Publications

2013
Zackaria Nairoukh, David Avnir, and Jochanan Blum. 2013. “Acid-Catalyzed Hydration of Alkynes in Aqueous Microemulsions.” ChemSusChem 2013, 6, 430 – 432. Publisher's Version Abstract
Terminal aromatic alkynes are converted rapidly into ketones in a regioselective manner by treatment of their microemulsions with 0.33?M mineral acid between 80 and 140?°C. Internal and aliphatic acetylenes are likewise hydrated, but require longer reaction periods. The products are easily isolated from the reaction mixtures by phase separation. Replacement of H2O by D2O leads to the formation of trideuteriomethyl ketones.
Charlie Batarseh, Zackaria Nairoukh, Iryna Volovych, Michael Schwarze, Reinhard Schomäcker, Monzer Fanun, and Jochanan Blum. 2013. “Catalytic Transfer Hydrogenation of Hydrophobic Substrates by Water-insoluble Hydrogen Donors in Aqueous Microemulsions.” J. Mol. Catal. A Chem. 2013, 366, 210 – 214. Publisher's Version Abstract
In the course of our attempts to replace harmful organic solvents used in organic processes by environmentally favored media, we investigated the transfer hydrogenation of various, unsaturated substrates by cyclohexene and similar water-insoluble hydrogen donors. The catalyst in these reactions was Pd(0) in form of nanoparticles, stabilized by hydrophobic silica sol–gel which can be reused at least 4–6 times without significant loss of activity. The process was shown to depend on the electronic nature of the surfactants. Marlipal® 24/70 gave in most experiments the best results. Except for the hydrolysable 1-chloromethylnaphthalene, where chlorine can be substituted by a hydroxyl group, the aqueous medium does not take part in the catalytic process.
Shirel Dahoah, Zackaria Nairoukh, Monzer Fanun, Michael Schwarze, Reinhard Schomäcker, and Jochanan Blum. 2013. “Decarbonylation of Water Insoluble Carboxaldehydes in Aqueous Microemulsions by Some Sol–Gel Entrapped Catalysts.” J. Mol. Catal. A Chem. 2013, 380, 90 – 93. Publisher's Version Abstract
In the course of our attempts to replace harmful solvents in organic processes by environmentally favored media, we investigated the use of aqueous microemulsions for catalytic decarbonylation of different kinds of aldehydes. The aldehydes were solubilized in the microemulsions with the aid of the cationic surfactant, cetyltrimethylammonium bromide. The aldehydes were transferred into CO-free products by sol–gel entrapped catalysts. The best results were obtained in the presence of nanoparticles of Pd(0). The heterogenized catalyst could usually be recycled 7–8 times without loss of catalytic activity. At relatively low temperatures (140°C) the decarbonylation proceeds stepwise. Initially a mixture of saturated and unsaturated products is formed. At 180°C however, fast hydrogenation of the unsaturated compounds takes place. These investigations may be regarded as model studies for the conversion of biomass derived intermediates to fuels and chemicals.