Turkish J. Eng. Env. Sci. 36 (2012) , 59 – 71. c  T ¨ UB ˙ ITAK doi:10.3906/muh-1103-14 Comparison between the performances of a fluidized-bed reactor and a fixed-bed reactor for the oxidation of benzene to maleic anhydride Canan URAZ ∗ , S¨ uheyda ATALAY Department of Chemical Engineering, Faculty of Engineering, Ege University, 35100 Bornova, ˙ Izmir-TURKEY e-mail: canan.uraz@ege.edu.tr Received: 28.03.2011 Abstract The selective oxidation of benzene to maleic anhydride (MAN) was studied to compare the performances of fluidized-bed and fixed-bed reactors. The gas-phase catalytic oxidation of benzene was carried out in laboratory-scale fluidized-bed and fixed-bed reactors with a vanadium pentoxide catalyst supported by silica gel. The influences of parameters such as temperature, space time, and air-to-benzene molar ratio on the reaction selectivity were investigated at normal atmospheric pressure. Similar operating conditions were provided in the experiments carried out in both reactors. Because of the limitations of the experimental sets-up and the recommended operating conditions given in the literature, some differences could be seen between the reactors. It was observed that the conversion of benzene to MAN increased with increasing temperature in both reactors. It was further found that both the conversion of benzene to MAN (x 1 ) and the total conversion of benzene (x T ) also increased with increasing air-to-benzene molar ratios. This study demonstrates the availability of the 2 reactors for the oxidation reaction of benzene to MAN. Key Words: Gas-phase oxidation, benzene, maleic anhydride, fixed-bed reactor, fluidized-bed reactor 1. Introduction The oxidation of organic compounds such as benzene in the vapor phase is an industrially important reaction since the main product, maleic anhydride (MAN), and the side product, phthalic anhydride, are very valuable intermediates. MAN is also referred to as 2-5 furandione, cis-butenedionic anhydride, toxilic anhydride, and maleic acid anhydride. This multifunctional chemical intermediate finds applications in almost all fields of in- dustrial chemistry. The principal use of MAN is in the manufacture of alkyd and unsaturated polyester resins, surface coatings, plasticizers, lubricating oil additives, agricultural chemicals, textile chemicals, paper reinforce- ment, food additives, and pharmaceuticals. Furthermore, due to its double bond and anhydride function, MAN is a versatile intermediate for the production of copolymers of MAN, such as, for example, ethylene glycol and vinyl monomer. Recently, potential new uses of MAN have been found in its conversion to 1,4-butanediol and ∗ Corresponding author 59