Total oxidation of naphthalene with high selectivity using a ceria catalyst prepared by a combustion method employing ethylene glycol

During the catalytic combustion of naphthalene, compounds other than CO(2) are often obtained. These products, as polymerized polycyclic aromatic hydrocarbons, oxygenated aromatic compounds and benzene derivate compounds, are usually more toxic than naphthalene. At the present work it is shown a nanocrystalline cerium oxide prepared by a combustion method employing a proper ethylene glycol concentration that exhibits very high activity in the decomposition of naphthalene in the presence of air and, most importantly, a selectivity value towards CO(2) of 100% for any range of conversions and/or temperatures used. In addition, it has been demonstrated that the amount of ethylene glycol employed in the synthesis of the catalyst is determinant to achieve the optimal catalytic performance. The catalytic results have been explained in terms of the amount of cerium oxide defects.

Epoxide ring-opening and Meinwald rearrangement reactions of epoxides catalyzed by mesoporous aluminosilicates

Mesoporous aluminosilicates efficiently catalyze the ring-opening of epoxides to produce beta-alkoxyalcohols in high yields under extremely mild reaction conditions. These materials also catalyze the corresponding Meinwald rearrangement in non-nucleophilic solvents to give aldehydes which can be trapped in situ to provide the corresponding acetals in an efficient tandem process.

Chemically Induced Fast Solid-State Transitions of ω-VOPO 4 in Vanadium Phosphate Catalysts

Vanadium phosphates are important catalysts for the oxidation of alkanes, and commercial catalysts comprise a complex range of V4+ and V5+ phosphates. We used three complementary in situ characterization methodologies-powder x-ray diffraction and laser Raman and electron paramagnetic resonance spectroscopies-to show that the metastable phase omega-VOPO4 is very sensitive to many of the reactants and products of butane oxidation. A rapid transformation from omega-VOPO4 to delta-VOPO4 occurs on exposure to butane at the reaction temperature, and hence the metastable omega-VOPO4 may play a role in the formation of commercial catalysts.

Nanocrystalline cobalt oxide: a catalyst for selective alkane oxidation under ambient conditions

Nanocrystalline cobalt oxide activates propane, yielding propene at room temperature and pressure.

A double-blind, placebo-controlled, parallel dose-response study of amlodipine in stable exertional angina pectoris

A placebo-controlled, double-blind, dose-response study of amlodipine (1.25, 2.5, 5, and 10 mg once daily) was carried out in 136 patients with stable exertional angina pectoris. Improvements in total exercise tolerance, time to onset of angina during exercise, ST-segment deviation at maximum common load, frequency of angina attacks, and nitroglycerin consumption were greater following amlodipine than placebo. The maximum improvement in exercise parameters occurred with the highest dose of amlodipine. All doses produced significant reductions in angina attack frequency and the rate of nitroglycerin consumption. Amlodipine was well tolerated and no patients were withdrawn due to adverse events or laboratory abnormalities.