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Journal of Chemistry
Volume 2015, Article ID 957950, 10 pages
http://dx.doi.org/10.1155/2015/957950
Research Article

Acid Hydrolysis of Bromazepam Catalyzed by Micelles, Reverse Micelles, and Microemulsions

1Department of Chemistry, University of Dhaka, Dhaka 1000, Bangladesh
2University Grants Commission of Bangladesh, 29/1 Agargaon, Dhaka 1207, Bangladesh

Received 9 December 2014; Revised 25 February 2015; Accepted 9 March 2015

Academic Editor: Yaorong Zheng

Copyright © 2015 Ferdousi Begum et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Kinetics of the acid hydrolysis of bromazepam (Bz) has been investigated in micelles, reverse micelles, and microemulcions of cetyltrimethylammonium bromide (CTAB) by spectrophotometric method. The rate of the acid hydrolysis of Bz was found to be enhanced both below and above the critical micelle concentration (CMC) of CTAB in aqueous solution. The pseudo-first-order rate constant () shows an initial decrease for both low and high H+ concentrations. With further increase in [CTAB], at low [H+], the attains an almost constant value, while, at high [H+], the passes through a maximum and then decreases. The kinetic data for catalysis by micelles of CTAB was interpreted with the pseudophase ion exchange (PIE) model. In CTAB/cyclohexane/1-butanol/water microemulsions, as the water to surfactant ratio () increases, the physicochemical properties and droplet sizes of microemulsions significantly change and distinct changes in reaction environment can be marked. The rate of the hydrolysis reaction exhibits excellent correlation with the physicochemical properties and droplet sizes of the microemulsions and reverse micelles of CTAB. At [H+] = 0.001 M, in reverse micelles and microemulsions of CTAB, the of the acid hydrolysis of Bz decreases sharply followed by a slight increase with increasing .