A benzyltriethyl eutectic solvent, its preparation method, and its application in the separation of pyridine.

Abstract

This invention discloses a benzyltriethyl eutectic solvent, its preparation method, and its application in the separation of pyridine. The benzyltriethyl eutectic solvent is placed in an organic solution containing pyridine, and pyridine is extracted and separated under constant temperature and stirring conditions. The benzyltriethyl eutectic solvent prepared by this invention has a strong ability to capture pyridine; at the same time, this benzyltriethyl eutectic solvent has the advantages of simple synthesis, low price, and simple extraction and separation operation.

Description

Technical Field

[0001] This invention relates to the field of solution chemistry, specifically to a benzyltriethyl eutectic solvent, its preparation method, and its application in the separation of pyridine. Background Technology

[0002] Pyridine is a six-membered heterocyclic compound containing one nitrogen atom. Industrially, it is used as a denaturing agent, dyeing auxiliary, and a raw material for synthesizing a range of products, including pharmaceuticals, disinfectants, and dyes, giving it high industrial value. However, pyridine and its homologues are present in coal gas, coal tar, bone tar, shale oil, and petroleum, and are released during the use of petroleum products. This not only harms the environment but also poses a significant threat to human health. Therefore, removing pyridine from oil is crucial, both from the perspective of its industrial value and for oil purification.

[0003] Traditional methods are not only complex to operate, but also produce byproducts, causing new environmental pollution. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a benzyltriethyl eutectic solvent, its preparation method, and its application in the separation of pyridine. This method is simple to operate and has excellent results.

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

[0006]

[0007] A method for preparing a benzyltriethyl eutectic solvent includes the following steps: mixing benzyltriethylammonium chloride and propionic acid and stirring the mixture until a homogeneous and transparent liquid is formed, followed by vacuum drying to obtain the target product.

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

[0009] Furthermore, the stirring reaction takes 2 to 3 hours.

[0010] This invention provides the application of a benzyltriethyl eutectic solvent as an extractant in the extraction of pyridine.

[0011] Further, the method is as follows: benzyltriethyl eutectic solvent is placed in an organic solution containing pyridine, and pyridine is extracted and separated under constant temperature and stirring conditions.

[0012] Furthermore, by mass ratio, benzyltriethyl eutectic solvent: pyridine-containing organic solution = 1:1 to 3.

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

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

[0015] The beneficial effects of this invention are:

[0016] 1. This invention utilizes benzyltriethyl eutectic solvent as an extractant to extract and separate pyridine. The selected benzyltriethyl eutectic solvent can form hydrogen bonds with pyridine, which can successfully extract pyridine from organic solutions with a high extraction rate.

[0017] 2. This invention utilizes benzyltriethyl eutectic solvent as an extractant to extract and separate pyridine, which is in line with the concept of green environmental protection and is more beneficial to the life and survival of humans, animals and plants. Attached Figure Description

[0018] Figure 1 This is the 1H NMR spectrum of the benzyltriethyl eutectic solvent in Example 1.

[0019] Figure 2 This is the infrared spectrum of the benzyltriethyl eutectic solvent in Example 1. Detailed Implementation

[0020] To better understand the above technical solutions, the technical solutions of the embodiments of this application will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of this application and the specific features in the embodiments are detailed descriptions of the technical solutions of the embodiments of this application, rather than limitations on the technical solutions of this application. In the absence of conflict, the embodiments of this application and the technical features in the embodiments can be combined with each other.

[0021] A first aspect of the present invention provides a benzyltriethyl eutectic solvent having the structural formula shown in (I):

[0022]

[0023] The benzyltriethyl eutectic solvent provided by this invention is a "quasi-ionic liquid" composed of hydrogen bond acceptors and hydrogen bond donors. In addition to having the excellent characteristics of ionic liquids, it also has the advantages of simple synthesis operation, low raw material cost, and high atom utilization. The benzyltriethyl eutectic solvent can form hydrogen bonds with pyridine, which can successfully extract and separate pyridine from organic solutions, with the best extraction effect.

[0024] A second aspect of the present invention provides a method for preparing a benzyltriethyl eutectic solvent, comprising the following steps: mixing benzyltriethylammonium chloride and propionic acid and stirring the mixture until a homogeneous transparent liquid is formed, followed by vacuum drying to obtain the target product.

[0025] The preparation method provided by this invention has the lowest cost and the simplest operation. The prepared benzyltriethyl eutectic solvent has the best extraction effect on pyridine, which can maximize economic benefits.

[0026] In some feasible implementations, the molar ratio of benzyltriethylammonium chloride to propionic acid is further 1:1 to 3.

[0027] The eutectic solvent synthesized using this molar ratio range exhibits lower viscosity and better stability. Furthermore, the preferred molar ratio is benzyltriethylammonium chloride:propionic acid = 1:2.

