Method for separating volatile substances from material mixtures and device for producing polyarylene sulfides

An apparatus for producing polyarylene sulfides including at least one repeat unit in accordance with the general formula I

• A-S Formula I,
• (where A represents a bivalent aromatic radical) produced by condensation polymerization of a di-iodized aromatic compound in accordance with the general formula II
• I-A-I Formula II
• using a sulfidation agent, comprising
• a) a precondensation stage comprising an agitating tub or a cascade of agitating tubs composed of a plurality of agitating tubs connected one after the other, wherein the agitating tub and/or the first agitating tub of the cascade of agitating tubs has at least one input possibility for the reactants, and has an outlet for the prepolymer, and downstream of the agitating tub or the cascade of agitating tubs further comprising;
• b) a condensation polymerization step comprising at least one condensation polymerization reactor or a cascade of a plurality of condensation polymerization reactors connected one after the other, wherein the condensation polymerization reactor and/or the first condensation polymerization reactor of the cascade of a plurality of condensation polymerization reactors has an input possibility for the prepolymers obtained from the first step and has a output possibility for the polycondensate,
• wherein the precondensation stage is connected to the condensation polymerization step via a product line,
• characterized in that
• the agitating tub or at least one agitating tub of the cascade of agitating tubs has at least one drainage possibility for gaseous side products and/or non-reacted reactants, in particular iodine and/or the compound having the general formula II;
• and
• the condensation polymerization reactor or at least one condensation polymerization reactor of the cascade of condensation polymerization reactors connected one after the other has at least one drainage possibility for gaseous side products and/or non-reacted reactants, in particular iodine and/or the compound of the general formula II.

A method for producing a polyarylene sulfide including at least one repeat unit of the following general formula I, the method comprising:

• performing a condensation of a di-iodized aromatic compound of the following general formula II using a sulfidation agent,
• wherein a material mixture comprising iodine and/or the at least one di-iodized aromatic compound of the general formula II is separated during the condensation step by a method, characterized in that
• a) a first part of the material mixture is separated at a pressure which is equal to or larger than the pressure which is present at the triple point of iodine;
• and
• b) a second part of the material mixture is separated at a pressure which is smaller than the pressure which is present at the triple point of iodine;
• wherein in both steps a) and b), the material mixture respectively has temperatures at which at least iodine is present in a gaseous state at the said pressures:
• A-S Formula I
• I-A-I Formula II
• In the Formulae I and II, A represents a bivalent aromatic radical.