A method and system for preparing brominated polystyrene from styrene bromide

Abstract

This application relates to the field of olefin preparation technology, and more particularly to a method and system for preparing brominated polystyrene from styrene bromine. The method includes: mixing styrene and a first solvent, then treating the mixture with a refining agent to remove impurities, obtaining styrene raw material; polymerizing the styrene raw material using an initiator, then stopping the polymerization reaction using a termination agent, obtaining crude polystyrene; washing the crude polystyrene with a detergent, then vacuum drying and pulverizing it to obtain polystyrene particles; brominating a second solvent, a catalyst, a bromine source, and the polystyrene particles to obtain crude brominated polystyrene; purifying the crude brominated polystyrene to obtain the brominated polystyrene product; the bromination reaction temperature is ≤30℃, and the bromination reaction time is ≥8h. This method first controls the polymerization reaction to regulate the molecular weight of polystyrene, and then controls the bromination reaction to regulate the molecular weight of brominated polystyrene, thus improving the controllability of the molecular weight of brominated polystyrene.

Description

Technical Field

[0001] This application relates to the field of olefin preparation technology, and in particular to a method and system for preparing brominated polystyrene from styrene bromine. Background Technology

[0002] Common flame retardants are polybrominated biphenyls (PBPs) and polybrominated diphenyl ethers (PBDEs). While their production processes are mature, and they are inexpensive and readily available, these flame retardants produce carcinogenic dioxins and furans during combustion. Therefore, these traditional flame retardants are currently classified as toxic and hazardous substances, requiring strict restrictions on their use in electronic information products. Consequently, most electronic information products currently continue to use flame retardants that replace PBPs and PBDEs. Brominated polystyrene (BPS) is a novel additive polymeric flame retardant that has minimal impact on the physical and mechanical properties of the flame-retarded substrate. It features high bromine content, good heat resistance, minimal impact on resin impact resistance, resistance to exudation, and low toxicity. Furthermore, BPS has advantages such as low environmental and human health hazards, antistatic properties, and excellent processing performance. Given its low toxicity and environmental friendliness, BPS can effectively replace traditional flame retardants like PBPs and PBDEs.

[0003] Currently, the preparation of brominated polystyrene mostly uses polystyrene and bromine source as raw materials, and the brominated polystyrene is prepared by substitution reaction using bromine source. However, it is difficult to control the molecular weight of brominated polystyrene by using specific processes and parameters for its preparation. Summary of the Invention

[0004] This application provides a method and system for preparing brominated polystyrene from styrene bromine, in order to solve the following technical problem: how to improve the controllability of the molecular weight of brominated polystyrene.

[0005] In a first aspect, this application provides a method for preparing brominated polystyrene from styrene bromine, the method comprising:

[0006] Styrene and a first solvent are mixed, and then the mixture is purified using a refining agent to obtain styrene raw material;

[0007] The styrene raw material is polymerized using an initiator, and then the polymerization reaction is stopped using a stopper to obtain crude polystyrene.

[0008] The crude polystyrene product was washed with detergent, and then the washed crude polymer product was vacuum dried and pulverized to obtain polystyrene granules.

[0009] The second solvent, catalyst, bromine source and the polystyrene particles are subjected to a bromination reaction to obtain crude brominated polystyrene.

[0010] The crude brominated polystyrene was purified to obtain the brominated polystyrene product.

[0011] The bromination reaction is carried out at a temperature ≤30℃ and for a time ≥8h.

[0012] Optionally, the bromination reaction temperature is 3℃~30℃, and the bromination reaction time is 8h~16h.

[0013] Optionally, the weight m1 of the catalyst, the weight m2 of the bromine source, and the weight m3 of the polystyrene particles satisfy the relationship: m1:m2:m3=(0.04~0.17):(1.9~5.1):1; and / or

[0014] The weights m4 of the initiator, m5 of the terminating agent, and m6 of the styrene raw material satisfy the following relationship:

[0015] m4:m5:m6=(0.14~0.6):(0.02~0.4):1.

[0016] Optionally, the polymerization reaction temperature is 70℃~110℃, and the polymerization reaction time is 40min~120min.

[0017] Optionally, the bromine source includes bromine chloride, and the method for preparing the bromine chloride includes:

[0018] A chlorine source and a bromine source are reacted to produce bromine chloride.

[0019] Optionally, the temperature of the synthesis reaction is -25℃ to -5℃, and the time of the synthesis reaction is 8h to 16h.

[0020] Optionally, the refining agent includes at least one of the following:

[0021] Deoxidizers, molecular sieves, and desulfurizers; and / or

[0022] The initiator includes at least one of the following types:

[0023] n-Butyllithium, sec-Butyllithium, and ammonium persulfate; and / or

[0024] The type of terminating agent includes at least one of the following:

[0025] Dodecyl mercaptan, ethanol hydrochloride, and isopropanol; and / or

[0026] The detergent includes deionized water and / or sodium sulfite.

[0027] Optionally, the first solvent includes cyclohexane; and / or

[0028] The second solvent includes dichloromethane.

