Metal–Organic Frameworks for Separations

Kenji Sumida, David L. Rogow, Jarad A. Mason, Thomas M. McDonald, Eric D. Bloch, Zoey R. Herm, Tae-Hyun Bae, Jeffrey R. Long

Carbon Dioxide Capture in Metal–Organic Frameworks

The escalating level of atmospheric carbon dioxide is one of the most pressing environmental concerns of our age. Carbon capture and storage (CCS) from large point sources such as power plants is one option for reducing anthropogenic CO(2) emissions; however, currently the capture alone will increase the energy requirements of a plant by 25-40%. This Review highlights the challenges for capture technologies which have the greatest likelihood of reducing CO(2) emissions to the atmosphere, namely postcombustion (predominantly CO(2)/N(2) separation), precombustion (CO(2)/H(2)) capture, and natural gas sweetening (CO(2)/CH(4)). The key factor which underlies significant advancements lies in improved materials that perform the separations. In this regard, the most recent developments and emerging concepts in CO(2) separations by solvent absorption, chemical and physical adsorption, and membranes, amongst others, will be discussed, with particular attention on progress in the burgeoning field of metal-organic frameworks.

Carbon Dioxide Capture: Prospects for New Materials

2.2. MOFs with Metal Active Sites 4614 2.2.1. Early Studies 4614 2.2.2. Hydrogenation Reactions 4618 2.2.3. Oxidation of Organic Substrates 4620 2.2.4. CO Oxidation to CO2 4626 2.2.5. Phototocatalysis by MOFs 4627 2.2.6. Carbonyl Cyanosilylation 4630 2.2.7. Hydrodesulfurization 4631 2.2.8. Other Reactions 4632 2.3. MOFs with Reactive Functional Groups 4634 2.4. MOFs as Host Matrices or Nanometric Reaction Cavities 4636

Engineering Metal Organic Frameworks for Heterogeneous Catalysis

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Metal–Organic Frameworks and Self-Assembled Supramolecular Coordination Complexes: Comparing and Contrasting the Design, Synthesis, and Functionality of Metal–Organic Materials

Three different porous metal organic framework (MOF) materials have been prepared with and without uncoordinated amine functionalities inside the pores. The materials have been characterized and tested as adsorbents for carbon dioxide. At 298 K the materials adsorb significant amount of carbon dioxide, the amine functionalised adsorbents having the highest CO2 adsorption capacities, the best adsorbing around 14 wt% CO2 at 1.0 atm CO2 pressure. At 25 atm CO2 pressure, up to 60 wt% CO2 can be adsorbed. At high pressures the CO2 uptake is mostly dependent on the available surface area and pore volume of the material in question. For one of the iso-structural MOF pairs the introduction of amine functionality increases the differential adsorption enthalpy (from isosteric method) from 30 to around 50 kJ/mole at low CO2 pressures, while the adsorption enthalpies reach the same level at increase pressures. The high pressure experimental results indicate that MOF based solid adsorbents can have a potential for use in pressure swing adsorption of carbon dioxide at elevated pressures.

Amine functionalised metal organic frameworks (MOFs) as adsorbents for carbon dioxide

The heterobimetallic metal–organic framework {[(BPDC)PtCl2]3(Gd(H2O)3)2}·5H2O (BPDC = 2,2′-bipyridine-5,5′-dicarboxylate) has been designed and synthesized by hydrothermal methods. The new coordination polymer contains subunits of (BPDC)PtCl2 (1) where both N atoms of the BPDC ligand are attached to a square-planar Pt(II) center. The two remaining cis coordination sites at Pt(II) are occupied by chloride ions. The final structure (2) of the polymeric network is obtained when Gd(III) ions link together the (BPDC)PtCl2 units, which are organized in sheets, into larger blocks. These blocks are stacked along the crystallographic [010] direction and are held together by a hydrogen bonding scheme that involves carboxylate oxygen atoms and water molecules in the coordination sphere of Gd. The coordination polymer 2 can be obtained in a single-step reaction or in a two-step synthesis where the corresponding Pt complex (1) was first synthesized followed by reacting 1 with Gd(NO3)3·6H2O. In situ high temperature powder X-ray diffraction shows that the crystalline coordination polymer transforms into an anhydrous modification at 100 °C. This modification is stable to 350 °C, at which temperature the structure starts to decompose. The coordination sphere around platinum in the polymer closely resembles organometallic Pt complexes that have been previously found to catalytically or stoichiometrically activate and functionalize hydrocarbon C–H bonds in homogeneous systems.

