Abstract: The invention relates to a process for preparing isocyanates, comprising (a) the reaction of at least one amine with phosgene in the gas phase in a reaction zone and (b) the subsequent cooling of the reaction gases in a cooling zone by means of indirect cooling, the cooling medium which absorbs the heat of the reaction gases being conducted in countercurrent to the product stream at least in the region of the highest temperature in the cooling zone.

Abstract: The invention relates to a process for preparing isocyanates by reacting the corresponding amines with phosgene in the gas phase, if appropriate in the presence of an inert medium, in which the amine and the phosgene are first mixed and converted to the isocyanate in a reactor, by cooling a reaction gas which comprises isocyanate and hydrogen chloride and leaves the reactor in a quench by adding a liquid quench medium to obtain a mixture of reaction gas and quench medium. The amount of quench medium added is such that the temperature of the mixture of reaction gas and quench medium which is established in the quench is above the dew point of the gas present in the quench.

Abstract: The invention relates to a process for preparing isocyanates by reacting the corresponding amines with phosgene in the gas phase, in the presence or absence of an inert medium, which comprises the following steps: (a) vaporization of the amine in a vaporizer, (b) superheating of the amine, (c) mixing of the gaseous amine with the phosgene and introduction into a reaction zone, (d) reaction of amine and phosgene to give isocyanate in the reaction zone, with a reaction mixture comprising isocyanate and hydrogen chloride being formed, (e) cooling of the reaction mixture comprising isocyanate and hydrogen chloride, wherein the vaporizer comprises a vessel in which tubes through which a heating medium flows are comprised, where number and diameter of the tubes are designed so that the tubes have a specific heat transfer area based on the volume through which the amine flows of at least 300 m2/m3.

Abstract: The invention relates to a process for preparing isocyanates by reacting the corresponding amines with phosgene in the gas phase, if appropriate in the presence of at least one inert medium, the phosgene being passed into a reactor (21) through a first inlet and the amine through a second inlet of an ejector (1). The first inlet and the second inlet open into a mixing zone (17) in which the phosgene and the amine are mixed to give a reaction mixture. The mixing zone (17) is followed downstream by a diffuser (19) in which pressure and temperature of the reaction mixture composed of phosgene and amine are increased.

Abstract: The present invention relates to a process for preparing isocyanates.

Abstract: A shell-and-tube reactor is disclosed. Contact tubes are disposed within a cylindrical housing and are secured to tube plates. Gas and liquid phases are received via a feed opening in a lower end cap and discharged via an upper end cap in the housing. A distributor device is disposed in the housing, such that the tube plates serve as a horizontal plate for the distributor device to back up the gas phase and form a gas cushion, and vertical elements extend from the contact tubes. The vertical elements are adapted to conduct the liquid phase, are open in the upstream direction, and project outward in the direction of the feed opening through the gas cushion. The vertical elements further include at least one first opening on the circumference for the gas phase and at least one second opening for the liquid phase.

Abstract: A process for coating internals in a reactor, except for the coating of electrically heatable, at least partly open-cell foams, with a catalytically active material or a precursor thereof, in which an aerosol which contains the catalytically active material or the precursor thereof as a disperse phase is provided and the aerosol is passed through the reactor at a rate in the range from 0.1 to 4 m/s, which is established so that the disperse phase of the aerosol is deposited on the internals in the reactor.

Abstract: The present invention relates to a process for preparing diisocyanates from diamines and phosgene in the gas phase.

Abstract: The present invention relates to a process for preparing isocyanates.

Abstract: The invention relates to a process for recovering acids from product streams of organic syntheses, which comprises the steps a) neutralization of the acid with a base, b) removal of the base by means of adsorption, c) recovery of the acid.

Abstract: The invention provides a process for preparing diphenylmethanediamine, comprising the steps of a) reacting aniline with formaldehyde in the presence of an acid, b) neutralizing the acid with ammonia, c) separating the reaction mixture from step b) into an aqueous phase and an organic phase, d) treating the aqueous phase obtained in step c) with an oxide or hydroxide of an alkaline earth metal, e) separating off the ammonia obtained in step d).

Abstract: The present invention relates to a process for preparing isocyanates in particular apparatuses.

Abstract: The present invention relates to a process for preparing isocyanates.

Abstract: The present invention relates to a process for preparing diisocyanates from diamines and phosgene in the gas phase.

Abstract: The present invention relates to a process for preparing isocyanates and an apparatus suitable for this purpose, and also its use.

Abstract: A shell-and-tube reactor is disclosed. Contact tubes are disposed within a cylindrical housing and are secured to tube plates. Gas and liquid phases are received via a feed opening in a lower end cap and discharged via an upper end cap in the housing. A distributor device for a gas phase/liquid phase mixture is disposed below the lowermost tube plate. The distributor device includes a distributor plate and a predistributor. The distributor plate is arranged horizontally within the housing and includes an active area having through-openings and a downward-extending margin, but does not extend over the entire cross section of the housing. The predistributor includes a second distributor plate disposed between the feed opening and the first distributor plate, wherein the second distributor plate includes a second active area with second through-openings and a second downward-extending margin.

Abstract: Distributor device (1) for a gas phase/liquid phase mixture for an apparatus (2) into whose interior a gas phase and a liquid phase are introduced via at least one feed opening (4), wherein the distributor device (1) comprises a horizontal plate (5) and vertical elements (6) which conduct the liquid phase and are arranged thereon and are open in the upstream direction and project outward in the direction of the feed opening (4) through the gas cushion formed, with at least one opening (10) for the gas phase being provided on the circumference of the elements (6) which conduct the liquid phase in the region of the gas cushion formed and at least one opening (11) for the liquid phase.

Abstract: A reactor for testing catalyst systems which has a plurality of catalyst tubes (2) which are arranged parallel to one another in the interior space of the reactor and whose ends are welded into tube plates and also has caps (3) at each end of the reactor which each bound a cap space (4), with a fluid reaction medium (5) being fed via one cap space (4) into the catalyst tubes (2), flowing through the catalyst tubes (2) and being discharged via the other cap space (4), and is also provided with a heat exchange medium circuit in which the heat exchange medium (6) is fed in at one end of the reactor, flows through the intermediate space between the catalyst tubes (2) and flows out at the other end of the reactor, wherein the catalyst tubes (2) are arranged in two or more catalyst tube regions (7) which are thermally separate from one another, is proposed.

Abstract: The invention relates to a method for producing a uniform flow through an electrolyte space of an electrolysis cell, in which a maximum deviation of less than 1% to 25% from the average flow rate is achieved by suitable design measures.

Abstract: The invention relates to a pump (1) having a pump guide tube (13) for the transport of a heat-exchange medium (6) for a reactor having a bundle of catalyst tubes (2), where the pump (1) has a casing (14) which surrounds the pump guide tube (13), having an aperture (15) in the lower part of the casing (14) via which the heat-exchange medium (6) discharged from the lower region of the reactor by means of the pump (1) flows into the casing (14), flows upward in the region between the inner wall of the casing (14) and the outer wall of the pump guide tube (13), if desired via a heat exchanger (18), flows into the interior of the pump guide tube (13) via an aperture (16) in the upper region of the pump guide tube (13), flows through the pump guide tube (13) from top to bottom and flows via an aperture (17) in the lower region of the pump guide tube (13) into the reactor, into the upper region of the interspace between the catalyst tubes (2).