EFFECTS OF TETRAALKYLAMMONIUM SALTS ON ALKALINE HYDROLYSIS OF N-(2-METHOXYPHENYL) PHTHALIMIDE

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Sim Yoke Leng
M. Niyaz Khan
Azhar Ariffin

Abstract

The effects of the concentrations of Me₄NCI, Pr₄NCl, Bu₄NCl, Me₄NBr, Pr₄NBr and Bu₄NBr on the rate of alkaline hydrolysis of N-(2-methoxyphenyl)phthalimide (N-2MPhPT) at 35°C and in H₂0 solvent containing 2 % (v/v) CH₃CN reveal the formation of ion-pair complexes between solvent - separated loose ion-pair forms ($M^n^+$ ⋯ $X^k^-$) and N-2MPhPT. The bulky hydrophobic tails of tetraalkylammonium salts and their halide anions inhibit the reaction by blocking the OH⻠nucleophilic attack on the reactive site of N-2MPhPT. Among all the quaternary ammonium salts, Me₄NCI showed slight inhibition only because of the shielding effect created by the methyl group is very small. However, Bu₄NBr presents the greatest inhibition on hydrolysis rate because of its strong binding affmity with N-2MPhPT.The effects of the concentrations of Me₄NCI, Pr₄NCl, Bu₄NCl, Me₄NBr, Pr₄NBr and Bu₄NBr on the rate of alkaline hydrolysis of N-(2-methoxyphenyl)phthalimide (N-2MPhPT) at 35°C and in H₂0 solvent containing 2 % (v/v) CH₃CN reveal the formation of ion-pair complexes between solvent - separated loose ion-pair forms ($M^n^+$ ⋯ $X^k^-$) and N-2MPhPT. The bulky hydrophobic tails of tetraalkylammonium salts and their halide anions inhibit the reaction by blocking the OH⻠nucleophilic attack on the reactive site of N-2MPhPT. Among all the quaternary ammonium salts, Me₄NCI showed slight inhibition only because of the shielding effect created by the methyl group is very small. However, Bu₄NBr presents the greatest inhibition on hydrolysis rate because of its strong binding affmity with N-2MPhPT.

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How to Cite
Yoke Leng, S., Khan, M. N., & Ariffin, A. (2004). EFFECTS OF TETRAALKYLAMMONIUM SALTS ON ALKALINE HYDROLYSIS OF N-(2-METHOXYPHENYL) PHTHALIMIDE. Malaysian Journal of Science, 23(2), 175–180. Retrieved from http://ojie.um.edu.my/index.php/MJS/article/view/8459
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