The present invention relates to a process for the preparation of porous particles comprising at least one polyimide by reacting (A) at least one polyisocyanate having on average at least two isocyanate groups per molecule and (B) at least one polycarboxylic acid having at least two COOH groups per molecule or anhydride thereof, in the presence of at least one solvent, optionally at least one catalyst and optionally at least one further additive, to cause precipitation of a polyimide in the solvent to form the porous particles, to porous particles, obtained with this process, to parts, bodies, foams and/or material comprising these porous particles, and to the use of the porous particles or of the parts, bodies, foams and/or material as insulation material and in vacuum insulation.