Photocatalytic synthesis of stilbene, porous polySchiff base materials and dye adsorption applications

Abstract

This invention relates to the fields of dye adsorption and decontamination, and water purification technology. It provides a photocatalytic synthesis of porous polySchiff base materials from styrene and their application in dye adsorption. The polySchiff base provided by this invention is produced by dissolving bis(amino) rigid styrene (as shown in Formula 2) in a chloroform solution and subjecting it to a 365nm ultraviolet lamp (60mW / cm²). ‑2 The resulting brown or red solid, obtained by irradiation and filtration, is polySchiff base. The required irradiation time varies depending on the concentration; 10... ‑5 Polymerization at mol / L can be completed in just a few seconds. Three solvents, DMSO, THF, and CHCl3, were screened, and CHCl3 was found to have the highest polymerization rate. Furthermore, the obtained polySchiff base can be degraded in HCl and D / L-CSA acid environments.

Description

Technical Field

[0001] This invention belongs to the field of dye adsorption and decontamination technology and water purification technology, and particularly relates to the photocatalytic synthesis of porous polySchiff base materials from stilbene and their dye adsorption applications. Background Technology

[0002] The synthesis of conventional polySchiff bases typically requires relatively strict conditions, such as acid-base control, an anhydrous solvent environment, or continuous water removal using a separator, as well as relatively long reaction times. In contrast, the method provided by this invention only requires dissolving the polymer precursor in CHCl3 and irradiating it with a 365nm ultraviolet lamp. Gram-scale polymerization of the precursor can be achieved within 1 hour. After the photocatalytic reaction, only filtration, washing, and drying are needed to obtain the target polySchiff base product. This method is simple, efficient, and has significant advantages over traditional methods.

[0003] Simple and efficient removal of micropollutants from water is crucial for water resource reuse. Many traditional chemical, physical, and biological treatment methods, such as ozonation, electrochemical methods, precipitation, solar-assisted photocatalytic degradation, and nanofiltration, have been used to remove dyes from wastewater. Adsorption is considered the most economical and effective method for removing dyes from wastewater, as it can be carried out at room temperature without producing any harmful byproducts. Therefore, developing photocatalytic synthesis of highly conjugated polySchiff bases for dye removal from wastewater is of great significance. Ultimately, the application of polySchiff bases in the adsorption and removal of various dyes, including Direct Blue 86, Methyl Orange, Methyl Red, Neutral Red, Saffron T, and Rhodamine B, was realized. Summary of the Invention

[0004] The first objective of this invention is to improve upon existing polymerization techniques by providing a method for the photocatalytic synthesis of porous polySchiff bases. This invention allows the polySchiff base target product to be obtained simply by filtration, washing, and drying after the photocatalytic reaction. Furthermore, the polySchiff base material exhibits strong adsorption capacity for Direct Blue 86, Methyl Orange, Methyl Red, Saffron T, and Rhodamine B, making it suitable for applications such as dye adsorption and decontamination, and water purification.

[0005] This invention is achieved through photocatalytic synthesis of porous polySchiff base materials from stilbene, comprising porous polySchiff base materials, wherein the porous polySchiff base materials are synthesized using the following methods:

[0006]

[0007] Where n is approximately 711.

[0008] (E)-7, (E)-8, and (E)-9 were selected and dissolved in CHCl3, and then tested with a 365 nm UV lamp (60 mW cm⁻¹). -2 The irradiation reactions yielded 10, 11, and 12, respectively.

[0009] Preferably, the porous polySchiff base material is synthesized by applying light.

[0010] Preferably, the synthesis of the monomer molecule (E)-7 of the porous polySchiff base material includes the following steps:

[0011] (1) Under a nitrogen atmosphere and with vigorous stirring, titanium tetrachloride was slowly added to a THF suspension of zinc powder. After reflux and stirring for 2 hours, the mixture was cooled to room temperature to obtain a black suspension. Then, solid 6-bromo-1-indanone was added to the black suspension and stirred under reflux. After the reaction was completed, it was quenched with saturated ammonium chloride aqueous solution and extracted with CHCl3. The organic phases were combined and concentrated, the precipitate was filtered off and dried to obtain a pale yellow solid (E)-1.

