A method for highly selective extraction of vanillin using an ionic liquid / salt / sulfonylated calix[4]arene aqueous two-phase system

Abstract

The present invention discloses a method for highly selectively extracting vanillin using an ionic liquid / salt / sulfonylated calix[4]arene aqueous two-phase system. n The extract containing vanillin is added to the aqueous two-phase system of mim]Br / Na3C6H5O7 / SC[4], mixed, centrifuged to separate the two phases completely, and the upper phase is collected to obtain the extracted vanillin. n mim]Br / Na3C6H5O7 aqueous two-phase system increases the polarity difference between the two phases, promotes the formation of the two-phase system, improves the distribution coefficient of vanillin in the two-phase system, and can highly selectively extract vanillin from a variety of structural analogs. The method is simple and easy.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic separation, and relates to a method for highly selectively extracting vanillin (Van) by using an ionic liquid / salt / sulfonylated calix[4]arene aqueous two-phase system. n A method for highly selective extraction of vanillin using a two-phase aqueous system of (acid) / sodium citrate (Na3C6H5O7) / sulfonylated calix[4]arene (SC[4]). Background Art

[0002] Vanillin, a fragrance enhancer and fixer, is widely used in the cosmetics and food industries. Therefore, highly selective extraction of vanillin is of great significance. Currently, selective extraction methods primarily include membrane separation and molecular imprinting. However, these methods are time-consuming and complex, leading to the need for a simple, effective, and highly selective extraction method.

[0003] Aqueous two-phase system (ATPS) is an immiscible aqueous solution system formed by dissolving several substances in water at appropriate concentrations under certain conditions. When ATPS is used to extract target substances (such as metal ions, organic molecules, and biomolecules), the experimental conditions are mild, the cost is low, and the time consumption is less. Souza et al. (INSouza et al., Fluid Phase Equilibria, 2018, 476, 179-185) used ATPS formed by maltose and acetonitrile to extract vanillin and found that the maximum partition coefficient of vanillin was only 12. When Veloso et al. (AVVeloso et al., Food and Bioproducts Processing, 2020, 119, 268-276) used ethanol / dipotassium hydrogen phosphate ATPS to extract vanillin, the maximum partition coefficient of vanillin was 22. Claudio et al. (AFMClaudio et al., Separation and Purification Technology, 2010, 75, 39-47) used ionic liquids ([C2mim]Cl, [C4mim]Cl, [C6mim]Cl, [C7mim]Cl, [C 10When vanillin was extracted using [Dmim]Cl, [C7H7mim]Cl, [amim]Cl, [OHC2mim]Cl) / K3PO4 ATPS, the distribution coefficients were 36.5, 45.0, 49.6, 42.4, 2.7, 44.2, 36.5, and 23.0, respectively. Arzideh et al. (SM Arzideh et al., Journal of Molecular Liquids, 2021, 332, 115860) used [Dmim]Cl / 2-propanol / K2HPO4 ATPS to extract vanillin and tryptophan, with distribution coefficients of 389.4 and 66.5, respectively, but the selectivity of vanillin for tryptophan was only 5.9. In summary, when vanillin is extracted using the existing ATPS, although the distribution coefficient of vanillin is high, the selectivity of ATPS for vanillin needs to be improved. Summary of the Invention

[0004] The object of the present invention is to provide a method for highly selectively extracting vanillin using an ionic liquid / salt / sulfonylated calix[4]arene aqueous two-phase system.

[0005] The technical solutions for achieving the purpose of the present invention are as follows:

[0006] The invention discloses a method for highly selectively extracting vanillin using an ionic liquid / salt / sulfonylated calix[4]arene aqueous two-phase system, which comprises the following steps: adding a liquid to be extracted containing vanillin to the ionic liquid / salt / sulfonylated calix[4]arene aqueous two-phase system, mixing the liquid, centrifuging the system, separating the two phases completely, and collecting the upper phase, which is the extracted vanillin; the ionic liquid / salt / sulfonylated calix[4]arene aqueous two-phase system is [C n mim]Br / Na3C6H5O7 / SC[4] biphasic system, wherein the ionic liquid is 1-hexyl-3-methylimidazolium bromide ([C6mim]Br) or 1-decyl-3-methylimidazolium bromide ([C 10 mim]Br).

