NOVELTY - Styrene is produced from benzene and ethane by the simultaneous dehydrogenation of ethylbenzene and ethane to give styrene and ethylene respectively.    USE - Styrene is used in the production of thermoplastic polymers such as polystyrenes, acrylonitrile-butadiene-styrene copolymers, styrene-acrylonitrile resins, styrene-butadiene elastomeric copolymers, and in formulations for unsaturated polyester resins.    ADVANTAGE - Styrene of purity greater than 99.5% can be recovered.    DETAILED DESCRIPTION - Production of styrene is effected by:    (1) feeding a stream of benzene and a stream of recycled product containing ethylene to an alkylation unit;    (2) mixing the stream at the outlet of the alkylation unit, which contains ethylbenzene, with a stream of ethane;    (3) feeding this mixture to a dehydrogenation unit containing a catalyst capable of contemporaneously dehydrogenating ethane and ethylbenzene to give ethylene and styrene respectively;    (4) feeding the product from (3) to a separation section to produce a styrene stream and an ethylene stream; and    (5) recycling the ethylene stream to the alkylation unit.    An INDEPENDENT CLAIM is also included for the contemporaneous dehydrogenation of ethane and ethylbenzene to give ethylene and styrene in the presence of a catalytic system.    DESCRIPTION OF DRAWING(S) - The drawing shows the process for the production of styrene.    Alkylation unit (A)    Air cooler (AC)    Separator (C)    Dehydrogenation reactor (D)    (F2)(F3) Filtration units (F1)    (G2) Heat exchangers (G1)    Regeneration unit for the catalyst (R)    Distillation system (S)    Compression unit (T)    Benzene (1)    Ethane (2)    Inert products (3)    Alkylated product (4)    Dehydrogenated product (8)    Light products (ethylene, ethane, methane and hydrogen) (11)    Stream of condensable products (styrene, ethylbenzene and other by-products) (12)    Recycled products (14)    Recycled ethylbenzene (16)    High purity styrene (18)    Effluent gases from the regenerator (19)