168 research outputs found
A robust binary supramolecular organic framework (SOF) with high CO2 adsorption and selectivity
A robust binary hydrogen-bonded supramolecular organic framework (SOF-7) has been synthesized by solvothermal reaction of 1,4-bis-(4-(3,5-dicyano-2,6 dipyridyl)dihydropyridyl)benzene (1) and 5,5’-bis-(azanediyl)-oxalyl-diisophthalic acid (2). Single crystal X-ray diffraction analysis shows that SOF-7 comprises 2 and 1,4-bis-(4-(3,5-dicyano-2,6-dipyridyl)pyridyl)benzene (3), the latter formed in situ from the oxidative dehydrogenation of 1. SOF-7 shows a three-dimensional four-fold interpenetrat-ed structure with complementary O−H···N hydrogen bonds to form channels that are decorated with cyano- and amide-groups. SOF-7 exhibits excellent thermal stability and sol-vent and moisture durability, as well as permanent porosity. The activated desolvated material SOF-7a shows high CO2 sorption capacity and selectivity compared with other po-rous organic materials assembled solely through hydrogen bonding
Polymer nanofilms with enhanced microporosity by interfacial polymerization
Highly permeable and selective membranes are desirable for energy-efficient gas and liquid separations. Microporous organic polymers have attracted significant attention in this respect owing to their high porosity, permeability, and molecular selectivity. However, it remains challenging to fabricate selective polymer membranes with controlled microporosity which are stable in solvents. Here we report a new approach to designing crosslinked, rigid polymer nanofilms with enhanced microporosity by manipulating the molecular structure. Ultra-thin polyarylate nanofilms with thickness down to 20 nm were formed in-situ by interfacial polymerisation. Enhanced microporosity and higher interconnectivity of intermolecular network voids, as rationalised by molecular simulations, are achieved by utilising contorted monomers for the interfacial polymerisation. Composite membranes comprising polyarylate nanofilms with enhanced microporosity fabricated in-situ on crosslinked polyimide ultrafiltration membranes show outstanding separation performance in organic solvents, with up to two orders of magnitude higher solvent permeance than membranes fabricated with nanofilms made from noncontorted planar monomers
Pyrene Bearing Azo-Functionalized Porous Nanofibers for CO2 Separation and Toxic Metal Cation Sensing
This article describes the construction of a novel luminescent azo-linked polymer from 1,3,6,8-tetra(4--aminophenyl)pyrene using a copper(I)-catalyzed oxidative homocoupling reaction
Nitrogen-Rich Porous Polymers for Carbon Dioxide and Iodine Sequestration for Environmental Remediation
The use of fossil
fuels for energy production is accompanied by carbon dioxide release
into the environment causing catastrophic climate changes. Meanwhile,
replacing fossil fuels with carbon-free nuclear energy has the potential
to release radioactive iodine during nuclear waste processing and
in case of a nuclear accident. Therefore, developing efficient adsorbents
for carbon dioxide and iodine capture is of great importance. Two
nitrogen-rich porous polymers (NRPPs) derived from 4-bis-(2,4-diamino-1,3,5-triazine)-benzene
building block were prepared and tested for use in CO<sub>2</sub> and
I<sub>2</sub> capture. Copolymerization of 1,4-bis-(2,4-diamino-1,3,5-triazine)-benzene
with terephthalaldehyde and 1,3,5-trisÂ(4-formylphenyl)Âbenzene in dimethyl
sulfoxide at 180 °C afforded highly porous NRPP-1 (SA<sub>BET</sub> = 1579 m<sup>2</sup> g<sup>–1</sup>) and NRPP-2 (SA<sub>BET</sub> = 1028 m<sup>2</sup> g<sup>–1</sup>), respectively. The combination
of high nitrogen content, π-electron conjugated structure, and
microporosity makes NRPPs very effective in CO<sub>2</sub> uptake
and I<sub>2</sub> capture. NRPPs exhibit high CO<sub>2</sub> uptakes
(NRPP-1, 6.1 mmol g<sup>–1</sup> and NRPP-2, 7.06 mmol g<sup>–1</sup>) at 273 K and 1.0 bar. The 7.06 mmol g<sup>–1</sup> CO<sub>2</sub> uptake by NRPP-2 is the second highest value reported
to date for porous organic polymers. According to vapor iodine uptake
studies, the polymers display high capacity and rapid reversible uptake
release for I<sub>2</sub> (NRPP-1, 192 wt % and NRPP-2, 222 wt %).
Our studies show that the green nature (metal-free) of NRPPs and their
effective capture of CO<sub>2</sub> and I<sub>2</sub> make this class
of porous materials promising for environmental remediation
Effective Approach for Increasing the Heteroatom Doping Levels of Porous Carbons for Superior CO<sub>2</sub> Capture and Separation Performance
Development
of efficient sorbents for carbon dioxide (CO<sub>2</sub>) capture
from flue gas or its removal from natural gas and landfill gas is
very important for environmental protection. A new series of heteroatom-doped
porous carbon was synthesized directly from pyrazole/KOH by thermolysis.
The resulting pyrazole-derived carbons (PYDCs) are highly doped with
nitrogen (14.9–15.5 wt %) as a result of the high nitrogen-to-carbon
ratio in pyrazole (43 wt %) and also have a high oxygen content (16.4–18.4
wt %). PYDCs have a high surface area (SA<sub>BET</sub> = 1266–2013
m<sup>2</sup> g<sup>–1</sup>), high CO<sub>2</sub> <i>Q</i><sub>st</sub> (33.2–37.1 kJ mol<sup>–1</sup>), and a combination of mesoporous and microporous pores. PYDCs exhibit
significantly high CO<sub>2</sub> uptakes that reach 2.15 and 6.06
mmol g<sup>–1</sup> at 0.15 and 1 bar, respectively, at 298
K. At 273 K, the CO<sub>2</sub> uptake improves to 3.7 and 8.59 mmol
g<sup>–1</sup> at 0.15 and 1 bar, respectively. The reported
porous carbons also show significantly high adsorption selectivity
for CO<sub>2</sub>/N<sub>2</sub> (128) and CO<sub>2</sub>/CH<sub>4</sub> (13.4) according to ideal adsorbed solution theory calculations
at 298 K. Gas breakthrough studies of CO<sub>2</sub>/N<sub>2</sub> (10:90) at 298 K showed that PYDCs display excellent separation
properties. The ability to tailor the physical properties of PYDCs
as well as their chemical composition provides an effective strategy
for designing efficient CO<sub>2</sub> sorbents
An Accurate Force Field Model for the Strain Energy Analysis of the Covalent Organic Framework COF-102
Film growth precursor development for metal nitrides. Synthesis, structure, and volatility of molybdenum(vi) and tungsten(vi) complexes containing bis(imido)metal fragments and various nitrogen donor ligands
Volatility Enhancement in Calcium, Strontium, and Barium Complexes Containing β-Diketiminate Ligands with Dimethylamino Groups on the Ligand Core Nitrogen Atoms
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