[0007] The structural formula of SC[4] described in the present invention is: The structural formula of [C6mim]Br is: [C 10 The structural formula of mim]Br is:

[0008] In the present invention, the [C n mim]Br / Na3C6H5O7 / SC[4] aqueous two-phase system, n The concentrations of mim]Br and Na3C6H5O7 are not particularly limited as long as they are within the range of [C n mim]Br / Na3C6H5O7 two-phase aqueous system, specifically, [Cn The concentration of mim]Br can be 5 wt.% to 90 wt.%, and the concentration of Na3C6H5O7 can be 0.4 wt.% to 40 wt.%.

[0009] In a specific embodiment of the present invention, the [C n mim]Br / Na3C6H5O7 / SC[4] aqueous two-phase system, [C n The concentration of mim]Br is 15wt.% to 35wt.%, and the concentration of Na3C6H5O7 is 15wt.% to 25wt.%; preferably, [C n The concentration of mim]Br is 25wt.%~35wt.%, and the concentration of Na3C6H5O7 is 20wt.%~25wt.%.

[0010] In the present invention, the [C n In the aqueous two-phase system of [C]Br / Na3C6H5O7 / SC[4], the concentration of SC[4] is not particularly limited, as long as it is greater than 0 but not more than 10wt.%, it can increase the polarity difference between the two phases and promote [C n mim]Br / Na3C6H5O7 aqueous two-phase system was formed to improve [C n Selective extraction effect of vanillin by mim]Br / Na3C6H5O7 aqueous two-phase system.

[0011] In a specific embodiment of the present invention, the [C n In the mim]Br / Na3C6H5O7 / SC[4] aqueous two-phase system, the concentration of SC[4] is 5wt.%~10wt.%.

[0012] Compared with the prior art, the present invention has the following advantages:

[0013] (1) The present invention first discovered that the sulfonylated calix[4]arene was introduced into [C n mim]Br / Na3C6H5O7 aqueous two-phase system, the polarity difference between the two phases can be increased, promoting the formation of the aqueous two-phase.

[0014] (2) The present invention further discovered that the introduction of sulfonylated calix[4]arene into [C nIn the aqueous two-phase system [C6mim]Br / Na3C6H5O7, highly selective extraction of vanillin can be achieved. When the composition of the aqueous two-phase system is [C6mim]Br (25wt.%) / Na3C6H5O7 (20wt.%), the concentration of SC[4] increases from 0wt.% to 10wt.%, the distribution coefficient of mandelic acid (MA) decreases from 8.6 to 5.8, the distribution coefficient of phenylalanine (Phe) remains unchanged at 2.4, the distribution coefficient of tryptophan (Trp) increases from 5.6 to 15.6, and the distribution coefficient of vanillin increases from 14.4 to 124.8. The selectivity of vanillin for mandelic acid, phenylalanine, and tryptophan increases from 1.67, 6.26, and 2.57 to 21.52, 49.92, and 8.0, respectively, which significantly improves the selectivity of vanillin relative to the other three structurally similar compounds. In addition, by further increasing the concentration of [C6mim]Br in the aqueous two-phase system, the selectivity of vanillin for mandelic acid, phenylalanine, and tryptophan increases from 1.67, 6.26, and 2.57 to 21.52, 49.92, and 8.0, respectively, which significantly improves the selectivity of vanillin relative to the other three structurally similar compounds. n mim]Br or Na3C6H5O7 concentration can further improve the distribution coefficient and selectivity of vanillin. The best selectivity condition is [C 10 mim]Br (25wt.%) / Na3C6H5O7 (25wt.%), at this time, the selectivity of vanillin for mandelic acid, phenylalanine, and tryptophan were 29.23, 112.75, and 13.55, respectively, which is suitable for the simple and efficient extraction of vanillin. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 For SC[4] vs. [C n mim]Br / Na3C6H5O7 ATPS formation.

[0016] Figure 2 This is a graph showing the effect of the composition of [C6mim]Br / Na3C6H5O7 / SC[4]ATPS on the distribution of extracted substances.

[0017] Figure 3 For [C 10 Figure 3. Effect of the composition of mim]Br / Na3C6H5O7 / SC[4]ATPS on the distribution of extracted substances. DETAILED DESCRIPTION

[0018] The present invention will be further described below in conjunction with the embodiments and accompanying drawings.

