A glutamine small molecule gel and a synthesis method and application thereof

Abstract

This invention discloses a glutamic acid amide-based small molecule gelling agent, its synthesis method, and its applications. The structure of the small molecule gel is shown in (I). The glutamic acid amide-based small molecule gelling agent of this invention is prepared by the following method: using L-glutamine protected by tert-butyloxycarbonyl and n-alkylamines of different chain lengths as starting materials, the target product can rapidly (3-5 minutes) coagulate soybean oil, gasoline, kerosene, diesel, liquid paraffin, refined oil, crude oil, decadecane, dodecane, tetradecane, and hexadecane, etc. It can also decolorize water-soluble pigments (Acid Red 289, Acid Red 73, Lithol Red BCA, Direct Dark Brown M, Acid Yellow 17, Acid Red 114, Alizarin Green, Azo Blue, Acid Violet 6B, Acid Black 24, and Direct Black 38, etc.).

Description

Technical Field

[0001] This invention relates to a gelling material, its synthesis method, and its applications, specifically to a glutamine-based small molecule gelling agent, its synthesis method, and its applications. This gelling agent can selectively gel in solvents such as soybean oil, gasoline, kerosene, diesel, liquid paraffin, crude oil, refined petroleum, decadecane, dodecane, tetradecane, and hexadecane. It can also decolorize water-soluble pigments (such as Acid Red 144 and Acid Black 24). The synthesis method optimizes the gelling properties by changing the carbon chain length. Background Technology

[0002] Small molecule organic gels are a class of materials that undergo a reversible solution-gel phase transition after being dissolved in an organic solvent by heating and then cooling. They form highly ordered molecular aggregates through non-covalent interactions. These materials have attracted considerable interest over the past few decades and are now widely used in oil spill recovery, water pollution treatment, mechanical lubrication, ion detection, nanocomposite materials, and 3D printing. Summary of the Invention

[0003] Objective of this invention: The objective of this invention is to provide an L-glutamine-based small molecule gelling agent that can selectively gel in solvents such as soybean oil, gasoline, kerosene, diesel, liquid paraffin, crude oil, refined petroleum, decadecane, dodecane, tetradecane, and hexadecane. This gelling agent can also decolorize water-soluble pigments (Acid Red 289, Acid Red 73, Lithol Red BCA, Direct Dark Brown M, Acid Yellow 17, Acid Red 114, Alizarin Green, Azo Blue, Acid Violet 6B, Acid Black 24, and Direct Black 38). Another objective of this invention is to provide a method for synthesizing the aforementioned gelling agent and its applications.

[0004] Technical solution: The glutamic acid amide-based small molecule gelling agent of the present invention has the general structural formula shown in (I):

[0005]

[0006] The synthesis method of glutamine-based small molecule gelling agents includes the following steps:

[0007] Boc-L-glutamine, fatty amine, N,N-diisopropylethylamine (DIPEA), and 2-(7-azabenzotriazole)-N,N,N′,N′-tetramethylurea hexafluorophosphate (HATU) were added sequentially to a reaction vessel and stirred with dichloromethane. After the reaction was complete, the pH was adjusted to acidic with HCl solution and then to alkaline with saturated NaHCO3 solution. The organic phase was extracted with an organic solvent, washed with saturated NaCl aqueous solution, concentrated, evaporated to dryness, and recrystallized to obtain the product.

[0008] The method for synthesizing the glutamine-based small molecule gelling agent, wherein the dichloromethane is dry dichloromethane.

[0009] The method for synthesizing the glutamine-based small molecule gelling agent, wherein the concentration of the HCl solution is 1.5–2.5 M.

[0010] The method for synthesizing the glutamine-based small molecule gelling agent, wherein adjusting the pH to acidic using HCl solution means adjusting the pH to 3-4.

[0011] The method for synthesizing the glutamine-based small molecule gelling agent, wherein adjusting the pH to alkaline using a saturated NaHCO3 solution, means adjusting the pH to 8-10.

[0012] The method for synthesizing the glutamine-based small molecule gelling agent, wherein the molar ratio of added Boc-protected L-glutamine: long-chain amine: DIPEA: HATU is 1:1~2:2~3:1~2.

