Process for preparing at least one low molecular weight aromatic material of value from a lignin-comprising starting material

The process according to either of the preceding claims, wherein a lignocellulose material from wood and/or plant fibers is used for providing the lignin-comprising starting material in step a).

The process according to any of the preceding claims, wherein a lignin-comprising stream from the digestion of a lignocellulose material for producing cellulose (pulp) is used for providing the lignin-comprising starting material in step a).

The process according to any of the preceding claims, wherein the pyrolysis gas stream obtained in step b) comprises substituted aromatics and/or polycyclic aromatics.

The process according to any of the preceding claims, wherein essentially none of the components comprised in the pyrolysis gas stream obtained in step b) are condensed out from this stream before it enters the dealkylation zone.

The process according to any of the preceding claims, wherein the temperature of the pyrolysis gas stream after leaving the pyrolysis zone and before entering the dealkylation zone is never more than 200° C. below, particularly preferably never more than 100° C. below, the exit temperature from the pyrolysis zone.

The process according to any of the preceding claims, wherein the reaction in step c) comprises a hydrodealkylation or a steam dealkylation or a mixed form thereof.

The process according to any of the preceding claims, wherein the temperature in the dealkylation zone is in the range from 400 to 900° C., preferably from 500 to 800° C.

The process according to any of the preceding claims, wherein the absolute pressure in the dealkylation zone is in the range from 1 to 100 bar, particularly preferably from 1 to 20 bar, in particular from 1 to 10 bar.

The process according to any of the preceding claims, wherein the discharge from the dealkylation zone is subjected in step d) to a separation to give the following three streams:

• D1) a stream enriched in single-ring aromatics which are unalkylated or have a low degree of alkylation,
• D2) a stream enriched in aromatics which are not dealkylated or have a low degree of dealkylation,
• D3) a stream enriched in by-products which are more volatile than D1) and D2).

The process according to any of the preceding claims, wherein the separation of the discharge from the dealkylation zone in step d) comprises an absorption.