189 Comparative Study of Iron Porphyrin Supported on Mesoporous Al-MCM-41 and Poly(methacrylic acid) (PMAA) : Characterization and Their Catalytic Activities Helda Hamid 1 , Salasiah Endud 1 , Hadi Nur 1 and Zainab Ramli 1 1 Ibnu Sina Institute for Fundamental Science Studies, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia. Corresponding author email address : salasiah@kimia.fs.utm.my Abstract Mesoporous molecular sieve Al-MCM-41 with Si/Al=20 and poly(methacrylic acid) (PMAA) were used as supports for the immobilization of bulky iron (III)-5,10,15,20- tetra-(4-pyridyl) porphyrin, (Fe-TPyP). Metalloporphyrin of Fe(III) was encapsulated inside the mesopores of crystalline samples of Al-MCM-41 by a process of sequential synthesis of Fe-TPyP by treatment of FeCl3 with 5,10,15,20- tetra-(4-pyridyl) porphyrin (TPyP), followed by encapsulation of Fe-TPyP. Fe-TPyP complexes were also successfully encapsulated into the pore of PMAA by polymerizing a monomer (MAA) with a cross-linker around the Fe-TPyP complexes. The materials obtained were identified using, XRD, DR-UV/vis and FT-IR spectroscopies. The powder XRD data confirmed that the crystallinity of mesoporous Al-MCM-41 was maintained after encapsulation process. With mesoporous molecular sieve (Al- MCM-41) and the polymer (PMAA) as supports, the encapsulated iron-porphyrin systems have demonstrated excellent activity for the one-step oxidation of benzene to phenol under mild reaction conditions. Keywords : Encapsulation; Iron-porphyrin; Al-MCM-41; PMAA. Introduction Selective oxidation of hydrocarbons under mild conditions is of academic interest and industrial importance [1]. In recent years, as a result of increasing environmental constraints, “clean” oxidants such as dioxygen (or air), hydrogen peroxide, and alkyl hydroperoxides, which are inexpensive, is becoming more important both in industry and academia, and chemical processes based on cleaner technologies are expected to increase significantly in the next few years. In this research, the only focus was on the catalytic heterogeneous oxidation. A well-known monooxygenase, iron porphyrin-based cytochrome P-450, has been the subject of intensive study [2] largely because of their ability to catalyze a wide variety of oxidation transformations, e.g. alkenes epoxidation, alkanes hydroxylation, etc. with molecular oxygen. In the last two decades, therefore, increasing attention in catalytic oxidation has been focused on the use of biomimetic systems based on Fe(II), Ru(II) and Mn(II) [3-5]. Fig. 1 shows a unique metalloporphyrin structure containing alternately perpendicular porphyrin molecules that give rise to an unprecedented two-dimensional paddle-wheel-like pattern (4 4 topology). Synthetic metalloporphyrins are widely used as homogeneous catalysts for hydrocarbon oxidation, as well as model for cytochrome P-450 [6,7]. Metalloporphyrin complexes of iron [8] are known to be active catalysts for alkenes epoxidation. There are, however, several disadvantages in using metalloporphyrins as catalysts in homogeneous oxidation processes. The difficulty in separating the catalysts from the product substantially increases the cost of using homogeneous catalysis in commercial processes. Heterogeneous catalysts, on the contrary, can be easily separated from the reaction products simply by filtration. Yet most heterogeneous catalysts are less selective in complex reactions. Therefore, it is highly desirable to develop new classes of catalysts which possess both the high selectivity of homogeneous catalysts and the convenience of heterogeneous catalysts.