The present invention comprising the steps of: (a) a mixture of a liquid amine-containing reactant stream (1) and the liquid phosgene-containing reactant stream (2) to obtain a reaction mixture; (B) reacting the reaction mixture in the residence time reactor (R) to obtain a reaction mixture (3); (C) reaction by reacting a reaction mixture (3) in a column (K1) to obtain a head stream (4) and a bottom stream (5), the method comprising: feeding the bottom stream (5) in the phosgene / hydrogen chloride stripping column (K2) .; (D) the bottom stream containing the isocyanate and the solvent in the phosgene / hydrogen chloride stripping column (K2) and through the head stream (6) separated by a phosgene and hydrogen chloride by distillation, the phosgene / hydrogen chloride stripping column (K2) of 7 in the obtaining step, and the method steps from the bottom stream (7); (E) separating the solvent by distillation in step, and a method to obtain a marketable product isocyanate; (F) separation column (K3) by thermal fractionation of steam from the phosgene / hydrogen chloride stripping column (K2) in the overhead, hydrogen chloride-containing vapor stream (13), and phosgene, and a bottom stream which is recycled to the containing and method steps a) and the solvent 14 heads in a production process of isocyanates by the reaction of the amine with the phosgene in the carrying the method steps of a step in a liquid state, the method step (f) the phosgene / hydrogen chloride stripping column (K2), the column fractionation in obtaining a compared to pressure it relates to a process for producing an isocyanate, characterized in that for performing the head pressure in the high-separation column (K3).