Abstract: The present invention relates to a process for the industrial preparation of a diamine starting from a corresponding alkenyl nitrile comprising at least one C—C double bond, which comprises the steps (a) reaction of the alkenyl nitrile with a corresponding monoamine in a first reactor so that the monoamine adds exothermically onto the at least one double bond to form an aminoalkyl nitrile, with the monoamine and water being charged initially and the alkenyl nitrile being fed in; (b) evaporation of unreacted alkenyl nitrile and monoamine to increase the concentration of the aminoalkyl nitrile product in the bottoms of the first reactor; (c) transfer of the aminoalkyl nitrile bottom product from step (b) to a second reactor; (d) batchwise catalytic hydrogenation of the aminoalkyl nitrile transferred in step (c) to the diamine in the second reactor, with each batch being obtained by initially charging a catalyst suitable for the hydrogenation of nitriles to amines and also water, the desired diamine and a bas

Abstract: A vacuum pump comprises a drive shaft and a Siegbahn pumping mechanism. The Siegbahn pumping mechanism comprises a rotor element located on the drive shaft and an annular stator element located about the drive shaft and proximate the rotor element, the stator element comprising a plurality of walls extending towards the rotor element and defining a plurality of spiral channels. The stator element comprises a plurality of sections, with means such as a resilient member being located about the sections to urge the sections together, and thereby inhibit gas leakage between the sections of the stator element. The resilient member can also form a seal between the stator sections and a casing located about the pumping mechanism.

Abstract: A vacuum pump comprises a housing, a drive shaft supported by a beating arrangement for rotation relative to the housing about an axis, and a pumping mechanism comprising a stator component mounted on the housing and a disk-shaped rotor component mounted on the drive shaft axially proximate the stator component. The bearing arrangement comprises a bearing supported in both radial and axial directions by a resilient support, comprising inner and outer annular portions connected by a plurality of flexible members, so that there is a fixed relation between the inner race of the bearing and the outer portion of the resilient support to determine the axial clearance between the rotor and stator components of the pumping mechanism.

Abstract: The present invention relates to a continuous process for preparing 3-aminomethyl-3,5,5-trimethylcyclohexylamine by reacting a feed stream comprising 3-cyano-3,5,5-trimethylcyclohexylimine with hydrogen and ammonia over hydrogenation catalysts, wherein the basicity of the reaction mixture is increased during the reaction by bringing the reaction mixture into contact with a basic compound which is not ammonia and/or a basic catalyst after part of the 3-cyano-3,5,5-trimethylcyclohexylimine has been reacted.

Abstract: Catalysts which are prepared by reducing catalyst precursors which comprise a) cobalt and b) one or more elements of the alkali metal group, of the alkaline earth metal group, of the group consisting of the rare earths or zinc or mixtures thereof, the elements a) and b) being present at least partly in the form of their mixed oxides, and a process for the preparation of these catalysts and the use thereof for the hydrogenation of unsaturated organic compounds. Furthermore, a process for regenerating these catalysts by treatment of the catalyst with a liquid is described.

Abstract: Processes comprising: providing a dehydrogenatable compound; and subjecting the dehydrogenatable compound to a dehydrogenation reaction at a temperature of from 150 to 400° C., in the presence of oxygen, and at a temperature profile of the dehydrogenation reaction which does not differ substantially from the temperature profile of the dehydrogenation reaction in the absence of oxygen under otherwise identical conditions.

Abstract: The invention relates to a process for hydrogenating oligonitriles which have at least two nitrile groups in the presence of a catalyst which, before commencement of the hydrogenation, is pretreated by contacting with a compound A which is selected from alkali metal carbonates, alkaline earth metal carbonates, ammonium carbonate, alkali metal hydrogencarbonates, alkaline earth metal hydrogencarbonates, ammonium hydrogencarbonate, alkaline earth metal oxocarbonates, alkali metal carboxylates, alkaline earth metal carboxylates, ammonium carboxylates, alkali metal dihydrogenphosphates, alkaline earth metal dihydrogenphosphates, alkali metal hydrogenphosphates, alkaline earth metal hydrogenphosphates, alkali metal phosphates, alkaline earth metal phosphates and ammonium phosphate, alkali metal acetates, alkaline earth metal acetates, ammonium acetate, alkali metal formiates, alkaline earth metal formiates, ammonium formiate, alkali metal oxalates, alkaline earth metal oxalates and ammonium oxalate.

