In the sol gel production of high surface area catalyst, the template, a surfactant, is
the key component of the process. A template too soluble in the supercritical dryingextraction
process can yield a catalyst with a lower surface area. A template completely
insoluble in the supercritical drying-extraction process can lead to a longer calcinations
step and lower catalyst surface area. Template recovery also enhances the economic
feasibility of plant scale production of high surface area catalyst. For these reasons
knowing surfactant solubility in supercritical media is important.
The solubility of surfactants tert-octylphenoxypolyethoxyethanol (commercially
available and hereafter referred to as Triton X-114) and alkyloxypolyethyleneoxyethanol
(commercially available and hereafter referred to as Tergitol 15-S-9) in supercritical
carbon dioxide and ethanol entrainer have been determined at five-degree increments
from 35
oC to 50oC. The solubility of the surfactants was determined by charging a
variable volume cloud point system with the entrainer-surfactant mixture followed by
liquid carbon dioxide. With the resulting stirred homogeneous mixture heated to
temperature, cloud point pressures were observed as the phase analyzer cell was
pressurized by adjusting the variable volume. An average of five values for cloud point
pressure is reported here. The mixture behaviors were modeled using the Improved
Rackett equation and the Peng-Robinson-Stryjek-Vera (PRSV) equation of state with
Wong-Sandler (WS) mixing rules.
For the Carbon Dioxide (CO
2) (1) – Ethanol/Triton X-114 (2) mixtures studied,
compositions ranged from 93.2 mol% CO
2 to 97.7 mol% CO2. The solubility of Triton
X-114 ranged from 0.02 mol% to 0.05 mol% at temperatures ranging from 35
oC to 50oC.
Cloud point pressures observed for this system range from 95 bar to 143 bar.
For the CO
2 (1) – Ethanol/Tergitol 15-S-9 (2) mixtures studied, compositions
ranged from 92.3 mol% CO
2 to 94.4 mol % CO2. The solubility of Tergitol 15-S-9
ranged from 0.02 mol% to 0.03mol% at temperatures ranging from 35
oC to 50oC. Cloud
point pressures observed for this system range from 89 to 154 bar.
| Identifer | oai:union.ndltd.org:USF/oai:scholarcommons.usf.edu:etd-5021 |
| Date | 08 December 2005 |
| Creators | Smeltzer, Brandon |
| Publisher | Scholar Commons |
| Source Sets | University of South Flordia |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Graduate Theses and Dissertations |
| Rights | default |
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