Synthesis of Sidechain Free Hydrazone-Linked Covalent Organic Frameworks Through Supercritical Carbon Dioxide Activation

Narrow Range ◽

High Surface ◽

Covalent Organic Frameworks ◽

Surface Areas ◽

Carbon Dioxide Activation ◽

Supercritical carbon dioxide (scCO2) activation provides milder conditions to process covalent organic frameworks (COFs) without compromising their crystallinity and porosity. To this end, three hydrazone COFs (TFPB-DHz COF, TFPT-DHz COF, Py-DHz COF) were synthesized with a terephthaloyl dihydrazide linker (DHz) which has no substituents. To date, the synthesis of hydrazone COFs without a narrow range of alkoxy linkers has not been possible. The scCO2 activated hydrazone-linked COFs in this study were crystalline and had high surface areas (TFPB-DHz COF, TFPT-DHz COF and Py-DHz COF were 790 m²/g, 1199 m²/g, and 932 m²/g, respectively). This study shows the significance of using milder activation methods for making hydrazone-linked COF structures that were previously inaccessible.

One-Pot Procedure to Synthesize High Surface Area Alumina Nanofibers Using Supercritical Carbon Dioxide

Langmuir ◽

10.1021/la902738y ◽

2010 ◽

Vol 26 (4) ◽

pp. 2707-2713 ◽

Cited By ~ 35

Author(s):

Muhammad B. I. Chowdhury ◽

Rouhong Sui ◽

Rahima A. Lucky ◽

Paul A. Charpentier

Keyword(s):

Carbon Dioxide ◽

Surface Area ◽

High Surface ◽

High Surface Area ◽

One Pot ◽

Alumina Nanofibers ◽

Preparation of Semi-Conducting Polymeric Nanoparticles by Supercritical Carbon Dioxide RESOLV Process

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2008.ic13 ◽

2008 ◽

Vol 8 (9) ◽

pp. 4707-4710 ◽

Cited By ~ 6

Author(s):

Hullathy Subban Ganapathy ◽

Jun Ho Kim ◽

Seung-Soo Hong ◽

Kwon Taek Lim

Keyword(s):

Carbon Dioxide ◽

Polymeric Nanoparticles ◽

High Surface ◽

Sodium Dodecyl ◽

Rapid Expansion ◽

Environmentally Benign ◽

Spherical Nanoparticles ◽

Average Size ◽

The rapid expansion of supercritical carbon dioxide solutions into a liquid solvent (RESOLV) technique with environmentally benign supercritical carbon dioxide was used to produce semi-conducting polymeric nanoparticles of fluoroalkyl ester substituted thiophenes. When the supercritical solutions of the conjugated polymer, poly[2-(3-thienyl) acetyl-3,3,4,4,5,5,6,6,7,7,8,8,8, tridecafluoro-1-octanate] (PSFTE) were expanded into aqueous solutions through a small capillarynozzle (150 μm), spherical nanoparticles in the range of 50–100 nm were obtained. However, after 15 min of expansion, the particles tended to aggregate to form larger objects due to the high surface energy of the polymeric nanoparticles. In order to prevent the agglomeration of particles, a relatively low concentration of sodium dodecyl sulphate (SDS) or NaCl was used as a stabilizing agent in aqueous solution. While NaCl did not give enough stabilization to the system, uniform spherical nanoparticles of PSFTE having an average size of 45 nm were successfully obtained by SDS stabilization.

Cuboctahedron-based indium–organic frameworks for gas sorption and selective cation exchange

Chemical Communications ◽

10.1039/c6cc03497g ◽

2016 ◽

Vol 52 (51) ◽

pp. 7978-7981 ◽

Cited By ~ 29

Author(s):

Panpan Yu ◽

Qipeng Li ◽

Yue Hu ◽

Nannan Liu ◽

Lijie Zhang ◽

...

Keyword(s):

Carbon Dioxide ◽

Methylene Blue ◽

Cation Exchange ◽

Sorption Capacity ◽

Activation Process ◽

Gas Sorption ◽

Carbon Dioxide Activation ◽

Organic Framework ◽

InOF-9is an anionic indium–organic framework, which exhibits excellent gas sorption capacity through supercritical carbon dioxide activation process and selectively encapsulates guest methylene blue cations.

Response of a Compact Recuperator to Thermal Transients in a Supercritical Carbon Dioxide Brayton Cycle

Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy ◽

10.1115/gt2017-63058 ◽

2017 ◽

Author(s):

Eric M. Clementoni ◽

Timothy L. Cox ◽

Martha A. King

Keyword(s):

Carbon Dioxide ◽

Heat Exchangers ◽

High Surface ◽

Integrated System ◽

Compact Heat Exchangers ◽

Power Cycle ◽

Thermal Transients ◽

Wide Range ◽

Supercritical carbon dioxide (sCO2) power cycle designs are typically highly recuperated, transferring heat from the high temperature turbine exhaust stream to the compressor discharge stream thereby increasing overall cycle efficiency. Compact heat exchangers are preferred for this application due to their high surface area-to-volume ratio enabling much smaller heat exchangers as compared to conventional designs. However, compact heat exchangers have a higher metal density than conventional heat exchangers which could result in thermal lag during rapid temperature transients. The Naval Nuclear Laboratory has been operating the Integrated System Test (IST) with the objective of demonstrating the ability to operate and control an sCO2 Brayton power cycle over a wide range of conditions. Rapid turbomachinery startups and power transients result in thermal transients on the recuperator. This paper presents thermal transients observed in the IST recuperator during loop startup and power transients and illustrates the time to achieve thermal equilibrium following the transients.