Applications supercritical fluids

Keskin, S. and Kayrak-Talay, D. and Akman, U. and Hortacsu, O. (2007). A review of ionic liquids towards supercritical fluid applications. J. of Supercritical Fluids, 43, 150-180. 

Alberto Bertucco (age 46), Professor of Chemical Engineering at the University of Padova, Italy Chairman of the Working Party High Pressure Technology of the European Federation of Chemical Engineers, with long-term research activity in the field of Supercritical Fluids Applications. 

M. Perrut, Supercritical Fluid Applications Industrial Developments and Economic Issues, Proceedings of the 5th International Symposium on Supercritical Fluids, Atlanta, Georgia, USA, 2000. 

Another important aspect of supercritical fluids application is in polymer fractionation, in order to obtain mono-dispersed molecular weights. The simulation of the fractionation of polyethylene from ethylene and hexane solutions into fractions of different molecular weights was proposed by Chen et al. [7]. 

Tomasko DL, Han XM, Liu DH, Gao WH (2003) Supercritical fluid applications in polymer nanocomposites. Curr Opin Solid State Mater Sci 7 407 112... 

Particle design is presently a major development of supercritical fluids applications, mainly in the paint, cosmetic, pharmaceutical, and specialty chemical industries [4CM-2]. The particle formation of functional pigments with biodegradable polymer has been successfully performed by gas-saturated solution (GSS) process using scC02 and PEG in a thermostatted stirred vessel [43]. The average diameter of the particles obtained by GSS at different conditions (40 and 50 °C, 10-30 MPa) is about 0.78-1.472 pm. 

The nature of mixed fluid solvent systems and their role in various supercritical fluid applications is complicated by the increased complexity of the phase behavior. Several different types of mixed fluid phase behavior have been identified (17,18), some of... 

Perrut, M. Supercritical fluid applications Industrial developments and economic issues. Ind. Eng. Chem. Res. 2000, 39, 4531-4535. 

Elvassore N, Sartorello S, Spilimbergo S, Bertucco A. Micro-organisms inactivation by supercritical CO2 in a semicontinuous process. Antibes, France International Society for the Advancement of Supercritical Fluids, 2000 773. Perrut M. Future trends for supercritical fluids. Applications in the pharmaceutical industry. Proceedings of the 6th Conference on Supercritical Fluids and Their Applications, Maiori, Italy, 2001 1-6. 

Standard Guide for Purity of Carbon Dioxide Used in Supercritical Fluid Application. ASTM Designation E 1747-95. West Conshohocken, PA American Society of Testing Materials, 1995. 

Keskin S, Kayrak-Talay D, Akman U et al (2007) A review of ionic liqttids towards supercritical fluid applications. J Supercrit Fluids 43 150-180... 

Particularly evident is the lack of systematic reports on polymer-mixed solvents data (VLE or LLE) in the open hterature, especially in form of full-phase equilibrium measurements. Most experimental studies for mixed solvent systans have been reported by Chinese and Japanese investigators - and only a few by other investigators. Data are often reported simply as soluble/nonsoluble or as theta temperatures (critical solution temperature at infinite polymer molecular weight). Several reported polymer-mixed solvent data concern supercritical fluid applications (e.g., polypropylene/pen-tane/C02, and PEG/C02/cosolvent ) and bioseparations, especially for systems related to the partitioning of biomolecules in aqueons two-phase systems, which contain PEG and dextran. A recent review for data on solnbihty of gases in glassy polymers is also available. ... 

Tbe figure in the patent showing tbe process invention is quite detailed, and the complete description of the operation is quite lengthy and involved. There are no data given SO we conclude that this is a thought patent, but it is presented to show the breadth of supercritical fluid applications. 

With the growth of PTC, various new technologies have been developed where PTC has been combined with other methods of rate enhancement. In some cases, rate enhancements much greater than the sum of the individual effects are observed. Primary systems studied involving the use of PTC with other rate enhancement techniques include the use of metal co-catalysts, sonochemistry, microwaves, electrochemistry, microphases, photochemistry, PTC in single electron transfer (SET) reactions and free radical reactions, and PTC reactions carried out in a supercritical fluid. Applications involving the use of a co-catalyst include co-catalysis by surfactants (Dolling, 1986), alcohols and other weak acids in hydroxide transfer reactions (Dehmlow et al., 1985,1988), use of iodide (traditionally considered a catalyst poison, Hwu et... 

The parameter ky is a non-additive interaction parameter. In nearly all cases we use ky = 1. Our goal is to derive a model for supercritical fluids applicable to a very wide range of states and properties. In order to do so, we have developed an automatic optimization procedure to match a variety of experimental data. 

M. Perrut (2000) Industrial and Engineering Chemical Research, vol. 39, p. 4531 - Supercritical fluid applications industrial developments and economic issues . 

Supercritical fluids (SCFs) are gases at pressure and temperatures (slightly) above those of the vapor-liquid critical point. As the critical pressures of known substances are (much) higher than atmospheric pressure, a supercritical fluid is always a high-pressure gas. The unique property of an SCF is that its density is very sensitive to small changes in pressure and temperature. Density is directly related to many other physical (and chemical) properties of a fluid. The most important in supercritical fluid applications is the solvent power, that is, the ability to dissolve other substances. 

Photoresist stripping and residue removal will probably be the first microelectronics supercritical fluid applications integrated into IC (integrated circuit) processing. 

The particle design is a major development of supercritical fluids applications, with potential applications in the pharmaceutical, food, cosmetic, and some chemical industries. This section presents a concise survey of the published material classified according to the different processing concepts currently used to manufacture particles or other dispersed materials. 

It is believed that the selected systems are representative for systems to be met in supercritical fluid applications. Also it became apparent from this work that in the region of interest for supercritical fluid applications in very narrow concentration windows the nature of the fluid phase behavior sometimes may change several times or, in other words, the number of coexisting phases may change several times from two into three and vice versa. For obvious reasons this makes the design of processes with near-critical carbon dioxide extra complicated since it may be expected that the phenomena discussed in this work are very general and not only limited to the solutes investigated in this study. 

There are many more aspects of supercritical fluids application which have to be investigated before industry will be readily willing to introduce these type of processes, and which probably only can be treated successfully in cooperation with process engineers. Some of these aspects are ... 

K. Nagahama, in Handbook of Supercritical Fluids. Application in Food Industries (in Japanese) (K. Nagahama and I. Suzuki, eds.), p. 18, Science Forum, Tokyo, Japan, 2002. 

Many reviews had shown the importance of IL such as in supercritical fluid applications by Seda Keskin et al. [54]. Measurements of thermochemical properties of imidazolium-based ionic liquid (ILs) carried out has been reported [55]. Tamar L. Greaves et al. [56] explained the properties and applications of protic ILs. Revisiting characteristics of ILs are explained by Rusen Feng [57]. Recently, room-temperature ILs are being used as lubricants [58], i.e., tribology, because ILs possess excellent properties such as non-volatihty, nonflammabiUty, and thermo-oxidative stability. 

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