物理化学学报 >> 2008, Vol. 24 >> Issue (12): 2207-2213.doi: 10.1016/S1872-1508(08)60084-4

研究论文 上一篇    下一篇

阳离子胶束对[Gr(III)-(Gly-Gly)]2+与茚三酮反应动力学的影响

AKRA MMohd, ZAIDI Neelam Hazoor, KABIR-UD-DIN   

  1. Department of Chemistry, Aligarh Muslim University, Aligarh-202002, India
  • 收稿日期:2008-06-02 修回日期:2008-09-10 发布日期:2008-12-04
  • 通讯作者: KABIR-UD-DIN E-mail:kabir7@rediffmail.com

Effect of Cationic Micelles on the Kinetics of Interaction of [Cr(III)-Gly-Gly]2+ with Ninhydrin

AKRA MMohd, ZAIDI Neelam Hazoor, KABIR-UD-DIN   

  1. Department of Chemistry, Aligarh Muslim University, Aligarh-202002, India
  • Received:2008-06-02 Revised:2008-09-10 Published:2008-12-04
  • Contact: KABIR-UD-DIN E-mail:kabir7@rediffmail.com

摘要: The effect of cationic micelles of cetyltrimethylammonium bromide (CTAB) on the interaction of chromium dipeptide complex ([Cr(III)-Gly-Gly]2+) with ninhydrin under varying conditions has been investigated. The rates of the reaction were determined in both water and surfactant micelles in the absence and presence of various organic and inorganic salts at 70 ℃ and pH 5.0. The reaction followed first-and fractional-order kinetics with respect to [Cr(III)-Gly-Gly2+] and [ninhydrin]. Increase in the total concentration of CTAB from0 to 40×10-3mol·dm-3 resulted in an increase in the pseudo-first-order rate constant (kψ) by a factor of ca 3. Quantitative kinetic analysis of kψ-[CTAB] data was performed on the basis of the pseudo-phase model of the micelles. As added salts induce structural changes in micellar systems that may modify the substrate-surfactant interactions, the effect of some inorganic (NaBr, NaCl, Na2SO4) and organic (NaBenz, NaSal, NaTos) salts on the rate was also explored. It was found that the tightly bound counterions (derived fromorganic salts) were the most effective.

关键词: Micelle, Ninhydrin, Kinetics, Salts, [Cr(III)-Gly-Gly]2+, CTAB

Abstract: The effect of cationic micelles of cetyltrimethylammonium bromide (CTAB) on the interaction of chromium dipeptide complex ([Cr(III)-Gly-Gly]2+) with ninhydrin under varying conditions has been investigated. The rates of the reaction were determined in both water and surfactant micelles in the absence and presence of various organic and inorganic salts at 70 ℃ and pH 5.0. The reaction followed first-and fractional-order kinetics with respect to [Cr(III)-Gly-Gly2+] and [ninhydrin]. Increase in the total concentration of CTAB from0 to 40×10-3mol·dm-3 resulted in an increase in the pseudo-first-order rate constant (kψ) by a factor of ca 3. Quantitative kinetic analysis of kψ-[CTAB] data was performed on the basis of the pseudo-phase model of the micelles. As added salts induce structural changes in micellar systems that may modify the substrate-surfactant interactions, the effect of some inorganic (NaBr, NaCl, Na2SO4) and organic (NaBenz, NaSal, NaTos) salts on the rate was also explored. It was found that the tightly bound counterions (derived fromorganic salts) were the most effective.

Key words: Micelle, Ninhydrin, Kinetics, Salts, [Cr(III)-Gly-Gly]2+, CTAB

MSC2000: 

  • O648