Eutectic solvent as well as preparation method and application thereof

Abstract

The invention discloses a eutectic solvent as well as a preparation method and application thereof, and belongs to the technical field of styrene adsorption. The deep eutectic solvent comprises alpha-phenethyl alcohol, acetophenone and methyl triphenyl phosphorus bromide, and the adsorption effect of styrene is improved based on multiple and reversible physical and chemical synergistic effects generated between all components of the solvent and styrene molecules. Strong ion-pi interaction is generated between phosphorus cations of methyltriphenylphosphonium bromide in the solvent and benzene ring electron cloud of styrene to form main adsorption driving force; a benzene ring of acetophenone and a benzene ring of styrene form a pi-pi accumulation effect, so that the capturing capability is further enhanced; meanwhile, a hydrogen bond network formed by hydroxyl of alpha-phenethyl alcohol and two receptors constructs a solvent microenvironment with adjustable polarity and matched space, which is more beneficial to dissolution and enrichment of styrene molecules in thermodynamics. The acting forces synergistically realize high-efficiency and high-selectivity reversible adsorption of styrene.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of styrene adsorption, and particularly relates to a eutectic solvent and a preparation method and application thereof. BACKGROUND

[0002] In the production and storage of styrene and related products in the petrochemical industry, the treatment of volatile organic compounds (VOCs) is one of the core issues of environmental protection and safety production. The tail gas from the overhead of the intermediate tank, product tank and atmospheric storage tank of styrene, propylene oxide / styrene (POSM) and other devices is usually rich in styrene components. According to the VOCs emission standard, such gas must be treated by deep purification before being discharged. However, the unique chemical properties of styrene monomer constitute the main technical obstacle in the treatment process. After condensation, it is easy to self-polymerize to form solid polymers, which block the pipelines, towers and heat exchange equipment, resulting in unplanned shutdown of the device. Therefore, the conventional condensation recovery technology has limited applicability in such scenarios. At present, the commonly used solution in the industry is the absorption process, such as using multi-ethylbenzene residual oil or crude gasoline as the absorbent to contact and absorb the low-concentration styrene waste gas in the packed tower or plate tower. Although this technical route can effectively transfer the gas-phase pollutants, it produces a more intractable "secondary pollution" problem: the rich solvent absorbed with styrene cannot be directly returned to the upstream device for regeneration and reuse due to its complex composition and easy polymerization. This results in a large amount of rich solvent having to be disposed as hazardous waste by entrusting a third party with the necessary qualifications. This process not only generates high hazardous waste treatment costs, increasing the life cycle cost, but also in essence fails to achieve complete resourceization or harmlessness of the pollutants, only transferring the gas-phase pollution to liquid-phase hazardous waste, which deviates from the principles of green chemical industry and circular economy.

[0003] Therefore, it is necessary to develop an efficient, stable and recyclable styrene-specific absorbent to replace the currently disposable organic solvent, which is the key to solving the industry pain points and promoting the upgrading of tail gas treatment technology. SUMMARY

[0004] In order to solve the problems of the prior art, the purpose of the present application is to provide a eutectic solvent (DES) and a preparation method and application thereof. The present application, aiming at the specific structure of styrene molecules, designs the components of the eutectic solvent rationally, and constructs a new eutectic solvent with high absorption capacity, high selectivity and easy regeneration, thereby providing a new technical path for realizing resource recovery and near-zero emission of styrene VOCs.

[0005] In order to achieve the above purpose, the technical scheme of the present application is as follows: The first aspect of the present application provides a eutectic solvent, comprising a hydrogen bond donor and a hydrogen bond acceptor; the hydrogen bond donor is alpha-phenylethanol, and the hydrogen bond acceptor is acetophenone and methyltriphenylphosphonium bromide. The molar ratio of alpha-phenylethanol, acetophenone and methyltriphenylphosphonium bromide is (0.4-0.6):(0.4-0.6):(9-10).

[0006] In some embodiments of the present application, the eutectic solvent further comprises furfural, and the mass of furfural is 1%-5% of the mass of methyltriphenylphosphonium bromide.

[0007] In some embodiments of the present application, the molar ratio of alpha-phenylethanol, acetophenone and methyltriphenylphosphonium bromide is 0.5:0.5:(9-10).

