Supercritical fluid extraction of surfactant from Si‐MCM‐41

Kawi, Sibudjing; Lai, M.W.

doi:10.1002/aic.690480719

Cited by 32 publications

(12 citation statements)

References 33 publications

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“…I -) [2,3]. After the synthesis, surfactant molecules occluded in the pores must be removed, which can be achieved by ultrasound [8], supercritical fluid [9], ozone [10], plasma [11] or microwave [12]. Nevertheless, calcination is the most widely used approach to remove & Cíntia C. Costa natcintia@gmail.com surfactants.…”

Section: Introductionsupporting

confidence: 46%

Kinetic study of the removal of pure and mixed TTMA+, CTMA+ and DTMA+ templates from MCM-41

Costa

Melo

Fontes

et al. 2015

J Therm Anal Calorim

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This work assessed the thermal degradation of surfactants, i.e., tetradecyltrimethylammonium bromide (TTMA ? -C 17 H 38 NBr), cetyltrimethylammonium bromide (CTMA ? -C 19 H 42 NBr) and trimethyloctadecylammonium bromide (DTMA ? -C 21 H 46 NBr), used to obtain MCM-41-type mesoporous materials using Flynn-Wall kinetic model. The cationic surfactants and their mixture at ratios of 1:1 and 1:1:1 resulting materials were labeled C hydrothermal method were characterized by physical, chemical and microstructural analyses such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy, thermogravimetric and nitrogen adsorption-desorption plots (BET). The mesoporous materials showed a well-defined hexagonal arrangement from the calcination process and significant structural differences. The kinetic model was used to determine the apparent activation energy for the removal of pure surfactant and associated with pores of the MCM-41-type molecular sieve. From the kinetic study results, a decrease in activation energy was observed when using the mixture of surfactants, especially C 17 C 19 . Combining these results with XRD and BET analyses, it was observed that C 17 C 19 showed the largest surface area and pore volume along with hexagonal arrangement. The mixture of cationic surfactants of hydrophobic chains of different sizes used in the preparation of MCM-41 reduced the activation energy and surfactant removal.

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Section: Introductionsupporting

confidence: 46%

Kinetic study of the removal of pure and mixed TTMA+, CTMA+ and DTMA+ templates from MCM-41

Costa

Melo

Fontes

et al. 2015

J Therm Anal Calorim

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“…Just like common non-or low-polarity organic solvents, hydrophilic compounds can be solubilized in SFCO 2 with addition of surfactants. While some research groups [22][23][24] are engaged in synthesizing new surfactants having higher solubility in SFCO 2 , others [25][26][27] Four surfactants in this work were found only sparingly soluble in R134a 30 and unable to form reverse micelle for hydrophilic component extraction. Therefore, we attempted to measure the solubilities of these four surfactants in R134a modified by methanol, ethanol, and 2-propanol to explore whether the organic solvents would enhance the surfactant solubilities.…”

Section: Introductionmentioning

confidence: 42%

“…Just like common non-or low-polarity organic solvents, hydrophilic compounds can be solubilized in SFCO 2 with addition of surfactants. While some research groups [22][23][24] are engaged in synthesizing new surfactants having higher solubility in SFCO 2 , others [25][26][27] try to improve the solubility of commercialized surfactants by adding co-solvents. With co-solvents, such as ethanol or pentanol, hydrophilic compounds, for example, methyl orange and riboflavin were readily soluble and extracted using AOT-containing SFCO 2 .…”

Section: Introductionmentioning

confidence: 99%

Solubility Measurements of Surfactants and Dissolution of Cytochrome c in 1,1,1,2‐Tetrafluoroethane Modified with Organic Solvents

2007

J Chinese Chemical Soc

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The solubilities of four surfactants, sodium bis-2-ethylhexyl sulfosuccinate (AOT), cetyltrimethylammonium chloride, didodecyldimethylammonium bromide, and n-dodecyltrimethylammonium chloride in liquid refrigerant 1,1,1,2-tetrafluoroethane (R134a) modified with methanol, ethanol, and 2-propanol were measured. The measurements were performed under 25 and 50 bar at 25°C. The solubility of AOT was as high as 92 mM in R134a with addition of 2% ethanol. Cytochrome c molecules were then verified to be soluble in the AOT-containing and ethanol-modified R134a solution. Accordingly, liquid R134a is suggested as a potential extraction solvent for hydrophilic compounds.

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“…Grieken et al [5] employed SCO 2 with and without organic liquid co-solvent resulting in up to 81% of template removal. Kawi and Lai [16] reported the inability of SCO 2 alone to remove organic template, whereas the addition of methanol or water as co-solvent increased template removal efficiency by 86.3 and 93.6%, respectively. Although the application of SCO 2 with or without organic co-solvent modifier cannot reach 100% organic template removal, it is regarded as a…”

Section: Introductionmentioning

confidence: 48%

Mesoporous silica synthesis in sub- and supercritical carbon dioxide

Chun

Pendleton

Badalyan

et al. 2010

Korean J. Chem. Eng.

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Mesoporous silicas were synthesized from sodium silicate (Na 2 Si 3 O 7 ) and tetraethylorthosilicate (TEOS) with Pluronic F127 (polyethylene oxide-polypropylene oxide-polyethylene oxide, EO 106 PO 70 EO 106 ) triblock copolymer using sub-and supercritical carbon dioxide (SubCO 2 and SCO 2 ) respectively, as solvents. Templates were removed using liquid carbon dioxide (LCO 2 ) and SCO 2 . The most efficient template removal was achieved by LCO 2 -92.7% (w/w), followed by LCO 2 with ethanol entrainer -85.6% (w/w), and by methanol -78.8% (w/w). The best efficiency of template removal by SCO 2 was 50.7%. Values of specific surface areas, A BET , were increased by 10% with the increase of an ageing time from 6 to 24 hours for Na 2 Si 3 O 7 -based silicas at aqueous synthesis conditions, whereas the use of SCO 2 reduced this value by 19.4%. For TEOS-based silicas synthesized using SCO 2 , A BET values increased by 3.8 times. Application of SCO 2 for synthesis of TEOS-based silicas resulted in higher mesopore volumes of 0.719 and 1.241 mL/g with an average mesopore width varying from 3.4 to 3.9 nm. Although Na 2 Si 3 O 7 -based silicas have almost similar mesopore width range, their mesopore volumes were 7 times less than those for TEOS-based silicas. Formation of mesopores in Na 2 Si 3 O 7 -and TEOS-based silicas was at the expense of micropores when synthesized in SCO 2 .

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Supercritical fluid extraction of surfactant from Si‐MCM‐41

Abstract: Supercritical fluid extraction has been carried out on as-synthesized

Cited by 32 publications

References 33 publications

Kinetic study of the removal of pure and mixed TTMA+, CTMA+ and DTMA+ templates from MCM-41

Kinetic study of the removal of pure and mixed TTMA+, CTMA+ and DTMA+ templates from MCM-41

Solubility Measurements of Surfactants and Dissolution of Cytochrome c in 1,1,1,2‐Tetrafluoroethane Modified with Organic Solvents

Mesoporous silica synthesis in sub- and supercritical carbon dioxide

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