[0029] In a second aspect, embodiments of this application provide a system for preparing brominated polystyrene from styrene bromine, the system being adapted to the method described in the first aspect, the system comprising:

[0030] A polystyrene preparation unit includes a styrene refining tank, a cyclohexane refining tank, a polymerization reactor, an initiator pipeline, a stop agent pipeline, a coagulation reactor, and a polystyrene vacuum drying device. The polymerization reactor is equipped with multiple auxiliary material inlets and multiple raw material inlets. The initiator pipeline and the stop agent pipeline are respectively connected to the auxiliary material inlets of the polymerization reactor. The outlets of the styrene refining tank and the cyclohexane refining tank are connected to the inlets of the polymerization reactor. The outlet of the polymerization reactor is connected to the inlet of the coagulation reactor, and the outlet of the coagulation reactor is connected to the inlet of the polystyrene vacuum drying device.

[0031] The bromine source preparation unit includes a liquid chlorine pipeline, a liquid chlorine vaporizer, a liquid bromine pipeline, a cooling water pipeline, and a bromine chloride synthesis reactor. The liquid chlorine pipeline is connected to the inlet of the liquid chlorine vaporizer, the outlet of the liquid chlorine vaporizer is connected to the air inlet of the bromine chloride synthesis reactor, and the liquid bromine pipeline and the cooling water pipeline are respectively connected to the liquid inlet of the bromine chloride synthesis reactor.

[0032] A brominated polystyrene preparation unit includes a dichloromethane pipeline, a catalyst pipeline, and a bromination reactor. The outlet of the bromine chloride synthesis reactor is connected to the inlet of the bromination reactor, the outlet of the dichloromethane pipeline is connected to the liquid inlet of the bromination reactor, and the outlet of the catalyst pipeline is connected to the inlet of the bromination reactor.

[0033] A post-processing unit, which is connected to the outlet of the bromination reactor.

[0034] Optionally, the post-processing unit includes a washing section, a flash crystallization section, and a drying and granulation section. The washing section includes: a first demineralized water pipe, a sodium sulfite pipe, a first washing vessel, a second washing vessel, and a third washing vessel. The inlet of the first washing vessel is connected to the outlet of the bromination vessel. The inlet of the second washing vessel is connected to the outlet of the first washing vessel. The inlet of the third washing vessel is connected to the outlet of the second washing vessel. The first demineralized water pipe is connected to the first washing vessel, the second washing vessel, and the third washing vessel. The sodium sulfite pipe is connected to the second washing vessel.

[0035] The flash crystallization section includes a second demineralized water pipe, an acid-base adjustment pipe, a flash evaporator, and a centrifuge. The outlets of the second demineralized water pipe and the acid-base adjustment pipe are respectively connected to the inlet of the flash evaporator. The inlet of the flash evaporator is connected to the outlet of the third washing tank. The outlet of the flash evaporator is connected to the inlet of the centrifuge.

[0036] The drying and granulation section includes a dryer and an extrusion granulator. The feed inlet of the dryer is connected to the discharge outlet of the centrifuge, and the discharge outlet of the dryer is connected to the feed inlet of the extrusion granulator.

[0037] The technical solutions provided in this application have the following advantages compared with the prior art:

[0038] This application provides a method for preparing brominated polystyrene from styrene bromine. This method first controls the start and end of the polymerization reaction of styrene using an initiator and a terminator, thereby controlling the degree of polymerization of styrene during the polymerization process and thus controlling the molecular weight of the crude polystyrene. Furthermore, by maintaining a bromination reaction temperature ≤30℃ and a bromination reaction time ≥8h, the polystyrene and bromine source can undergo bromination in a second solvent under the catalytic action of a catalyst, controlling the process of bromine substitution of groups in the polystyrene. This allows for the regulation of the bromine distribution in the polystyrene, thereby adjusting the molecular weight of the brominated polystyrene. Therefore, this method first controls the molecular weight of polystyrene by controlling the polymerization reaction process, and then controls the molecular weight of the brominated polystyrene by controlling the bromination reaction process, thereby improving the controllability of the molecular weight of brominated polystyrene. Attached Figure Description

[0039] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0040] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This application provides a schematic flowchart of a method for preparing brominated polystyrene from styrene bromine.

[0042] Figure 2 This application provides a schematic diagram of a system structure for preparing brominated polystyrene from styrene bromine.

[0043] Figure 3This is a schematic diagram of an actual system for preparing brominated polystyrene from styrene bromine, provided in an embodiment of this application.

[0044] Among them, 1-styrene refining tank, 2-cyclohexane refining tank, 3-polymerization reactor, 4-condensation reactor, 5-polystyrene vacuum drying device, 6-liquid chlorine vaporizer, 7-bromine chloride synthesis reactor, 8-bromination reactor, 9-first washing reactor, 10-second washing reactor, 11-third washing reactor, 12-flash evaporator, 13-centrifuge, 14-dryer, 15-extrusion granulator, 101-initiator pipeline, 102-terminating agent pipeline, 103-liquid chlorine pipeline, 104-liquid bromine pipeline, 105-cooling water pipeline, 106-dichloromethane pipeline, 107-catalyst pipeline, 108-first demineralized water pipeline, 109-sodium sulfite pipeline, 110-second demineralized water pipeline, 111-acid-base adjustment pipeline. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0046] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range; for example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range such as 1, 2, 3, 4, 5, and 6, regardless of the range; in addition, whenever a numerical range is indicated herein, it means including any referenced number (fraction or integer) within the indicated range.

[0047] In this document, terms such as "comprising" mean "including but not limited to". Relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone; where A and B can be singular or plural.

[0048] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this article can be purchased from the market or prepared by existing methods.

[0049] Figure 1 An exemplary schematic diagram of a method for preparing brominated polystyrene from styrene bromine provided in an embodiment of this application is shown.