[0008] In some embodiments of the present application, the molar ratio of alpha-phenylethanol, acetophenone and methyltriphenylphosphonium bromide is 0.5:0.5:(9.3-9.8).

[0009] In some embodiments of the present application, the molar ratio of alpha-phenylethanol, acetophenone and methyltriphenylphosphonium bromide is 0.5:0.5:9.5.

[0010] The second aspect of the present application provides a preparation method of the eutectic solvent of the first aspect, comprising: Mixing alpha-phenylethanol, acetophenone and methyltriphenylphosphonium bromide, and reacting under heating and stirring to form a uniform transparent liquid.

[0011] In some embodiments of the present application, the heating temperature of the reaction is 50-80℃.

[0012] In some embodiments of the present application, the heating temperature of the reaction is 60-80℃.

[0013] In some embodiments of the present application, the reaction is carried out under stirring, and after the solid components are completely dissolved and the system forms a uniform transparent liquid, constant temperature stirring is continued for 0.5-2 h.

[0014] The third aspect of the present application provides the use of the eutectic solvent of the first aspect in adsorbing and / or separating styrene in gas phase and / or liquid phase.

[0015] The fourth aspect of the present application provides a method for adsorbing styrene, comprising: Under normal pressure and at 20-60℃, passing a gas containing styrene to be treated into the eutectic solvent of the first aspect, stopping the passing of the gas to be treated after adsorption saturation, and heating the eutectic solvent reaching adsorption saturation to obtain styrene; Or, the liquid to be treated containing styrene is mixed with the eutectic solvent of the first aspect, and the eutectic solvent is distilled to obtain styrene.

[0016] The present application has the following advantages: The eutectic solvent provided by the present application comprises α-phenylethanol, acetophenone and methyltriphenylphosphonium bromide. Based on the multiple and reversible physical and chemical synergies between the components of the solvent and the styrene molecules, the adsorption effect of the styrene is improved. Specifically, the strong ion-π interaction between the phosphonium cation of methyltriphenylphosphonium bromide in the solvent and the electron cloud of the benzene ring of styrene constitutes the main adsorption driving force; the π-π stacking interaction between the benzene ring of acetophenone and the benzene ring of styrene further enhances the capture capacity; at the same time, the hydrogen bond network formed by the hydroxyl group of α-phenylethanol and the two acceptors builds a polar adjustable and space matching solvent microenvironment, which is more thermodynamically beneficial to the dissolution and enrichment of styrene molecules. These forces synergistically achieve high-efficiency and high-selectivity reversible adsorption of styrene.

[0017] The present application also provides a preparation method of the eutectic solvent. The raw materials (α-phenylethanol, acetophenone, methyltriphenylphosphonium bromide, and a small amount of furfural) are blended and heated at a specific ratio under mild conditions in one step, and the process is extremely simple. An intelligent solvent system with dual functional sites of "physical dissolution" and "chemical capture" is directly constructed by one-step method. The introduction of a small amount of furfural successfully forms reversible covalent bonding sites in situ in the solvent without increasing the complexity of preparation and the cost of raw materials. The final product not only inherits the basic advantages of low eutectic solvent such as low vapor pressure and low volatility, but also realizes high capacity and high selectivity capture and easy desorption and regeneration of styrene molecules, thereby solving the fundamental problems of traditional absorbents such as poor selectivity, low capacity, difficult recycling and high disposal cost of hazardous waste, and providing an efficient and green solution for the resource recovery of styrene VOCs. DETAILED DESCRIPTION

[0018] The technical solutions of the present application will be described clearly and completely below in combination with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0019] The present application provides a eutectic solvent, comprising a hydrogen bond donor and a hydrogen bond acceptor; the hydrogen bond donor is α-phenylethanol, and the hydrogen bond acceptor is acetophenone and methyltriphenylphosphonium bromide. The molar ratio of α-phenylethanol, acetophenone and methyltriphenylphosphonium bromide is (0.4-0.6):(0.4-0.6):(9-10).

