阅读说明：本技术 一种凝胶乳液的制备方法及其模板化制备低密度荧光多孔金属配合物材料 (Preparation method of gel emulsion and templated preparation of low-density fluorescent porous metal complex material ) 是由 薛敏 刘晓翠 孙平 李朋娜 于 2021-01-15 设计创作，主要内容包括：本发明公开了一种凝胶乳液的制备方法及其模板化制备低密度荧光多孔金属配合物材料,将芳香羧酸型胆固醇衍生物作为有机配体溶于油相形成的溶液,与硝酸铽、硝酸铕等金属盐溶于水相形成的溶液相混合,利用有机配体和金属离子在油水界面的原位自组装反应形成的配合物作稳定剂,得到了W/O型的凝胶乳液,此凝胶乳液具有可逆的破坏-恢复的触变性能。当油相为可聚合单体(如苯乙烯)时,此类凝胶乳液可作为模板,通过油相的引发聚合制备得到低密度荧光多孔金属配合物材料,室温下即可干燥,不需要超临界干燥、冷冻干燥等一些高耗能的手段和大型专业设备,具有制备简单、材料性能优异、方便加工等特点,易于实现大规模工业化生产。(The invention discloses a preparation method of gel emulsion and a low-density fluorescent porous metal complex material prepared by template preparation, aromatic carboxylic acid type cholesterol derivative is taken as a solution formed by dissolving an organic ligand in an oil phase, the solution is mixed with a solution formed by dissolving metal salts such as terbium nitrate, europium nitrate and the like in a water phase, and a complex formed by in-situ self-assembly reaction of the organic ligand and metal ions at an oil-water interface is taken as a stabilizer to obtain W/O type gel emulsion, wherein the gel emulsion has reversible damage-recovery thixotropic property. When the oil phase is polymerizable monomer (such as styrene), the gel emulsion can be used as a template, the low-density fluorescent porous metal complex material can be prepared by initiating polymerization of the oil phase, and can be dried at room temperature without supercritical drying, freeze drying and other high-energy-consumption means and large-scale professional equipment, so that the preparation method has the characteristics of simplicity in preparation, excellent material performance, convenience in processing and the like, and is easy to realize large-scale industrial production.)

1. A method for preparing a gel emulsion, comprising: dissolving an organic ligand into an organic solvent immiscible with water at 50-80 ℃, dissolving terbium nitrate or europium nitrate into distilled water, and mixing and stirring the two solutions to form a gel emulsion; in the gel emulsion, the mass ratio of terbium nitrate or europium nitrate to the organic ligand to the water-immiscible organic solvent is 1: 2-5: 90-400, and distilled water accounts for 50-95% of the total mass of the distilled water and the organic solvent;

the structural formula of the organic ligand is shown as follows:

wherein n is 4, 6, 8 or 10.

2. The method for preparing a gel emulsion according to claim 1, characterized in that: the mass ratio of terbium nitrate or europium nitrate, the organic ligand and the water-immiscible organic solvent in the gel emulsion is 1: 3.5-4.5: 100-300, and the distilled water accounts for 70-85% of the total mass of the distilled water and the organic solvent.

3. The method for preparing a gel emulsion according to claim 1, characterized in that: and the organic ligand is dissolved in an organic solvent immiscible with water at the temperature of 65-75 ℃.

4. The method for preparing a gel emulsion according to any one of claims 1 to 3, characterized in that: the organic solvent immiscible with water is any one of benzene, toluene, p-xylene and styrene.

5. A low-density fluorescent porous metal complex material prepared by gel emulsion templating is characterized in that: in the preparation process of the gel emulsion of claim 1, the organic solvent immiscible with water is styrene, an organic ligand, an initiator and a cross-linking agent are dissolved in the styrene at 50-80 ℃, terbium nitrate or europium nitrate is dissolved in distilled water, the two solutions are mixed and stirred to form a gel emulsion containing the initiator and the cross-linking agent, the gel emulsion is polymerized for 20-24 hours at 50-80 ℃, and the gel emulsion is dried at room temperature to prepare the low-density fluorescent porous metal complex material;

in the gel emulsion, the mass ratio of terbium nitrate or europium nitrate, the organic ligand, the initiator, the cross-linking agent and the styrene is 1: 2-5: 10-20: 20-50: 90-400, and the distilled water accounts for 50-95% of the total mass of the distilled water and the styrene.

6. The gel emulsion templated preparation low-density fluorescent porous metal complex material of claim 5, wherein: the mass ratio of terbium nitrate or europium nitrate, organic ligand, initiator, cross-linking agent and styrene in the gel emulsion is 1: 3.5-4.5: 10-15: 30-40: 100-300, and the distilled water accounts for 70-85% of the total mass of the distilled water and the styrene.

