کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
9676124 1454115 2005 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Kinetics of complexation of lanthanide ions by 3-methyl-4-acyl-5-pyrazolone derivatives in micellar and microemulsion media
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی شیمی کلوئیدی و سطحی
پیش نمایش صفحه اول مقاله
Kinetics of complexation of lanthanide ions by 3-methyl-4-acyl-5-pyrazolone derivatives in micellar and microemulsion media
چکیده انگلیسی
The stopped-flow technique has been used to investigate the kinetics of complexation of two metal ions representative of the lanthanide series (namely Eu(III) and Lu(III)) by hydrophobic pyrazolones, in micellar solutions of CTAB and in microemulsions of CTAB/butanol/water/heptane (or toluene). Two pyrazolone derivatives having very different pK's were concerned: 1-p-nitrophenyl-3-methyl-4-p-octylbenzoyl-5-pyrazolone (HNPMOBP) and 1-phenyl-3-methyl-4-lauroyl-5-pyrazolone (HPMLP). The influence of parameters such as ionic strength, pH, and temperature or metal ion concentration was studied. Depending on the conditions one or two kinetic processes were observed. The first process associated with the ligand/metal reaction was taken into account by a simple mechanism assuming that the reactive species is the anionic form of the ligand. The values of the apparent formation rate constants obtained in these microheterogeneous media were compared with values from the literature in homogeneous solutions. Complexation with Eu(III) was about an order of magnitude faster than with Lu(III), suggesting that it is controlled by the departure of water molecules from the metal solvation shell. The reaction was considerably faster with HNPMOBP compared to HPMLP. No significant partitioning effect could be demonstrated by adding microemulsified heptane or toluene.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Colloids and Surfaces A: Physicochemical and Engineering Aspects - Volume 253, Issues 1–3, 1 February 2005, Pages 95-104
نویسندگان
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