[0019] To detect different compositions of [C nIn the following examples, in addition to determining the partition coefficient of Van, the selective extraction effect of the two-phase aqueous system on Van was analyzed by measuring the partition coefficients of three substances with similar structures to Van, namely MA, Phe, and Trp. The structural formula of MA is: The structural formula of Phe is: The structural formula of Trp is: The structural formula of Van is:

[0020] In the following examples, [C n mim]Br solution, Na3C6H5O7 solution and SC[4] solution were all prepared using deionized water as solvent.

[0021] MA, Phe, Trp and Van show characteristic absorption peaks at 257, 257, 279 and 280 nm respectively. n A series of MA, Phe, Trp and Van solutions were prepared by using the lower phase of [C]Br / Na3C6H5O7 / SC[4]ATPS as solvent. The standard curves of the corresponding substances were obtained by measuring the absorbance of different concentrations of MA and Phe at 257nm, the absorbance of Trp at 279nm, and the absorbance of Van at 280nm. Then, [C]Br / Na3C6H5O7 / SC[4]ATPS containing MA (40-150mM) or Phe (40-150mM) or Trp (2-50mM) or Van (40-65mM) were prepared. n mim]Br / Na3C6H5O7 / SC[4]ATPSs. The ATPSs were vigorously stirred for 15 minutes, maintained at 25°C for at least 30 minutes, and then centrifuged for 5 minutes to ensure complete separation of the two phases. Finally, the volume of the lower phase of the ATPSs was determined. The concentration of MA, Phe, Trp, or Van in the lower phase was determined using the standard curve, and the distribution coefficient of MA, Phe, Trp, or Van was calculated. It should be noted that the concentration of the extract does not affect its distribution between the two phases of the ATPS.

[0022] The calculation formulas for the distribution coefficients of MA, Phe, Trp and Van are as follows:

[0023] K=(C 总 V 总 -C 下 V 下 ) / C 下 V 下 ,

[0024] Where, K: the distribution coefficient of the substance; C 总 : total concentration of substances in ATPS; V 总: total volume of ATPS; C 下 : the concentration of the substance in the lower phase of ATPS; V 下 : Volume of the lower ATPS phase.

[0025] The selectivity is calculated as follows:

[0026] S1=K Van / K MA , S2=K Van / K Phe , S3=K Van / K Trp

[0027] Among them, S: selectivity, K MA : Partition coefficient of MA, K Phe : Partition coefficient of Phe, K Trp : Partition coefficient of Trp, K Van : Van's distribution coefficient.

[0028] Example 1

[0029] SC[4] vs. [C n Influence of mim]Br / Na3C6H5O7 ATPS phase diagram:

[0030] (1) Add a 30 wt.% aqueous Na₃C₆H₅Oₐ solution dropwise to a 90 wt.% aqueous [C₆mim]Br solution. Once turbidity appears, record the weight of the solution added. Then, add deionized water to clarify the solution, and record the weight of the solvent added. Repeat these steps to calculate the composition of a series of cloud point components.

[0031] (2) Prepare a 90 wt.% [C6mim]Br + 5 wt.% SC[4] solution (A) and a 30 wt.% Na3C6H5O7 + 5 wt.% SC[4] solution (B). Add B dropwise to A. When turbidity appears, record the weight of the added solution. Then add deionized water to clarify the solution, and record the weight of the added solvent. Repeat the above steps to calculate the composition of a series of cloud point components.

[0032] (3) Change [C6mim]Br to [C 10 mim]Br, repeat steps (1) and (2).

[0033] Example 2

[0034] Effect of the composition of [C6mim]Br / Na3C6H5O7 / SC[4]ATPS on the distribution of extractants:

[0035] (1) Prepare 25 wt.% [C6mim]Br / 20 wt.% Na3C6H5O7ATPS containing 65 mM Van. After the solid material is completely dissolved, mix it in a constant temperature mixer at 25°C for 15 min, equilibrate it for 30 min, and centrifuge it for 5 min. The absorbance of the ATPS lower phase is measured at 257 nm, and the Van concentration in the lower phase is calculated based on the standard curve.

[0036] (2) Prepare 25wt.% [C6mim]Br / 20wt.% Na3C6H5O7 / 5wt.% SC[4]ATPS containing 65mM Van. After the solid material is completely dissolved, mix it in a constant temperature mixer at 25°C for 15 minutes, balance it for 30 minutes, and centrifuge it for 5 minutes. The absorbance value of the ATPS lower phase is measured at 257nm.