7. The gel emulsion templated preparation low-density fluorescent porous metal complex material of claim 5, wherein: the organic ligand, the initiator and the cross-linking agent are dissolved in styrene at the temperature of 60-70 ℃.

8. The gel emulsion templated preparation low-density fluorescent porous metal complex material of claim 5, wherein: polymerizing the gel emulsion containing the initiator and the cross-linking agent at 65-70 ℃ for 24 hours.

9. The gel emulsion templating preparation low-density fluorescent porous metal complex material according to any one of claims 5 to 8, characterized in that: the initiator is azobisisobutyronitrile, and the crosslinking agent is divinylbenzene.

Technical Field

The invention belongs to the technical field of preparation of gel emulsion, and particularly relates to a method for preparing gel emulsion by using a complex formed by in-situ self-assembly reaction of an organic ligand and metal ions at an oil-water interface as a stabilizer, and a low-density porous metal complex material prepared by using the gel emulsion as a template.

Background

Gel emulsions are three-component systems formed from a stabilizer, a dispersed phase (internal phase) and a continuous phase (external phase) that are gel-like in appearance. Gel emulsion systems are also known as ultra (high) concentrated emulsions (high), biliquid foams (biliquid foams), viscous emulsions (adhesive emulsions), structured continuous phase emulsions (emulsions with structured continuous phase). For the conventional gel emulsion, when the volume fraction of the dispersed phase is more than 74%, the droplets of the dispersed phase are not spherical but irregular polyhedral due to high packing, so that the gel emulsion system can be regarded as being composed of a plurality of irregular polyhedral droplets separated by liquid films. This structure is very similar to the gas-liquid foam structure, which is why it is called biliquid foam. The gel emulsion is different from the common emulsion, and the liquid drops in the system have no fluidity; from the appearance, the gel emulsion and the common gel are not different, but the internal structures of the gel emulsion and the common gel are completely different, the dispersed phase and the continuous phase are two phases with completely different properties, generally, water is one phase, and an organic solvent which is not soluble in water is the other phase. Gel emulsions can be classified into water-in-oil (W/O), oil-in-water (O/W), and supercritical CO-in-water (CO-W) depending on the polarity of the dispersed phase and the continuous phase₂Oil-in-oil (O/O), and multiple emulsions (W/O/W or O/W/O). Gel emulsions have important roles in the cosmetics, pharmaceutical, food and petroleum industries.

The stabilizer is critical to the formation and stabilization of the gel emulsion. At present, there are three main types of stabilizers for preparing gel emulsions: surfactant, solid micro-nano particles and small molecule gelling agent. The surfactant is the most common stabilizer at the earliest time, but the dosage of the surfactant as the stabilizer is large and needs to reach 5-30% of that of a continuous phase; the gel emulsion using solid micro-nano particles as a stabilizer is easy to generate phase inversion. The small molecular gelling agent is used as a stabilizing agent to gel the continuous phase and physically wrap the dispersed phase to form a gel emulsion. The three stabilizers mentioned above are all compounds with determined structures, but a method for preparing gel emulsion by using a compound generated by in-situ reaction of two raw materials in an oil-water system as a stabilizer is not seen yet.

One of the most important applications of gel emulsions is the preparation of low density porous materials using them as templates. If the continuous phase of the gel emulsion is polymerizable monomer, various types of porous materials can be obtained after the initiation polymerization of the continuous phase and the volatilization of the dispersed phase.

Disclosure of Invention

The invention aims to provide a preparation method of gel emulsion and a low-density porous metal complex material prepared by using the gel emulsion as a template. The preparation method breaks through the preparation idea of common gel emulsion and has very obvious characteristics and advantages. In addition, the low-density porous metal complex material prepared by using the gel emulsion as a template has the characteristics of simple preparation, excellent performance, large-scale production, convenient processing and the like, does not need large-scale professional equipment in the preparation process, and is easy to realize large-scale industrial production.

Aiming at the purposes, the preparation method of the gel emulsion comprises the following steps: dissolving an organic ligand into an organic solvent immiscible with water at 50-80 ℃, dissolving terbium nitrate or europium nitrate into distilled water, and mixing and stirring the two solutions to form a gel emulsion; in the gel emulsion, the mass ratio of terbium nitrate or europium nitrate to the organic ligand to the water-immiscible organic solvent is 1: 2-5: 90-400, and the distilled water accounts for 50-95% of the total mass of the distilled water and the organic solvent.