[0013] The method for synthesizing the glutamine-based small molecule gelling agent, wherein the molar ratio of added Boc-protected L-glutamine: long-chain amine: DIPEA: HATU is 1:1.2:2.2:1.2.

[0014] The method for synthesizing the glutamine-based small molecule gelling agent, wherein the organic phase is extracted with dichloromethane.

[0015] The specific steps of recrystallization in the synthesis method of the glutamine-based small molecule gelling agent are as follows: the product obtained by rotary evaporation is dissolved in a small amount of ethyl acetate and then slowly added dropwise to a large amount of petroleum ether. A white solid precipitates out, and the solution becomes a milky white suspension. After filtration, the filtrate is discarded, and the solution is washed and dried.

[0016] The application of the glutamamide-based small molecule gelling agent in the preparation of organic solvent gelling agents. Preferably, the organic solvent includes soybean oil, gasoline, kerosene, diesel oil, liquid paraffin, refined petroleum float, crude oil, decadecane, dodecane, tetradecane, and hexadecane.

[0017] The application of the glutamate-based small molecule gelling agent in pigment decolorization. Preferably, the pigment includes Acid Red 289, Acid Red 73, Lithol Red BCA, Direct Dark Brown M, Acid Yellow 17, Acid Red 114, Alizarin Green, Azo Blue, Acid Violet 6B, Acid Black 24, and Direct Black 38.

[0018] Beneficial effects: Compared with the prior art, the present invention (1) designed a series of L-glutamine small molecule gelling agents, wherein the gelling factor G with a carbon chain length of 14 14It has good gelling ability for solvents such as soybean oil, gasoline, kerosene, diesel, liquid paraffin, crude oil, refined oil, decadecane, dodecane, tetradecane and hexadecane, and can also decolorize pigments (Acid Red 289, Acid Red 73, Lithol Red BCA, Direct Dark Brown M, Acid Yellow 17, Acid Red 114, Alizarin Green, Azo Blue, Acid Violet 6B, Acid Black 24 and Direct Black 38) dissolved in water. (2) The present invention demonstrates that obvious decolorization occurs through UV-Vis absorption tests of the gelling factor and its aqueous solutions of Acid Red 289, Acid Red 73, Lithol Red BCA, Direct Dark Brown M, Acid Yellow 17, Acid Red 114, Alizarin Green, Azo Blue, Acid Violet 6B, Acid Black 24 and Direct Black 38. (3) The present invention has a gelling factor G with a carbon chain length of 14. 14 It can selectively and rapidly solidify diesel in diesel / water solutions. (4) This invention utilizes G 14 Gel-forming factor and its infrared absorption spectral analysis in Acid Red 114 and Acid Black 24 gels, G 14 After gel formation in Acid Red 114 and Acid Black 24, the NH absorption peak on the amide bond showed a significant red shift, indicating that after gel formation, the amide bond in the gel factor molecule formed intermolecular hydrogen bonds, which restricted the stretching vibration amplitude of both molecules, causing a shift in their infrared characteristic absorption peaks. Attached Figure Description

[0019] Figure 1 It is G 14 The proton NMR spectrum;

[0020] Figure 2 It was during the G 14 Fourier transform infrared spectra of Acid Red 144 before and after;

[0021] Figure 3 It was during the G 14 Fourier transform infrared spectra of Acid Black 24 before and after;

[0022] Figure 4 Is it joining G? 14 UV-Vis absorption spectrum of Acid Red 289 over time;

[0023] Figure 5 Is it joining G? 14 UV-Vis absorption spectrum of Acid Red 73 over time;

[0024] Figure 6 Is it joining G? 14 UV-Vis absorption spectrum of Lithol Red BCA over time;

[0025] Figure 7 Is it joining G? 14The UV-Vis absorption spectrum of the dark brown M over time;

[0026] Figure 8 Is it joining G? 14 UV-Vis absorption spectrum of Acid Yellow 17 over time;

[0027] Figure 9 Is it joining G? 14 UV-Vis absorption spectrum of Acid Red 114 over time;

[0028] Figure 10 Is it joining G? 14 The UV-Vis absorption spectrum of alizarin green over time;

