An environmentally friendly production method for continuously producing brominated polycarbonate

Abstract

The present application provides a kind of continuous production brominated polycarbonate environmentally friendly production method, it is related to brominated polycarbonate field.The continuous production brominated polycarbonate environmentally friendly production method, including following steps: first photocatalytic decomposition, second photocatalytic decomposition, microchannel polymerization, purification, post-processing.The continuous production brominated polycarbonate environmentally friendly production method of the present application, can effectively overcome the existing brominated polycarbonate industrial production method exists in the problems of high catalyst cost, catalyst short service life, easy to produce by-product, low reaction efficiency, process flow is complicated, poor safety;And realize the high precision control of the molecular weight, molecular weight distribution and particle size distribution of the prepared brominated polycarbonate.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of brominated polycarbonate, in particular to an environmentally friendly production method for continuously producing brominated polycarbonate. BACKGROUND

[0002] Brominated polycarbonate is a high-efficiency environmentally friendly bromine-based flame retardant, which contains brominated bisphenol A carbonate structure (such as tetrabromobisphenol A copolymer) in the molecular chain. This structure endows it with excellent flame retardant properties. Bromine element can decompose to produce free radicals at high temperature, thereby blocking the combustion chain reaction and achieving flame retardant effect. Compared with chlorinated products, brominated polycarbonate has higher heat resistance, with a softening point of 350-370℃, and higher flame retardant efficiency. Brominated polycarbonate is mainly used in the flame retardant treatment of thermoplastic plastics with low transparency requirements, such as polyester materials, engineering plastics, electronic and electrical materials, etc.

[0003] Chinese patent CN118056857A discloses a method for continuously producing polycarbonate and polycarbonate. First, an alkaline aqueous solution containing bisphenol sodium salt and an organic solution containing phosgene are subjected to interfacial polymerization reaction to obtain a photochemical reaction liquid containing polycarbonate oligomers. The molecular chain of the polycarbonate oligomers can ionize at the interface of the alkaline photochemical reaction liquid to obtain a polymer chain containing phenolic oxygen anions, which then adsorb on the surface of water droplets to form a macromolecular surfactant to stabilize the emulsion. Subsequently, the above-mentioned photochemical reaction liquid containing polycarbonate oligomers is placed in a three-stage dispersion device for three-stage dispersion, and an end-capping agent is added to the photochemical reaction liquid before each stage of dispersion to control the molecular weight of the polymer, obtaining a water-in-oil dispersion emulsion. In this process, the end-capping agent is added three times, and the end-capping effect of the end-capping agent is improved by three times of dispersion. Finally, the dispersion emulsion obtained by three-stage dispersion is subjected to polycondensation reaction to obtain polycarbonate with a certain molecular weight. Although this patent can produce polycarbonate with low hydroxyl end group content and good yellowing resistance, the reaction efficiency is low, and the multiple batch addition of the end-capping agent can greatly increase the risk of phosgene leakage. At the same time, the molecular weight of the polycarbonate product obtained is single and cannot be adjusted, and the process flexibility is low.

[0004] Chinese patent CN103848983B discloses a method for synthesizing brominated polycarbonate. The method uses a homogeneous method to produce brominated polycarbonate, which reduces mass transfer resistance and reduces reactant consumption. At the same time, a self-made composite catalyst is used for reaction catalysis during the reaction process. The by-product hydrochloric acid generated during the reaction process is extracted under micro-negative pressure and absorbed by water to generate hydrochloric acid. Specifically, the solvent toluene, raw material triphosgene and composite catalyst are mixed into a transparent solution, then the toluene solution of tetrabromobisphenol A is added dropwise at a temperature of 50-70℃, the reaction time is controlled for 3-6h, and then the brominated polycarbonate is prepared after end-capping. However, the risk of phosgene leakage is high during the preparation process, and the molecular weight of the prepared brominated polycarbonate is single, which cannot effectively adjust the molecular weight of the product.

[0005] Chinese patent CN116425965B discloses a flame-retardant copolymerized polycarbonate and a preparation method thereof. The first liquid is mixed uniformly with a sodium salt solution of bisphenol A, and then the phosgene solution is simultaneously introduced into a two-stage tubular reactor to react for 45-300s to obtain a second liquid. Then, in a three-stage tubular reactor, the low molecular weight copolymerized polycarbonate is subjected to end-capping reaction under the action of an end-capping agent. Although this patent can realize continuous production of flame-retardant copolymerized polycarbonate, the halogen content of the prepared flame-retardant copolymerized polycarbonate can only reach 34.52% at most, and its reaction safety, environmental protection and product molecular weight controllability need to be further improved.

[0006] Further, the traditional industrial preparation method of brominated polycarbonate is as follows: (1) dissolving the catalyst 4-dimethylaminopyridine in water to obtain a catalyst solution for standby; (2) adding tetrabromobisphenol A, an organic solvent, triphosgene and water in a reaction container, and stirring uniformly; (3) adding the catalyst solution into the reaction container, and stirring uniformly; (4) dissolving sodium hydroxide and monohydric phenol in water to obtain a mixed solution, then slowly dropping the mixed solution into the reaction container at a predetermined reaction temperature, and stirring to obtain a reaction liquid; (5) washing the reaction liquid with alkali, and then standing and separating the layers to separate the organic layer; (6) washing the organic layer with acid, and then standing and separating the layers to separate the organic layer; (7) washing the organic layer with deionized water, and then standing and separating the layers to separate the organic layer; (8) evaporating and drying the organic layer to obtain brominated polycarbonate. The method has problems of high catalyst cost (about 200,000 yuan / ton), short catalyst life, easy production of by-products, low reaction efficiency, complicated process flow and poor safety; at the same time, due to the reaction of phosgene with the end-capping agent to form small molecular substances during the preparation process, the molecular weight, molecular weight distribution and particle size distribution of the brominated polycarbonate cannot be controlled with high precision. SUMMARY

[0007] In order to solve the technical problems in the prior art, the present application provides an environmentally-friendly production method for continuously producing brominated polycarbonate, which can effectively overcome the problems of high catalyst cost, short catalyst service life, easy production of by-products, low reaction efficiency, complicated process flow and poor safety in the existing industrial production method of brominated polycarbonate, and realize high-precision control of the molecular weight, molecular weight distribution and particle size distribution of the prepared brominated polycarbonate.