[0028] In some feasible implementations, the stirring reaction is further carried out over a period of 2 to 3 hours.

[0029] According to this invention, performing the reaction at this time ensures complete reaction and avoids wasting unnecessary time.

[0030] A third aspect of the present invention provides the application of benzyltriethyl eutectic solvent as an extractant in the extraction of pyridine.

[0031] The benzyltriethyl eutectic solvent provided by this invention can form hydrogen bonds with pyridine, which can successfully extract and separate pyridine from organic solutions. The extraction effect is optimal, and the extraction efficiency of benzyltriethyl eutectic solvent for pyridine can reach 98.5%.

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

[0033] In some feasible embodiments, further, the ratio of benzyltriethyl eutectic solvent to pyridine-containing organic solution is 1:1 to 3 by mass.

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

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

[0036] From the perspectives of ensuring a high extraction rate and avoiding waste of raw materials, this invention preferably uses a pyridine concentration of 0.1–0.3 g / L. -1 .

[0037] In some feasible implementations, the constant temperature is further defined as 50–70°C.

[0038] This temperature is commonly used in actual operation and is relatively easy to control. Temperatures above 70℃ will inevitably increase energy consumption and are not conducive to the concept of environmental protection. Temperatures below 50℃ have slightly less reference value for practical applications.

[0039] Example 1: A method for preparing a benzyltriethyl eutectic solvent (I) is as follows:

[0040] The benzyltriethylammonium chloride (BTEAC) with structural formula (II) was dried under vacuum at 60°C in a molar ratio of 1:2 with propionic acid as shown in formula (III). The dried benzyltriethylammonium chloride and propionic acid (Pro) with structural formula (III) were mixed and stirred at room temperature for 2-3 hours until a homogeneous transparent liquid was formed. The resulting product was dried under vacuum at 60°C to obtain the target product, benzyltriethyl eutectic solvent (BTEAC-Pro), with structural formula (I).

[0041]

[0042] (II) Characterization methods:

[0043] (1) 1H NMR spectrum: 1H NMR spectrum of benzyltriethyl eutectic solvent 1 ¹H NMR characterization (300 MHz, solvent: DMSO-d6) is shown in the attached figure. Figure 1 Analysis of the proton nuclear magnetic resonance spectrum revealed that... 1 The chemical shifts, number of resonance peaks, and integral area of ​​the H NMR were consistent with those of the target eutectic solvent, and no impurity peaks were found.

[0044] (2) Infrared spectrum: Infrared characterization of benzyltriethyl eutectic solvent is shown in Appendix Figure 2 Infrared spectral analysis revealed that the infrared spectrum of the eutectic solvent contained characteristic peaks of both the hydrogen bond acceptor (benzyltriethylammonium chloride) and the hydrogen bond donor (propionic acid), without the formation of any new characteristic peaks. This indicates that benzyltriethylammonium chloride and propionic acid did not undergo a chemical reaction to produce a new substance, but were simply bonded together through hydrogen bond interactions.

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

[0046] (I) Extraction and Separation Experiment

[0047] Dissolve a certain amount of pyridine in n-octane to prepare a pyridine concentration of 0.2 g / L. -1 A pyridine-containing n-octane solution is prepared for later use.

[0048] Weigh 1g of benzyltriethyl eutectic solvent into a 10mL graduated test tube, add 2g of pyridine-containing n-octane solution, and carry out the extraction and separation experiment of pyridine by magnetic stirring at 60℃.

[0049] After extraction for 60 min, the sample was allowed to stand for 2 h. The concentration of pyridine in the n-octane phase at a wavelength of 313 nm was measured using UV-Vis spectrophotometry. Three measurements were taken as the average value, 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 octane solution containing pyridine, C f This represents the concentration of remaining pyridine in the n-octane phase.

[0053] After extraction with benzyltriethyl eutectic solvent, the extraction efficiency of benzyltriethyl eutectic solvent for pyridine was calculated to be 98.5%.

[0054] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. The application of a benzyltriethyl eutectic solvent as an extractant in the extraction of pyridine, characterized in that, The benzyltriethyl eutectic solvent was placed in an octane solution containing pyridine, and the pyridine was extracted and separated under constant temperature and stirring conditions. The benzyltriethyl eutectic solvent has the structural formula shown in (I): （Ⅰ）。 2. The application according to claim 1, characterized in that, The mass ratio of benzyltriethyl eutectic solvent to pyridine-containing n-octane solution is 1:1 to 3.

3. The application according to claim 1, characterized in that, In an octane solution containing pyridine, the concentration of pyridine is 0.1–0.3 g / L. -1 .

4. The application according to claim 1, characterized in that, The constant temperature is 50–70 °C.

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