Benzyltriethyl deep-eutectic solvent, preparation method thereof and application of benzyltriethyl deep-eutectic solvent in pyridine separation

Abstract

The invention discloses a benzyltriethyl eutectic solvent, a preparation method thereof and application of the benzyltriethyl eutectic solvent in pyridine separation. The benzyltriethyl eutectic solvent is placed in an organic solution containing pyridine, and pyridine is extracted and separated under the conditions of constant temperature and stirring. The benzyltriethyl eutecticevaporate solvent prepared by the preparation method disclosed by the invention has relatively strong trapping capability on pyridine; meanwhile, the benzyltriethyl eutectic solvent has the advantages of simple synthesis, low price and the like, and the extraction separation operation is simple.

Description

Technical Field

[0001] The invention relates to the field of solution chemistry, and in particular to a benzyltriethyl low eutectic solvent and a preparation method thereof and application thereof in separating pyridine. Background Art

[0002] Pyridine is a six-membered heterocyclic compound containing a nitrogen heteroatom. It can be used as a denaturant, dyeing aid, and raw material for synthesizing a series of products (including medicines, disinfectants, dyes, etc.) in industry, and has high industrial value. However, pyridine and its homologues exist in coal gas, coal tar, bone tar, shale oil and petroleum, and will be released during the use of oil products, which is not only not conducive to environmental protection, but also greatly endangers human health. Therefore, whether considering the industrial value of pyridine or the purification of oil products, it is crucial to remove pyridine from oil.

[0003] Traditional methods are not only complicated to operate, but also produce by-products, causing new environmental pollution. Summary of the invention

[0004] In order to solve the above-mentioned technical problems, the present invention provides a benzyltriethyl low eutectic solvent and a preparation method thereof and an application thereof in separating pyridine. The method is simple to operate and has excellent effect.

[0005] To achieve the above object, the technical solution adopted by the present invention is: a benzyl triethyl deep eutectic solvent having the structural formula shown in (I):

[0006]

[0007] A preparation method of a benzyltriethyl low eutectic solvent comprises the following steps: mixing benzyltriethylammonium chloride and propionic acid, stirring and reacting the mixture until a uniform transparent liquid is formed, and vacuum drying the mixture to obtain a target product.

[0008] Furthermore, in a molar ratio, benzyltriethylammonium chloride: propionic acid = 1:1-3.

[0009] Furthermore, the stirring reaction has a reaction time of 2 to 3 hours.

[0010] The invention provides an application of a benzyltriethyl low eutectic solvent as an extractant in extracting pyridine.

[0011] Furthermore, the method is as follows: placing benzyl triethyl low eutectic solvent in an organic solution containing pyridine, and extracting and separating pyridine under constant temperature and stirring conditions.

[0012] Furthermore, in terms of mass ratio, benzyltriethyl low eutectic solvent: pyridine-containing organic solution = 1:1-3.

[0013] Furthermore, in the organic solution containing pyridine, the concentration of pyridine is 0.1 to 0.3 g / L. -1 .

[0014] Furthermore, the constant temperature is 50-70°C.

[0015] The beneficial effects of the present invention are:

[0016] 1. The present invention uses benzyl triethyl low eutectic solvent as an extractant to extract and separate pyridine. The selected benzyl triethyl low eutectic solvent can form a hydrogen bond with pyridine, and pyridine can be successfully extracted from the organic solution with a high extraction rate.

[0017] 2. The present invention uses benzyl triethyl low eutectic solvent as an extractant to extract and separate pyridine, which is conducive to the concept of green environmental protection and is more conducive to the life and survival of humans, animals and plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of the benzyltriethyl deep eutectic solvent of Example 1.

[0019] Figure 2 This is the infrared spectrum of the benzyltriethyl deep eutectic solvent of Example 1. DETAILED DESCRIPTION

[0020] In order to better understand the above-mentioned technical scheme, the technical scheme of the embodiments of the present application is described in detail below through the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present application and the specific features in the embodiments are detailed descriptions of the technical scheme of the embodiments of the present application, rather than limitations on the technical scheme of the present application. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments may be combined with each other.