Abstract: A process for hydrogenating oligonitriles which have at least two nitrile groups in the presence of a catalyst which, before commencement of the hydrogenation, is pretreated by contacting with a compound A which is selected from alkali metal carbonates, alkaline earth metal carbonates, ammonium carbonate, alkali metal hydrogencarbonates, alkaline earth metal hydrogencarbonates, ammonium hydrogencarbonate, alkaline earth metal oxocarbonates, alkali metal carboxylates, alkaline earth metal carboxylates, ammonium carboxylates, alkali metal dihydrogen phosphates, alkaline earth metal dihydrogen phosphates, alkali metal hydrogen phosphates, alkaline earth metal hydrogen phosphates, alkali metal phosphates, alkaline earth metal phosphates and ammonium phosphate, alkali metal acetates, alkaline earth metal acetates, ammonium acetate, alkali metal formates, alkaline earth metal formates, ammonium formate, alkali metal oxalates, alkaline earth metal oxalates and ammonium oxalate.

Abstract: The invention relates to a process for preparing aminoalkanamides by reacting cyanoalkanoic esters with a) ammonia or an amine and b) hydrogen in the presence of a catalyst, the reaction with component b) being started simultaneously or not later than a maximum of 100 minutes after commencement of the reaction of the cyanoalkanoic ester with component a).

Abstract: The present invention relates to a process for the industrial preparation of a diamine starting from a corresponding alkenyl nitrile comprising at least one C-C double bond, which comprises the steps (a) reaction of the alkenyl nitrile with a corresponding monoamine in a first reactor so that the monoamine adds exothermically onto the at least one double bond to form an aminoalkyl nitrile, with the monoamine and water being charged initially and the alkenyl nitrile being fed in; (b) evaporation of unreacted alkenyl nitrile and monoamine to increase the concentration of the aminoalkyl nitrile product in the bottoms of the first reactor; (c) transfer of the aminoalkyl nitrile bottom product from step (b) to a second reactor; (d) batchwise catalytic hydrogenation of the aminoalkyl nitrile transferred in step (c) to the diamine in the second reactor, with each batch being obtained by initially charging a catalyst suitable for the hydrogenation of nitriles to amines and also water, the desired diamine and a bas

Abstract: A process for preparing a xylylenediamine by heterogeneously catalyzed hydrogenation of a phthalonitrile, wherein the hydrogenation is carried out in the presence of a cobalt skeletal catalyst, of an alkali metal hydroxide and of an alcohol and/or ether as the solvent, at an absolute pressure in the range from 1 to 100 bar and a temperature in the range from 40 to 150° C.

Abstract: A process for preparing a xylylenediamine by heterogeneously catalyzed hydrogenation of a phthalonitrile, wherein the hydrogenation is carried out in the presence of a nickel catalyst, of water, of an alkali metal hydroxide and of an ether as a solvent, at an absolute pressure in the range from 1 to 100 bar, at a temperature in the range from 40 to 150° C. and without addition of ammonia.

Abstract: Apparatus and a method are disclosed for providing a priority queuing arrangement in the transmit direction in Inter-Working Units (IWUs) that permits Frame Relay data packets or ATM cells from channels that have contracted for a particular level of bandwidth service to be provided that service, even during heavy traffic periods when there is contention for resources in the IWU.

Abstract: The present invention relates to processes and products made of a natural component being cashew nut shell oil (CNSO) and another component being di- and/or polyisocyanates. Since the CNSO is a mixture of a biphenol and a fatty acid, both of which have a benzenoid ring with phenyl radicals and side chains, one of which has three double bonds, the isocyanates can react on three different levels:I. The COOH of the fatty acidII. The OH of the phenyl radicalsIII. The double bonds of the chains.