Abstract: The process for the preparation of an aldehyde of formula R--CHO in which R is an alkyl group of C.sub.1 -C.sub.7 comprises according to the invention the reaction on an alkyl formate of formula H--COOR in which R has the meaning given above, of a gas constituted mainly by CO, in the presence of(a) a catalyst based on a metal chosen from among Rh, Ru, Ir, mixtures of them or a mixture of Rh and/or Ru and/or Ir with Co, Ni or Fe,(b) a promoter chosen from among iodides and mixtures of covalent compounds of iodine and a phosphine or a tertiary amine,(c) a solvent consisting of a cyclic N-alkyl amide.

Abstract: The mould comprises a copper mould at least partly surrounded by a cooling box in which a cooling fluid flows. The cooling box comprises a first chamber defined by the copper wall of the mould and by a parallel front wall of the box. This front wall includes magnetic poles which are part of an electromagnetic induction stirring device for the metal cast in the mould. The first chamber is connected to a first cooling circuit. The box also has a second chamber in which the coils and cores of the electromagnetic induction stirring device are disposed.