Catalytic reduction of benzonitrile derivatives to benzoaldehyde derivatives

Preparation of benzaldehyde derivatives (I) comprises reacting the corresponding benzonitrile compound (IV) with hydrogen in the presence of (a) water, (b) acid or acid salt with a pKa value of 1-6 in an aqueous reference system and (c) a catalyst containing nickel and aluminum. Preparation of benzaldehyde derivatives of formula (I) comprises reacting the corresponding benzonitrile compound of formula (IV) with hydrogen in the presence of (a) water, (b) acid or acid salt with a pKa value of 1-6 in an aqueous reference system and (c) a catalyst containing nickel and aluminum. [Image] R1>, R2>, R4>, R5>H, F, optionally protected formyl, 1-12C alkyl, 1-12C haloalkyl, 1-12C alkoxy, 1-12C haloalkoxy, 4-14C aryl, 5-15C arylalkyl, PO-[(1-8 C)-alkyl]2, PO-[(4-14C)-aryl]2, PO-[(1-8C)-alkyl)(4-14C)-aryl)], tri(1-8C alkyl)siloxyl, A-CO-B', A-E, A-SO2-B', A-SO2R6>, A-SO3W or A-COW; A : absent or 1-8C alkylene; B' : R6>, OR6>, NHR7> or N(R7>)2; R6>1-8C alkyl, 1-8C haloalkyl, 5-15C arylalkyl or 4-14C aryl; R7>1-8C alkyl, 5-15C arylalkyl or 5-14C aryl, or N(R7>)2cyclic amino; W : OH or NH2, and R3>H, F, Cl or Br. NB: E is not defined. Die Erfindung betrifft ein Verfahren zur katalytischen Reduktion von substituierten Benzonitrilen zu substituierten Benzaldehyden in Gegenwart wäßriger Säuren, eines Nickel- und Aluminium- enthaltenden Katalysators und Wasserstoff.