title: Ultrasound-assisted selective hydrogenation of C-5 acetylene alcohols with Lindlar catalysts.
abstract: The selective hydrogenation of 2-methyl-3-butyn-2-ol (MBY) was performed in the presence of Lindlar catalyst, comparing conventional stirring with sonication at different frequencies of 40, 380 and 850 kHz. Under conventional stirring, the reaction rates were limited by intrinsic kinetics, while in the case of sonication, the reaction rates were 50-90% slower. However, the apparent reaction rates were found to be significantly frequency dependent with the highest rate observed at 40 kHz. The original and the recovered catalysts after the hydrogenation reaction were compared using bulk elemental analysis, powder X-ray diffraction and scanning and transmission electron microscopy coupled with energy-dispersive X-ray analysis. The studies showed that sonication led to the frequency-dependent fracturing of polycrystalline support particles with the highest impact caused by 40 kHz sonication, while monocrystals were undamaged. In contrast, the leaching of Pd/Pb particles did not depend on the frequency, which suggests that sonication removed only loosely-bound catalyst particles.
authors: Sonochemistry Centre, Department of Health and Life Sciences, Coventry University, James Starley Building, Priory Street, Coventry CV1 5FB, United Kingdom.
authors: B
authors: B
authors: Tripathi
authors: Sonochemistry Centre, Department of Health and Life Sciences, Coventry University, James Starley Building, Priory Street, Coventry CV1 5FB, United Kingdom.
authors: L
authors: L
authors: Paniwnyk
authors: Catalysis and Reactor Engineering Research Group, Department of Chemistry and School of Biological Biomedical and Environmental Sciences, University of Hull, Cottingham Road, Hull HU6 7RX, United Kingdom.
authors: N
authors: N
authors: Cherkasov
authors: Catalysis and Reactor Engineering Research Group, Department of Chemistry and School of Biological Biomedical and Environmental Sciences, University of Hull, Cottingham Road, Hull HU6 7RX, United Kingdom. Electronic address: a.o.ibhadon@hull.ac.uk.
authors: A O
authors: AO
authors: Ibhadon
authors: Departament de Química Física i Institut Universitari d'Electroquímica, Universitat d'Alacant, Ap. 99, E-03080 Alicante, Spain.
authors: T
authors: T
authors: Lana-Villarreal
authors: Departament de Química Física i Institut Universitari d'Electroquímica, Universitat d'Alacant, Ap. 99, E-03080 Alicante, Spain.
authors: R
authors: R
authors: Gómez
keywords: Alkynol; Lindlar catalyst; Palladium; Semihydrogenation; Ultrasound