TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: In the step (a), a lignin-comprising material, lignocellulose material or digestion product from a lignocellulose material or lignin comprising stream from the digestion of a lignocellulose material for producing cellulose (pulp), preferably a black liquor, in particular a black liquor from the kraft digestion (sulfate digestion) is provided as biomass starting material. In step (b), subjecting the biomass starting material to a pyrolysis to effect decomposition. The pyrolysis is: not carried out with addition of hydrogen compounds; or carried out with addition of hydrogen (hydrocracking). The pyrolysis is carried out using a black liquor material which under normal conditions (20 degrees C, 1013 mbar) has a liquid content of not more than 70 (preferably 50) wt.%, based on the total weight of the black liquor material. In the step (b), the biomass starting material provided is subjected to a decomposition in the liquid phase. The biomass starting material, preferably a lignin-comprising starting material, is subjected to decomposition in the presence of an aqueous-alkaline, aqueous-acidic or organic decomposition medium. The decomposition is carried out using cellulose depleted fraction from a pulp process, in particular black liquor from the kraft process. In the step (c), the separation into (C1) and (C2) is effected by distillation, extraction, absorption (all preferred) and/or a membrane process. The separation into (C1) and C2 in step (c) comprises: extracting the decomposition product obtained in step (b) to give an aromatics-enriched extract and an aromatics-depleted residue; optionally separating the extract into an extractant enriched and aromatics-depleted fraction and an aromatics-enriched and extractant-depleted fraction; and introducing the aromatics-enriched extract or the aromatics-enriched fraction into step (d). The decomposition product obtained in step (b) or the fraction (C1) isolated in step (c) has predominantly components having a molecular weight of not more than 500 g/mol. The (C2) isolated in step (c) is at least partly used for producing synthesis gas. The reaction in step (d) comprises a hydrodealkylation and/or a steam dealkylation. The temperature in the dealkylation zone is 400-900 (preferably 500-800) degrees C and the absolute pressure is 1-100 (preferably 1-10) bar. The discharge from the dealkylation zone in step (e) is subjected to a separation to give a stream enriched in single-ring aromatics which are unalkylated or have a low degree of alkylation (E1), a stream enriched in aromatics which are not dealkylated or have a low degree of dealkylation (E2) and a stream enriched in by-products (E3) which are more volatile than (E1) and (E2). The separation of the discharge from the dealkylation zone in step (e) comprises an absorption and further comprises: (e1) contacting the discharge from the dealkylation zone with an absorption medium to give an absorbate enriched in aromatic primary products from the dealkylation and a gas stream (E3) depleted in aromatic primary products from the dealkylation; (e2) separating the absorbate into a stream (E1) enriched in single-ring aromatics which are unalkylated or have a low degree of alkylation, a stream (E2) which is enriched in aromatics which are not dealkylated or have a low degree of dealkylation and optionally a stream comprising the absorption medium; (e3) recycling if present, of the stream comprising the absorption medium to step (e1); and (e4) optionally recycling of at least part of the stream (E2) to the dealkylation zone of step (d). The stream (E3) obtained in step (e) is at least partly used for producing synthesis gas. The synthesis gas-comprising stream or a hydrogen enriched stream produced from the synthesis gas is fed into the decomposition in step (b) and/or into the dealkylation in step (d). EXAMPLE - No suitable example given.