Abstract
It was established that in UV irradiation of solutions of TiCl4 in methanol, ethanol, isopropanol, and butanol, alcohol-chloride complexes of titanium(III) are formed. The quantum yields of the formation of coordination compounds of titanium(III) depend on the nature of the alcohol: 0.08 (methanol); 0.13 (ethanol); 0.20 (butanol); 0.22 (isopropanol). As complexes of titanium(III) accumulate in solution, there is a liberation of molecular hydrogen. The quantum yields of the formation of hydrogen, determined in a steady-state process, are correlated with the values of the C-H bond energy at the α-carbon atom of the alcohol and are equal to 2·10−3, 3.4·10−3, 4.3·10−3 and 1·10−2 for solutions in methanol, butanol, ethanol, and isopropanol, respectively. A substantial increase in the quantum yield of the formation of molecular hydrogen was detected when a heterogeneous catalyst (palladium on silica gel) was used, and the possible mechanism of the process of photocatalytic liberation of hydrogen from alcohols with the participation of titanium complexes is discussed.
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Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 3, No. 2, pp. 181–186, March–April, 1987.
The authors would like to thank V. M. Granchak for his participation in the discussion of the results.
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Korzhak, A.V., Kuchmii, S.Y. & Kryukov, A.I. Photocatalytic liberation of hydrogen from C1-C4 alcohols with the participation of titanium complexes. Theor Exp Chem 23, 172–177 (1987). https://doi.org/10.1007/BF00534577
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DOI: https://doi.org/10.1007/BF00534577