[0020] The eutectic solvent is a new type of green functional medium, which has great potential in the field of gas separation due to its low vapor pressure, designable structure, simple synthesis and strong renewability. The eutectic solvent provided in the application comprises alpha-phenethyl alcohol, acetophenone and methyltriphenylphosphonium bromide, and based on the multiple and reversible physical and chemical synergies between the components of the solvent and styrene molecules, the adsorption effect of styrene is improved. Specifically, the phosphonium cation of methyltriphenylphosphonium bromide in the solvent produces strong ion-pi interaction with the electron cloud of the benzene ring of styrene, which constitutes the main adsorption driving force; the benzene ring of acetophenone forms pi-pi stacking interaction with the benzene ring of styrene, which further enhances the capture capacity; at the same time, the hydrogen bond network formed by the hydroxyl group of alpha-phenethyl alcohol and the two receptors constructs a polar adjustable and space matching solvent microenvironment, which is more beneficial to the dissolution and enrichment of styrene molecules from the thermodynamic point of view. These forces synergistically realize the efficient and high-selectivity reversible adsorption of styrene.

[0021] In the application, the eutectic solvent further comprises furfural, and the mass of furfural is 1%-5% of the mass of methyltriphenylphosphonium bromide.

[0022] In the application, the eutectic solvent further comprises furfural, and the mass of furfural is 1%-5% of the mass of methyltriphenylphosphonium bromide.

[0023] In the application, the molar ratio of alpha-phenethyl alcohol, acetophenone and methyltriphenylphosphonium bromide is 0.5:0.5:(9-10), and specifically can be 0.5:0.5:9, 0.5:0.5:9.1, 0.5:0.5:9.2, 0.5:0.5:9.3, 0.5:0.5:9.4, 0.5:0.5:9.5, 0.5:0.5:9.6, 0.5:0.5:9.7, 0.5:0.5:9.8, 0.5:0.5:9.9, 0.5:0.5:10 and the like.

[0024] In the application, the molar ratio of alpha-phenethyl alcohol, acetophenone and methyltriphenylphosphonium bromide is 0.5:0.5:(9.3-9.8).

[0025] In the application, the molar ratio of alpha-phenethyl alcohol, acetophenone and methyltriphenylphosphonium bromide is 0.5:0.5:9.5.

[0026] The application also provides a preparation method of the eutectic solvent. The alpha-phenethyl alcohol, phenylacetone and methyltriphenylphosphonium bromide are mixed and reacted under heating and stirring to form a uniform transparent liquid.

[0027] The application is extremely simple in process by once blending and heating the raw materials (alpha-phenethyl alcohol, phenylacetone, methyltriphenylphosphonium bromide) in a specific ratio under mild conditions.

[0028] In the application, the preparation method comprises: mixing the alpha-phenethyl alcohol, phenylacetone, methyltriphenylphosphonium bromide and furfural, and reacting under heating and stirring to form a uniform transparent liquid.

[0029] The application directly constructs an intelligent solvent system with a dual functional site of “physical dissolution” and “chemical capture” by one-step method. The introduction of a small amount of furfural successfully forms a reversible covalent bonding site in situ in the solvent without increasing the complexity of preparation and the cost of raw materials, so that the final product not only inherits the basic advantages of low eutectic solvent, such as low vapor pressure and low volatility, but also realizes high capacity and high selectivity of styrene molecules, easy desorption and regeneration, thereby solving the fundamental problems of traditional absorbents, such as poor selectivity, low capacity, difficult recycling and high disposal cost of hazardous waste, and providing an efficient and green solution for the resource recovery of styrene VOCs.

[0030] In the application, the reaction is carried out in a water-free environment. If glassware is used for the reaction, all the glassware needs to be dried, and the reagents are as water-free as possible. A small amount of water can interfere with the hydrogen bond network and affect the formation and properties of the eutectic solvent. In the application, the heating temperature of the reaction is 50-80℃.

[0031] It can be understood that the heating temperature should not be too high to prevent the dehydration and other side reactions of alpha-phenethyl alcohol (secondary alcohol) under long-term heating.

[0032] In some embodiments of the application, the heating temperature of the reaction is preferably 60-80℃, and can be 60℃, 65℃, 70℃, 75℃, 80℃ and the like.

[0033] In some embodiments of the application, the reaction is carried out under stirring, and after the solid components are completely dissolved and the system forms a uniform transparent liquid, constant temperature stirring is continued for 0.5-2 h.