[0008] In order to solve the above technical problems, the technical solutions adopted by the present application are as follows:

[0009] An environmentally-friendly production method for continuously producing brominated polycarbonate, comprising the following steps: first photocatalytic decomposition, second photocatalytic decomposition, micro-channel polymerization reaction, purification, post-treatment;

[0010] In the first photocatalytic decomposition, the solution of triphosgene is continuously introduced into the reaction pipeline of the first photocatalytic reactor, and the first photocatalytic decomposition is continuously carried out in the presence of the first catalyst under light conditions, so as to continuously obtain the first photocatalytic decomposition product.

[0011] In the second photocatalytic decomposition, the solution of aminocarbonyl compound is continuously introduced into the reaction pipeline of the second photocatalytic reactor, and the second photocatalytic decomposition is continuously carried out in the presence of the second catalyst under light conditions, so as to continuously obtain the second photocatalytic decomposition product.

[0012] In the micro-channel polymerization reaction, the first photocatalytic decomposition product and the second photocatalytic decomposition product are pre-mixed by a static mixer, then continuously introduced into the micro-mixer for mixing, and used as the first material; after the first material and the second material are mixed into a mixed solution, the mixed solution is continuously introduced into the first micro-reactor for polymerization reaction, so as to continuously obtain the polymerization reaction product.

[0013] The second material is a mixed solution of tetrabromobisphenol A.

[0014] The polymerization reaction product is purified and post-treated to obtain the brominated polycarbonate.

[0015] Further, in the purification, the polymerization reaction product and the washing liquid are simultaneously introduced into the second micro-reactor, and after washing and purification, the washing and purification product is continuously obtained.

[0016] In the post-treatment, the washing and purification product is added to water, and after distillation and desolventization, the solid is collected and dried to obtain the brominated polycarbonate.

[0017] Further, in the first photocatalytic decomposition, the feeding rate of the triphosgene solution introduced into the first photocatalytic reactor is 3-20 mL / min, the wavelength of light is 100-280 nm, the first photocatalytic decomposition temperature is controlled to be 15-36℃, and the material residence time is 3-16 min.

[0018] The triphosgene solution is composed of triphosgene and a first solvent, the concentration of triphosgene is 0.5-25 mol / L; the first solvent is at least one of toluene, chloroform, dihalomethane, dihaloethane, carbon tetrahalide, chlorinated benzene, dichlorobenzene.

[0019] Preferably, in the first photocatalytic decomposition, the first catalyst is at least one of titanium dioxide, nitrogen-doped titanium dioxide, zinc oxide, titanium nitride, carbon nitride, halogenated rare earth compound, tungstate compound;

[0020] The concentration of the first catalyst is 0.3-0.5 mg / mL.

[0021] Further, in the second photocatalytic decomposition, the feeding rate of the aminocarbonyl compound solution into the second photocatalytic reactor is 0.5-10 mL / min, the wavelength of light is 340-387 nm, the temperature of the second photocatalytic decomposition is controlled to be 30-50℃, and the residence time of the material is 1-12 min;

[0022] The aminocarbonyl compound solution is composed of an aminocarbonyl compound and a second solvent, the concentration of the aminocarbonyl compound is 1-25 mol / L; the aminocarbonyl compound is one of amino acid, amide, urea; the second solvent is at least one of deionized water, methanol, ethanol.

[0023] Preferably, in the second photocatalytic decomposition, the second catalyst is at least one of titanium dioxide, noble metal catalyst, transition metal catalyst, zinc oxide;

[0024] The concentration of the second catalyst is 1-2.5 mg / mL.

[0025] Preferably, in the microchannel polymerization reaction, the feeding rate of the mixed solution into the first microreactor is 5-20 g / min; the polymerization reaction temperature is controlled to be 30-40℃, and the residence time of the material is 1-16 min.

[0026] Preferably, the mass ratio of the first photocatalytic decomposition product and the second photocatalytic decomposition product in the first material is 3-25:1;

[0027] The second material is composed of tetrabromobisphenol A, basic compound, capping agent, deionized water and organic solvent;

[0028] The mass ratio of the first material to the second material in the mixed solution is 753-971:1578-1638.

[0029] Preferably, the basic compound is one of sodium hydroxide, potassium hydroxide, aluminum hydroxide, ammonia water, potassium methoxide;

[0030] the end-capping agent is phenol;

[0031] the organic solvent is carbon tetrachloride or toluene;

[0032] Preferably, the weight ratio of tetrabromobisphenol A, basic compound, end-capping agent, deionized water and organic solvent in the second material is 333:65:20-80:580:580.

[0033] Preferably, in the purification, the washing purification temperature is controlled to be 20-25℃, and the material residence time is 1-10 min.