The structural formula of the organic ligand is shown as follows:

wherein n is 4, 6, 8 or 10. The synthesis method comprises the following steps:

1. adding cholesterol and potassium hydroxide into tetrahydrofuran at room temperature, and refluxing for 1 hour; then adding dibromoalkane, wherein the molar ratio of cholesterol to potassium hydroxide to dibromoalkane is 1: 3-6, and continuously refluxing for 15 hours; evaporating tetrahydrofuran under reduced pressure, washing with water to neutrality, washing with methanol to remove dibromoalkane, and separating with mixed liquid of petroleum ether and dichloromethane at volume ratio of 1: 1 as mobile phase and silica gel as fixed phase column chromatography to obtain compound of formula I, wherein the reaction equation is as follows:

2. adding anhydrous potassium carbonate and 5-dimethyl hydroxyisophthalate into DMF, introducing nitrogen at room temperature for 30 minutes, heating to 65 ℃, adding a compound shown in the formula I, heating to 80 ℃, reacting for 9 hours, adding ice water for suction filtration, and performing chromatographic separation by using a mixed solution of petroleum ether and dichloromethane in a volume ratio of 1: 1 as a mobile phase and silica gel as a fixed phase column to obtain a compound shown in the formula II, wherein the reaction equation is as follows:

3. dissolving a compound shown in a formula II in absolute ethyl alcohol, adding 1-3 mol/L sodium hydroxide aqueous solution, refluxing for 12 hours, adjusting the pH value to 1 by using 1-3 mol/L hydrochloric acid, and performing suction filtration to obtain an organic ligand shown in a formula III, wherein the reaction equation is as follows:

in the preparation method of the gel emulsion, the mass ratio of terbium nitrate or europium nitrate, the organic ligand and the water-immiscible organic solvent in the gel emulsion is preferably 1: 3.5-4.5: 100-300, and the distilled water accounts for 70-85% of the total mass of the distilled water and the organic solvent.

In the preparation method of the gel emulsion, the organic ligand is preferably dissolved in an organic solvent immiscible with water at 65-75 ℃.

In the preparation method of the gel emulsion, the organic solvent immiscible with water is any one of benzene, toluene, p-xylene and styrene.

In the preparation process of the gel emulsion, when the organic solvent immiscible with water is styrene, dissolving an organic ligand, an initiator and a cross-linking agent into the styrene at 50-80 ℃, dissolving terbium nitrate or europium nitrate into distilled water, mixing and stirring the two solutions to form a gel emulsion containing the initiator and the cross-linking agent, polymerizing the gel emulsion at 50-80 ℃ for 20-24 hours, and drying at room temperature to prepare the low-density fluorescent porous metal complex material; wherein the mass ratio of terbium nitrate or europium nitrate, the organic ligand, the initiator, the cross-linking agent and the styrene is 1: 2-5: 10-20: 20-50: 90-400, and the distilled water accounts for 50-95% of the total mass of the distilled water and the styrene; preferably, the mass ratio of terbium nitrate or europium nitrate, the organic ligand, the initiator, the cross-linking agent and the styrene is 1: 3.5-4.5: 10-15: 30-40: 100-300, and the distilled water accounts for 70-85% of the total mass of the distilled water and the styrene.

In the preparation process of the gel emulsion, preferably, an organic ligand, an initiator and a cross-linking agent are dissolved in styrene at 50-80 ℃, terbium nitrate or europium nitrate is dissolved in distilled water, the two solutions are mixed and stirred to form the gel emulsion containing the initiator and the cross-linking agent, the gel emulsion is polymerized for 24 hours at 65-70 ℃, and the gel emulsion is dried at room temperature to prepare the low-density fluorescent porous metal complex material.

The initiator is azobisisobutyronitrile, and the crosslinking agent is divinylbenzene.

The invention provides a brand new method for preparing gel emulsion, which comprises the steps of dissolving synthesized organic ligand in oil phase to form solution, mixing the solution with metal salt in water phase, and using the complex formed by the in-situ self-assembly reaction of the organic ligand and metal ions at the oil-water interface as a stabilizer to obtain W/O type gel emulsion with reversible destroying-recovering thixotropic property. When the oil phase is a polymerizable monomer, the gel emulsion can be used as a template, a low-density porous metal complex material is prepared by initiating polymerization of the oil phase, and the porous material can be dried at room temperature without supercritical drying, freeze drying and other high-energy-consumption means.

Drawings

FIG. 1 is an optical micrograph of a gel emulsion prepared in example 1.