[0050] like Figure 1 As shown in the embodiments of this application, a method for preparing brominated polystyrene from styrene bromine is provided, the method comprising:

[0051] S1. Styrene and the first solvent are mixed, and then the mixture is purified using a refining agent to obtain styrene raw material;

[0052] S2. The styrene raw material is polymerized using an initiator, and then the polymerization reaction is stopped using a stopper to obtain crude polystyrene.

[0053] S3. The crude polystyrene product is washed with detergent, and then the washed crude polymer product is vacuum dried and pulverized to obtain polystyrene particles;

[0054] S4. The second solvent, catalyst, bromine source and the polystyrene particles are subjected to a bromination reaction to obtain crude brominated polystyrene;

[0055] S5. The crude brominated polystyrene is purified to obtain the brominated polystyrene product;

[0056] The bromination reaction is carried out at a temperature ≤30℃ and for a time ≥8h.

[0057] It should be noted that the detergent used for this washing can be demineralized water, sodium sulfite solution, or a mixture of demineralized water and sodium sulfite solution.

[0058] It should be noted that this impurity removal treatment uses a refining agent to remove impurities from styrene and the first solvent.

[0059] It should be noted that the purification process can be washing, flash crystallization, or drying granulation.

[0060] In some optional embodiments, the bromination reaction is carried out at a temperature of 3°C to 30°C and for a duration of 8 hours to 16 hours.

[0061] In these methods, the bromination reaction temperature can be 3℃ to 30℃, and the bromination reaction time can be 8h to 16h. Polystyrene and bromine source can be fully brominated in a second solvent under the catalytic action of a catalyst. Furthermore, the process of bromine substituting groups in polystyrene during the bromination reaction can be controlled to regulate the distribution of bromine in polystyrene, thereby adjusting the molecular weight of brominated polystyrene.

[0062] The bromination reaction can be performed at temperatures of 3°C, 4°C, 5°C, 10°C, 15°C, 20°C, 25°C, or 30°C.

[0063] The bromination reaction can take 8 hours, 10 hours, 12 hours, 14 hours, or 16 hours.

[0064] In some optional embodiments, the weight m1 of the catalyst, the weight m2 of the bromine source, and the weight m3 of the polystyrene particles satisfy the relationship: m1:m2:m3 = (0.04~0.17):(1.9~5.1):1; and / or

[0065] The weights m4 of the initiator, m5 of the terminating agent, and m6 of the styrene raw material satisfy the following relationship:

[0066] m4:m5:m6=(0.14~0.6):(0.02~0.4):1;

[0067] In these embodiments, the weights of the catalyst (m1), bromine source (m2), and polystyrene particles (m3) satisfy the relationship: m1:m2:m3 = (0.04–0.17):(1.9–5.1):1. This allows for the full bromination reaction of the polystyrene particles and bromine source under the catalytic action of the catalyst. Furthermore, it allows for the control of the rate at which bromine replaces groups in the polystyrene during the bromination process, thereby regulating the distribution of bromine in the polystyrene and adjusting the molecular weight of the brominated polystyrene. Additionally, the weights of the initiator (m4), terminating agent (m5), and styrene raw material (m6) satisfy the relationship: m4:m5:m6 = (0.14–0.6):(0.02–0.4):1. This allows for further control of the polymerization process of styrene using the initiator and terminating agent, thereby controlling the degree of polymerization and ultimately the molecular weight of the crude polystyrene.

[0068] The weight m1 of the catalyst can be 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16 or 0.17; the weight m2 of the bromine source can be 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.6, 4.1, 4.6 or 5.1.

[0069] The weight m4 of the initiator can be 0.14, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, or 0.60; the weight m5 of the terminating agent can be 0.02, 0.03, 0.04, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, or 0.60.

[0070] In some optional embodiments, the polymerization reaction is carried out at a temperature of 70°C to 110°C and for a duration of 40 min to 120 min.

[0071] In these embodiments, the polymerization temperature can be 70°C to 110°C, and the polymerization time can be 40 min to 120 min, which can promote the full polymerization of styrene. It is convenient to control the degree of polymerization of styrene in the polymerization process by using initiators and terminators, thereby controlling the molecular weight of crude polystyrene.

[0072] The polymerization reaction can be carried out at temperatures of 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, or 110°C.

[0073] The polymerization reaction can take 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, or 120 min.

[0074] In some optional embodiments, the bromine source includes bromine chloride, and the method for preparing the bromine chloride includes:

[0075] S401. A chlorine source and a bromine source are reacted to produce bromine chloride;

[0076] In these embodiments, the bromine source may include bromine chloride, as well as bromine chloride synthesized by combining chlorine and bromine sources. Bromine chloride can be used as the bromine source to facilitate a more complete bromination reaction between bromine chloride and polystyrene particles. At the same time, the process of bromine chloride replacing groups in polystyrene during the bromination reaction can be controlled to regulate the distribution of bromine chloride in polystyrene, thereby adjusting the molecular weight of brominated polystyrene.

[0077] In some optional embodiments, the temperature of the synthesis reaction is -25°C to -5°C, and the time of the synthesis reaction is 8h to 16h;

[0078] In these embodiments, the temperature of the synthesis reaction can be -25°C to -5°C, and the reaction time can be 8h to 16h, so as to promote sufficient synthesis reaction between the chlorine source and the bromine source to obtain sufficient bromine chloride.