[0034] the washing liquid is at least one of deionized water, methanol and acetone;

[0035] the volume ratio of the washing liquid to the polymerization product is 1:1-5.

[0036] Compared with the prior art, the present application has the following advantages:

[0037] (1) The continuous production method of brominated polycarbonate of the present application continuously performs first photocatalytic decomposition on triphosgene to obtain a first photocatalytic decomposition product, and performs second photocatalytic decomposition on an aminocarbonyl compound to obtain a second photocatalytic decomposition product. The first photocatalytic decomposition product and the second photocatalytic decomposition product are mixed as a first material, which is mixed with a second material (a tetrabromobisphenol A mixed solution) to perform a micro-channel polymerization reaction, and then purified and post-treated to obtain brominated polycarbonate. The various technical means cooperate with each other and synergize to effectively overcome the problems of high catalyst cost, short catalyst service life, easy production of by-products, low reaction efficiency, complicated process flow and poor safety in the existing industrial production method of brominated polycarbonate. The molecular weight, molecular weight distribution and particle size distribution of the prepared brominated polycarbonate can be controlled with high precision.

[0038] (2) The continuous production method of brominated polycarbonate of the present application effectively solves the problems of high catalyst cost and short service life, cooperates with the specific process method of the present application, effectively improves the durability of the catalyst used, reduces the catalyst replacement frequency (about once every 14 days of continuous production), and improves the production efficiency. At the same time, the price of the catalyst used is much lower than that of the existing catalyst, which further reduces the production cost.

[0039] (3) The continuous production method of brominated polycarbonate of the present application can effectively reduce and remove by-products, improve the control precision of the molecular weight and particle size of brominated polycarbonate, and improve the performance of brominated polycarbonate products by using a continuous micro-channel device for reaction and purification.

[0040] (4) The continuous production method for brominated polycarbonate of the present application has a simple process flow and is easy to operate, which can greatly shorten the reaction time, improve the production efficiency, reduce the production cost, and improve the safety during the production process.

[0041] (5) The continuous production method for brominated polycarbonate of the present application effectively solves the problem of low control precision of molecular weight and particle size in the preparation of existing brominated polycarbonate, realizes the set production of the molecular weight of brominated polycarbonate product, and the molecular weight distribution (Mz / Mw) of the prepared brominated polycarbonate is within the range of 1-1.2, which can further expand the application field of brominated polycarbonate product.

[0042] (6) The continuous production method for brominated polycarbonate of the present application can effectively solve the problems of material leakage and odor in the intermittent preparation process of existing brominated polycarbonate, can ensure the closed production process, effectively improve the safety, and ensure the continuous preparation of brominated polycarbonate.

[0043] (7) The continuous production method for brominated polycarbonate of the present application synchronously uses photocatalytic decomposition of triphosgene and photocatalytic decomposition of aminocarbonyl compound, and decomposes in a safe, environmentally friendly, efficient and low-energy-consumption manner under a photocatalytic environment, effectively prevents phosgene leakage, reduces the unit reaction phosgene and content, and increases the service life of the catalyst; at the same time, the static mixer is used for premixing, which further reduces the reaction time and improves the reaction efficiency; further, the microreactor is used for continuous polymerization reaction, which reduces the reaction equivalent, improves the reaction rate, and cooperates with the addition amount of the end-capping agent and the related process parameters of the polymerization reaction to accurately control the molecular weight and particle size distribution of the brominated polycarbonate; and the microreactor is used for washing, which further improves the production rate and ensures the quality of the brominated polycarbonate product. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 Gel permeation chromatogram of the brominated polycarbonate prepared in Example 4.

[0045] Figure 2 Gel permeation chromatogram of the brominated polycarbonate prepared in Example 9.

[0046] Figure 3 Particle size distribution graph of the brominated polycarbonate prepared in Examples 1-9. In the graph, Sample One to Sample Nine correspond to the brominated polycarbonate prepared in Examples 1 to 9, respectively. DETAILED DESCRIPTION

[0047] In order to have a clearer understanding of the technical features, objectives and effects of the present application, the specific embodiments of the present application will now be described. It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used in the present application have the same meaning as commonly understood by those of ordinary skill in the art to which the present application belongs.

[0048] It should be noted that the terms used herein are only intended to describe specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, "first", "second", and the like are used to distinguish similar objects, and are not intended to describe a particular order or sequence, and it should also be understood that when the terms "comprise" and / or "include" are used in the present description, the presence of a feature, step, operation, device, component and / or combination thereof is indicated.

[0049] The present application provides an environmentally friendly production method for continuously producing brominated polycarbonate, comprising the following steps: first photocatalytic decomposition, second photocatalytic decomposition, micro-channel polymerization reaction, purification, post-treatment.

[0050] The method for the first photocatalytic decomposition (i.e. continuous decomposition of triphosgene) is as follows: a certain amount of triphosgene and a first solvent are weighed and added to a blue cap bottle, which is sealed and shaken to obtain a triphosgene solution with a concentration of 0.5-25 mol / L, and then placed in a glove box; the triphosgene solution feed pump is turned on, and the triphosgene solution is continuously fed into the reaction pipeline of the first photocatalytic reactor at a feed rate of 3-20 mL / min; in the presence of a first catalyst and under light, the first photocatalytic decomposition temperature is controlled at 15-36℃, and the residence time of the triphosgene solution in the reaction pipeline is 3-16 min (preferably 5-8 min), and the photocatalytic decomposition of triphosgene is continuously carried out; the obtained first photocatalytic decomposition product is continuously introduced into the micro-mixer through a static mixer.