[0021] In a first aspect of an embodiment of the present invention, there is provided a benzyl triethyl deep eutectic solvent having a structural formula as shown in (I):

[0022]

[0023] The benzyl triethyl low eutectic solvent provided by the present invention is a "quasi-ionic liquid" composed of a hydrogen bond acceptor and a hydrogen bond donor. In addition to having the excellent characteristics of an ionic liquid, it also has the characteristics of simple synthesis operation, low raw material cost, high atomic utilization rate, etc. The benzyl triethyl low eutectic solvent can form a hydrogen bond with pyridine, and can successfully extract and separate pyridine from an organic solution, with the best extraction effect.

[0024] According to a second aspect of an embodiment of the present invention, a method for preparing a benzyltriethyl low eutectic solvent is provided, comprising the following steps: mixing benzyltriethylammonium chloride and propionic acid, stirring the mixture to react until a uniform transparent liquid is formed, and vacuum drying the mixture to obtain a target product.

[0025] The preparation method provided by the present invention has the lowest cost and the simplest operation. The prepared benzyltriethyl low eutectic solvent has the best effect of extracting pyridine, and can achieve maximum economic benefit.

[0026] In some feasible implementations, further, in a molar ratio, benzyltriethylammonium chloride:propionic acid=1:1-3.

[0027] In the present invention, the low eutectic solvent synthesized by using this molar ratio range has lower viscosity and better stability. Furthermore, in the present invention, preferably, in a molar ratio, benzyltriethylammonium chloride: propionic acid = 1:2.

[0028] In some feasible embodiments, further, the stirring reaction has a reaction time of 2 to 3 hours.

[0029] According to the present invention, carrying out the reaction within this time can ensure that the reaction is complete and avoid wasting unnecessary time.

[0030] According to a third aspect of the embodiments of the present invention, a method for extracting pyridine is provided by using a benzyltriethyl eutectic solvent as an extractant.

[0031] The benzyl triethyl low eutectic solvent provided by the present invention can form a hydrogen bond with pyridine, and can successfully extract and separate pyridine from an organic solution, with the best extraction effect. The extraction efficiency of the benzyl triethyl low eutectic solvent for pyridine can reach 98.5%.

[0032] In some feasible implementations, further, the method is as follows: placing benzyltriethyl low eutectic solvent in an organic solution containing pyridine, and extracting and separating pyridine under constant temperature and stirring conditions.

[0033] In some feasible implementations, further, by mass ratio, benzyltriethyl low eutectic solvent: pyridine-containing organic solution = 1:1-3.

[0034] According to the present invention, the effect of extracting more pyridine with the least amount of extractant can be achieved according to this mass ratio. A too low mass ratio will affect the extraction rate of pyridine, while a too high mass ratio will cause unnecessary waste.

[0035] In some feasible embodiments, further, in the organic solution containing pyridine, the concentration of pyridine is 0.1 to 0.3 g / L -1 .

[0036] In the present invention, from the perspectives of ensuring a high extraction rate and avoiding waste of raw materials, the preferred concentration of pyridine is 0.1 to 0.3 g / L. -1 .

[0037] In some feasible embodiments, further, the constant temperature is 50-70°C.

[0038] This temperature is commonly used in actual operation and is relatively easy to control. A temperature higher than 70°C will inevitably increase energy consumption, which is not conducive to the concept of environmental protection development. A temperature lower than 50°C has a slightly lower reference value for actual applications.

[0039] Example 1 A benzyl triethyl deep eutectic solvent (I) is prepared as follows:

[0040] In a molar ratio of benzyltriethylammonium chloride: propionic acid = 1:2, benzyltriethylammonium chloride (BTEAC) shown in the structural formula (II) is vacuum dried at 60°C. The dried benzyltriethylammonium chloride and propionic acid (Pro) shown in the structural formula (III) are mixed and stirred at room temperature for 2 to 3 hours until a uniform transparent liquid is formed. The obtained product is vacuum dried at 60°C to obtain the target product benzyltriethyl deep eutectic solvent (BTEAC-Pro), the structural formula of which is shown in (I).

