Search

CN-117696012-B - Metal organic framework material and preparation method and application thereof

CN117696012BCN 117696012 BCN117696012 BCN 117696012BCN-117696012-B

Abstract

The invention discloses a metal organic framework material, a preparation method and application thereof. The metal organic framework material provided by the invention comprises metal ions and an organic ligand, wherein the organic ligand is selected from compounds shown in a formula I or a formula II. The metal organic framework material has excellent adsorption separation selectivity to paraxylene. The material has the advantages of low cost, easy acquisition of raw materials, simple preparation process, low cost, good regeneration and repeatability, capability of maintaining the original adsorption effect after vacuum or heating regeneration, and wide industrial application prospect.

Inventors

  • BAO ZONGBI
  • LI JIAQI
  • SHENG BIN
  • GUO LIDONG
  • REN QILONG
  • ZHANG ZHIGUO
  • YANG QIWEI

Assignees

  • 浙江大学
  • 浙江大学衢州研究院

Dates

Publication Date
20260508
Application Date
20231127

Claims (15)

  1. 1. The application of a metal organic framework material in separating and mixing C8 aromatic hydrocarbon isomers, wherein the metal organic framework material comprises metal ions and organic ligands, the organic ligands are selected from one or more of benzimidazole-5-carboxylic acid, benzimidazole-4-carboxylic acid, isonicotinic acid, 3-aminoisonicotinic acid and 2-aminoisonicotinic acid, the metal ions are selected from transition metal ions, pore channels of the metal organic framework material are diamond-shaped, and the pore channel size is 4-10 angstroms.
  2. 2. The use according to claim 1, wherein the metal ions are selected from one or more of molybdenum ions, chromium ions, iron ions, cobalt ions, nickel ions, copper ions and manganese ions, and/or the mixed C8 aromatic isomers comprise at least two of para-xylene, ethylbenzene, ortho-xylene and meta-xylene.
  3. 3. The use according to claim 1, wherein the metal organic framework material is in the shape of cubes, rods or pellets and/or the mixed C8 aromatic isomers comprise ethylbenzene, para-xylene, ortho-xylene and meta-xylene.
  4. 4. The use according to any one of claims 1 to 3, wherein the preparation of the metal organic framework material comprises reacting a metal inorganic salt, an organic ligand and optionally a C1-C4 organic acid in a solvent to produce the metal organic framework material.
  5. 5. The method according to claim 4, wherein the metal inorganic salt is selected from one or more of chloride, nitrate, acetate, carbonate, sulfate or perchlorate of a metal ion, and/or The C1-C4 organic acid is selected from formic acid and/or acetic acid, and/or The solvent comprises an organic solvent selected from acetonitrile, methanol, ethanol, acetone, N-dimethylformamide or N, N-dimethylacetamide, and/or water The molar ratio of the metal inorganic salt to the organic ligand is 1 (0.5-10), the molar ratio of the metal inorganic salt to the C1-C4 organic acid is 1 (0.01-10), and/or The temperature of the reaction is 100-220 ℃, and the time of the reaction is 12-112 h.
  6. 6. The use according to claim 5, wherein the volume ratio of the organic solvent to water is 1 (0.5-3), and/or the molar ratio of the metal inorganic salt to the organic ligand is 1 (0.5-3), and the molar ratio of the metal inorganic salt to the C1-C4 organic acid is 1 (0.5-3.5).
  7. 7. The use according to claim 1, wherein the channels of the metal organic framework material are square and/or the mixed C8 aromatic isomer comprises para-xylene, the para-xylene accounting for 5% -95% by volume.
  8. 8. A process for separating para-xylene from mixed C8 aromatic isomers, which comprises subjecting the mixed C8 aromatic isomers to adsorptive separation with an adsorbent comprising a metallo-organic framework material for separating para-xylene, wherein the metallo-organic framework material is a metallo-organic framework material for use according to any one of claims 1 to 7.
  9. 9. The process according to claim 8, wherein the mixed C8 aromatic isomers are gaseous or liquid, comprising para-xylene and one or more C8 aromatic isomers selected from ethylbenzene, ortho-xylene and meta-xylene, and/or the temperature of the adsorptive separation is from-5 ℃ to 300 ℃, and/or the total vapor pressure of the mixed C8 aromatic isomers is from 1kPa to 1000 kPa.
  10. 10. The process of claim 9 wherein the mixed C8 aromatic isomers comprise ethylbenzene, para-xylene, ortho-xylene, and meta-xylene and/or the adsorptive separation is at a temperature of 25 ℃ to 250 ℃.
  11. 11. The method of claim 9, wherein the temperature of the adsorptive separation is from 30 ℃ to 150 ℃.
  12. 12. The method according to any one of claims 8 to 11, wherein the adsorptive separation is performed using a fixed bed, wherein the adsorbent is packed in the fixed bed adsorption column, or the adsorptive separation is performed using a simulated moving bed, wherein the adsorbent is packed in an adsorption zone bed of the simulated moving bed.
  13. 13. The method of claim 12, wherein the adsorptive separation comprises the steps of: (1) Passing mixed C8 aromatic hydrocarbon isomer steam formed by mixed C8 aromatic hydrocarbon isomers and carrier gas through a fixed bed adsorption column, adsorbing strongly adsorbed paraxylene in the mixed C8 aromatic hydrocarbon isomers on the adsorbent, and penetrating the adsorption column by weakly adsorbed other C8 aromatic hydrocarbon isomers in the mixed C8 aromatic hydrocarbon isomers to obtain weakly adsorbed other C8 aromatic hydrocarbon isomers; (2) Desorbing the strongly adsorbed paraxylene from the adsorbent to obtain strongly adsorbed paraxylene; Or the adsorption separation comprises the following steps: And (3) carrying out adsorption separation on the mixed C8 aromatic hydrocarbon isomer liquid through a liquid phase simulated moving bed, so that paraxylene, orthoxylene and/or metaxylene and ethylbenzene are respectively extracted in different beds.
  14. 14. The method of claim 13, wherein the mixed C8 aromatic hydrocarbon isomer vapor is passed through a fixed bed adsorption column at a flow rate of 20-200 mL/min/g adsorbent, 4-32 adsorbent beds of the simulated moving bed, and 1.0-1.5 adsorbent zone beds.
  15. 15. The method of claim 9, wherein the mixed C8 aromatic isomer comprises 5% to 95% by volume para-xylene.

