Abstract: Aromatic diisocyanates are produced by reacting in the gas phase the corresponding primary aromatic diamine with phosgene. The phosgene and the primary aromatic diamine are reacted within a mean residence time of from 0.05 to 15 seconds. The aromatic diamine used contains less than 0.05 mole % overall of aliphatic amine containing no keto groups, per mole of primary amino groups.

Abstract: An isocyanate is produced by reacting a primary amine with phosgene in the gas phase above the boiling point of the amine over an average contact time of 0.05 to 15 seconds under adiabatic conditions.

Abstract: The invention provides an improved process for preparing diamines and polyamines from the diphenylmethane series by reacting aniline and formaldehyde in the presence of an acid catalyst, the improvement involving the aniline containing less than about 3 wt. % of diamines and polyamines from the diphenylmethane series, based on the weight of the aniline.

Abstract: The present invention relates to a process for the preparation of toluenediamine, in which dinitrotoluene is reacted with hydrogen in the presence of a catalyst. The dinitrotoluene required by this process has a content of carbon dioxide, in either physically dissolved or chemically bonded form, of not more than 0.175 mol %, based on the molar amount of the dinitrotoluene.

Abstract: Dinitrotoluene is produced by nitration of toluene with nitrating acid (mixture of nitric acid and sulfuric acid) in which, in a first stage, the toluene is converted to mononitrotoluene (MNT) and then the mononitrotoluene is converted in a second stage to dinitrotoluene (DNT). Control of the weight ratio of the aqueous to organic phases, dispersion of the organic phase in the aqueous phase and use of less than 2.06 moles of nitric acid per mole of toluene are key features of this process.

Abstract: Isocyanates are produced by reaction of primary amines with phosgene in the gas phase. In this process, the reaction is terminated by guiding the reaction mixture from the reaction chamber through a cooling stretch into which liquids are injected. Direct cooling takes place in the cooling stretch in one stage in two or more cooling zones connected in series.

Abstract: The present invention relates to a process for the preparation of toluenediamine, in which dinitrotoluene is reacted with hydrogen in the presence of a catalyst. The dinitrotoluene required by this process has a content of carbon dioxide, in either physically dissolved or chemically bonded form, of not more than 0.175 mol %, based on the molar amount of the dinitrotoluene.

Abstract: An isocyanate is produced by reacting a primary amine with phosgene in the gas phase above the boiling point of the amine over an average contact time of 0.05 to 15 seconds under adiabatic conditions.

Abstract: A method and a device are disclosed for the secure operation of a switching device including at least two main contacts which can be switched on and off and which includes respectively, contact pieces and a displaceable contact bridge, and at least one control magnet which includes a displaceable anchor. The anchor acts upon the contact bridge when it is switched on and off such that the corresponding main contact is opened or closed. At least one embodiment of the inventive method includes the following steps: a) release device for a force element remains in a first state in order to interrupt the main contact as long as the main contacts are closed when switched on and open when switched off, and b) the release device are transferred into a second state if at least the main contact is welded after switching off.

Abstract: A method and a device are disclosed for the secure operation of a switching device including at least one main contact which can be switched on and off and which includes contact pieces and a displaceable contact bridge, and at least one control magnet which includes a displaceable anchor. The anchor and the contact bridge are actively connected to each other such that the corresponding main contact can be opened or closed when switched on and off. In at least one embodiment, the method includes the following: a) the path difference, which returns the anchor after switching on and off, is recognised, b) devices which are used to open welded main contacts are released by a release device when the recognised path difference exceeds a predetermined value and a specific time duration of time has run out after switching off.

Abstract: A method and a device are disclosed for the secure operation of a switching device including at least two main contacts which can be switched on and off and which include contact pieces and a displaceable contact bridge, and at least one control magnet which includes a displaceable anchor. The anchor acts upon the contact bridge when switched on and off such that the corresponding main contact is opened or closed. A switching contact, which has an on and off state corresponding to the closing and opening position of the anchor, is provided. In at least one embodiment, the method includes the following steps: a) an electric control signal which is used to release contact breaking device is produced when the control magnets are switched on and off.

