Use of MEKC for the analysis of reactant and product of Baylis-Hillman reaction.

Li Qi, Kai Cui, Juan Qiao, Gengliang Yang, Yi Chen

Index: J. Sep. Sci. 32(9) , 1480-6, (2009)

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Abstract

A facile, fast and high efficiency micellar EKC has been explored for the analysis and UV detection of p-nitrobenzaldehyde and 2-[hydroxy(4-nitrophenyl)methyl]-2-cyclopenten-1-one with a buffer electrolyte of 30.0 mM tetraborate and 50.0 mM sodium taurodeoxycholate at pH 9.3. Under the optimal conditions, a linear range from 7.8x10(-2) to 5.0x10(2) mM for those analytes (r(2) > 0.99) was achieved. The LOD was 3.9 microM for 2-[hydroxy(4-nitrophenyl)methyl]-2-cyclopenten-1-one and 7.8 microM for p-nitrobenzaldehyde, respectively (S/N = 3). The applicability of this new method for the analysis of reactants (p-nitrobenzaldehyde and cyclopent-2-enone), catalysts (imidazole or N-methyl imidazole or 1-benzyl-imidazole) and product (2-[hydroxy(4-nitrophenyl)methyl]-2-cyclopenten-1-one) on offline Baylis-Hillman reaction was examined. The relationship between the reaction time and the amount of product has been studied. Meanwhile, three different kinds of catalysts were investigated for getting the desired moderate to good amount products. It was found that comparing with N-methyl imidazole or 1-benzyl-imidazole catalyst, imidazole-catalyzed reaction could produce more products within the same reaction time. Furthermore, the results indicated that the rate law for the investigated Baylis-Hillman reaction was second-order reaction. The rate constant for the reaction is 1.34 (+/-0.01)x10(-3) mol(-1) m(3)/s.