Composite polymerization inhibitor of 2-bromo-3, 3, 3-trifluoropropene fire extinguishing agent and application of composite polymerization inhibitor

Abstract

The invention belongs to the technical field of polymerization inhibitors, and discloses a composite polymerization inhibitor of a 2-bromo-3, 3, 3-trifluoropropene fire extinguishing agent and application of the composite polymerization inhibitor. Specifically, the composite polymerization inhibitor is selected from one or a combination of more than two of an amine compound, a phenolic compound, a quinone compound, a free radical trapping agent and an auxiliary reducing agent. Furthermore, the composite polymerization inhibitor comprises the following components in parts by mole: 0.5-3 parts of an amine compound, 0.5-2 parts of a phenolic compound and 0.2-1 part of a free radical trapping agent, or 1-3 parts of an amine compound, 0.5-2 parts of a quinone compound and 0.1-0.5 part of an auxiliary reducing agent. According to the polymerization inhibitor, the stability of 2-BTP is effectively improved, degradation reaction is reduced, the polymerization inhibitor can be used for storage and transportation of a 2-BTP fire extinguishing agent, the storage duration of the 2-BTP fire extinguishing agent is prolonged, and the fire extinguishing capacity is guaranteed to a certain degree.

Description

Technical Field

[0001] This invention relates to the field of polymerization inhibitor technology, and more specifically to a composite polymerization inhibitor for 2-bromo-3,3,3-trifluoropropylene fire extinguishing agent and its application. Background Technology

[0002] 2-Bromo-3,3,3-trifluoropropene, or 2-BTP for short, is a novel fire extinguishing agent and a potential alternative to halogenated hydrocarbon fire extinguishing agents. Its most significant advantage is its excellent fire extinguishing performance, which can quickly extinguish fires by inhibiting the free radical chain reaction of flames. 2-BTP has an ODP of approximately 0.0028 and a GWP of less than 5. Although not completely zero, its impact on ozone layer depletion and global warming is negligible compared to traditional chlorine- or bromine-containing fire extinguishing agents, making it a more environmentally friendly choice under current international trends.

[0003] The BTP molecule contains active carbon-carbon double bonds, and the C=C bonds may degrade during storage. In humid and hot environments, these double bonds readily react with water or oxygen to produce bromools and keto acids as byproducts, reducing the purity of the extinguishing active ingredient. Long-term storage can also lead to intermolecular polymerization of the C=C bonds, forming high-molecular-weight polymers, resulting in increased viscosity, decreased atomization performance, and even nozzle clogging. These oxidation, hydrolysis, and spontaneous polymerization reactions all reduce the shelf life and extinguishing capacity of 2-BTP.

[0004] Therefore, developing composite polymerization inhibitors that can improve the stability of 2-bromo-3,3,3-trifluoropropylene is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a variety of composite polymerization inhibitors that improve the stability of 2-bromo-3,3,3-trifluoropropylene. The polymerization inhibitors of the present invention effectively improve the stability of 2-BTP, reduce degradation reactions, and can be used for the storage and transportation of 2-BTP fire extinguishing agents, thereby extending their storage time and ensuring fire extinguishing capability to a certain extent.

[0006] One objective of this invention is to provide a composite polymerization inhibitor for 2-bromo-3,3,3-trifluoropropylene fire extinguishing agent, wherein the composite polymerization inhibitor is selected from one or more combinations of amine compounds, phenolic compounds, quinone compounds, free radical scavengers, and auxiliary reducing agents.

[0007] Furthermore, the composite polymerization inhibitor is a combination of at least one of amine compounds, phenolic compounds, and free radical scavengers;

[0008] Preferably, the composition of the composite polymerization inhibitor, in molar parts, is as follows:

[0009] Amine compounds 0.5–3 parts, phenolic compounds 0.5–2 parts, free radical scavengers 0.2–1 parts.

[0010] More preferably, the composition of the composite polymerization inhibitor, in molar parts, is as follows:

[0011] When the amount of amine compounds is 0.5–3 parts and the amount of phenolic compounds is 0.5–2 parts, the amount of free radical scavenger can be 0 parts.

[0012] Furthermore, the composite polymerization inhibitor includes amine compounds, quinone compounds, and auxiliary reducing agents;

[0013] The composite polymerization inhibitor has the following composition in molar parts:

[0014] 1–3 parts of amine compounds, 0.5–2 parts of quinone compounds, and 0.1–0.5 parts of auxiliary reducing agent.

[0015] Preferably, the amine compound includes at least one of triethylamine, triisopropylamine, and perfluorotriethylamine.

[0016] The polymerization inhibition mechanism of amine compounds:

[0017] In an acidic environment, the C-Br bond breaks faster, promoting the generation of bromine free radicals and producing acidic substances such as HBr. The basic groups of amines can neutralize HBr, avoiding the "acidic autocatalysis" caused by the decrease in system pH and capturing active free radicals: amines have a certain reducing property and can directly combine with the bromine free radicals generated by the decomposition of 2-BTP to form stable amine free radical derivatives, interrupting the initial step of the free radical chain reaction.

