| CPC C07C 4/22 (2013.01) [B01J 8/24 (2013.01); C08J 11/12 (2013.01); C07C 2601/16 (2017.05); C08J 2325/06 (2013.01); C08J 2423/06 (2013.01); C08J 2423/12 (2013.01); C08J 2455/02 (2013.01); C08J 2467/02 (2013.01)] | 20 Claims |
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1. A process for the production of styrene monomers by depolymerization of a polystyrene-containing polymer composition, comprising the steps of:
a) introducing a polymer composition (A) containing:
10% to 99.5% by weight of a polystyrene (I), based on the total weight of the polymer composition (A); and
II) 0.1% to 89.9% by weight of a polyolefin (II), based on the total weight of the polymer composition (A); and/or
III) 0.1% to 4.9% by weight of an acrylonitrile-based polymer (III), based on the total weight of the polymer composition (A); and/or
IV) 0.1% to 4.9% by weight of a polyester (IV), based on the total weight of the polymer composition (A),
into a reaction zone (R) of a pyrolysis reactor (P);
b) thermally cleaving the polystyrene (I) present in the polymer composition (A) in the reaction zone (R) of the pyrolysis reactor (P) at a temperature of from 400° C. to 1000° C. to obtain a product mixture (G) containing styrene monomers and further components;
c) withdrawing the product mixture (G) obtained in step b) from the reaction zone (R) of the pyrolysis reactor (P);
d) cooling the product mixture (G) withdrawn in step c) to obtain a condensed product mixture (K) containing styrene monomers and further components; and
e) separating the styrene monomers from the further components of the condensed product mixture (K) obtained in step d),
wherein an average residence time (Z) of the polymer composition (A) in the reaction zone (R) of the pyrolysis reactor (P) is from 0.01 s to 10 s.
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