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 . The adsorption material of  claim 1 , wherein the metal-organic framework is a framework selected from the group of frameworks consisting essentially of M-BTT where (M=Ca, Fe, Mn, Cu, Co, Ni, Cr, Cd) and (BTT=1,3,5-benzenetristetrazolate) and M-BTTri where (M=Cr, Mn, Fe, Co, Ni, Cu) and (BTTri=1,3,5-benzenetristriazolate). 
     
     
         3 . The adsorption material of  claim 1 , wherein the metal-organic framework is a framework selected from the group of frameworks consisting essentially of M-BTP where (M=Co, Ni, Zn) (BTP=1,3,5-benzenetrispyrazolate) and M 3 (BTC) 2  where (M=Cu, Cr) and (BTC=1,3,5-benzenetriscarboxylate). 
     
     
         4 . The adsorption material of  claim 1 , wherein the metal-organic framework is a framework selected from the group of frameworks consisting essentially of MIL-100 where (M=Fe, Al, Cr, Ti, Sc, V) and Ligand=BTC=1,3,5-benzenetriscarboxylate) and MIL-101 (M=Fe, Al, Cr, Ti, Sc, V) and (Ligand=BDC=1,4-benzenedicarboxylate. 
     
     
         5 . The adsorption material of  claim 1 , wherein the metal-organic framework comprises M 2 (dobdc) (M=Mg, Ca, Mn, Cr, Fe, Co, Ni, Cu, Zn) (dobdc=2,5-dioxido-1,4-benzenedicarboxylate). 
     
     
         6 . The adsorption material of  claim 1 , wherein the basic nitrogen group is incorporated into the framework on a ligand prior to framework formation. 
     
     
         7 . The adsorption material of  claim 1 , wherein the basic nitrogen group is incorporated into the framework through substitution or modification of a functional group that was bonded to a ligand prior to framework formation. 
     
     
         8 . The adsorption material of  claim 1 , wherein the basic nitrogen group is incorporated into the framework by substitution of a ligand after framework formation with the ligand with a basic nitrogen group. 
     
     
         9 . The adsorption material of  claim 1 , wherein the ligand comprises a first functional group reactive to metal atoms in the metal-organic framework and a second functional group reactive with carbon dioxide. 
     
     
         10 . The adsorption material of  claim 9 , wherein the first functional group of the ligand comprises a phenyl group. 
     
     
         11 . The adsorption material of  claim 9 , wherein the first functional group of the ligand comprises a carboxylate group, a triazolate group, a pyrazolate, a tetrazolates, a pyridine, or a sulfate. 
     
     
         12 . The adsorption material of  claim 1 , wherein the ligand comprises a primary alkylamine, a secondary alkylamine, a tertiary alkylamine, a primary imine, or a secondary imine. 
     
     
         13 . The adsorption material of  claim 1 , wherein the metal-organic framework comprises open metal sites and ligand occupied metal sites. 
     
     
         14 . The adsorption material of  claim 1 , wherein the adsorption material has an isosteric heat of CO 2  adsorption of greater than −60 kJ/mol at zero coverage using a dual-site Langmuir model. 
     
     
         15 . 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.   
     
     
         16 . The method as recited in  claim 15 , wherein the metal-organic framework is a framework selected from the group of frameworks consisting essentially of M-BTT where (M=Ca, Fe, Mn, Cu, Co, Ni, Cr, Cd) and (BTT=1,3,5-benzenetristetrazolate); M-BTTri where (M=Cr, Mn, Fe, Co, Ni, Cu) and (BTTri=1,3,5-benzenetristriazolate); M-BTP where (M=Co, Ni, Zn) (BTP=1,3,5-benzenetrispyrazolate); M 3 (BTC) 2  where (M=Cu, Cr) and (BTC=1,3,5-benzenetriscarboxylate); MIL-100 where (M=Fe, Al, Cr, Ti, Sc, V) and Ligand=BTC=1,3,5-benzenetriscarboxylate); MIL-101 (M=Fe, Al, Cr, Ti, Sc, V) and (Ligand=BDC=1,4-benzenedicarboxylate, and M 2 (dobdc) (M=Mg, Ca, Mn, Cr, Fe, Co, Ni, Cu, Zn) (dobdc=2,5-dioxido-1,4-benzenedicarboxylate). 
     
     
         17 . The method as recited in  claim 15 , wherein the ligand is selected from the group of ligands consisting essentially of a carboxylate group, a triazolate group, a pyrazolate, a tetrazolates, a pyridine, or a sulfate. 
     
     
         18 . The method as recited in  claim 15 , wherein the ligand comprises a primary alkylamine, a secondary alkylamine, a tertiary alkylamine, a primary imine, or a secondary imine. 
     
     
         19 . 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.   
     
     
         20 . The method as recited in  claim 19 , wherein the metal-organic framework and plurality of ligands comprises mmen-CuBTTri.