[0018] Preferably, the phenolic compound includes at least one of the following: p-tert-butylcatechol (TBC), 2,6-di-tert-butyl-p-cresol (BHT), 2,4-dimethyl-6-tert-butylphenol, 3-methyl-6-tert-butylphenol, 2,6-di-tert-butyl-p-ethphenol, hydroxyanisole (MEHQ), hydroquinone (HQ), 2-methylhydroquinone (THQ), and antioxidant 1010 (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]).

[0019] The polymerization inhibition mechanism of phenolic compounds:

[0020] The phenolic hydroxyl group in the molecule can provide an active hydrogen atom, which can combine with bromine radicals or polymeric reactive radicals generated by the decomposition of 2-BTP to form stable HBr or saturated molecules, directly terminating chain growth. Phenolic molecules that lose hydrogen atoms transform into aryloxy radicals, which are highly stable due to the conjugation effect of the benzene ring and can further capture other reactive radicals to form inert products, thereby blocking chain propagation. The tert-butyl group at the ortho position in the phenolic molecule prevents free radicals from approaching the phenolic hydroxyl group, prolonging the polymerization inhibition period at high temperatures.

[0021] Preferably, the quinone compound includes at least one of p-benzoquinone (PBQ), tetrachlorobenzoquinone (TCBQ), pentafluorobenzoquinone (PFBQ), and 2,6-di-tert-butyl-4-benzylidenecyclohexadienone (QM-PH).

[0022] The polymerization inhibition mechanism of quinone compounds:

[0023] Quinones are "the main force in charge-transfer radical scavenging." The quinone ring in quinone molecules has strong electrophilicity and can combine with active free radicals of 2-BTP, such as bromine radicals and carbon radicals, through charge transfer to form a semiquinone radical. This radical is highly stable and can further combine with other free radicals to form an inert dimer, terminating chain propagation. Quinones can also undergo disproportionation reactions with active free radicals, directly consuming the free radical and converting it into its reduced state, continuously blocking the chain reaction. The electron-withdrawing effect of chlorine or fluorine atoms enhances the electrophilicity of the quinone ring, and compared with non-halogenated quinones, its binding rate with electron-rich bromine radicals is increased by 20% to 30%.

[0024] Preferably, the free radical scavenger includes at least one of 2,2,6,6-tetramethylpiperidine oxide (TEMPO), antioxidant 1010, and lipoic acid.

[0025] The polymerization inhibition mechanism of free radical scavengers:

[0026] Stable radicals can directly terminate the free radical chain. For example, TEMPO, as a stable free radical, can directly covalently bind with the reactive free radical of 2-BTP to form an inactive covalent compound, without relying on hydrogen atom transfer. This method remains effective even in oxygen-deficient or low-hydrogen environments. Addition-type trapping, such as with lipoic acid, involves the thiol group in lipoic acid reacting with reactive free radicals to form stable thioether compounds, directly blocking the extension of the free radical chain.

[0027] Among them, antioxidant 1010 is both a typical phenolic compound and a highly efficient free radical scavenger. When antioxidant 1010 is selected as the phenolic compound in the composition of the composite polymerization inhibitor, the amount of free radical scavenger can be 0.

[0028] In a further preferred embodiment, when antioxidant 1010 is selected as the phenolic compound in the composite polymerization inhibitor composition, it can be used as the main phenolic compound at a molar ratio of 1-1.8 parts to cover the main function of phenolic compounds and has some free radical scavenging function; it can be used as the secondary phenolic compound at a molar ratio of 0.5-1 parts to supplement the free radical scavenging ability.

[0029] Preferably, the auxiliary reducing agent includes at least one of antioxidant 1330 (tris(2,4-di-tert-butylphenyl) phosphite), vitamin C, and epoxide.

[0030] The polymerization inhibition mechanism of auxiliary reducing agents:

[0031] The auxiliary reducing agent enhances system stability through a "reducive regeneration-direct quenching" mechanism. Quinones, after capturing free radicals, are reduced to phenols. The auxiliary reducing agent can re-oxidize phenols back to quinones through its own oxidation, restoring its free radical-capturing activity and extending the polymer inhibitor's lifespan. The reducing groups of the auxiliary reducing agent can directly combine with bromine free radicals to generate stable reduction products, replenishing uncaptured quinone free radicals and reducing the probability of chain reactions. The auxiliary reducing agent preferentially reacts with oxygen, reducing the reaction between oxygen and C=C bonds, avoiding the formation of byproducts such as bromools, and indirectly inhibiting the oxidative decomposition of 2-BTP.

[0032] A second objective of this invention is to provide an application of the aforementioned composite polymerization inhibitor in the storage and transportation of 2-bromo-3,3,3-trifluoropropylene fire extinguishing agent.

[0033] The third objective of this invention is to provide a general preparation process for the composite polymerization inhibitor, the key points of which are:

[0034] 1) Inert environment: All formulations must be prepared under nitrogen or argon protection, with an oxygen content ≤50ppm;

[0035] 2) Temperature control: The temperature of the system containing phenolic components should be ≤60℃, and the temperature of the system containing quinone components should be ≤80℃;

[0036] 3) pH adjustment: The pH of the system is controlled at 8.0~10.5 by using amine components to avoid excessive alkalinity that promotes the hydrolysis of 2-BTP.

