Patent ID: 8573519

Claim:
A method for producing nanoscale organic solid particles starting from the corresponding sublimable organic solid as raw material, in the form of particles having an average particle diameter in the range of from 1 μm to 10 mm, which are dispersed in a carrier gas so as to obtain a dispersion, containing the particles of the sublimable organic solid as a disperse phase in the carrier gas as a continuous phase, the solid particles of the dispersion being sublimed in molecularly disperse form by supplying heat at a temperature below the decomposition temperature, so as to obtain a carrier gas flow saturated or unsaturated with the raw material in molecularly disperse form, and the carrier gas flow containing the raw material in molecularly disperse form being delivered to a convergent nozzle whose narrowest cross section is configured so that the carrier gas flow containing the raw material is accelerated in the convergent nozzle to a velocity in the range of from Mach 1 to Mach 3 and is subsequently relaxed as a free jet through an outlet opening from the convergent nozzle into an elongated expansion chamber so as to obtain a supersaturated carrier gas flow from which the product, i.e. the nanoscale organic solid particles, desublimes, the expansion chamber being arranged rotationally symmetrically about the longitudinal axis of the convergent nozzle, in extension of the convergent nozzle, and being closed on all sides except for the outlet opening from the convergent nozzle at one end and a product outlet opening at the other end of the expansion chamber, and having a ratio of length L to diameter D in the range of from 5 to 20, a reflux region being formed between the free jet and the inner wall of the expansion chamber, in which the carrier gas flow is deflected in the opposite direction to the free jet and is sucked in again by the free jet, wherein openings are provided rotationally symmetrically about the midaxis of the expansion chamber in the wall of the expansion chamber which comprises the product outlet opening, through which openings a secondary gas flow is injected comprising a gas carrier and molecules, ions or nanoscale particles contained in molecularly disperse form therein, which are different from the raw material and which have an average particle diameter that is less than the average particle diameter of the product.