[0051] In the first photocatalytic decomposition, in order to initiate the free radical reaction of photocatalytic decomposition of triphosgene, the wavelength of the light source is 100-280 nm, preferably 200-280 nm (i.e. ultraviolet C band).

[0052] The first solvent is at least one of the following: toluene, chloroform, dihalomethane, dihaloethane, carbon tetrahalide, chlorinated benzene, dichlorobenzene; preferably toluene and carbon tetrachloride, and the weight ratio of toluene to carbon tetrachloride is 0.5-2:1.

[0053] The first catalyst is at least one of the following: titanium dioxide, nitrogen-doped titanium dioxide, zinc oxide, titanium nitride, carbon nitride, halogenated rare earth compound, tungstate compound; the first catalyst is preferably at least one of the following: titanium dioxide, zinc oxide, titanium nitride, cerium chloride.

[0054] The concentration of the first catalyst is 0.01-100 mg / mL, preferably 0.3-0.5 mg / mL.

[0055] The method of the second photocatalytic decomposition (i.e. continuous decomposition of the aminocarbonyl compound) is as follows: a certain amount of the aminocarbonyl compound and the second solvent are weighed and added to a blue cap bottle, which is sealed and shaken to obtain an aminocarbonyl compound solution with a concentration of 1-25 mol / L; the aminocarbonyl compound solution feed pump is turned on, and the aminocarbonyl compound solution is continuously fed into the reaction pipeline of the second photocatalytic reactor at a feed rate of 0.5-10 mL / min; in the presence of the second catalyst, the second photocatalytic decomposition temperature is controlled at 30-50°C, the residence time of the aminocarbonyl compound solution in the reaction pipeline is 1-12 min (preferably 5-8 min), and the photocatalytic decomposition of the aminocarbonyl compound is continuously carried out; the obtained second photocatalytic decomposition product is continuously introduced into the micro-mixer through the static mixer.

[0056] In the second photocatalytic decomposition, in order to promote the decomposition of the aminocarbonyl compound, the chemical bonds in the aminocarbonyl compound molecule are broken by providing sufficient energy through ultraviolet light, and the wavelength of the light source is 340-387 nm.

[0057] The aminocarbonyl compound is one of the following: an amino acid, an amide, and urea; preferably urea.

[0058] The second solvent is at least one of the following: deionized water, methanol, and ethanol; preferably deionized water.

[0059] The second catalyst is at least one of the following: titanium dioxide, a noble metal (iridium Ir or ruthenium Ru) catalyst, a transition metal (cobalt, nickel or rhodium) catalyst, and zinc oxide; preferably a transition metal catalyst; more preferably dicobalt octacarbonyl.

[0060] The concentration of the second catalyst is 0.01-100 mg / mL, preferably 1-2.5 mg / mL.

[0061] The method of the micro-channel polymerization reaction is as follows: the first photocatalytic decomposition product and the second photocatalytic decomposition product are pre-mixed by the static mixer and continuously introduced into the micro-mixer for mixing, serving as the first material into the mixing coil; at the same time, the tetrabromobisphenol A mixed solution feed pump is turned on, serving as the second material into the mixing coil; after the first material and the second material are mixed into a mixed solution in the mixing coil, the mixed solution is continuously fed into the first micro-reactor and its reaction coil at a feed rate of 5-20 g / min, the reaction temperature is controlled at 30-40°C (preferably 35-39°C), and the residence time of the material is 1-16 min (preferably 1-5 min), and the polymerization reaction is carried out to continuously obtain the polymerization product.

[0062] The mass ratio of the first photocatalytic decomposition product and the second photocatalytic decomposition product in the first material in the microchannel polymerization reaction is 3-25:1, preferably 6-8:1.

[0063] The second material (a mixed solution of tetrabromobisphenol A) is a mixture of tetrabromobisphenol A, an alkaline compound, an end-capping agent phenol, deionized water, and an organic solvent. The alkaline compound is one of sodium hydroxide, potassium hydroxide, aluminum hydroxide, ammonia, and potassium methoxide; preferably sodium hydroxide. The organic solvent is carbon tetrachloride or toluene; preferably toluene.

[0064] In the mixed solution, the mass ratio of the first material to the second material is 753-971:1578-1638.

[0065] The weight ratio of tetrabromobisphenol A, an alkaline compound, an end-capping agent phenol, deionized water, and an organic solvent in the second material is 333:65:20-80:580:580.

[0066] The purification method is to continuously feed the polymerization product and the washing liquid into the second microreactor, control the washing and purification temperature to be 20-25°C, and control the residence time of the material to be 1-10 min (preferably 3-5 min), and continuously obtain the washing and purification product after washing and purification.

[0067] In the purification, the washing liquid is at least one of deionized water, methanol, and acetone.

[0068] The volume ratio of the washing liquid to the polymerization product is 1:1-5 (preferably 1:3).

[0069] The post-treatment method is to add the washing and purification product to water, heat to boiling, and then distill and precipitate the product after heat preservation, and then filter and dry to obtain brominated polycarbonate.

[0070] The application will be further described below in combination with some specific examples.

[0071] The main equipment used in each example is as follows:

[0072] Pump 1-constant flow pump (phosgene solution feeding pump), produced by Shanghai Tongtian Biotechnology Co., Ltd., made of stainless steel, model TBP5002S, flow range 0.1-50 mL / min. The first photocatalytic reactor (phosgene) has a size of 220x112.7x3 mm, and the light source wavelength is 280 nm (adjustable); the first solvent is used to calibrate the flow of the phosgene solution feeding pump (pump 1).

