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| Home > JCE Print > Journal of Chemical Education > Issues >
1999
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January
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In the Laboratory
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Determination of the Critical Micelle Concentration of Cationic Surfactants: An Undergraduate Experiment
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Xirong Huang, Jinghe Yang, Wenjuan Zhang, Zhenyu Zhang, and Zesheng An
Shandong University, Department of Chemistry, Jinan 250100, P. R. CHINA
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January 1999
Vol. 76 No. 1
p. 93
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| Abstract |
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A novel method based on the catalytic effect of micelles exerted by cetyltrimethylammonium bromide (CTAB) and cetylpyridinium bromide (CPB), respectively, on the indicator reaction between H2O2 and bromopyrogallol red (BPR), a triphenylmethane dye, was developed for undergraduates to determine the critical micelle concentration (cmc) of CTAB and CPB. The indicator reaction was monitored by a fixed-time kinetic-spectrophotometric technique. Under the experimental conditions the cmc values of CTAB and CPB were (4.8 ± 0.3) x 10-4 mol/L and (4.5 ± 0.3) x 10-4mol/L, which were close to the literature values of 9.2 x 10-4 mol/L and 9.0 x 10-4 mol/L, respectively. Detailed discussion on the selection of experimental conditions was made to minimize the effect of electrolytes on the cmc's of surfactants and to maintain the high accuracy of the experimental data. As an undergraduate physicochemical laboratory experiment the present method had several attractive features. The procedure is simple and easy to perform, does not require special equipment, and does not need expensive or toxic reagents. In addition, it is a versatile method that can be applied to a wide variety of both anionic and cationic surfactants.
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| More Information |
 Citation |
Huang, Xirong; Yang, Jinghe; Zhang, Wenjuan; Zhang, Zhenyu; An, Zesheng. J. Chem. Educ. 1999 76 93.
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Keywords |
Laboratory Instruction; Physical Chemistry; Dyes; Micelles; Catalysis; UV-Vis Spectroscopy
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History |
Created:
Last Updated: |
June 15, 1999
June 22, 2005
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| Home > JCE Print > Journal of Chemical Education > Issues >
1999
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January
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93
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