[0037] 4) Purity requirements: The purity of the free radical scavenging component is ≥99%, and the moisture content of the amine component is ≤0.1%.

[0038] As can be seen from the above technical solution, compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0039] (1) The composite polymerization inhibitor of the present invention includes amine compounds, phenolic compounds and free radical scavengers, which effectively prevent the decomposition of 2-BTP by covering the entire pathway of acid catalysis, free radical chain initiation and chain growth through triple blocking:

[0040] Amines neutralize acidic substances, eliminate the accelerated breakage of C-Br bonds in 2-BTP caused by pH decrease, and provide a stable reaction environment for phenols and free radical scavengers;

[0041] Phenolic compounds preferentially capture highly reactive bromine radicals, reducing the chain polymerization they initiate. The remaining less reactive radicals are captured by TEMPO or lipoic acid, covering radicals with different activities.

[0042] The steric hindrance effect of phenols synergistically works with the alkaline environment of amines to delay the oxidative failure of the polymerization inhibitor itself and prolong the polymerization inhibition period. Free radical scavengers compensate for the deficiencies of the first two types of components through targeted mechanisms.

[0043] (2) The composite polymerization inhibitor of the present invention includes amine compounds, quinone compounds and auxiliary reducing agents. The electrophilicity of quinones decreases in acidic environments, and amines neutralize acidic substances, which can prevent quinones from becoming ineffective due to protonation. At the same time, the free radical scavenging activity of quinones is enhanced through charge transfer.

[0044] Quinones efficiently capture highly reactive free radicals, while auxiliary reducing agents remove less reactive free radicals and regenerate quinones, forming a "capture-regeneration" cycle that significantly prolongs the polymerization inhibition period;

[0045] The antioxidant effect of the auxiliary reducing agent works synergistically with the alkaline environment of amines to reduce the byproducts generated by the oxidation and hydrolysis of 2-BTP, thereby indirectly reducing the catalytic effect of these byproducts on the polymerization reaction. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0047] Figure 1 The graph shows the decomposition curves of 2-BTP under different times, temperatures, and impurities.

[0048] Figure 2 The decomposition rate curves of 2-BTP at different temperatures are shown.

[0049] Figure 3 The most likely unimolecular decomposition pathway and products of 2-BTP.

[0050] Figure 4 The chromatogram is for 2-BTP + triethylamine-60d.

[0051] Figure 5 The chromatogram is for 2-BTP + triisopropylamine-60d.

[0052] Figure 6 The chromatogram is for 2-BTP + lipoic acid-60d.

[0053] Figure 7 The chromatogram is for 2-BTP+Vitamin C-60d.

[0054] Figure 8 The chromatogram is for 2-BTP + epoxide-60d.

[0055] Figure 9 A process flow diagram for preparing composite polymerization inhibitors. Detailed Implementation

[0056] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0057] Decomposition of 2-BTP without stabilizer

[0058] 1. Self-decomposition

[0059] 2-BTP decomposes naturally in the absence of impurities. The presence of oxygen and water accelerates this decomposition, but high levels of oxygen are not present during storage. Temperature is a more significant factor influencing the decomposition rate of 2-BTP than water and O2. Under the influence of O2, the C=C bonds in 2-BTP break, and it is oxidized to CF3CHBrCHO.

[0060] 2. Rubber Catalysis

[0061] During the storage of 2-BTP, it may corrode the elastic rubber material used for sealing, affecting the sealing effect. Simultaneously, the rubber material may catalyze the decomposition of 2-BTP during contact with it. The catalytic decomposition of 2-BTP by rubber mainly occurs through polymerization, requiring suitable polymerization inhibitors to suppress its decomposition.

[0062] Under the catalysis of rubber, the decomposition products mostly contain long carbon chains. The C-Br bond of 2-BTP may break, generating bromine free radicals. These bromine free radicals catalyze the decomposition reaction of 2-BTP and cause the carbon chains to polymerize.

[0063] EPDM, HNBR, CR, and IIR are four typical rubber materials used for sealing. These four typical rubbers have a significant promoting effect on the decomposition of 2-BTP, especially HNBR rubber, whose catalytic decomposition rate of 2-BTP is close to 60%.

[0064] 3. Catalysis by metallic materials

[0065] During the storage of 2-BTP, corrosion of the metal materials used for storage may occur, affecting the sealing effect. Furthermore, contact between the metal materials and 2-BTP may catalyze its decomposition. This catalytic decomposition of 2-BTP by metals primarily occurs through polymerization, necessitating the use of suitable polymerization inhibitors to suppress its decomposition.

[0066] 37Mn, 20#, 316L, and pure aluminum are four common metals. By analyzing the decomposition rate of 2-BTP after being catalyzed by these four metals, it was found that the metal materials have a significant promoting effect on the decomposition of 2-BTP, and most of the decomposition products contain long carbon chains. The research analysis suggests that these products may be long carbon chain polymers. Under the catalysis of the metals, the C-Br bond of 2-BTP will break, generating bromine free radicals. These bromine free radicals will catalyze the decomposition reaction of 2-BTP and cause the carbon chains to polymerize.

