Application of metal organic phosphonic acid compound with controllable pore size in SO2 gas adsorption

Abstract

The invention discloses an application of a pore-size-controllable metal organic phosphonic acid compound in SO2 gas adsorption, which comprises the following steps: taking the pore-size-controllable metal organic phosphonic acid compound, firstly carrying out supercritical treatment with carbon dioxide, then placing in an adsorption instrument for activating treatment, and finally carrying out SO2 gas adsorption. The metal phosphonic acid compound with the controllable pore size has relatively high adsorption capacity on SO2 gas; the preparation conditions of the metal phosphonic acid compound with the controllable pore size are mild, the operation is easy, and the preparation process is simple; the preparation yield of the metal phosphonic acid compound with the controllable pore size is high, raw material conversion reaches 95%, and the problems that in the prior art, raw materials for preparing compound materials are high in price, and the compound preparation process is complex are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic-inorganic hybrid material applications, and in particular relates to the application of a metal organic phosphonic acid compound with controllable pore size in SO2 gas adsorption. Background Art

[0002] Metal-organic frameworks (MOFs) are porous materials formed by the self-assembly of metal ions or clusters and organic ligands through coordination bonds. They have high specific surface area, adjustable pore size, and functionalized surfaces, which make them promising for gas adsorption and separation. Existing materials used for SO2 adsorption and separation are mostly ZIFs, MILs, or HKUSTs. The commonly used preparation methods and structural characteristics of materials used for sulfur dioxide adsorption are as follows: ZIF-8: It has a zeolite-like structure and high thermal stability, but its original adsorption capacity is low and requires functional modification.

[0003] Zirconium-based carboxylic acid MOF: A unique pyrene-based tripod-shaped organic ligand containing a basic tertiary amine moiety was designed in the literature (J. Am. Chem. Soc., 2023, DOI: 10.1021 / jacs.3c09648). 4+ A highly porous three-dimensional Zr-MOF framework (Zr-TPA) was successfully prepared by coordination assembly under the conditions of a single acid modulator. However, some of the raw materials required for its preparation are expensive, some are highly toxic, and environmentally unfriendly. The process of compound preparation is complex, the preparation conditions are harsh, the yield is relatively low, and there is serious waste of raw materials.

[0004] As organic-inorganic hybrid materials, metal organophosphonates have seen rapid development in the fields of adsorption, ion exchange, sensors, and nonlinear optics due to their excellent thermal and chemical stability. By rationally designing the skeleton structure of the organophosphonate ligand and applying the principles of crystal engineering, metal organophosphonate materials with unique structures can be assembled. Porous metal organophosphonates have been a research hotspot, and their pore size can be manipulated for the adsorption and separation of specific gases. Starting with the 4-carboxylic acid-1-naphthylphosphonic acid ligand, self-assembling it with a metal cobalt salt and adding appropriate auxiliary ligands as structural regulators has yielded metal organophosphonates with controllable pores for SO₂ gas adsorption. However, the application of metal organophosphonates with controllable pore size for SO₂ gas adsorption and separation has not yet been reported. Summary of the Invention

[0005] In view of the problems raised in the background art, the present invention has studied and designed an application of a metal-organic phosphonic acid compound with controllable pore size in the adsorption of SO2 gas, aiming to: provide an application of a metal-organic phosphonic acid compound with high SO2 gas adsorption capacity and controllable pore size in the adsorption of SO2 gas.

[0006] Technical solution of the present invention: An application of a metal-organic phosphonic acid compound with controllable pore size in the adsorption of SO2 gas, comprising the following steps: taking a metal-organic phosphonic acid compound with controllable pore size, first performing supercritical treatment with carbon dioxide, then placing it in an adsorption instrument for activation treatment, and finally performing the adsorption of SO2 gas.

[0007] Preferably, the metal-organic phosphonic acid compound with controllable pore size is obtained by the following preparation method: Dissolve CoCl2·6H2O, organic phosphonic acid ligand 4-carboxy-1-naphthylphosphonic acid (4-cnappH3) and auxiliary ligand in deionized water according to a certain molar ratio, stir for several hours, adjust to a suitable pH value with 0.5 mol / L NaOH solution, then transfer the solution to a reaction kettle with a polytetrafluoroethylene lining, react in an oven at a certain temperature for several hours, and then cool to room temperature to obtain a rose-red to purple-red massive crystal product.

[0008] Preferably, the auxiliary ligand is one of 4,4-bipyridine (4,4-bpy), 1,4-divinylpyridine (1,4-dpe), 1,4-diphenylpyridine (1,4-dpb).