[0029] Figure 11 Is it joining G? 14 UV-Vis absorption spectrum of azo blue over time;

[0030] Figure 12 Is it joining G? 14 UV-Vis absorption spectrum of Acid Violet 6B over time;

[0031] Figure 13 Is it joining G? 14 UV-Vis absorption spectrum of Acid Black 24 over time;

[0032] Figure 14 Is it joining G? 14 The UV-Vis absorption spectrum of Direct Black 38 after changes over time;

[0033] Figure 15 G from left to right 14 Gel image of n-decane; G 14 gel image of n-dodecane;

[0034] Figure 16 G from left to right 14 Gel image of n-tetradecane; G 14 gel image of n-hexadecane;

[0035] Figure 17 It is G 14 Diesel rapid gelation diagram;

[0036] Figure 18 It is G 14 Amplitude-scan rheometry of diesel fuel rapid gel;

[0037] Figure 19 It is G 14 Frequency-scan rheometry of diesel fuel rapid gelation;

[0038] Figure 20 It is G14 Amplitude-scan rheometry of n-decane rapid gel;

[0039] Figure 21 It is G 14 Amplitude-scan rheometry of n-dodecane rapid gel;

[0040] Figure 22 It is G 14 Amplitude-scan rheometry of n-tetradecane rapid gel;

[0041] Figure 23 It is G 14 Amplitude scanning rheometry of hexadecane rapid gel. Detailed Implementation

[0042] Example 1: L-glutamine gelling agents with different chain lengths

[0043] Synthetic steps: Weigh 10 mmol of tert-butyloxycarbonyl (Boc)-protected L-glutamine into a round-bottom flask, add 20 mL of dry dichloromethane (DCM) and stir. Using a syringe, add 1.2 eq of a long-chain amine and 2.2 eq of DIPEA to the round-bottom flask and stir until dissolved. Finally, add 1.2 eq of HATU and stir overnight at room temperature. The next day, after the reaction is complete as determined by thin-layer chromatography, add an appropriate amount of water to the system, adjust the pH to approximately 3–4 with 2M HCl solution, and then adjust the pH to approximately 8–10 with saturated NaHCO3 solution. Extract the organic phase with dichloromethane, wash the organic phase with saturated NaCl solution, evaporate to dryness, concentrate, and recrystallize.

[0044] Recrystallization procedure: Take a 500mL round-bottom flask and add 350mL of petroleum ether; add a small amount of ethyl acetate to the product obtained by rotary evaporation, heat to dissolve it completely, and then slowly add it dropwise to the petroleum ether. At this time, a large amount of white solid precipitates in the flask, and the solution gradually turns into a white suspension; after the addition is complete, filter, wash the filter cake three times with petroleum ether, and dry to obtain the final gelling agent.

[0045]

[0046] After preparing a series of compounds of general formula I with n = 5, 7, 9, 11, 13, 15, their proton nuclear magnetic resonance spectra were analyzed, where G... 14 The detection results for (compounds with a carbon chain length of 14, i.e., n=13 in general formula I) are as follows: Figure 1 As shown.

[0047] Test Results (I)

[0048] To further explain the decolorization process of the gel in the pigment, Acid Red 144 was measured. Figure 2 ) and Acid Black 24 ( Figure 3 ) after joining G 14 Infrared absorption spectra of the sample before and after addition of G. In the infrared absorption spectrum of Acid Red 144, G was added... 14 The peak of the NH stretching vibration on the amide bond can be seen at 1652 cm⁻¹. -1 The carbonyl stretching vibration peak is at 1538 cm⁻¹. -1 Add 1% G 14 The NH stretching vibration peak on the amide bond is at 1630 cm⁻¹. -1 The carbonyl stretching vibration peak is at 1530 cm⁻¹ -1 In the infrared absorption spectrum of Acid Black 24, G was added... 14 The peak of the NH stretching vibration on the amide bond can be seen at 1695 cm⁻¹. -1 The carbonyl stretching vibration peak is at 1546 cm⁻¹. -1 Add 1% G 14 The NH stretching vibration peak on the amide bond is at 1690 cm⁻¹. -1 The carbonyl stretching vibration peak is at 1527 cm⁻¹. -1 After decolorization, the characteristic absorption peaks of NH and carbonyl groups on the amide bonds both showed a significant red shift. This indicates that intermolecular hydrogen bonds formed between the amide bonds in the gel factor molecules after decolorization, which restricted the amplitude of their stretching vibrations, causing the infrared characteristic absorption peaks to shift. This also proves that hydrogen bonds are the main driving force in the self-assembly process of the gel factor in removing pigments from water.