[0067] 4.2-BTP Decomposition Mechanism

[0068] The bond dissociation energies (BDEs) of each chemical bond within the 2-BTP molecule were calculated using Gaussian software. The C-Br bond, with a length of 1.906 Å, is the longest in the 2-BTP molecule, and its dissociation energy is 304.1 kJ / mol, significantly lower than the dissociation energies of other bonds, making it the most easily broken bond in the molecule. Furthermore, the lowest energy barrier (300.1 kJ / mol) for the possible decomposition reaction of 2-BTP was calculated using the TS method, along with the pathway: CF3CBrCH2 → CF3CCH + HBr.

[0069] The decomposition mechanism consists of two parts:

[0070] (1) After the C-Br bond breaks, bromine free radicals are generated. Some of these bromine free radicals will generate liquid bromine, while the other part of the bromine free radicals will continue to exist, thereby triggering a chain decomposition reaction, accelerating the removal of Br, and forming an unstable intermediate C3H3F3. Under the action of bromine free radicals, C3H3F3 undergoes a polymerization reaction to generate a long carbon chain polymer.

[0071] (2) 2-BTP decomposes to produce HBr, and in the presence of acid and free radicals, CF3CCH will undergo a polymerization reaction to generate long carbon chain polymers.

[0072] 5 2-BTP decomposition products

[0073] (1) The most likely unimolecular decomposition pathways and products of 2-BTP, such as Figure 3 As shown.

[0074] (2) The decomposition products of the reaction between 2-BTP and O2 are:

[0075] The reaction equation is:

[0076] Example 1: Polymerization Inhibition Experiment of a Monomer Inhibitor

[0077] 1.1 Nitrogen gas was introduced into the experimental container, pressurized to 6 MPa, and then placed in water. Observation showed that no bubbles were produced, indicating that the reaction container was airtight.

[0078] 1.2 Inhibition Test of 2-BTP Decomposition by Additives: Before the experiment, epoxide, lipoic acid, vitamin C, triisopropylamine, and triethylamine were placed in different reaction vessels, and a sample without additives was also prepared. High-purity 2-BTP was pumped into the reaction vessel using a peristaltic pump. The reaction vessel was placed in a constant temperature and humidity chamber, with the chamber temperature set at 25℃, and the experimental period was 60 days.

[0079] 1.3 Remove the sample after the test: Open the high-pressure reactor and use a brown glass bottle to collect the residual extinguishing agent in the reactor.

[0080] 1.4 Calculation of Sample Decomposition Rate After Experiment: 1 μL of sample was extracted using a micro-syringe during a 60-day experiment at 25°C and injected into a GC-MS sample for analysis. Each sample was analyzed three times. The decomposition rate of the extinguishing agent was calculated, and the average decomposition rate was used to represent the overall decomposition rate of the extinguishing agent.

[0081] Table 1 shows the effect of 2-BTP.

[0082] Experimental conclusions

[0083] All five monomer inhibitors significantly reduced the decomposition rate of 2-BTP. Among them, triethylamine, triisopropylamine, and lipoic acid had a strong inhibitory effect on the decomposition of 2-BTP. Triethylamine had the best effect on improving the stability of 2-BTP, reducing the decomposition rate of 2-BTP by about 90%, while epoxide had the worst effect.

[0084] The polymerization inhibition mechanism of monomer inhibitors is analyzed below.

[0085] 1. Triethylamine

[0086] (1) Inhibition mechanism

[0087] It is speculated that triethylamine enhances the stability of 2-BTP through multiple mechanisms: firstly, its basic nature neutralizes acidic byproducts generated during decomposition, such as HBr, thus preventing autocatalytic decomposition reactions caused by local pH decreases; secondly, triethylamine's strong reducing properties allow it to act as a free radical scavenger, quenching bromine free radicals generated during decomposition, interrupting the free radical chain reaction, and slowing down the decomposition process of 2-BTP. This synergistic effect effectively reduces the risk of breaking key chemical bonds, significantly enhancing the chemical stability of 2-BTP.

[0088] (2) Experimental results

[0089] In a 60-day test at 25°C, triethylamine reduced the 2-BTP decomposition rate to 5.76%, a 74.9% decrease compared to the untreated rate. Chromatography showed a significant reduction in impurity peaks, demonstrating that free radical reactions were inhibited.

[0090] 2. Triisopropylamine

[0091] (1) Inhibition mechanism

[0092] The polymerization inhibition mechanism is similar to that of triethylamine, but the tert-butyl structure provides greater steric hindrance, delaying its self-oxidative failure. Neutralizing HBr reduces the generation of bromine free radicals; simultaneously, it directly binds to active free radicals, forming inert products.

[0093] (2) Experimental results

[0094] During the 60-day test, the decomposition rate decreased to 5.76%, a reduction of 74.9%. The chromatogram showed low impurity peaks, indicating that both acid catalysis and free radical reactions were inhibited.