[0037] (3) Change the concentration of SC[4] in the above ATPS to 10 wt.%, and repeat step (2).

[0038] (4) Change the concentration of [C6mim]Br in the above ATPS to 15 wt.% or 35 wt.%, and repeat steps (1) to (3).

[0039] (5) Change the concentration of Na3C6H5O7 in the above ATPS to 15wt.% or 25wt.%, and repeat steps (1) to (3).

[0040] (6) Change the target molecule from Van to Phe, Trp, or MA and repeat steps (1) to (5).

[0041] According to the calculation formula of distribution coefficient, the distribution coefficient of MA or Phe or Trp or Van in each system was calculated. The results are as follows: Figure 2 According to the selectivity calculation formula, S1, S2 and S3 are obtained, and the results are shown in Table 1.

[0042] Example 3

[0043] [C 10 Effect of the composition of mim]Br / Na3C6H5O7 / SC[4]ATPS on the distribution of extractants:

[0044] (1) Prepare 25 wt.% [C 10 mim]Br / 20wt.% Na3C6H5O7ATPS After the solid material is completely dissolved, mix it in a constant temperature mixer at 25°C for 15 minutes, balance it for 30 minutes, and centrifuge it for 5 minutes. The absorbance of the ATPS lower phase is detected at 257 nm, and the concentration of MA in the lower phase is calculated according to the standard curve.

[0045] (2) Prepare 25 wt.% [C 10 mim]Br / 20wt.%Na3C6H5O7 / 5wt.%SC[4]ATPS After the solid material is completely dissolved, mix it in a constant temperature mixer at 25℃ for 15 minutes, balance it for 30 minutes, centrifuge it for 5 minutes, and detect the absorbance value of the ATPS lower phase at 257nm.

[0046] (3) Change the concentration of SC[4] in the above ATPS to 10 wt.%, and repeat step (2).

[0047] (4) The above ATPS [C 10 The concentration of mim]Br was changed to 15 wt.%, and steps (1) to (3) were repeated.

[0048] (5) Change the concentration of Na3C6H5O7 in the above ATPS to 15wt.% or 25wt.%, and repeat steps (1) to (3).

[0049] (6) Change the target molecule from Van to Phe, Trp, or MA and repeat steps (1) to (5).

[0050] According to the calculation formula of distribution coefficient, the distribution coefficient of MA or Phe or Trp or Van in each system was calculated. The results are as follows: Figure 3 According to the selectivity calculation formula, S1, S2 and S3 are obtained, and the results are shown in Table 1.

[0051] Table 1 ATPS composition and selectivity for Van in each system

[0052]

[0053] Figure 1 It shows that the addition of SC[4] can increase the two-phase region of ATPS, and with the increase of [C n The area of ​​the two-phase region increases with the increase of the length of the mim]Br alkyl chain.

[0054] Figure 2It shows that in 25wt.% [C6mim]Br / 20wt.% Na3C6H5O7 ATPS, when the concentration of SC[4] increases from 0wt.% to 10wt.%, the distribution coefficient of MA decreases from 8.6 to 5.8, the distribution coefficient of Phe remains unchanged at around 2.4, the distribution coefficient of Trp increases from 5.6 to 15.6, and the distribution coefficient of Van significantly increases from 14.4 to 124.8; S1 increases from 1.7 to 21.5, S2 increases from 6.3 to 50.0, and S3 increases from 2.6 to 8.0 (Table 1). When the concentration of Na3C6H5O7 was fixed at 20wt.%, the concentration of [C6mim]Br was changed to 15wt.% and 35wt.%. As the concentration of [C6mim]Br increased, the distribution coefficient of the target molecule increased. In the absence of SC[4], the distribution coefficients of MA, Phe, Trp and Van could reach a maximum of 45.5, 5.8, 31.4 and 405.7, respectively. At this time, S1, S2 and S3 were 8.94, 70.0 and 12.9, respectively (Table 1). When 10wt.% SC[4] was present, the distribution coefficient of MA increased from 1.4 to 16.1, the distribution coefficient of Phe increased from 1.7 to 6.5, the distribution coefficient of Trp increased from 6.8 to 43.1, and the distribution coefficient of Van increased from 33.1 to 439.1. The maximum values ​​of S1, S2 and S3 could reach 27.3, 67.6 and 10.2, respectively (Table 1). When the concentration of [C6mim]Br is fixed at 25wt.%, and the concentration of Na3C6H5O7 is changed to 15wt.% and 25wt.%, the distribution coefficient of the target molecule increases with the increase of Na3C6H5O7 concentration; in the absence of SC[4], the distribution coefficients of MA, Phe, Trp and Van can reach a maximum of 21.9, 3.1, 13.7 and 136.3, at which time, S1, S2 and S3 are 6.2, 44.0 and 10.0 respectively (Table 1); when containing 10wt.% SC[4], the distribution coefficient of MA increases from 5.2 to 9.7, the distribution coefficient of Phe increases from 1.1 to 3.5, the distribution coefficient of Trp increases from 13.0 to 28.1, the distribution coefficient of Van increases from 106.7 to 282.6, and the maximum values ​​of S1, S2 and S3 can reach 29.1, 80.7 and 10.1 respectively (Table 1).