FIG. 2 is a scanning electron micrograph of the gel emulsion prepared in example 1 after freeze-drying.

FIG. 3 is a graph of the rheological linear range of the gel emulsion prepared in example 1.

Fig. 4 is a rheological test chart of 10 cycles of destruction-recovery of the gel emulsion prepared in example 1.

FIG. 5 is an optical micrograph of a gel emulsion prepared in example 5.

FIG. 6 is a scanning electron micrograph of the low density porous terbium complex material prepared in example 6.

FIG. 7 is a photograph of a low density porous terbium complex material prepared in example 6.

FIG. 8 is a scanning electron micrograph of a low density porous europium complex material prepared in example 7.

Detailed Description

The present invention will be described in further detail with reference to the following drawings and examples, but the present invention is not limited to these examples.

The preparation of the organic ligands used in the following examples consisted of the following steps:

1. 6g (15.6mmol) of cholesterol and 4.4g (78mmol) of potassium hydroxide are added to 50mL of tetrahydrofuran at room temperature and refluxed for 1 hour; then 11.92mL (78mmol) of 1, 6-dibromohexane is added, and the reflux is continued for 15 hours; evaporating tetrahydrofuran under reduced pressure, washing with water to neutrality, washing with methanol to remove 1, 6-dibromohexane, and separating with mixed liquid of petroleum ether and dichloromethane at volume ratio of 1: 1 as mobile phase and silica gel as fixed phase column chromatography to obtain compound of formula I-1, wherein the reaction equation is as follows:

2. adding 1.78g (12.88mmol) of anhydrous potassium carbonate and 2.70g (12.88mmol) of 5-hydroxyisophthalic acid dimethyl ester into 20mL of DMF, introducing nitrogen for 30 minutes at room temperature, heating to 65 ℃, adding 3.54g (6.44mmol) of a compound shown as a formula I-1, heating to 80 ℃, reacting for 9 hours, adding ice water to 300mL, performing suction filtration, and performing column chromatography by using a mixed solution of petroleum ether and dichloromethane in a volume ratio of 1: 1 as a mobile phase and silica gel as a fixed phase to obtain a compound shown as a formula II-1, wherein the reaction equation is as follows:

3. 2.4g (3.5mmol) of the compound of formula II-1 is added to 40mL of absolute ethanol, stirred and dissolved, then 20mL of 1.75mol/L aqueous sodium hydroxide solution is added, refluxed for 12 hours, adjusted to pH 1 with 1.5mol/L hydrochloric acid, and filtered by suction to obtain the organic ligand shown in formula III-1, and the reaction equation is as follows:

the structural characterization data of the organic ligand represented by formula III-1 are:¹H NMR:(DMSO-d_6/Me₄si,400Hz) < delta (ppm): 13.24(s,2H, COOH),8.06(s,1H, phenyl ring), 7.62(s,2H, phenyl ring), 5.28(s,1H, cholesterol), 4.05(t,2H, OCH)₂),3.40(t,2H,OCH₂) 3.03(m,1H, oxyclohexyl), 2.36-0.68 (m,51H, cholesterol and CH)₂)；HRMS(ESI,m/z)C₄₁H₆₂O₆，649.4484[(M-H)+]。

Example 1

3.9g of the organic ligand shown as the formula III-1 is dissolved into 172g of p-xylene at 65 ℃, 1g of terbium nitrate pentahydrate is dissolved into 800g of distilled water, wherein the mass ratio of the terbium nitrate pentahydrate, the organic ligand and the p-xylene is 1: 3.9: 172, the amount of the distilled water is 82% of the total mass of the distilled water and the p-xylene, and the two solutions are mixed and stirred to form gel emulsion.

The prepared gel emulsion is characterized by an ISH500 optical microscope and an AR-G2 rheometer, and the dried gel emulsion is characterized by an S-3400N II type environment scanning electron microscope, and the result is shown in a figure 1-4. As can be seen from fig. 1, the prepared gel emulsion exhibited a microstructure typical of the gel emulsion, and the dispersed droplets were pressed against each other to cause irregularities in the shape thereof; FIG. 2 is a scanning electron micrograph of the prepared gel emulsion after freeze-drying showing a lamellar microstructure; the prepared gel emulsion has good rheological property, the linear range test result of the gel emulsion is shown in figure 3, the test frequency is 1Hz, the temperature is 20 ℃, and as can be seen from the figure, the storage modulus G' of the gel emulsion is 3000Pa, the yield stress is 57Pa, and the solid characteristic is shown; FIG. 4 shows the results of multiple destruction-recovery cycles performed on the gel emulsion samples at a frequency of 1Hz and at a temperature of 20 deg.C, and it can be seen that the gel emulsion has good shear thixotropic properties and can undergo at least ten destruction-recovery cycles.