[0009] Preferably, the molar ratio of CoCl2·6H2O, organic phosphonic acid ligand 4-carboxy-1-naphthylphosphonic acid (4-cnappH3) and auxiliary ligand is 1:1:1~5:1:1, and the deionized water is 10 mL.

[0010] Preferably, the stirring time is 1~5 hours.

[0011] Preferably, the pH value is 3.0~4.5.

[0012] Preferably, the oven temperature is 100~140 °C, and the reaction time in the oven is 24~48 hours.

[0013] The innovation points of the present invention are: 1. For the first time, cobalt organic phosphonic acid compounds with different pore sizes are applied to the adsorption of SO2 gas; 2. For the first time, the structures of cobalt organic phosphonic acid compounds with different pore sizes are obtained; 3. Use nitrogen-containing rigid ligands with different lengths as pore size regulators in phosphonic acid compounds.

[0014] Advantages of the present invention: The metal phosphonic acid compound with controllable pore size in the present invention has a high adsorption capacity for SO2 gas; moreover, the preparation conditions of the metal phosphonic acid compound with controllable pore size in the present invention are mild, easy to operate, and the preparation process is simple; the preparation yield of the metal phosphonic acid compound with controllable pore size is high, and the raw material conversion reaches 95%, solving the problems in the prior art such as the high price of raw materials for preparing compound materials, the complex compound preparation process, the harsh preparation conditions, the low yield, and the serious waste of raw materials. Description of the Drawings

[0015] Figure 1 It is a crystal photograph of Compound 1 prepared in Example 1 of the present invention; Figure 2 It is a crystal photograph of Compound 2 prepared in Example 2 of the present invention; Figure 3 It is a crystal photograph of Compound 3 prepared in Example 3 of the present invention; Figure 4 From left to right are the molecular structures of the auxiliary ligands 4,4-bipyridine (4,4-bpy), 1,4-divinylpyridine (1,4-dpe), and 1,4-diphenylpyridine (1,4-dpb) in the present invention; Figure 5 It is a crystal structure diagram of Compound 1 prepared in Example 1 of the present invention; Among them: the pore size of Compound 1 is 11.06×7.09 Å; Figure 6 It is a crystal structure diagram of Compound 2 prepared in Example 2 of the present invention; Among them: the pore size of Compound 2 is 11.06×9.42 Å; Figure 7 It is a crystal structure diagram of Compound 3 prepared in Example 3 of the present invention; Among them: the pore size of Compound 3 is 11.06×11.45 Å; Figure 8 It is a powder X-ray diffraction pattern of Compound 1 prepared in Example 1 of the present invention; Figure 9 It is a powder X-ray diffraction pattern of Compound 2 prepared in Example 2 of the present invention; Figure 10 It is a powder X-ray diffraction pattern of Compound 3 prepared in Example 3 of the present invention. Detailed Embodiments

[0016] The present invention will be further described below in conjunction with specific embodiments.

[0017] Example 1 CoCl2·6H2O, the organic phosphonic acid ligand 4-carboxy-1-naphthylphosphonic acid (4-cnappH3), and the auxiliary ligand 4,4'-bipyridine were dissolved in 10 mL of deionized water in a molar ratio of 1:1:1, stirred for 2 hours, and the pH value was adjusted to 3.2 with 0.5 mol / L NaOH solution. Then the solution was transferred to a reaction kettle with a polytetrafluoroethylene lining and reacted in an oven at 120 °C for 48 hours. After cooling to room temperature, a rose-red block crystal product was obtained, denoted as Co2(4-cnapp)(OH)(pyz) (Compound 1).

[0018] Example 2 CoCl2·6H2O, the organic phosphonic acid ligand 4-carboxy-1-naphthylphosphonic acid (4-cnappH3), and the auxiliary ligand 1,4-divinylbenzene were dissolved in 10 mL of deionized water in a molar ratio of 1:1:1, stirred for 2 hours, and the pH value was adjusted to 3.5 with 0.5 mol / L NaOH solution. Then the solution was transferred to a reaction kettle with a polytetrafluoroethylene lining and reacted in an oven at 120 °C for 48 hours. After cooling to room temperature, a brown-red block crystal product was obtained, denoted as Co2(4-cnapp)(OH)(1,2-dpe) (Compound 2).

[0019] Example 3 CoCl2·6H2O, the organic phosphonic acid ligand 4-carboxy-1-naphthylphosphonic acid (4-cnappH3), and the auxiliary ligand 1,4-diphenylbenzene were dissolved in 10 mL of deionized water in a molar ratio of 1:1:1, stirred for 2 hours, and the pH value was adjusted to 3.5 with 0.5 mol / L NaOH solution. Then the solution was transferred to a reaction kettle with a polytetrafluoroethylene lining and reacted in an oven at 120 °C for 48 hours. After cooling to room temperature, a purple-red block crystal product was obtained, denoted as Co2(4-cnapp)(OH)(1,2-dpb) (Compound 3).