[0012] (2) Compound (E)-1, palladium acetate, DPPF, and sodium tert-butoxide were added to a Shrek flask and subjected to three vacuum / N2 cycles. Degassed toluene was then added, followed by the addition of benzophenone imine, followed by stirring and reflux. After the reaction was complete, the mixture was cooled to room temperature and diluted with water. The aqueous layer was extracted with CHCl3, and the combined organic phases were dried over Na2SO4 and concentrated. Column chromatography yielded a yellow solid imine intermediate, which was redissolved in THF. 2M HCl was added, and after stirring for 1.5 hours, a saturated aqueous solution of KHCO3 (pH ~10) was added. The mixture was extracted with ethyl acetate, and the combined organic phases were dried over Na2SO4 and concentrated. The product was washed with Et2O and dried to give a yellow solid (E)-7.

[0013] Preferably, the preparation method of the porous polySchiff base material is as follows: monomer molecules (E)-7, (E)-8 and (E)-9 are respectively dissolved in CHCl3, and the solution is prepared using a 365nm ultraviolet lamp (60mWcm). -2 Irradiation, filtration, washing and drying yielded brown or red polySchiff base materials 10, 11 and 12, respectively.

[0014] Preferably, the porous polySchiff base material is used to measure the structural information of its photopolymerized Schiff base material using 1H NMR spectroscopy.

[0015] Preferably, the porous polySchiff base material is used to measure the structural information of its photopolymerized Schiff base material using infrared spectroscopy.

[0016] Preferably, the degree of polymerization of the porous polySchiff base material is measured using the GPC method.

[0017] Preferably, the porous polySchiff base material has its ultraviolet-visible absorption spectrum measured using an ultraviolet spectrophotometer.

[0018] Preferably, the porous polySchiff base material is tested for its adsorption capacity for dyes Direct Blue 86, Methyl Orange, Methyl Red, Saffron T, and Rhodamine B.

[0019] The photocatalytic synthesis of porous polySchiff base materials from stilbene is applied to dye adsorption, and is suitable for dye adsorption and decontamination, water purification, and other fields.

[0020] Weigh out a certain mass of Direct Blue 86, Methyl Orange, Methyl Red, Saffron T, and Rhodamine B, dissolve them separately in water, and add an equal mass of the aforementioned highly conjugated polySchiff bases. Mix thoroughly and stir for 3 minutes. Filter to remove the polySchiff bases adsorbing the dyes, thereby obtaining purified water.

[0021] Compared with the prior art, the embodiments of this application have the following main advantages:

[0022] The preparation process of this invention is simple and easy to purify. The method for synthesizing polySchiff bases is simple and efficient. The resulting highly conjugated polySchiff bases exhibit rapid and efficient adsorption properties for a variety of dyes. Attached Figure Description

[0023] Figure 1 This is the 1H NMR spectrum of compound (E)-1 in deuterated CDCl3;

[0024] Figure 2 This is the 1H NMR spectrum of compound (Z)-1 in deuterated CDCl3;

[0025] Figure 3 This is the 1H NMR spectrum of compound (E)-3 in deuterated CDCl3;

[0026] Figure 4 This is the 1H NMR spectrum of compound (Z)-3 in deuterated CDCl3;

[0027] Figure 5 This is the 1H NMR spectrum of compound (E)-5 in deuterated CDCl3;

[0028] Figure 6 This is the 1H NMR spectrum of compound (Z)-5 in deuterated CDCl3;

[0029] Figure 7 This is the carbon NMR spectrum of compound (E)-7 in deuterated CDCl3;

[0030] Figure 8 This is the 1H NMR spectrum of compound (E)-7 in deuterated DMSO;

[0031] Figure 9 This is the 1H NMR spectrum of compound (Z)-7 in deuterated CDCl3;

[0032] Figure 10 This is the 1H NMR spectrum of compound (Z)-7 in deuterated DMSO;

[0033] Figure 11 This is the 1H NMR spectrum of compound (E)-8 in deuterated CDCl3;

[0034] Figure 12 This is the 1H NMR spectrum of compound (E)-8 in deuterated DMSO;

[0035] Figure 13 This is the 1H NMR spectrum of compound (E)-9 in deuterated CDCl3;