Example 2

3.9g of the organic ligand shown as the formula III-1 is dissolved into 175g of benzene at 65 ℃, 1g of europium nitrate hexahydrate is dissolved into 800g of distilled water, wherein the mass ratio of the europium nitrate hexahydrate, the organic ligand and the benzene is 1: 3.9: 175, the amount of the distilled water is 82 percent of the total mass of the distilled water and the benzene, and the two solutions are mixed and stirred until a gel emulsion is formed.

Example 3

3.9g of the organic ligand shown as the formula III-1 is dissolved into 175g of toluene at 65 ℃, 1g of terbium nitrate pentahydrate is dissolved into 800g of distilled water, wherein the mass ratio of the terbium nitrate pentahydrate to the organic ligand to the toluene is 1: 3.9: 173, the amount of the distilled water is 82 percent of the total mass of the distilled water and the toluene, and the two solutions are mixed and stirred to form a gel emulsion.

Example 4

In this example, europium nitrate hexahydrate in example 2 was replaced with terbium nitrate pentahydrate in an equal mass, and the other steps were the same as in example 2 to obtain a gel emulsion.

Example 5

3.9g of the organic ligand shown as the formula III-1 is dissolved into 172g of p-xylene at 65 ℃, 1g of terbium nitrate pentahydrate is dissolved into 600g of distilled water, wherein the mass ratio of the terbium nitrate pentahydrate, the organic ligand and the p-xylene is 1: 3.9: 172, the amount of the distilled water is 78% of the total mass of the distilled water and the p-xylene, and the two solutions are mixed and stirred to form gel emulsion.

The prepared gel emulsion was characterized by ISH500 optical microscope and the results are shown in fig. 5. As can be seen from fig. 5, the prepared gel emulsion exhibited a typical emulsion structure, and the droplets exhibited a spherical shape, and as compared with fig. 1, when the water content as the dispersed phase was changed from low to high, the droplets gradually changed from a spherical shape to an irregular shape, and the wall thickness of the droplets also gradually decreased.

Example 6

3.9g of the organic ligand shown in the formula III-1, 11g of azobisisobutyronitrile and 36g of divinylbenzene are dissolved into 180g of styrene at 65 ℃, 1g of terbium nitrate pentahydrate is dissolved into 800g of distilled water, wherein the mass ratio of the terbium nitrate pentahydrate to the organic ligand to the azobisisobutyronitrile to the divinylbenzene to the styrene is 1: 3.9: 11: 36: 180, and the amount of the distilled water is 82 percent of the total mass of the distilled water and the styrene, and the two solutions are mixed and stirred to form a gel emulsion. Polymerizing the gel emulsion for 24 hours at 70 ℃, and drying at room temperature to prepare the low-density fluorescent porous terbium complex material.

The prepared low-density fluorescent porous terbium complex material is characterized by an S-3400N II type environment scanning electron microscope, the result is shown in figure 6, and the picture of the material under sunlight and an ultraviolet lamp is shown in figure 7. As can be seen from FIG. 6, the material shows a distinct porous structure, the size of the pores is about 60 μm, and the density of the material is 0.222g/cm³(ii) a It can be seen from FIG. 7 that this material has green fluorescence.

Example 7

In the embodiment, equal mass of europium nitrate hexahydrate is used for replacing terbium nitrate pentahydrate in the embodiment 6, and other steps are the same as the embodiment 6, so that the low-density fluorescent porous europium complex material is prepared.

The prepared low-density fluorescent porous europium complex material is characterized by an S-3400N II type environment scanning electron microscope, and the result is shown in figure 8. As can be seen from FIG. 8, the material shows a remarkable porous structure, and the size of the pores is between 40 and 80 microns.

Example 8

3.9g of the organic ligand represented by the formula III-1, 11g of azobisisobutyronitrile and 36g of divinylbenzene were dissolved in 180g of styrene at 65 ℃, 1g of europium nitrate hexahydrate was dissolved in 600g of distilled water, wherein the mass ratio of europium nitrate hexahydrate, organic ligand, azobisisobutyronitrile, divinylbenzene and styrene was 1: 3.9: 11: 36: 180, and the amount of distilled water was 77% of the total mass of distilled water and styrene, and the two solutions were mixed and stirred to form a gel emulsion. Polymerizing the gel emulsion for 24 hours at 70 ℃, and drying at room temperature to prepare the low-density fluorescent porous europium complex material.