[0034] It can be understood that the constant temperature stirring ensures that the internal structure of the eutectic solvent is fully formed and stable. The constant temperature stirring not only ensures the uniform dispersion and mixing of each component at the molecular scale, but more importantly provides the necessary time for the full construction of the hydrogen bond network, especially the stable interaction and balance between trace furfural and other components, thereby ensuring that the final product has a stable, uniform microstructure and a reproducible high adsorption performance.

[0035] The application also provides a use of the above-mentioned eutectic solvent in adsorbing and / or separating styrene in a gas phase and / or a liquid phase.

[0036] The eutectic solvent of the application has high selectivity, high capacity and excellent renewability, and exhibits significant innovation and application potential in the field of styrene recovery and waste gas deep purification.

[0037] The application also provides a method for adsorbing styrene, comprising: At normal pressure and at 20-60℃, the gas containing styrene to be treated is introduced into the above-mentioned eutectic solvent, and after adsorption saturation, the introduction of the gas to be treated is stopped; the eutectic solvent reaching adsorption saturation is heated to obtain styrene. Or, the liquid containing styrene to be treated is mixed with the above-mentioned eutectic solvent, and after standing and layering, the eutectic solvent is distilled to obtain styrene.

[0038] In the application, the methyltriphenylphosphonium bromide has a large molecular weight, and multiple interactions exist, so that the final DES is very viscous at room temperature, and can be preheated to reduce the viscosity before use.

[0039] It can be understood that when the gas containing styrene to be treated is treated, the prepared eutectic solvent can be placed in a solvent storage tank of a bubble column or a packed column. The mixed gas containing styrene is introduced into the eutectic solvent at a certain gas velocity, or the gas passes through a fixed bed filled with the eutectic solvent or the eutectic solvent impregnated packing.

[0040] In the application, the heating temperature is 80-120℃. Since the eutectic solvent itself has very low vapor pressure, and styrene has relatively high volatility, styrene will be preferentially desorbed. The desorbed styrene vapor is condensed by a condenser to recover liquid styrene with high purity. The eutectic solvent after desorption restores the adsorption capacity, and after cooling to the adsorption temperature, it can be reused in the next adsorption cycle.

[0041] In the application, at the gas outlet, an online gas chromatograph or a styrene monitor is used to monitor the concentration of styrene in the outlet gas in real time. When the outlet concentration reaches the breakthrough point, it is considered that the adsorption of the solvent is close to saturation.

[0042] In the present application, the liquid to be treated containing styrene is usually subjected to separation of styrene in a stirred tank or an extraction column, and the eutectic solvent is mixed with the organic phase containing styrene in the stirred tank to contact sufficiently. After static stratification, styrene is selectively enriched in the DES phase. Distillation of the DES phase by heating / pressure reduction can realize separation and recovery of styrene and solvent.

[0043] The eutectic solvent of alpha-phenylethanol / acetophenone / methyltriphenylphosphonium bromide prepared by the one-step method of the present application realizes a breakthrough in adsorption performance. On the basis of maintaining low volatility and high stability, the eutectic solvent exhibits high adsorption capacity and high selectivity for styrene gas far exceeding traditional adsorbents through the triple synergistic mechanism of ion-π interaction, π-π stacking interaction and reversible covalent bonding; at the same time, after adsorption saturation, only mild heating is needed to realize efficient desorption of styrene and recycling of the solvent, completely solving the industry pain points of difficult regeneration of adsorbents and high disposal cost of hazardous waste in the prior art, and providing a green, economic and efficient solution for resource recovery of styrene tail gas.

[0044] In order for those skilled in the art to more clearly understand the technical solutions of the present application, the technical solutions of the present application will be described in detail below in conjunction with specific examples.

[0045] Example 1 The present example provides a eutectic solvent consisting of alpha-phenylethanol, acetophenone and methyltriphenylphosphonium bromide, and the molar ratio of alpha-phenylethanol, acetophenone and methyltriphenylphosphonium bromide is 0.5:0.5:9.5.