[0079] The temperature for this synthesis reaction can be -25℃, -20℃, -15℃, -10℃, or -5℃.

[0080] The reaction time can be 8h, 10h, 12h, 14h or 16h.

[0081] In some alternative embodiments, the refining agent comprises at least one of the following:

[0082] Deoxidizers, molecular sieves, and desulfurizers; and / or

[0083] The initiator includes at least one of the following types:

[0084] n-Butyllithium, sec-Butyllithium, and ammonium persulfate; and / or

[0085] The type of terminating agent includes at least one of the following:

[0086] Dodecyl mercaptan, ethanol hydrochloride, and isopropanol; and / or

[0087] The detergent includes demineralized water and / or sodium sulfite;

[0088] In these embodiments, the refining agent includes at least one of a deoxidizer, a molecular sieve, and a desulfurizer. The refining agent is used to thoroughly remove impurities from styrene and the first solvent through impurity removal treatment, so as to facilitate the subsequent obtaining of a pure polystyrene product. In addition, the initiator may include at least one of n-butyllithium, sec-butyllithium, and ammonium persulfate, and the terminator may include dodecyl mercaptan, ethanol hydrochloride, and isopropanol. The degree of polymerization of styrene in the polymerization reaction process is controlled by the initiator and the terminator, thereby controlling the molecular weight of the crude polystyrene product. Furthermore, the detergent may include deionized water and / or sodium sulfite, which can thoroughly remove impurities from the crude polystyrene product to obtain a pure polystyrene product.

[0089] In some alternative embodiments, the first solvent comprises cyclohexane; and / or

[0090] The second solvent includes dichloromethane;

[0091] In these embodiments, the first solvent may include cyclohexane, which can fully disperse the initiator and styrene to promote the polymerization reaction of styrene under the action of the initiator; the second solvent may include dichloromethane, which can effectively disperse the catalyst, bromine source and polystyrene particles to promote the bromination reaction between the bromine source and polystyrene particles under the catalytic action of the catalyst, thereby obtaining a brominated polystyrene product.

[0092] Figure 2 An exemplary schematic diagram of a system structure for preparing brominated polystyrene from styrene bromine provided in an embodiment of this application is shown;

[0093] Figure 3 An exemplary schematic diagram of an actual system for preparing brominated polystyrene from styrene bromine provided in an embodiment of this application is shown;

[0094] Based on a general inventive concept, such as Figure 2 and Figure 3 As shown in the embodiments of this application, a system for preparing brominated polystyrene from styrene bromine is provided. The system is adapted to the method described above and includes:

[0095] A polystyrene preparation unit includes a styrene refining tank 1, a cyclohexane refining tank 2, a polymerization reactor 3, an initiator pipeline 101, a stop agent pipeline 102, a coagulation reactor 4, and a polystyrene vacuum drying device 5. The polymerization reactor 3 is provided with multiple auxiliary material inlets and multiple raw material inlets. The initiator pipeline 101 and the stop agent pipeline 102 are respectively connected to the auxiliary material inlets of the polymerization reactor 3. The outlets of the styrene refining tank 1 and the cyclohexane refining tank 2 are connected to the inlets of the polymerization reactor 3. The outlet of the polymerization reactor 3 is connected to the inlet of the coagulation reactor 4, and the outlet of the coagulation reactor 4 is connected to the inlet of the polystyrene vacuum drying device 5.

[0096] The bromine source preparation unit includes a liquid chlorine pipeline 103, a liquid chlorine vaporizer 6, a liquid bromine pipeline 104, a cooling water pipeline 105, and a bromine chloride synthesis reactor 7. The liquid chlorine pipeline 103 is connected to the inlet of the liquid chlorine vaporizer 6, the outlet of the liquid chlorine vaporizer 6 is connected to the air inlet of the bromine chloride synthesis reactor 7, and the liquid bromine pipeline 104 and the cooling water pipeline 105 are respectively connected to the liquid inlet of the bromine chloride synthesis reactor 7.

[0097] The brominated polystyrene preparation unit includes a dichloromethane pipeline 106, a catalyst pipeline 107, and a bromination reactor 8. The outlet of the bromine chloride synthesis reactor 7 is connected to the inlet of the bromination reactor 8, the outlet of the dichloromethane pipeline 106 is connected to the liquid inlet of the bromination reactor 8, and the outlet of the catalyst pipeline 107 is connected to the inlet of the bromination reactor 8.

[0098] A post-processing unit is connected to the outlet of the bromination reactor 8.

[0099] The system is implemented based on the above method. The specific steps of the method can be referred to the above embodiments. Since the system adopts some or all of the technical solutions of the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated here.

[0100] In some optional embodiments, the post-processing unit includes a washing section, a flash crystallization section, and a drying and granulation section. The washing section includes: a first demineralized water pipe 108, a sodium sulfite pipe 109, a first washing vessel 9, a second washing vessel 10, and a third washing vessel 11. The inlet of the first washing vessel 9 is connected to the outlet of the bromination vessel 8. The inlet of the second washing vessel 10 is connected to the outlet of the first washing vessel 9. The inlet of the third washing vessel 11 is connected to the outlet of the second washing vessel 10. The first demineralized water pipe 108 is connected to the first washing vessel 9, the second washing vessel 10, and the third washing vessel 11. The sodium sulfite pipe 109 is connected to the second washing vessel 10.

