Homogeneous Catalysis in Supercritical Fluids:  Hydrogenation of Supercritical Carbon Dioxide to Formic Acid, Alkyl Formates, and Formamides

1996 ◽  
Vol 118 (2) ◽  
pp. 344-355 ◽  
Author(s):  
Philip G. Jessop ◽  
Yi Hsiao ◽  
Takao Ikariya ◽  
Ryoji Noyori
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Formic Acid ◽  
Homogeneous Catalysis ◽  
Supercritical Fluids ◽  
Supercritical Carbon

The Influence of Temperature and Concentration on Copper Deposition Kinetics in Supercritical Carbon Dioxide

2004 ◽  
Vol 812 ◽  
Author(s):  
Yinfeng Zong ◽  
James J. Watkins
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Supercritical Fluids ◽  
Zero Order ◽  
Copper Deposition ◽  
Deposition Kinetics ◽  
Zero Order Kinetics ◽  
Concentration Interval ◽  
Kinetics Of ◽  
Supercritical Carbon

AbstractThe kinetics of copper deposition by the hydrogen-assisted reduction of bis(2,2,7- trimethyloctane-3,5-dionato)copper in supercritical carbon dioxide was studied as a function of temperature and precursor concentration. The growth rate was found to be as high as 31.5 nm/min. Experiments between 220 °C and 270 °C indicated an apparent activation energy of 51.9 kJ/mol. The deposition kinetics were zero order with respect to precursor at 250 °C and 134 bar and precursor concentrations between 0.016 and 0.38 wt.% in CO2. Zero order kinetics over this large concentration interval likely contributes to the exceptional step coverage obtained from Cu depositions from supercritical fluids.

Generation and Propagation of Thermally Induced Acoustic Waves in Supercritical Fluids: Numerical and Experimental Results

2010 ◽  
Author(s):  
Bakhtier Farouk ◽  
Zhieheng Lei
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Supercritical Fluid ◽  
Supercritical Fluids ◽  
Acoustic Waves ◽  
Rapid Heating ◽  
Time Dependent ◽  
Cylindrical Chamber ◽  
Thermally Induced ◽  
Supercritical Carbon

The behavior of thermally induced acoustic waves generated by the rapid heating of a bounding solid wall in a closed cylindrical chamber filled with supercritical carbon dioxide is investigated numerically and experimentally. A time-dependent one-dimensional problem is considered for the numerical simulations where the supercritical fluid is contained between two parallel plates. The NIST Reference Database 12 is used to obtain the property relations for supercritical carbon dioxide. The thermally induced pressure (acoustic) waves undergo repeated reflections at the two confining walls and gradually dissipate. The numerically predicted temperature of the bulk supercritical fluid is found to increase homogeneously (the so called piston effect) within the domain. The details of generation, propagation and dissipation of thermally induced acoustic waves in supercritical fluids are presented under different heating rates. In the experiments, a resistance-capacitance circuit is used to generate a rapid temperature increase in a thin metal foil located at one end of a closed cylindrical chamber. The time-dependent pressure variation in the chamber and the temperature history at the foil are recorded by a fast response measurement system. Both the experimental and numerical studies predict similar pressure wave shapes and profiles due to rapid heating of a wall.

Design Principles of Surfactants for Polymerization in Supercritical CO2

2016 ◽  
Vol 852 ◽  
pp. 766-769
Author(s):  
Shi Ping Zhan ◽  
Qing Chun Qi ◽  
Qi Cheng Zhao ◽  
Shu Hua Chen ◽  
Wei Min Hou ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Supercritical Fluids ◽  
Design Principle ◽  
Design Principles ◽  
Supercritical Carbon

In recent years, supercritical carbon dioxide, as a green chemical solvent, is widely used. The surfactants for polymerization in supercritical fluids have become one of the important issues. This paper mainly discusses the mechanism and influence of the surfactants in supercritical carbon dioxide system. The choice and design principle of surfactants and the recent development of surfactants were introduced in detail.

Metallic ruthenium nanoparticles for hydrogenation of supercritical carbon dioxide

2016 ◽  
Vol 6 (2) ◽  
pp. 409-412 ◽  
Author(s):  
T. Umegaki ◽  
Y. Enomoto ◽  
Y. Kojima
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Formic Acid ◽  
High Activity ◽  
Methyl Alcohol ◽  
Alcohol Solution ◽  
Ruthenium Nanoparticles ◽  
Solvothermal Conditions ◽  
Supercritical Carbon

Metallic ruthenium nanoparticles prepared in a methyl alcohol solution under solvothermal conditions showed high activity for hydrogenation of supercritical carbon dioxide to formic acid.

Production of Microsphere Polystyrene Using Solution Enhanced Dispersion by CO2 Supercritical Fluids (SEDS)

2019 ◽  
Vol 805 ◽  
pp. 146-152
Author(s):  
Achmad Chafidz ◽  
Umi Rofiqah ◽  
Sumarno ◽  
Megawati ◽  
Mujtahid Kaavessina ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Size Distribution ◽  
Supercritical Fluids ◽  
Atmospheric Condition ◽  
Average Diameter ◽  
Solution Flow ◽  
Polystyrene Solution ◽  
Annulus Diameter ◽  
Supercritical Carbon

Supercritical fluids (SCFs) process can be considered as an emerging ”clean“ technology for the production of small-size particles (e.g. micron-size). Microsphere is a material in micron scale which has been widely used as adsorbent, catalyst support, and drug delivery system. For advanced application, those materials are formulated in the form of porous microspheres. There are several methods that can be used using SCFs. One of them is Solution Enhanced Dispersion by Supercritical Fluids (SEDS). This method is considered to be suitable in obtaining the porous microsphere polystyrene. In this study, polystyrene was first dissolved into toluene (polystyrene solution) at different concentrations (i.e. 3, 5, 7, 9, 11, 13, 15 wt%) and then blown/sprayed together with supercritical carbon dioxide (CO2) through co-axial nozzle with two differents annulus diameter (i.e. 3.6 mm and 4.6 mm). Co-axial nozzle consists of two concentric pipes, inner pipe and annulus. Inner pipe for polystyrene solution flow and annulus for supercritical carbon dioxide flow. The expansion of these two of fluid was done both in atmospheric condition and in pressurized precipitator (40 bar). The resulted microsphere was analyzed by using SEM (Scanning Electron Microscope) to determine morphology and average diameter of the microsphere. The SEM analysis results showe that the smaller the initial concentration of solution used, the resulted microspheres tend to be smaller and less fibrils formed. Additionally, in the pressurized precipitator, the formed microspheres size was smaller and size distribution more narrow than that of atmospheric condition. Moreover, the use of smaller annulus diameter in co-axial nozzle produced smaller microsphere size and the size distribution was more uniform.

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