کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
7831774 | 1503276 | 2008 | 7 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Micelle Catalyzed Oxidation of D-Mannose by Cerium (IV) in Sulfuric Acid
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
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چکیده انگلیسی
Kinetics of D-mannose oxidation by cerium (IV) was studied in a sulfuric acid medium at 40°C both in absence and presence of ionic micelles. In both cases, the rate of the reaction was first-order in D-mannose and cerium (IV), which decreased with increasing [H2SO4]. This suggested that the redox reaction followed the same mechanism. The reaction proceeded through formation of an intermediate complex, which was proved by kinetic method. The complex underwent slow unimolecular decomposition to a free radical that reacted with cerium (IV) to afford the product. The catalytic role of cationic cetyltrimethylammonium bromide (CTAB) micelles was best explained by the Menger-Portnoy model. The study of the effect of CTAB also indicated that a negatively charged species was the reactive form of cerium (IV). From the kinetic data, micelle-cerium (IV) binding and rate constants in micellar medium were evaluated. The anionic micelle of sodium dodecyl sulfate plays no catalytic role. The oxidation has the rate expression:
-d[Ce(IV)]=k1Kc1[D-mannose][Ce(IV)]dt Different activation parameters for micelle catalyzed and uncatalyzed paths were also calculated and discussed.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Acta Physico-Chimica Sinica - Volume 24, Issue 5, May 2008, Pages 810-816
Journal: Acta Physico-Chimica Sinica - Volume 24, Issue 5, May 2008, Pages 810-816
نویسندگان
Kabir-ud-Din Kabir-ud-Din, Mohd. Sajid Ali, Zaheer Khan,