[0073] Pump 2-Constant flow pump (aminocarbonyl compound solution feed pump), manufacturer Shanghai Tongtian Biotechnology Co., Ltd., material stainless steel, model TBP1002S, flow range 0.1-10 mL / min. The second photocatalytic reactor (aminocarbonyl compound) has a size of 210x180x3mm and a light source wavelength of 365nm (adjustable); the second solvent is used to calibrate the flow of the aminocarbonyl compound solution feed pump (pump 2).

[0074] Pump 3-Constant flow pump (tetrabromobisphenol A mixed solution feed pump), manufacturer Shanghai Tongtian Biotechnology Co., Ltd., material stainless steel, model TBP5002S, flow range 0.1-50 mL / min. The micro-mixer uses a sieve plate (1, 0.5mm sieve hole) and a layer of raw material belt between the four fluorine sheets for sealing; the reaction coil is a 1 / 8 four fluorine tube with an outer diameter x inner diameter = 3.17x1.58mm and a length of 17.5m; deionized water is used to calibrate the flow of the tetrabromobisphenol A mixed solution feed pump (pump 3).

[0075] The main raw materials used in each embodiment are as follows:

[0076] Triphosgene, manufacturer Aladdin Reagent (Shanghai) Co., Ltd., purity >99%;

[0077] Urea, manufacturer Aladdin Reagent (Shanghai) Co., Ltd., purity ≥99.5%.

[0078] Toluene is used after drying with molecular sieves.

[0079] Carbon tetrachloride is used after drying with molecular sieves.

[0080] Example 1

[0081] This embodiment provides an environmentally friendly production method for continuously producing brominated polycarbonate, specifically:

[0082] 1. First photocatalytic decomposition

[0083] 75g of triphosgene and a first solvent (400g of toluene, 200g of carbon tetrachloride) were weighed and added to a blue cap bottle, sealed and shaken to obtain a triphosgene solution, which was then placed in a glove box; the triphosgene solution feed pump was turned on, and the triphosgene solution was continuously fed into the reaction pipeline of the first photocatalytic reactor at a feed rate of 5mL / min; in the presence of the first catalyst and under light, the first photocatalytic decomposition temperature was controlled at 23℃, the residence time of the triphosgene solution in the reaction pipeline was 7min, and the photocatalytic decomposition of triphosgene was continuously carried out; the obtained first photocatalytic decomposition product was continuously introduced into the micro-mixer through the static mixer.

[0084] The light source has a wavelength of 280 nm to break the chemical bonds in the amino carbonyl compound molecules.

[0085] The first catalyst is composed of titanium dioxide and zinc oxide, and the mass ratio of titanium dioxide to zinc oxide is 1:1. The concentration of the first catalyst is 0.3 mg / mL.

[0086] 2. Second photocatalytic decomposition

[0087] The amino carbonyl compound (6 g of urea) and the second solvent (100 mL of deionized water) are weighed and added to a blue cap bottle, which is sealed and shaken to obtain a urea solution. The urea solution is continuously fed into the reaction pipeline of the second photocatalytic reactor at a feeding rate of 1 mL / min by opening the amino carbonyl compound solution feeding pump. In the presence of the second catalyst and under light, the second photocatalytic decomposition temperature is controlled at 38°C, and the residence time of the urea solution in the reaction pipeline is 7 min. The urea is continuously photocatalytically decomposed. The obtained second photocatalytic decomposition product is continuously introduced into the micro-mixer through the static mixer.

[0088] The light source has a wavelength of 365 nm to break the chemical bonds in the amino carbonyl compound molecules.

[0089] The second catalyst is octacarbonyldicobalt, and the concentration of the second catalyst is 2 mg / mL.

[0090] 3. Micro-channel polymerization reaction

[0091] The first photocatalytic decomposition product and the second photocatalytic decomposition product are continuously introduced into the micro-mixer through the static mixer for mixing as the first material into the mixing coil. At the same time, the four-brominated bisphenol A mixed solution feeding pump (pump 3) is opened to enter the mixing coil as the second material. The first material and the second material are mixed into a mixed solution in the mixing coil at a temperature of 18°C, and then continuously enter the first micro-reactor and its reaction coil at a feeding rate of 9 g / min. The reaction temperature is controlled at 37°C, and the residence time of the material is 117.58 s. After the polymerization reaction, the polymerization product is continuously obtained.

[0092] The second material (four-brominated bisphenol A mixed solution) is composed of 333 g of four-brominated bisphenol A, 65 g of sodium hydroxide (basic compound), 80 g of end-capping agent phenol, 580 g of deionized water, and 580 g of toluene (organic solvent).

[0093] In the mixed solution, the mass ratio of the first material to the second material is 828:1638.

[0094] 4. Purification

[0095] The polymerization product and deionized water (washing liquid) are continuously fed into the second micro-reactor, the washing purification temperature is controlled at 20°C, the material residence time is 5 min, and after washing purification, the washing purification product is continuously obtained.

[0096] The volume ratio of the washing liquid to the polymerization product is 1:3.

[0097] 5, post-treatment

[0098] The washing purification product is added to water, heated to boiling, and after heat preservation distillation desolventizing, the product is precipitated, filtered and dried to obtain brominated polycarbonate.

