INTEGRATED METHODS FOR PRODUCTION OF P-XYLOL Russian patent published in 2023 - IPC C07C15/08 C07C7/10 C07C5/27 C07C7/08 

FIELD: chemistry.

SUBSTANCE: invention relates to three options of a method for the production of p-xylol. According to one of options, the method includes stages, at which: in a xylol column, a flow of aromatic hydrocarbons C₈ and a flow of hydrocarbons C₉⁺ are separated from at least part of an ethylbenzene-containing supplied flow; in a xylol separation zone, a p-xylol-enriched product is separated from at least part of the flow of aromatic hydrocarbons C₈ to obtain a p-xylol-depleted waste flow; in an isomerization zone, isomerization of at least part of the p-xylol-depleted waste flow is carried out to obtain xylol-equilibrium isomerizate. At least part of xylol-equilibrium isomerizate is recycled into the xylol column. In an ethylbenzene (hereinafter – EB) separation module, an ethylbenzene-enriched product is separated from (i) part of the ethylbenzene-containing supplied flow to obtain an ethylbenzene-depleted supplied flow, and at least part of the ethylbenzene-depleted supplied flow is connected to all or part of the flow of aromatic hydrocarbons C₈; (ii) part of the flow of aromatic hydrocarbons C₈ to obtain an ethylbenzene-depleted flow of aromatic hydrocarbons C₈, and at least part of the ethylbenzene-depleted flow of aromatic hydrocarbons C₈ is connected to part of the flow of aromatic hydrocarbons C₈, conducted via a bypass outside EB separation module; (iii) part of the p-xylol-depleted waste flow to obtain an ethylbenzene and p-xylol-depleted waste flow, and at least part of the ethylbenzene and p-xylol-depleted waste flow is connected to part of the p-xylol-depleted waste flow, conducted via a bypass outside EB separation module; (iv) part of xylol-equilibrium isomerizate to obtain ethylbenzene-depleted xylol-equilibrium isomerizate, and at least part of ethylbenzene-depleted xylol-equilibrium isomerizate is connected to part of xylol-equilibrium isomerizate, conducted via a bypass outside EB separation module, or (v) combination thereof. In this case, EB separation module contains extractive distillation, wherein extractants with a carbocyclic (for example, aromatic) or heterocyclic ring structure are used, substituted in ring positions, where substitution is possible (i) with at least one NR^aR^b radical (i.e., substitute -NR^aR^b), wherein R^a and R^b are independently selected from a group consisting of an oxygen radical, a hydrogen radical, and a hydrocarbyl radical including from about 1 to about 20 carbon atoms, and (ii) at least two halogen radicals (i.e., halogen substitutes formed of their respective halogen atoms).

EFFECT: present invention allows for efficient extraction of ethylbenzene and other components boiling at a temperature close to the boiling point of xylene isomers.

18 cl, 5 dwg, 1 ex