Abstract:
The invention relates to a multi-stage method for the continuous production of organic, distillable polyisocyanates, preferably diisocyanates, especially preferably aliphatic or cycloaliphatic diisocyanates, by reacting the corresponding organic polyamines with carbonic acid derivatives and alcohol in low-molecular monomer polyurethanes and to the thermal splitting of the latter. During said method, the polyisocyanates produced and unusable residues are separated at specific reaction stages and reusable secondary and intermediate products are recirculated to the initial stages.
Abstract:
The invention relates to a method for mixing a liquid in a container or a mixture of a liquid and a fine-particle solid. According to said method, the same liquid or the same mixture is fed to the container in the form of a propelled stream by means of a jet that has a propelling nozzle and a pulse exchange chamber. The suction region between the propelling nozzle and the pulse exchange chamber is provided with sheathing, which has a suction opening lying beneath the central stream that leads from the propelling nozzle into the pulse exchange chamber.
Abstract:
The invention relates to a device of the loop-Venturi reactor type for the continuous reaction of liquids with gases, in particular for hydrogenation, oxidation or acetylation, e.g. for the production of diaminotoluene by the hydrogenation of dinitrotoluol. The invention also relates to a method for the continuous reaction of liquid reactants with gaseous reactants in the device. The coolant surrounds the tubes of the heat exchanger of the device according to the invention, whereas the reaction takes place in the tubes.
Abstract:
The invention relates to a method and a device for mixing a liquid in a substantially sealed container or a mixture of a liquid and a fine-particle solid, said liquid or mixture only partially filling the internal volume of the container that can be occupied by a fluidic phase and the remaining available internal volume of the container being filled by a gaseous phase. According to the invention, the essentially same liquid or mixture is fed to the container in the form of a propelled stream of a suction device that is situated in the liquid or mixture in the container. In its simplest form, the method according to the invention is implemented by means of an ejector (i.e. according to water jet pump principles) embodied as the suction device. The propelled stream is pumped through a propelling nozzle, which is fitted into the ejector in such a way that gas is sucked from the gaseous phase during the passage of the stream through the nozzle, e.g. by means of a riser tube that projects into the gaseous phase of the container, and is released in the form of dispersed gas bubbles, together with the propelled stream, into the liquid content of the storage container.
Abstract:
The continuous or semi-continuous method of brightening organic polyisocyanates with ozone-containing gas, wherein treatment of the organic polyisocyanate is done using an ozone-containing gas that further comprises at least one other inert and/or reactive gas, can be carried out according to the invention in a stirred vessel with a connected storage tank in a sieve-plate column or in a packed column.
Abstract:
The invention relates to a method for the production of amines by hydrogenating the corresponding nitroaromates in a vertical reactor whose length is greater than its diameter. Said reactor has a jet nozzle directed downward and arranged in the top area of the reactor. The reaction mixture and optionally part of the educts are fed through said jet nozzle. The reactor also comprises an outlet at any given location of the reactor through which the reaction mixture is once again fed into an external circuit by means of a conveying element of the jet nozzle and the flow is reversed in the bottom area of the reactor. The invention is characterized in that part of the educts used hydrogen and/or nitroaromates are proportioned into the liquid phase of the reactor in such a way that said educts rise upward in the liquid phase.
Abstract:
The invention relates to a method for hydrogenating liquid organic compounds, in particular for hydrogenating nitro compounds to obtain amines. Said method is characterised in that the hydrogen that is present in the reactor contains constituent parts of at least one gas that is inert during the hydrogenation reaction.