III International Conference

STYRENE PRODUCTION BY CATALYTIC DEHYDROGENATION OFETHYLBENZENE WITH SULFURPP-I-73Novopashina V.M., Kovalenko O.N.Boreskov Institute of Catalysis SB RAS, Novosibirsk, RussiaE-mail: veranov@mail.ruThe influence of temperature, reaction mixture composition and contact time on thestyrene formation by interaction of ethylbenzene with sulfur vapor at the presence acid-basecatalysts has been studied. The optimal conditions of catalytic dehydrogenation ofethylbenzene by sulfur vapor with preferable formation of styrene have been determined.Catalytic dehydrogenation of ethylbenzene is the basic industrial process of styreneproduction – one of the basic monomers for plastic manufacture. In the similar way α-methylstyrene and divinylbenzene are obtained from cumene and diethylbenzene,respectively, which are applied widely as copolymers.Performance of the dehydrogenation process with elemental sulfur as the dehydrogenatingagent has the same advantages, as oxidative dehydrogenation in the presence of oxygen, andallows approximately 40 percents reducing of the heat absorption of reaction and displacingthe thermodynamic equilibrium of reaction towards products. Molecular sulfur is a milderdehydrating agent compared to molecular oxygen; it seems realistic to provide a quantitativearomatic olefins yield through the reaction of alkylaromatic hydrocarbons with sulfur. Thecyclic S 8 molecule is low reactive, its activation needs destruction of the cycle. Sulfurmolecules containing less than eight sulfur atoms are more reactive. Thermal decompositionof S 8 molecules to produce low-molecular S 2 –S 8 species is achieved at temperatures above300 °C [1]. The S 8 ring also can be opened in the presence of catalysts of the acid-base type orthe ones containing transition metal ions, much more reactive surface-linked polysulfidechains being formed [2].Study of the new process of dehydrogenation of ethylbenzene by sulfur vapor at the presenceacid-base catalysts has been fulfilled under following conditions: atmospheric pressure, thetemperature range between 400 and 650 °C, the contact times in the range 0.1 to 1,5 s, theethylbenzene concentration in the reaction mixture 2-50 % vol., ratio S 1 /C 2 H 5 C 6 H 5 – 0.25-0.9.The influence of temperature, reaction mixture composition and contact time on theselectivity for styrene has been studied. It has been found that the reaction of catalyticdehydrogenation of ethylbenzene by sulfur vapor proceeds fast enough at temperatures not137