Description

Metal organic framework material and preparation method and application thereof Technical Field The invention relates to the technical field of adsorption materials and energy sources, in particular to a metal organic framework material and a preparation method and application thereof. Background Para-xylene (PX) is mainly used for producing refined terephthalic acid (PTA), and then PTA is used as a raw material to react with ethylene glycol to further produce polyethylene terephthalate (PET), and finally is used for synthesizing materials such as polyester fibers. An industrial source of xylene isomers is the catalytic reforming of naphtha, by which mixed C8 aromatic isomers can be obtained, including mainly para-xylene (PX), meta-xylene (MX), ortho-xylene (OX) and Ethylbenzene (EB). Since the boiling points of xylene isomers are almost the same, conventional separation techniques such as rectification require a theoretical plate number of 300 or more, and consume a great amount of energy. Thus, the separation of PX from highly similar C8 aromatic isomer mixtures is more difficult. Over 75% of the paraxylene in industry is currently produced by Simulated Moving Bed (SMB) technology, which uses FAU zeolite as the adsorbent, operating in the high temperature range 393 to 523K. However, the boiling point, configuration and other physicochemical properties of the C8 isomer are highly similar, and the molecular sieve structure has poor adjustability, so that the adsorption selectivity of the molecular sieve is very low, and the selectivity of paraxylene and other isomers is not more than 5. Metal organic framework Materials (MOFs), also known as coordination polymers, have extremely high specific surface areas and pore volumes, and can obtain porous structures with different pore channel shapes and pore sizes by changing metal ions and ligand species, as well as synthesis conditions. Furthermore, the MOF structure exhibits unique molecular flexibility (including a door opening effect or a respiratory effect and the like), and the characteristics enable the MOF to represent a remarkable technical advantage in the adsorption separation field. However, most metal-organic framework materials have low selectivity and poor stability, and lose high selectivity at the high temperatures necessary for diffusion. It is a very challenging technical challenge to prepare a metal organic framework material with good stability, considerable para-xylene adsorption and high level of adsorption separation selectivity at low cost. Disclosure of Invention In order to overcome the problems in the prior art, the invention provides a novel metal organic framework material and a method for absorbing and separating paraxylene from mixed C8 aromatic hydrocarbon isomers by using the metal organic framework material as an adsorbent. In a first aspect, the present invention provides a metal organic framework material comprising a metal ion and an organic ligand selected from the group consisting of compounds of formula I or formula II, In the formula I, X 1 is N, X 2 is CH, X 3 is O, S or NH, or X 1 is CH, X 2 is N, X 3 is O, S or NH, R 1、R2、R3 and R 4 are independently selected from hydrogen, hydroxyl, halogen, carboxyl, amino, C1-C4 alkyl and at least one of R 1、R2、R3 and R 4 is selected from carboxyl; in the formula II, R 5 is selected from hydrogen, hydroxyl, halogen, carboxyl, amino and C 1-C4 alkyl, and L is selected from single bond or C6-C10 arylene. In some embodiments, in formula I, X 1 is N, X 2 is CH, X 3 is selected from O or NH, R 1、R2、R3 and R 4 are each independently selected from hydrogen, hydroxy, fluoro, chloro, bromo, carboxy, amino, methyl or ethyl, and only one of R 1、R2、R3 and R 4 is selected from carboxy. In some embodiments, in formula I, X 1 is CH, X 2 is N, X 3 is selected from NH, R 1、R2、R3 and R 4 are each independently selected from hydrogen, hydroxy, fluoro, chloro, bromo, carboxy, amino, methyl or ethyl, and only one of R 1、R2、R3 and R 4 is selected from carboxy. In some embodiments, in formula II, R 5 is selected from hydrogen, hydroxy, fluoro, chloro, bromo, carboxy, amino, methyl, or ethyl, and L is selected from a single bond, phenylene, or benzylidene. In some embodiments, the organic ligand is selected from one or more of benzimidazole-5-carboxylic acid, benzimidazole-4-carboxylic acid, benzoxazole-5-carboxylic acid, indazole-5-carboxylic acid, isonicotinic acid, 3-aminoisonicotinic acid, 2-aminoisonicotinic acid, and 4-pyridinebenzoic acid. In some embodiments, the metal ion is selected from one or more of a transition metal ion and an alkaline earth metal ion. In some embodiments, the metal ion is selected from one or more of calcium ion, molybdenum ion, chromium ion, iron ion, cobalt ion, nickel ion, copper ion, magnesium ion, and manganese ion. In some embodiments, the metal ion of the metal organic framework material is cobalt or nickel ion and the organic ligand is benzimidazole-5-carboxylic acid,