[0095] 3. Alpha-lipoic acid

[0096] (1) Inhibition mechanism

[0097] Lipoic acid contains a thiol group, which can undergo addition reactions with active free radicals, such as bromine radicals or carbon radicals, to form stable thioether compounds, directly terminating chain growth.

[0098] (2) Experimental results

[0099] With the addition of lipoic acid, the 2-BTP decomposition rate was 6.3% and the decrease rate was 72.5% in a 60-day test at 25°C. The chromatogram showed a sharp main peak and weak impurity peaks, verifying that free radicals were efficiently captured.

[0100] 4. Vitamin C

[0101] (1) Inhibition mechanism

[0102] Vitamin C combines with bromine free radicals to produce stable products such as dehydroascorbic acid. It preferentially reacts with oxygen, reducing 2-BTP oxidation byproducts.

[0103] (2) Experimental results

[0104] With the addition of vitamin C, the 2-BTP decomposition rate decreased to 8.4% in a 60-day test at 25°C, a reduction rate of 63.4%. Chromatographic comparison with the sample without the additive showed a reduction in oxidation products.

[0105] 5. Butane oxide

[0106] (1) Inhibition mechanism

[0107] Butylene oxide preferentially reacts with oxygen, consuming O2 in the environment, reducing the production of byproducts such as CF3CHBrCHO from the oxidation of 2-BTP, directly quenching low-activity free radicals, and forming stable ether compounds through ring-opening reactions.

[0108] (2) Experimental results

[0109] When epoxide acts alone, in a 60-day test at 25°C, the decomposition rate of 2-BTP decreased to 14.15%, a reduction rate of 38%. The effect is relatively weak, but the chromatogram shows that the main peak is well preserved, making it suitable as an auxiliary component.

[0110] The polymerization inhibition mechanism of the other monomer polymerization inhibitors in this invention is as follows:

[0111] 6. Perfluorotriethylamine

[0112] Effective fire extinguishing agents and stabilizing agents

[0113] 7. p-tert-Butylcatechol (TBC)

[0114] p-tert-butylcatechol, abbreviated as TBC, can absorb oxygen and be oxidized to form quinone, thus preventing butadiene from being oxidized and generating peroxide radicals. Secondly, the two phenolic hydroxyl groups (-OH) in the TBC molecule can provide active hydrogen atoms, which can combine with the active bromine radicals that initiate polymerization to form stable compounds, directly terminating the chain propagation reaction. After losing hydrogen atoms, TBC forms aryloxy radicals (ArO·), which are stabilized by conjugation and can further capture other active free radicals to form inert products, blocking chain propagation.

[0115] p-tert-butylcatechol is deactivated at 60°C, making it suitable for room temperature storage and high-temperature polymerization systems.

[0116] 8. 2,6-Di-tert-butyl-p-cresol (BHT)

[0117] In 2,6-di-tert-butyl-p-cresol (BHT), the sterically hindered tert-butyl group at the ortho position prevents free radicals from approaching, thus prolonging the polymerization inhibition period.

[0118] 9. 2,4-Dimethyl-6-tert-butylphenol

[0119] In 2,4-dimethyl-6-tert-butylphenol, the hydroxyl group provides a hydrogen atom to capture bromine radicals, generating stable phenoxy radicals that terminate the chain growth reaction. The steric hindrance effect of the tert-butyl and ortho-methyl groups enhances thermal stability, remaining effective at 80–120°C, making it suitable for the storage and transportation of 2-BTP.

[0120] 10. 4-Methyl-6-tert-butylphenol

[0121] 4-Methyl-6-tert-butylphenol, in comparison, has a lower polymerization inhibition efficiency due to the limited activity of the phenolic hydroxyl group by the monosubstituted methyl group.

[0122] 11. 2,6-Di-tert-butyl-p-acetol

[0123] 2,6-Di-tert-butyl-p-acetol captures free radicals through its phenolic hydroxyl group, while the steric hindrance of the tert-butyl group delays the oxidation chain reaction. It plays an inhibitory role in polymerization by converting to a quinone structure with the help of dissolved oxygen.

[0124] 12. Hydroxyanisole (MEHQ)

[0125] Hydroxyanisole (MEHQ), in the presence of oxygen, is oxidized to quinone compounds, which then react with bromine radicals to form stable ether bonds or semiquinone structures, terminating chain growth. It exhibits poor stability at high temperatures, failing above 80°C, and is best stored at room temperature.

[0126] 13. Hydroquinone

[0127] Hydroquinone, under aerobic conditions, is first oxidized to p-benzoquinone. The bromine radicals generated during the polymerization of 2-BTP then undergo an addition reaction, producing a stable, inactive product, thus terminating the polymerization reaction. Its polymerization inhibition effect is significant, especially at room temperature. However, it relies on oxygen to function; its inhibition efficiency decreases in anaerobic environments. It may decompose at high temperatures, affecting its effectiveness. Therefore, it is suitable for the room-temperature transportation and storage of 2-BTP, or for inhibiting low-temperature polymerization reactions.