[0101] The flash crystallization section includes a second demineralized water pipe 110, an acid-base adjustment pipe 111, a flash evaporator 12, and a centrifuge 13. The outlets of the second demineralized water pipe 110 and the acid-base adjustment pipe 111 are respectively connected to the inlet of the flash evaporator 12. The liquid inlet of the flash evaporator 12 is connected to the outlet of the third washing vessel 11. The liquid outlet of the flash evaporator 12 is connected to the inlet of the centrifuge 13.

[0102] The drying and granulation section includes a dryer 14 and an extrusion granulator 15. The feed inlet of the dryer 14 is connected to the discharge outlet of the centrifuge 13, and the discharge outlet of the dryer 14 is connected to the feed inlet of the extrusion granulator 15.

[0103] In these embodiments, the post-treatment unit may include a washing section, which may include a first demineralized water pipe 108, a sodium sulfite pipe 109, a first washing vessel 9, a second washing vessel 10, and a third washing vessel 11. Demineralized water is introduced into the first washing vessel 9, the second washing vessel 10, and the third washing vessel 11 through the first demineralized water pipe 108 to thoroughly wash away impurities in the crude brominated polystyrene. Additionally, sodium sulfite is introduced into the second washing vessel 10 through the sodium sulfite pipe 109 to effectively improve the washing effect of the demineralized water, resulting in a purer brominated polystyrene. Furthermore, the post-treatment unit may include a flash crystallization section, which may include the second demineralized water pipe 11. 0. The acid-base adjustment pipeline 111, flash evaporator 12, and centrifuge 13 allow for further washing of the brominated polystyrene in the flash evaporator 12 via the second demineralized water pipeline 110 to remove impurities. An acid-base regulator can then be introduced through the acid-base adjustment pipeline 111 to further remove impurities. Finally, the brominated polystyrene and impurities are separated by centrifugation in the centrifuge 13. Furthermore, the post-processing unit may include a drying and granulation section, which may include a dryer 14 and an extrusion granulator 15. The dryer 14 dries the brominated polystyrene flowing out of the flash crystallization section into a solid state, and finally, the brominated polystyrene product is formed through extrusion granulation.

[0104] It should be noted that the workflow of this system is as follows: A refining agent is introduced into the styrene raw material in styrene refining tank 1 and the cyclohexane solvent in cyclohexane refining tank 2 to remove impurities from the cyclohexane and styrene, thus completing the raw material refining stage. Then, nitrogen gas is introduced into the polymerization reactor 3. Next, the cyclohexane from the cyclohexane refining tank 2 and the initiator from initiator pipeline 101 are respectively introduced into the polymerization reactor 3 for stirring. Then, the styrene raw material from the styrene refining tank 1 is introduced into the polymerization reactor 3 for polymerization. After the predetermined reaction time, the reaction proceeds through the stop agent pipeline 102. A stopping agent is introduced to stop the polymerization reaction and control the molecular weight of polystyrene, resulting in crude polystyrene. The crude polystyrene is then introduced into a coagulation reactor 4, followed by the introduction of an equal volume of detergent. After stirring evenly, the crude polystyrene is allowed to stand until it separates into layers. After multiple washings, a polystyrene product is obtained. The polystyrene product is then subjected to heating and vacuum drying in a polystyrene vacuum drying device 5 to remove residual cyclohexane solvent and detergent, resulting in a polystyrene product. Finally, the polystyrene product is pulverized and sieved to obtain a powdered polystyrene product.

[0105] Liquid bromine is introduced into the bromine chloride synthesis reactor 7 and stirred. Then, low-temperature cooling water is introduced through the cooling water pipe 105 to control the temperature inside the bromine chloride synthesis reactor 7, so that the liquid bromine is in a liquid state. After the temperature inside the bromine chloride synthesis reactor 7 is stable, liquid chlorine is introduced into the liquid chlorine vaporizer 6 through the liquid chlorine pipe 103 to obtain chlorine gas. The chlorine gas is then introduced into the bromine chloride synthesis reactor 7 to carry out the synthesis reaction and obtain the bromine chloride product.

[0106] The polystyrene product and bromine chloride product obtained above are introduced into the bromination reactor 8. Then, dichloromethane is introduced into the bromination reactor 8 through the dichloromethane pipe 106 and the catalyst is introduced into the bromination reactor 8 through the catalyst pipe 107. Under the catalytic action of the catalyst, the polystyrene product and the bromine chloride product undergo a bromination reaction to obtain crude brominated polystyrene.

[0107] The obtained crude brominated polystyrene is injected into the first washing vessel 9. Then, demineralized water is introduced into the first washing vessel 9 through the first demineralized water pipe 108 and stirred. After settling and separation, the lower brominated reactant is injected into the second washing vessel 10. Then, demineralized water and sodium sulfite are introduced into the second washing vessel 10 through the first demineralized water pipe 108 and the sodium sulfite pipe 109 and stirred. After settling and separation, the lower brominated reactant is injected into the third washing vessel 11. Demineralized water is introduced into the third washing vessel 11 through the first demineralized water pipe 108. After settling and separation, the lower layer yields brominated polystyrene. The bromination reactant is introduced into the flash evaporator 12, and then demineralized water is introduced into the flash evaporator 12 through the second demineralized water pipe 110. At the same time, hot water is introduced into the jacket of the flash evaporator 12, and the demineralized water and the brominated polystyrene reactant are stirred and heated. Then, sodium carbonate solution is introduced into the flash evaporator 12 through the acid-base adjustment pipe 111 to promote the acidity and alkalinity of the material in the flash evaporator 12 to slightly alkaline. The hot water is then stopped from being introduced into the jacket of the flash evaporator 12 to lower the temperature of the flash evaporator 12. Then, the material in the flash evaporator 12 is introduced into the centrifuge 13 for centrifugation to remove moisture, and the brominated polystyrene centrifuged material is obtained.

