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The Photokinetics of Electron Transfer Reaction of Methylene Blue with Titanium Trichloride in Aqueous–Alcoholic Solvents
Author(s) -
Nadeem Syed Muhammad Saqib,
Saeed Rehana
Publication year - 2017
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.201700112
Subject(s) - chemistry , aqueous solution , enthalpy , arrhenius equation , quantum yield , inorganic chemistry , activation energy , titanium , reaction rate , methylene blue , entropy of activation , kinetics , reaction mechanism , methylene , chemical kinetics , yield (engineering) , reaction rate constant , photochemistry , catalysis , organic chemistry , photocatalysis , thermodynamics , physics , quantum mechanics , fluorescence
The kinetics of photoinduced electron transfer reaction of methylene blue (MB) and titanium trichloride was investigated in water and different aqueous–alcoholic solvents. The reaction is pseudo‐first order, dependent only on the concentration of titanium trichloride at a fixed concentration of MB. The effect of water and aqueous–alcoholic solvents was studied in the acidic pH range (4–7). It was observed that the quantum yield ( ϕ ) of the reaction increased with increase in polarity of the reaction medium. The quantum yield was high under acidic conditions and decreased with further increase in acidity. The addition of ions and increase in temperature increased the rate and quantum yield of the reaction. The absence of any reaction intermediate was confirmed by spectroscopic investigations. A mechanism for the reaction has been proposed in accordance with the kinetics of the reaction. The activation energy ( E a ) was calculated by the Arrhenius relation. Thermodynamic parameters such as E a , enthalpy change (Δ H ), free energy change (Δ G ), and entropy change (Δ S ) were also evaluated.