[0049] Test Result (II)

[0050] G was measured using ultraviolet-visible absorption spectroscopy. 14 Decolorization of different dyes

[0051] Experiment 1 used 1mg G 14 Add 2 mg / mL of Acid Red 289 aqueous solution and perform UV-Vis absorption spectroscopy testing. Take samples at 10 min, 60 min, 120 min, 200 min, 300 min, and 400 min to observe the decolorization.

[0052] Experiment 2 used 1mg G 14 Add 2 mg / mL of Acid Red 73 aqueous solution and perform UV-Vis absorption spectroscopy testing. Take samples at 10 min, 60 min, 120 min, 200 min, 300 min and 400 min to observe the decolorization.

[0053] Experiment 3 used 1mg G 14Add 2 mg / mL Rissol Red BCA aqueous solution and perform UV-Vis absorption spectroscopy. Take samples at 10 min, 60 min, 120 min, 200 min, 300 min and 400 min to observe the decolorization.

[0054] Experiment 4 used 1mg G 14 Add 2 mg / mL of Direct Dark Brown M aqueous solution and perform UV-Vis absorption spectroscopy testing. Take samples once at 10 min, 60 min, 120 min, 200 min, 300 min and 400 min to observe the decolorization.

[0055] Experiment 5 used 1mg G 14 Add 2 mg / mL of Acid Yellow 17 aqueous solution and perform UV-Vis absorption spectroscopy tests. Take samples at 10 min, 60 min, 120 min, 200 min, 300 min and 400 min to observe the decolorization.

[0056] Experiment 6 used 1mg G 14 Add 2 mg / mL of Acid Red 114 aqueous solution and perform UV-Vis absorption spectroscopy testing. Take samples at 10 min, 60 min, 120 min, 200 min, 300 min and 400 min to observe the decolorization.

[0057] Experiment 7 used 1mg G 14 Add 2 mg / mL alizarin green aqueous solution and perform UV-Vis absorption spectroscopy test. Take samples once at 10 min, 60 min, 120 min, 200 min, 300 min and 400 min to observe the decolorization.

[0058] Experiment 8 used 1mg G 14 Add 2 mg / mL azo blue aqueous solution and perform UV-Vis absorption spectroscopy testing. Take samples at 10 min, 60 min, 120 min, 200 min, 300 min and 400 min to observe the decolorization.

[0059] Experiment 9 used 1mg G 14 Add 2 mg / mL of Acid Violet 6B aqueous solution and perform UV-Vis absorption spectroscopy tests. Take samples at 10 min, 60 min, 120 min, 200 min, 300 min, and 400 min to observe the decolorization.

[0060] Experiment 10 uses 1mg G 14 Add 2 mg / mL of Acid Black 24 aqueous solution and perform UV-Vis absorption spectroscopy tests. Take samples at 10 min, 60 min, 120 min, 200 min, 300 min and 400 min to observe the decolorization.

[0061] Experiment 11 used 1mg G 14 Add 2 mg / mL of Direct Black 38 aqueous solution and perform UV-Vis absorption spectroscopy tests. Take samples at 10 min, 60 min, 120 min, 200 min, 300 min and 400 min to observe the decolorization.

[0062] Detailed data analysis

[0063] 1mgG was selected 14 UV-Vis absorption spectroscopy was performed after adding 2 mg / mL of Acid Red 289 aqueous solution. UV-Vis absorption curves were obtained at sampling times of 10 min, 60 min, 120 min, 200 min, 300 min, 400 min, and 0-400 min. Figure 4 The data shows that, with G 14 With the addition of [a specific ingredient], the absorption intensity of Acid Red 289 gradually decreased until it was completely decolorized after 400 minutes. Experiments show that G [a specific ingredient]... 14 Gel agents are very effective at removing Acid Red 289 from water.