[0036] Figure 14 This is the 1H NMR spectrum of compound (E)-9 in deuterated DMSO;

[0037] Figure 15 This is the 1H NMR spectrum of compound 10 in deuterated DMSO;

[0038] Figure 16 This is the 1H NMR spectrum of compound 11 in deuterated DMSO;

[0039] Figure 17 This is the 1H NMR spectrum of compound 12 in deuterated DMSO;

[0040] Figure 18 This is the 1H NMR spectrum of compound M in deuterated DMSO;

[0041] Figure 19 This is the carbon NMR spectrum of compound 10 in deuterated CD3OD;

[0042] Figure 20 This is the 1H NMR spectrum of compound (E)-7 in deuterated CDCl3 as a function of 365 nm light exposure time;

[0043] Figure 21 This is the 1H NMR spectrum of compound (Z)-7 in deuterated CDCl3 as a function of 365 nm light exposure time;

[0044] Figure 22 This is the 1H NMR spectrum of compound (E)-8 in deuterated CDCl3 as a function of 365 nm light exposure time;

[0045] Figure 23 This is the 1H NMR spectrum of compound (E)-9 in deuterated CDCl3 as a function of 365 nm light exposure time;

[0046] Figure 24 This is the 1H NMR spectrum of compound M in deuterated CDCl3 as a function of 365nm illumination time;

[0047] Figure 25 This is a comparison of the 1H NMR spectra of compounds (E)-7, (Z)-7, M, and 10 in deuterated DMSO;

[0048] Figure 26 This is a comparison of the infrared absorption spectra of compounds (E)-7 and 10;

[0049] Figure 27 This is a comparison of the infrared absorption spectra of compounds (E)-8 and 11;

[0050] Figure 28 This is a comparison of the infrared absorption spectra of compounds (E)-9 and 12;

[0051] Figure 29 This is the GPC analysis chromatogram of compound 10;

[0052] Figure 30 The UV absorption of compound 10 before and after adsorption of DB-86, MR, MR, ST, MO, and RhB is compared.

[0053] Figure 31 These are SEM images of compounds (E)-7, (E)-8, (E)-9, 10, 11 and 12; Detailed Implementation

[0054] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.

[0055] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0056] A method for synthesizing highly conjugated polySchiff bases is shown in Formula 1:

[0057]

[0058] Where n is approximately 711. (E)-7, (E)-8, and (E)-9 were selected and dissolved in CHCl3, respectively, and tested under a 365 nm UV lamp (60 mW cm⁻¹). -2 The irradiation reactions yielded 10, 11, and 12, respectively.

[0059] Secondly, the present invention provides a method for synthesizing the above-mentioned polySchiff base precursor, specifically:

[0060] Step (1): Under a nitrogen atmosphere and with vigorous stirring, titanium tetrachloride was slowly added to a THF suspension of zinc powder. After stirring under reflux for 2 hours and cooling to room temperature, a black suspension was obtained. Then, solid 6-bromo-1-indanone was added to the black suspension and stirred under reflux. After the reaction was completed, it was quenched with saturated ammonium chloride aqueous solution and extracted with CHCl3. The organic phases were combined and concentrated, the precipitate was filtered off and dried to obtain a pale yellow solid (E)-1; the filtrate was purified by silica gel column chromatography to obtain (Z)-1.

[0061] In step (2), compound (E)-1, palladium acetate, DPPF, and sodium tert-butoxide were added to a Shrek flask and subjected to three vacuum / N2 cycles. Degassed toluene was then added, followed by the addition of benzophenone imine, followed by stirring and reflux. After the reaction was complete, the mixture was cooled to room temperature and diluted with water. The aqueous layer was extracted with CHCl3, and the combined organic phases were dried and concentrated with Na2SO4. FC(Al2O3) yielded a yellow solid imine intermediate, which was redissolved in THF. 2M HCl was added, and after stirring for 1.5 hours, the solution was made alkaline by adding a saturated KHCO3 aqueous solution (pH ~10). The mixture was extracted with ethyl acetate, and the combined organic phases were dried and concentrated with Na2SO4. The product was washed with Et2O and dried to give a yellow solid (E)-7.