[0108] The centrifuged brominated polystyrene material is fed into the dryer 14 for drying, and then the dried material is fed into the extrusion granulator 15 for extrusion granulation to obtain irregularly shaped brominated polystyrene granules. Then, using nitrogen as the gas source and a blower, the brominated polystyrene granules are transported to the packaging silo. The brominated polystyrene granules stored in the packaging silo are then packaged into 25kg packaging bags, and then the packaging bags are stacked by gravity.

[0109] Example 1

[0110] like Figure 1 As shown, a method for preparing brominated polystyrene from styrene bromine includes:

[0111] S1. Styrene and the first solvent are mixed, and then the mixture is purified using a refining agent to obtain styrene raw material;

[0112] S2. Styrene raw material is polymerized using an initiator, and then the polymerization reaction is stopped using a stopper to obtain crude polystyrene.

[0113] S3. Wash the crude polystyrene product with detergent, then vacuum dry and pulverize the washed crude polymer product to obtain polystyrene granules;

[0114] S401. A chlorine source and a bromine source are reacted to produce bromine chloride;

[0115] S4. The second solvent, catalyst, bromine source and polystyrene particles are subjected to a bromination reaction to obtain crude brominated polystyrene;

[0116] S5. Purify the crude brominated polystyrene to obtain the brominated polystyrene product;

[0117] The bromination reaction was carried out at a temperature of 27°C for 13 hours.

[0118] The weights of the catalyst (m1), the bromine source (m2), and the polystyrene particles (m3) satisfy the following relationship:

[0119] m1:m2:m3 = 0.1:3.9:1;

[0120] The weights of the initiator (m4), the terminating agent (m5), and the styrene raw material (m6) satisfy the following relationship:

[0121] m4:m5:m6 = 0.2:0.03:1.

[0122] The polymerization reaction was carried out at a temperature of 72℃ for 60 minutes.

[0123] The synthesis reaction was carried out at a temperature of -15℃ for 12 hours.

[0124] The refining agent is a mixture of deoxidizer, molecular sieve and desulfurizer; the initiator is a mixture of n-butyllithium, sec-butyllithium and ammonium persulfate; the stopping agent is a mixture of dodecyl mercaptan, ethanol hydrochloride and isopropanol.

[0125] The detergent is deionized water and sodium sulfite.

[0126] The first solvent is cyclohexane; the second solvent is dichloromethane.

[0127] like Figure 2 and Figure 3 As shown, a system for preparing brominated polystyrene from styrene bromine includes:

[0128] The polystyrene preparation unit includes a styrene refining tank 1, a cyclohexane refining tank 2, a polymerization reactor 3, an initiator pipeline 101, a stop agent pipeline 102, a coagulation reactor 4, and a polystyrene vacuum drying device 5. The polymerization reactor 3 is equipped with multiple auxiliary material inlets and multiple raw material inlets. The initiator pipeline 101 and the stop agent pipeline 102 are respectively connected to the auxiliary material inlets of the polymerization reactor 3. The outlets of the styrene refining tank 1 and the cyclohexane refining tank 2 are connected to the inlets of the polymerization reactor 3. The outlet of the polymerization reactor 3 is connected to the inlet of the coagulation reactor 4, and the outlet of the coagulation reactor 4 is connected to the inlet of the polystyrene vacuum drying device 5.

[0129] The bromine source preparation unit includes a liquid chlorine pipeline 103, a liquid chlorine vaporizer 6, a liquid bromine pipeline 104, a cooling water pipeline 105, and a bromine chloride synthesis reactor 7. The liquid chlorine pipeline 103 is connected to the inlet of the liquid chlorine vaporizer 6, the outlet of the liquid chlorine vaporizer 6 is connected to the air inlet of the bromine chloride synthesis reactor 7, and the liquid bromine pipeline 104 and the cooling water pipeline 105 are respectively connected to the liquid inlet of the bromine chloride synthesis reactor 7.

[0130] The brominated polystyrene preparation unit includes a dichloromethane pipeline 106, a catalyst pipeline 107, and a bromination reactor 8. The outlet of the bromine chloride synthesis reactor 7 is connected to the inlet of the bromination reactor 8, the outlet of the dichloromethane pipeline 106 is connected to the liquid inlet of the bromination reactor 8, and the outlet of the catalyst pipeline 107 is connected to the inlet of the bromination reactor 8.

[0131] The post-treatment unit is connected to the outlet of the bromination reactor 8. The post-treatment unit includes a washing section, a flash crystallization section, and a drying and granulation section. The washing section includes: a first demineralized water pipe 108, a sodium sulfite pipe 109, a first washing reactor 9, a second washing reactor 10, and a third washing reactor 11. The inlet of the first washing reactor 9 is connected to the outlet of the bromination reactor 8; the inlet of the second washing reactor 10 is connected to the outlet of the first washing reactor 9; and the inlet of the third washing reactor 11 is connected to the outlet of the second washing reactor 10. The first demineralized water pipe 108 is connected to the first washing reactor 9, the second washing reactor 10, and the third washing reactor 11. The sodium sulfite pipe 109 is connected to the second washing reactor 10.