[0128] 14. p-Benzoquinone (PBQ)

[0129] p-Benzoquinone, abbreviated as PBQ, is soluble in a variety of organic solvents and can still function under anaerobic conditions. It directly undergoes addition or disproportionation reactions with chain radicals to generate quinone or semiquinone radicals, which then combine with other radicals to form stable molecules without the need for oxygen. Even in anaerobic environments, such as sealed systems, it still exhibits a high inhibition effect on polymerization. It can be used for the storage or transportation of 2-BTP in sealed, anaerobic environments.

[0130] 15. Tetrachlorobenzoquinone (TCBQ)

[0131] Tetrachlorobenzoquinone (TCBQ) exhibits enhanced reactivity due to the electron-withdrawing effect of its chlorine atom, resulting in a faster reaction with free radicals and higher polymerization inhibition efficiency. It is suitable for inhibiting the polymerization of highly reactive monomers; its inhibitory effect on high-temperature polymerization systems is superior to that of ordinary quinones. Therefore, it is suitable for inhibiting the polymerization of 2-BTP under high temperature or high free radical concentration conditions. However, TCBQ has relatively high toxicity, and precautions must be taken during handling.

[0132] 16. Pentafluorobenzoquinone (PFBQ)

[0133] Pentafluorobenzoquinone (PFBQ) undergoes a quinone ring addition reaction with the bromine radical of 2-BTP to generate a semiquinone radical, which then combines with another radical to form a stable product. Simultaneously, the strong electron-withdrawing effect of the pentafluoro substituent significantly enhances the electrophilicity of the quinone ring, making it more effective at capturing electron-rich radicals. It is effective at temperatures ranging from room temperature to 120°C and is suitable for storage with 2-BTP.

[0134] 17. 2-Methylhydroquinone (THQ)

[0135] 2-Methylhydroquinone, abbreviated as THQ, enhances electron donation ability, accelerates the formation of quinone intermediates, captures free radicals through addition reactions, and has significant polymerization inhibition efficiency at high temperatures.

[0136] 18. 2,6-Di-tert-butyl-4-benzylidenecyclohexadienone (QM-PH)

[0137] 2,6-Di-tert-butyl-4-benzylidenecyclohexadienone, abbreviated as QM-PH, has a strong electrophilic quinone ring that efficiently binds to the bromine radical of 2-BTP, blocking chain growth and making it suitable for high-temperature applications.

[0138] 19. 2,2,6,6-Tetramethylpiperidine oxide (TEMPO)

[0139] 2,2,6,6-Tetramethylpiperidine oxide (TEMPO) is a stable free radical that directly combines with chain free radicals to form covalent bonds, generating inactive compounds, thereby terminating the polymerization reaction. It belongs to the active free radical type of polymerization inhibitor. It has high polymerization inhibition efficiency and can function under mild conditions, such as room temperature, aerobic or anaerobic environments. It can also produce synergistic effects when compounded with other polymerization inhibitors.

[0140] 20. Antioxidant 1010 (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate])

[0141] Antioxidant 1010 captures free radicals through a hydrogen atom transfer mechanism and has a certain inhibitory effect on 2-BTP bromine radicals (Br). It needs to be combined with auxiliary inhibitors such as TEMPO to improve efficiency.

[0142] 21. Antioxidant 1330 (tris(2,4-di-tert-butylphenyl)phosphite)

[0143] Antioxidant 1330 may indirectly assist in polymerization inhibition during high-temperature processing by decomposing peroxides, but it still needs to be combined with phenols or TEMPO to improve efficiency.

[0144] Example 2 provides a composite polymerization inhibitor

[0145] (1) Formulation: Select lipoic acid + triisopropylamine + triethylamine + TBC compound

[0146] (2) Raw material ratio (molar parts)

[0147] Thioctic acid: 0.5 parts, triisopropylamine: 1 part, triethylamine: 2.5 parts, TBC: 1 part

[0148] (3) Preparation process

[0149] Raw material pretreatment: Thioctic acid, triisopropylamine, triethylamine, and TBC are dried to remove water (water content ≤50 ppm).

[0150] Inert environment: The stainless steel reactor is purged with nitrogen three times (O2≤50 ppm).

[0151] Component dissolution and mixing: Add TBC to a stainless steel reactor, heat to 40°C, and mechanically stir (300 rpm) until completely dissolved. Then add triisopropylamine and triethylamine in sequence, maintain 40°C and stir for 20 minutes. Then slowly add thioctic acid dropwise, heat to 60°C and continue stirring for 1 hour (temperature and time control) to obtain a transparent yellow solution that can be used directly without purification.

[0152] Example 3 provides a composite polymerization inhibitor

[0153] (1) Compound formulation: Select BHT + TEMPO + triethylamine compound

[0154] (2) Raw material ratio (molar parts)

[0155] BHT: 1.2 parts, TEMPO: 0.6 parts, triethylamine: 1.5 parts

[0156] (3) Preparation process

[0157] BHT, TEMPO, and triethylamine were dried (vacuum drying at 60℃ for 2 h). The reaction system was protected by nitrogen. BHT and TEMPO were co-dissolved in ethanol solvent (10 wt%). Triethylamine was added dropwise, and the mixture was magnetically stirred at 25℃ for 2 hours. Ethanol was removed by vacuum distillation (purification treatment) to obtain a white waxy solid.