[0020] The compounds prepared in Examples 1 to 3 were respectively applied to the adsorption of SO2 gas. The specific adsorption process was as follows: 100 mg of the above-mentioned metal-organic phosphonic acid compound with controllable pore size was taken, first supercritically treated with carbon dioxide, then placed in an adsorption instrument for activation treatment, and finally the adsorption of SO2 gas was carried out at a temperature of 293K.

[0021] The experimental results showed that metal-organic phosphonic acid compounds with different pores all had an adsorption effect on SO2 gas. With different pore sizes, the adsorption amount of SO2 gas was also different. The adsorption amount of SO2 gas (5.4 mmol / g)[[ID=,17]] Figure 5 shown) of Compound 1 with narrow pores was significantly higher than that of Compound 2 ( ﹣1 ) with wide pores and Compound 3 ( Figure 6 shown).Figure 7 ), the gas adsorption amounts (for Compound 2: 4.12 mmol·g ﹣1 , and for Compound 3: 3.07 mmol·g ﹣1 ) are as shown. From the decrease in the SO2 gas adsorption amounts from Compound 1 to Compound 2 and Compound 3, it can be concluded that the reduction of the material pores promotes the multi-site interaction between SO2 and the inner pore surface.

[0022] In the present invention, the metal phosphonic acid compound with controllable pore size has a relatively high adsorption amount for SO2 gas. The preparation conditions of the metal phosphonic acid compound with controllable pore size are mild, easy to operate, the preparation process is simple, the yield is high, and the raw material conversion reaches 95%. It solves the problems in the prior art such as the high price of raw materials for preparing compound materials, the complex compound preparation process, the harsh preparation conditions, the low yield, and the serious waste of raw materials.

[0023] The above embodiments only illustrate the specific implementation modes of the present disclosure, but the implementation modes of the present disclosure are not limited by the above content. Any changes, modifications, substitutions, combinations, and simplifications made without substantially departing from the gist and principle of the inventive concept of the present disclosure shall be equivalent replacement methods and shall be included within the protection scope determined by the claims.

Claims

1. Application of a metal-organic phosphonic acid compound with controllable pore size in SO2 gas adsorption, characterized in that: It includes the following steps: Take a metal-organic phosphonic acid compound with controllable pore size, first perform supercritical treatment with carbon dioxide, then place it in an adsorption instrument for activation treatment, and finally perform the adsorption of SO2 gas.

2. Use of a metal-organic phosphonic acid compound with controllable pore size in the adsorption of SO2 gas as described in claim 1, characterized in that: The metal-organic phosphonic acid compound with controllable pore size is obtained by the following preparation method: Dissolve CoCl2·6H2O, the organic phosphonic acid ligand 4-carboxy-1-naphthylphosphonic acid (4-cnappH3), and the auxiliary ligand in deionized water according to a certain molar ratio, stir for several hours, adjust to a suitable pH value with 0.5 mol / L NaOH solution, then transfer the solution to a reaction kettle with a polytetrafluoroethylene liner, react in an oven at a certain temperature for several hours, and then cool to room temperature to obtain a block crystal product in rose red to purple red.

3. Use of a metal-organic phosphonic acid compound with controllable pore size in the adsorption of SO2 gas as described in claim 2, characterized in that: The auxiliary ligand is one of 4,4-bipyridine (4,4-bpy), 1,4-divinylpyridine (1,4-dpe), and 1,4-diphenylpyridine (1,4-dpb).

4. Use of a metal-organic phosphonic acid compound with controllable pore size in the adsorption of SO2 gas as claimed in claim 2, characterized in that: The molar ratio of CoCl2·6H2O, the organic phosphonic acid ligand 4-carboxy-1-naphthylphosphonic acid (4-cnappH3), and the auxiliary ligand is 1:1:1 to 5:1:1, and the deionized water is 10 mL.

5. Use of a metal-organic phosphonic acid compound with controllable pore size as described in claim 2 in the adsorption of SO2 gas, characterized in that: The stirring time is 1 to 5 hours.

6. The application of a metal-organic phosphonic acid compound with controllable pore size in the adsorption of SO2 gas as described in claim 2, wherein: The pH value is 3.0 to 4.

5.

7. Use of a metal-organic phosphonic acid compound with controllable pore size as described in claim 2 in the adsorption of SO2 gas, characterized in that: The oven temperature is 100 to 140 °C, and the reaction time in the oven is 24 to 48 hours.

Images