Alkylamine functionalized metal-organic frameworks for composite gas separations

Abstract

Functionalized metal-organic framework adsorbents with ligands containing basic nitrogen groups such as alkylamines and alkyldiamines appended to the metal centers and method of isolating carbon dioxide from a stream of combined gases and carbon dioxide partial pressures below approximately 1 and 1000 mbar. The adsorption material has an isosteric heat of carbon dioxide adsorption of greater than −60 kJ / mol at zero coverage using a dual-site Langmuir model.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a 35 U.S.C. §111(a) continuation of PCT international application number PCT / US2012 / 060915 filed on Oct. 18, 2012, incorporated herein by reference in its entirety, which claims the benefit of U.S. provisional patent application Ser. No. 61 / 548,676 filed on Oct. 18, 2011, incorporated herein by reference in its entirety. Priority is claimed to each of the foregoing applications.

[0002] The above-referenced PCT international application was published as PCT International Publication No. WO 2013 / 059527 on Apr. 25, 2013, incorporated herein by reference in its entirety.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0003] This invention was made with Government support under DE-SC0001015 awarded by the Department of Energy. The Government has certain rights in the invention.INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED IN A COMPUTER PROGRAM APPENDIX

[0004] Not ApplicableBACKGROUND OF THE INVENTION

[0005] 1. Fi...

Examples

example 1

[0070]In order to demonstrate the functionality of metal-organic frameworks featuring coordinatively-unsaturated metal centers for separating gases, a mmen-CuBTTri framework as shown in FIG. 1 was constructed and tested.

[0071]A sample of CuBTTri (100.0 mg, 32.4 / μmol) was suspended in 10 mL of anhydrous hexane under nitrogen, and 75.4 μL (61.2 μg, 701 μmol, 1.8 equivalents per unsaturated CUII site) of N,N′ dimethylethylenediamine (mmen) was added via micropipette with stirring. The compound immediately turned blue and the suspension was heated at reflux for 18 hours under nitrogen. The solid was collected by filtration and washed with successive aliquots of hexane (5×10 mL) to remove unreacted diamine. The solid was then dried under reduced pressure to remove hexane. Anal. Calcd. for C144H195Cl3Cu12N96 (Mw=4139.6 g / mol): C, 41.78; H, 4.75; N, 32.48. Found: C, 42.23; H, 4.47; N, 32.05.

[0072]The grafted material, mmen-CuBTTri, was then activated by heating at 50° C. for 24 hours under...

example 2

[0074]In order to demonstrate the functionality of metal-organic frameworks featuring coordinatively-unsaturated metal centers for separating gases, a mmen-CuBTTri framework as shown in FIG. 1 was constructed and tested.

[0075]The mmen-CuBTTri and men-CuBTTri adsorbents were initially tested in the context of separating a mixture stream including CO2 and N2 to obtain a stream richer in N2 as compared to the mixture stream, with the adsorption of CO2 in the frameworks at low pressures.

[0076]Gas adsorption isotherms for pressures in the range 0-1.1 bar were measured by a volumetric method using a Micromeritics ASAP2020 instrument. A sample was transferred in an N2 filled glovebag to a pre-weighed analysis tube, which was capped with a transeal and evacuated by heating (50° C. for mmen-CuBTTri, 100° C. for men-CuBTTri) under dynamic vacuum for 24 hours. The evacuated analysis tube containing the degassed sample was then carefully transferred to an electronic balance and weighed again to...

example 3

[0088]To further characterize the mmen-CuBTTri frameworks, the isosteric heat of adsorption and working capacity of the materials were analyzed. Utilizing a dual-site Langmuir adsorption model, isosteric heats of adsorption were calculated for CO2 in mmen-CuBTTri and compared to those obtained from data for bare CuBTTri, which were fit using a single-site Langmuir model to give a value of −24 kJ / mol. The N2 adsorption isotherm for mmen-CuBTTri was also fit to a single-site Langmuir model, resulting in a calculated isosteric heat of adsorption of −15 kJ / mol.

