Process for the production of vinyl aromatic monomers which comprises: a)
feeding an aromatic stream and an olefinic stream to an alkylation unit;
b) feeding the reaction product coming from the alkylation section to a
first separation section; c) recovering the mono-alkylated aromatic
hydrocarbon and the heavy bottom product from the first separation
section; d) feeding the mono-alkylated aromatic to a dehydrogenation
section; e) feeding the reaction product coming from the dehydrogenation
section to a second purification/separation section; f) also feeding the
heavy bottom product of step (c) to the second purification/separation
section; g) recovering a stream consisting of the vinyl aromatic monomer
with a purity higher than 99.7 by weight.