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.

We claim: 
     
         1 . An adsorption material, comprising:
 a porous metal-organic framework; and   a plurality of ligands within the pores of the metal-organic framework, each ligand having at least one basic nitrogen group;   wherein the basic nitrogen groups are configured to selectively adsorb CO 2  from a stream of mixed gases at pressures below 3 bar and CO 2  partial pressures between 1 and 1000 mbar.   
     
     
         2 . A method of separating a mixture stream comprising CO 2  and N 2 , the method comprising:
 contacting the mixture stream comprising CO 2  and N 2  with a material comprising a metal-organic framework, and a ligand with a basic nitrogen group;   wherein the material has an isosteric heat of CO 2  adsorption of greater than −60 kJ/mol at zero coverage using a dual-site Langmuir model;   obtaining a stream richer in CO 2  as compared to the mixture stream; and   obtaining a stream richer in N 2  as compared to the mixture stream.   
     
     
         3 . A method of separating a mixture stream comprising CO 2  and other combustion gases, the method comprising:
 contacting the mixture stream comprising CO 2  and N 2  with a material comprising a metal-organic framework and a plurality of ligands that have at least one basic nitrogen group;   obtaining a stream richer in CO 2  as compared to the mixture stream; and   obtaining a stream richer in N 2  as compared to the mixture stream.