[0158] Example 4 provides a composite polymerization inhibitor

[0159] (1) Composite formulation: Perfluorotriethylamine + MEHQ + Antioxidant 1010

[0160] (2) Raw material ratio (molar parts)

[0161] Perfluorotriethylamine: 1 part, Hydroxyanisole (MEHQ): 0.8 parts, Antioxidant 1010: 0.5 parts

[0162] (3) Preparation process

[0163] The experimental materials were dried, and MEHQ and antioxidant 1010 were added to a glass reactor. The mixture was heated to 50°C under nitrogen protection and stirred until dissolved (200 rpm). Perfluorotriethylamine was slowly added dropwise while stirring at 50°C for 1.5 hours. The mixture was then cooled to 25°C to obtain a colorless and transparent solution. During the preparation process, MEHQ must be handled in the dark to prevent oxidation; the system was strictly deoxygenated by bubbling with nitrogen for 10 minutes.

[0164] Example 5 provides a composite polymerization inhibitor

[0165] (1) Composite formulation: Triethylamine + 2,4-dimethyl-6-tert-butylphenol + thioctic acid composite.

[0166] (2) Raw material ratio (molar parts)

[0167] Triethylamine: 2 parts, 2,4-dimethyl-6-tert-butylphenol: 1.5 parts, lipoic acid: 0.4 parts

[0168] (3) Preparation process

[0169] The raw materials were dried, and nitrogen was used to cover the liquid surface. 2,4-Dimethyl-6-tert-butylphenol was dissolved in acetone (15 wt%), and triethylamine was added. The mixture was magnetically stirred at 25°C for 1 hour. Lipoic acid was added dropwise, and the temperature was raised to 55°C and stirred for 2 hours to obtain a light yellow viscous liquid. The dropwise addition rate of lipoic acid should be ≤0.5 mL / min to avoid local overheating. Acetone needs to be recovered by vacuum distillation (60°C / 10 kPa).

[0170] Example 6 provides a composite polymerization inhibitor

[0171] (1) Compound formulation: PFBQ + triisopropylamine + antioxidant 1330 compound.

[0172] (2) Raw material ratio

[0173] PFBQ: 1 part, Triisopropylamine: 2 parts, Antioxidant 1330: 0.2 parts

[0174] (3) Preparation process

[0175] The raw materials were dried, and triisopropylamine and PFBQ were mixed under light-protected conditions. The temperature was controlled at 0-5℃ and stirred for 30 minutes. Antioxidant 1330 was added, and the temperature was raised to 25℃ and stirred for 4 hours to obtain a blue-green suspension. The suspension was filtered through a 0.22 μm filter membrane and the filtrate was collected.

[0176] Example 7 provides a composite polymerization inhibitor

[0177] (1) Compound formula: PBQ + triethylamine + vitamin C compound

[0178] (2) Raw material ratio (molar parts):

[0179] PBQ: 1.2 parts, Triethylamine: 1.5 parts, Vitamin C: 0.3 parts

[0180] (3) Preparation process

[0181] After pulverizing vitamin C, it was dried under vacuum in the dark. PBQ and triethylamine were mixed in a brown reaction flask, and stirred in an ice-water bath (0°C) for 20 minutes in the dark. Vitamin C was added, and the mixture was heated to 25°C and stirred for 5 hours. The insoluble matter was removed by filtration to obtain a reddish-brown solution.

[0182] Example 8 provides a composite polymerization inhibitor

[0183] (1) Composite formulation: TCBQ + perfluorotriethylamine + antioxidant 1330 composite.

[0184] (2) Raw material ratio (molar parts)

[0185] TCBQ: 0.8 parts, perfluorotriethylamine: 2.5 parts, antioxidant 1330: 0.4 parts

[0186] (3) Preparation process

[0187] The raw materials were dried, and the process was carried out in a fume hood while wearing respirators and corrosion-resistant gloves (inert environment construction). Perfluorotriethylamine and TCBQ were mixed in a fluorocarbon solvent (Novec 7100, 10 wt%) and sonicated at -10°C for 15 minutes. Antioxidant 1330 was added, and the mixture was heated to 20°C and stirred for 6 hours. The mixture was then filtered through a 0.45 μm filter membrane to obtain a green suspension. The entire preparation process must be carried out at a temperature ≤25°C to prevent TCBQ decomposition.

[0188] Example 9 provides a composite polymerization inhibitor

[0189] (1) Composite formulation: QM-PH + triisopropylamine + epoxide composite is selected.

[0190] (2) Raw material ratio (molar parts)

[0191] QM-PH: 1.5 parts, triisopropylamine: 2.2 parts, epoxide: 0.5 parts

[0192] (3) Preparation process

[0193] The raw material was dried, QM-PH was dissolved in toluene (15 wt%), triisopropylamine was added under nitrogen protection, epoxide was added at a dropping rate ≤1 mL / min, and the mixture was stirred at 50°C for 1 hour; epoxide was added slowly, and the mixture was stirred at 50°C for 3 hours; toluene was removed by vacuum distillation to obtain a yellow oily substance.

[0194] Effect tests were conducted on the composite polymerization inhibitors of Examples 2-9.