[0046] The preparation method of the eutectic solvent provided in the present example includes the following steps: Alpha-phenylethanol, acetophenone and methyltriphenylphosphonium bromide are mixed in proportion, and reacted under heating (70℃) and stirring conditions to form a uniform transparent liquid, and constant temperature stirring is continued for 1 h to obtain the eutectic solvent.

[0047] Example 2 The present example provides a eutectic solvent consisting of alpha-phenylethanol, acetophenone, methyltriphenylphosphonium bromide and furfural, and the molar ratio of alpha-phenylethanol, acetophenone and methyltriphenylphosphonium bromide is 0.5:0.5:9.5. The mass of furfural is 3% of the mass of methyltriphenylphosphonium bromide.

[0048] The preparation method of the eutectic solvent provided in the present example includes the following steps: Alpha-phenylethanol, acetophenone, methyltriphenylphosphonium bromide and furfural are mixed in proportion, and reacted under heating (70℃) and stirring conditions to form a uniform transparent liquid, and constant temperature stirring is continued for 1 h to obtain the eutectic solvent.

[0049] Example 3 The present example provides a deep eutectic solvent consisting of α-phenylethanol, phenylethanone, methyltriphenylphosphonium bromide and furfural, the molar ratio of α-phenylethanol, phenylethanone and methyltriphenylphosphonium bromide being 0.5:0.5:9. The mass of furfural is 3% of the mass of methyltriphenylphosphonium bromide.

[0050] The preparation method of the deep eutectic solvent provided in the present example is completely consistent with that of Example 2.

[0051] Example 4 The present example provides a deep eutectic solvent consisting of α-phenylethanol, phenylethanone, methyltriphenylphosphonium bromide and furfural, the molar ratio of α-phenylethanol, phenylethanone and methyltriphenylphosphonium bromide being 0.5:0.5:10. The mass of furfural is 3% of the mass of methyltriphenylphosphonium bromide.

[0052] The preparation method of the deep eutectic solvent provided in the present example is completely consistent with that of Example 2.

[0053] Comparative Example 1 The present comparative example provides a deep eutectic solvent consisting of α-phenylethanol and methyltriphenylphosphonium bromide, the molar ratio of α-phenylethanol and methyltriphenylphosphonium bromide being 1:9.5.

[0054] The preparation method of the deep eutectic solvent provided in the present comparative example comprises the following steps: α-phenylethanol and methyltriphenylphosphonium bromide are mixed in proportion, reacted under the condition of heating (70°C) and stirring, a uniform transparent liquid is formed, and constant temperature stirring is continued for 1 h, and the deep eutectic solvent is obtained.

[0055] Comparative Example 2 The present comparative example provides a deep eutectic solvent consisting of α-phenylethanol, phenylethanone and methyltriphenylphosphonium bromide, the molar ratio of α-phenylethanol, phenylethanone and methyltriphenylphosphonium bromide being 0.5:0.5:12.

[0056] The preparation method of the deep eutectic solvent provided in the present comparative example comprises the following steps: α-phenylethanol, phenylethanone and methyltriphenylphosphonium bromide are mixed in proportion, reacted under the condition of heating (70°C) and stirring, a uniform transparent liquid is formed, and constant temperature stirring is continued for 1 h, and the deep eutectic solvent is obtained.

[0057] Comparative Example 3 The present comparative example provides a deep eutectic solvent, which is different from Example 2 in that furfural is replaced by benzaldehyde, and the rest of the composition and the preparation method are completely consistent with those of Example 2.

[0058] Experimental Example 1 The low eutectic solvent obtained in the examples or comparative examples was used as an absorbent to simulate the removal efficiency of styrene in industrial waste gas at different operating temperatures (20°C, 25°C, 30°C, and 35°C). The experiment was carried out under the conditions of fixed inlet gas flow, inlet gas concentration, and absorbent circulation amount. The performance of the absorbent was evaluated by measuring the styrene concentration in the purified gas, and key parameters were provided for the design of industrial devices.

[0059] (1) Experimental device The experimental device mainly includes a waste gas mixing tank, a packed absorption tower, an absorbent buffer tank, a circulating pump, a plate heat exchanger, and an online gas analyzer.