[0064] 1mgG was selected 14 UV-Vis absorption spectroscopy was performed after adding 2 mg / mL Acid Red 73 aqueous solution. UV-Vis absorption curves were obtained at sampling times of 10 min, 60 min, 120 min, 200 min, 300 min, 400 min, and 0-400 min. Figure 5 The data shows that, with G 14 With the addition of [a specific ingredient], the absorption intensity of Acid Red 73 gradually decreased until it was completely decolorized after 400 minutes. Experiments show that G [a specific ingredient]... 14 Gel agents are very effective at removing Acid Red 73 from water.

[0065] 1mgG was selected 14 UV-Vis absorption spectroscopy was performed after adding 2 mg / mL ribsol red BCA aqueous solution. UV-Vis absorption curves were obtained at sampling times of 10 min, 60 min, 120 min, 200 min, 300 min, 400 min, and 0-400 min. Figure 6 The data shows that, with G 14 With the addition of [a specific ingredient], the absorption intensity of Lithol Red BCA gradually decreased until it was completely decolorized after 400 minutes. Experiments show that G [a specific ingredient]... 14 Gel agents are very effective at removing Lisol Red BCA from water.

[0066] 1mgG was selected 14UV-Vis absorption spectroscopy was performed after adding 2 mg / mL of direct dark brown M aqueous solution. UV-Vis absorption curves were obtained at sampling times of 10 min, 60 min, 120 min, 200 min, 300 min, 400 min, and 0-400 min. Figure 7 The data shows that, with G 14 With the addition of [a specific ingredient], the absorption intensity of the direct dark brown M gradually decreased until it was completely decolorized after 400 minutes. Experiments show that G [a specific ingredient]... 14 Gel agents are very effective for removing direct dark brown M from water.

[0067] 1mgG was selected 14 UV-Vis absorption spectroscopy was performed after adding 2 mg / mL of Acid Yellow 17 aqueous solution. UV-Vis absorption curves were obtained at sampling times of 10 min, 60 min, 120 min, 200 min, 300 min, 400 min, and 0-400 min. Figure 8 The data shows that, with G 14 With the addition of [a specific ingredient], the absorption intensity of Acid Yellow 17 gradually decreased until it was completely decolorized after 400 minutes. Experiments show that G [a specific ingredient]... 14 Gel agents are very effective at removing Acid Yellow 17 from water.

[0068] 1mgG was selected 14 UV-Vis absorption spectroscopy was performed after adding 2 mg / mL of Acid Red 114 aqueous solution. UV-Vis absorption curves were obtained at sampling times of 10 min, 60 min, 120 min, 200 min, 300 min, 400 min, and 0-400 min. Figure 9 The data shows that, with G 14 With the addition of [a specific ingredient], the absorption intensity of Acid Red 114 gradually decreased until it was completely decolorized after 400 minutes. Experiments show that G [a specific ingredient]... 14 Gel agents are very effective at removing Acid Red 114 from water.

[0069] 1mgG was selected 14 UV-Vis absorption spectroscopy was performed after adding 2 mg / mL alizarin green aqueous solution. UV-Vis absorption curves were obtained at sampling times of 10 min, 60 min, 120 min, 200 min, 300 min, 400 min, and 0-400 min. Figure 10 The data shows that, with G 14 With the addition of [a specific ingredient], the absorption intensity of alizarin green gradually decreased until it was completely decolorized after 400 minutes. Experiments show that G [a specific ingredient]... 14 Gel agents are very effective at removing alizarin green from water.

[0070] 1mgG was selected 14UV-Vis absorption spectroscopy was performed with 2 mg / mL azo blue aqueous solution. UV-Vis absorption curves were obtained at sampling times of 10 min, 60 min, 120 min, 200 min, 300 min, 400 min, and 0-400 min. Figure 11 The data shows that, with G 14 With the addition of [agent name], the absorption intensity of azo blue gradually decreased until it was completely decolorized after 400 minutes. Experiments show that G [agent name]... 14 Gel agents are very effective at removing azo blue from water.

