Recently, Fe3O4 magnetic nanoparticles as an immobilization matrix have been increasingly applied to immobilizing proteins, enzymes,and other bioactive agents in analytical biochemistry, medicine, and biotechnology [1]. In addition to their applications in the immobilization of biomolecules, Fe3O4 magnetic nanoparticles have found many other applications such as bioseparation, drug delivery, biosensors, DNA detection [2], and molecular interactions in live cells [3]. Pure Fe3O4 magnetic nanoparticles are likely to form a large aggregation, have fewer activating group and be easily oxidized or dissolved in an acid medium. Therefore, a suitable coating on the surface of the pure magnetic nanoparticles is essential to avoid such limitations, mean while improves the physicochemical properties of the nanoparticles and maintains the colloidal suspension stability within the biological environment. Encapsulated-Silica bearing pyridinium dichromate groupe is an important shell-forming material owning to its high chemical and thermal stabilities, large surfaceareas and good compatibilities with other materials [4]. For example, this coating layer, Change pyridinium dichromate to a mild and recycleable agent for alcohol Oxidation [5]. To determine the efficiency of the catalytic and optimize the conditions an amount of synthesized catalyst is reacted with various alcohols such as benzyl alcohol ̦ meta nitro benzyl alcohol ̦ meta bromo benzyl alcohol and meta methoxy benzyl alchohol and the Conversion of alcohol to aldehyde is measured by Gas Chromatography (GC) . The resulting catalyst was extensively characterized by XRD, SEM (scanning electronic microscopy), ICP̦ and FT-IR spectroscopy. The presence of C=N band in the IR spectrum and the size of nanoparticles in SEM indicating the formation of the new compound