[0089]The isosteric heat of CO2 adsorption in mmen-CuBTTri approaches −96 kJ / mol at zero coverage, corresponding to the largest value yet reported for CO2 adsorption in a metal-organic framework. For comparison to mmen-CuBTTri, the heat of adsorption for en-CuBTTri was recalculated with the same dual-site Langmuir model. Because this model incorporates absolute adsorption, direct comparisons between the two different models are no...

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a 35 U.S.C. §111(a) continuation of PCT international application number PCT / US2012 / 060915 filed on Oct. 18, 2012, incorporated herein by reference in its entirety, which claims the benefit of U.S. provisional patent application Ser. No. 61 / 548,676 filed on Oct. 18, 2011, incorporated herein by reference in its entirety. Priority is claimed to each of the foregoing applications.

[0002] The above-referenced PCT international application was published as PCT International Publication No. WO 2013 / 059527 on Apr. 25, 2013, incorporated herein by reference in its entirety.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0003] This invention was made with Government support under DE-SC0001015 awarded by the Department of Energy. The Government has certain rights in the invention.INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED IN A COMPUTER PROGRAM APPENDIX

[0004] Not ApplicableBACKGROUND OF THE INVENTION

[0005] 1. Fi...

Examples

example 1

[0070]In order to demonstrate the functionality of metal-organic frameworks featuring coordinatively-unsaturated metal centers for separating gases, a mmen-CuBTTri framework as shown in FIG. 1 was constructed and tested.

[0071]A sample of CuBTTri (100.0 mg, 32.4 / μmol) was suspended in 10 mL of anhydrous hexane under nitrogen, and 75.4 μL (61.2 μg, 701 μmol, 1.8 equivalents per unsaturated CUII site) of N,N′ dimethylethylenediamine (mmen) was added via micropipette with stirring. The compound immediately turned blue and the suspension was heated at reflux for 18 hours under nitrogen. The solid was collected by filtration and washed with successive aliquots of hexane (5×10 mL) to remove unreacted diamine. The solid was then dried under reduced pressure to remove hexane. Anal. Calcd. for C144H195Cl3Cu12N96 (Mw=4139.6 g / mol): C, 41.78; H, 4.75; N, 32.48. Found: C, 42.23; H, 4.47; N, 32.05.

[0072]The grafted material, mmen-CuBTTri, was then activated by heating at 50° C. for 24 hours under...

example 2

[0074]In order to demonstrate the functionality of metal-organic frameworks featuring coordinatively-unsaturated metal centers for separating gases, a mmen-CuBTTri framework as shown in FIG. 1 was constructed and tested.

[0075]The mmen-CuBTTri and men-CuBTTri adsorbents were initially tested in the context of separating a mixture stream including CO2 and N2 to obtain a stream richer in N2 as compared to the mixture stream, with the adsorption of CO2 in the frameworks at low pressures.

[0076]Gas adsorption isotherms for pressures in the range 0-1.1 bar were measured by a volumetric method using a Micromeritics ASAP2020 instrument. A sample was transferred in an N2 filled glovebag to a pre-weighed analysis tube, which was capped with a transeal and evacuated by heating (50° C. for mmen-CuBTTri, 100° C. for men-CuBTTri) under dynamic vacuum for 24 hours. The evacuated analysis tube containing the degassed sample was then carefully transferred to an electronic balance and weighed again to...

example 3

[0088]To further characterize the mmen-CuBTTri frameworks, the isosteric heat of adsorption and working capacity of the materials were analyzed. Utilizing a dual-site Langmuir adsorption model, isosteric heats of adsorption were calculated for CO2 in mmen-CuBTTri and compared to those obtained from data for bare CuBTTri, which were fit using a single-site Langmuir model to give a value of −24 kJ / mol. The N2 adsorption isotherm for mmen-CuBTTri was also fit to a single-site Langmuir model, resulting in a calculated isosteric heat of adsorption of −15 kJ / mol.

[0089]The isosteric heat of CO2 adsorption in mmen-CuBTTri approaches −96 kJ / mol at zero coverage, corresponding to the largest value yet reported for CO2 adsorption in a metal-organic framework. For comparison to mmen-CuBTTri, the heat of adsorption for en-CuBTTri was recalculated with the same dual-site Langmuir model. Because this model incorporates absolute adsorption, direct comparisons between the two different models are no...

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