Design, synthesis and characterization of a Pt–Gd metal–organic framework containing potentially catalytically active sites

The reaction between Zn(NO3)2·6H2O and 5-aminoisophthalic acid (aip) in a mixture of diethylformamide (DEF) and ethanol resulted in [Zn(C8H5NO4)(C5H11NO)]n (CPO-8-DEF). This compound is composed of infinite 2D layers with tetrahedral Zn atoms and aip ligands in a triangular topology. The DEF molecules are bonded to Zn, and within each layer, the DEF molecules are oriented in the same direction, while in the subsequent layer, the DEF molecules are oriented in the opposite direction. By introduction of the pillaring ligands 4,4-bipyridine (BPY), 1,2-di-4-pyridylethylene (DPE), 1,2-di-4-pyridylethane (DPA), and 1,3-di-4-pyridylpropane (DPP) into mixtures of N,N‘-dimethylformamide and water with Zn(NO3)2 and aip, we have successfully synthesized a series of related pillared bilayer compounds with the same common triangular Zn(aip) layer structural motif as that observed in CPO-8-DEF. The compounds are denoted as CPO-8-BPY ([Zn(C8H5NO4)(C10H8N2)0.5]n·3nH2O), CPO-8-DPE ([Zn(C8H5NO4)(C12H10N2)0.5]n·2.5nH2O), CPO...

Design of novel bilayer compounds of the CPO-8 type containing 1D channels.

Synthesis and characterization of CPO-1; three-dimensional coordination polymers with 2,6-naphthalenedicarboxylate (ndc) ligands [M(ndc)(H2O)], M=Mn(II), Zn(II) or Cd(II)

The principal alternative for long-distance transportation of CO 2 from source to storage site is in pipelines. To a large extent pipelines can be made in carbon steel as pure, dry CO 2 is essentially non-corrosive. More corrosion-resistant materials or corrosion inhibition must be considered when the CO 2 contains water that condenses out during transportation. This will occur where it is impossible to dry CO 2 to a dew point well below the ambient temperature. Water-saturated CO 2 is corrosive when water precipitates, but experiments exhibit that corrosion rates at high CO 2 pressures in systems containing only water or water/MEG (monoethylene glycol) mixtures are considerably lower than predicted by corrosion models. This applies particularly at low temperatures that are typical for sub-sea pipelines in northern waters. This chapter focuses on determining the corrosion rate as function of CO 2 pressure up to 80 bar. The results are compared to existing corrosion models that have been developed to cover a pressure range relevant for oil and gas transportation, that is, pressures up to 20 bar. The experiments show that the models overestimate the corrosion rate when they are used above their CO 2 partial pressure input limit. At low temperature the models predict more than 10 times the measured corrosion rate. Finally, the results indicate that the corrosion rate has a maximum as function of CO 2 pressure at 40 and 50 ℃. The maximum is at 30-50 bar depending on temperature.

Kjell Ove Kongshaug

Papers

Amine functionalised metal organic frameworks (MOFs) as adsorbents for carbon dioxide

Design, synthesis and characterization of a Pt–Gd metal–organic framework containing potentially catalytically active sites

Design of novel bilayer compounds of the CPO-8 type containing 1D channels.

Synthesis and characterization of CPO-1; three-dimensional coordination polymers with 2,6-naphthalenedicarboxylate (ndc) ligands [M(ndc)(H2O)], M=Mn(II), Zn(II) or Cd(II)

Materials Selection for Capture, Compression, Transport and Injection of CO 2