[0041]

[0042] (II) Characterization methods:

[0043] (1) H NMR spectrum: H NMR spectrum of benzyltriethyl deep eutectic solvent 1 H NMR characterization (300 MHz, solvent: DMSO-d6) Figure 1 . Analysis of the nuclear magnetic resonance hydrogen spectrum revealed that 1 The chemical shift, number of resonance peaks and integrated area of ​​H NMR were consistent with those of the target deep eutectic solvent, and no impurity peaks were found.

[0044] (2) Infrared spectrum: The infrared characterization of benzyl triethyl eutectic solvent is shown in the attached Figure 2 . Analysis of the infrared spectrum shows that the infrared spectrum of the low eutectic solvent contains both the characteristic peaks of the hydrogen bond acceptor (benzyltriethylammonium chloride) and the characteristic absorption peaks of the hydrogen bond donor (propionic acid), and no new characteristic peaks are generated, indicating that there is no chemical reaction between benzyltriethylammonium chloride and propionic acid to produce new substances, but they are only combined through hydrogen bond interactions.

[0045] Example 2 Application of a benzyltriethyl deep eutectic solvent as an extractant in the extraction and separation of pyridine

[0046] (I) Extraction and separation experiment

[0047] Take a certain amount of pyridine and dissolve it in n-octane to prepare a pyridine concentration of 0.2g / L -1 The n-octane solution containing pyridine is set aside.

[0048] 1 g of benzyltriethyl deep eutectic solvent was weighed into a 10 mL graduated test tube, 2 g of n-octane solution containing pyridine was added, and an extraction and separation experiment of pyridine was carried out at 60° C. under magnetic stirring.

[0049] After 60 minutes of extraction, the mixture was allowed to stand for 2 hours. The concentration of pyridine in the n-octane phase was measured at a wavelength of 313 nm using UV-visible spectrophotometry. The average value of three measurements was taken, and the relative error was controlled within 3% to ensure the accuracy of the data.

[0050] The extraction efficiency E (%) of pyridine is calculated according to the following formula (1-1):

[0051] E(%)=[(C0-C f ) / C0] × 100 (1-1)

[0052] Where C0 represents the initial concentration of pyridine in the n-octane solution containing pyridine, C f is the concentration of residual pyridine in the n-octane phase.

[0053] After extraction with the benzyl triethyl deep eutectic solvent, it was calculated that the extraction efficiency of the benzyl triethyl deep eutectic solvent for pyridine was 98.5%.

[0054] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A benzyl triethyl deep eutectic solvent, characterized in that: The benzyl triethyl low eutectic solvent has the structural formula shown in (I):

2. A method for preparing a benzyl triethyl deep eutectic solvent, characterized in that: The preparation method comprises the following steps: mixing benzyltriethylammonium chloride and propionic acid, stirring and reacting the mixture until a uniform transparent liquid is formed, and vacuum drying the mixture to obtain a target product.

3. The preparation method according to claim 2, characterized in that: In molar ratio, benzyltriethylammonium chloride: propionic acid = 1:1~3.

4. The preparation method according to claim 2, characterized in that: The stirring reaction has a reaction time of 2 to 3 hours.

5. Use of the benzyltriethyl deep eutectic solvent according to claim 1 as an extractant in extracting pyridine.

6. The use according to claim 5, characterized in that: The method is as follows: benzyl triethyl low eutectic solvent is placed in an organic solution containing pyridine, and pyridine is extracted and separated under constant temperature and stirring conditions.

7. The use according to claim 6, characterized in that: In terms of mass ratio, benzyl triethyl eutectic solvent: organic solution containing pyridine = 1:1-3.

8. The use according to claim 6, characterized in that: In the organic solution containing pyridine, the concentration of pyridine is 0.1~0.3g / L -1 .

9. The use according to claim 6, characterized in that: The constant temperature is 50-70°C.

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