[0195] Self-decomposition test

[0196] 1. Test Plan

[0197] 1) Test for airtightness of experimental containers:

[0198] Nitrogen gas was introduced into the experimental container, pressurized to 6 MPa, and then placed in water. Observe whether bubbles are generated. If no bubbles are generated, the reaction container is considered to be airtight; if bubbles are generated, the reaction container is considered to be leaking, and leak detection and leak prevention measures are taken until the reaction container no longer leaks.

[0199] 2) Inhibition test of stabilizing agent on 2-BTP decomposition:

[0200] The initial concentration of 2-BTP was measured using GC-MS before the experiment. Eight example polymerization inhibitors were placed in reaction vessels before the experiment, which was conducted at 25°C for 60 days.

[0201] 2 Experimental Procedure

[0202] 1) Nitrogen gas was introduced into the experimental container, pressurized to 6 MPa, and then placed in water. No bubbles were observed, indicating that the reaction container was airtight.

[0203] 2) Inhibition test of 2-BTP decomposition by additives: Before the experiment, eight polymerization inhibitors were placed in the reaction vessel, and one sample without additives was reserved. High-purity 2-BTP was pumped into the reaction vessel using a peristaltic pump. The reaction vessel was placed in a constant temperature and humidity chamber, and the temperature of the chamber was set to 25℃. The experimental period was 60 days.

[0204] 3) Remove the sample after the test: Open the high-pressure reactor and use a brown glass bottle to collect the residual extinguishing agent in the reactor.

[0205] 4) Calculation of sample decomposition rate after the test: 1 μL of sample was extracted using a micro-syringe during a 60-day test at 25°C and injected into a GC-MS for analysis. Each sample was analyzed three times. The decomposition rate of the extinguishing agent was calculated, and the average decomposition rate of the extinguishing agent was used to represent the overall decomposition rate of the extinguishing agent.

[0206] The decomposition rates are shown in Table 2.

[0207] Table 2

[0208] The relative decrease rate without adjuvants is shown in Table 3.

[0209] Table 3

[0210] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. 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 the invention. Therefore, the invention 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 disclosed herein.

Claims

1. A composite polymerization inhibitor for 2-bromo-3,3,3-trifluoropropylene fire extinguishing agent, characterized in that, The composite polymerization inhibitor is selected from one or more combinations of amine compounds, phenolic compounds, quinone compounds, free radical scavengers, and auxiliary reducing agents.

2. The composite polymerization inhibitor for 2-bromo-3,3,3-trifluoropropylene fire extinguishing agent according to claim 1, characterized in that, The composite polymerization inhibitor is a combination of at least one of amine compounds, phenolic compounds, and free radical scavengers; The composite polymerization inhibitor has the following composition in molar parts: Amine compounds 0.5–3 parts, phenolic compounds 0.5–2 parts, free radical scavengers 0–1 parts.

3. The composite polymerization inhibitor for 2-bromo-3,3,3-trifluoropropylene fire extinguishing agent according to claim 1, characterized in that, The composite polymerization inhibitor includes amine compounds, quinone compounds, and auxiliary reducing agents; The composite polymerization inhibitor has the following composition in molar parts: 1–3 parts of amine compounds, 0.5–2 parts of quinone compounds, and 0.1–0.5 parts of auxiliary reducing agent.

4. The composite polymerization inhibitor for 2-bromo-3,3,3-trifluoropropylene fire extinguishing agent according to claim 1, characterized in that, The amine compounds include at least one of triethylamine, triisopropylamine, and perfluorotriethylamine.

5. The composite polymerization inhibitor for 2-bromo-3,3,3-trifluoropropylene fire extinguishing agent according to claim 1, characterized in that, The phenolic compounds include at least one of the following: p-tert-butylcatechol, 2,6-di-tert-butyl-p-cresol, 2,4-dimethyl-6-tert-butylphenol, 3-methyl-6-tert-butylphenol, 2,6-di-tert-butyl-p-acetol, hydroxyanisole, hydroquinone, 2-methylhydroquinone, and antioxidant 1010.

6. The composite polymerization inhibitor for 2-bromo-3,3,3-trifluoropropylene fire extinguishing agent according to claim 1, characterized in that, The quinone compounds include at least one of p-benzoquinone, tetrachlorobenzoquinone, pentafluorobenzoquinone, and 2,6-di-tert-butyl-4-benzylidenecyclohexadienone.

7. The composite polymerization inhibitor for 2-bromo-3,3,3-trifluoropropylene fire extinguishing agent according to claim 1, characterized in that, The free radical scavenger includes at least one of 2,2,6,6-tetramethylpiperidine oxide, antioxidant 1010, and lipoic acid.

8. The composite polymerization inhibitor for 2-bromo-3,3,3-trifluoropropylene fire extinguishing agent according to claim 1, characterized in that, The auxiliary reducing agent includes at least one of antioxidant 1330, vitamin C, and epoxide.

9. The use of the composite polymerization inhibitor according to any one of claims 1-8 in the storage and transportation of 2-bromo-3,3,3-trifluoropropylene fire extinguishing agent.

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