[0060] The bottom of the packed absorption tower is provided with an air inlet connected with the waste gas mixing tank; the top is provided with a purified gas outlet and an absorbent spraying port. The tower is filled with regular fillers to increase the gas-liquid contact area. The volume of the absorbent buffer tank is 22.5 m 3 , which is used to store the absorbent. The absorbent buffer tank is connected with the circulating pump through a pipeline. The outlet pipeline of the circulating pump is divided into two routes: one route returns to the top of the absorption tower to form a circulating loop; the other route is a waste liquid discharge pipeline. A plate heat exchanger is arranged on the circulating pipeline to accurately control the temperature of the absorbent entering the packed absorption tower.

[0061] (2) Test process First, nitrogen and styrene were introduced into the waste gas mixing tank to prepare simulated waste gas. Then, the circulating pump was started, and the benzene ethanol absorbent in the buffer tank was pumped at a fixed flow rate, flowed through the plate heat exchanger for temperature adjustment, and then sprayed into the packed absorption tower from the top. The simulated waste gas enters from the bottom of the absorption tower and is countercurrently contacted with the falling absorbent, and the styrene therein is absorbed. The purified gas is discharged from the packed absorption tower, and its concentration is monitored in real time by the online gas analyzer. The absorbent enriched with styrene returns to the buffer tank, part of which continues to participate in absorption through the small circulating pipeline until its saturation reaches the set value and is discharged as waste liquid.

[0062] The inlet flow of the simulated waste gas is 260 m 3 / h (standard state), the inlet styrene concentration is 8286 mg / m 3 , and the absorbent circulation amount is 5 t / h. When the mass fraction of styrene in the absorbent reaches 10%, the absorbent becomes waste liquid and is discharged.

[0063] By adjusting the plate heat exchanger, the absorbent temperature was controlled at 20°C, 25°C, 30°C, and 35°C, respectively, for comparative test.

[0064] (3) Experimental results The styrene concentration at the purified gas outlet under different absorbent temperatures is shown in Table 1.

[0065] Table 1 Styrene concentration at the outlet of the purification gas

[0066] The experimental results show that the temperature of the absorbent has a significant effect on the absorption effect. The lower the temperature, the lower the outlet concentration of styrene, and the better the absorption effect. In order to ensure that the outlet concentration is still lower than the design value (20 mg / m 3 ) under the most unfavorable working conditions (such as 35℃), engineering design calculations are carried out in this embodiment.

[0067] Experimental Example 2 Taking the styrene co-production device by ethylbenzene co-oxidation method as an example, there are two styrene product storage tanks, one crude styrene storage tank, the pressure is 2 KPaG, the styrene content in the top exhaust gas is 0.8%, and the rest is air after nitrogen purging. The theoretical plate number of the absorption tower is 7, the tower pressure is 5 KPaG, and the tower top temperature is 12℃; the absorbent is the eutectic solvent prepared in the embodiment or the comparative example. The styrene-containing exhaust gas stream enters from the lower part of the absorption tower at a flow rate of 1500 m 3 / h, the tower top absorbent feed rate is 450 kg / h, the tower bottom to tower middle circulating absorption liquid stream flow rate is 1350 kg / h, the tower bottom absorption liquid to separation tower feed stream flow rate is 540 kg / h; the fresh absorbent supplement is 30 kg / h. The theoretical plate number of the separation tower is 5, the tower pressure is 50 KPaG, the reflux ratio is 3, and the tower bottom temperature is 120℃; the separation tower bottom return to the absorption tower stream flow rate is 420 kg / h, the waste oil discharge amount is 5 kg / h; the tower top oil-water separation tank water phase return to the absorbent feed line stream flow rate is 12.5 kg / h, and the tower top oil-water separation tank oil phase to the main device SM refining system stream flow rate is 170.05 kg / h.

[0068] The detection results are shown in Table 2.

[0069] Table 2 Application of the eutectic solvent obtained in the embodiment

[0070] As shown in Table 2, under the same application conditions, the removal rate of styrene in the exhaust gas by the eutectic solvents provided by each embodiment of the present application all reaches more than 99.8%, the total organic matter removal effect is remarkable, and the recovery efficiency is high. Further, the eutectic solvents provided by each embodiment of the present application have high recovery utilization rate and strong stability, the reversible covalent bonding mechanism ensures that the styrene is almost completely released under mild conditions, and the stable eutectic structure makes the performance almost not attenuate after multiple uses. This fundamentally solves the industry problem that the multi-ethylbenzene residual oil and other one-time absorbents must be disposed as hazardous waste due to the inability to efficiently regenerate and the rapid performance attenuation in the background art, realizes efficient recycling of the absorbent, and greatly reduces the operating cost and environmental risk.

