Abstract: The invention relates to a method for recovering monomer diisocyanates, which are solid at room temperature, from a distillation residue, said method comprising the following steps: (i) preparing at least one residue which contains diisocyanates, which are solid at room temperature, and (ii) separating the residue in at least one kneader-dryer, paddle-dryer and/or roller-dryer in the presence of less than 2 wt % bitumen, based on the mass of the residue prepared in step (i), into a gaseous portion, containing monomer diisocyanate that is solid at room temperature, and a brittle residue depleted of diisocyanate, which is solid at room temperature.

Abstract: One or more fluid streams are uniformly divided into two or more partial fluid streams in chemical apparatuses in a manner such that there is a reduced tendency to form deposits. Division of such stream(s) is achieved by using a distributor device that includes at least one plate having two or more openings which openings are rounded or chamfered on at least one side.

Abstract: The invention relates to a method for producing organic diisocyanates by reacting the corresponding diamines with phosgene in inert solvents. High-melting diamines from the series of 1,5-naphthalenediamine, tetralindiamine, 1,4-phenylenediamine, durenediamine, and o-tolidinediamine are used as diamines. According to the invention, a suspension of the diamines in inert solvents is produced, wherein dynamic mixing units, selected from dispersion disks and rotor-stator systems, are used, and the obtained suspension is phosgenated.

Abstract: The invention relates to a method for producing organic diisocyanates by reacting the corresponding diamines with phosgene in inert solvents. High-melting diamines from the series of 1,5-naphthalenediamine, tetralindiamine, 1,4-phenylenediamine, durenediamine, and o-tolidinediamine are used as diamines. According to the invention, a suspension of the diamines in inert solvents is produced, wherein dynamic mixing units, selected from dispersion disks and rotor-stator systems, are used, and the obtained suspension is phosgenated.

Abstract: One or more fluid streams are uniformly divided into two or more partial fluid streams in chemical apparatuses in a manner such that there is a reduced tendency to form deposits. Division of such stream(s) is achieved by using a distributor device that includes at least one plate having two or more openings which openings are rounded or chamfered on at least one side.

Abstract: Coal tar oil is separated quantitatively into neutral oil, phenols and bases by a two stage extraction with overcritical gases. Carbon dioxide is employed as an overcritical extraction agent, and propane or butane are preferably added as entrainers. The neutral oil is obtained in the first stage. Tar bases can be employed as an additional entrainer for improving the selectivity. The bases are extracted in the second stage. The method is associated with the advantage that it saves energy and that no byproducts are generated.