OXIDATIVE DEHYDROGENATION OF ETHYLBENZENE TO STYRENE ON ACTIVATED CARBONS DERIVED FROM A NATIVE WOOD AS CATALYST

摘要

Activated carbons were developed by phosphoric acid activation of a native wood (Pro-sopis ruscifolia) under a self-generated atmosphere or flowing air. Their potentiality as catalyst for oxidative dehydrogenation of ethylbenzene to styrene was examined at pre-established operating conditions. The carbons developed in the self-generated atmosphere showed specific surface area of 2281 m~2/g and total pore volume of 1.7 cm~3/g, whereas values of 1638 m~2/g and 1.3 cm~3/g, respectively, characterized those obtained in air. A commercial activated carbon (1200 m~2/g and 0.7 cm~3/g) was also used for comparison. Both wood-derived carbons resulted potentially suitable as catalyst for ethylbenzene oxidative dehydrogenation. Nevertheless, those developed in the self-generated atmosphere showed a better catalytic performance than the carbons obtained in air and the commercial sample. The behaviour could be due to its lower microporosity compared with the commercial sample, and to the formation of oxidative condensation products during the oxidative dehydrogenation of ethylbenzene with greater content of carbonyl groups than for the sample activated under flowing air. Chemical and textural characterization of the used carbons conclusively evidenced the presence of oxidative condensation products pointing to formation of new active surfaces.