[0055] Figure 3 It shows that at 25wt.% [C 10In the mim]Br / 20wt.%Na3C6H5O7 ATPS, when the concentration of SC[4] increased from 0wt.% to 10wt.%, the distribution coefficient of MA decreased from 10.0 to 7.0, the distribution coefficient of Phe remained unchanged at about 2, the distribution coefficient of Trp increased from 8.6 to 12.7, the distribution coefficient of Van increased from 17.5 to 112.5; S1 increased from 1.8 to 16.1, S2 increased from 8.3 to 80.4, and S3 increased from 2.0 to 8.9 (Table 1). When the concentration of Na3C6H5O7 was fixed at 20wt.%, changing [C 10 mim]Br concentration is 15wt.%, and as [C 10 With the increase of mim]Br concentration, the distribution coefficient of the target molecule increases; when containing 10wt.% SC[4], S1, S2, and S3 can reach a maximum of 39.4, 86.7, and 9.9 (Table 1). 10 When the mim]Br concentration was 25wt.%, the Na3C6H5O7 concentration was changed to 15wt.% and 25wt.%, and the distribution coefficient of the target molecule increased with the increase of the Na3C6H5O7 concentration; in the absence of SC[4], the distribution coefficients of MA, Phe, Trp and Van could reach a maximum of 27.9, 3.8, 21.4 and 215.2, at which time, S1, S2 and S3 were 7.7, 56.6 and 10.1 respectively (Table 1); when containing 5wt.% SC[4], the distribution coefficient of MA increased from 6.2 to 10.8, the distribution coefficient of Phe increased from 1.5 to 2.8, the distribution coefficient of Trp increased from 12.1 to 23.3, the distribution coefficient of Van increased from 87.7 to 315.7, and the maximum values ​​of S1, S2 and S3 could reach 29.2, 112.8 and 13.6 respectively (Table 1).

Claims

1. A method for selectively extracting vanillin using an ionic liquid / salt / sulfonylated calix[4]arene aqueous two-phase system, characterized in that: Specifically, the extract containing vanillin is added to the ionic liquid / salt / sulfonylated calix[4]arene aqueous two-phase system, mixed evenly, and centrifuged to completely separate the two phases. The upper phase is collected to obtain the extracted vanillin. The ionic liquid / salt / sulfonylated calix[4]arene aqueous two-phase system is [C n mim]Br / Na3C6H5O7 / SC[4] two-phase aqueous system, the [C n mim]Br / Na3C6H5O7 / SC[4] aqueous two-phase system uses deionized water as solvent, the concentration of ionic liquid is 15 wt.% ~35 wt.%, the concentration of Na3C6H5O7 is 15 wt.% ~25 wt.%, the concentration of sulfonylated calix[4]arene is 5 wt.% ~10 wt.%, and the ionic liquid is [C6mim]Br or [C 10 mim]Br, the structural formula of the sulfonylated calix[4]arene is: , the structural formula of [C6mim]Br is: ,[C 10 The structural formula of mim]Br is: .

2. The method according to claim 1, wherein In the ionic liquid / salt / sulfonylated calix[4]arene aqueous two-phase system, the concentration of the ionic liquid is 25 wt.% ~35 wt.%, the concentration of Na3C6H5O7 is 20 wt.% ~25 wt.%, and the concentration of the sulfonylated calix[4]arene is 5 wt.% ~10 wt.%.

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