[0132] The flash crystallization section includes a second demineralized water pipe 110, an acid-base adjustment pipe 111, a flash evaporator 12, and a centrifuge 13. The outlets of the second demineralized water pipe 110 and the acid-base adjustment pipe 111 are respectively connected to the inlet of the flash evaporator 12. The inlet of the flash evaporator 12 is connected to the outlet of the third washing vessel 11. The outlet of the flash evaporator 12 is connected to the inlet of the centrifuge 13.

[0133] The drying and granulation section includes a dryer 14 and an extrusion granulator 15. The feed inlet of the dryer 14 is connected to the discharge outlet of the centrifuge 13, and the discharge outlet of the dryer 14 is connected to the feed inlet of the extrusion granulator 15.

[0134] Example 2

[0135] Based on the content disclosed in Example 1, the following modifications are made:

[0136] The bromination reaction was carried out at a temperature of 15°C for 13 hours.

[0137] The weights of the catalyst (m1), the bromine source (m2), and the polystyrene particles (m3) satisfy the following relationship:

[0138] m1:m2:m3 = 0.05:4:1;

[0139] The weights of the initiator (m4), the terminating agent (m5), and the styrene raw material (m6) satisfy the following relationship:

[0140] m4:m5:m6 = 0.6:0.037:1.

[0141] The polymerization reaction was carried out at a temperature of 90℃ for 40 minutes.

[0142] The synthesis reaction was carried out at a temperature of -15℃ for 12.5 hours.

[0143] Example 3

[0144] Based on the content disclosed in Example 1, the following modifications are made:

[0145] The bromination reaction was carried out at a temperature of 20°C for 13 hours.

[0146] The weights of the catalyst (m1), the bromine source (m2), and the polystyrene particles (m3) satisfy the following relationship:

[0147] m1:m2:m3 = 0.10:5.0:1;

[0148] The weights of the initiator (m4), the terminating agent (m5), and the styrene raw material (m6) satisfy the following relationship:

[0149] m4:m5:m6 = 0.5:0.04:1.

[0150] The polymerization reaction was carried out at a temperature of 85℃ for 50 minutes.

[0151] The synthesis reaction was carried out at a temperature of -15℃ for 12.5 hours.

[0152] Comparative Example 1

[0153] Based on the content disclosed in Example 1, the following modifications are made:

[0154] Instead of using a bromine chloride synthesis reactor, existing commercial bromine chloride is directly introduced.

[0155] Comparative Example 2

[0156] Based on the content disclosed in Example 1, the following modifications are made:

[0157] The synthesis reaction was carried out at a temperature of 2℃ for 6 hours.

[0158] Comparative Example 3

[0159] Based on the content disclosed in Example 1, the following modifications are made:

[0160] The synthesis reaction was carried out at a temperature of 0℃ for 24 hours.

[0161] Comparative Example 4

[0162] Based on the content disclosed in Example 1, the following modifications are made:

[0163] The bromination reaction (the reaction to synthesize brominated polystyrene) was carried out at a temperature of 0°C for 24 hours.

[0164] Comparative Example 5

[0165] Based on the content disclosed in Example 1, the following modifications are made:

[0166] The bromination reaction (the reaction for synthesizing brominated polystyrene) was carried out at a temperature of 40°C for 6 hours.

[0167] The molecular weight and bromine content of the brominated polystyrene products obtained in each example and comparative example were determined, and the results are shown in Table 1.

[0168] Table 1 shows the molecular weight and bromine content of the brominated polystyrene products obtained in each example and comparative example.

[0169]

[0170] As shown in Table 1, the present application provides a method for preparing brominated polystyrene from styrene bromine. This method controls the process of polymerization and bromination to effectively regulate the molecular weight of brominated polystyrene. The molecular weight of the brominated polystyrene product obtained is 3,000 to 630,000, and the weight content of bromine in the brominated polystyrene product is 65% to 70%.

[0171] Furthermore, Comparative Examples 2 and 3 show that changes in reaction temperature at different stages can regulate the molecular weight of brominated polystyrene products. However, excessively low bromination reaction temperatures directly affect the molecular weight of brominated polystyrene products, while excessively low synthesis reaction temperatures directly affect the bromine content by weight. In addition, the bromine content in Comparative Examples 1-3 is below 65% by weight, and these brominated polystyrene products are generally considered substandard. While Comparative Examples 4 and 5 yielded qualified brominated polystyrene products, their molecular weights were low, making it difficult to meet downstream application requirements.

[0172] In summary, the present application provides a method for preparing brominated polystyrene from styrene bromine. This method first controls the process of polymerization to regulate the molecular weight of polystyrene, and then controls the process of bromination to regulate the molecular weight of brominated polystyrene, thereby improving the controllability of the molecular weight of brominated polystyrene.

[0173] In addition, the embodiments of this application provide a system for preparing brominated polystyrene from styrene bromine. The total annual operating time of the system is 7200h to 8400h, and the operating flexibility of the system is 50% to 110%.

[0174] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed in this application.