[0071] In contrast, the effect of the comparative example is significantly worse: Comparative Example 1: Its eutectic solvent is composed of α-phenethyl alcohol and methyltriphenylphosphonium bromide, without containing acetophenone component. The application results show that its removal rate of styrene is significantly lower than each example, proving that the specific combination of acetophenone, α-phenethyl alcohol and methyltriphenylphosphonium bromide is necessary to achieve excellent styrene absorption performance, and the lack of acetophenone will result in the solvent performance cannot reach the level of the present application.

[0072] Comparative Example 2: Although it contains α-phenethyl alcohol, acetophenone and methyltriphenylphosphonium bromide three components, the molar ratio of methyltriphenylphosphonium bromide exceeds the scope of the present application. Its application effect is obviously worse than the example, the removal rate of styrene is lower, which shows that the molar ratio of each component needs to be controlled within a certain range, and too high proportion of methyltriphenylphosphonium bromide will destroy the synergy of the system, which is not conducive to performance optimization.

[0073] Comparative Example 3: The difference between its composition and Example 2 is that the additive furfural is replaced by an equal amount of benzaldehyde. The application results show that its removal efficiency of styrene is far less than Example 2 containing furfural, which shows that furfural as a specific additive has an irreplaceable promoting effect on further improving the removal effect of styrene, and its effect is not as good as that of conventional aldehyde additives.

[0074] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A eutectic solvent, characterized in that, It includes a hydrogen bond donor and a hydrogen bond acceptor; the hydrogen bond donor is α-phenylethanol, and the hydrogen bond acceptor is acetophenone and methyltriphenylphosphine bromide; The molar ratio of α-phenylethanol, acetophenone and methyltriphenylphosphine bromide is (0.4-0.6):(0.4-0.6):(9-10).

2. The eutectic solvent as described in claim 1, characterized in that, The eutectic solvent also includes furfural, the mass of which is 1%-5% of the mass of methyltriphenylphosphine bromide.

3. The eutectic solvent as described in claim 1, characterized in that, The molar ratio of α-phenylethanol, acetophenone, and methyltriphenylphosphine bromide is 0.5:0.5:(9-10); Alternatively, the molar ratio of α-phenylethanol, acetophenone, and methyltriphenylphosphine bromide is 0.5:0.5:(9.3-9.8).

4. The eutectic solvent as described in claim 1, characterized in that, The molar ratio of α-phenylethanol, acetophenone, and methyltriphenylphosphine bromide is 0.5:0.5:9.

5.

5. A method for preparing a eutectic solvent according to any one of claims 1-4, characterized in that, include: α-Phenylacetylethanol, acetophenone, and methyltriphenylphosphine bromide were mixed and reacted under heating and stirring conditions to form a homogeneous, transparent liquid.

6. The preparation method according to claim 5, characterized in that, The reaction is heated at a temperature of 50~80℃.

7. The preparation method according to claim 6, characterized in that, The reaction is heated at a temperature of 60~80℃.

8. The preparation method according to claim 5, characterized in that, The reaction was carried out under stirring conditions. After the solid components were completely dissolved and the system formed a homogeneous and transparent liquid, the mixture was stirred at a constant temperature for 0.5-2 hours.

9. The use of the eutectic solvent according to any one of claims 1-4 in the adsorption and / or separation of styrene in the gas and / or liquid phases.

10. A method for adsorbing styrene, characterized in that, include: At atmospheric pressure and 20-60°C, the gas to be treated containing styrene is introduced into the eutectic solvent described in any one of claims 1-4. After adsorption saturation, the introduction of the gas to be treated is stopped; the eutectic solvent that has reached adsorption saturation is heated to obtain styrene. Alternatively, the liquid to be treated containing styrene is mixed with the eutectic solvent described in any one of claims 1-4, allowed to stand and separate into layers, and the eutectic solvent is distilled to obtain styrene.

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