[0062] Thirdly, this invention provides the application of the aforementioned highly conjugated polySchiff base as a dye adsorption and decontamination agent. A certain mass of Direct Blue 86, Methyl Orange, Methyl Red, Neutral Red, Saffron T, and Rhodamine B are weighed and dissolved separately in water. 10% by mass of the aforementioned highly conjugated polySchiff base is added, and the mixture is stirred for 3 minutes after thorough mixing. The polySchiff base, having adsorbed the dye, is removed by filtration, thereby obtaining purified water.

[0063] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0064] Example 1: Synthesis of polySchiff base 10:

[0065] Step (1), Synthesis of compound (E)-1

[0066]

[0067] Zinc powder (5.898 g, 90.21 mmol) was added to a 250 mL three-necked Shrek flask. After three vacuum / N2 cycles, 75 mL of anhydrous THF was added using a syringe. Titanium tetrachloride (4.9 mL, 45 mmol) was slowly injected into the THF suspension of zinc powder under vigorous stirring. The solution was heated to reflux and stirred for 2 hours. After cooling to room temperature, a black suspension was obtained. Solid 6-bromo-1-indanone (4.76 g, 22.55 mmol) was added to the black suspension and stirred to reflux. After the reaction was completed, it was quenched with saturated ammonium chloride aqueous solution (50 mL) and extracted with CHCl3 (3 × 100 mL). The organic phases were combined and concentrated. The precipitate was filtered off and dried to give a pale yellow solid (E)-1 (yield 63.5%). 1 ¹H NMR (500MHz, CDCl₃) δ 7.69 (s, ¹H), 7.32 (d, J = 7.9 Hz, ¹H), 7.19 (d, J = 7.9 Hz, ¹H), 3.14 (d, J = 7.1 Hz, 2H), 3.10–3.05 (m, 2H). See [reference needed for ¹H NMR spectrum]. Figure 1 .

[0068] Step (2), Synthesis of compound (E)-7

[0069]

[0070] Compound (E)-1 (960 mg, 2.46 mmol), palladium acetate (44 mg, 0.2 mmol), DPPF (136 mg, 0.25 mmol), and sodium tert-butoxide (473 mg, 4.92 mmol) were added to a 250 mL three-necked Shrek flask and subjected to three vacuum / N2 cycles. Degassed toluene was then added, followed by the addition of benzophenone imine, followed by stirring and reflux. After the reaction was complete, the mixture was cooled to room temperature and diluted with water. The aqueous layer was extracted with CHCl3 (3 × 25 mL), and the combined organic phases were dried over Na2SO4 and concentrated. Column chromatography (Al2O3, DCM:PE = 1:1) yielded a yellow solid imine intermediate, which was redissolved in THF. 50 mL of 2M HCl was added, and after stirring for 1.5 hours, a saturated aqueous solution of KHCO3 (pH ~10) was added. The mixture was extracted with ethyl acetate (3 × 50 mL), and the combined organic phases were dried over Na2SO4 and concentrated. The product was washed with Et2O and dried to give a yellow solid (E)-7 (yield 86.4%). 1¹H NMR (500MHz, CDCl₃) δ 7.10 (d, J = 7.9 Hz, 2H), 6.97 (d, J = 1.9 Hz, 2H), 6.58 (dd, J = 7.9, 2.1 Hz, 2H), 3.62 (s, 4H), 3.18–3.09 (m, 4H), 3.00 (dd, J = 7.8, 4.8 Hz, 4H). See [reference needed for ¹H NMR spectrum]. Figure 7 .

[0071] Step (3), Synthesis of PolySchiff Base 10

[0072]

[0073] Add (E)-7 (1 g, 3.814 mmol) to a 250 mL single-necked flask, dissolve in 100 mL of CHCl3, stir constantly and apply a 365 nm UV lamp (60 mW cm⁻¹). -2 Irradiate for 1 hour to react. After the reaction is complete, filter, wash and dry to obtain the target poly-Schiff base product (yield 96.8%). 1 H NMR (500MHz, DMSO) δ9.93 (s, 4H), 7.62 (s, 2H), 7.44 (d, J = 8.0Hz, 2H), 7.19 (d, J = 7.9Hz, 2H), 3.12 (s, 8H). 13 C10 NMR (126MHz, CD3OD) δ 149.39, 145.66, 137.39, 130.93, 127.51, 122.73, 119.93, 33.05, 31.53. (See C10 NMR spectrum for details.) Figure 15 The carbon NMR spectrum is shown below. Figure 19 .

