ≤-0.08 MPa, obtaining a double-end hydroxyl polyphenyl ether wet product; Step 5. Drying The double-end hydroxyl polyphenyl ether wet product obtained in step 4 is dried by a drying device at 80-120℃ under nitrogen protection, obtaining a low-molecular-weight double-end hydroxyl polyphenyl ether product.

2. A method for preparing a low-molecular-weight double-end hydroxyl polyphenyl ether according to claim 1, characterized in that, The copper catalyst in the copper-amine catalyst in step 1 is one of cuprous oxide, cuprous chloride, and cuprous bromide; The amine catalyst in the copper-amine catalyst in step 1 is one or two of primary monoamine, secondary monoamine, tertiary monoamine, di-n-butylamine, N,N-dimethylbutylamine, and N,N-dibutyl ethylenediamine; The primary monoamine includes any one of n-propylamine, isopropylamine, sec-butylamine, tert-butylamine, n-pentylamine, n-hexylamine, and cyclohexylamine; The secondary monoamine includes any one of di-n-propylamine, n-propyl n-butylamine, di-n-butylamine, di-tert-butylamine, n-butyl n-pentylamine, and di-n-hexylamine; The tertiary monoamine includes any one of triethylamine, tri-n-propylamine, tri-n-butylamine, dimethyl n-butylamine, dimethyl n-pentylamine, diethyl n-butylamine, and tricyclohexylamine.

3. A process for the production of a low molecular weight, both terminally hydroxylated polyphenylene ether as claimed in claim 1 or 2, characterized in that, In the third stage of step 1, the reaction is terminated by adding a terminating agent; The terminating agent is one of acetic acid, hydrochloric acid, and citric acid; The molar ratio of the terminator to the reaction solvent is n 终止剂 :n 反应溶剂 = (0.05%~0.5%):

1.

4. An apparatus for producing low molecular weight, dihydroxyl-terminated polyphenylene ether by the process of claim 1 or 2, characterized by The device includes a gradient polymerization reaction device, a chelation kettle, a flash tank, an anti-solvent kettle, a filtering device, a screw extruder, and a drying device; The chelation kettle, the flash tank, the anti-solvent kettle, the filtering device, the screw extruder, and the drying device are general devices in the prior art. The gradient polymerization device comprises a cylinder, a stirrer, an air inlet pipe, a flow guide cylinder and a gas distribution device. The cylinder is the shell of the gradient polymerization device. The stirrer is located in the middle part of the gradient polymerization device and comprises a stirring shaft, a stirring turbine and stirring blades. The air inlet pipe is located at the bottom of the gradient polymerization device. The flow guide cylinder is located in the middle section of the gradient polymerization device and is connected with the cylinder. The gas distribution device is connected with the air inlet pipe. The gas distribution device is a ring-shaped distribution pipe-turbulator combined gas distribution device, which comprises a horizontally arranged ring-shaped distribution pipe and turbulators arranged on the ring-shaped distribution pipe. The ring-shaped distribution pipe is a ring-shaped hollow closed pipe body, and air outlet holes are uniformly distributed along the upper and lower peripheries of the ring-shaped distribution pipe. The air outlet holes are through holes with a diameter of 0.1 mm to 5 mm and a hole spacing of 10 mm to 50 mm. The turbulators are curved surface structures similar to a propeller, and the intersection line of the turbulators and the ring-shaped distribution pipe is an s-shaped line.

5. An apparatus for producing low molecular weight, dihydroxyl terminated polyphenylene ether by the process of claim 3, characterized by, The turbulators are arranged around the air outlet holes and are arranged in groups corresponding to every two air outlet holes. The gradient polymerization device, a chelation kettle, a flash tank, a reverse solvent kettle, a filtering device, a screw extruder and a drying device are provided. The chelation kettle, the flash tank, the reverse solvent kettle, the filtering device, the screw extruder and the drying device are general devices in the prior art. The gradient polymerization device comprises a cylinder, a stirrer, an air inlet pipe, a flow guide cylinder and a gas distribution device. The cylinder is the shell of the gradient polymerization device. The stirrer is located in the middle part of the gradient polymerization device and comprises a stirring shaft, a stirring turbine and stirring blades. The air inlet pipe is located at the bottom of the gradient polymerization device. The flow guide cylinder is located in the middle section of the gradient polymerization device and is connected with the cylinder. The gas distribution device is connected with the air inlet pipe. The gas distribution device is a ring-shaped distribution pipe-turbulator combined gas distribution device, which comprises a horizontally arranged ring-shaped distribution pipe and turbulators arranged on the ring-shaped distribution pipe. The ring-shaped distribution pipe is a ring-shaped hollow closed pipe body, and air outlet holes are uniformly distributed along the upper and lower peripheries of the ring-shaped distribution pipe. The air outlet holes are through holes with a diameter of 0.1 mm to 5 mm and a hole spacing of 10 mm to 50 mm.

6. An apparatus for producing low molecular weight, dihydroxyl terminated polyphenylene ether as claimed in claim 4, wherein, The turbulators are curved surface structures similar to a propeller, and the intersection line of the turbulators and the ring-shaped distribution pipe is an s-shaped line.

7. A device for producing low molecular weight, dihydroxyl-terminated polyphenylene ether according to claim 5, wherein The turbulators are arranged around the air outlet holes and are arranged in groups corresponding to every two air outlet holes.

8. An apparatus for producing low molecular weight, dihydroxyl terminated polyphenylene ether as claimed in claim 4, wherein, The gas distribution device is a porous metal or ceramic sintered plate.

9. An apparatus for producing low molecular weight, dihydroxyl terminated polyphenylene ether as claimed in claim 5, wherein, The gas distribution device is a porous metal or ceramic sintered plate. The porosity of the porous metal or ceramic sintered plate is 30% to 70%. The porosity of the porous metal or ceramic sintered plate is 30% to 70%.

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