# US 11,305,256 B2 · Hybrid zeolitic imidazolate framework and a method of capturing carbon dioxide

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- Number: US 11,305,256 B2
- Document ID: US11305256B2
- Status: Granted
- Kind: B2
- Application number: 16/720,535
- Filed: 2019-12-19
- Published: 2021-06-24
- Granted: 2022-04-19
- Earliest claimed: 2019-12-19
- Assignees: King Fahd University of Petroleum and Minerals
- Applicants: King Fahd University of Petroleum and Minerals
- Inventors: Muhammad Usman; Bassem A. Al-Maythalony
- Web page: https://patentgrep.com/patent/US11305256B2

## CPC

- B01J 20/226: {Coordination polymers, e.g. metal-organic frameworks [MOF], zeolitic imidazolate frameworks [ZIF] (preparation of metal complexes containing carboxylic acid moieties C07C51/418; MOF's per se C07F)}
- B01D 53/02: by adsorption, e.g. preparative gas chromatography {(solid sorbent compositions B01J20/00, preparation of inorganic compounds or elements C01)}
- B01D 53/04: with stationary adsorbents {(B01D53/025 takes precedence)}
- B01J 20/28059: {being less than 100 m2/g}
- B01J 20/28061: {being in the range 100-500 m2/g}
- B01J 20/28064: {being in the range 500-1000 m2/g}
- B01J 20/28071: {being less than 0.5 ml/g}
- B01J 20/3085: {Chemical treatments not covered by groups B01J20/3007 - B01J20/3078}
- C07D 233/64: with substituted hydrocarbon radicals attached to ring carbon atoms, e.g. histidine
- B01D 2253/108: Zeolites
- B01D 2253/202: Polymeric adsorbents
- B01D 2253/204: Metal organic frameworks (MOF's)
- B01D 2253/306: Surface area, e.g. BET-specific surface
- B01D 2253/311: Porosity, e.g. pore volume
- B01D 2257/504: Carbon dioxide
- Y02C 20/40: of CO2
- Y02P 20/151: Reduction of greenhouse gas [GHG] emissions, e.g. CO2
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08)
- Y02C: CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

A hybrid zeolitic imidazolate framework having an isolated purity of at least 95 wt. %, which is a coordination product formed between zinc(II) ions, a linker of formula (I), and a linker of formula (II); wherein each linker of formulae (I) and (II) links together adjacent zinc(II) ions, R1 and R2 are independently a hydrogen, an optionally substituted alkyl, an optionally substituted aryl, a halo, a nitro, or a cyano, and R3 and R4 are independently hydrogen, an optionally substituted alkyl, an optionally substituted aryl, or an optionally substituted arylalkyl. A method of making the hybrid zeolitic imidazolate framework and a method of capturing CO2 from a gas mixture with the hybrid zeolitic imidazolate framework.

## Claims

### Claim 1

A hybrid zeolitic imidazolate framework having an isolated purity of at least 95 wt. %, which is a coordination product formed between:
zinc(II) ions;
a linker of formula (I); and
a linker of formula (II);
or a stereoisomer or tautomer thereof,
wherein:
each linker of formulae (I) and (II) links together adjacent zinc(II) ions,
R1 and R2 are independently a hydrogen, an optionally substituted alkyl, an optionally substituted aryl, a halo, a nitro, or a cyano, and
R3 and R4 are independently hydrogen, an optionally substituted alkyl, an optionally substituted aryl, or an optionally substituted arylalkyl.

### Claim 2 (depends on 1)

The hybrid zeolitic imidazolate framework of claim 1, wherein a relative mol % of the linker of formula (II) is 10 to 75 mol %, based on a total molar amount of the linkers of formulae (I) and (II).

### Claim 3 (depends on 1)

The hybrid zeolitic imidazolate framework of claim 1, wherein, each based on a total molar amount of the linkers of formulae (I) and (II):
a relative mol % of the linker of formula (II) is 10 mol %,
a relative mol % of the linker of formula (II) is 25 mol %,
a relative mol % of the linker of formula (II) is 50 mol %, or
a relative mol % of the linker of formula (II) is 75 mol %.