[0099] Example 2

[0100] The embodiment provides an environmentally friendly production method for continuously producing brominated polycarbonate, specifically:

[0101] 1, first photocatalytic decomposition

[0102] 75 g of triphosgene and a first solvent (300 g of toluene and 300 g of carbon tetrachloride) are weighed and added to a blue cap bottle, sealed and shaken to obtain a triphosgene solution, and then placed in a glove box; a triphosgene solution feeding pump is started, and the triphosgene solution is continuously fed into the reaction pipeline of the first photocatalytic reactor at a feeding rate of 5 mL / min; in the presence of the first catalyst and under light, the first photocatalytic decomposition temperature is controlled at 18°C, and the residence time of the triphosgene solution in the reaction pipeline is 8 min, and the triphosgene is continuously photocatalytically decomposed; the obtained first photocatalytic decomposition product is continuously introduced into the micro-mixer through the static mixer.

[0103] In order to initiate the free radical reaction of photocatalytic decomposition of triphosgene, the wavelength of the light source is 280 nm.

[0104] The first catalyst is titanium dioxide; the concentration of the first catalyst is 0.4 mg / mL.

[0105] 2, second photocatalytic decomposition

[0106] 6 g of aminocarbonyl compound (urea) and a second solvent (100 mL of deionized water) are weighed and added to a blue cap bottle, sealed and shaken to obtain a urea solution; a urea solution feeding pump is started, and the urea solution is continuously fed into the reaction pipeline of the second photocatalytic reactor at a feeding rate of 1 mL / min; in the presence of the second catalyst and under light, the second photocatalytic decomposition temperature is controlled at 32°C, and the residence time of the urea solution in the reaction pipeline is 8 min, and the urea is continuously photocatalytically decomposed; the obtained second photocatalytic decomposition product is continuously introduced into the micro-mixer through the static mixer.

[0107] Wherein, in order to promote the decomposition of aminocarbonyl compounds, enough energy is provided by ultraviolet light to break the chemical bond in the aminocarbonyl compound molecule, and the light wavelength of the light source is 365 nm.

[0108] The second catalyst is octacarbonyldicobalt; the concentration of the second catalyst is 1.2 mg / mL.

[0109] 3. Microchannel polymerization reaction

[0110] The first photocatalytic decomposition product and the second photocatalytic decomposition product are continuously introduced into the micro-mixer for mixing as the first material into the mixing coil; at the same time, the tetrabromobisphenol A mixed solution feeding pump (pump 3) is started to enter the mixing coil as the second material; the first material and the second material are mixed into a mixed solution in the mixing coil at a temperature of 18℃, and then continuously enter the first micro-reactor and its reaction coil at a feeding rate of 9 g / min, and the reaction temperature is controlled at 37℃, and the material residence time is 117.58 s, and after the polymerization reaction, the polymerization reaction product is continuously obtained.

[0111] Wherein, the second material (tetrabromobisphenol A mixed solution) is composed of 333 g of tetrabromobisphenol A, 65 g of sodium hydroxide (basic compound), 80 g of end-capping agent phenol, 580 g of deionized water, and 580 g of toluene (organic solvent).

[0112] In the mixed solution, the mass ratio of the first material to the second material is 828:1638.

[0113] 4. Purification

[0114] The polymerization reaction product and deionized water (washing liquid) are continuously fed into the second micro-reactor, the washing and purification temperature is controlled at 22℃, and the material residence time is 4 min, and after the washing and purification, the washing and purification product is continuously obtained.

[0115] Wherein, the volume ratio of the washing liquid to the polymerization reaction product is 1:2.5.

[0116] 5. Post-treatment

[0117] The washing and purification product is added to water, heated to boiling, and the product is precipitated after distillation and preservation, filtered and dried to obtain brominated polycarbonate.

[0118] Example 3

[0119] The present embodiment provides an environmentally friendly production method for continuously producing brominated polycarbonate, specifically:

[0120] 1. First photocatalytic decomposition

[0121] Take 75 g of triphosgene and the first solvent (200 g of toluene, 400 g of carbon tetrachloride), add to a blue cap bottle, seal, shake and obtain a triphosgene solution, then place it in a glove box; open the triphosgene solution feed pump, continuously input the triphosgene solution into the reaction pipeline of the first photocatalytic reactor at a feed rate of 5 mL / min, control the first photocatalytic decomposition temperature to be 30°C in the light environment, and the residence time of the triphosgene solution in the reaction pipeline is 5 min, continuously photocatalyze the triphosgene; the obtained first photocatalytic decomposition product is continuously introduced into the micro-mixer through the static mixer.

[0122] Among them, in order to initiate the free radical reaction of photocatalytic decomposition of triphosgene, the wavelength of the light source is 280 nm.

[0123] The first catalyst is zinc oxide; the concentration of the first catalyst is 0.5 mg / mL.

[0124] 2、Second photocatalytic decomposition

[0125] Take the aminocarbonyl compound (6 g of urea) and the second solvent (100 mL of deionized water), add to a blue cap bottle, seal, shake and obtain a urea solution; open the aminocarbonyl compound solution feed pump, continuously input the urea solution into the reaction pipeline of the second photocatalytic reactor at a feed rate of 1 mL / min, control the second photocatalytic decomposition temperature to be 45°C in the light environment, and the residence time of the urea solution in the reaction pipeline is 5 min, continuously photocatalyze the urea; the obtained second photocatalytic decomposition product is continuously introduced into the micro-mixer through the static mixer.

[0126] Among them, in order to promote the decomposition of aminocarbonyl compounds, enough energy is provided by ultraviolet light to break the chemical bonds in the aminocarbonyl compound molecules, and the wavelength of the light source is 365 nm.

[0127] The second catalyst is octacarbonyldicobalt; the concentration of the second catalyst is 2.5 mg / mL.