[0074] Example 2: Study on the properties of dyes adsorbed by polySchiff base 10:

[0075] PolySchiff base 10 was prepared by the method in Example 1. 1 mg each of Direct Blue 86, Methyl Orange, Methyl Red, Neutral Red, Saffron T, and Rhodamine B were weighed and dissolved in 10 ml of water. 10% (w / w) of polySchiff base 10 was added, and the mixture was stirred for 3 min after thorough mixing. The polySchiff base that had adsorbed the dye was removed by filtration, thus obtaining purified water.

[0076] According to the ultraviolet spectra, the intensity of the characteristic absorption peaks in the ultraviolet spectra of various dye solutions after being adsorbed by polySchiff base 10 decreased significantly, and the appearance color changed from the original color of the dye aqueous solution to colorless or light yellow.

[0077] It should be noted that, for the sake of simplicity, the foregoing embodiments are all described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to the present invention. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0078] It should be understood that the disclosed apparatus can be implemented in other ways, given the several embodiments provided in this application. For example, the apparatus embodiments described above are merely illustrative. For instance, the division of units described above may be implemented in other ways in practice. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or communication connections shown or discussed may be through some interfaces; indirect coupling or communication connections between devices or units may be telecommunications or other forms.

[0079] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0080] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on these embodiments, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still combine, add, delete, or otherwise adjust the features of the various embodiments of the present invention according to the circumstances without conflict or creative effort, thereby obtaining different technical solutions that do not fundamentally depart from the concept of the present invention. These technical solutions also fall within the scope of protection of the present invention.

Claims

1. A porous polySchiff base material synthesized by photocatalysis of stilbene, characterized in that, This includes porous polySchiff base materials, which are synthesized using the following methods: Formula 1 Where n is 711; The porous polySchiff base material is prepared by: selecting monomer molecules (E)-7, (E)-8, and (E)-9, dissolving them in CHCl3, and then using a 365 nm, 60 mW cm⁻¹ thermogravimetric analyzer. -2 After being irradiated with ultraviolet light, filtered, washed, and dried, brown or red polySchiff base materials 10, 11, and 12 were obtained, respectively.

2. The porous polySchiff base material for photocatalytic stilbene synthesis as described in claim 1, characterized in that, The synthesis of the monomer molecule (E)-7 of the porous polySchiff base material includes the following steps: (1) Under N2 atmosphere and vigorous stirring, titanium tetrachloride was slowly added to the THF suspension of zinc powder; after reflux and stirring for 2 hours, it was cooled to room temperature to obtain a black suspension. Then, solid 6-bromo-1-indanone was added to the black suspension and stirred and refluxed. After the reaction was completed, it was quenched with saturated ammonium chloride aqueous solution and extracted with CHCl3. The organic phases were combined and concentrated, the precipitate was filtered out and dried to obtain a pale yellow solid (E)-1. (2) Compound (E)-1, palladium acetate, DPPF and sodium tert-butoxide were added to a Shrek flask and subjected to three vacuum / N2 cycles. Then degassed toluene was added, and finally benzophenone imine was added and stirred under reflux. After the reaction was completed, the mixture was cooled to room temperature and diluted with water. The aqueous layer was extracted with CHCl3, and the combined organic phases were dried and concentrated with Na2SO4. The yellow solid imine intermediate was obtained by column chromatography and redissolved in THF. 2M HCl was added and stirred for 1.5 hours. Then, a saturated KHCO3 aqueous solution with pH 10 was added. The mixture was extracted with ethyl acetate, and the combined organic phases were dried and concentrated with Na2SO4. The product was washed with Et2O and dried to obtain the yellow solid (E)-7.

3. The application of the porous polySchiff base material synthesized by photocatalysis of stilbene as described in any one of claims 1-2 in dye adsorption, characterized in that, Suitable for dye adsorption and decontamination, and water purification.

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