[0071] 1mgG was selected 14 UV-Vis absorption spectroscopy was performed after adding 2 mg / mL of Acid Violet 6B aqueous solution. UV-Vis absorption curves were obtained at sampling times of 10 min, 60 min, 120 min, 200 min, 300 min, 400 min, and 0-400 min. Figure 12 The data shows that, with G 14 With the addition of [agent name], the absorption intensity of Acid Violet 6B gradually decreased until it was completely decolorized after 400 minutes. Experiments show that G [agent name]... 14 Gel agents are often effective in removing Acid Violet 6B from water.

[0072] 1mgG was selected 14 UV-Vis absorption spectroscopy was performed after adding 2 mg / mL of Acid Black 24 aqueous solution. UV-Vis absorption curves were obtained at sampling times of 10 min, 60 min, 120 min, 200 min, 300 min, 400 min, and 0-400 min. Figure 13 The data shows that, with G 14 With the addition of [a specific ingredient], the absorption intensity of Acid Black 24 gradually decreased until it was completely decolorized after 400 minutes. Experiments show that G [a specific ingredient]... 14 Gel agents are very effective in removing acidic black 24 from water.

[0073] 1mgG was selected 14 UV-Vis absorption spectroscopy was performed after adding 2 mg / mL of Direct Black 38 aqueous solution. UV-Vis absorption curves were obtained at sampling times of 10 min, 60 min, 120 min, 200 min, 300 min, 400 min, and 0-400 min. Figure 14 The data shows that, with G 14 With the addition of [a specific ingredient], the absorption intensity of Direct Black 38 gradually decreased until it was completely decolorized after 400 minutes. Experiments show that G [a specific ingredient]... 14 Gel agents are very effective in removing Direct Black 38 from water.

[0074] Test Results (III)

[0075] Table 1 shows the results of testing the synthesized gelling factor G. 14 The gelation properties in different solvents and the minimum gel concentration for gel formation were tested and found that G 14 It can be used in n-decane, n-dodecane, n-tetradecane, and n-hexadecane ( Figure 15 , Figure 16 A stable gel is formed in the process.

[0076] Table 1: Gel Agent G 14 Gel properties in various solvents

[0077]

[0078]

[0079] P=precipitation; S=soluble; I=insoluble.

[0080] Rheological properties are important parameters for investigating the creep properties of materials, and the rheological data of organic gels are very important in practical applications, as they can show the mechanical strength of gel materials. Figure 17 It is gelling agent G 14 A diagram showing the rapid gel formation in diesel fuel. Figure 18 19 shows gelling agent G 14 Amplitude and frequency scan results of the rapid gel formed in diesel fuel. Figure 20-23 It is G 14 Amplitude scanning rheograms of rapid gels formed in n-decane, n-dodecane, n-tetradecane, and n-hexadecane, respectively.

[0081] With a fixed frequency of 1 Hz and an amplitude scan with stress variations ranging from 0.01% to 100%, the curves represent the trends in storage modulus G' and loss modulus G”. When the storage modulus G' is greater than the loss modulus G”, the system exhibits solid characteristics. As the strain increases, the system deforms, causing energy loss to be converted into heat energy, and the loss modulus G” becomes greater than the storage modulus G', indicating that the system exhibits liquid rheological properties. The changes in G’ can be observed from the cross-curve changes in the figure. 14 The rapidly formed gel in diesel fuel exhibited a change in rheological properties from solid to liquid; under constant strain of 0.05% rad / s and varying frequency, the test curve G' was consistently greater than G", consistent with the characteristics of gel solid rheology. Amplitude and frequency scanning results showed that G... 14 The gelling agent formed a true gel in diesel fuel, and the gel exhibited strong stability. Gel factor G 14 The rapid gel formed in diesel fuel has a relatively high storage modulus, indicating that the gel formed has higher mechanical strength and better gelation effect.

[0082] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. For those skilled in the art, the present invention can have various changes and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. The use of glutamine-based small molecule gelator in removing pigments from water, characterized in that: The structure is shown in (Ⅰ): ​ （Ⅰ） The pigment is selected from one or more of Acid Red 289, Acid Red 73, Lithol Red BCA, Direct Dark Brown M, Acid Yellow 17, Acid Red 114, Alizarin Green, Azo Blue, Acid Violet 6B, Acid Black 24, and Direct Black 38.

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