Abstract: Dinitrotoluene is produced by nitration of toluene with nitrating acid (mixture of nitric acid and sulfuric acid) in which, in a first stage, the toluene is converted to mononitrotoluene (MNT) and then the mononitrotoluene is converted in a second stage to dinitrotoluene (DNT). Control of the weight ratio of the aqueous to organic phases, dispersion of the organic phase in the aqueous phase and use of less than 2.06 moles of nitric acid per mole of toluene are key features of this process.

Abstract: A method and device are disclosed for safely operating a switching device with at least one main contact, which can be switched on or off, and which has contact elements and a moving contact bridge, and with at least one control magnet, which has a moving armature. During switching on and off, the armature acts upon the contact bridge whereby closing and opening the corresponding main contact. At least one embodiment of the method includes the following: a) identifying whether the moving contact bridge of the at least one main contact has surpassed an opening point after the switching off; and b) interrupting the further operation of the switching device when the opening point has not been surpassed after a predetermined period of time.

Abstract: A method and a device for the secure operation of a switching device are disclosed, including at least one main contact which can be switched on and off and which includes contact pieces and a displaceable contact bridge, and also at least one control magnet which includes a displaceable anchor. The anchor acts upon the contact bridge when it is switched on or off such that the corresponding main contact is opened and closed. In at least one embodiment, the method includes: a) the displaceable contact bridge of the at least one main contact recognises when an opening point has been exceeded after being switched off, and b) the additional operation of the switching device is interrupted, according to a predetermined duration of time, when the opening point is not exceeded.

Abstract: Isocyanates are produced by reacting an organic amine with phosgene in process which includes at least three stages. The first stage is carried out in a dynamic mixer. The second stage is carried out in at least one reactor. The third stage is carried out in at least one material separating apparatus. The pressure in the reactor of the second stage must be greater than or equal to the pressure in the dynamic mixer. The pressure in the third stage material separating apparatus must be lower than the pressure in the second stage reactor.

Abstract: The present invention relates to a process for the production of mixtures of di- and polyamines of the diphenylmethane series (MDA) containing less than 1,000 ppm of water and less than 200 ppm of aniline by reaction of aniline and formaldehyde in the presence of acid catalysts and subsequent separation of the acid catalyst and subsequent distillative separation of water and aniline in an at least a two-stage distillation including a flash evaporation and subsequent cooling.

Abstract: Power switches are provided with measures for preventing a recommendation of the arc from the secondary current path to the main current path and/or measures for returning the current limiter during the recommutation of the light art. A corresponding arrangement for carrying out the method is provided with means in the power switch and/or current limiter for preventing a switch failure of the current limiter disposed in the secondary current path of the power switch. The current limiter can be especially a PTC current limiter.

Abstract: The invention provides a process for the preparation of polyamines of the diphenylmethane series. This process comprises a) reacting aniline and formaldehyde in a molar ratio of 1.5:1 to 6:1, in the presence of an acid catalyst at temperatures of 20° C. to 100° C., in which the water content in the acid reaction mixture is <20 wt. % and a degree of protonation of <15% is established, and b) increasing the temperature of the reaction to a temperature of 110° C. to 250° C. when the ratio of the weight contents of p-aminobenzylaniline to 4,4?-MDA in the reaction mixture falls below a value of 1.00.

Abstract: The present invention relates to a process for the production of mixtures of di- and polyamines of the diphenylmethane series (MDA) containing less than 1,000 ppm of water and less than 200 ppm of aniline by reaction of aniline and formaldehyde in the presence of acid catalysts and subsequent separation of the acid catalyst and subsequent distillative separation of water and aniline in an at least a two-stage distillation including a flash evaporation and subsequent cooling.

Abstract: The invention provides an improved process for preparing diamines and polyamines from the diphenylmethane series by reacting aniline and formaldehyde in the presence of an acid catalyst, the improvement involving the aniline containing less than about 3 wt. % of diamines and polyamines from the diphenylmethane series, based on the weight of the aniline.