Testing catalytic activity of ruthenium(III) acetylacetonate in the presence of trialkylphosphite or trialkylphosphine in hydrogen generation from the hydrolysis of sodium borohydride

Masjedi, Mehdi
Demiralp, Tuelin
Özkar, Saim
Catalytic activity of Ru(acac)(3) in the presence of different phosphorus compounds (P(OMe)(3), P(OPh)(3), PPh3 and dppe) was investigated for the first time in the hydrolysis of NaBH4. Phosphorus compound, usually known as poison in catalysis, is involved in the formation of a species which has higher catalytic activity in comparison with Ru(aCaC)(3) alone. Varying the phosphorus compound affects the catalytic activity and lifetime of the catalyst as well as the kinetics and the activation parameters of the hydrolysis of NaBH4. For all of the phosphorus compounds, the hydrogen generation was found to be zero-order with respect to the substrate concentration and first-order regarding the catalyst concentration. The catalyst system with P(OMe)3 shows the highest catalytic activity and provides the largest total turnover number (TTON = 20,700 over 72 h) in the hydrolysis of NaBH4. The highest activation energy and enthalpy values were obtained for the catalyst with dppe (E-a = 59 +/- 2. Delta H-# = 60 +/- 2 kJ/mol) while the lowest values were found for the catalyst system with PPh3 (E-a = 46 +/- 2, Delta H-# = 43 +/- 1 kJ/mol).


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Metin, Onder; Koçak, Ebru; ÖZKAR, SAİM (Springer Science and Business Media LLC, 2011-08-01)
Hydrogen phosphate (HPO4 2−) or poly(acrylic acid) (PAA) stabilized cobalt(0) nanoclusters were in situ generated from the reduction of cobalt(II) chloride during the catalytic hydrolysis of sodium borohydride (NaBH4) in the presence of stabilizers, HPO4 2− or PAA. Cobalt(0) nanoclusters stabilized by HPO4 2− or PAA were characterized by using UV–Visible spectroscopy, TEM, XPS and FT-IR techniques. They were employed as catalysts in the hydrolysis of NaBH4 to examine the effect of stabilizer type on their c...
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A proline-thiourea host-guest complex has been described as a good catalyst for asymmetric reactions such as aldol and Mannich reactions. High stereoselectivities were obtained under optimal conditions. Thiourea was observed to have an important effect on the reactivity and selectivity, even in an unconventional nonpolar reaction medium and without the need to utilize low temperatures. This proline-thiourea host-guest system has the ability to participate in a hydrogen bonding network.
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Demir, Ayhan Sıtkı; Findik, H; Kose, E (Elsevier BV, 2004-03-08)
A chemoenzymatic synthesis of both enantiomers of the pharmacologically interesting alpha'-acetoxy-alpha-methyl and gamma-hydroxy-alpha-methyl cyclic enones starting from alpha-methyl-beta-methoxy cyclic enones is reported. Manganese(Ill) acetate-mediated acetoxylation followed by the enzyme-mediated hydrolysis of alpha'-acetoxy enone provides acetoxy enones 1a and 2a and hydroxy enones 1b and 2b with high enantiomeric excesses in good yields. The reduction of the acetoxy and hydroxy enones furnished both e...
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Inverse relation between the catalytic activity and catalyst concentration for the ruthenium(0) nanoparticles supported on xonotlite nanowire in hydrogen generation from the hydrolysis of sodium borohydride
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Ruthenium(0) nanoparticles supported on xonotlite nanowire (Ru(0)/X-NW) were prepared by the ion exchange of Rua* ions with Ca2+ ions in the lattice of xonotlite nanowire followed by their reduction with sodium borohydride in aqueous solution at room temperature. Ru(0)/X-NW show high catalytic activity and long life time in hydrogen generation from the hydrolysis of sodium borohydride with a turnover frequency value up to 305 min(-1) and a total turnover number of 63,100 mol H-2/mol Ru in hydrogen generatio...
Citation Formats
M. Masjedi, T. Demiralp, and S. Özkar, “Testing catalytic activity of ruthenium(III) acetylacetonate in the presence of trialkylphosphite or trialkylphosphine in hydrogen generation from the hydrolysis of sodium borohydride,” JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL, pp. 59–63, 2009, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/62799.