[0128] 3、Micro-channel polymerization reaction

[0129] The first photocatalytic decomposition product and the second photocatalytic decomposition product are pre-mixed by the static mixer and continuously introduced into the micro-mixer for mixing as the first material into the mixing coil; at the same time, open the four-brominated bisphenol A mixed solution feed pump (pump 3) as the second material into the mixing coil; after the first material and the second material are mixed into a mixed solution in the mixing coil at a temperature of 18°C, continuously enter the first micro-reactor and its reaction coil at a feed rate of 9 g / min, control the reaction temperature to be 37°C, and the residence time of the material is 117.58 s, after the polymerization reaction, continuously obtain the polymerization reaction product.

[0130] The second material (a mixed solution of tetrabromobisphenol A) is composed of 333 g of tetrabromobisphenol A, 65 g of sodium hydroxide (an alkaline compound), 80 g of a capping agent phenol, 580 g of deionized water, and 580 g of toluene (an organic solvent).

[0131] The mass ratio of the first material to the second material in the mixed solution is 828:1638.

[0132] 4. Purification

[0133] The polymerization product and deionized water (a washing liquid) are continuously fed into the second micro-reactor, the washing and purification temperature is controlled at 25°C, and the material residence time is 3 min. After washing and purification, a washing and purification product is continuously obtained.

[0134] The volume ratio of the washing liquid to the polymerization product is 1:2.

[0135] 5. Post-treatment

[0136] The washing and purification product is added to water, heated to boiling, and the product is precipitated after distillation and desolventization. After filtration and drying, brominated polycarbonate is obtained.

[0137] The molecular weight and molecular weight distribution of the brominated polycarbonate obtained in Examples 1-3 are detected, and the specific detection results are shown in the following table:

[0138]

[0139] Example 4

[0140] The technical solution of Example 1 is adopted in this example, and the changes are as follows: (1) the mass of the capping agent phenol in the second material in the micro-channel polymerization step is changed to 60 g. (2) The material residence time in the micro-channel polymerization step is changed to 156.77 s.

[0141] As Figure 1 The gel permeation chromatogram of the brominated polycarbonate obtained in Example 4 shows that the molecular weight distribution of the prepared brominated polycarbonate is narrow and concentrated. Example 5

[0142] The technical solution of Example 1 is adopted in this example, and the changes are as follows: (1) the mass of the capping agent phenol in the second material in the micro-channel polymerization step is changed to 40 g. (2) The material residence time in the micro-channel polymerization step is changed to 156.77 s. Example 6

[0143] The embodiment adopts the technical scheme of the embodiment 1, and changes are made as follows: (1) the mass of the end-capping agent phenol in the second material in the micro-channel polymerization step is changed to 20 g. (2) the residence time of the material in the micro-channel polymerization step is changed to 156.77 s.

[0144] The molecular weight and the molecular weight distribution of the brominated polycarbonate prepared in the embodiment 4-6 are detected respectively, and the specific detection results are shown in the following table:

[0145]

[0146] Embodiment 7

[0147] The embodiment adopts the technical scheme of the embodiment 1, and changes are made as follows: the residence time of the material in the micro-channel polymerization step is changed to 78.39 s. Embodiment 8

[0148] The embodiment adopts the technical scheme of the embodiment 1, and changes are made as follows: the residence time of the material in the micro-channel polymerization step is changed to 156.77 s. Embodiment 9

[0149] The embodiment adopts the technical scheme of the embodiment 1, and changes are made as follows: the residence time of the material in the micro-channel polymerization step is changed to 235.16 s.

[0150] As Figure 2 can be seen from the gel permeation chromatogram of the brominated polycarbonate prepared in the embodiment 9, the molecular weight distribution of the prepared brominated polycarbonate is narrow and concentrated.

[0151] The molecular weight and the molecular weight distribution of the brominated polycarbonate prepared in the embodiment 7-9 are detected respectively, and the specific detection results are shown in the following table:

[0152]

[0153] Further, the particle size and the particle size distribution of the brominated polycarbonate prepared in the embodiment 1-9 are detected respectively, and the specific detection results are shown in the following table: Figure 3 As can be seen, the particle size distribution of the brominated polycarbonate prepared in each embodiment is concentrated; and the environment-friendly production method for continuously producing brominated polycarbonate can realize high-precision control of the molecular weight, the molecular weight distribution and the particle size distribution of the prepared brominated polycarbonate.

[0154] It can be seen that the continuous production of brominated polycarbonate environmentally friendly production method of the application, the first photocatalytic decomposition of the continuous production of brominated polycarbonate, the first photocatalytic decomposition product is obtained; the second photocatalytic decomposition of the amino carbonyl compound is carried out, and the second photocatalytic decomposition product is obtained; the first photocatalytic decomposition product and the second photocatalytic decomposition product are mixed as the first material, and the second material (tetrabromobisphenol A mixed solution) is mixed and subjected to microchannel polymerization reaction, and then purified and treated to obtain brominated polycarbonate; each technical means cooperates and synergizes, and photocatalytic decomposition of triphosgene and photocatalytic decomposition of amino carbonyl compound are simultaneously used, which are decomposed in a photocatalytic environment in a safe, environmentally friendly, efficient and low energy consumption manner, effectively preventing phosgene leakage, reducing the unit reaction phosgene and content, and increasing the service life of the catalyst; at the same time, the static mixer is used for premixing, which further reduces the reaction time and improves the reaction efficiency; further, the microreactor is used for continuous polymerization reaction, which reduces the reaction equivalent and improves the reaction rate, and cooperates with the addition amount of the end-capping agent and the polymerization reaction related process parameters to accurately control the molecular weight and particle size distribution of the brominated polycarbonate; and the microreactor is used for washing, which further improves the production rate and ensures the quality of the brominated polycarbonate product; the problems of high catalyst cost, short catalyst life, easy to produce by-products, low reaction efficiency, complicated process flow and poor safety in the existing industrial production method of brominated polycarbonate can be effectively overcome; the molecular weight, molecular weight distribution and particle size distribution of the prepared brominated polycarbonate can be accurately controlled.

