A simple and mild catalytic coupling reaction of propargyl halides with organotitanium reagents is reported. The reaction of propargyl bromide with organo-titanium reagents mediated by NiCl2 (2 mol%) and PCy3 (4 mol%) in CH2Cl2 afforded coupling product allenes in good to excellent yields (up to 95%) at room temperature. However, NiCl2(PPh3)2 was the best catalyst for substituted propargyl hali...

Understanding the kinetics of olefin polymerization with Ziegler-Natta and related catalysts means identifying the main kinetic parameters such as k(p) and concentration of active sites. The high-pressure quenched-flow technique could be an absolute method for counting active sites and for activation studies of molecular catalysts. A kinetic study of metallocene catalysts and a phenoxy-imine ti...

The results of a study of the photocatalytic oxidation of uichloroethylene (TCE) in air using titanium dioxide as the catalyst are reported. Dichloroacetyl chloride is found to be an intermediate in the oxidation sequence and carbon monoxide, phosgene, carbon dioxide, hydrogen chloride, and chlorine are found in the product mixture. The yields of each, except chlorine, have been determined usin...

To improve the contact between platinum catalyst and titanium substrate, a layer of TiO 2 nanotube arrays has been synthesized before depositing Pt nanoflowers by pulse electrodeposition. Dramatic improvements in electrocatalytic activity (3×) and stability (60×) for methanol oxidation were found, suggesting promising applications in direct methanol fuel cells. The 3× and 60× improvements persi...

Supported olefin polymerization catalysts can prevent reactor-fouling problems and produce uniform polymer particles. Constrained geometry complexes (CGCs) have less sterically hindered active sites than bis-cyclopentadienyl metallocene catalysts. In the literature, micrometer-sized silica particles were used for supporting CGC catalysts, which might have strong mass transfer limitations. This ...

PURPOSE To determine the nature and the origin of metallic foreign particles appearing on the iris after phacoemulsification surgery. SETTING P.D. Hinduja Hospital and Medical Research Centre, Mumbai, Maharashtra, India. DESIGN Case series. METHODS Metallic foreign particles were observed on the iris surface and the pupillary border on the first postoperative visit after phacoemulsificati...