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A novel process for precipitation of ultra-fine particles using sub-critical CO(2)

DSpace at IIT Bombay

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Title A novel process for precipitation of ultra-fine particles using sub-critical CO(2)
 
Creator DALVI, SV
MUKHOPADHYAY, M
 
Subject compressed fluid antisolvent
ress-sc process
rapid expansion
supercritical solutions
carbon-dioxide
behavior
crystallization
cholesterol
mixtures
crystals
zinc acetate
nanoparticles
depressurization
temperature reduction
sub-critical co(2)
gas-expanded liquids
 
Description Supercritical CO(2) has been utilized as solvent. cosolvent or antisolvent in several processes for production of ultra-fine solid particles with narrow size distribution. The key to the precipitation of such particles is to produce a very large, rapid and uniform supersaturation in the solution of a solid substance. This can be achieved either by a rapid and large reduction in the temperature of solution or by drastically increasing the CO(2) solubility for imparting the antisolvent effect. Most of these CO(2) processes require high-pressure pumps, specially designed nozzles and accurate control of process parameters. In order to obviate these requirements, a simple technique of precipitation by pressure reduction over the gas-expanded liquids (PPRGEL), such as CO(2)-expanded organic solutions has been utilized to impart a large. uniform and rapid reduction of temperature in the solution for instantaneous precipitation of ultra-fine particles. This process utilizes sub-critical CO(2) at relatively low pressures of 40-70 bar and near ambient temperature of 303 K for creating a temperature drop of 30-70 K in the solution within seconds, without using any specially designed nozzle or high-pressure pumps. The present paper validates the process principle for precipitation of Zinc acetate (ZnAc) nanoparticles from its organic solution in a mixed solvent of acetone and dimethyl sulfoxide (DMSO). Nanoparticles are produced with the average size of 20-250 nm (from 100 ml of solution in a high-pressure vessel of 1.09 L working volume), and vary in shapes such as long needles, rods and near spherical depending on pressure (40-70 bar at 303 K), solid concentration (0.01-0.05 g/ml) and addition of stabilizer. (c) 2009
 
Publisher ELSEVIER SCIENCE SA
 
Date 2011-07-27T14:45:27Z
2011-12-26T12:57:28Z
2011-12-27T05:41:55Z
2011-07-27T14:45:27Z
2011-12-26T12:57:28Z
2011-12-27T05:41:55Z
2009
 
Type Article
 
Identifier POWDER TECHNOLOGY, 195(3), 190-195
0032-5910
http://dx.doi.org/10.1016/j.powtec.2009.05.029
http://dspace.library.iitb.ac.in/xmlui/handle/10054/7251
http://hdl.handle.net/10054/7251
 
Language en