Transition-metal (Ti,V,Cr,Mn,Fe,Co,Cu) containing ordered nanoporous materials: novel heterogeneous catalysts for selective oxidation reactions

Transition-metal (Ti,V,Cr,Mn,Fe,Co,Cu) containing periodic nanoporous catalysts, were synthesized hydrothermally and characterized using various analytical and spectroscopic techniques. The catalytic performance of the different catalysts was systematically evaluated with a detailed study on TiMCM-41. All the catalysts showed promise for the selective oxidation of cycloalkanes, viz., cyclohexane, cyclooctane, and cyclododecane, under mild reaction conditions. Furthermore, these mesoporous molecular sieves were also active for all the chosen reactions even after several recycling and/or washing treatments. Among the various materials under investigation, the catalysts TiMCM-41 and VMCM-41 showed much higher substrate conversion and excellent product selectivity in conjunction with a minimal leaching of the active species. More importantly, the influence of pore size on the catalytic activity of the bulkier substrates such as cyclooctane and cyclododecane is demonstrated.     

Improving the Mechanical Properties and Wear Resistance of a Commercial Pearlitic Rail Steel Using a Two-Step Heat Treatment

Metallurgical and Materials Transactions A - The possibility of improving the mechanical and wear performance of steel rails with conventional compositions, near-eutectoid and without special...