Claims

1. A method for preparing brominated polystyrene from styrene bromine, the method comprising: Styrene and a first solvent are mixed, and then the mixture is purified using a refining agent to obtain styrene raw material; The styrene raw material is polymerized using an initiator, and then the polymerization reaction is stopped using a stopper to obtain crude polystyrene. The crude polystyrene product was washed with detergent, and then the washed crude polymer product was vacuum dried and pulverized to obtain polystyrene granules. The second solvent, catalyst, bromine source and the polystyrene particles are subjected to a bromination reaction to obtain crude brominated polystyrene. The crude brominated polystyrene was purified to obtain the brominated polystyrene product. The bromination reaction is carried out at a temperature ≤30℃ and for a time ≥8h.

2. The method according to claim 1, wherein the temperature of the bromination reaction is 3℃~30℃, and the time of the bromination reaction is 8h~16h.

3. The method according to claim 1, wherein the weight m1 of the catalyst, the weight m2 of the bromine source, and the weight m3 of the polystyrene particles satisfy the relationship: m1:m2:m3=(0.04~0.17):(1.9~5.1):1; and / or The weights m4 of the initiator, m5 of the terminating agent, and m6 of the styrene raw material satisfy the following relationship: m4:m5:m6=(0.14~0.6):(0.02~0.4):

1.

4. The method according to claim 1, wherein the polymerization reaction temperature is 70℃~110℃ and the polymerization reaction time is 40min~120min.

5. The method according to claim 1, wherein the bromine source comprises bromine chloride, and the method for preparing the bromine chloride comprises: A chlorine source and a bromine source are reacted to produce bromine chloride.

6. The method according to claim 5, wherein the temperature of the synthesis reaction is -25℃ to -5℃, and the time of the synthesis reaction is 8h to 16h.

7. The method according to claim 1, wherein the refining agent comprises at least one of the following: Deoxidizers, molecular sieves, and desulfurizers; and / or The initiator includes at least one of the following types: n-Butyllithium, sec-Butyllithium, and ammonium persulfate; and / or The type of terminating agent includes at least one of the following: Dodecyl mercaptan, ethanol hydrochloride, and isopropanol; and / or The detergent includes deionized water and / or sodium sulfite.

8. The method according to claim 1, wherein the first solvent comprises cyclohexane; and / or The second solvent includes dichloromethane.

9. A system for preparing brominated polystyrene from styrene bromine, said system being adapted to the method of any one of claims 1 to 8, said system comprising: The polystyrene preparation unit includes a styrene refining tank (1), a cyclohexane refining tank (2), a polymerization reactor (3), an initiator pipeline (101), a stop agent pipeline (102), a coagulation reactor (4), and a polystyrene vacuum drying device (5). The polymerization reactor (3) is provided with multiple auxiliary material inlets and multiple raw material inlets. The initiator pipeline (101) and the stop agent pipeline (102) are respectively connected to the auxiliary material inlets of the polymerization reactor (3). The outlets of the styrene refining tank (1) and the cyclohexane refining tank (2) are connected to the inlet of the polymerization reactor (3). The outlet of the polymerization reactor (3) is connected to the inlet of the coagulation reactor (4), and the outlet of the coagulation reactor (4) is connected to the inlet of the polystyrene vacuum drying device (5). The bromine source preparation unit includes a liquid chlorine pipeline (103), a liquid chlorine vaporizer (6), a liquid bromine pipeline (104), a cooling water pipeline (105), and a bromine chloride synthesis reactor (7). The liquid chlorine pipeline (103) is connected to the inlet of the liquid chlorine vaporizer (6), the outlet of the liquid chlorine vaporizer (6) is connected to the air inlet of the bromine chloride synthesis reactor (7), and the liquid bromine pipeline (104) and the cooling water pipeline (105) are respectively connected to the liquid inlet of the bromine chloride synthesis reactor (7). The brominated polystyrene preparation unit includes a dichloromethane pipeline (106), a catalyst pipeline (107), and a bromination reactor (8). The outlet of the bromine chloride synthesis reactor (7) is connected to the inlet of the bromination reactor (8), the outlet of the dichloromethane pipeline (106) is connected to the liquid inlet of the bromination reactor (8), and the outlet of the catalyst pipeline (107) is connected to the inlet of the bromination reactor (8). A post-processing unit is connected to the outlet of the bromination reactor (8).

10. The system according to claim 9, characterized in that, The post-processing unit includes a washing section, a flash crystallization section, and a drying and granulation section. The washing section includes: a first demineralized water pipe (108), a sodium sulfite pipe (109), a first washing vessel (9), a second washing vessel (10), and a third washing vessel (11). The inlet of the first washing vessel (9) is connected to the outlet of the bromination vessel (8). The inlet of the second washing vessel (10) is connected to the outlet of the first washing vessel (9). The inlet of the third washing vessel (11) is connected to the outlet of the second washing vessel (10). The first demineralized water pipe (108) is connected to the first washing vessel (9), the second washing vessel (10), and the third washing vessel (11). The sodium sulfite pipe (109) is connected to the second washing vessel (10). The flash crystallization section includes a second demineralized water pipe (110), an acid-base adjustment pipe (111), a flash evaporator (12), and a centrifuge (13). The outlets of the second demineralized water pipe (110) and the acid-base adjustment pipe (111) are respectively connected to the inlet of the flash evaporator (12). The inlet of the flash evaporator (12) is connected to the outlet of the third washing vessel (11). The outlet of the flash evaporator (12) is connected to the inlet of the centrifuge (13). The drying and granulation section includes a dryer (14) and an extrusion granulator (15). The feed inlet of the dryer (14) is connected to the discharge outlet of the centrifuge (13), and the discharge outlet of the dryer (14) is connected to the feed inlet of the extrusion granulator (15).

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