### Claim 4 (depends on 1)

The hybrid zeolitic imidazolate framework of claim 1, wherein R1 and R2 are each hydrogen.

### Claim 5 (depends on 1)

The hybrid zeolitic imidazolate framework of claim 1, wherein R3 and R4 are each hydrogen.

### Claim 6 (depends on 1)

The hybrid zeolitic imidazolate framework of claim 1, wherein
the linker of formula (I) is
and the linker of formula (II) is

### Claim 7 (depends on 1)

The hybrid zeolitic imidazolate framework of claim 1, which is isoreticular with ZIF-90.

### Claim 8 (depends on 1)

The hybrid zeolitic imidazolate framework of claim 1, which has a BET surface area of 3 to 850 m2/g.

### Claim 9 (depends on 1)

The hybrid zeolitic imidazolate framework of claim 1, which has a micropore volume of 0.05 to 0.25 cm3/g.

### Claim 10 (depends on 1)

The hybrid zeolitic imidazolate framework of claim 1, which has a CO2 uptake capacity of 20 to 95 cm3/g at 273 K and 15 to 47 cm3/g at 298 K, each at 760 Torr.

### Claim 11 (depends on 1)

The hybrid zeolitic imidazolate framework of claim 1, which has an ideal selectivity of CO2/N2 of 25 to 80, and an ideal selectivity of CO2/CH4 of 5 to 65.

### Claim 12 (depends on 1)

A method of making the hybrid zeolitic imidazolate framework of claim 1, the method comprising:
obtaining a parent zeolitic imidazolate framework formed from coordination between zinc(II) ions and the linker of formula (I);
post-synthetically modifying the parent zeolitic imidazolate framework by reacting a portion of a total number of aldehyde groups present in the parent zeolitic imidazolate framework from the linker of formula (I) with an amino alcohol of formula (III)
H2N—CH(R3)—CH(R4)—OH (III)
in an alcoholic solvent to form the hybrid zeolitic imidazolate framework in a reaction mixture; and
isolating the hybrid zeolitic imidazolate framework from the reaction mixture by filtering, washing with an alcohol, and drying at 80 to 120° C.

### Claim 13 (depends on 12)

The method of claim 12, wherein the parent zeolitic imidazolate framework is post-synthetically modified with a molar ratio of the amino alcohol of formula (III) to the parent zeolitic imidazolate framework of 0.2:1 to 1.6:1, which provides a relative mol % of the linker of formula (II) of 10 to 75 mol %, based on a total molar amount of the linkers of formulae (I) and (II).

### Claim 14 (depends on 12)

The method of claim 12, wherein the amino alcohol of formula (III) is ethanolamine and the linker of formula (I) is
and the linker of formula (II) is

### Claim 15 (depends on 1)

A method of capturing CO2 from a gas mixture, the method comprising:
contacting the gas mixture with the hybrid zeolitic imidazolate framework of claim 1 to adsorb at least a portion of the CO2 into the hybrid zeolitic imidazolate framework, thereby forming a loaded hybrid zeolitic imidazolate framework and a gas stream depleted in CO2 compared to the gas mixture.

### Claim 16 (depends on 15)

The method of claim 15, wherein the gas mixture further comprises at least one other gas selected from the group consisting of hydrogen, oxygen, nitrogen, methane, and carbon monoxide.

### Claim 17 (depends on 15)

The method of claim 15, wherein the gas mixture is a pre-combustion gas mixture comprising 15 to 50 vol. % of CO2, based on a total volume of the gas mixture.

### Claim 18 (depends on 15)

The method of claim 15, wherein the gas mixture is a post-combustion gas mixture comprising 5 to 15 vol. % of CO2, based on a total volume of the gas mixture.

### Claim 19 (depends on 15)

The method of claim 15, wherein the gas mixture has a temperature of −5 to 50° C.

### Claim 20 (depends on 15)

The method of claim 15, wherein the gas stream depleted in CO2 contains at least 25% less CO2 by volume compared to a volume of CO2 present in the gas mixture.