Abstract: A process for the purification of toluenediisocyanate by fractionating a crude distillation feed containing toluenediisocyante, an organic solvent and less than 2% by weight of phosgene in a heat integrated system having an upstream distillation column, an interchanger and a downstream distillation column which are connected in series. The vapor which is recovered from the upstream distillation column is used to reboil the bottoms product of the downstream distillation column or the feed to the downstream distillation column in the interchanger. The crude distillation feed comprising less than 2% by weight of phosgene is fractionated into three product fractions P1-P3 and optionally a fourth fraction P4. P1 is a noncondensible gas stream enriched with phosgene and/or low-boilers. P2 is a solvent-enriched product. P3 is a high boiler enriched bottoms product comprising toluenediisocyanate, and P4 is a toluenediisocyanate enriched stream lean in highboilers and reaction residues.

Abstract: A process for the purification of toluenediisocyanate by fractionating a crude distillation feed containing toluenediisocyante, an organic solvent and less than 2% by weight of phosgene in a heat integrated system having an upstream distillation column, an interchanger and a downstream distillation column which are connected in series. The vapor which is recovered from the upstream distillation column is used to reboil the bottoms product of the downstream distillation column or the feed to the downstream distillation column in the interchanger. The crude distillation feed comprising less than 2% by weight of phosgene is fractionated into three product fractions P1-P3 and optionally a fourth fraction P4. P1 is a noncondensible gas stream enriched with phosgene and/or low-boilers. P2 is a solvent -enriched product. P3 is a high boiler enriched bottoms product comprising toluenediisocyanate, and P4 is a toluenediisocyanate enriched stream lean in highboilers and reaction residues.

Abstract: An improved process is provided for the recovery of a polymer from a solution thereof in a process wherein the polymer solution is contacted with hot water and steam to yield a slurry in water of polymer particles and a vapor stream comprising water vapor and the solvent, the slurry in water of polymer particles is passed to means to grossly separate the polymer particles and the water and the polymer particles are dried, wherein the water contains small particles of polymer and a portion thereof is mixed with the original polymer solution and the remaining portion is passed to the vessel wherein the polymer solution is first contacted with hot water and steam.

Abstract: With a view to improving the heat transfer in exothermic reactions and simplifying the construction of the cooling system of the reactor, in particular a stirrer reactor, vertical boiling tubes which are sealed at the bottom are provided, above which is arranged a condensate collecting and liquid distributing chamber in which a sufficient layer of cooling liquid is constantly maintained by means of a liquid level regulator. Cooling fluid and the vapor produced flow in direct contact with each other as they are carried in counter current through the boiling tubes which have only single walls. The vapor passes through the layer of cooling fluid and is continuously discharged and preferably recovered. The condensate is preferably returned to the cooling system.

Abstract: The present invention is directed to a mixer for mixing at least two free-flowing, reactive or unreactive substances comprising(a) a casing having at least two inlets and at least one outlet,(b) a rotatable shaft extending through the casing,(c) at least one rotor disc attached to the shaft such that the rotor disc is perpendicular to the shaft,(d) at least one stator disc attached to the casing such that the stator disc is parallel to the rotor disc and has an opening such that shaft can pass through the stator disc,(e) optionally at least one running wheel attached to the shaft and containing openings such that when the shaft is rotating, the running wheel provides a pumping effect to the mixture passing through the mixer,(f) at least one inlet through the casing for introducing a first substance axially to the shaft and against the rotor disc and(g) at least one inlet for introducing a second substance against a rotor disc at a point which is radially outward from the introduction of the first substance.

Abstract: The present invention is directed to a process for the production of a mono- and/or polyisocyanate by the phosgenation of a mono- and/or polyamine in a mixer which comprises(a) a casing having at least two inlets and at least one outlet,(b) a rotatable shaft extending through the casing,(c) at least one rotor disc attached to the shaft such that the rotor disc is perpendicular to the shaft,(d) at least one stator disc attached to the casing such that the stator disc is parallel to the rotor disc and has an opening such that the shaft can pass through the stator disc,(e) optionally at least one running wheel attached to the shaft and containing openings such that when the shaft is rotating the running wheel provides a pumping effect to the reaction mixture passing through the mixer,(f) at least one inlet through the casing for introducing a phosgene solution axially to the shaft and against the rotor disc,(g) at least one inlet through the casing for introducing a mono- and/or polyamine amine solution or suspe

Abstract: An amine is separated from an aqueous solution of amine and volatile organic compounds by distillation in a column. The vapors generated during distillation are condensed. The condensed vapors are then passed into a separating device in which the volatile organic compounds are removed. The liquid remaining in the separating device is then fed to the head of the distillation column. Water is removed from the column in a sidestream and diamine is the residue. This process is particularly effective in recovering aromatic diamines from solutions which accumulate during hydrogenation of dinitro aromatic compounds.