[0155] Unless otherwise stated, the percentages used in the present application are mass percentages.

[0156] Finally, it should be noted that: the above only describes the preferred embodiments of the present application, and is not used to limit the present application, although the present application has been described in detail with reference to the foregoing embodiments, and for those skilled in the art, the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An environmentally friendly production method for continuously producing brominated polycarbonate, characterized by, The method comprises the following steps: first photocatalytic decomposition, second photocatalytic decomposition, micro-channel polymerization, purification, post-treatment. The first photocatalytic decomposition solution is continuously introduced into the reaction pipeline of the first photocatalytic reactor, and the first photocatalytic decomposition is continuously carried out under light in the presence of the first catalyst to continuously obtain the first photocatalytic decomposition product. The second photocatalytic decomposition solution is continuously introduced into the reaction pipeline of the second photocatalytic reactor, and the second photocatalytic decomposition is continuously carried out under light in the presence of the second catalyst to continuously obtain the second photocatalytic decomposition product. The first photocatalytic decomposition product and the second photocatalytic decomposition product are pre-mixed by the static mixer, and then continuously introduced into the micro-mixer for mixing to form a first material; the first material and a second material are mixed to form a mixed solution, and then continuously introduced into the first micro-reactor for polymerization to continuously obtain a polymerization product. In the micro-channel polymerization, the feeding rate of the mixed solution into the first micro-reactor is 5-20 g / min; the polymerization temperature is controlled to be 30-40 ℃, and the material residence time is 1-16 min. In the micro-channel polymerization, the mass ratio of the first photocatalytic decomposition product to the second photocatalytic decomposition product in the first material is 3-25:1; the second material is composed of tetrabromobisphenol A, an alkaline compound, an end-capping agent, deionized water and an organic solvent; and the mass ratio of the first material to the second material in the mixed solution is 753-971:1578-1638. The polymerization product and a washing solution are simultaneously introduced into the second micro-reactor for washing and purification to continuously obtain a washing and purification product. The washing and purification product is added into water, and then distilled to remove the solvent, so as to collect and dry the solid to obtain the brominated polycarbonate.

2. The environmentally friendly production method for continuously producing brominated polycarbonate according to claim 1, characterized by, In the first photocatalytic decomposition, the feeding rate of the triphosgene solution into the first photocatalytic reactor is 3-20 mL / min, the light wavelength is 100-280 nm, the first photocatalytic decomposition temperature is controlled to be 15-36 ℃, and the material residence time is 3-16 min. The triphosgene solution is composed of triphosgene and a first solvent, and the concentration of the triphosgene is 0.5-25 mol / L; the first solvent is at least one of toluene, chloroform, dihalomethane, dihaloethane, carbon tetrahalide, chlorinated benzene and dichlorobenzene.

3. The environmentally friendly production process for continuous production of brominated polycarbonate according to claim 1, characterized by, In the first photocatalytic decomposition, the first catalyst is at least one of titanium dioxide, nitrogen-doped titanium dioxide, zinc oxide, titanium nitride, carbon nitride, halogenated rare earth compound and tungstate compound. The concentration of the first catalyst is 0.3-0.5 mg / mL.

4. The environmentally friendly production process for continuously producing brominated polycarbonate according to claim 1, characterized by, In the second photocatalytic decomposition, the feeding rate of the aminocarbonyl compound solution into the second photocatalytic reactor is 0.5-10 mL / min, the light wavelength is 340-387 nm, the second photocatalytic decomposition temperature is controlled to be 30-50 ℃, and the material residence time is 1-12 min. The amino carbonyl compound solution is composed of an amino carbonyl compound and a second solvent, the concentration of the amino carbonyl compound is 1-25 mol / L; the amino carbonyl compound is one of the following: amino acid, amide, urea; the second solvent is at least one of the following: deionized water, methanol, ethanol.

5. The environmentally friendly production process for continuously producing brominated polycarbonate according to claim 1, characterized by, In the second photocatalytic decomposition, the second catalyst is at least one of the following: titanium dioxide, noble metal catalyst, transition metal catalyst, zinc oxide; The concentration of the second catalyst is 1-2.5 mg / mL.

6. The environmentally friendly production process for the continuous production of brominated polycarbonate according to claim 1, characterized by, The basic compound is one of the following: sodium hydroxide, potassium hydroxide, aluminum hydroxide, ammonia, potassium methoxide; The end-capping agent is phenol; The organic solvent is carbon tetrachloride or toluene; The weight ratio of tetrabromobisphenol A, basic compound, end-capping agent, deionized water, organic solvent in the second material is 333:65:20-80:580:

580.

7. The environmentally friendly production process for continuous production of brominated polycarbonate according to claim 1, characterized by, In the purification, the washing purification temperature is controlled to be 20-25℃, and the material residence time is 1-10 min; The washing liquid is at least one of the following: deionized water, methanol, acetone; The volume ratio of the washing liquid to the polymerization product is 1:1-5.

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